It has been suggested that the Turn 1 pump, being the same external dimensions and appearance as the factory GM pump, is simply a factory pump with the pressure relief spring/valve modified or removed

I ordered one yesterday afternoon, they have one specifically for the LS motor and 944 steering rack...

Well DUH.

Hmmm, well if it works and I don't boil fluid on track like Tony did with the stock pump it's worth it.

The Turn1 pump is an off-the-shelf brand new GM f-body pump that is modified for the pressure and volume requirements of the Porsche R&P. It works exactly like the stock Porsche pump (because it's providing the exact same pressure and volume), except it doesn't leak or make funny noises like the Porsche pump.

I actually messed around with the stock pump i had trying to get the pressure and volume right (and there is more to it than just the spring), but in the end it's pretty difficult to ballpark it with no tools to measure the results! If you ask me the Turn1 pump is a necessity for these swaps.

Hey...

Do yourself a favor and have V bands installed on the headers.

That was a mistake I made before I remembered what a pain in the ass 3 bolt header flanges are.


TonyG

Yeah. Seems just like stock in its operation to me.


TonyG

From my understanding... which makes sense, is that it's not so much a pressure thing. It's a volume thing.

The pump generates too much volume at higher rpms...which is where you spend your time rpm wise on the track (which explains why it only affects cars... both F body and 944's that are used on the track BTW).

When this happens (more volume that what is needed due to sustained high rpms) the fluid is internally bypassed and recirculated. It this action that overheats the fluid. And no oil cooler will help because it's occurring internally in the pump itself.

TonyG


PS> I could be wrong... but that's what I was told and it would seem to make sense. All I know is that it fixed my problem plus I have a brand new pump which is one less thing to leak/fail.

I honestly don't know what volume the stock GM pump puts out in comparison to what the Porsche rack expects. I asked in numerous places and nobody could tell me! Of course, i'm sure TurnOne has the answer to that, but i wouldn't expect them to share....

However, from what i've read the stock GM pump puts out about 900-1000psi and the Porsche system puts out around 1200-1300. The Corvette system (same pump, different pressure spring) puts out approximately 1200psi as well. You can go to GM and buy the Corvette pressure spring and "body" (not sure what it's called). When i was messing with it all i was shimming the f-body spring to achieve a higher pressure and it felt great, but the fluid would eventually boil. I believe this is because it had too great of a volume for the Porsche system and the fluid would just recycle itself into oblivion. But, eventually my pump started making noise (crappy reman, plus i had been messing with it, so who knows!), and i just decided it was time to call TurnOne. Fun times though! :)

Very true!
However, i did the next best thing and welded some large washers with one side cut off to the bolt heads. That way the bolt stays put while i'm tightening the nut. Still wish i had v-banded the headers when they were off the car, though...

Well, the shop was sort of in a holding pattern waiting for parts to arrive. They pretty much finished up the wiring harness. Yesterday almost all the parts arrived: bellhousing, headers, oil cooler core, water temp gauge, muffler. We're still waiting for the Turn 1 PS pump, the clutch and flywheel and I need to order a cam.

I'm debating between the Texas Speed 228R cam and their 233/239 cam. Any thoughts?

Things are going well with parting out the turbo stuff I don't need. I'm down to the head, motor mounts and my 2 sets of DME/KLR. I still have a few other things like an alternator, etc, but I've sold most things of value.

OK, I believe this is a new land speed record for LS swap... Holy crap Doc, Nice work!

Now to get it wrapped up, and some driving feedback!

the 233/239 cam is going to be too big. That one is going to be over .600 lift and then you will need more than beehive springs and your stock rockers and pushrods will be stressed. That's also a cam for over 400 whp and will likely have more issues with vacuum at idle. I thought your car was going to be full-emissions compliant too?

Yep, I need it to be emissions compliant, so if the larger cam isn't going to let me go through smog, it's out.

Texas Performance recomended beehive springs and different pushrods for the 228R cam, I was debating going to roller rockers as well.

The ‘while you’re in there’ effect can strike the V8 guys too! ;)