Rolling Road Results

[erictharg]

End result 136 BHP @6600. Those are Peter Baldwin HP or course, but it feels very strong. I can now see why Adam Wilkinson viewed a limited slip diff as his favourite upgrade! Weber was jetted perfectly. Makes max power with only 24 deg total advance. Also had slight top end misfire that was diagnosed as a plug. Put fresh plugs in and it's gone.
Still having problems starting, despite buying a new battery this morning. Peter's view is that it's the starter. Genuine Lucas reman starter ordered via eBay. Few little tidying jobs to do then it will be interesting to see how the times at Mallory compare with the last race. Peter is also racing at Spa in June so got to find a way to get the Eu. 600 entry for that race.

[sgrant]

136!!!!

That's awesome! You must be seriously pleased with that. How much improvement is that over the previous version of the engine?

You're going to require forced induction to do much better than that i'd guess?

[erictharg]

Very pleased. Last time I was there the engine made 104bhp! There's not much more to be had with the std bottom end and a 7000 rpm limit. A wilder cam would keep making power up to 7500, but then I'm getting close to the limits of the rods, and I'd have less torque in the mid range. So, it's a well balanced set up as it is, and still nice on the road. I think the biggest improvement will now be the driver...
It should mean I've now got competitive power to weight for my class, so hoping to get back in the fight with those Ginettas.

Also got it MoT'd this morning at our local family owned Ford dealer. Checked the lights. Reckoned I'd probably keep it in good shape if I'm racing it, so checked nothing else and sent me off on my own with a Tapley meter to check the brakes! Just asked me to note the readings! Love it.

[Mknight702]

What compression ratio are you running? I think that could be one area that I am losing out on having built the engine initially with forced induction in mind.

[erictharg]

Calculated at 11.5 : 1 static. You need at least 10:1 for a decent nat asp A series (as per original Cooper S). Running a pretty hairy cam (more overlap) means you can get away with more. From memory the chambers are just over 20cc with Omega 6.5cc dish pistons.

[Mknight702]

My fairly rough calculations show I'm running 9.47:1. Head cc'd at 23 so I guess I could stand a thou off the head......

Next time the engine is appart I'll remeasure everything and have a think.

[erictharg]

9.47 is not too shabby. Might not be quite as punchy as you'd like, but shouldn't cause it to be a slug. Now, cam timing would...I know because my engine I timed 10 deg retarded initially just through bad maths!

[Mknight702]

The engine isn't a slug by any means. Its just that the rolling road numbers seem very low in comparison to everyone elses ! I think I only had 83bhp on Pete Baldwin's optimistic rolling road (not sure if this was at the wheels though?) Still, the car runs well, pulls strongly and doesn't have any nasty flat spots so perhaps I should ignore the bhp number....

[erictharg]

As far as I know he only quotes calculated flywheel bhp off the one dial on his brake. In which case 83 is low - given his normally optimistic readings that means it's not so far above stock. Maybe 70 - 75 bhp?
Next time we meet up maybe we can swap cars for a spin to see how they compare?

[sgrant]

Happy for anyone to have a spin in mine for comparative purposes (or just for fun). Mine was measured at 110bhp on Bob Airey's rolling road, but personally I suspect that's somewhere on the optimistic side. 110bhp at the flywheel is about 80bhp at the wheels, so maybe your reading was at the wheels?

stephen