Suggestions wanted - 930 engine low on power

[rotorhead]

Hi guys,

I'm throwing this out to the forum as I am stumped and frankly I don't know where to go next. Maybe some enlightened expert like PorschePHD, DonE, RarelyL8, beepbeep, Wayne, John Walker etc etc may be able to give me a clue.

This will be a long post to try and cover it all; but here goes..

I bought the car in 2003 in the Middle East and brought it home with me in 2004. It was always a poor performer for a Turbo.

2005 - Top end rebuild (Mainly due to oil leak at cylinder base)

• New Rings
• Steel Headstuds
• New K27-7200 Turbo
• Air injection Delete
• AC Delete

Still having low power issues
2005 - Fuel system

• 6x new injectors
• new Accumulator + Filter
• 2x New Fuel Pumps
• New Ignition Coil
• Magnecore Wires

Put the veicle on a Dyno to establish a baseline. It made a measley 113kw see here Dyno results - my 930 Sucks!
Pulled the engine and rechecked Cam Timing and did a leakdown at 4%-6% across all acylinders. Was leaning out under boost so I probably wrongly assumed the Fuel distributer was the problem. So I ditched it with a...

2006 EFI Upgrade

• Goingsuperfast EFI Kit
• 60lb Injectors
• Wasted Spark EDIS
• EMS Stinger Programmable ECU
• LC1 Wideband O2
• Performance Exhaust
• RartelyL8 Style Intake Filter

2007 Injectors blocked due to corrosion in fuel tank

• Reconditioned Fuel Tank
• New Fuel Pumps
• Injector Service

back on the Dyno - only 140kw (Stock is 220kw)
There is no problem getting enough fuel to the engine... had to lean it out under boost. I am still running stock boost.

I guess I am at the point where I have now replaced the Air/Fuel and Spark delivery systems to the engine.

This car is turning into a real garage queen.

[David]

I assume it's not just the dyno, but also feels slow on the road.

Since it's EFI, I also assume it was tuned on the dyno meaning your air fuel ratios and ignition timing are set correctly. Does your injector duty cycle match the HP you're making. If so, you're not getting enough air into and out of the engine. Are there any restrictions on the intake or exhaust?

It's unlikely but perhaps it's friction. Does the engine turn over easily by hand? Do the wheels and transmission turn easily by hand?

This has got to be solvable. Keep feeding us info.

[rotorhead]

I really really hope its not friction. The car feels sluggish It has 5000km since the rebuild

I'll pull the plugs and turn it over..

[NathanUK]

You didn't mention any change of IC.

Just a thought, (none of your poll suggestions) but have you checked your intercooler for debris? eg a rag or paper towel.

Try hooking up a mechanical boost gauge to the actual inlet manifold itself and see what boost pressure you are getting after the TB.

[rotorhead]

Great suggestion... I'll do that and get back to you.

[rotorhead]

Intercooler is fine - Unfortunately

I'll hook up the boost guage tomorrow


Steve

[David]

This is such a huge power loss that this has to be something major and therefore obvious... I think. So don't be offended by questions that seem rather obvious .

When the top end was apart and the intake and exhaust off, did you find anything strange?

If everything seems mechanically correct and there are no restrictions in or out of the engine, I'm leaning toward cam or ignition timing issue. Are your spark plugs all the same color? I had different color plug readings left to right and turned out to be the cam timing was off. Have you checked ignition timing with a timing light?

How about some pictures of the engine in case that brings up any questions.

[dean]

I would guess you aren't running any boost.

[rotorhead]

Originally Posted by 125shifter

This is such a huge power loss that this has to be something major and therefore obvious... I think. So don't be offended by questions that seem rather obvious .

When the top end was apart and the intake and exhaust off, did you find anything strange?

If everything seems mechanically correct and there are no restrictions in or out of the engine, I'm leaning toward cam or ignition timing issue. Are your spark plugs all the same color? I had different color plug readings left to right and turned out to be the cam timing was off. Have you checked ignition timing with a timing light?

How about some pictures of the engine in case that brings up any questions.

David I totally agree with you...
There is something very significant wrong..

I have attached some photos from my phone. The intercooler was off checking for obstructions.

My mechanic said he verified the ignition timing with a light to what was being setup in the ECU. Last Friday (3 days ago) he said that he pulled the plugs and they were the same color. The reason why I have had the car at a shop is that I have passed my level of competance with this vehicle.

I have now just booked the car in with a shop that specialized these vehicles on thursday I am taking it 600mi to get checked out.

[rotorhead]

Originally Posted by dean

I would guess you aren't running any boost.

I wish that was the case. It shows .8bar on the cockpit gauge and the wastegate pipe spews flames at full boost. It looks like a bunsen burner at WOT

here is a video of a run on the dyno

09112007.mp4

[rotorhead]

Originally Posted by 125shifter

When the top end was apart and the intake and exhaust off, did you find anything strange?

In all honesty the only starnge thing I found was that the rocker shafts walked after I had torqued the to the factory settings. I had to increase the torque and put rsr seals on them.

[Oh Haha]

Here's a thought:

wcc(Bill) has an 87 930 that didn;t seem to be putting out all of the power,either. After replacing the boost spring and the exhaust with a GHL muffler, the car is a freakin' rocket.

The only thing we can figure is that the cat. converter was clogged ,at least partially. It was removed when the GHL was installed. He has headers but they are not installed yet.

The dash guage read .8bar just like yours and you could hear the wastagate working.

It's a longshot but you may want to have the tech check it out. If you need your cat for emissions you may need a better/new one.

[David]

Can you look inside the intercooler with a mirror or camera and confirm that there's no blockage on the core?

[RarlyL8]

I wish that was the case. It shows .8bar on the cockpit gauge and the wastegate pipe spews flames at full boost. It looks like a bunsen burner at WOT

That should not happen. The exhaust system in that area should not be hot enough to ignite unburned fuel which means it is likely burning out of the exhaust ports. If you can take for granted that the A/F ratios are correct this condition suggests the engine is under a terrific load. If not it is mimicing that condition, possibly through timing or fueling issues.

You have done all of these radical changes and still have the same problem of low power?
Is anything getting excessively hot during operation? How about your transmission?
Way out-there question but how much does the car wiegh?
What exhaust system does it currently have? Cat?

[930gt-40r]

+1 on what Rarlyl8 says. I have never seen a wastegate blow flames for any length of time.

[spuggy]

Um guys? they don't blow flameballs all the time, but they do emit a continuous stream of hot gas whilst on boost that borders on a flame - it will certainly burn a epoxy-treated floor in the dyno room. (which makes a fair amount of stinky smoke BTW, hard to miss when you think it's your car burning up).

My $15 Ebay SS dump pipe goes straight from the flange and then angles down at about 45 degrees - we slash cut it level with the bottom of the H/Es. The circled mark by the rollers wasn't left by that rather nice longhood:



On a long-ish power run, the headers glowed orange-yellow all the way up to the turbo and the wastegate, and the far end of the factory muffler can melted license plate wires 6-8" away inside the bumper cap. And that was when it was a little rich.

I forget who the 965 pilot was who posted his track flyby video here a while ago, but he certainly demonstrated that they do puff flameballs from the wastegate on a shift if they're hot enough..

[spuggy]

Originally Posted by rotorhead

I wish that was the case. It shows .8bar on the cockpit gauge and the wastegate pipe spews flames at full boost. It looks like a bunsen burner at WOT

here is a video of a run on the dyno

09112007.mp4

Err, no flames visible on the video?

Hard to tell, but the exhaust does sound kind of muted - I think Oh Haha had a good suggestion - do you have a cat fitted? Is it the type of factory exhaust that routes the wastegate into the muffler as well?

Have you tried fitting an open pipe for testing purposes? Just something to route away from the bodywork would do.

Was that really full throttle? You've checked the throttle plate moves all the way, right?

I'm with the "it has to be something pretty major" group. If you hadn't said all the plugs looked the same, I'd have suggested you check the firing order.... I mean, EFI is supposed to be worth what, about 100 HP on it's own?

[9dreizig]

E brake on ?? ( just kidding) First thing I'd do is dump the CAT ..

[rotorhead]

These suggestions are a great guys. I'll check them all out today. Although you cannot see the flames on the video there was definately a faint blue flame coming from the wastegate dump pipe at the time the video was taken.

The current exhaust system is a straight through aftermarket muffler (you could almost roll a tennis ball through it)

I checked inside the intercooler with a mirror and unfortunately it looked clear. I have checked the throttle plate movement.

I have the car back in the shop this morning.. i'll get them to pull the plugs again.

I appreciate the effort you guys are going to to help.

[rotorhead]

PS. the car doesn't have a cat