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View Full Version : Garrett GT Turbos, here is why they are better.



Hollywood
05-13-2004, 04:20 PM
Here is some info for people to check out. Most people understand that the Garrett GT turbos are superior to the older lines but here are the reasons why and some comparisons;

T04B, old school technology, 20+ years old!
T04E, older technology but still used due to part availability and it is considerably cheaper because of this. Many companies rebuild this turbo as well competition reduces cost and maintenance.
T04S Newer Race/GT housing 4" inlet standard.
T04R 1 word "hardcore!" For full out drag race cars.
Then there are a series of GT housings.

Here is why GT turbos are better;

1. Improved Aerodynamics - The modern GT wheel is the result of decades of development and testing using the latest technology and tools.
-Many "T" applications are based upon older/outdated wheels from the previous decades.

2. Better wheel match/ratio: Each turbo consists of a careful matched turbine and compressor wheel that is known to work extremely well together which also, allows the combination to reach the highest level of operating efficiency.
-Many "T" applications are randomly selected combinations based solely upon a compressor flow requirement or a turbine flow requirment in relationship to an engine size. As a result, a lot of "untested" combinations are used.

3. The GT's larger A/R housing allows the turbo to reach peak turbine efficiency. Not only is backpressure reduced, but the increased turbine efficiency allows the turbo/engine to make better power across the entire RPM band. A large A/R "GT" Turbo with a good wheel combination will outperform a small A/R "T" in both spool-up and power.
- In many "T" applications, the selection process for the A/R size is influenced by the desire to have boost at a certain RPM range. Here, the tendency is to use a small A/R as an attempt to shift the boost curve to the lower RPM. As a result, the selected turbine wheel is not allowed to reach it's peak efficiency because of the small A/R. The overall result is a lazy turbo that is not efficient, a combination that only looks good on paper.

4. The GT Ball Bearing makes a good turbo even better. The low friction design offers less drag on rotation and endures thrust much better than journal bearing turbos. Better transient boost response makes the turbo much more responsive during both cruising and wide open throttle driving conditions. By reaching full boost sooner, the GT Ball Bearing turbo makes more power available sooner, negating the need to "rev out" the engine constantly.
- Many "T" turbos can make the high peak HP numbers, but only the GT Ball Bearing turbos make the high HP and offer a power curve with a wider torque band that spreads the power across a more usable range. A high torque number is no good if it is reached 200 RPM before redline.

5. The last reason to switch to GT is: Its now easy to do with a drop in turbo design. No major reconfiguring of the turbo kit is necessary. In most cases, all major hardware such as manifold, downpipe, pressure pipes, etc. is retained.



Enjoy yourself!

Loose
05-13-2004, 05:22 PM
you left out price!

milesmcewing
05-13-2004, 05:49 PM
LOL

Hollywood
05-13-2004, 07:37 PM
Originally posted by Loose
you left out price!

What does price have to do with why they are in technical terms better?

Redlyne_mr2
05-13-2004, 09:31 PM
I'm saving up for a gt28rs, should be a nice turbo for my car

Inthered
05-13-2004, 10:42 PM
^^ I would love to get that turbo for one of my cars!! I read some crazy reports about it.

Kor
05-14-2004, 02:21 AM
I really like your post. Basically, its all true. The GT series turbos are the best.

However, there are some points I would like to make, just so that both sides of the coin are being presented.

One, just because a turbo's design is old does not mean its bad. The older T series turbos are "proven".

Two, really its not about the turbo but how you use it. You can build a turbo system with an older T3 or T04 series turbo that will perform just as well as a GT series turbo. By just as well, I mean it will spool similarly and yeild similar hp/torque. You might find this hard to believe - but what it comes down to is properly sizing the turbo to the engine and application. Although you point out that "many T applications are randomly selected" the truth is that the selection process is not random. Well, for some people it IS random, and they end up dissatisfied. But for others, the process is scientific, and you get a very well tailored turbo.

Three, price. You can honestly buy 3 to 4 older T series turbos for the price of 1 GT series turbo. Or, you can put the money you save into supporting modifications (such as an intercooler, exhaust or intake improvements). For any given amount of money, I think you can probably build a better system with the T series just because you will be able to buy more other stuff.

Finally, fourth. I disagree that its easy to drop in a GT series turbo. The flanges and bolt patterns are largely different. As far as I know, the majority of hardware (manifolds, downpipes) that exists for T3 or T4 applications absolutely will not bold directly to a GT turbo?


I would just like to say though, that I am a big fan of the GT series turbos. They do have a wider power band, and its easier to have a "one size fits all" attitude with the GT turbo because to a large extent its true. They do have slightly higher efficiencies (although this is often exaggerated). They are newer in design and probably more durable.

Great post! Any comments on what I wrote above?

lude_conduct
05-14-2004, 02:33 AM
That's just it though. The T series would spool similarly to a GT, but won't be making the same power. Or it will have noticable lag, and make the same power. That's pretty much the whole point to upgrading to a GT series, you get the best of both worlds.

Kor
05-14-2004, 02:42 AM
I think it can spool *similarly* to a GT and make the same power.

Impossible you say, the efficiency dictates the power at a given airflow. Yeah, true.

But, is the difference big enough to notice?

More importantly, can a person compensate for the difference by spending money elsewhere?

If you compare compressor maps, you can match a T series pretty closely as a GT series.

IMO the turbine side is where the problem lies. The GT series can have a larger A/R but still spool quickly. On a T you need a smaller A/R. You can also go from a stage 1 to slightly larger stage 2/3 wheel for more flow at the same A/R but again you are sacrificing spool time. Its a balancing act I guess.

Some people are now supplying a T3/T04e turbo with a GT wheel. So, you get the better aerodynamics of the GT wheel as well!

There is such a thing as spooling too early (this is driver preference I guess). On a VW 1.8T for instance, I think it delivers boost too soon. I would like the stock boost to come on 500 rpm's later.

Anyhow, I was most interested in the comment that you could bolt up a GT series turbo as a straightforward upgrade...

Hollywood
05-14-2004, 08:32 AM
Originally posted by Kor
One, just because a turbo's design is old does not mean its bad. The older T series turbos are "proven".



Well it kinda does actually. T04B compressors are less effecient, T04E's are good still, many configurations you would not use the T04S and above compressors anyways. But in the GT3x adn gt4x line there are housings specifically designed for the GT wheels that specific configuration will yeild more performace out of those turbos.


Originally posted by Kor
Two, really its not about the turbo but how you use it. You can build a turbo system with an older T3 or T04 series turbo that will perform just as well as a GT series turbo. By just as well, I mean it will spool similarly and yeild similar hp/torque. You might find this hard to believe - but what it comes down to is properly sizing the turbo to the engine and application. Although you point out that "many T applications are randomly selected" the truth is that the selection process is not random. Well, for some people it IS random, and they end up dissatisfied. But for others, the process is scientific, and you get a very well tailored turbo.

Three, price. You can honestly buy 3 to 4 older T series turbos for the price of 1 GT series turbo. Or, you can put the money you save into supporting modifications (such as an intercooler, exhaust or intake improvements). For any given amount of money, I think you can probably build a better system with the T series just because you will be able to buy more other stuff.



Older T3's perform just as well? No I dont think so, older T3/T4's ya with the proper trims and housings a good turbo still can be selected from that line, but it wil have less peak hp and will spool later, and have a good chance of more back pressure as well which is a negative.

In this post money is not an issue as I am compairing performance not costs.


Originally posted by Kor


Finally, fourth. I disagree that its easy to drop in a GT series turbo. The flanges and bolt patterns are largely different. As far as I know, the majority of hardware (manifolds, downpipes) that exists for T3 or T4 applications absolutely will not bold directly to a GT turbo?




Nope the exhaust side of GT3x is still the same as a regular T3. The flange is the same, but they offer the 4 bold exhaust side standard over the 5 bolt which is better anyways. The center section is the same as well as far as the oil and coolant feed ins. The only difference is you need to run a restrector on the oil side for the GT.

Another example is if you have a GT25R, and take my car for example, it bolts right up as it still has a t25 exhaust flange, and still is a T2 center section, and the turbo fully fits on my car, just the question is on some cases do they have room for the T04s compressor with other cars?

Kor
05-14-2004, 09:56 AM
I kind of qualified my own statement in the next sentence, "By just as well, I mean it will spool similarly and yeild similar hp/torque." My main point was, its not about the turbo but how you use it. Because in theory, yeah the GT will perform better, no question. But in practice, I am not sure this is true. What you are saying, is the GT series are better. What I am saying is, a car with a well chosen T series could perform as well as a car with a GT series turbo. So, although the turbo is not as "efficient" the car itself is going to be better. What is a better car? Well, maybe faster drag time, or auto-x time. It depends on what you pick the turbo for.

I will agree with you that for sure you can't make boost sooner AND make more peak HP with the older line. But you could make boost sooner OR make more peak HP. So depending on the application of the car, you might have chosen a better turbo for that application. Example: auto-x, you would want more torque down low, while drag, you want more peak HP. A given GT turbo is not going to be better for both drag and auto-x than if you choose a T series turbo specifically for one or the other. So, the GT is more versatile in my mind, but not "better".

I might be wrong, but I just want to be clear on what I mean.

On a side note, I think leaving money out of the post is ridiculous. Thats like saying "look, a VW Golf is faster than a Civic". Then someone might say, well, they are different prices. And they might add, given some mod money for both cars, I can make the civic faster. That is a worthwhile contribution. It might sway someone into thinking the civic was "better performance". Not a great analogy, but I am tired.

Basically, a T3 or T3/T4 would be what I would want as an alternative to say a GT28RS, the exhaust side of those two is definitely not the same though right? So if I already have a T3 and want a GT28 I am out of luck, unless I want a GT3x... but I definitely don't, a GT3x is too big :) So the upgradability kind of depends on the car.

Anyhow, I like this conversation, I am not tryin' to be a dick or anything, just want to argue for argument's sake ;)

gpomp
05-14-2004, 12:25 PM
Here's a GT28RS with a T3 housing...

http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=GRT-TBO-004&Category_Code=GRT

Hollywood
05-14-2004, 01:34 PM
Originally posted by Kor
What I am saying is, a car with a well chosen T series could perform as well as a car with a GT series turbo. So, although the turbo is not as "efficient" the car itself is going to be better. What is a better car? Well, maybe faster drag time, or auto-x time. It depends on what you pick the turbo for.



A regular T will perform close in some cases, but never as good. The guy doing drag will be faster with the GT, the guy doing autocross will be faster. With the GT.Hands down no questions asked.


Originally posted by Kor
I will agree with you that for sure you can't make boost sooner AND make more peak HP with the older line. But you could make boost sooner OR make more peak HP. So depending on the application of the car, you might have chosen a better turbo for that application. Example: auto-x, you would want more torque down low, while drag, you want more peak HP. A given GT turbo is not going to be better for both drag and auto-x than if you choose a T series turbo specifically for one or the other. So, the GT is more versatile in my mind, but not "better".

I might be wrong, but I just want to be clear on what I mean.


Unfortunately you are wrong. There is not only “one” GT turbo to pick from. While you pick a specific T3/T4, you would pick a specific GT for your racing desires. You cant compare a GT30R say to a T3/T4 50 trim, then compare it to a T76 at the same time, but then you could compare a T3/T4 50 trim to a GT25R or GT30, and a T67 to a GT42R. You have to compare apples to apples son.


Originally posted by Kor
On a side note, I think leaving money out of the post is ridiculous. Thats like saying "look, a VW Golf is faster than a Civic". Then someone might say, well, they are different prices. And they might add, given some mod money for both cars, I can make the civic faster. That is a worthwhile contribution. It might sway someone into thinking the civic was "better performance". Not a great analogy, but I am tired.

It’s not ridiculous, this is where you fail to comprehend.

“Do you understand the words coming out of my mouth?”
This was an informative post not ment to compare money or value but to compare the 2 styles of turbo’s and their technical differences. Not sure how many times I have to repeat this.


Originally posted by Kor
Basically, a T3 or T3/T4 would be what I would want as an alternative to say a GT28RS, the exhaust side of those two is definitely not the same though right? So if I already have a T3 and want a GT28 I am out of luck, unless I want a GT3x... but I definitely don't, a GT3x is too big :) So the upgradability kind of depends on the car.

Anyhow, I like this conversation, I am not tryin' to be a dick or anything, just want to argue for argument's sake ;)

Again where you lack in knowledge as explained above there is a T3 version of the GT28RS.

If you want to argue, make your have the technical knowledge to back up what you say, because so far it’s been a waste of my time to point out your technical ineptness, it’s obvious you do not understand fully, due to repeating your same arguments and contradicting yourself all over your posts in this thread.

I try to display some good technical info for people to read up on and then have to spend time trying to undo pollution from people who think they know what they’re talking about. It’s rather annoying. And if one insists on arguing for only the sake of arguing then they have issues.

M_Power
05-14-2004, 05:12 PM
Kor, this post was never intended to make a statement that you should or should not buy a GT series turbo over a T4 or any other. It was just posted to inform beyond of the obvious advantages that the new technology of these turbos has. No need to have an argument over it.

Hollywood
05-14-2004, 05:19 PM
Originally posted by M_Power
Kor, this post was never intended to make a statement that you should or should not buy a GT series turbo over a T4 or any other. It was just posted to inform beyond of the obvious advantages that the new technology of these turbos has. No need to have an argument over it.

Exactly!:thumbsup:

Maxt
05-14-2004, 07:02 PM
I guess I will just add that it probably depends on the car and exactly what turbo you are comparing the GT series to..
Alot of people jumped on the GT band wagon in the rotary world, but failed to realize any magical gains over other older model turbos... The Gt3540 was supposed to be the 500 rwhp turbo, but I don't think anyone got near that on the 3540..
On a rotary, there is so much exhaust energy, the BB option really doesn't seem to really diminish spool time over standard bushing style bearings...
Check this out
http://www.catenet.net/graph.php?car1=1&car10=1&car11=1&car7=1&car53=1&car55=1&car56=1&car73=1&car117=1&SUBMIT=GRAPH

The GT are not the fastest spooling, and are "within" the pack when it comes to HP... Some of the older models seem to work better than the GT, on the 13b, which seems to hit a back pressure wall on the GT series.. There are some refinements, but they are far from any kind of quantum leap in turbo technology..maxt

Hollywood
05-14-2004, 08:33 PM
Originally posted by Maxt
I guess I will just add that it probably depends on the car and exactly what turbo you are comparing the GT series to..
Alot of people jumped on the GT band wagon in the rotary world, but failed to realize any magical gains over other older model turbos... The Gt3540 was supposed to be the 500 rwhp turbo, but I don't think anyone got near that on the 3540..
On a rotary, there is so much exhaust energy, the BB option really doesn't seem to really diminish spool time over standard bushing style bearings...
Check this out
http://www.catenet.net/graph.php?car1=1&car10=1&car11=1&car7=1&car53=1&car55=1&car56=1&car73=1&car117=1&SUBMIT=GRAPH

The GT are not the fastest spooling, and are "within" the pack when it comes to HP... Some of the older models seem to work better than the GT, on the 13b, which seems to hit a back pressure wall on the GT series.. There are some refinements, but they are far from any kind of quantum leap in turbo technology..maxt

Roteries are a little differerent obviously and only make up a small percentage of whats on the road.

On that graph, you know the difference in porting in roteries make a huge difference yet only some ports are listed, just question marks on others, 1 port can mean totally different power compaired to another.

But the T88 aside as it power rage is considerably diferent than all the others, the next two on top are the T04S, and the GT 35/40, both which i mentioned above as being newer better technology then the 3rd id the apexi RX6, which again specializes in ball berring and better spooling wheels.

I'm not comparing GT's to other brands just compairing Garrett to Garrett. As if one is looking for ultamate turbos HKS's are very popular and they make their own housings.

Maxt
05-14-2004, 09:41 PM
Most likely most of the motors are stock port or mild street porting, if someone has a bridgeport, they are probably not gonna be running those size turbos, they are pretty much all to small for a bridge to make it worthwhile..
Rotaries are only different from smaller 4 bangers in that they like a more exhaust flow than other similar sized engines....And thats part of the problem with the GT series, it seems Garrett has if anything tried to just improve spool characteristics, and they have matched their compressors to overall, smaller turbines , at the expense of top end flow...The gt 3540 is a decent comp, but on a T3 footprint and housing configuration, it chokes up early, this would also show up on a v-8 as well as a rotary, and thats where being able to use old T4 frames generally allows a user to tune to higher peaks than the GT so far.. If I was to run a T04e, I could cheaply and easily swap to about 8 different turbines to optimize the hots side.. Not so with the GT....Yet....Maxt

Hollywood
05-14-2004, 10:50 PM
Originally posted by Maxt
Most likely most of the motors are stock port or mild street porting, if someone has a bridgeport, they are probably not gonna be running those size turbos, they are pretty much all to small for a bridge to make it worthwhile..
Rotaries are only different from smaller 4 bangers in that they like a more exhaust flow than other similar sized engines....And thats part of the problem with the GT series, it seems Garrett has if anything tried to just improve spool characteristics, and they have matched their compressors to overall, smaller turbines , at the expense of top end flow...The gt 3540 is a decent comp, but on a T3 footprint and housing configuration, it chokes up early, this would also show up on a v-8 as well as a rotary, and thats where being able to use old T4 frames generally allows a user to tune to higher peaks than the GT so far.. If I was to run a T04e, I could cheaply and easily swap to about 8 different turbines to optimize the hots side.. Not so with the GT....Yet....Maxt

Keep in mind many V-8's use twin turbos, this is where the GT's will shine. Not to mention the hybrid GT's, gt parts on other garretts.

Not everyone is tunning to the extreme (ie:full out T76 etc) but to prove to you, you tell me what turbo do you need for for 550whp on your car?

milesmcewing
05-14-2004, 11:13 PM
I feel compelled to comment!

Please note I have put my comments in quotations after your original points, sorry that I don't know how to stick them as quotes. Please note that I am not trying to start a war, I am just adding my views, based on my experience.


Here is why GT turbos are better;



1. Improved Aerodynamics - The modern GT wheel is the result of decades of development and testing using the latest technology and tools.
-Many "T" applications are based upon older/outdated wheels from the previous decades.


"GT wheels are based on the same theories of airflow that the "T" series are based on, and the turbos dating to the 1930's, yes it is true they are using newer technology and tooling to build them, that doesn't make it better. Physics are still physics"




2. Better wheel match/ratio: Each turbo consists of a careful matched turbine and compressor wheel that is known to work extremely well together which also, allows the combination to reach the highest level of operating efficiency.
-Many "T" applications are randomly selected combinations based solely upon a compressor flow requirement or a turbine flow requirment in relationship to an engine size. As a result, a lot of "untested" combinations are used.


"Not necessarily better matches, Gt turbos are subject to the same people using your "randomly selected combinations" (only there are not as many combinations). We test many turbos for the manufacturers, our testing helps qualify these combinations for both series. Better matching to the requirements and application are key no matter whose turbo you use.:



3. The GT's larger A/R housing allows the turbo to reach peak turbine efficiency. Not only is backpressure reduced, but the increased turbine efficiency allows the turbo/engine to make better power across the entire RPM band. A large A/R "GT" Turbo with a good wheel combination will outperform a small A/R "T" in both spool-up and power.
- In many "T" applications, the selection process for the A/R size is influenced by the desire to have boost at a certain RPM range. Here, the tendency is to use a small A/R as an attempt to shift the boost curve to the lower RPM. As a result, the selected turbine wheel is not allowed to reach it's peak efficiency because of the small A/R. The overall result is a lazy turbo that is not efficient, a combination that only looks good on paper.


"A/R ratio is a mathematical calculation. (read Corky Bell or Hugh Macinnis for a detailed explanation) A larger A/R ratio is larger no matter what series you use. Using different A\R ratios to shift the boost curve is someones knowledge trying to match the turbo to your application, lazy and inefficient means you have the wrong guy matching your application. Buying the wrong GT series isn't going to work any better than buying the wrong "T" series."



4. The GT Ball Bearing makes a good turbo even better. The low friction design offers less drag on rotation and endures thrust much better than journal bearing turbos. Better transient boost response makes the turbo much more responsive during both cruising and wide open throttle driving conditions. By reaching full boost sooner, the GT Ball Bearing turbo makes more power available sooner, negating the need to "rev out" the engine constantly.


"GT ball-bearing turbos are suffering from many bearing failures, yes they can spool faster, but the tolerances required for operation at 120,000 RPM are very small, the bearings are much less tolerant of cheap oil, hot shutdowns, infrequent oil changes, and manufacturing defects. Think about this ' if ball-bearing design is so much better, how come crankshafts, connecting rods, and camshafts ride on bearing shells?' Even Formula one engines still use bushing technology. If you need to Rev out the engine constantly, yet again someone has mismatched the turbo for your application."




- Many "T" turbos can make the high peak HP numbers, but only the GT Ball Bearing turbos make the high HP and offer a power curve with a wider torque band that spreads the power across a more usable range. A high torque number is no good if it is reached 200 RPM before redline.


"The torque band is a function of the combined A\R, intake wheel, trim side, hot housing etc. etc. Yet again this statement supports the mismatch issue"



5. The last reason to switch to GT is: Its now easy to do with a drop in turbo design. No major reconfiguring of the turbo kit is necessary. In most cases, all major hardware such as manifold, downpipe, pressure pipes, etc. is retained.


"Not true, the bearing housing is considerably larger, most applications using "T" series turbos will need some fabrication to "drop in"



"Most of the statement you have provided point to a marketing sense, the GT series certainly is a refinement of the T series, however the bugs are not worked out yet. If you blow up a T series, usually you can rebuild the turbo, with the GT series, the cartridge is non-rebuildable. "

"Lastly, the most important factor in turbocharging is still getting someone who can identify your application and size the turbo to match your requirements, deal with a reputable shop and make sure when they ask you what you want you tell them truthfully, a lot of people call wanting a drag turbo with a million horsepower, try living with that unit everyday and you will be sorry (unless of course it is for a drag-only car)"

Cheers to all!

rage2
05-15-2004, 12:17 AM
Miles makes some good points, but one thing he didn't point out is that the GT turbos DO in fact seem to have more grunt low end... building boost earlier, etc. Not sure why, maybe it's the BB design, maybe it's a more "magical" wheel, or maybe the compressor maps are lying ;). The compressor maps are generally a lot more "wider" than your average T series turbos.

Until I see one in action that I get to muck around with, I'm not gonna jump on the GT bandwagon. I too have been reading up on mixed results on the GT series turbos, money being the biggest negative comment.

Kor
05-15-2004, 01:35 AM
Originally posted by milesmcewing
- In many "T" applications, the selection process for the A/R size is influenced by the desire to have boost at a certain RPM range. Here, the tendency is to use a small A/R as an attempt to shift the boost curve to the lower RPM. As a result, the selected turbine wheel is not allowed to reach it's peak efficiency because of the small A/R. The overall result is a lazy turbo that is not efficient, a combination that only looks good on paper.

Using different A\R ratios to shift the boost curve is someones knowledge trying to match the turbo to your application, lazy and inefficient means you have the wrong guy matching your application.

Lastly, the most important factor in turbocharging is still getting someone who can identify your application and size the turbo to match your requirements, deal with a reputable shop and make sure when they ask you what you want you tell them truthfully

Cheers to all! [/B]


This post is pretty good, lots of people are contributing both facts and opinions! Miles, I am definitely going to talk with you before selecting a turbo :)

milesmcewing
05-15-2004, 07:54 AM
I will be at V8less today, feel free to come by and I would be happy to chat.

I agree with Rage2, I think the reasoning is that the GT series are more tolerant of mismatch.
I used to believe strongly in the compressor maps, until Majestic sent us three turbos that should not work according to the maps, all three were dramatically different and performed waaaay outside the expectation. (This was Kevin proving me to be a fool, when I tried to call him on some book-smart theory, he showed me the real-world example.)

Just for background information, Majestic Turbo invited us to Bonneville to see the work they were doing, bikes doing over 300MPH, Cars that do 450MPH. We saw a pickup truck that had twin turbos from a barge, you could fit your whole head into the intake housing! Several engineers from "the big three" were there doing developmental turbo work with Kevin, unbelievable things in the works.

Kevins personal ride is an 1100HP Harley. We also travelled to Texas to work in the shop there to get a better understanding of application. My brain hurt a lot after having Kevin fill it up for 3 weeks.

Happy trails

Maxt
05-15-2004, 08:34 AM
Originally posted by Hollywood


Keep in mind many V-8's use twin turbos, this is where the GT's will shine. Not to mention the hybrid GT's, gt parts on other garretts.

Not everyone is tunning to the extreme (ie:full out T76 etc) but to prove to you, you tell me what turbo do you need for for 550whp on your car?
And alot of if probably not more v-8's use big singles like T-76's, T-88's etc etc, they shine to do they not...
The GT series is not that new, schwitzer has has a cross reference available for some Gt applications for 10 years, in fact the GT 40/42 had diesel applications that are no longer even in production by garrett, and schwitzer , holset have made drop in replacements for them..
For 550 whp, a greddy T-88 would do it, Apexi Rx-6, HkS T51 kai, TA45 garrett, maybe a T-70/72/76....
I have yet to see a dyno graph of GT series actually make huge numbers, alot of places claimed huge numbers when they developed their GT kits for the Rx-7, but none of this kits actually made the power..Places like XS and what not were claiming 500 rwhp on the 3540, but purchasers of their kits never broke 400 rwhp....100 rwhp discrepencies leaves people with a bad taste and a sore ass...
I have seen it happen on the rotary forums, everyone just got all trendy and "had to have" for the new Gt's, but the fastest cars were still running either mitsubishi turbo's or old T-series variants...
The truth is , its about optimizing the turbo to the engine, buying a GT for its new technology will not make a silk purse out of a sows ear if you no nothing on turbo sizing, and tuning... Like Rage said, it may help on some cars where people have boughten the totally wrong turbo for their car,but for the most part, there are "recipe's" out there for most cars, and certain engines suit certain turbos, while the GT may look like a god send for one guys car, its overpriced lemon on another...
Somethings I don't like about the GT, is that they have a overall smaller turbine shaft for a given flow rate, than alot of other turbo's no sure how long the would handle surge for, another downer, is that the turbine shaft threads into the comp wheel instead of being held in place by a nut ala 99.9% of all other turbos', this means you are totally stuck to GT series comp wheels, should destruction happen, the wheel has more of chance of backing off with that design, or you wanted to hybrid the design to a higher flow rated compressor or try another make of turbine on the turbo to incorporporate an oem style wastegate or manifold..
Alot of people are saying, oh look it decreased lag by 200 rpm on the same car, but with a differenct manifold :rolleyes: , I decreased lag on my car by 400 rpm just by porting the throttlebody..
There are some design improvements or differences, but it does not make them "better"....
Don't let marketing get to you so much...Maxt

Hollywood
05-15-2004, 10:40 AM
Originally posted by Hollywood
you tell me what turbo do you need for for 550whp on your car?



Originally posted by Maxt
For 550 whp, a greddy T-88 would do it, Apexi Rx-6, HkS T51 kai, TA45 garrett, maybe a T-70/72/76....


I think the Nissan community is a little above from what I'm hearing. There was a time where there was mixed feelings from GT's, but now those mixed feelings are gone as proof is starting to show up and the community is all over GT turbos.

While Maxt in his rx-7 needs a very large turbo for 550whp in 4 cyl standards, here is an example of GT Technology;

SC61, SR20DET 2L, standard performance mods.
http://www.enjukuracing.com/ken/racecar/544.jpg

Car has gt25r, 264 step 1's, z32maf, 740cc, rspl, and profec B.
http://www.planb-attack.com/jay/dyno.jpg

Hollywood
05-15-2004, 10:55 AM
Originally posted by rage2
Miles makes some good points

His main point in which I 100% agrre on is you need to have the right turbo for your application no matter what brand or type. An HKS 3037 may be good fro a wrx, but no so good for your chevy sprint. But this is obvious.

I will agree the BB center section is a little more hassel oil wise, but treated right it will take the abuse and supposidly last longer and able to take more of a beating, this I cannot proove but it supposed to be one of it's selling points. If there are stories of people blowing GT's my first question is did they use the proper restrictor or any restrictor at all as the GT's need less oil than regular.

They basically do drop im from a T3 to a GT/3 turbine or a T25 to a GT25, shit even on the SR the hardlines bolt up to the center section of the GT25 when clocked right, you dont even need new lines. The only thing I would say can be tough is the 4" inlet on some of them, if someone has to modify a down pipe big deal or lines dont match up, big deal braided lines, neither seem too much of troubling tasks.

dishrag
05-17-2004, 09:35 AM
the clincher is the non-rebuildability of the GT's. I only know of one place that "says" they can rebuild them. Gt's are the Mach3 razor of turbos - they might be damn good, but the initial price is high and you are stuck buying one brand of overpriced replacements. With less parts and less friction they could very well last a long time, but who wants to be the guinea pig?

Hollywood
05-17-2004, 10:09 AM
Originally posted by dishrag
the clincher is the non-rebuildability of the GT's. I only know of one place that "says" they can rebuild them. Gt's are the Mach3 razor of turbos - they might be damn good, but the initial price is high and you are stuck buying one brand of overpriced replacements. With less parts and less friction they could very well last a long time, but who wants to be the guinea pig?

I dont know why price keeps comming into this thread. So now that I am annoyed of it being brought up again. You go price out a new Blitz, or HKS, or Greddy turbo and then come back to me bitching about price of a GT and you will be singing a different tune.

Prices are in US.

------
HKS GT3037 - 420/440/470 PS Output
COMPRESSOR:
-Wheel- 48/52/56 Trims - 52.8/55.0/57.0 Inducers / 76.2 Major
-Housing- 70 Inlet / 50 Outlet - 0.60 A/R
TURBINE:
-Wheel- 84 Trim - 60.0 Major / 55.0 Exducer
-Housing- GT25 inlet / External GT30 outlet; 0.61, 0.73, 0.87, 1.01, 1.12 A/R

Part No. Application Trim A/R Flange Type Wastegate
Type Price
1401-RA107 *General Application* 48T 0.73 T25 Flange External $2695.00
-----
Greddy
Part Number: 11500210
Model: All -
This applies to all makes and models. Please check your applications and ensure this product serves the specific need you have.
Desc: T67 (25G)
Notes: w/ flanges gaskets & hardware
Price: $2 200.00
Type: external
----
Apexi
716-xxxx IHI Turbocharger assembly RX6 Ball Bearing --- $2,200.00


Now GT prices

--
Garrett GT3037
FULL STEEL BALLBEARING CENTER SECTION
Ported shroud compressor housing, allowing for a more effecient compressor.
compressor specs: GT37 w/ported shroud
.60 a/r
compressor wheel trim: 56 trim wheel
compressor flow: 53 LB/MIN
turbine specs:T3
.63 a/r or .82 a/r
84 trim wheel
Water cooled and oil lubricated bearing housing standard.
full steel ball bearing cartridge, not ceramic...
price: $1,199.00
--
Garrett GT35R
FULL STEEL BALLBEARING CENTER SECTION
compressor specs: TO4S housing
TO4S: .70a/r
compressor wheel trim: 56 trim wheel
compressor flow: 60 LB/MIN
turbine specs:T3
.63 a/r, .82 a/r or 1.06 a/r
84 trim wheel
Water cooled and oil lubricated bearing housing standard.
full steel ball bearing cartridge, not ceramic...
price: $1,379.00

The Garrett GT turbos are in some cases are half the price of the brand name turbos above. I am compairing apples to apples here, and not standard T series turbos. And thats not even bringing up the hybrids which are even cheaper still.

Kor
05-17-2004, 10:21 AM
I don't know why price is so annoying to ya, sorry :)

But for the more expensive one, it says "w/ flanges gaskets & hardware" so its almost a kit... the GT is just the turbo...

Anyhow, you can even get a used T series on beyond.ca right now for 200 bucks, so thats a huge difference.

heavyD
05-17-2004, 12:16 PM
Originally posted by Kor
I don't know why price is so annoying to ya, sorry :)

But for the more expensive one, it says "w/ flanges gaskets & hardware" so its almost a kit... the GT is just the turbo...

Anyhow, you can even get a used T series on beyond.ca right now for 200 bucks, so thats a huge difference.

Ha Ha. I've seen alot of guys who have bought used turbos off of ebay and they were all garbage. Sometimes you get a decent used turbo that will last a while but alot of them are on their last legs.

Here's one of many examples:
http://dsmtuners.com/forums/showthread.php?t=121164&highlight=screwed

Churchy
05-17-2004, 12:49 PM
Originally posted by Kor
I don't know why price is so annoying to ya, sorry :)

But for the more expensive one, it says "w/ flanges gaskets & hardware" so its almost a kit... the GT is just the turbo...

Anyhow, you can even get a used T series on beyond.ca right now for 200 bucks, so thats a huge difference.

Kor you are new here, so don't be an idoit. Hollywood has made some good points, I have already PM'd him about what turbo I should get. I can honstly admit (not like others) I'm not super smart about turbo stuff, but I can at least understand why he is saying price does not care. I have ordered the corky bell book to learn more though.



Originally posted by heavyD


Ha Ha. I've seen alot of guys who have bought used turbos off of ebay and they were all garbage. Sometimes you get a decent used turbo that will last a while but alot of them are on their last legs.

Here's one of many examples:
http://dsmtuners.com/forums/showthread.php?t=121164&highlight=screwed

Wow! Heavy D is actually making good and informative posts lately.

Maxt
05-17-2004, 05:24 PM
Originally posted by Hollywood





I think the Nissan community is a little above from what I'm hearing. There was a time where there was mixed feelings from GT's, but now those mixed feelings are gone as proof is starting to show up and the community is all over GT turbos.

While Maxt in his rx-7 needs a very large turbo for 550whp in 4 cyl standards, here is an example of GT Technology;

SC61, SR20DET 2L, standard performance mods.
http://www.enjukuracing.com/ken/racecar/544.jpg

Car has gt25r, 264 step 1's, z32maf, 740cc, rspl, and profec B.
http://www.planb-attack.com/jay/dyno.jpg

Thats very nice and all, but what fuel, what boost pressure, and what other mods, flyweel or rwhp... If you want to race gas and high boost pressures, as I would assume those dynographs are, I would raise the output level of the turbos I posted to 700hp+...
If you think all that came from just running a Gt over anything else, you are drugs.....
Why does price keep coming into?? because generally unprovable magic horsepower assumptions are not worth an extra 500 dollars +, unless you beleive in hotwires....Maxt

heavyD
05-17-2004, 05:24 PM
Originally posted by Churchy
Wow! Heavy D is actually making good and informative posts lately.

Actually 90% of my posts are informative. There are alot of losers on this site and others that post just to post because they have nothing better to do or because these forums are their only form of socializing. My concept is to give helpful advice only if I am schooled on the subject and if I don't know, I listen and learn. Not like some people that say "I think", "I heard", "I'm not sure but".

Maxt
05-17-2004, 05:33 PM
Originally posted by heavyD


Ha Ha. I've seen alot of guys who have bought used turbos off of ebay and they were all garbage. Sometimes you get a decent used turbo that will last a while but alot of them are on their last legs.

Here's one of many examples:
http://dsmtuners.com/forums/showthread.php?t=121164&highlight=screwed

I bought 4 turbos recently off auctions, all are in great shape.. I scored my HKS T51 variant for 600.00 can, Its funny with this turbo, its based on a TA/TV series large frame, add a bb and you would have a GT42/45, so much for new and improved...maxt

Hollywood
05-17-2004, 07:49 PM
Originally posted by Maxt


Thats very nice and all, but what fuel, what boost pressure, and what other mods, flyweel or rwhp... If you want to race gas and high boost pressures, as I would assume those dynographs are, I would raise the output level of the turbos I posted to 700hp+...
If you think all that came from just running a Gt over anything else, you are drugs.....
Why does price keep coming into?? because generally unprovable magic horsepower assumptions are not worth an extra 500 dollars +, unless you beleive in hotwires....Maxt

Race gas on the 544, cams, stock block, gt25 was pump gas.Both were whp. No it did not come from all GT but it's enough to be considered a performace advantage.



Originally posted by Maxt


I bought 4 turbos recently off auctions, all are in great shape.. I scored my HKS T51 variant for 600.00 can, Its funny with this turbo, its based on a TA/TV series large frame, add a bb and you would have a GT42/45, so much for new and improved...maxt

K, Max, seriously, you cant compare your part buying luck compaired anyone else on the planet. You somehow always manage to score these crazy prices. Not to mention your girlfriend making japan part finding easier. So really over 90% of us out there can not relate to your buying advantages.

For reference HKS offers a BB version of the KAI,

HKS T51R KAI - 800 PS Output
COMPRESSOR:
-Wheel- 56 Trim - 70.3 Inducer / 94.0 Major
-Housing- 100 Inlet / 80 Outlet
TURBINE:
-Wheel- 76 Trim - 82.0 Major / 71.4 Exducer

-Housing- V-Band inlet / V-Band 115.5 mm outlet - 1.00 A/R
1401-RA141 *General Application* 56T 1 V-Band External $3195.00
1401-RA146 *General Application* ; Ball-Bearing 56T 1 V-Band External $3880.00

Maxt
05-19-2004, 10:28 PM
Sure you can, you just gotta learn Japanese....Actually I find most of the parts myself, my GF just facilitates my purchases, it would be alot harder without her, but it can still be done..

I dare say with race gas, I could better that dyno with a non GT turbo...I just finished reading an article on a sr20 with a t-78 that did 550 rwhp the dyno chart actually looks wider that the one above..
Overall I think one can optimize any turbo when the turbo is picked right, but I still think some engines will make more power with a certain turbo, be it older tech than newest things, alot of gt3540 owners can't match my t04e numbers, even though on paper, they should be making 50+rwhp than me..
BTW, you can stick your whole fist in the TV-51..:) max

Redlyne_mr2
05-19-2004, 11:08 PM
The T series do have potential . I as well have seen over 700whp on a 2L 3sgte with a t78. ['m glad this thread was started, it will help me learn more about the differences between the t's and the gt's and wether I should still go the the GT

Kor
05-20-2004, 02:53 AM
Originally posted by Churchy

Kor you are new here, so don't be an idoit.



Hahahaha yeah only people with high postcounts can be idiots!

I joined June '03? I am just posting because I am working on a contract overseas and have nothing else to do while at work. When I get home, I'll probably go back to just reading.

Ben
05-20-2004, 10:23 AM
Originally posted by Churchy


Kor you are new here, so don't be an idoit. Hollywood has made some good points, I have already PM'd him about what turbo I should get. I can honstly admit (not like others) I'm not super smart about turbo stuff, but I can at least understand why he is saying price does not care. I have ordered the corky bell book to learn more though.



Just as a reference, you joined 7 months after him.

Now, back on topic :)

calkai
06-10-2004, 04:01 PM
Hi:
I am new in this forum and interested in model gas turbine building.
My turbines normally utilize the garrett compressor wheels, but it is very hard to get the information about where to buy the compressor only. And It is also hard to get the information of compressor part number.

Here seem to be many experts.
Could you point out where to get the information of garrett compressor part number?

I am looking for the compressor whell of GT35R 68mm 56 Trim.
If you know the part number of this compressor or where to buy it, please kindly e-mail me.

[email protected]

Thanks in advance and very best regards

Tom

Hollywood
06-10-2004, 10:24 PM
Originally posted by calkai
Hi:
I am new in this forum and interested in model gas turbine building.
My turbines normally utilize the garrett compressor wheels, but it is very hard to get the information about where to buy the compressor only. And It is also hard to get the information of compressor part number.

Here seem to be many experts.
Could you point out where to get the information of garrett compressor part number?

I am looking for the compressor whell of GT35R 68mm 56 Trim.
If you know the part number of this compressor or where to buy it, please kindly e-mail me.

[email protected]

Thanks in advance and very best regards

Tom

CHRA part number is 706451-0005. But that is the whole compressor section only.

kevino002
11-16-2004, 06:42 PM
just got the GT2871R........WOW!!!!!!

bart
12-03-2004, 01:57 AM
GT1749VB here i come! oh i cant wait... hurry you stupid mailman.

Hollywood
12-03-2004, 09:14 AM
Originally posted by kevino002
just got the GT2871R........WOW!!!!!!

Right on man, what car? Nissan?