Turbo induction setups
 

I have not been very active on here in a while because I'm working on a VW project but have been throwing around some ideas in my head for the 1988 930 slant conversion I have that is in need of an engine job. It is a very nicely done conversion with what I think are OEM steel slant fenders and it has the OEM headlight operating mechanism. Anyway my desire has always been a twin setup but the problem always comes back to the muffler problem, I don't want zorks. I'm looking at some creative ways to deal with that.

I've also been tossing around an out of the ordinary induction setup which is a cross between ITB's and the typical 3.2 single TB manifold setup. My thought is an individual plenum for each bank but instead of ITB's I would have a separate appropriately sized TB for each plenum. So you get better the better flow and response of ITBs but w/o the complexity and idle control problems of the ITB's. Of course the plenum sizing and runner design is all critical. Crazy?, probably but would like to hear some comments.

Ferrari had the same thoughts for what it's worth. 488GTB
http://forums.pelicanparts.com/uploa...1541949438.jpg

When contemplating intake and exhaust designs I spend some time on the www.burnsstainless.com site to get ideas on what tubing and muffler shapes are available.

move oil tank forward, put turbo's next to engine like ruf/stock 996 or 997 turbos, run any muffler or exhaust you want. simples

Exactly what I'm building but it'll be quite a while before I'm done.

Ken - I thought you are using ITBs?? Are you now doing twin TB's?

clutch-monkey - I'm aware of the side mount turbo option, I was hoping to be able to keep them rear mounted though plus have a muffler. May not be possible though unless I want to get into some serious hacking and re-engineering of the tub rear cross member and engine hanger.

David - Yes, I've looked at the Burns site several times, lots of good stuff on there.

Where do you plan on putting the TB's? On the ends of the log, or somewhere the middle like the Ferrari?

No it's twin intake plenums feeding the itb's I didnt see that the ferrari one was two throttle bodies. But my intake plenums will be similar.

"Where do you plan on putting the TB's?"

From a packaging standpoint the easiest would be on the front ends with an IC flow of back to front. The plenum design and distance between the TB and plenum becomes critical to avoid starving cylinders 1 and 4. The side entry like in the Ferrari helps improve on distribution in the plenum but the packaging becomes more challenging on these cars with a full bay air to air.

Then there is the design that Audi used on their LeMans wining R8's to optimize distribution in the plenums.

http://forums.pelicanparts.com/uploa...1542108137.jpg

Transition from the tapered cone part to the actual "plenum" looks like it goes through a long, flat and thin velocity-stack. Nice way to smooth things out into laminar flow before it hits the individual runners.... pretty slick and compact. Easy to produce though? Well....

I have done dual-plenum intakes twice, one of them was with ITB-s. Also doing it for the twin-turbo 2.5 911 engine...

http://forums.pelicanparts.com/uploa...1542202509.jpg

http://forums.pelicanparts.com/uploa...1542202509.jpg

Also doing it for the twin-turbo 2.5 911 engine...

Got any pics? ITB's or twin TB's? If done right they result in a fairly even pressure profile in the main plenum. Much better than just sticking the TB at the end of a single plenum.

http://forums.pelicanparts.com/uploa...1542243083.jpg

http://forums.pelicanparts.com/uploa...1542243121.jpg

http://forums.pelicanparts.com/uploa...1542261151.jpg

Old MODE ITB. Fwiw.

Not a lot of room back there when a fan is needed.