Lance J

thinking of boosting my 79 cis shark with a rear mount turbo setup. Is it true that the cis plate will meter up to 8psi of boost. I only plan to run 6psi max. I don't want to ditch the cis just yet its in fine working order. and if i wish to run more boost i will fit an Rpm & boost based Meth/water injection system. with Low compression i fill if i use other tricks to fight knock/denotation. Also with 350 rwhp as my goal how important are bolting on euro TB, Heads, headers are at this time.

1) What size and model turbo would be good not as to choke the engine?

2)how much boost safely can be ran with just bolt on turbo and not tuning setup?

3) Dont be shy tell me if i should just dump the turbo idea and install 150hp nos and be happy!!

Note: I would go Supercharger way via carl's kit but i need A/C i live in Vegas 120 plus in the summer

karl ruiter

I'm pretty sure you retain the A.C. with car's kit.

atb

The local rear mount turbo guys were looking into doing this mod. If I recall correctly one of the stumbilng blocks is finding room for the up pipe. On the S4's there's room between the driverside firewall and the motor, but I guess this is not the case on the 16v motors. Take a look and see if you see any room for it on your 928.

Imo000

I'm pretty sure all the popular SC setups leave the A/C intact. There are only a few, including mine, that have the SC in place of the A/C compressor.
If you are only running 6-7psi, you don't really need alcohol injection or intercooler. Anything above that will start to require it.

hacker-pschorr

Sweet, more OB lovers

I won't go into boosting CIS since I'm trying to only say nice things around here (new years resolution).

Carl's kit does not lose the A/C unless he changed it recently. His setup in overall layout is similar to the one on my 16V (Murf Kit) and I have A/C.

Whichever way you go, keep us posted!!

IMO,
About the intercooler - normally I would agree, unless he has a higher compression Euro motor (versus a 78-79) and he's in vegas.
Some claim the rear turbo acts like a small IC - until I see intake air temp readings with a known good sensor / gauge (most used for this purpose are not accurate) the jury is still out. In theory it sounds good.

Lance J

i just wont be lowering the car anytime soon just in case i have to take a different route to make it fit. who are the local rear mount guys???

Lance J

i have an back up plan to go EFI....after reading that MS conversion thread got me fired up. i will start mounting sensors anyway just to keep an eye on things

Lance J

my 79 is a USA model so the dog low compression is what i have...your right hacker stick to your resolution because i just my go the Nawwhhhhhhs (nitrous) route, if i hear any thing negative about adding power to an OB. Its just something about spending tons of time and money to get the car sound then selling it because the lungs are to small...I have an OB. chip on my shoulder.

atb

Do a search for Rear Mount Turbo or RMT, and some of their stuff should pop up.
Their latest dyno run was around 620rwhp.

hacker-pschorr

Don't let anyone tell you an OB isn't worth a power increase:
https://rennlist.com/forums/928-foru...omparison.html

100% stock 79 with headers and open exhaust. AFAIK the ignition timing is set to stock and so is cam timing.

Now don't go getting the guys hopes up. 620rwhp in his car would take about 40psi

Lance J

well on an 2.0 mitsu evo it only takes 36 psi

hacker-pschorr

Evo's start to get interesting closer to 800rwhp

atb

Yeah, and then it makes what, all of 47 ft/lbs. of torque?
(You know I'm kidding right?)

Lance J

i wont tangle with a stock one right now i'll get spanked.

dprantl

Do it! That will be one cool car, CIS rear-turbo. Or do MS and then the FI kit. Then you can blow that stock Evo away. Kinda like I did a few days ago with a brand new M3. That guy was so mad later at a red light, it was hilarious!

Dan
'91 928GT S/C 475hp/460lb.ft