Carpokes Porsche Forum

This thread will be a poor attempt to begin chronicling the future iterations of my Guard's Red 944 and hopefully pick the hive mind's brain about a few issues I'm dealing with right now.

I bought this car in the winter of 2019 for a fairly good deal as the market on 944s only really began to rocket to where it is now shortly after. It wasn't a basketcase necessarily but it needed some love as the previous owner cared for it ok, but wasn't really a car guy. Mediocre respray, timing and balance belts needed to be done and it was immediately obvious the balance belts were timed improperly, the shocks were beyond blown, etc.... It had a decent set of 17" turbo twists and fully converted turbo front end and the interior was pretty good so I felt pretty good about it.
I did a bunch of maintenance, drove it around, did a few track days. The stock 8v motor was well used and felt pretty bad, I messed around with offset cam keys, gave it a good tune up, it still was mediocre and started smoking slightly on cold starts. Very likely needed a head refresh that I didn't really feel like doing. At that time I had a turbo e30 that was slowly turning into a stage rally car and one humongous project/money pit at a time seemed like enough....

You'll find good company here with whom to share experiences and ideas. I know you've been part of the group for a long time but here's a formal welcome to Carpokes following your first post! Thanks!

So somewhere I believe in the spring of 2020 I bought a complete 2.5 16v "S" motor, it was in pretty good shape and I very well could have did some basic maintenance/seals/belts and stuck 'er on in- but it happened to be the beginning of covid so I was in the unusual position of having both money and time at my disposal so I completely rebuilt the thing. Somehow it seemed logical that while the motor was out I should replace the trans with one with an LSD, rebuild the entire suspension with new bushings, coilovers, etc.... I have a tendency to go way down the rabbit hole, this was a perfect example.

So much later (summer of 2020?) I have a good running 16v, running on megasquirt, S2 intake manifold, wasted spark ignition, great suspension, the car is pretty sweet and a great weekend car and track toy....
The 2.5 16v was still sort of disappointing, at least the top end was much more engaging than the stock 8v motor but it's ~190hp spec was sort of hard to believe. At some point I put together a Rotrex centrifugal supercharger setup for it from some Czech outfit if I remember correctly.

Luckily for me, I didn't have to think too hard about getting the SC setup dialed in or even installed, as I spun the #2 rod bearing (as one does) on my still fairly new motor at the track in October of 2021...

So that was Fall of 2021. I pulled the pan, with hope that I might be able to just stick a fresh set of bearings in it and carry on...but of course the crank was trashed and I would find out later that the cylinder bores had been scraped up by random bits of bearing material.

So out the 16v came, I got a good used crank and spent some time looking for a block to use to put it back together, or an complete 3.0 engine, or...whatever else would come up and sound fun. I considered 07k stuff for a while, LS stuff for a while, neither of which seemed like something that would fit my style or budget.

I contacted a well known parts dismantler about an S2 engine which unfortunately had recently sold, but he had a running 951 he was getting ready to part out so we struck a deal + trade for the Rotrex SC setup I had. I also worked into the deal the suspension and brakes off of his donor 951 that will eventually go into my car for a more complete 951 conversion....
I pulled that motor apart for a quick refresh and immediately realized it too had one trashed cylinder...the seller was unbelievably accommodating and sent me yet another (good) block and matching piston for FREE and over the next few months I built a complete motor out of this giant pile of parts I now had. What started as a "throw a timing belt, HG, and seals at it, and throw it in the car" turned into yet again a complete rebuild. I had the head gone through by my great local cylinder head guy- new guides, valve job, etc...and stuck it all back together. New rings, bearings, seals, cutring headgasket, ARP headstuds, sent the crusty turbo to Evergreen for their "raptor" rebuild, talk about scope creep...
This is kind of an enlightening comparison of a stock k26/6 vs Holset HX35 that I use on my e30 rally car...also on a 2.5 liter engine...

So that basically brings us to right now (mid winter 2024) Got the motor in and buttoned up over the last couple weeks, went pretty smoothly other than a couple bonehead moments like installing the motor and intake manifold and then realizing the brake booster heat shield was sitting on my workbench still...
And...it's in and ready to rock! Almost....
So the motor is in and ready for first start and break-in but I'm battling a textbook no start "no tach bounce" scenario. I've outlined where I'm at diagnosing it in this other thread: https://carpokes.com/viewtopic.php?t=2704 .

If anyone in here has any input as far as some glaring NA-to-Turbo swap wiring detail I've missed, by all means let me know! It's looking like the ECU is probably bad but that's always my very last assumption and I'm never hot on the "throw parts at it" method of troubleshooting...

Awesome right up. I'll take a look at the no-tach-bounce thread you started and see if I can help. In the meantime, are you sure the tach is powered and hooked up? Which harness are you using for the motor, and are you using both the turbo DME and KLR? With all 944 turbo parts, the tach signal starts on pin 21 of the DME and goes through a red, square 4-pin connector in the passenger footwell. The tach signal on pin 21 is a green wire with black stripe. That wire needs to be fed to the tachometer, and the wiring doesn't usually match up on its own when putting a 951 in a n/a car... If you didn't go through all that, I can help with the wiring if needed.

You rock Tom, thanks for the insight. I'll answer the no-start specific questions in that other thread for the sake of keeping things organized. You've already given me a couple little things to double check that I haven't really looked hard into yet.

Cheers!