911SC (with CIS to EFI) Turbo Conversion

[tbitz]

Originally posted by cowtown
I'm running a Dynomax 3" in/out on my 930, and it's got a lot of low resonance. I don't think you could shoehorn a bigger muffler in there.

Case Length 16 in.
Overall Length 23 in.
Thickness 5 1/2 in.
Width 11 in.

Off idle it sounds good. It's loud, though.

That's a big muffler. No way I could fit that in there. Problem with my setup is the pipe coming from the right SSI blocks a good portion of where the muffler would reside.

6" round has half the frontal area of the 5.5"x11" you are using.

[A Quiet Boom]

Originally posted by cowtown
I'm running a Dynomax 3" in/out on my 930, and it's got a lot of low resonance. I don't think you could shoehorn a bigger muffler in there.

Case Length 16 in.
Overall Length 23 in.
Thickness 5 1/2 in.
Width 11 in.

Off idle it sounds good. It's loud, though.

Hmmm, just for reference I'm running two of those mufflers in 2.5 inch diameter on my X-pipe exhaust, I don't get a drone but it does have that nice raspy sound that I like, somewhere between a Ferrari and a ricer. Sounds great at full throttle. As for muffler choice why not a turbo style muffler? They where originally designed by GM for the Corvair turbo, have little back pressure, work well with turbos and are available in about any oval size you can imagine. These are extensively used by the V8 crowd so they're also cheap.

[ohecht]

What about one of the Magnaflow models that flows in and out of the same side? Something like the C5 corvette setup, where the flow can be reversed 180 degrees while it is muffled.

Just in case that helps fitting issues or getting extra volume without taking up as much room side-to-side.

Olivier

[tbitz]

You mean like this:

5"x8" oval
2.5" pipe



I thought about it, but it just wouldn't fit in my setup. It's the pipe from the right SSI that is causing alot of the problems. Remember I'm running backdated exhaust, not the stock headers.

[ohecht]

I am trying the same thing with 2 turbos behind SSIs, and the space is even more limited. I would love to be able to fit small (maybe "custom" shortened) versions of something like that you have pictured closer to the corners, like the more recent Porsche TTs. I have to get the turbos positioned first, though.

Olivier

[MichiganMat]

I've seen some pretty creative mufflers on the turbo cars, a buddy of mine has a set of _really_ small ones coming off his turbos, they look like cherry-bombs but smaller. His car sounds like a helicopter when its spooled up.



.. and it shoots fire-balls too. 3.8 liter, twin-turbo, 700rwhp.

m.

[turbo6bar]

Originally posted by MichiganMat
.. and it shoots fire-balls too. 3.8 liter, twin-turbo, 700rwhp.

[/B]

Does your buddy have problems with small birds or single-engine aircraft landing on his rear wing?
jurgen

[ohecht]

I just saw this on Pelican...not my style of exhaust, but maybe the canisters and some of the design features could be adapted to a higher-volume muffler in a tight space with a turbo.

http://www.pelicanparts.com/catalog/images/exhaust/914_monza_pic1.JPG

The whole thing is only $212 from Pelican, and you could probably make 2 exhaust systems out of it.

Olivier

[ohecht]

Tony,

How is the project coming along? Can you tell me the part numbers and where you got the fittings you ended up using the chain covers?

I have my engine out for a new clutch, and I may want to take this opportinuty to install the oil drains in the covers while I have easy access. I assume I could just plug the fitting with a threaded plug or bolt until I am ready to use it without any ill effects...

Thanks,

Olivier

[tsuter]

The oil return to the chain cover is done as follows:

1. Drill a 9/16" hole with a 3/8" NPT tap. Located as far lower right of left cover as possible.
2. Screw in a 3/8" pipe to 5/8" hose straight fitting with thread sealant or teflon tape.
Source - any hardware store
optional but recommended... weld it as well.

If you also relocate the Thermotime switch as well - recommended - then it takes a 31/64" hole with a 14mm x 1.5 tap.

[ohecht]

Is there a fitting that would provide a threaded hose connection? I ask because I may do this modification now while I have the engine out for a new clutch, and then I would cap the connection until needed.

Thanks,

Olivier

[tbitz]

Project is moving slowly. Summers are short here in Ottawa, and I want to enjoy the car instead of having it spend the summer on ramps. I'm also busy with a contract job I got so my time is limited on this project.

For the fitting I basically did what tsuter said. Only difference is I used a nut to secure the 3/8 pipe fitting on the valve cover back. You can see this nut in earlier pages of this thread. I used a 45 degree fitting, but it now looks like a straight barb would be better as the turbo will move to the right a bit.

You can always plug the barbed end with a rubber hose temporarily.

[ohecht]

That's what I was thinking with the hose plug. Maybe a vacuum plug.

Thanks.

Olivier

[mr.bch]

Look at the current Turbo Neons, they only have cats. NO muffler. Sounds tough. Exhaust babble off the gas and all. Pretty neat for a production car. Turbos do a great job of transforming exhaust noise.

[1fastredsc]

Anything new over here?

[tbitz]

No update. I've got a real job which doeasn't leave much time for the turbo conversion.

[ohecht]

Would these work for the fitting?

fitting

I am trying to decide if it is worth having a threaded fitting on the hose end, and if so, which type of thread to have without knowing exactly what line I will eventually use.

Or is this just overkill and I should just use a barbed hose fitting?

I am thinking that the flow would be better with a threaded fitting on each end.

Also, does anyone know a good source for the right tap that is not mail-order? Local hardware stores do not have taps that large.

Thanks,

Olivier

[A Quiet Boom]

A machine tool supply store would have the proper 3/8" NPT tap.

[tbitz]

Originally posted by ohecht
Would these work for the fitting?

fitting

I am trying to decide if it is worth having a threaded fitting on the hose end, and if so, which type of thread to have without knowing exactly what line I will eventually use.

Or is this just overkill and I should just use a barbed hose fitting?

I am thinking that the flow would be better with a threaded fitting on each end.

Also, does anyone know a good source for the right tap that is not mail-order? Local hardware stores do not have taps that large.

Thanks,

Olivier

I'd just put a straight barb fitting and plug it with a hose. Note: it isn't a big deal to do this later when you have all the parts for the turbo conversion. You might as well wait.

[ohecht]

I might do that, Tony...there are still too many options on where the turbos might end up to start drilling holes in my engine, I think!

Thanks,

Olivier