I have just got my car back after 5 months. It's a -78 3.3 Turbo.

The engine has been totally rebuilt, new bearings and blueprinted and balanced.

Crankcase is gasflowed, cylinderfoot preparation, Pauter rods with ARP bolts. The heads are ported to 40mm inflow and 38.5 mm exhaust and 935 rings to seal the heads and GT2 head bolts.

3.2 Carrera headers, free flow exhaust. Intake manifold ported to 40mm and intake tubes are 40mm. Titanium retainers, race valve springs, new guides and rockers. GT2 cam. 935 clutch, new flywheel.

A K27 high flow turbo and a big IC made of Setrab elements. A **** to manually adjust the turbo pressure. A free flow air box made of carbonfibre.

A big front oil cooler is there to give better cooling, also modification of the fan.

The CIS system is prepared only in the WUR and there is an extra fuel enrichment system with an injector that will give 1400 cc/min at 6 bar pressure. And in the front there is an GT2 fuel pump.

The chassie is totally new with polygrafit bushings, rear uniballs, bigger torsion bar in the rear, also RSR Bilstein rear and Rennen 2 front shocks, 22 mm front and rear adjustable sway bars.

Rebuilt rear original rear breaks and new Big Red in front.

Inside roller cage, striped of the interior, 4 point harness, Momo race seats.

Exterior modifications consists of a 965 glassfibre kit.

And the car just runned marvelous for 800 km, then the problems started. The company that made new fuel hoses had used hoses for air, so suddenly the "fuel" hose ruptured.

I went to the company that deals with this in my home town and they was really confused why the other company had used air hoses. They made new ones for me. And I replaced the hoses. And I went for test drive without using the extra fuel enrichment.
The first time the car was just marvelous again. With a good air/fuel ratio according to the lambda prob and the temperature of the exhaust.

But next time it was very lean and no power at all.
It can good very good one time but next time very bad.So it is intermittent this problem.

I have checked the WUR and it looks ok inside and when I push some air in it when the engine is idling it almost choke, so it's working. The fuel pump works at it should. I have removed the air intake and had a look at the air plate and it worked very good no sign of jamming.

No body in my home town knows anything about old Porsches. And the company that did all this work is lokated 670 km from my home. So it takes a wile to drive back.

So any advise that you guys can give me is much appreciated. Why does the car run perfect one time and next time very lean? I should add that I havn’t used more than factory turbo pressure of 0.8 Bar.

Peter
Sweden

 

Hello there Aspemo, your car looks great! I know this doesn't answer your question but why are you not using your fuel enrichment? Did you modify your WUR and add a seventh injector? Where did you position your seventh injector and what system did you use?
I had all sorts of problems with my car running intermittent, one minute it was like a rocket and the next it was not. If you have had your WUR modified the chances are that this is your problem, my shop ended up putting a 965 WUR on my car which works great when the engine is up to temp but runs lean for the first couple of minutes on cold start. There are guys that make the WUR adjustable so that you can dial all these problems out, I’m sure someone with more knowledge that me will give you a link or contact number, Good luck!

 

Hi there

Thank you for your answer. The reason why I havn't used my enrichement is that I would like to see that the car goes smooth first and then add more turbo pressure and more fuel.

The 7th injector is located in the IC where it attaches to the throttle "intake". It is called MF2 Mapfueler 2.

I will make a call to the man who did this modification and ask him about the WUR.

 

If you take your car to the track or ahve sustained high speeds, toss the 7th injector and get the Imagine Auto fuel head. A MUCH better idea.

 

Thank you RSRS but my CIS system will only live for a couple of months. I will remove it as soon as the seson is over. I can drive to september.

I will then go EFI and also rebuild my gearbox and add a quaife diff.

The car goes pretty good now but I cant load more than 1.0 bar before the fuel supply is to low. And the car goes to lean and the exhaust temp goes up.

Obviusly this extra fuel supply with a 7th injector is not a good ide. But now I have tryed that.

 

Good - stay at .8 bar, keep the engine alive until you have EFI!

 

Your car looks stunning.

That 7th injector will make uneven fuel enrichment. Maybe you should consider lowering you boost pressure to 0.6bar for now until you go EFI.

Here is a cut of a Rennlisters reply to someone about the WUR

You can get yours rebuilt and modified to be Fully adjustable from Leask Engineering for about $300. Considering a standard rebuild already costs $250, another $50 to make it fully adjustable makes sense.

He did mine and was able to tune cold/hot and boost pressure exact to spec. If he knows what mods you have, he can pre-tune if for you using gauges and such.

You can contact Brian at bleask@***.net and he'll send you some nice photos of the mods and full manual.

 

You have the same 7th injector as me, mine is positioned where the intercooler connects to the throttle body, I am told by my shop that this set up with the ported intake manifold and heads is quite safe, although holding the car flat out is a bad idea, to be honest I think unless you are running low boost with a high end intercooler and top notch fuel you are asking for trouble if you hold your car flat out for long periods. I might get slated for admitting this but on the way to Le Mans this year I hit 180mph, I didn't hold it there but the car felt good, in fact it felt like it had more in it, mine is running around 0.9 bar and just shy of 500bhp with similar mods to yours, although mine has a version of the GT35R BB turbo and 964 cams. Have you had the car on a dyno? I would be interested to know what your engine is putting out.

 

Did you confirm the speed on a GPS device ?

 

Wow beautiful car...what wheels are you running?

 

Hi

No unfortunately my mech didn't have time to do this. I was knocking on his door and I was very eager to get my car back.

A question for you JBL930 how do you control the 7th injector? By a mapregulator or by a microswitch that reacts on the turbo pressure if so what pressure do you have as a trigger?

The wheels are OZ splitt ´8,5 x 17 and 10 x 17 and I had them powdercoated. But I'm not satisfyed with the result. They have the ET for a 928, so I have to use rather big spacers both fron and rear.

I noticed to day that I need R tyres and I would like to use 9,5 x 18 and 11,5 x 18 ,something similar to the RSR 3,8 Speedlines. I think that Tramont a french company has 3 splitt wheels that you can order with size and ET as your preferenses are.
I have already bought an manifold and lines, throttlebody etc from an 3,6 Carrera. So now I need the rest.
I think it would have been cheper to buy a 993 Turbo instead of this insanity. But it's really fun to create something that is not a stremline product.

 

Two GPS devices, my Snooper and Tom Tom, the Tom Tom is a little quicker at picking up the change in speed, my speedo goes off the clock at 170mph and to be honest is really inaccurate anyway so I never rely on what it says, I think the car has more in it but I’m afraid of pushing any further as I don't have anything to tell me if in danger, I will be going Motec next year, pretty much following in JamesE's footsteps, I want a 200mph retro rocket and that's the way forward!


"A question for you JBL930 how do you control the 7th injector? By a mapregulator or by a microswitch that reacts on the turbo pressure if so what pressure do you have as a trigger?"

I don't have any control over the 7th injector, I’m not running a EBC so 9m have set it up to add fuel when needed, it's a bit of a mystery to me, all I know is it seams to work just fine, the car wasn't running very lean anyway so the 7th injector is just a bit of a safety net, in an ideal world I would have gone Motec from day one but with all the other purchases you have to make I settled for this (temporarily )

 

Cool, I have 3 GPS devices