911SC Turbo Conversion?

[911TT33]

Hi all,

Got a fellow Porsche friend with a nice tight 911SC who wants to turbo his motor with a low boost setup.

Any of you guys done this before?

The 3.0 motor runs 8.5:1 C/R, so I guess it should be fine with approx 10psi boost using a bolt on setup?

Got a few questions:

1. Would 930 style headers bolt onto the SC motor?
2. What fuel enrichment options are there for such a setup? I've heard no extra fuel mods for low boost?
3. What about ignition timing for this setup? I've heard stock ignition timing for low boost?
4. What should one do to strengthen the motor? Aftermarket fasteners/studs?

Thanks!

[jcc911]

Lots of info on this posted here. I just finished the conversion myself.
Yes 930 headers will work.
My car runs fine with the SC pump, but you need to check your fuel pressures first.
Depending on your setup, you really should dyne tune to set the best timing. The death of turboing a car is detonation so you need to monitor the AFRs when tuning, as you want to make sure you don't go lean under boost.
Typically headstuds are an issue, you want to make sure they are intact, but would recommend replacing those.

With out a large intercooler, meth inj, etc. 10 psi might be too much. 0.4-0.5 bar is much safer with the stock c/r.

[jcc911]

Although my car is running well with the SC distrbutor, I am looking at other ignition options so I can retard on boost.
Good luck!

[quattrorunner]

Do a search. It's been done successfully. Make sure the engine is healthy and have fun.

[sjf911]

Originally Posted by 911TT33

Hi all,

Got a fellow Porsche friend with a nice tight 911SC who wants to turbo his motor with a low boost setup.

Any of you guys done this before?

The 3.0 motor runs 8.5:1 C/R, so I guess it should be fine with approx 10psi boost using a bolt on setup?

Got a few questions:

1. Would 930 style headers bolt onto the SC motor?
2. What fuel enrichment options are there for such a setup? I've heard no extra fuel mods for low boost?
3. What about ignition timing for this setup? I've heard stock ignition timing for low boost?
4. What should one do to strengthen the motor? Aftermarket fasteners/studs?

Thanks!

930 headers fit fine. I don't see how you could possibly run 10lbs of boost without serious fueling mods. The stock fuel pump easily handles the HP at EFI pressures (I have about 300-310 at the wheels with a nominal 2.5 bar fuel pressure and stock CIS pump) but I don't know about CIS especially at 10lbs which is almost 930 territory which runs 2 fuel pumps.
Timing is one key to minimizing destructive issues but impacts performance. I am actually seeing some sub-audible detonation with my car at only 0.6 bar with meth and an intercooler trying to run a little more aggressive advance (17-18 degrees with twin-plug).
I think the biggest weaknesses associated with this change are inadequate stock oil cooling, inadequate oil scavenging provisions, risk of piston failure from detonation, inadequate control of timing, transmission failure from excessive torque, clutch failure, inadequate brake capacity, and suspension. Then, of course, there is the problem of having more horse power than you need but it never being enough.

[911TT33]

Thanks guys.

So 0.5 bar / 7psi can be run safely with no fuel/ ignition mods, or intercooling?

What kind of power can one expect from such a bolt on setup?

I know the 3.2 bolt on turbo kits net great power output. Just wondering how the SC compares?

Jeremy, have you looked into the MSD ignition unit with ignition retard? It can retard ignition from 0-3 degrees per psi of boost. Might be a good solution?

[quattrorunner]

The ones I remember made like 230-260hp. Depending on a few differences

[guru944]

911TT33;

Good project...
Also recommend MSD6BTM, very reliable.
Low boost pressure 0.5bar (7psi) is safe. Intercooling a must and no methenol.
Engine Oil cooler also a must (bigger is Better) and Quality Synthetic Oil like AMSOIL a must.
PM me if you need anything..
and Keep us posted
Later...

[jcc911]

I have not yet, my heads are twin plug, but haven't decided how I am going to fire them yet. A bolt on kit will easily add min 50 hp

[DSPTurtle]

Have you considered an SC instead of a turbo? SC makes much more linear power. I think my next project might be to SC a P-Car.

[911TT33]

Don't like superchargers... they rob power to make power. Too much parasitic losses.

My friend wants to go the turbo route because he'll end up rebuilding the motor down the track for more boost and fit EFI etc...

[DSPTurtle]

I respect your friends desire to go with a turbo. But, I must admit, I was in the same boat a few years ago. I thought that SCs were wasteful. That is until I put one (twin screw) on a bone stock Mustang and went from 303hp to 479hp (at the wheels) with no other mods. I have both turbocharged and supercharged cars. The turbo is more "exciting." The SC is more powerful but "boring." It has intrigued me enough to want to try it on a P-Car. 9psi should be a good option.

[jsveb]

try and do a search for the user "tsuter" - I think that was his user name.
That is one of the oldest and comprehensive threads on this.

Good luck

[911TT33]

Thanks, will do. Maybe if we keep the boost to 0.5bar, all should be good.

[jcc911]

Here is a good start, and a great price!!
Porsche 911 930 Turbo Headers Exhaust Manifolds | eBay

Think you will need to swap out the exhaust studs though for longer ones as these look like thick flange.

[jcc911]

I am running 0.5 bar with out issue, and might take it up a point or two with twin plug and more fuel but will see what that does to my AFRs.

I posted my conversion here as well, there is some good info.

[5.7 GT1]

You maybe interested in these parts I have for sale most of what you need is there. I have just about all you need less the 930 lower intake. Let me know if you are interested. Here is the link: http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/636668-fs-930-parts.html

[iamchappy]

Slippery Slope, this SC engine started out as a 79 3.0 now it's a 3.1

I drove my turbocharged 3.0 engine for a few years with a refitted BAE kit, MSD BTM retard ignition and a 7th injector for enrichment. I ran 9lbs of boost on the street.

All you will ever need to know on this thread.
I can send you a PDF of the BAE manual.

http://forums.pelicanparts.com/porsche-911-technical-forum/90065-911sc-turbo.html

[jsveb]

Iamchappy, I have followed your build since I joined PP.

Man it is sweet!!!

I have got a 930 cis, less wur. I'll sell it cheap. The injectors are cleaned and tested.

[iamchappy]

I remember you Jesper, how are things with you...