Flow development...

[WPH]

I've driven the actual car and the pull is incredible until the the curve starts to go flat. Engine recorvers from shifts lightning fast but it misses top end power. The gearbox is propably the best part. It's a 5-speed "dog-box" with KAAZ LSD. You can pull gears flat out without engaging clutch and letting of the throttle. When you move the shifter you press a small switch which activates "flat shift"- mode in ECU. Revs are limited to user defined RPM whis is 4700 in our case. Gearshift is very fast but I haven't had a change to check it from ECU datalogging.

Pictures in the beginning of this thread feature the same head opened up at divider to 27mm. Flow is about 10hp higher than in the actual head on the engine. I'm waiting for a new bare head to start with but that will be in the schedule after -09 season. I'll do a complete flow development on my scrap head before. Also have a pair of ARPM's aircooled SuperFlow1 heads (Beetle) to be finished... propably too much at my hands for a moment...

[CraigAPD]

Whats the complete spec of the engine?

The port sounds similar to the Renault 2.0 16v F7R (clio williams) I work alot with.

Ive found that a CSA at the divider of 29mm works very well. This is with 33mm inlets. With this configuration recently we made 249bhp and 210lb.ft torque, with 45mm individual throttle bodies, 11.5mm lift/285* cams, Cr=12.5:1.

[WPH]

85mm bore, 88mm stroke

33mm intake, 29mm exhaust valve
296/12mm@105deg, 304/10.6mm@105deg

46mm ITB's, length 178mm/3rd
41.5mm 4-1 exhaust, 650mm pri, 680mm coll.

compression ratio 12.5-12.7

Your F7R puts out a very healthy torque.How wide is the torque spread?

[CraigAPD]

Its pretty flat between 4800rpm and 6200rpm

It has bore of 84mm and stroke of 93mm. So technically, 2060-odd cc. MAssive stroke though!

The GrpA engines as found in the clio maxi (alla Jean Ragnotti) were 267bhp and 194lb.ft. Pretty much the same base spec as this one I built, but with quite higher duration cams. I guess this is reflected in the different torque figures..