Newer large tube SSI questions

[Chris Pomares]

Here is part of the induction side of the engine. Full 41/46 MFI from TRE should show up in the next 10 days.

[Rick Cabell]

Are these new production?

[Chris Pomares]

Yes they are.
The stacks look like short stock MFI but have a RSR like bore and can use the factory air cleaner. It will be a sleeper I hope. And look similar to the engine we sold out of the car.

[glaverbel911]

I just spent about 30 minutes on the phone with Soren Breinholt at JP Group. Here is what I learned.
The 91.936.SSI"s will work on 3.0SC heads. 41mm at the flange and 38 mm ID. They are limited to about 250 hp.
If you want to make more power they will have new SSI's comming out May or June. 91.911SSI41. These will have 41 mm ID tubes and are good for 275 to 300 hp. There is only one guy there at this time building this 41 mm ID exchanger.
Hope that helps.

Im very skeptical of this claim of power limits. The restriction is not the header.
Going too big will alter your exhaust pulse tune and slow down the exhaust gas speed dramatically reducing torque and hp other than at peak. Honestly They should be scrutinizing their mufflers better.

Tuning a motor I go opposite and as small as possible until there is noticeable restriction .
On our 2.2 race motor with DC60s I dropped the primary tube smaller than factory to 34mm ID. We are currently just below 270hp @8300 and have a very flat powerful torque curve.
I’ve only seen negatives with overly aggressive sized pipes.

I Look forward to hear your reports.
Regards.

[Rick Cabell]

At 8300 that engine must be singing a nice song….. I remember Mr. Ruf telling us his favorite early engine was a 2.2.

[glaverbel911]

Ricky. She sings extremely loud music till 8800 that
the concrete crumbs pop off the walls during bench tests.

The 2.2’s are my favorites as well. This one is 2247cc

[Chris Pomares]

We’re not looking for the bleeding edge of RPM. 7000 will be the upper limit.
Time will tell if the 41’s lead to a nice drivable engine. If we get 230 to 250 hp we will be happy.

[Chris Pomares]

https://www.youtube.com/watch?v=r-Mb5DsSUv8

[Chuck Miller]

Thank you Chris !!!!

[Chris Pomares]

Here are pictures of the install. We only had to put a slight dimple at the bottom rear of the passenger side cam tower. That's it.
The tranny gets C, GA, O, V, ZD. Wavetrac, all new synchro's, all new dog teeth, aluminum main shaft plate, intermediate plate and side plate.
.