WRX/Porsche Karmann cabrio 1303

[karmann79]

respect

[dub_crazee]

looks stunning rich! officially done and dusted then?

[ricola]

I don't think these are ever really done! Last thing, before at least stage 1 is done, is to make up some new sunvisors. I'm going to make up some early style smoked black perspex ones..

[ricola]

The pictures above drove me into coming up wiht a replacement set of sunvisors quickly! Although they matched the headlining I think they clashed badly with the roof down. I'd have the idea of making up some smoked plastic ones, in the style of early VWs, for a while so decided now was the time! Above is what a stripped sunvisor looks like, all this just to get the pivot.


I then made up a hinge assembly and cut some 5mm tinted perspex to shape and this is how they ended up, I'm very happy with this look.. At the same time I also painted the rear-view mirror base black to match.

[ricola]

I got fed up with messing around trying to trick the stock ECU to make the correct boost with my much modified from stock (subaru) intake and exhaust so I have now fitted a Gizzmo MS-2 electronic boost controller. This has closed loop boost control as well as turbo timer and FCD (which I won't be using). It now finally makes 1.1 bar without overshooting and hitting the fuel cut but I will still be playing with the rate at which boost comes in. I had a second ashtray surround which I welded up and modified to fit the Gizzmo controller. It certainly feels a lot quicker now so my times will undoubtedly be better!

Cheers for the Gizzmo recommendation Wally

[Wally]

Good to hear it works as well for you as it did for me
You have it way neater installed too btw

[ricola]

There's still some fine tuning to be done, I was put off course by a leaking pipe so gains were way off to the point that I thought there was a problem with the solenoid! Proper clips on the solenoid pipes sorted that and I'm currenty using a duty of 66% and 5% gain. I did think about putting it under the dash with tie wraps but thought I may as well make it semi-permanent, lol. I may end up putting it in the glovebox to look a bit more subtle but for the moment it's good to have it monitoring things with it in view..

[Wally]

Yeah, its nice that it operates as a boost gauge as well.
I now use 25% gain, which works well. At 30% it can overshoot the target boost a little I think, but I haven't played much with gain.
60% duty is a about 60% over wastegate boost with my set-up (Tial external 44mm gate). Just for your reference ;-)

[ricola]

While playing earlier I got it to 1.09 bar during duty set-up in open loop mode and I've switched it to closed loop now, not driven it since but hopefully that should keep me safe. It's amazing how variable the duty levels are across different cars, I was initially working around 20% and thought it was changing but the leak and variability run to run fooled me. My VOS map is good for 18psi I believe so that's a fairly safe level, still managed to surprise an Aston Martin earlier near Gaydon

[ricola]

Time for an update...



I took the car on track and although it was struggling with the ignition side of things, at 1.2Bar boost, it was going OK. GPS'd it at 130mph with loads more to go but then I blew the intercooler pipe and sudden loss of power along with clouds of smoke out of the back end! You should be able to spot the hole in the turbo to chargecooler pipe in the pic above..

I was hoping for an easy fix (and excuse to upgrade to silicone pipe), worst case it may have been the turbo but I have a spare one of those. I've also got some newage coilpacks on the way to upgrade from the old ones which degrade quite badly with age.

The parts arrived so I got cracking...

New silicone pipe bought to replace the holed one, this should be good for much higher boost too.


Unfortunately after swapping the pipe and the turbo the oil filter seal blew dumping oil all over the garage floor. I tried another filter and the same thing happened. Googling pointed towards the relief valve on the oil pump being jammed shut.



After fitting another oil pump the engine seems to run ok with normal oil pressure, albeit chucking out a lot of smoke from the oil it has in the intake! The old oil pump relief valve was jammed solid almost closed, even with the pump off the car I can't move it!

Changing the pump meant stripping the rear panels off the car as well as cambelt etc etc so now I had to refit and seal things back up. I'm also using the opportunity of it being up in the air to convert to newage coilpacks which will also help it run better on boost. I made new looms for them tonight as a change and will bypass the old ignitor as the new coilpacks have built in igniters..

The early optimism ended in disappointment, I went for a drive and it was gutless and the oil screen didn't improve. I got a compression tester and one of the cylinders showed no compression at all. There was nothing to do but pull the engine and get the head off to assess...



You can just about make out some damage to the top of the cylinder wall



and if you look carefully you can see that the ring is distorted, I'm assuming that the piston ring land has failed underneath...



So, after contemplating my options and considering where I want to be realistically with this car I've decided to rebuild it with a 2.5 sti bottom end. It's a semi-closed deck block but they are good for about 450bhp, I think that should be enough in a bug!! I was also considering a forged 2 or 2.1 stroker but for drivability the torque of a 2.5 wins for me. I'll upgrade the externals to allow greater power at a later date.

[Wally]

Man, thats some tough luck all together..

You have great perseverance though!

If at all possible, maybe upgrading rods and pistons on the 2.5 would be a good idea to prevent any ring or ring land problems in the future?

[ricola]

I'm considering my options for pistons, if I stay at a relatively safe tune to 400bhp, stock should be fine. The drop in forged tend to have poor clearances. Hone to fit seem to be the best but that means splitting the block again, not necessarily a bad thing to do I suppose!

[Wally]

Originally Posted by ricola

I'm considering my options for pistons, if I stay at a relatively safe tune to 400bhp, stock should be fine.

'relatively safe tune' with stock parts is the key word here.
There are only a few that can give you that power under those bounderies...you know what I'am saying here I'am sure

The drop in forged tend to have poor clearances.

Although very true (I would say drop-in & forged does not go in one and the same sentence) I was actually gonna say that for the stock block too: at double the power the stock rings may not have the correct clearence either for this.. maybe that is also the problem at hand with what your seeing now?

[dub_crazee]

Bad luck

These things are sent to test us - i found myself in a similar positon after a week of driving (but with my gearbox)

Atleast it gives you something to do over the winter months cant wait to see the car on the show scene next year!!

deano

[graham]

Argh how feckin annoying Rich , cars have a habit of driving ya crazy at times I am sure you'll get it sorted in no time though.

All the best Graham