2+2

I had to get a testpipe installed in my 951-S due to a clogged cat or collapsed section. Now, with my KN filter element (in stock housing), 2.5" replacement exhaust, Linsey Stage 1 intercooler, LBE, I am running 2 BAR on my stock gauge. I really opened the car up this weekend and saw that the boost is at 2 BAR and more or less stays there.

Some websites say that test pipes add +0.15 BAR to totally stock cars. I guess this makes sense since 1.82+.15= 1.97 BAR.

However, I have stock chips (unless the PO put something in without telling me).

Is this too high of boost for stock chips?
My tech who races says everything is fine.
I thought that boost tapers down from 1.82 BAR a bit in stock form? (or is it taper down TO 1.82 BAR...not sure) Mine just seems to stop at 2 BAR and stay there.

Please share your knowledge....

Perry 951

I think that is too much for stock chips. I would do a dyno session with a wideband readout. This way you know that you are not lean.

FYI, the stock gauge is very inaccurate. Also, it stops at 2 bar. I ran 21psi by accident before installing a VDO boost gauge. I just kept turning up the boost thinking my wastegate was not functioning right. I wanted to be a little over 2 bar on the gauge (about 16psi).

Get a boost gauge and do a dyno run to be sure.

2+2

In this regard, why would it boost over the 1.86 since I have the stock wastegate setup and my LBE is also in stock position? Yeah I have heard that these gauges are pretty inaccurate....
Also, I have some minor backfire when I release the accelerator in very minor part throttle....Is this normal with a test pipe?

Perry 951

Yea.. it is normal to hear some pops with a test pipe. It is typically not a backfire but more a backpressure pop.

If you have done nothing to the boost limiting equipment (banjo bolt, MBC, drilled or disconnected cycling valve), you should be at the .85 bar that is factory. Your wastegate may not be functonal, or the gauge is way off, either way, you should get a boost gauge.

2+2

Thanks Perry..more toys to buy....good luck on your rebuild..

2+2

Perry or anyone, how hard is it to install one of those lean/stoich/rich meters? I searched and it appears that a boost guage is relatively easy by running a T from the computer in the floor board. What about the fuel ratio meter? Do I have lift the car and drill into the exhaust? Or is it something that is significantly involved?

Thanks.

Duke

It's very easy to hook up an A/F-meter, you can pick up the signal from the O2-sensor going to the computer (located under the passenger side foot area).

Take a look at 951 RacerX's website!
<a href="http://members.rennlist.org/951_racerx/ARM1install.html" target="_blank">http://members.rennlist.org/951_racerx/ARM1install.html</a>

Hope it helps
Gustaf

kasturbo

The a/f meter that I bought from Lindsey's came with easy follow installation instructions. Took me about 20 minutes.

2+2

thanks!

2+2

Well, I took out my car this weekend for another test...but this time, I took my wife with me to keep an eye on my boost gauge and to report on what she found.

I am happy to report that everything seems normal in that my boost pegs at 2 bar, but after about 4 seconds of that, it does go down to about 1.85 bar or so.....which I believe is normal.

It looks like when I was testing it on my own, I didn't stay on full boost long enough. I was going too fast and had to keep my eyes on the road.... Thanks for your replies guys.