Hi everyone,
I have an extra 964 intake plenum and I was wondering if there is any advantage to using it on a 3.4L (based on an '86 3.2L), twin plug, 10.5:1CR, stock head motor that's not going to turn more than 7000rpm.
I'm not asking whether it would fit. I realize that I'd need to use adapters to bolt it to the heads and I realize there would be some programming involved for the switchable chamber thingy.
-Chris

 

There is an advantage in running that system, I suspect that the 3.2 manifolds hit a flow limit at approximately 270-275bhp and will not allow more power. I have been considering the same conversion on a 3.5 single plug that we have in the shop on stock manifolds at 275bhp/270lbft and strangely another potential customer has the same power with a 3.5 twin plug at 275/255. If you do fit the 3.6 plenums, be sure to smoothly taper the adapters from the 41mm bore of the plastic runners to the 39mm of the heads, do not open the heads out to match. You should aim to actuate the resonance flat at around 5500-6000 on full load, best to determine the actual crossover with two dyno runs, one flap open, one flap closed. I would be very interested in your results if you go ahead so keep in touch.

 

Thanks Colin,
It will probably be a winter project thing. I'm running stock heat exchangers (it's a street motor)so I won't be seeing 270hp any time soon.
-Chris

 

If your interest in selling you 3.2l intake manifold if you convert it, lmk thanks ken

 

I won't be doing this project for a while but I emailed a friend of mine who has a 3.2 intake he's not using and told him to look here.
-Chris

 

Follow up to previous post:

The 3.5 single plug engine is now in the shop for a Motec conversion to replace the troublesome BWE injection, and at the same time I managed to persuade the owner to let me try a set of 964 intake manifolds. We have just finished machining up the adapters and should have the engine running in the next 2-3 weeks. I'll keep you posted with the results but I am quietly optimistic.

 

Colin, aluminum or plastic 964 manifold? I have seen some improvement on turbo engines by using the either compared to the 3.2 Carrera. Most noteably is the effect the resonance flap has.

 

Plastic.

 

Hi Chris:

LOL,.......This conversion works VERY well,.....

Go for it.

 

Quick update:
Intake manifold stubs made & fitted, resonance flap plenums fitted, throttle body modified for TPS & custom throttle linkage made, MoTeC loom made and ready to fit. Just waiting on a couple of gearbox components (also having a freshen up) and the engine will be in next week.

Can't wait to see what this motor will do!

 

Colin, would you post a picture?

 

I'll take some photos tomorrow and see if I can post them.

If the conversion is successful we are already looking into producing a custom Alpha-N conversion box for the 3.2 Motronic that includes the rpm trigger for the resonance flap, thereby allowing the use of the manifold without the expense of running with Motec or similar.... I would think that a set of 964 cams, 964/993 manifolds and Alpha-N would probably give the lowly 3.2 a new lease of life.

 

Here is the 3.5 engine with the manifold fitted, tucked away in the corner of our development shop. The car it is going into is the white/rubystone 2.7RS replica seen in the background.

For reference the amethyst 964RSL in the middle has our MoTeC +1 conversion and is posting 348bhp/311lbft at the flywheel or 317bhp best at the tyre; the guards red 964RS CS in the foreground has a basic MoTeC conversion for "just" 328bhp/300lbft & 295bhp at the tyre, however its carbon doors/fenders/bonnet will no doubt make up for the deficit.

 

Interesting

 

Interesting