2years + for a turbo install runs crappy need help!
 

Long f'n story, :mad:
I took my 77 targa to my lpm to have oem 930 take off turbo installed.
It has a 3.0L in it that ran tits prior to turbi install.
My mechanic finally tuned it back to me but it cuts boost at 10psi and the whole car acts lke it has a fuel prob., sputtering and lagging,plus the temp is 210 plus on a 50 degree day.
He's made up a million stories as to why he can't get it to run right post a 3k build/ransom bill.
To add insult to injury, he dropped a jack on the right rear qtr. panel.
I'm no Porsche mechanic, but know my way around marine big blocks pretty well, I own and operate a Parasail business and do most of the maint on the powerplants.
I really need help guys! Been with out my baby for over two years and am petrified to drive it due to issues.
I'm post divorce and tired of my ass hurting all the time.
Please give me a place to start.
Thanks,
Sam

Pictures would help so we know what kind of install your mechanic did. No two are the same...
Cutting boost at 10 psi is normal for a non-turbo car. If you went much higher, you would be sorry.
This may be a fuel starvation problem. The manual calls for a certain amount of fuel to flow in 30 seconds I think it is 51 ounces (1500cc). If you get that much, flow is good.
Then I would look for a lean condition, that could also be contributing to your running hot.

$3,000 for a turbo is about right, depending on how many parts were included. Do you have an intercooler?

Mark

Give all the details and we would be glad to help. $3000 for a turbo install including parts is a steal in my parts, maybe you just need the finishing touches to make everything ok.

Sam,

You're really not gonna get very valuable help until you help us help you. Post a full description of

a) What you started with

b) What was changed/fitted/done

c) What you have now.

Even your sig says it's a 77 targa, but you now have a forced induction 3.0. Was that a 3.0 Carrera? An SC transplant? A 3.0 930?

What compression ratio? What turbo? What injection system? What ignition? What's the 411?

Mark's right - 10 PSI could be way too much boost for a high C/R motor - like an SC, for example. What's it supposed to be set to boost to? Is there an overboost sensor in place?

Frankly, I wouldn't even run it into boost until you know what's going on.

Seems to me you have at least two different car-related problems. The overheating could be ignition related, the sputtering sounds like AFR/mixture related and the idle sounds like a leak.

What oil cooling do you have? Fender mount carrera? Trombone? Front mount? Engine oil cooler only? Does it run hot if you're not in boost at all? How do the plugs look? Running lean (air leak) will also make it run hot, even off boost.

I don't think you can get away with no external oil coolers if boost is involved, even on a cold day.

When you say it sputters - when? All the time? Just on boost? Only when cold? I'd incline towards "massively lean from air leak" if it were the first. Which might also explain overheating. Heck, mine sputters badly pulling away cold with too much throttle as soon as the weather gets cold until I adjust the idle mixture to get CO2 in the right range. Then it runs too rich in the spring.

As far as a $3K bill from the shop goes, that doesn't go very far at a good independent Porsche shop. And not all independent Porsche shops are the same. Folks who work on factory 930's aren't necessarily qualified to work on modified 930's or custom installs.

Just for information, my factory single '77 fuel pump supported a mild 930 install for 310 FWHP just fine. But you should baseline the fuel flow, along with everything else.

Sounds to me as though you're either going to have to do it yourself, pay your mechanic an hourly rate to sort it, or get another mechanic (and pay them).

Thanks
 

Thanks for the quick replys,
The motor is a 79 3.0 L carerra motor. Looking for 40 or 50 hp increase from stock- maybe 230 or 250 @ the flywheel? Nothing crazy, just some Turbo punch.
The turbo and headers were pre-purchased by me, the 3k was for install and sorting it out only, which never happened completely even after 2+ years in the shop!
The power loss/sputtering happens when the wastegate opens at @ 10psi.
she runs @ 210 when cruising down the highway at 70mph in 50 degree weather.
My cooler is in the pass. front fender well and is the updated carerra type, not a trombone style. No aux thermostatically controlled fans though.
No inter-cooler, aav and csv removed to make it idle down close to norm.
I will include pics tomorrow, please keep the questions and help coming, I need them desperately!
Pics tomorrow and thanks again!
Sam

Spark plug type and gap?

Narrow the spark plug gap, check AFR's and check for air-leaks.

AFR is most important or you will have (much) bigger issues than cutting out if motor runs lean.

Pics for examination
 

Here are some pics of the bay and turbo/oil drain from the under side.[
http://forums.pelicanparts.com/uploa...1232818592.jpg
http://forums.pelicanparts.com/uploa...1232818609.jpg
http://forums.pelicanparts.com/uploa...1232818635.jpg

http://forums.pelicanparts.com/uploa...1232818693.jpg
http://forums.pelicanparts.com/uploa...1232818715.jpg

http://forums.pelicanparts.com/uploa...1232818750.jpg
http://forums.pelicanparts.com/uploa...1232818846.jpg
http://forums.pelicanparts.com/uploa...1232818860.jpg


http://forums.pelicanparts.com/uploa...1232819057.jpg

http://forums.pelicanparts.com/uploa...1232819175.jpg
Let me know if I'm not shooting what you need

How and what do I use to check afr's?

Wide-band Oxygen sensor, Google should get many hits. "Normal" range of mixture on a 930 can easily defeat a narrow-band sensor.

Innovate's LM-1 is a basic readout of mixture, but you can add boxes to log additional information like boost, RPM etc.

Zeitronix is another brand.

You can get a check/baseline on a rolling-road dyno, but this isn't the same as "real" driving.

Personally, I can't imagine trying to watch RPM, boost, AFR and traffic. So I think in-car gauges are bling, and think you need to log the results for later analysis. YMMV.

Could you label where the hoses in these pics go? In the last pic, the hoses coming off the air tubes going to and from the turbocharger?

Also, do you have the dual fuel pumps (front under the tank and rear by the driver's side rear wheel well) on your conversion? I wonder if you are running the proper system fuel pressure.

Hoses and pump
 

Dave,
The hose on the bottom pic is the vent side of the wastegate.
The charge side from the wastegate goes to the bottom of the intake.
The hose on the top pic is oil return from the turbo.
There is a fuel pump in the engine comp on the drivers side rear qtr.panel, but couldn't find a fuel pump under the tank, wher should I be looking?

And Spuggy, I'll be looking for a wide band O2 sensor to get some info.

Thanks guys, and keep it coming please.

Insult to injury
 

Her is a pic of where the mechanic dropped a jack on my baby...http://forums.pelicanparts.com/uploa...1232827952.jpg

The vent for the wastegate should be at atmosphere. I'm picking hairs here, but there may be a slight difference because you're sampling between the metering plate and the turbocharger (slight vacuum).

There will be some disagreement here, but I recommend the charge side of the wastegate above the throttle body.

The front fuel pump should be behind the splash pan for the front crossmember.

Ok,
So my 911 should have the 2 fuel pumps if it has one in the engine bay right?
You can see where the charge side goes to in the first pic shown, just infront of the fan shroud and below (I believe) the throttle body.
I'm calling the can below the deck lid hinge in the last pic the rear fuel pump.
Am I right?
Would those problems you spoke of make it run this crappy ?
Once it achieves 10psi boost it stumbles and completely looses power.

And Spuggy,
What readings should I be looking for when I get the sensor to read the AFR's?
Thanks guys

The two cans you see by the left rear engine bonnet hinge, are the fuel accumulator and fuel filter. In the 930's, the rear fuel pump is located inside the driver's side wheelwell. It's in the forward section of the wheelwell behind a plate. I don't know if your turbo update added the second pump.

It seems your car is accelerating fine up to 10psi boost, is that correct?

Second pump
 

Dave,
Looks like I don't have a second fuel pump, but Spuggy says he runs ok on mild turbo upgrade...

Yes, the car runs well up to 10psi where the boost limit is, then it sputters and the boost guage goes up and down rapidly from 5 to 15 as it cuts out, sputters, looses power and basicly worries the heck out of me.
Shouldn't the wastergate limit the boost a 10psi but not dump all the boost?
I don't know never having had a turbo before.

The mechanic who worked on it said I should get 2 or 4 prong plugs and a high enery ignition system... would that really help?
I'm pretty sure the stock 930's didn't have that stuff in the late 70's.
Thanks for the comtinuing help.
Sam

Do you know if your turbo system is setup with an overboost sensor switch? This might explain why the car acts like it just run out of fuel or ignition.

sensor switch
 

How, where do I locate the switch if I have one?
Thanks,
Sam