78sc 3.0 Can I add turbo??

kmhemi · 12-10-2004, 06:53 PM

Can you upgrade a stock 3.0 to turbo? Are the camshafts different? What's involved other than money and alot of work?

Lukesportsman · 12-10-2004, 07:02 PM

You sure can. Do a search for this topic, but tricky since you can't use 3.0 or SC in the title. I think his handle was RFNG who was designing a kit. Search Beep Beep and Juan.

Your camshafts will work for moderate boost. Compression will be the biggest issue unless you change pistons. Look at EFI conversions to in that it will give you options outside of CIS.

You have the correct block, crank, and rods. You might consider the 3.2 EFI or Tbitz's or multitudes of other custom fuel managements. It has been done and turns out successful if $$$$.

kmhemi · 12-10-2004, 07:27 PM

what kind of power gains can be found with the stock pistons and CIS if I add a turbo?

beepbeep · 12-10-2004, 07:40 PM

Quote:

Originally posted by kmhemi
what kind of power gains can be found with the stock pistons and CIS if I add a turbo?

~250-260 HP (if you have correct US engine with lower C/R pistons).

It can be easy or it can be complicated/expensive. How handy are you?

kmhemi · 12-10-2004, 07:43 PM

I can rebuild the entire engine with ease if I need to.

dd74 · 12-10-2004, 09:07 PM

You can also supercharge the 3.0.

kmhemi · 12-10-2004, 09:22 PM

Speak ..wise one !!
Did someone say supercharger??
I'm in what's the details?

dd74 · 12-10-2004, 09:55 PM

Do a search on "supercharger," or "Superchargers of Knoxsville." Evidentially, it's a very competent system as long as you are prudent with the boost. They build two units;

1) a Whipple Supercharger, which isn't as torquey and a little easier on your gearbox/drivetrain; and

2) a Paxton Supercharger, which is a balls out torque monster.

Both get the early SC motor, as I recall, over 300 hp. The Whipple is fairly reasonable $$ wise, while the Paxton is about $7K, IIRC.

Either way, you'll have a very strong engine that should last if you don't drag race the car.

Of course, you know about the other liabilities with such modifications, right? I.E. upgrading the suspension and brakes.

MotoSook · 12-10-2004, 10:19 PM

I'm developing a turbo system for the 2.7-3.2 engines...

How soon are you looking to pull the trigger?

DonNewton · DonNewton's Garage

Check out Turbo Performance Center in MD. Mike Levitas does absolute wonders with supercharging and turbos! He also drives a mean race car.

kmhemi · 12-10-2004, 10:30 PM

Not a big rush. It's in the bodyshop now getting a 930 body kit..Sometime next summer would be fine by me. I have a little history with superchargers on V8 engines, Never thought about it on the 911. I just figured turbo would be the way to go since the factory did it and the parts are there.

dd74 · 12-10-2004, 10:35 PM

Yeah, but the factory turbo - at least the 3.0, had 6.5:1 compression, a different block, a big intercooler (later on), and a whole bunch of other stuff. I mean, after all, if you go to a turbo, all you're doing is "sticking" stuff onto an existing powerplant designed within the parameters as it exists in your car. IMHO, very few mods make these engines much better overall.

If I wanted a turbo, I'd try to adapt a true factory turbo engine to my chassis. Or just buy a 930 and be done with it.

beepbeep · 12-11-2004, 03:42 AM

Sorry for not answering before, I just had a biiiig bussines exam. (covering half semester of studies).

First, it's not ordinary "rebuild by the book" skills that are required for this kind of project. It's more ability to be creative and fabricate stuff. If you have acess to good tools (TIG-welder, machines etc.) it can be dirt cheap. Otherwise you have to go to shops and it will cost more.

Second, supercharger usually cost more, is less reliable, more complicated and nets less power. I've went trough reasons many times before, it's all there in archives.

Third: there is not much "true-factor-turbo-with-extra-cheese" on turbo engine. They were built very conservativly, and have been re-done in many ways since first 930 appeared 1975.

If your SC engine is of low C/R type specced for NA market it will be able to take light boost w/o problem.

Again, I advice against supercharger...this is not V8 and fitting supercharger is troublesome and expensive. There are people here who tried and then swapped it for turbochargers. A small turbo that draws air trough CIS and boosts 0.5 bar, plus little lower control pressure should do the trick.

MotoSook · 04:02 AM

The low compression also makes the Turbos lug like a fat pig off boost. I know of an 3.0 that has been turbo charged since the 80's, and it has log a lot of miles...perhaps the owner will see this thread

What you lose in the low boost pressure is made up in the CR of the pistons, so one way or the other, you will have to be wary of detonation. If you had a low CR, you'll be cranking up the boost until you detonate!

There are other guys on this BBS that have boosted 3.0 or 3.2 without having torn the engine down to midify it.

A mildly boosted CIS or Motronic engine is viable. As long as the boost monster doesn't grab you by the throat, the engine will live a long life.

Juan Ruiz started with a stock 3.2, and Richard Fong started with a 3.0 L-jet. Both got very nice numbers out of their engine with approx. 7 psig of boost. Boosting the engine adds very little stress to the engine from a mechanical perspective.

EDIT: As I was typing this, I saw Goran posted

....yep, a tweak of the CIS will make the 3.0 a happy boosted engine

rfng · 12-12-2004, 06:12 AM

Yeah it can be done, 7 psi on a 80-83, 9 psi on a 78-79. I have a completed proto type kit for an SC that I was going to start selling, but the interest was relatively low. The proto-type was done on a 83 but I would imagine it will work on a 78. You would have to remove the air pump as its in the way.

turbo6bar · 12-12-2004, 06:38 AM

Quote:

Originally posted by Souk
I'm developing a turbo system for the 2.7-3.2 engines...

How soon are you looking to pull the trigger?

When will the trigger be ready to pull?
jurgen

MotoSook · 12-12-2004, 08:09 AM

Jurgen,

I'll be fabricating and testing over the winter. I'm targeting April or May for final testing in the cars and dyno runs. Hang tight, unless I go bankrupt, I'll have a few induction, ignition and fuel control available.

tsuter · 12-12-2004, 08:14 AM

Quote:

Originally posted by kmhemi
Can you upgrade a stock 3.0 to turbo? Are the camshafts different? What's involved other than money and alot of work?

Yes, no and less money than work.

Most of the details are here:

911SC Turbo

air-cool-me · 12-12-2004, 02:25 PM

looking back on several turbo thread's i failed to notice why more people didnt go with the exhaust manifolds from the turbo, they are cheap!

is the turbo placed too low? do you need a scavange pump?

things not line up?

do they flow bad?

Lukesportsman · 12-12-2004, 03:17 PM

Flow is not optimal even before cat's. They end up longer than ideal before the turbo housing. Many people often are looking for minimal turbo lag in custom installs and the factory pipes/turbo setup is not optimal in today's tech in reducing lag or ultimate flow. They were designed around certain criteria and did well for their time within this.

They are cheap and would seemingly make it quicker/cheaper to convert. I differ from an earlier post in that I think WE can do it better than it was done so many years ago and we can improve these engines. We don't have the constraints of mass production, emissions, and limited tech that Porsche was limited to back then. Yes they had/have great engineers. But, we have learned from them and improved over 30 years of Turbo Porsches. Porsche didn't design a Turbo in 74 and stop developement did they, nor need we.