Tom. M

LOL..nope that is handled by the rennlist...

Tom. M

OK..lets try pasting those Hackmeister links again..

https://rennlist.com/forums/928-forum/364777-remote-mount-turbo-dynograph-399hp-438-ft-lbs-10-63-psi.html

https://rennlist.com/forums/928-forum/363676-rear-mount-turbo-9-5lbs-12-434-117-03-e-t.html

https://rennlist.com/forums/928-forum/400838-rmt-dynograph-now-with-methanol-injection-475-6hp-526-ft-lbs.html

https://rennlist.com/forums/928-forum/312170-rmt-v-2-rear-mount-turbo-spy-pics.html

and finally the island of lost toys:

http://forums.pelicanparts.com/showthread.php?t=390501

89 928 turbo

You can see my latest dyno on Tom's links....A number of things started happening at 4600rpms or so. Turns out "Size does matter"and we found a reasonable threshold.....we have swapped out for 42# injectors from the 30#'s and are in the 50 to 65% duty cycle with the Shark Tuner at 12.5+/-AFR and going to 12#boost will need a larger Turbo to increase the upper HP range....the unit currently on works reliably up to 8 lbs...maybe 9 boost but then it starts to move off the island...rated only for 625hp crank.....I am aiming for some version of mid 500's by 4600rpm....and pulling all the through the range with the next (and final) transition.

Tom. M

Just so you all know, JT and Chuck have put a base system on Chucks car (88 AT S4) which I believe is a 5 psi setup. I'll be pushing them to get it sharktuned and dyno tested because out of all the stuff they are doing, this is the one that will be the most cost effective/easiest to start with. I had this system on my GT..it went on in no time and I ran it for something like 3 years. This was back when we were still playing with the SMT, injector sizes, different breather setups etc... Unfortunately for me, I was dealing with other gremlins that needed to be sorted (t-belt alignment, and tensioner issues) so I took the system off for the time being. The whole thing came off and went back to stock in under a day. Easy on ..easy off..which is nice for those that upgrade their 928's from time to time ...

Wade T

Anyone have a rear mount 16v car? Has it been done?

Tom. M

Well according to the first thread that Randy deleted...Beej was heading that way..but I think that was more of a mock up that got sidetracked.. I would think a low pressure system would work on the Ljet cars the same way Carl's S/C set up does..and the CIS cars should be a no brainer...at least at 5 psi...

Tom. M

Hey Wade..come on down to the shop this weekend..there are lots of turbo parts laying around I'm sure something could be made to fit

89 928 turbo

Hey Wade,

What year is your car? We took and attached the piping and up pipe on Maurice's car to see what he would be looking at for modifications and it fit perfectly...well almost. Two things needed...one was that the rear fender would have to be modified (cut) to accomodate the exhaust set-up and a custome piece for the crossover to the intake would have to be developed.....carbon fibre is wonderful material.

For a basic set up and a 5lb spring it looked like it would work well....I think your car runs on the rich side.

Let me know if you want to come by the shop this weekend and I'll talk to Chuck to make sure he is around....maybe you can join us for a dyno tuning session in Olympia where we are setting up for sometime this weekend and you can look at the whole setup.

Dennis Wilson

Tom,

The CIS equipped 928's will require more work to reroute the intake since the turbo must be installed between the air sensor plate/fuel distributor and the throttlebody. Pressurizing the CIS components will cause an abnormally low control pressure. i.e. too rich fuel mixture.

Dennis

Tom. M

What's interesting is Carl didn't do anything exotic as far as I remember with his first S/Cd 79...and it ran out of the box. His 79 CIS put out S4 numbers way back at the OCIC dyno day..

gruffalo

we're not talking about a group buy, but if we weren't talking about a non-group buy, I would consider getting not non-in on it.

seriously, if the price wasn't not right.

Dennis Wilson

Tom,

Haven't seen Carl's (that I can remember) but I expect he relocated the Fuel distributor/air sensor and lower chamber. Keep in mind that the air sensor plate and piston (in the fuel distributor) are designed to operate in a vacuum. If you pressurize the lower chamber the engineered air/fuel mixture curve is skewed due to the additional upward movement of the piston. This results in a lower control pressure and richer fuel mixture. BTW if you look at other CIS turbo's you'll notice the turbo is between the air sensor plate and the throttlebody for this reason.

Dennis

Tom. M

thanks for the info Dennis. I will dig into Carl's setup a bit more. Plus, like you said..it's not like Porsche didn't turbo the CIS cars...will look at those too...

Dennis Wilson

Tom,

The 930 and 931 were the two Porsche CIS turbos. BTW the race version of the 931 GT used a 928 fuel distributor and two injectors per cylinder (375 hp). Guess running rich isn't always bad.

Dennis

PorKen

(Typical S4 numbers are crap.)

(My '81 with a proper (not too big) exhaust puts down more torque than that, and with '79 cams...)

(My well tuned 86.5 puts out the same numbers as a stage 1 85/86.)

What was my point? Oh, yeah... you can get really good numbers out of a 928, just by getting it back to stock tune, plus a little tweaking. Put another way, many of the stage 1 (turbo)superchargers are basically making up for ineffecient exhausts, or bad tuning.

What's with all these SS/chromed pipes, monster turbos, intercoolers stuck everywhere. Cutting the body? Lame.

What I'd like to see is a CHEAP, I mean Walmart cheap, Stage 1 OB rear turbo that can give a well tuned car that extra edge. Stock L/LH2.2 24# injectors. Cheap turbo. No intercooler. Self contained oiling/cooling. Aluminized steel pipes. You wanna upgrade? Get a Stage 2, fool!

Don't make me get out my welder.