TheDice951

OK, so this may end up being long but its bothering me.

i am currently working on a friends 86 951, I'm doing a trans swap... anyway, i was driving his car before i started pulling trans and his car feels tighter and smoother and the engine runs A LOT smoother and has a constant accelerating feel.... he is running the auto authority tune.

my issue, we run the same suspension set ups, and have basically the same mods except that I'm using vetesse.... my car idles better but feels like it has NO power unless the turbo is going, for instance, if am pulling out at a stop sign and want to squeel the tires a bit(not a burn out just a spirited get away) it would bog down and not really pull much at all until the turbo spools up...and the transition from no boost to boost is weird. its pulling a bit and then it feels like it looses power at 0psi and then starts pulling again when the pressure increases. he is running 14lbs and it pulls a lot harder than mine and I'm running 18lbs.... mine also back fires on up shifts and pops on down shifting. I'm wondering if a sensor is screwed up on mine or a vacuum leak but I'm not sure..... does anyone have any suggestions? I'm sure i didn't explain everything but that's the jist... the suspension is probably the bushings but mine also creeks a lot more so i think a roll bar may help mine out.... he has a harness bar? does that help?


i have replaced a crap load of sensors for previous running issues, coil, plugs, checked for boost leaks and exhaust leaks and cleaned filter and air flow sensor...

Crackership

Check your grounds. All of them. Bad grounds can cause all sorts of havok. Are you running a WB? What are your AFR's like?

Dougs951

What kind of vacuum do you pull at idle?

carlege

Second the AFR?

JohnKoaWood

18 Psi?

What turbo are you running?

TheDice951

I have a GT30R, 55lb injectors, vetesse s/w, adj FPR (FP is 3bar static)
my vacuum is between -6/7psi at idle unless it’s hot then it’s more like -9
I have a NB and it seems to be around normal but smells rich

I will look into the ground issue.....

compression is 125 across the board...

if I am accelerating you can feel it hesitating while rpms rise.

look bellow, imagine the dashes are increasing RPM from left to right, the underscores are the random blurps of hesitation. after pressure is positive it feels good besides the lack of overall power

---__------_------_---------___BOOST------------------------

Dougs951

IIRC you should be pulling alot more vacuum at idle...

and a NB is worthless imo

ehall

+1

piperporsche180944

My vac is at 18 when Im at idle.

piperporsche180944

Where are you located? Is that Johns old 951? Looks familiar :P

Lex_GTX

He said psi, not inches of mercury, 9 psi is 18 inches of mercury.

From the compression it sounds like the engine is getting a little tired. But it also sounds like tip in acceleration may not be tuned too well.

TheDice951

so -6/9psi is good?

i know NB is somewhat worthless but its not pegged to rich or lean and it fluxuates around the normal areas at certain RPMs....

i live in goldsboro NC... about 40-45min. from Raliegh NC

i have another engine sitting here that i plan on rebuilding here shortly. i just would like to fix all my major issues before i try putting a new motor in it.... thanks guys

TheLlamaGod

i would check for vacuum leak. my vac is around 14-16 idle

ehall

no. it's bad.
the NB is totally worthless. Get a WB.

333pg333

What are the specs on your turbo and do you have any dyno charts?