Would something like this be an alternative? I happen to like it...

 

Looks like it may well be. Cheers, Kai.

It looks like my hurdle at the moment is heads. I know Nick is reworking these but by how much I can't remember.

964 heads 41mm intake.
993 heads 43mm intake.
Exhaust ports I believe are the same IIRC.

I'll call Nick tomorrow and discuss...

Here is Jeff's car running his flap slide ITBs with a resonance plenum...

 

Amazing vids - If yours sounds like that Frank, the world will be a better place ;-)

 

I can't wait to see (and hear) your car

 

sounds bad a**.........better warn the neighbours

 

Kai your engine has the 996 plenum !?

awesome videos Frank... car sounds amazing,
seems to be against much faster cars ....

 

UPDATE 6.5

Spoke to Nick...

We're now into our fourth week of head work: The result is 51.5mm intake over 41mm standard and 43mm exhaust. I am over joyed. Nick doesn't like to claim hp figures - but he states 350hp minimum. Have a feeling it'll be v nicely above...

The valves we're using are stainless steel custom Red Tek items.

As for the ITBs - progress is moving along quicker all of a sudden and we're looking into different options.

As a side note, he's getting at least 1 phone call a week through Rennlisters...






Mark, listening to yours as you left last weekend was awesome - the world is already a better place. That rough idle is addictive - to that effect have been listening to you video of the midlands meet.

Cheers me also!

Where's the fun in that - not a chance

Yup believe it is a 996 plenum.

 

993RS heads 46mm intake.
9m heads 41.5mm intake (at entry point).

Since we've seen well over 400hp & 500Nm from the 9m billet heads on repeated dyno tests I would suggest that Nick should resist from making your ports larger as in all probability all he will achieve is a loss of mid range torque.

 

993 RS 46mm heads cost a fortune.
9M heads 41.5mm cost a lot also!
993 varioram heads 43mm seem the most cost effective since they can be bought second hand.

Interesting, could you explain further?

 

Peak torque occurs at (approximately) the same point as peak volumetric efficiency (VE), which is simply another way of saying that at this point in the rpm range the combustion chamber is crammed with air/fuel mixture in a manner that produces the largest bang. To increase the torque at this point you have to increase the amount of mixture in the cylinder. One way of increasing the volume of mixture supplied is to dynamically increase the pressure of the intake air behind the valve just as the valve closes. Intake pressure can be increased by utilising resonant effects from the plenums (hence resonance flaps) or by tuning the intake tract length (ITB & varioram) OR you can increase the velocity of the air flow down the tract and use intake air inertia to pressurise the flow past the closing intake valve. Velocity is proportional to flow area, so larger ports flow the air more slowly....

 

Sounds like there are lots of solutions:

Brilliant thanks Colin.

So can you share more info/ specs on the 9M ITB system?

 

9m make the intake manifolds, linkages and airboxes, in the middle is a Jenvey throttle body, as per photos above with/without airboxes. The port bore profile has been chosen to maximise the airflow velocity through the intake port and they have worked well in all 9m race engine applications. I am not prepared to share the port details for obvious reasons.

The dyno curve shows a comparison between the 9m 3.8 race engine supplied to Singer against a 996 GT3RS engine, both tested under the same conditions on our dyno. Note that the 9m Racing engine has a flatter mid range torque curve.
(Note: the Singer engine was fitted in my 993RS CS for testing purposes)

 

Great stuff - what do you charge for the 9M ITB system without installation, just the full kit?

 

Colin could you please explain why is there a big dip @ 4.7 k on Singer torque curve...!?

thanks

 

The torque dip coincides with the gap in between the 4th & 5th harmonic resonance points of the intake tract. After doing the dyno test I noted with interest that the GT3 had two distinct dips which you could easily feel whilst driving the car.