3.2 intake or orignal flat for EFI

[spjuvern]

I have finally decided to go for EFI in my 965
and wanted some inspiration.

And what is the best way to go,
keep my ported flat intake manifold 36mm and heads will still be 36mm with Turbokraft blocks for small volume
or go with the 3.2 manifold but adapters from 42-36mm ?
i enjoy building and manufacturing so that is not a problem.
car is mostly used for trackdays with 550hp


i have search and read some old treads about it most people seems to recommend the 3,2 manifold, but wonder if there is any new thoughts about this today

what does owners here feel and maybe some have tested in both configurations?

And how about the ignition what is the best way?
using a 964 RS flywheel with 60-2 insteed of my patricmotorsport light flywheel for ez69
and is there always a benefit with COP even on a 550hp engine?
if so what kit is best to use?

[spjuvern]

[RSR Racer]

IMO, 3.2 manifold hands down. After dynoing a 3.5L twin plug engine back to back with the flat manifold and the 3.2 manifold and watching the EGTs on every cylinder, the flat manifold has some pretty big issues. Cylinders 2 and 5 run very lean and we needed to trim the injectors over 20% -25% to bring the temps inline with the 3.2 manifold. The more boost, the more we needed to enrich those cylinders (running Motec EFI).

Also, when we broke the engine down with the flat manifold with euro CIS, the rings in 2 and 5 were shattered (even the oil rings) and the ring lands and piston crowns trashed. I would only use the flat manifold on a very mild build and even that is a bit worrisome.

We had none of those issues with the 3.2 manifold.

Piston #2 with the flat manifold on a 400+ HP build:



and piston #5:



Yep, all the pistons went in the trash....

I'm sure there a lot of folks here who know way more than I do but....I will not be using a flat manifold on any future builds. My outlaw 930 still has the flat manifold but, it is barely at 400 hp and is running pretty rich on boost thanks to my adjustable WUR and a lot of test runs with fuel pressure gauge and a lambda gauge..

Anyway, just my $0.02. Good luck!

[mikedsilva]

Originally Posted by RSR Racer

IMO, 3.2 manifold hands down. After dynoing a 3.5L twin plug engine back to back with the flat manifold and the 3.2 manifold and watching the EGTs on every cylinder, the flat manifold has some pretty big issues. Cylinders 2 and 5 run very lean and we needed to trim the injectors over 20% -25% to bring the temps inline with the 3.2 manifold. The more boost, the more we needed to enrich those cylinders (running Motec EFI).

Also, when we broke the engine down with the flat manifold with euro CIS, the rings in 2 and 5 were shattered (even the oil rings) and the ring lands and piston crowns trashed. I would only use the flat manifold on a very mild build and even that is a bit worrisome.

We had none of those issues with the 3.2 manifold.

Piston #2 with the flat manifold on a 400+ HP build:


and piston #5:



Yep, all the pistons went in the trash....

I'm sure there a lot of folks here who know way more than I do but....I will not be using a flat manifold on any future builds. My outlaw 930 still has the flat manifold but, it is barely at 400 hp and is running pretty rich on boost thanks to my adjustable WUR and a lot of test runs with fuel pressure gauge and a lambda gauge..

Anyway, just my $0.02. Good luck!

wow, that's some very useful info there.

[mepstein]

We are using a 3.2 intake and Motec on this TT build.

[spjuvern]

How about the 964 intake?
Anyone here has experience with it on a turbo engine?

https://islandworks.se/products/islandworks-turbo-intake-conversion-kit

[fourblades]

"Cylinders 2 and 5 run very lean and we needed to trim the injectors over 20% -25% to bring the temps inline with the 3.2 manifold. The more boost, the more we needed to enrich those cylinders (running Motec EFI)."

Do you have a table for one of the cylinders you can share?

Thanks,

John

[David]

I have no experience not using the Carrera intake but wanted to add that I machined my 930 heads to match the Carrera intake. I set them up in a mill and machined a taper from the existing port to about 40.5mm at the flange.

[Tippy]

Originally Posted by spjuvern

How about the 964 intake?
Anyone here has experience with it on a turbo engine?

I couldn't get my IC to fit as they sit too tall on a Carrera 3.2 without heavy modification.

Beware.