2g FPR in a 1g

[Mike1992]

OK so heres the deal. I'm on the stock fuel system on a ported 14b at 15 psi. Fuel trims always read lean with the AFC zero'ed out. Car cuts out under heavy throttle whenever it feels like it. A friend of mine recently gave me his stock fpr off his 97 gst. 2g's are rated at 43 psi while the 1g is rated at 37psi. I basically have a 2g motor since its built with 2g pistons so.... If I bring the mounting holes on the fpr closer togeather and mount it on my 1g rail, is it feaseable to be able to tune this with my safc2?

 

[larsrya8]

Yes it is feasible. As long as the base fuel pressure remains constant you'll be able to tune it. With 43.5 psi fuel pressure you'll be injecting 15% more fuel than if you were at 37 psi.

Good luck

 

[staticbrainwash]

Actually 1g auto's were 43psi, as 1g manuals were 37psi. I would just put it in and log it out and see if you're running rich. I just put manual injectors and an ecu into my 1g auto and with the slight mas mods i had done along with a little more boost and intercooler pipes im running real smooth.

Honestly, i'd just get an Auto's fpr. no modification would be necessary to the rail. and if you're running lean on a 37 you might end up being alright on a 43. I just say find an 1g auto fpr, and bolt it right up.

 

[eclipsegst3131]

not to intrude on this topic, but i have a 1g manual and like a previous person stated i randomly hit fuel cut at wot. if i use a fpr off a 1g auto can i just bolt it on and go, or will i need to make any corrections? i have a walbro 190 fuel pump and an apexi safc that i plan to have put in and get the car tuned in a couple weeks when the weather is better. maybe ill just put all of them intogether. but any help would be cool.

 

[Mike1992]

Well I just got back in from trying to get the 2g fpr to mount on the rail. I was successful but it was dripping even with a new oring. I've given up on the idea and im crazy frustrated. How certain are you the auto 1g fpr is 43 psi? Where did that information come from?

 

[staticbrainwash]

Search for it, I know for a fact that the auto fpr is 43psi. I have one. The info came right from this site. And an auto 1g fpr will bolt right on your 1g manual rail.

How are you guys "randomly" hitting fuel cut? Are you logging this at all?

With an safc and a 190 you can easily tune up a auto fpr, or afpr. Just make sure you're logging to know where you need to add fuel or subtract.

 

[Mike1992]

I have no idea why I'm randomly hitting fuel cut, I guess because of the higher compression ratio on my motor. I'm gonna look inot finding a auto fpr tomorrow thanks Fuel trims as of today showed 118/110/109 and on a 1990 fuel trims max at 120. This is at 15 psi on 93 octane with some race gas in it even.

 

[staticbrainwash]

hmmm, sounds like you're problem goes a little beyond me. I would try a afpr or an auto fpr and see how it goes.

 

[dsm-onster]

Yes it is feasible. As long as the base fuel pressure remains constant you'll be able to tune it. With 43.5 psi fuel pressure you'll be injecting 15% more fuel than if you were at 37 psi.

Good luck

Installing 550cc injectors only gives you 22.22% increase over stock. Why get 550s when you can rase your fuel flow 15% for every 6psi over stock? At at 49 psi base would you have 30% more fuel? nope. Just because 43psi is 15% more psi than 37 does not mean that it is going to flow 15% more fuel... According to the DSM_Tunning_Sheet_v2.1.xls found elseware on this forum, it will flow 7.8% over stock.

But ablsolutely! as long as your fuel pressure is constant, the SAFC can beused to tune out the increase no matter how small.

 

[dsm-onster]

OK so heres the deal. I'm on the stock fuel system on a ported 14b at 15 psi. Fuel trims always read lean with the AFC zero'ed out. Car cuts out under heavy throttle whenever it feels like it. A friend of mine recently gave me his stock fpr off his 97 gst. 2g's are rated at 43 psi while the 1g is rated at 37psi. I basically have a 2g motor since its built with 2g pistons so.... If I bring the mounting holes on the fpr closer togeather and mount it on my 1g rail, is it feaseable to be able to tune this with my safc2?

Don't reengineer what has already been given you just yet . . . Basically you don't have a 2g motor. you have a 1g motor w/ higher compression and 1g ECU that thinks you have a 1g fuel pressure regulator. Don't fool the ecu any more than you have to.

You have lean fuel trims and fuel cut when you shouldn't. Sounds like a boost leak. Have you ran a boost leak test recently?

 

[larsrya8]

Installing 550cc injectors only gives you 22.22% increase over stock. Why get 550s when you can rase your fuel flow 15% for every 6psi over stock? At at 49 psi base would you have 30% more fuel? nope. Just because 43psi is 15% more psi than 37 does not mean that it is going to flow 15% more fuel... According to the DSM_Tunning_Sheet_v2.1.xls found elseware on this forum, it will flow 7.8% over stock.

But ablsolutely! as long as your fuel pressure is constant, the SAFC can beused to tune out the increase no matter how small.

Oh yeah.. forgot to take the square-root. Oops.

Should've been sqrt(43.5/37) = 1.08 (calculation from DSMLink manual)

 

[dsm-onster]

Oh yeah.. forgot to take the square-root. Oops.

Should've been sqrt(43.5/37) = 1.08 (calculation from DSMLink manual)

OH. Not a problem.

Although, when going 50 or so psi, many guys have reported part throttle and idle issues and the fuel pump flows less as you raise base pressure, I'm not negating raising the base fuel pressure as a means of getting more fuel flow. Personally, i think running 37 psi base is unacceptable for performance applications. Just there's not as much an increase as many (including myself) may thing.

Your objective was in the right direction. Just keeping the math true