ebs

I had been running my car with LBE set at 10 psi as I was of the impression I had chips. After a couple of years of running the car this way (it was done byy the previous owner - an idiot) in making inquiries into the type of chips, I found they were stock! I turned the LBE to 5 and then decided to order some chips from Guru as the car was now quite a bit slower. Hopefully using LBE at 10 without chips didn't damage anything.

I had my mechanic install them today and what a difference! I have continued to use LBE and already had high pressure fuel regulator. Also went for one range colder spark plugs. To be on the safe side I planned on setting them up for 15 psi (instead of 18). We connected an external boost gauge and foudn we topped out at 13.5psi. My mechanic suggested leaving it there to be on the safe side and he felt from experience from ra.cing 951s that the stock turbo is maxed out around that point. Any thoughts on this?

Using lower boost couldn't damage anything or be bad in anyway if the chips are set for 15, right? (I am using map 1 which can handle up to 18 psi).

Now the turbo spools up much quicker and the car pulls harder throughout the rev range. In 5th gear at 60 mph, the pick up is significant compared to before - can really hear and feel the turbo. I have a straight through 2.5inch stainless exhaust (no cat and only a small muffler) and when I back off there is quite a bit of popping from the exhaust, which my mechanic seemed fine with. Overall I am impressed with the performance gain and haven't even installed shims!

jimbo1111

Stock boost is close to 11 psi. So you were not in any danger because you never exceeded that.

hosrom_951

If the chips are made for 15 or 18psi running lower boost (14psi for chips mapped at 15psi) you would be running rich. If you run higher boost (17psi when chips are mapped for 18psi) you would be running lean....

I suggest you contact GURU Racing to dertermin what are you're chips mapped for exactly to run them safely....

ebs

What are the issues with running rich?

I know lean can be very dangerous, but how about running rich? At idle there is no smoke - car runs clean. Do you think the popping I hear when I ease off the accelerator is because its running rich?

Mike1982

When you run rich, you lose lots of power plus you are burning up way to gas. I would see what Guru says the chips are for, what boost, then set the boost there. He isn't pushing the car into the lean side, so you don't have to worry and if you want, you can always run -.5 or even -1.0 psi less if you are so worried, but you should notice a HUGE difference when you get the air/fuel ratio close to what it should be!

ebs

Thanks MIke 1982 for your reply.

Besides more fuel and less power, can it harm the engine?

WesM951

IIRC the turbos on our cars have diminising returns after 18psi. If your only getting 13.5psi, I would check your wasegate and shim it.

ebs

The 13.5 was deliberate on my mechanics advice. The quetsion being, will it now run too rich, and can that harm the engine in anyway?

hosrom_951

ebs: As i mentioned, as GURU if the chips are mapped for 15psi or 18psi and set it to either one to be on the safe side (but Mike also mentioned how more/less boost if effected, better running slightly rich than slightly lean )

HD911

It will run very rich if your chips are mean't for 18psi and a little rich if they are mean't for 15psi although 1.5 psi won't harm your engine, it may cause some issues over the long term.
If you are happy with 13.5 psi then leave it but 15 psi is even better and shouldn't be a problem.The popping sound you hear seem's to be a semi-common issue with some of the Guru chips.
If your chips are meant for 18 psi then I would run at least 16.5 psi , otherwise you will be way to fat.

Good luck

ebs

Thanks HD 911. I had my mechanic set up for 15 psi initially using the setting of map 1. SO we may be about 1.5 psi too low. What sort of long term issues are you referring to please?

HD911

Running a LITTLE rich isn't going to harm your engine but it won't be running optimally, and will get bad gas mileage, foul plugs, etc, get a wideband air/fuel meter and know exactly how fat or lean your engine is running!

hosrom_951

ebs: Are you getting lots of exhaust popping noises or just occasionally?

Running slightly rich combined with no CAT or primary muffler is normal (i get that on stock chips no-CAT occasionally).

sweanders

If you are running to rich you will wash the oil off the cylinder walls.. Not very ideal..

evil 944t

I might be going out on a limb here but,

1. if the chips are set up for 15 and 18 psi, do it.
2. buy a a/f guage
3. If 13.psi is what you want to run, Try putting your stock FPR back in. This will lean it up a bit (10%) I believe.