mark kibort

what a hot mess of a car. runs like crap, doesnt start after warm, smells like fuel out the tail pipe after it does start, feels like the valve timing is off, but that could be due to the dual exhaust, no cat and no real mufflers, so its loud.
slight pinging under load, but its very slight. i wouldnt take this thing above 4krpm because it doesn sound healthy, but when it idles, it idles very smooth.
not the ecu, because we plugged in the GT compter and it didnt change anything.
has 30lb injectors, which might be the issue. Ill due a fuel pressure check next week to see what is really going on. probably check the valve timing too, just because it sure feels like somethings not right.

driving on the street. my race car is far more damped and well mannered on the street. this thing wonders and bounces all over the place. seriosly, if it wasnt for the big bumps in the road that the race car doesnt handle, the over all handling and ride is much better with my race car when im driving to the track, loaded. up. or even around town.

its almost like the car has too much bump, and no rebound.

very nice driving a street 928 for the noise, and comfort, but it really drives like crap. wondering if anyone elses street 928 with the aftermarket suspension drives like this too. if the shocks and springs are supposed to be right for the street car, someone got the settings way off!

so many other things to mention, but its going to be a project to help get this car into shape.

Rob Edwards

Has it been sharktuned? If you can hear pinging, you're killing it.

Mike Simard

What is this car? Just bolting on parts is only a step, time must be spent on each area to ensure success.
The way you describe the suspension as "wandering" could be something other than the shocks or springs. Assuming the same level of finishing detail has gone into the suspension as has gone into the motor, you could even have loose parts.

White Lightnin'

You've got 2 issues going on here in this thread: engine & suspension.

I can address the suspension, since I have the same combo on my street 928... they are great!

However, you still need the 4-wheel alignment at regular intervals (6-12 months), ride height adjustment and 4-corner balancing for the suspension to do what it is supposed to do. Remember also, low profile tires on 18" wheels will make you 'feel' the road moreso than those on 16" or 17" wheels with taller sidewalls.

Stiffer sway bars couldn't hurt either.

But then, you know all this right?

Mongo

I think it's begging for a sharktune. The fact that it has 30 lb injectors and an untune LH could be fooling the software and causing to lean out too much.

andy-gts

eibach\bilstein set up was way too harsh for this old man!

dr bob

Mark--

If this car is new to you, the drill is well-known:

-- New oil and filter. Gets all the fuel out of the crankcase.

-- New plugs. You get to look at the old ones and see how they were firing.

-- Compression check. No use chasing tuning if the cylinders aren't holding pressure.

-- Inspect caps/rotors/wires. Replace as necessary.

-- New oxy sensor.

-- Plug in a Hammer or similar and read the diagnostics from the controllers if this is a '89+ car.

Then, you get to swap in known-good MAF. You get to VERIFY cam timing and inspect and tension the timing belt at the same time. Make sure the tensioner has oil and doesn't leak.


Since you have a similar motor sitting in the other car, you can swap critical pieces easily with minimal expense.

mark kibort

I've done this a few times
alwaysbthe same car
My race car didn't have an alignment for 8 years no issues and drives like a dream
Ask bill ball

The suspension was eibach bilstien and scots was this set up, my 84 was this set up and worked well
The engine is devek and this one never seemed to run right

My stroker has 30 lbers and is pretty good with no tuning and fuel pressure backed off to 44 lbs and still Rich but runs great
(11.5:1 fuel air at worst)

I'm suspecting bad timing
Something major

This is not my car but a friends that I said I would take a look at it

dcrasta

Dumping fuel out of the exhaust? Needs a tune in a bad way before you end up doing damage to the bearings or cylinder bore/rings.

Dr. Bob's list seems spot on. Maybe you can go through the initial diagnostics and report back with some hard data.

IcemanG17

I also don't like the bilstein-eibach combo on street 928's....I call it "cloppitty"...but the cut eibachs-bilsteins on the Estate are GREAT on track

Which stroker is this?

brutus

Have to ask who built it and what is the compression ratio ? Running it that fat might be to mask detination issues from all that stroke with a 100 mm piston. The GTS tends to be on the ragged edge with less stroke.
What pistons are in the block ? Many of the early experimental engines have had basic design flaws that were not well understood at the time. Like poor piston design and coatings, offset connecting rods, questionable cylinder preparation, so put on your CSI hat and start digging.

jetrainor

I have had the bilstein/eibach setup for several years.....DE's but mostly street and love it.....235/275 front/rear 17inch tires.

Hilton

If its not your car, be careful how far you go with it.. a poorly-running-much-money stroker is a minefield (this car's been discussed here a few times).

Firstly - is it running GTS chips? Or 5.0 ones? (or worse, Autothority ones?)

After answering that, time to plug it into a sharktuner - for the ability to watch spark retard values and see whether the knock sensors and hall effect sender are working, as well as see whether its detecting knocks on any particular cylinders. Ignore the tuning issue - but that's the owner's problem, not yours, although putting a WBO2 on it allows setup of the adjustable-FPR at least.

Or - just explain to the owner that getting this car sorted properly/professionally will cost $15k (likely - between labour to R&R engine management systems, and tuning/dyno time), and offer him $12k less than the asking.

Then you'll have a street 928 like your recent post wishing for such, and a stroker one no less, albeit one you'll need to spend some time on to make it work (the $15k doesn't go away - it's just ameliorated by your own abilities and time). And he'll get more than its reasonably worth to a non-DIYer, as well as be relieved of the headache this is causing him

mark kibort

Hilton!! Great idea!!

GregBBRD

I know that I'm in the minority....but I think that these things with the Eibach springs and Bilsteins drive like 1 Ton Chevy Dually pick-up trucks and completely ruin the vehicles.

Not only are they way too stiff, they handle like crap...the stiffness jars the car over the slightest bump, disturbing any slip angle one might be establishing.

I personally wouldn't drive one to the junk yard with this combination...I'd have it towed.

Other than that, I have no opinion.