The winter blues have set in so it's time to upgrade! Right now I am running AA StgII chips and reliaboost @15psi. I also have a 3" cat-back.

My question is, which upgrade will I see the most gains with, Guru chips or the test-pipe? I hope to eventually do both.

 

I went from AAStgII chips and MBC set at 15psi and added a 3"exhaust and testpipe with a lightweight flywheel.

255rwhp and 300rwtq. Guru chips would probably clean up the rich midrange and possibly give me a nice kick in the pants between 3000-4500rpm but I don't know that I'd see higher peak hp.

 

Hugh-
Nice numbers for an '86! I didn't see anything on your website about fuel controllers. How did you adjust the a/f ratio?
Thanks!

 

Replacing the stock cat will help (less back pressure, quicker spoolup). Also if you have been running AA chips, they tend to run rich, so your cat might be clogged or bad by now.

A test pipe is a good base that you will need for more performance mods.
After that, clean up your AFR either with new chips or a PiggyBack.

 

-oops-

 

boostaholic:

I have a very restrictive turbo, so I didnt notice anything when switching to a test pipe.
I also didnt notice a huge change when moving from the stage 2 chips to Guru, except the guru
chips have a waaay better curve, and spool faster.

ninefiveone:

That curve looks exactly like my curve did when I had those chips in, and, yes, the guru chips fixed it for me also.
I'm not sure how much it takes to wash the cylinder walls, but I wouldnt run it like that for longer than necessary.

 

For me personally, the test pipe was the "missing link" to all my performance mods. Not that I have a lot; I'm running the typical bolt on drop in stuff. BUT...when the test pipe went on, I was AMAZED at the responsiveness of the car; it really spooled more quickly. And, as a bonus, you can really hear the turbo spool up...I did a dyno run after the test pipe, and the gains were minimal. Seat of the pants, however, is another story...

 

Thanks for the feedback everyone. I was leaning towards the test pipe but I wanted to get confirmation.

ninefiveone: those are impressive numbers, I bet you can find another 5-10HP with a cleaner a/f curve. Were you running race gas at 18psi?

 

There's no fuel controller on my car. This is engine tuning cave man style. I turned up the boost until the A/F wasn't so rich in the upper revs. I'm sure there are gains to be had if the curve was better but for now I've got other issues that need to be attended to.

I've been running these chips at 15psi for 3 years on the track without the testpipe and exhaust. The last time I had the head off the pistons showed that I was running a bit rich but everything else was up to spec. In the end, I'm not WOT in the midrange all that often. At the track I'm usually 4000 rpm and up.

I'm running pump gas. 93 octane from whatever gas station I happened to be near when I filled the tank.

 

Are you still running with stock WG with original springs? If so I'd strongly recommend some upgrades with them.

 

Compare the HP differences between the US-spec. car and the Euro one without cat. There's a 3hp difference. Over time, the cat can get clogged and rob you of power. This can be a drop of anywhere from -5 to -15hp. So, putting in a cat-bypass pipe will get you back to stock+3hp. Does anyone have before & after comparison of a cat-bypass upgrade?

Typical upgrade from APE chips to GURU sees a gain of +20hp (+50 over stock). Even more importantly, the low-end/partial-throttle mid-range is significantly improved (doesn't have that super-rich mixture like dyno above).

"I also didnt notice a huge change when moving from the stage 2 chips to Guru, except the guru chips have a waaay better curve, and spool faster."

Yeah, +20hp isn't really that obvious to the SOP-seat of the pants dyno. Want to try our latest 18psi chip? heh, heh..



BTW - GPR has a great deal on the Bursch test-pipe, about $220 or so .

 

Danno, I picked up about 5 horse and 5 tq; however, I ran on two different dynos on different days so that could actually account for that...

 

So Danno, is my dyno chart enough for you to burn a set of chips for me? Or would your latest 18psi chip be enough?

 

233RWHP 238RWTQ stock 951S with free flow 3'' exhaust, 0,8BAR.
My dyno

Danno have you sent out my chips?

Fredis