Need some tuning advice...

[d0n_3d]

I am going back to the track this Friday and last time I tried using my RA108 race chip for the first time and I believe I had my boost set too high (near 25 lbs) and knocked REALLY bad...up to 11 degrees...this was on 110 leaded race gas so it wasn't fuel related...I think it was the stock turbo being pushed too hard and causing too much heat...

So the concensus is that I should run 20-22 lbs on the chip and the knock should stay down. Also what should my fuel pressure be set at with the stock injectors for this chip? I had close to 50 psi with line off last time I ran (i know i know too much fuel)....maybe i should dial it down to 45 psi ? I am having big problems tuning this car correctly.

 

[8UWITH6]

Make sure you have PURE 110 in the tank, dont mix it with pump gas. Also, Id start the boost out at 20psi, and go to 22psi max. Fuel pressure should probably be in the 43-45 range depending on the chip and your scantool numbers. Take a look at the BLMs with different FP settings.

As a side note, change your plugs and 02 just for the hell of it. I usually do before I go to the track, or, right after I get back from the track. If you havent changed those 2 items since the last time you were out, I suggest it. Hope this helps, Im sure somebody else will have more to say. Just make sure the cars in good tune before going to the track. Its not worth hurting a motor. Good luck.

 

[BLACK6PACK]

25 lbs on the stock turbo is way too high. 22 psi is the max I would go. The stock turbo is just blowing hot air after 22 psi.

22psi, pure race gas, 108 chip and 43-45 psi fuel and it should run like a dream.

 

[BlackBeauty]

Originally posted by d0n_3d
I am having big problems tuning this car correctly.

Lol, you think you are having problems tuning, why not just throw an alky kit into the equation , then you'll get two more variables (turn-on point and pump speed). That's why I'm trying to deal with. Plus a leaky FP gauge.
I heard that if you go above 47psi FP, the stock injectors' spray pattern gets all screwy. But I'm not sure how that works, because if you have 43psi FP, and 22psi of boost, your FP under boost would be 65psi. But if you had 47psi FP and 15psi boost, that would only be 62psi FP under boost. So how does that work?

 

[BLACK6PACK]

It was explained before, i don't know if I quite understand, that the boost is actually pressing the front of the injector while the fp is pressing the back of the injector. So you have 45 psi of fuel pressure, 20 pounds of boost = 65lbs of fuel pressure, but you have 20 psi of boost pressure on the front of the injector relieving some of the pressure.

 

[d0n_3d]

well i am running a brand new heated o2 sensor kit and brand new spark plugs (cr43ts) and everything else is in good shape...all fluids have been changed, intercooler cleaned out....yeah i think the stock turbo sucks...can't push it otherwise it blows hot air and causes me to knock...i HAD straight 110 in the tank when i ran too...

 

[wanttogofast]

Hey whats going on Don, its Jay, the you met at the track on Saturday. Trying to link up with you to get some your knowledge on these cars. Would actually like for you to check my car out.

 

[TRENT THOMPSON]

I understand all of the above but at the end of last year I ran 24.5 # of boost with the stock turbo,inj,dp,IC, and went 12.01@112.79 with that chip. not many have been faster on a 143000 stock motor.

 

[BLACK6PACK]

The stock turbo will hit 30+ psi pretty easily. Its just not efficient there. After you get past 22 psi the extra psi is offset by the hotter air. Meaning you get deminishing returns after 22 psi. If you have really good gas and a very cold night, you may be able to run 24 psi pretty efficiently.

Down here in south florida, anything over 22 psi and it would start to knock even with c116

 

[d0n_3d]

Originally posted by wanttogofast
Hey whats going on Don, its Jay, the you met at the track on Saturday. Trying to link up with you to get some your knowledge on these cars. Would actually like for you to check my car out.

sent you an email man...

 

[d0n_3d]

Originally posted by TRENT THOMPSON
I understand all of the above but at the end of last year I ran 24.5 # of boost with the stock turbo,inj,dp,IC, and went 12.01@112.79 with that chip. not many have been faster on a 143000 stock motor.

WOW man you achieved my frickin goal! running almost a 12 flat with stock stuff that is AMAZING...you did it with the same 108 chip as me right? hmmmmmm this is giving me hope! i want to run some very low 12's before i upgrade the stock stuff here...that is impressive indeed man...that just goes to show that these cars STOCK are fast as hell

 

[TRENT THOMPSON]

this stuff is not brain surgery It can be done. you have too work at it though. but remember you don't run numbers like that until late fall when the air is real good. if you need any help attaining your goal feel free too get a hold of me. I will help you in any way I can

 

[d0n_3d]

well i think my last shot at cold air will be tomorrow night when it's supposed to drop in the 30's...i think that should be cold enough! i will be running 22 lbs of boost on the ra108 chip on 110 leaded gas and 45 psi fuel all on slicks...let's see what happens...

 

[TRENT THOMPSON]

get your sixty foot time down and you should be there I see in your sig a 1.90 short time. this is going too have too be in the low 1.6 range too attain your goals. IMO the first 60' will make it or brake it.