Carrera 3.2 fuel pressure?

[scarceller]

Hi,

I'm trying to sort through a 84 Carrera 3.2L I purchased and have noticed something strange with this car. I was setting idle and CO and just looking over the fuel delivery system when I found my Fuel pressure to be 3bar at idle with vacuum line connected to the regulator and 3.5bar with it disconnected. This is 1 bar higher than stock spec (2 and 2.5bar), so I decided to remove the requlator to see what I have, it is Bosch Part #0280.160.215 and has no other porsche number on it. From a few searches it seems to be for a 928? Any idea what I have here? and is it really a regulator speced at 3bar?

So, why does the car run OK? The Prior Owner had much work done on this car. Web 20/21 cams, port and polished intake, SSIs 2 in 2 out M&K muffler. He also had Steve Wong create a custom chip from a dyno run and Steve found he had to lean the mixture a lot. Of course this makes perfect sence now since the FP is 1 bar higher than stock. I spoke to Steve about this and he remembered the car and having to lean the fuel maps but was un-aware that it had 3 to 3.5bar FP.

So, I'm left wondering what exactly are the specs for the Bosch FP requlator I have? (0280.160.215)

Was the FP incresed intentionally? or is the regulator out of whack? In either case I'm not sure what to do, but I'm happy with the Steve Wong chip as is and the car has good AF Ratios across the RPM range so it runs fine. However, do I need to worry about a FP this high?

Thoughts?

Thanks in advance.

[jbrinkley]

if it aint broke?

[scarceller]

Originally Posted by jbrinkley

if it aint broke?

I agree, it ain't broke. But it also is far outside of factory spec which has me a little concerned. But it does run well.

[sjf911]

The OEM injectors were probably maxed out with the engine changes so it sounds like they chose to increase fuel pressure rather than change injector sizes.

[scarceller]

Originally Posted by sjf911

The OEM injectors were probably maxed out with the engine changes so it sounds like they chose to increase fuel pressure rather than change injector sizes.

Steve, thanks. I suspect you may be correct but at the sametime Steve Wong found himself having to really lean out the AFR maps so this means they may have overdone the FP increase.

Also, I have now determined that the Bosch FP requlator part # 0280.160.215 appearse to be the correct one for the Carrera 3.2L as well. So this means someone somehow increased the fuel pressure on this part by 1 bar to 3-3.5bar. Could this actually be accomplished? Or is the FP Requlator just somehow out of tolerance?

[sjf911]

I don't know how you would get a consistent increase in pressure with a stock FPR unless there was an outflow restriction or it was faulty from the factory. Unfortunately, at this point if you replace it you will have to have your chip remapped.

[scarceller]

Originally Posted by sjf911

I don't know how you would get a consistent increase in pressure with a stock FPR unless there was an outflow restriction or it was faulty from the factory. Unfortunately, at this point if you replace it you will have to have your chip remapped.

That was my thought as well, if I ever need to replace it I could also put in an adjustable requlator, I guess.

I have insured I have no restriction in the return line to the tank.

Thanks.

[scarceller]

I have learned that it is possible to muck with the stock Fuel Pressure requlator and actually increase the fuel pressure from the stock 2bar.

I have been told that you can squeze the top of the requlator in a vise and actually cause the FP to increase by squezing down the cap/top of the regulator. The part that gets squezed down is the part that the vacuum line is connected to.

I guess you better get it right the first time. Will need to look at my FP Requlator again to see if I can spot any signs of this alteration.