Daniel, yes, I'm sending you a new #75-only chip with your headgasket. Default #75 is identical to your previous one, just the additional FQS positions give you +3/+6/+9% enrichments for quick tuning adjustmensts without having to massage the air-flow signal to fool the computer (doesn't skew ignition values along with fuel). Your ARM1 didn't show any obvious problems, but the new wideband should give us some really accurate data.

"Is he running stock HG? As what i understood Dan, is that HG blow due to incorrect A/R along with higher boost."

Please review my HeadgasketDissertation.pdf file here Ultimate Headgasket. Headgaskets almost never fail from combustion pressure, but rather are burnt up from the intense heat of detonation & knocking. The hollow compression ring with 0.1mm wall-thickness in both the standard and widefire head get pitted from detonation and the ring eventually burns through (see photos in PDF file). The few gaskets I've seen that have been blown out due to combustion-pressure has been where the head was torqued down using the earlier manual procedures with lower torque-rating (torque increased in '91 manual). Or they had warped heads or improperly milled heads that caused pockets of insufficient clamping pressure.

But as long as you have appropriate air-fuel ratios, there's no worries. We've been running 25psi on Laust's car for about a now! All the guys getting 400rwhp on a 2.5L like Alan Coleman or Russ Murphy are running 21-22psi+ One of them on a standard headgasket without O-ringing for the entire season so far!

Running 25psi on a stock turbo might hurt the turbo more than the car. I've destroyed a couple of K26/6 turbos as have a couple others when trying to extra more boost. But they tend to drop boost int he upper-RPms anyway, down to 20-18psi since the air-volume of the engine is much higher there. High-boost isn't a problem if you've got fuel & ignition maps programmed appropriately. ALL of the high-boost fears have come from past experiences with upgrades trying to push high-boost using generic chips that were optimized for 15psi. Then trying to use jerry-rigged schemes to push those chips to higher boost just doesn't provide enough precision for safety or power. That's why those engines failed, improper tuning, not because of too much boost. There's a tonne of Honduhs and Supras running around with 30-40psi boost levels all the time (guess which headgasket they use ). Some of them with no wastegates because they want to force every single bit of boost through the engine!

 

danno the only thing about buying the wide band is that i don't have the money to buy one right now. I am probably going to have to wait until i can earn some more money due to the all the bills i have from this car and other things. I will just have to keep the boost low down until i can get one.

 

Danno.........Email sent.

I definitely need to get a wideband as well!! The closest dyno is about 400 miles.

 

Just a note, it appears that not everyone understands at injectors are rated at 3.0 bar. So getting 55 lb/hr injectors and then risen the FPR to 3.0 bar doesn't mean that you're in any way "pushing" it or making up for the need of a bigger injector.

So if you use 75 lb/hr injectors with stock FPR the injectors works/flows like 69-70 lb/hr injectors.

Still enough fuel for most, but this should should not be overseen when using chips mapped for different injector sizes.

 

Is there any difference in cold-start behavior based on injector size and/or fuel pressure? I know some cars (such as my Talon) act like cold-hearted ****** on a chilly day with (larger) aftermarket injectors.