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LUDELVR
05-26-2002, 11:47 PM
Hey guys, just wondering what are some causes for a blown head gasket on a turbo car? I want to know for future reference. Thanks

rage2
05-27-2002, 12:03 AM
high combustion temps caused by detonation.

LUDELVR
05-27-2002, 12:10 AM
Is that the only thing that can cause a blown head gasket or the most likely? I'm worried about blowing one once I get the turbo on. Cuz if it's detonation, I won't be boosting past 7 psi and I'll be running an 8:1 fmu and an inline pump. oh yah, I'll also be utilizing an msd btm to retard my ignition timing under boost. So I guess I shouldn't have to worry about detonation if I'll have ample fuel and retarded ignition timing right? Correct me if I'm wrong, please!!:thumbsup:

speedracer
05-27-2002, 12:14 AM
Make sure you don't lean out when you Redline / Bounce off the limiter.

rage2
05-27-2002, 12:18 AM
Very high cylinder pressures would cause it to fail as well, but you'll most likely run into detonation issues first.

To ensure there's no detonation, I do the following when tuning my car :

1. Tune the right fuel mixture under boost (12.5:1)
2. If there's detonation, retard the timing.
3. If there's still detonation, lower the boost.

You can also use higher octane fuel (103+ race fuel) to allow higher boost/less retard without detonation.

LUDELVR
05-27-2002, 12:41 AM
Originally posted by rage2
Very high cylinder pressures would cause it to fail as well, but you'll most likely run into detonation issues first.

To ensure there's no detonation, I do the following when tuning my car :

1. Tune the right fuel mixture under boost (12.5:1)
2. If there's detonation, retard the timing.
3. If there's still detonation, lower the boost.

You can also use higher octane fuel (103+ race fuel) to allow higher boost/less retard without detonation.

Well, the only way I'll know if I have the right fuel mixture is by being on the dyno...unless anyone has a good air/fuel meter that I can plug into my oxygen sensor!! haha
as for high cylinder pressure, I'll be running at the most 7 psi and I'll have an fmu to raise fuel pressure at a rate of 8:1 along with a fuel pump. Hey, have any of u guys heard of running to rich and then bogging out at idle because of an inline? I've heard of some people having this problem with inlines.

Ed the SOHC
05-27-2002, 12:44 AM
what's the price of race fuel?

kenny
05-27-2002, 12:48 AM
Originally posted by Ed the SOHC
what's the price of race fuel?

$10 / gallon w/ a minimum 5 gallon purchase.

rage2
05-27-2002, 08:38 AM
Originally posted by LUDELVR
Well, the only way I'll know if I have the right fuel mixture is by being on the dyno...unless anyone has a good air/fuel meter that I can plug into my oxygen sensor!! haha

You REALLY need at least a simple mixture meter (less than $100) to get a "safe" fuel curve. After getting a good decent fuel curve, then you should get a wideband O2 sensor, or strap the car on the dyno, to get the 12.5:1 ratio for best power.

Honestly, if you just add mods without any tuning or even a mixture meter, you're just asking for a blown engine.

5.9 R/T
05-27-2002, 10:14 AM
There are many more causes of detonation on a turbo car, I'll see if i can remember them all here.
1. Octane - if you don't have a high enough octane to satisfy boost levels then turn down the boost or get some octane booster.
2. High outdoor temps - especially if your not going to run an intercooler on hot days you may find yourself turning down the boost.
3. Back pressure - are you going to be using a small turbo? If so you should be warned that they tend to hold up exhaust gases more in the combustion chamber increasing temps which leads to detonation.
4. Lean AFR - less fuel = less heat absorbed = more prone to detonate. Always run on the rich side of stoich.
5. Ignigtion timing - this has been discussed already, just make sure not to confuse it with pre-ignition because they are two completely different things.

I think thats all of them. As for the bogging at idle thing I would assume that they are using a mostly stock fuel system with upgraded injectors and pump. If this is the case then fuel flow on the rail would be to much for the fuel regulator to handle and it would run stupidly rich which would cause the motor to bog especially at low RPMs. Hope this helps, good luck with your setup!

WBB6
05-30-2002, 12:30 AM
TOO MUCH BOOST!!! :angel: :angel:

LUDELVR
05-30-2002, 12:53 AM
Originally posted by WBB6
TOO MUCH BOOST!!! :angel: :angel:

Is there even such a thing?? :rofl: :rofl: ;) ;)