3.2 on PMO carbs: freest flowing air filters?

[911hillclimber]

I have well oiled K&N filters on my hillclimb flat 6 3.2 engine, and I'm interested to collect any views and experiences about other filters, ie ITG.
Anyone with any thoughts please?

[KS]

I'm tempted say 'none'...

[911hillclimber]

The risk of swallowing kitty litter at many venues I do is too high, also the junks all over the car when towing.
I think ITG are a good bet as they do a 911 special, but there may be others.

[BILLY BEAN]

I have ITGs on a 2.7 with high butterflies. The filters do not have any covers over them to restrict air flow. I have rain shields on the engine lid grill. I purchased thr ITG system from Tech9 who provides a simple flat housing for them to sit on which has large grommets to hold the assembly onto the injection tracts. Darren65 I think has the same kit on his Mongrel. Phil, who owns Tech9 uses the same set up on his personal car. He says that the power loss using his ITG set up is around 6bhp. No data to back that up.

[KS]

That ITG setup was prototyped on my 74 Carrera, the first such setup they’d done.

[911hillclimber]

6 bhp is a poor return in some ways?

[neilbardsley]

I know you will not consider it but turn off the fan for the run!!

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[Gary71]

Aircon clutch connected to a micro switch under the throttle pedal. Full throttle = fan off.

[911hillclimber]

If that was a good idea it would have been done before?

In a 40 second run this engine will rise a good 15 deg C on it's own let alone being forced into a higher temp or a more rapid rise.
I think I'll go slower and enjoy the reliability!

[neilbardsley]

Don't all formula Vees run without a fan?

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[KS]

Don't all formula Vees run without a fan?

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A 1300cc four cylinder engine generates a lot less heat through friction than a six cylinder engine of more than twice the size.

[BILLY BEAN]

6 bhp is a poor return in some ways?

Maybe if what I was told was correct. Compared with loss of 11bhp from other systems using mesh and paper filters.

[911hillclimber]

Difficult to work out, everyone who makes these things claim improvements.
Might get a better bang for the buck from bigger choke diameters.

[BILLY BEAN]

Difficult to work out, everyone who makes these things claim improvements.
Might get a better bang for the buck from bigger choke diameters.

Agree Graham. I did not have the ITGs when the engine was on the dyno rig so could not make a comparative test.

[911hillclimber]

After a lot of conversations with cleaver people this last weekend on this subject, plan is to make some 40.5mm chokes and take the car so equipped to the RR and see what happens at the end of the season.