SSI's on a 3.6 question

uwanna · 08-02-2009, 08:07 AM

I have a '80SC with a 3.6 transplant motor. At present I have thick flange HE's from a 3.2 on it. Been thinking of installing SSI's and have found some from an '80s SC. Will they fit AOK. I assume if the 3.2 HEs bolt on, these should as well. I know they make SSIs for a 3.6, but wonder what the difference is from the 3.0 and 3.2. Perhaps exhaust port size?' I know I need new oils lines to allow the fit.
Regards,
Grant

cdrik915 · cdrik915's Garage

Regarding SSI , the inlet diameter of 38 mm is normally too restrictive for 3.2 or 3.6 , reason for what serious upgraders prefers using real headers with 40 mm diameter or more.

The difference is located on the exhaust port size only.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by uwanna

I have a '80SC with a 3.6 transplant motor. At present I have thick flange HE's from a 3.2 on it. Been thinking of installing SSI's and have found some from an '80s SC. Will they fit AOK. I assume if the 3.2 HEs bolt on, these should as well. I know they make SSIs for a 3.6, but wonder what the difference is from the 3.0 and 3.2. Perhaps exhaust port size?' I know I need new oils lines to allow the fit.
Regards,
Grant

They can be bolted on, at worst you will need to install shorter studs, The issue is that there are no SSI's that are correctly sized for a 3.6, they all have 1.5" OD(1 3/8" ID) primarys, this is ok up to ~4k rpm but severely restricts performance beyond that.

1100sport · 08-02-2009, 08:45 AM

Salut Cédric
Inside diameter of SSI is 35mm (the outside is 38mm), same as OEM early exchangers. It is indeed too small for engine with displacement above 3.2l (included).
Mathieu

uwanna · 08-02-2009, 09:30 AM

Guys,
I already have 3.2 HEs on this motor, so I already have the port restriction problem already, right? Even with what I have, this car runs like a rocket! To my thinking the SSIs have got to be better than what I already have. SSI shows a 3.6 application, are they also smaller ports? That would be strange if true.

RarlyL8 · RarlyL8's Garage

SSI does not make heat exchangers for the 3.6L engine. They may fit but they are not designed for 3.6L capacity. As stated above, all SSI exchangers have 1.5" primaries.
Ben and I are working on a solution for that application right now. They will include heat exchangers.
sneak peak of new headers

Elombard · 08-02-2009, 10:06 AM

I would go with used 993 HEs with the flanges flipped.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by 1100sport

Salut Cédric
Inside diameter of SSI is 35mm (the outside is 38mm), same as OEM early exchangers. It is indeed too small for engine with displacement above 3.2l (included).
Mathieu

1 1/2" = 38.1mm
1 3/8" = 34.925mm
not to nit pick but the SSI are actually sized in US pipe

Quote:

I already have 3.2 HEs on this motor, so I already have the port restriction problem already, right? Even with what I have, this car runs like a rocket! To my thinking the SSIs have got to be better than what I already have. SSI shows a 3.6 application, are they also smaller ports? That would be strange if true.

Yes, you alrready have a restriction, but the SSI's will not alleviate that issue. Imagine how it will run w/ a properly sized exhaust. Where ever SSI are listed as for 3.6 it only means that they can be bolted on, they all have the same pipes.

Correctly sized headers will be ~ 1.75" OD( 1.625" ID)(~44.45mm/41.275mm for the metristas) 3.8 Cup and 3.8 RSR headers were 42mm(that's from my poor memory but I think it's correct and I'll look it up if it's important to anyone)

Currently if you need heat B&B and Fabspeed make good headers for this app 993 headers are good too but are tougher to use from an installation labor perspective,

If you don't need heat I like the stepped headers, but the currently available versions aren't that much better than B&B or Fabspeed versions, especially when muffled.

Elombard · 08-02-2009, 10:45 AM

You live in Atlanta you dont need no stinking heat.
Ebay Headers and supertrapp...step up :-)

Zeke · 08-02-2009, 02:09 PM

Ideas appreciated for high volume, large mass mufflers that will contribute to this set up and yet be civilly quiet.

JonT · 08-02-2009, 03:39 PM

993 headers are the way to go. Cheap and several muffler choices.

zzwhm · 08-02-2009, 05:35 PM

Here's a link to a thread on the engine building forum with recent dyno comparison of SSI to 1 5/8 headers on my 3.2. Underscores the advice for larger pipes.

Sneak Peek of New Stainless Steel Headers

PcarPhil · 08-03-2009, 03:27 AM

Just a FYI...I've got a set of M&K flipped 993 HE's with M&K muffler available for sale in the classifieds:

FS: M&K flipped 993 heat exchangers and M&K 993 2 in 1 out muffler for SC/Carrera

cdrik915 · cdrik915's Garage

Quote:

Originally Posted by 1100sport

Salut Cédric
Inside diameter of SSI is 35mm (the outside is 38mm), same as OEM early exchangers. It is indeed too small for engine with displacement above 3.2l (included).
Mathieu

Yes , absolutly right.