Rothsport ITB 3.2 new build

[DeltaBravo]

,any chance that would pass cali emissions?


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[kenikh]

Originally Posted by DeltaBravo

,any chance that would pass cali emissions?


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Sniffer, easily. But CA requires a visual inspection, so NO. Not even with Cats.

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[sp_cs]

Originally Posted by rsscotty

We built a 3.4 with different cams and exhaust, same comp ratio and cylinder heads that made 310 hp @ 6500 compared to this engine 270 @ 6100.



The 3.4 torque 232 ft lbs @ 4100

3.2 torque 210 ft lbs @ 4100



The upper range of torque 3.4=258 ft lb @ 6300

3.2=222 ft lb @ 6300

Those are superb figures - my 3.4 with dc20 and the standard exhaust hit 270bhp/245 lbft after a live remap. I'm now moving to a 3.5 via a Gt3 crank, William Knight cams, ITBs and 993 plastic plenum. My main restriction will be the SSIs however i hope to match your figures

[rsscotty]

This is the look after all the painted pieces arrived.

['76 911S 3.0]

Work of art!

My only question is why was there no SCL on the ends of the shrink at the connector ends? The glue lined shrink helps to resist water infiltration into the harness that heat shrink alone will not prevent. Just food for thought.

[Canada Kev]

Originally Posted by rsscotty

This is the look after all the painted pieces arrived.

Oooo, pretty...

Originally Posted by rsscotty

We built a 3.4 with different cams and exhaust, same comp ratio and cylinder heads that made 310 hp @ 6500 compared to this engine 270 @ 6100.

Scott, you say you used the same cylinder heads on the 3.4. You didn't go twin plug?

[jmz]

OK, I think I want one. Nice looking hardware.

How does that plenum work compared to something like Borla or PMO itb?

Could it be adapted to my hot rod 3.0 with TWM ITB Stacks
with Elgin Mod S cams? ...just curious is all.

[jmz]

OH, We need a sound clip too.

[Charles Freeborn]

Beautiful work as always.


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[SoCalSK8r]

Originally Posted by rsscotty

This is the look after all the painted pieces arrived.

Wow, wow, wow


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[gwag]

Really nice work.

Is the resonance plenum 'passive', ie does it work simply by its geometry/shape??

Or does it have active valves that open and close??

If it is active, what controls the valves?? What program??

[rsscotty]

The resonance plenum is functional and programmed by the Motec M84 auxillary output function based on engine rpm. They typically switch between 5100 and 5500 on this particular intake and are tuned on each engine for the best power and least disruption of the torque curve. Inside the smaller cross tube (in the center) is the butterfly, which is either open or closed depending on rpm.

There is a vacuum canister which is a OEM 964 part and I use an OEM vacuum valve along with a Pierburg 993 style switching valve.

[Canada Kev]

Is that the vacuum canister beside the air filter?

[Tremelune]

Very cool. I'm surprised it's not done on more ITB setups (although who doesn't love those stacks).

Is there room to change that air filter without pulling the motor? Is there less room for a filter facing forward? I guess it interferes with the decklid, or perhaps there is turbulence by the fan?

[rsscotty]

The air filter is easily removed with the engine in the car.

On our Spec 911 race cars we have the filter facing the rear as the race deck lids have clearance for the air filter.

[rsscotty]

Originally Posted by jmz

OK, I think I want one. Nice looking hardware.

How does that plenum work compared to something like Borla or PMO itb?

Could it be adapted to my hot rod 3.0 with TWM ITB Stacks
with Elgin Mod S cams? ...just curious is all.

The Borla/TWM throttles and the PMO throttles are too high to fit the 964 intake into the engine bay, so this setup may only work with the Jenvey ITB.

[sp_cs]

I wanted to ask about the K&N filter, having read some mixed reviews of K&N/paper filters generally, versus say, foam filters.

Has your testing proven they're the best product, if so based on what criteria?

[rsscotty]

Jeff, the owner picked this particular filter when he initially designed his system and also works on our GT3 intake system for larger engines.. It is always available and fits his space requirements. This filter seals well and we never find any particals inside the intake or engine. This filter also cleans well at the service intervals.

The foam filters we have used on our stack engines are OK when new, but they are a pain to service, they deteriorate with time, and they don't seal well to the intake and let too much debris in.

[rsscotty]

Originally Posted by Canada Kev

Oooo, pretty...





Scott, you say you used the same cylinder heads on the 3.4. You didn't go twin plug?

No twin plug on the 3.4

[sp_cs]

Originally Posted by rsscotty

Jeff, the owner picked this particular filter when he initially designed his system and also works on our GT3 intake system for larger engines.. It is always available and fits his space requirements. This filter seals well and we never find any particals inside the intake or engine. This filter also cleans well at the service intervals.



The foam filters we have used on our stack engines are OK when new, but they are a pain to service, they deteriorate with time, and the don't seal well to the intake and let too much debris in.

Cannot argue with that and thank you for your detailed responses - they're really appreciated.

I shall email Jeff now re the intake parts i need.