GT25R on Stock Fuel System

[240SXer]

I just blew my T25, so i'm getting a GT25R. I planned on getting my fuel system first then getting a GT25R, but I've got no choice now. I'm going to runa Tial 38mm wastegate. I was going to get the .5 bar (7.25psi) spring. Will that be good with a 100% stock (370cc) fuel system? Or should I go lower? Will I have to not redline? I have an EGT gauge so I guess i'll know a bit if i'm running out of fuel, but I don't want to toast my engine. The next spring down is .4 bar (5.8psi). But I don't want it to be slow (probably take me a month or two to get the fuel and ECU). So I want to go where I'm safe but still have power? Is the .5 bar good?

[Dori Dori]

You'll be fine running stock boost.

[240SXer]

There is no real stock boost. YOu mean 7.25psi I'll be fine?

[180crafter]

You dont think he will experience some lean spots??? Just curious.

[240SXer]

I guess i'll just run 5.8psi, it's not worth risking my motor just for a few extra ponies,

[240SXer]

If people can run up to 240whp on stock fuel, i'd think the GT25R would produce the same or less @7psi, but maybe not. What do I know..

[caliracer240]

I would think you could efficiently run 12 PSI or so on that turbo with a stock system. You can run 14PSI on stock turbo with stock fuel system (with a walbro fuel pump OF COURSE).... so why couldnt you run 12 on a new turbo??

[180crafter]

Just wondering if the stock injectors would be able to keep up with the increased flow at the low RPM's. One of the reasons, is that I'm gonna have todrive with my gt28rs on for a few days.

[robbbby]

I would think you could efficiently run 12 PSI or so on that turbo with a stock system. You can run 14PSI on stock turbo with stock fuel system (with a walbro fuel pump OF COURSE).... so why couldnt you run 12 on a new turbo??

Running a gt2540r at 12 psi on 370's is not going to happen.

http://auto.howstuffworks.com/turbo.htm

Give that a read, it will give you an understanding a bit on why 12psi on a stock turbo is not the same thing as 12 psi on some upgraded larger turbo.

[Dori Dori]

There is no real stock boost. YOu mean 7.25psi I'll be fine?

I meant stock like what the SR runs stock (7lbs?).

[240SXer]

Oh.. I see what you meant. Ya.. 7.25 psi is where I think i'm going. And i'll just keep my eye on the EGT

[Gladius]

Just wondering if the stock injectors would be able to keep up with the increased flow at the low RPM's. One of the reasons, is that I'm gonna have todrive with my gt28rs on for a few days.

There is no increased flow at low rpm's. He wont be able to build boost until at least 3500rpm's.

[240SXer]

Stock turbo does not build boost till about the same. So I don't see why that would differ....

[Phax]

You will be fine at 7psi. I just spun my T25 to 18psi and it was still rich with 370cc and a Walbro.

[240SXer]

Cool.. Thanks.. I've heard more that 7psi is cool then not. So I think 7psi is fine. i'll just monitor the EGT

[Movingviolation240]

I ran a GT25R on stock fuel at 10psi, so you'll be fine. I wouldn't go much past 8 though. Just to be safe. Just don't do any long hard high RPM pull's if you want to be extra careful.

I didn't experience any detonation, but on the other hand I was making 300rwhp on 'stock' boost (just an HKS actuator) and that's well above what the stock fuel system can take (in theory).

Final answer = go for 7.25

Paul

[240SXer]

I've got the .86 ar. Think it'll be fine still?

[Movingviolation240]

yea

[240SXer]

Cool. thanks.. I'm pretty sure i'm gonna go .5 bar.

[MainEvent212]

just stay out of boost till you get some fuel stuffs

[240SXer]

Movingviolation240,

Should I get it dynoed with an AF Ratio just to make sure i'm not leaning out? It's gonna take me a bit to get the fuel stuff. A month or two. I want to still be able to actually race during that time. Even if i'm only at 7psi. But I don't want to risk damage, do you think i'm 100% good, or would it be wise to get a AF ratio?