Thrasher 92 Fuel Pressure.. ?..

[GrndNatnl]

I have a T-92 chip thats made to work with the STOCK fuel pressure regulator. It's run nothing but great so far, and am very happy with it. Santa dropped off some car parts for me this Christmas, and I now have a question...

I now have an adj. fuel pressure regulator (along w/ one of the gauges for the fuel rail) that I have yet to install. My question is, should I turn the fuel pressure up with this chip thats designed to work with stock pressure levels? Will it then act like the regular chips made for upgraded regs?

I had asked Scott about it before for future refrence, but I lost the e-mail. What should I set the static pressure at for the street? With around 16 psi boost range. And what should I set it at for racing? Say maybe running 100 octane xylene brew and a little more boost? Whats recommended? I just need to know what I should run the pressure at for a little better performance.

 

[Danster]

Fuel pressure should be set at 45 psi, line off (static). Street or strip. The only thing you want to adjust is the boost level at the strip with higher gas octane. But to go faster you should get a race chip Thrasher 100 or T108 for the strip.


Dannyo

 

[GrndNatnl]

I have heard some folks saying 45 psi static was "high" for the street, and mentioning running at 42 psi on the road, but wanted more feedback. Could it reduce gas milage having it higher? Or will that strictly depend on my right foot? Thanks..

 

[Danster]

I've read some people running the T92 at 42 PSI static. Mine seems to like it at 45, a little rich at the bottom, but not bad. You can try 42 if you like, however, make sure you have a scan tool to monitor timing retard (knock) or you'll be changing head gaskets.

I just set at 45 as per the instructions and forget about it!


Dannyo

 

[GrndNatnl]

Thanks guys. I'll just go with 40 or 42 psi on the street (to run strong but conserve gas). And at the track I'll bump it up to 45. Scott, is that ok with my stock-fp-reg chip?

 

[granitestategn]

Matt,

I'm no Thrasher expert, but I would think you should set your adjustable fuel pressure regulator to maintain stock pressure. (I'm sorry but I don't remember what it is.) The Thrasher chip has open-loop idle. It doesn't use the O2 sensor at idle. If your chip is for the stock regulator, it will be looking for stock fuel pressure at idle. 45 PSI may be way too rich at idle. My suggestion would be to cough up $25 bucks for a Thrasher 92 for your injectors for use with an adjustable regulator. Or you could buy a Thrasher 100 and turn the fuel pressure up to 45 PSI with the xylene mix, turn up the boost and when the fuel is gone, turn the fuel pressure back to stock and run your Thrasher 92 for the stock regulator. You'll be giving up a little performance with the stock regulator chip.

 

[granitestategn]

OOPS!

Hey Matt,

I almost forgot. I hate to mention the obvious......don't forget to turn down the boost when the xylene mix runs out!

 

[GrndNatnl]

Yeah, thats something I would surely pay attention to. (Gas gauge & xylene left )

Another reason I want a BstC controller, so that I can control all that from in the car, and much easier then popping the hood and setting the bleeder valve correctly.

Still no word from Scott! Whats your advice Scott?

Another thing: With the regular 45 psi fuel pressure chips, is it required that the fuel pressure be set at 45 constantly? Even on the street? Or can it be lowered a couple pounds for fuel conservation on the road?

 

[granitestategn]

Matt,

Setting the fuel pressure at idle with the hose off is what determines your idle mixture. After you come off idle, the ECM takes control of the fueling using your BLM table with some help from your O2 sensor. Turning your fuel pressure down at idle will not save you gas at cruise. It will just make it idle leaner. The only way you could make it cruise leaner would be to "learn" your ECM with it set at 45 PSI ( or in your case, stock PSI), unplug your O2 sensor (this will make your ECM/chip run in open loop mode), then turn your fuel pressure down a tad. Thrasher chips can run without an O2 sensor (open loop) without setting a fault code. Then keep your foot out of the boost because you will probably be lean at WOT too. Can you say "OOPS!" Better have a Scanmaster or other tool hooked up first and watch for KR. I don't know if I would recommend it, though. Why not just set the fuel pressure where it's supposed to be and keep your foot out of it. That will probably give you good gas mileage and be the safest for your engine. Oh....Happy New Year Matt!

How am I doing Scott????

If you want to hear it from the horses mouth, I would suggest e-mailing Scott directly.

 

[Scott231]

Originally posted by granitestategn
If you want to hear it from the horses mouth, I would suggest e-mailing Scott directly.

That would've been the obvious answer...

The GN and the TTA use the same injectors. The chips have different injector constants BECAUSE the TTA used the 237 regulator with the static pressure just below 45 (the 233 gives about 40psi). To make things easier, and because Tom also owned a couple TTAs, Tom chose to use the 237 regulator as the common reference for all Thrasher chips during development.

During Thrasher's heydays, a request was made for a Thrasher to work with the 233 regulator. That is what I've made available to fellow TR entusiasts. As such, if you have the 92-28-k2 variant Thrasher chip and want to add an adjustable fuel pressure regulator, fine. Just set the static fuel pressure to what it was with the 233 regulator when the car was running "great". That would be the most correct fuel pressure as that is what the chip was designed for.

With the adjustable regulator you can now use some of the other Thrashers for stock injectors and the 237 regulator such as the 97, 100 or 108 Race Thrashers. Just get some good tires first