Fuel Pressure and Performance

[stevebz06]

I have a 2001 Z06 that I am trying to squeeze a bit more performance from. I have checked fuel pressure at the fuel rail with two different pressure testers and come up with about 55 PSI (averaging the two readings, they differ by only a few pounds). The factory manual specifies 55-62 PSI. That puts me right at the bottom of the acceptable range, and I HAVE changed the fuel filter recently.

Does anybody have an opinion or experience as to what an increase in fuel pressure would do to wake up the engine? The fuel pump, in addition, has been very noisy, so I'm thinking it might be time for a change.

[c4c5specialist]

HI there,

You are still in the acceptable range.

However, I would be more questioning the VOLUME of what you are seeing, NOT just the pressure.

That being said, performance is a combination of many things.

Do you use top tier fuels?? Have you put any Techron in the gas tank recently?? Any BG 44K ????

Allthebest, c4c5

[stevebz06]

I had the same thought about volume. Is there a simple test I can perform to check that? I have used mostly Shell lately. I believe that is a top tier fuel. I haven't been very consistent on using Techron, but I plan to become more so in the future.

I plan on getting the car on a dyno but before I do, I want to make sure it is performing as well as I can expect it to. With the old L98's, I remember people fiddeling with fuel pressure trying to extract a little more power, that is why I was focusing on that. The car seems to be running well, but I've been losing to cars that I used to beat easily, lately. I'm just trying to see if I can get anything more out of this car before I give up and start looking for something else.

[c4c5specialist]

HI there,

Well, a few things that I would recommend.

#1, check to see if you have all the latest programming updates from GM for the PCM. They do change from time to time and its critical to make sure you are current.

#2, Shell fuel is top tier so the need for Techron is reduced. That is very good. 44K is a decarbonizer and I would recommend that simply as another way to help your engine reduce ignition retard to carbon build up and spark knock.

Also, checking the fuel trim tables to make sure the computer is not adding or taking away too much fuel.

Let us know how you make out.

Allthebest, c4c5

[stevebz06]

Just one more question: should I avoid mixing both the Texron and the BG-44K together or does it matter? The car doesn't get driven much, so it may take awhile before I put more gas in it.

OK, actually two questions: I don't think I've ever had a computer update. I've had the since December, 2000. So you think I might be losing something that could slow me down?

[LLC5]

Originally Posted by stevebz06

Just one more question: should I avoid mixing both the Texron and the BG-44K together or does it matter? The car doesn't get driven much, so it may take awhile before I put more gas in it.

OK, actually two questions: I don't think I've ever had a computer update. I've had the since December, 2000. So you think I might be losing something that could slow me down?

I wouldn't mix Techron and BG44K together if you have a choice not to. Run each seperately through a full to empty cycle without diluting the mixtures.


If you haven't had an update since 2000, then you probably could use one. There was a calibration for updated spark plugs that you may not have. You could probably give your local dealer your VIN number and have them run it to see if you need any updates. Good luck with it.

[c4c5specialist]

HI there,
Larry bring up an interesting point, as the revised spark plugs are ACDelco, 41-110 IRIDIUM tipped plugs.

Do not regap and torque to 15 ft lbs. Gap is preset to .040.

Allthebest, c4c5

[stevebz06]

I went through that when I installed those plugs. I regapped them to .060 ", found out that I had made a mistake, pulled them out and gapped them to .040 ", found that the engine ran worse. I decided that I'd try E3 plugs, and right now I'm happy with those.

[markw8]

Apparently when they are regapped it can damadge the irdium coating. You did this twice.

Mark

[c4c5specialist]

HI there,

How do you classify 'ran worse' ??

Allthebest, c4c5