Rennlist - Porsche Discussion Forums - Official Turbocharged or Turbo swapped N/A Registry

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Official Turbocharged or Turbo swapped N/A Registry

Guys, I had this idea last night when I started to realize just how many guys here were running successful turbo swaps in N/A cars, despite the conventional wisdom of "sell the N/A and buy a 951." I wanted a place to collect information on these unique projects that we all put lots of time and energy into, and give a place for guys who want to attempt the project to look through and gather ideas. I'll go ahead and start.

My car is a Nautic Blue Metallic 87S with an 8 valve turbo engine swapped from a wrecked 86 951. I am using the 86 bell housing with a 6 puck spec clutch, aluminum flywheel and pressure plate, and stock S torque tube. The head is a stock 8 valve turbo head with a late header and 2 piece crossover. Basically stock exhaust for now. LSD tranny, tranny mount, axles and M030 sway bars came from an 89 TS, suspension was very recently gone through and replaced with mostly early N/A stuff. I'm running early control arms and modified early rebuildable struts and VW fox mounts with coilovers in the front and 28mm T bars in the rear and new shocks all around. The rear trailing arms are stock 86 951 units. The ride is stiff and sporty, though its going to be getting a good bit stiffer here pretty soon. The spindles I'm using are unmodified 86 turbo units with stock 86 951 brakes. The front is stabilized by a very large strut brace which had to be ground down and custom fit to my car so that it would clear the fuel rail, the intake, and the brake booster heat shield. The car is early 23.3mm offset front and rear.

I'm just now finishing up a rather drawn out megasquirt install, using a ford 36-1 wheel welded to the front of the crank pulley and the matching ford VR sensor spliced into the factory speed sensor harness. I have no A/C and no power steering, both my alternator pulley and crank pulley are early 5 rib units and I am not running an "A/C delete bracket" but rather just a short belt forced over the two pulleys. My car runs no Idle valve, on a cold start it fires up and idles ~600-700 rpm, rising up to 1k when warmed up. It pulls 19" HG at idle, so it seems pretty healthy. The turbo is a slightly breathed on k27/8 pushing air through a very large FMIC and 2.5" hard pipes. Its a nice unit, but I dont recommend it for most applications since it was definitely a "custom fit" type deal. I had to delete the headlight motor to make room for my intercooler piping, so for now the buckets are shimmed up with brackets, but I hope to be doing some DIY GTS style lights in the not too distant future because I don't really like the look of the car with the stock lights pinned up.

The car is setup to vent to atmosphere through an HKS SSQ BOV. The wastegate is a modified stock unit, though I really need to upgrade this bit. Still, it does its job and holds boost flat to redline. My shift linkages are mostly stock, except that the lever inside the cabin has been shortened by ~1.25". I'm running a 951 front clip along with the light covers and badge panel, but I'm using the stock S fenders so they had to be cut slightly to fit cleanly and up close you can definitely tell it isnt factory. The wheels are 996 Narrow body twists, 18x7.5 ET 52 and 18x10 ET 65. The rears needed 32mm spacers and they look peeeerfect, the fronts fit without spacers but would look better with a 1" spacer. Fenders are not rolled at all. I had to take the wiring harness and gauge cluster from the 86 951 as well, that was one of the more unpleasant parts of the swap for me because I detest interior work. I am still running the KLR to control knock and run the factory boost gauge. TDC reference is provided via the stock reference sensor in the bell housing.

My WB and boost/vac gauges are mounted in a fiberglass A pillar mount, its not the best looking but its alright. The seats are stock S pieces and mine happen to be powered, which is kind of cool because this is pretty uncommon as I understand. Time hasn't been that great to them, I'll be replacing them with racing seats as soon as I can. It is pretty sparse of creature conforms but the ones I do have all work. That's power sunroof, radio, heat, and power windows basically. Everything else electronic or otherwise unneeded has been stripped from the car. I will be putting a mazda FD oil cooler under the badge panel in line with the stock oil cooler to keep temps under control on the track. The fuel lines have all been replaced with E85 compatible pieces, along with 80# high Z injectors and a Bosch HV fuel pump.

Not sure what else to add here, anyone contemplating turbocharging their N/A cars, it is very doable if you are smart about getting your hands on parts cheaply and you do the work correctly. It was an incredible learning experience, I highly doubt that any project I've worked on before or since taught me as much about the 944 or automotive in general. I am making more power than many 951s here on this board, and on a budget that would not have allowed me to buy most of the 951s here. For somebody still in school, this would absolutely not have been possible had I started with a real 951. For the amount of money I have in my project, I'd most likely still be driving around a stock car if I had really cared about the car being a "real" one. I hope other guys who have gone a similar route post details of their builds and the experience, lets show these guys that if you have the gumption, time, and knowledge that in many cases, the old "sell your N/A and buy a 951, it'll be cheaper" simply isnt true.

Mine is nearly identical to yours. 87S with an 87 turbo engine.
There needs to be a sticky up here about "how to convert the wiring harness to match up".

My whole thought was that I wanted to rebuild an engine from the ground up anyway, so, I figured let's go big. Here's the results:

Dry sleeved 2.5L block (I used the block for the S engine)
Rebuilt 8v head
Lightened stock 951 Flywheel
930 Disc
K26/8 with k27 impellar (cheater turbo)
Forge Diverter Valve
Silicone hoses errywhere
A-Tune
Apexi AVC-R EBC
Tial 38mm dual-port wastegate
Full 3" turbo back fabspeed exhaust /w wastegate tie-in and swappable test pipe or cat
Rebuilt stock injectors
3 piece cross-over pipe, 3 piece crossmember
Lindsey oil pan baffle
87+ oil pan
Custom made RX7 (FD) oil cooler with AN lines and adapters
Lindsey fuel lines
A/C delete
Headlamp motor delete brackets
Rear seat delete
951 trans with cooler (open diff)
87+ offset front and rear
993TT calipers, 965 2 piece rotors front
968 calipers, 968 rotors rear
Rebuilt 87+ control arms (Rennbay balljoint, rubber bushing with 968 castor blocks)
Trailing arm, torsion carrier, rear suspension bushing rubber replacements (elephant racing)
KW V3 coilovers front and back (340 lbs front, 630 lbs. rear)
Torsion bar delete
Racer's Edge lower shock mounts
968 M030 sway bars (30mm front, 19mm rear)
996 twist wheels 18x7.5,10
Full turbo body conversion
Custom vent mounted dash panel with oil temp, boost, and AFR gauges.
Momo competition 330mm steering wheel
968 CS armrest delete

I'm ashamed to post pictures, my car isnt 1/4th that clean. Yours looks great! Unfortunately I didn't really document the swap procedure very well as far as pictures go. I have lots of notes, but I was interested in getting the car running quickly, not having records of the process;.

I think understanding the differences between the turbo and NA is a good start. Then, knowing how to integrate the engine into the body harness in the next challenge. In addition, it's fun experience in reverse engineering; understanding why Porsche put every part in the way they did.

It's kind of funny in hindsight, because looking back I did so much work that I later had to go back and redo not because it wasnt done right the first time, but because I started to mod the car heavily. When I first built it, it was basically just a copy of a stock 951 and when it was "new" you would have been hard pressed to find any signs that it was NOT a factory 951. Truthfully...the car stayed stock for ~2 weeks after I got it running..after that, a k27/8 with matching chip went in. After that, the stock 951 clutch with unknown mileage was slipping under boost, so the spec clutch and flywheel went in, which being a 6 puck clutch and the whole thing 1/4 the weight of the stock assembly, was a pretty significant change in driveability. Now I'm using very little of the harness I went through so much trouble to put in, and literally none of the stock parts except for the motor and radiator/fans basically. The next thing I'll be ripping out is the water cooling since my new turbo is oil only.

What did yall do with S engines?

Kris, where did you get your block sleeved?

My S engine spun the #4 rod bearing, so, it was toast.

Spencer, I got the block sleeved at this place in Pasadena called Foreign Machine Service. Jim, the owner, is an old timer with about 40 years of experience. He mostly does work for all the Jag, BMW, Merc, and other European dealers in the area. He did a hell of a job honestly, but, it wasn't cheap. He recommended the sleeves over re-coating the cylinders. Supposedly, the dry sleeves in this orientation are a good choice for turbo engines in particularly because they cool the cylinders slightly better.

He also did the headwork for me, but, that was mostly basic; valve guides, new studs, cleaned, etc. Come to think of it, he also welded the bungs on my oil cooler too.