SSI's with Supercharged 911?

kdubb · kdubb's Garage

I have a Supercharged 3.2 and wanted to know if SSI's would help to increase power to the engine. I have read the many debates (discussions) regarding SSI's and "normally" aspirated engines, but how about supercharged or turbo engines?

Thanks

KobaltBlau · 09-01-2005, 10:19 AM

Here is the problem. your engine, with the supercharger, probably flows at least as much air as a 3.6. SSIs really ought to be made in a larger primary size, but they aren't, so people generally recommend against SSIs on a 3.6, because they aren't big enough. In your situation, something like B&Bs that have a larger primary than you would usually use for a 3.2 would be a good bet. unfortunately, they are expensive. It might also be possible (and cheaper!) to use 993 heat exchangers, but I have no experience with this project.

Turbos are another matter because the turbine has to be hooked into the exhaust of course. I have seen systems based on the HEs that came stock on your car, but the outlet locations of SSIs don't make it that easy to place a turbo. Also, exhaust systems not designed for a turbo may not stand up to having a turbo attached downstream. The turbo question is really a different application than your supercharged setup. Neat looking engine, btw.

Cheers,

kdubb · kdubb's Garage

Thanks for the information. I have heard about the 993 setup before. What is the diameter of the 993 HEs? Has any one installed this application on a 3.2?

martin_gibson · 09-01-2005, 10:44 AM

Have seen these 3.2-3.6 manifold adaptors at http://www.protechnik.com/custom.html but have no idea if they will work?

Rgds

Martin Gibson
83 SC 3.6

kdubb · kdubb's Garage

No I have not. Thanks for the link. I will look into that.

kdubb · kdubb's Garage

I just spoke to the people at protechnik. The adaptors are for intake, not exhaust.

martin_gibson · 09-01-2005, 11:57 AM

Good point!

Maybe you could rotate the cylinders through 180 - they would definately fit then?

kdubb · kdubb's Garage

I may have to stick with the SSI's, or B&B

martin_gibson · 09-01-2005, 12:10 PM

Sorry - my British sense of humour got the better of me!

Good luck

kdubb · kdubb's Garage

No problem....I did lol

KobaltBlau · 09-01-2005, 03:10 PM

Sorry, had I responded quicker I could have told you those were for the intake.

It sounds like what is required to fit 993 HEs to a 3.2 is to turn the flanges, and you will need to custom make a muffler setup, it will be hard to fit a catalytic converter (but the cat bit is also true with SSIs). I searched for some relevant threads for you. Be aware that several people are using 993 HEs on 3.6s in older cars, but they don't have any issues fitting them to the heads. These threads refer to 3.2 based motors, though:

tyson suggests them to catca:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/235603-help-me-pick-cam-post2062720.html

tyson says he did some on his 3.2:

What brake upgrades to do?

steve@rennsport opines that it's a waste of time:

What brake upgrades to do?

If you don't know, tyson schmidt and steve@rennsport are some of the most respected people on this board, so there are experts on both sides of the issue.

On the other hand, used 993 heat exchangers aren't that expensive, so you can pick some up, try them, and if they don't work probably resell them without losing any money. I think the 2-bolt flange is oriented differently on the 3.6s but it sounds like turning the flanges on the exchangers is possible.

kdubb · kdubb's Garage

Thank you for all of the information. I will look into this before I decide which way to go.