jasoncoker

Hello All,

I thought I would share my dyno results and get some feedback.
So, I got some chips and the car ran great at 18lbs. Then, I started hearing a little pinging in the midrange so I tried to stay off-boost. Ultimately, the headgasket with 100k miles on it blew.
I put in a widefire HG, new belts, new H20 pump, etc. This is what is on the car presently:
GHL 3" catback
Bursch testpipe
Ceramic Accuboost
CV delete
Tial 38mm with .8 spring
New cap, rotor, plug wires
Cleaned and balanced stock injectors (injector harnesses seem pliable)
NGK Iridium plugs 1 range colder
3bar FPR
The car runs great now, but as you can see from the dyno, it is lean. The chips were mapped for a car with a stock wastegate and exhaust. There is no pinging, though. I am now staying off boost just to be safe.
The car is an '89 Turbo. Vacuum is about 14-15 at startup and stabilizes at about 17 when warm. The first 3 runs are at 18psi and the last is at 15psi. I am considering changing the chips, but others with the same chipset are running up to 20lbs and even more with H20 injection on them. The first two runs have a more stable A:F ratio--maybe b/c the car was recently started and still in enrichment mode? It was warmed up, though.
Thank you for the feedback.
Sincerely,
j

special tool

You will be doing the headgasket again if you continue to run 18 psi. Multiple dyno runs with 15:1 AFR at torque peak is a huge no-no.

You will need chips and a raised fuel pressure with your current pump and injectors to run 18 psi.

Mike B

What brand of chips...and is the turbo stock?

Ski

The gain in hp over the two runs is not worth the $$ it will cost to repair your engine if you blow the HG IF piston and wall make contact from the water getting into the combustion chamber. Take tool's advice or stick the 15 psi, 268/318 which is a nice run with a stock turbo! Shows you what a good A/F can do for you. But, for 4hp and 2lbs of torque, 18 just isn't worth it.

jasoncoker

Thanks for the feedback, guys.

Ski, The pics are out of order, so the 15psi run is #4 on the sheet which is 262/291. That run is just as lean as the 18lb runs @ tq peak, better at hp peak, but even leaner thereafter.

Special, the car already has a 3 bar FPR.

I have the mbc set as low as it will go and am staying out of the boost until I get this resolved.

Mike, the car has a stock turbo and I would rather not say what the chips are so as not to impugn anyone until I find out what's up.

More feedback please! Thank you.

Evan70

I honestly don't see how any 88S/89 can run more than 16-17psi with stock injectors. My car with just a DP wastegate, EBC and testpipe and Guru chips was running 13:1 at 16psi. I haven't been back since switching to Vitesse chips and getting head work done (blew the headgasket on the way home from the last dyno session), but the Rennbay narrowband A/F gauge shows the same at 16psi with the Vitesse chips as with the Guru. At this point, I'm gonig to have to go to 55lb injectors before doing any more mods or raising the boost further.

njim3

Hi,

I would like someone here to show me how to read the A/F ratio. I got my dyno last time but i don't know what number is rich with is lean.

Thank you,
Jim

lart951

the optimal a/f ratio at high rpm's is 12:1 - 12:3 anything over 12:5 is lean, your mid range while you are building boost is okay @ 13:1- 13:5 and idle 14:7. But don't listen to me I use a lot of drugs mixed with alcohol.

ehall

"don't listen to me I use a lot of drugs mixed with alcohol."

You're supposed to say "Hi. My name is Luis" before saying the other stuff. Are you off the wagon, or did you just forget.

Listen to these guys about the lean issue. They know what they're talking about.

lart951

Thanks ehall I had forgatten my name. Hi my Name is siuL welcome to Rennlist.

ehall

the guys at the meetings will be much happier now.