reborn92rs

I have to replace my gas tank due to that nasty leak thing going on, car reeks of gas all the time now. Since everythings comming out I want to replace the fuel pump as well, and while I'm at that I should go ahead and do injector and fpr upgrades as well. So, I need a little assistance just to make sure I dont burn money I dont really have to begin with.

Car specs: 92 camaro, 355ci, heads, intake, full exhaust and decent cam, CHP had a carbed version of it put down 360fwhp. Goal is an alum engine that does 450-500hp, so if the system can support that things would be good. Car currently is great at part throttle or full throttle at low rpm, but it does not continue to pull any harder a little past 3k rpm, hoping fueling will fix this. I have EBL + Autoprom running so tuning is covered.

First up is the fuel tank, looking at this one
http://www.classicone.com/wsc/catalo...8292camaro.htm
Part #4022-750-822.

Fuel pump:
Walbro 190? I heard the 255 will be too much and actually flow less because of the fuel lines being tiny. Is 190 good for 500hp?

Injectors:
I have the #55 ones currently, should I move to the #65 ones or just bump fuel pressure a little?

FPR:
I am clueless on this one, I've read people talking about welding stuff inside the tbi and then sticking an external one into the fuel lines (does it matter which line?). What should I look for in a fpr? And is there any way I could leave provisions to add a pressure gauge in the car at some point?


I was thinking of doing this in stages starting with the back of the car, but then I was confused as to what the walbro would do to the fuel pressure with the stock tbi stuff upfront still. I'm pretty much looking for a parts list, and an order of installation (stages or all at once). I've messed with some of the math required and will post up what I came up with so far later tonight. I'm hoping that maybe an excel sheet can come out of this linking the entire system together from pump to injector showing flow rates changing based on things that can be modded.

Thanks in advance!

reborn92rs

Been doing research and been modding BenP's injectorsizing.xls file to include fuel pump flow rates for the typical Walbro pumps. I think I'm done but I want to make sure of an asumption about the injectors. Do they fire in sync, as in both fire for every fuel delivery to a cylinder, or are they async? I been digging around in the EBL docs and my current view is that the injectors are in sync unless under really high load (and even then its a sign of needing bigger injectors??) Is this correct?

If it is then the walbro 190 really is sufficient for a lot of peoples needs and a 255 is way to much pump.

Dewey316

What are the cam specs? The RPM range will play a big part in fuel requirements, as the "window" of time available for the injectors to open, decreses as RPM goes up, so you may need some larger injectors if you are spinning some RPM. I would say 65 at the least, you may need more, you may be able to get away with using a VAFPR and the EBL.

I would also go 255. I have seen cars with 330-340rwhp start dropping fuel pressure, IMHO get the big pump, then down the road if you descide you want to toss a toy shot of nitrous at it, you have some extra fuel flow. The only worry is that the return side inside the TBI unit is too small, People talk about it, but I have never seen anyone actualy have a problem.

For the FPR, I honestly don't see any reason to get one, unless you are getting a vacuum based one. You may want to do that, especialy if you get big injectors (like 74#'ers). The stock one does its job, and does it just fine. If you need to bump the pressure a bit, it is easy to make it adjustable, and if you need even more pressure, TDS sells a higher rate spring. Since you have EBL though, the vacuum unit might be the way to go, it may make tuning idle a little easier, while still being able to feed the motor, especialy if you are going to spin some descent revs.

--John