944 Turbo S Engine Rebuild Thread

[Eldavo]

looking at the pics, I think bolts are for the split rims.......?

Yup, 40 per wheel - installed individually by hand

I got this far before going away to a conference for the week, hopefully get them finished off on Friday and pick my splitter up from the bodyshop then too - fingers crossed I turn a wheel at the weekend.

 

[TTM]

 

[Eldavo]

Got the bolts all in and some new (wider) rear tyres fitted last weekend - had a small window of time I could’ve got the car out but it was running pretty poorly and not idling well - running very very lean on the lambda/AFR screen.

This week I’ve checked the fuel pressure at the rail, switch tested the injector circuits, tested each injector individually and pulled the rail so they fire into cups to check activation, checked the TPS continuity and potentiometer readings too so reasonably satisfied that it isn’t anything mechanical/electrical/physical.

Going to adjust the req_fuel setting in the ECU (that turns up the fuel scaling across the whole table) and see what effect that has from cold start with higher fuel tip in and higher ideal speed through to normal running temps and idle/light load. Annoyingly I have a free day on Sunday but the weather is currently 1ºC here and supposed to be worse at the weekend so will just have to wait and see.

 

[TTM]

Kind of surprised that putting back together the wheels does not need special sealing between the rims and the centre pieces, where the bolts attach. At least I had heard something along those lines years ago.

Advancing the inlet cam timing increases overlap so it's not surprising that you find yourself running lean suddenly. This also means that you are to expect a serious bump in power once you are all back in order.

 

[Eldavo]

Kind of surprised that putting back together the wheels does not need special sealing between the rims and the centre pieces, where the bolts attach. At least I had heard something along those lines years ago.

Advancing the inlet cam timing increases overlap so it's not surprising that you find yourself running lean suddenly. This also means that you are to expect a serious bump in power once you are all back in order.

Proper 2/3 piece split rims do need sealing but these are just look-a-like split rims, they’re actually one piece 18” wheels with fake “bolts”. I really like the look of them but they are reasonably heavy and will obviously have an affect on the handling, I have 17” Fuchs-style wheels from R&R Alloys that I use for trackdays and they are really light and well made. The powder coated black 16” CS wheels I have will get sold at some point as they won‘t fit over the new front brake calipers.

Will try and get the fuelling sorted tomorrow afternoon depending when I finish work (Given how lean it’s running - even with cold start enrichment I should be expecting a fairly decent power bump then), MrsEldavo is away on Sunday and LittleMissEldavo is out that day too, but typically the weather forecast is rain, flood alert and low single-digit figures

 

[TTM]

If the roads are dry you could already redo the low load areas of the fuel and ignition maps by driving around gently, but I am not saying this to tempt the devil if the conditions are too harsh.

 

[blade7]

Yup, 40 per wheel - installed individually by hand

I got this far before going away to a conference for the week, hopefully get them finished off on Friday and pick my splitter up from the bodyshop then too - fingers crossed I turn a wheel at the weekend.

View attachment 489

Nice. I loved the BBS split rim wheels on my old 328 Coupe.

 

[Eldavo]

If the roads are dry you could already redo the low load areas of the fuel and ignition maps by driving around gently, but I am not saying this to tempt the devil if the conditions are too harsh.

Added about 40% more fuel as a req_fuel multiplier and got it up to temperature on the drive, fans coming on, nothing spewing out of the bottom and idling with lambda 0.95-1.00.

Better go out for a spin then . . . .

ABS pump still not sorted so will need to put the 996 one in this year after all, panicked at the end of the drive when the brakes did nothing but the pedal firmed up straight away - phew. And the wrong circuit that I fitted on the back of the PS pump shaft has come off again allowing the shaft to prop out an inch so no PS - I have the correct clip in the garage so that’s no drama to sort (just a bit messy) - best flex those guns and hit the very damp and greasy roads.

First reactions were startling, I tried to blame the brand new tyres, but the reality was torque where it wasn’t ever before and pulling like a train from 2k rpm (I’ll need to check the logs to see what boost and when spool-up was) - the result was a small rolling burnout up the street while my passenger creased himself laughing.

Didn‘t really get to put the hammer down more than 30-40% throttle and stayed in double digit speeds but so so (so so so) happy - I’d been terminally frustrated with the performance before as it was monumental, but in a narrow and almost unusable place - but I had to put a brave face on though given how much work had gone into it.

Can’t wait to get this mapped properly and on some dry roads. Thanks again Thom for the push in the right direction

 

[TTM]

To be honest, when I got my 16V engine running I found it a little dull down low to the point I wondered if I had not made a huge mistake spending that much on an engine that was already far better than the 8V up top but a bit dull and unresponsive below 4000 rpm, above which we hardly ever have to run these to get going at legal pace. Having the horribly heavy ttv flywheel lightened, cam timing adjusted and inlet restrictions removed fixed all of it and transformed radically the driving experience. Because the 16v head flows such an insane amount (330 cfm on a 968 head) that engine will be very sensitive to changes that would make a minor difference on an 8v engine which is so badly flow-restricted.

I am so happy for you, as you have been through a lot of tedious issues and it seems the tip of the iceberg has now surfaced. Take it easy as the beast now awakens, you will be surprised how much special and humbling your good old 944 turbo will feel when it's all tuned up... I reckon there is no "upgrading" from a sorted 16v 944 turbo.

 

[Eldavo]

My mate came out with me for laptop holding duties and potential pushing just in case. He couldn't believe how different the car felt just from the passenger seat. He picked up a Ferrari F430 last week to replace his modified 996 Turbo he sold last year, he thinks the 996 was faster as the F430 needs more time to rev out but when it does it sounds incredible and feels very special. He said that on a dry day punching out of a corner he reckons I’d gap him in the Ferrari - whether I do or not, we’ll have fun finding out that’s for sure

 

[TTM]

On a straight you should get him considering that a friend was quicker than a F430 Scuderia on the Autobahn with his 3L 8V.
Out of corners with much more torque and less traction I'm not so sure but your car will feel none the less very special in its own way and that's the whole point in the end.
May I just suggest sourcing another set of 17" wheels as it doesn't sound like your heavy 18" alloys will allow the chassis to be as playful as it can - one thing I love with mine is to steer it back and forth with small inputs under half throttle at medium speeds as the rear end lightens up, a situation where one can enjoy the virtues of a transaxle layout and its perfect weight distribution in just enough instability to have some great fun though that requires full concentration. Heavy wheels which add inertia at every corner don't help there, as I recall from driving a friend's C6 Z06. Obviously this is made possible with the small-ish turbo which hits really hard at 4k rpm. Your larger one might be different but it just might and you will soon meet the limitations of the std intercooler anyway... Sorry, talking like a senile old man repeating myself.

 

[Eldavo]

I do have a set of lightweight ‘Foosh” 17”. Wheels from R&R Alloys that my track/summer tyres are on.

I’d rebuilt the power steering pump but the original circlip that held the shaft in place had gone missing and the generic thin replacement failed so the shaft popped out a couple of inches (oo-er missus) and the power steering pump stopped pumping.

Decided to rebuild a spare pump I had (that was absolutely caked with grime) as that was all original and had the correct clip in it - if anyone can get a source on the clips used for the PS pump shafts I’d be very grateful.

Ignored my own advance of always go to Porsche first and ordered a seal kit from eBay for the scandalous price of £32 as when it appeared in the Porsche packaging the part number comes up as £11.50. So a word of warning to others as I repeat the mantra of always go OPC first - otherwise your “9” that is “Apart” will leaf to your wallet being more apart than planned

Swapped the pump over last night and despite best efforts it turned into a messy job as ever. I’ve also sorted the fuelling maps out a bit and will be getting out in the car this weekend hopefully for a bit more of a shakedown and to do the fuelling maps.

Here’s a before and after with that all important kit part number should others need it in the future:

 

[TTM]

Grime makes a great protection against corrosion.
Many bolts and nuts on my last engine which were all shiny are slowly fading away as the engine bay has been the driest in ages... you can't have your cake and eat it I suppose.

 

[Eldavo]

Grime makes a great protection against corrosion.
Many bolts and nuts on my last engine which were all shiny are slowly fading away as the engine bay has been the driest in ages... you can't have your cake and eat it I suppose.

Previous oil leaks have kept the underside of my car well lubricated and protected!

I’ve also ripped out the terrible Chinesium LED Headlights with no beam pattern or cutoff with some Philips ones - still and MOT fail (obvs). I replaced the headlights themselves with one of my spare pairs, also replaced a self-levelling motor that had stripped the screw thread and fitted a new set of adjustment screws and clips too.

Final task was to roughly align them so they weren‘t blinding passing aircraft - I parked my other car up on ie and marked the hotspots and beam cutoffs on the garage doors with tape and then parked the Twbo in the same spot and got it near enough.

Old bulb on the left and new on the right:



New bulbs in progress:



Some Victorian London fog the other night was a good excuse to check the beam pattern on low beam (pre-alignment):


And the same for high beam:



Highly technical alignment rig but it’ll do:

 

[marty]

Which Philips LEDs did you use?

 

[Eldavo]

Which Philips LEDs did you use?

Philips Ultinon Access bulbs - £40 from Amazon. They are an MOT fail though!

I changed the fog light and main beam lights for H3 LEDs too: Link

Here’s a pic of the headlights done and one side fog and main done vs halogens:

 

[Eldavo]

Dealt with a slight issue too - when I changed the camshaft orientation I had to remove the front bearing bridge that holds the camshafts down. When I refitted it I didn’t realise you’re supposed to use Loctite 574 anaerobic sealant and fitted it dry - ended up with an oil weep from the join.

Thought it would be quite easy to sort so whizzed off the cam cover and the 4 bearing bridge bolts but forgot about this one bolt that’s hidden behind the cam gear - doh!

 

[Eldavo]

So I took the dog for a walk to the corner shop - picked up a couple of 660ml bottles of Moretti and fueled by beer I removed the belt cover, released the belt tension, removed the front cam cover, cam gear and rear cam cover and then finally the bearing bridge.

Reinstalled with a 574 replacement I borrowed from my Indy’s - wazzed it all back together and then added a new Bosch cam sync hall sensor while I was in there for something I have planned.

 

[marty]

Thanks.
You didn't go for the Philips bulbs for the H3's then.

 

[Eldavo]

Thanks.
You didn't go for the Philips bulbs for the H3's then.

I was less bothered about the beam cutoff for the fogs and main beam but actually it seems ok.