duratec with plenum what max power is possible?

[Hanns Per]

As I am getting older I become more sensible twds. noise from intake and exhaust. I think of using again the plenum of my old CSR 2.3 - 200 installation to reduce intake noise but would like to  stay with 12.5:1 compression and Cosworth 250 hp overlapping cams. 

Will the engine run well with this setup? Has anyone experience with tuning the Duratec with a plenum and what max power can be expected?

thks for Your feedback

Hanns Per

PS: I now have the Duratec 2.0 with SBD Tb's and 260hp but this is very loud.

 

[elie boone]

Do you already have the track day airbox ? that reduces intake noice.

[oilyhands]

In my experience, long duration cams with much overlap dont work very well with plenums, especially in the low to mid range RPM band, however YMMV.

Oily

[Hanns Per]

elie, I thought about this but I would need a shorter manifold to have enough space for the manifold without cutting into the bonnet.

Oily: thks what would be the max duration for a good low and midrange torque, eventually I could go to the 2.5 block  (I have) with 100mm stroke to compensate for less aggressive cams

Thks all

[simon_h]

I don't think you'll get much more than about 240hp from a R500 spec with a plenum. I had a copy of a curve somewhere that showed the drop from 250 odd with the track day airbox on roller barrels. 

[vertew]

I have a CSR 260 with the standard PX600 airbox and a raceco silencer.  I can't add to plenum discssion, but I have fitted sound insulating foil-faced foam to the bonnet. Obviously this needs to be purpose-made for the high temps around the engine bay.  This seems to have made quite a difference to induction noise levels.  Can't really give measurements to confirm (I've got a cheap db meter, but seems fairly hit and miss with accuracy).

tks Andrew.

[Hanns Per]

Andrew tks for feedback, I assume You are on the roller barrels??? Are You?  I presently am on SBD TB's and I doubt it would fit under the bonnet. Anyhow I still have the BR'around and could reinstall them and the Raceco silencer which is also around..

To what extent did You cover the bonnet on the inside? Only the left side where the inlet is? Tks Hanns Per

[vertew]

Hi - Yes, I'm on the standard caterham roller barrels.  

I covered the entire bonnet - see pic.  The foam is ~10mm thick and self adhesive.  As you can also see from the pic, the foam air filter is pressing on the foam slightly and a depression where the expansion bottle cap is too - so the fit is very close.  I got the foam from here, unfortunately it's not listed anymore.

I think the combination of the raceco (freshly packed) + bonnet sound insulation might just be enough to get me through a low noise track day (92db / 102db).  I nearly got away with one last year, but got flagged on last few laps of the day.  So hopefully this would tip tip the balance.

A plenum would no doubt be a lot quieter, but I thought I'd at least have a go with a foam approach.

tks, Andrew.

[OliverSedlacek]

The main problem with plenums is getting them big enough. They should have a volume of at least 7 times the swept volume on the engine, which means 14 liters.

[Hanns Per]

Thank You I did cover the inside of the bonnet with 10mm closed foam and the difference is noticeable, I think this will be good enough, very good. Now I have to get new primaries and secondaries to fit the longer Raceco silencer.