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3.1 Turbo fuel system


iTurbo

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Hello all, I have a few quick questions about the TGP fuel system.

 

1. Can a Walbro 255 ltr/hr fuel pump be made to fit in the stock location (in-tank?)

 

2. Does the TGP use a fuel pressure regulator that is compensated for boost? What is the static fuel pressure on these cars (w/FPR reference hose unplugged)

 

3. What are the stock TGP fuel injectors rated at in terms of flow?

 

4. Is an adjustable fuel pressure regulator available? Or would a universal FPR work, to adjust base pressure?

 

Thanks for taking the time to read my questions. I might be having a lot of fun with a TGP in the near future.

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1 already answered

2 Its the same as an NA car, but by the design of a FPR, it increases fuel pressure on a 1:1 ratio with boost.

 

3. 22#/hr

 

4. No, because of where the FPR is located, you would have to custom design a fuel rail setup that got rid of the stock one and added an externa (external to the fuel rail) FPR that would be adjustable. You can add one to the return line, but it will only allow you to raise the pressure above the stock setting not lower it.

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Thanks for the info!

 

Here was my idea (not really mine..) behind these questions.

 

Let's say you want to run higher boost and need more fuel. You can't exactly just drop bigger injectors in and expect your car to run great. The calibration is programed with injector size in mind and you would run way too rich. O2 feedback might take care of some of it and it may still idle OK if the injectors aren't too big. Still, your fuel curve would likely be too rich all over the RPM/load range.

 

So why not install bigger injectors (ex. 30lb/hr) and use an adjustable FPR? You could drop the base pressure down, to the point where the 30 lb/hr injectors are flowing more like 26 lb/hr injectors. At that point, I would think the O2 feedback would keep you from running excessively rich. This would also provide you with enough fuel to run a little more boost. And with a lower base fuel pressure, your fuel pump wouldn't be working as hard.

 

So what is the point of adding big injectors if all you are going to do is lower the fuel pressure down to compensate? You get a little more fuel at WOT, allowing slightly higher boost levels and safer A/f ratios. And it's easier on the pump. But if you use a rising rate of gain FPR, like this:

 

http://www.cartech.net/fmu2020.htm

 

This regulator would get installed on the fuel return line. It's job is to increase fuel pressure w/boost. Except unlike a regular boost compensated FPR, it can raise fuel pressure at different rates, not just a 1:1 ratio. So you would have near stock fuel delivery at idle and part throttle acceleration. But as boost comes on, the Cartech FPR raises fuel pressure way up, so your big injectors that you installed are once again flowing like big injectors. This could allow for very high boost levels, using stock electronics.

 

Has this been done before?

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  • 1 year later...

iTurbo/Jcrow

 

You can run 30# injectors and you won't even know they are in there. :wink: Regardless of what people say.

 

Have you been looking under my hood. :lol: I am running 30#, 2025 fpr and 255 hp pump with absolute no issues except a lot more power little or no knock retard and poor gas mileage. :roll:

 

The stock pump is only good for about 60# sustained pressure which isn't enough to really put the injectors to work using the 2025 fpr. The 255/hp works great, I can now get 75# sustained which is as high as I have gone to date. If you are running stock turbo and motor the 2020/255 may be ok. Don't really know.

 

The pump install is straight forward, it's the damn tank thats the PIA. :evil:

 

Jcrow

 

The regulators you are talking about will not lower your base fp. It will remain what ever your stock fpr is set to. These reg's go in after the stock fpr in the return line and regulate the flow/psi returning to the tank.

If you are going with a bigger turbo get bigger than 21# injectors, much bigger.

 

Jeff M has one of these RRFPR's he wants to sell. We never hooked up so I bought a new one. You might try him.

 

Hope this helps.

 

Jud

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The 2035 regulator (not 2025) is designed for you to remove your stock regulator.

SleeperTGP - So your car does not run rich with the larger injectors? Do you know what your block learn number is?

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