Post #43
As long as Brett isn't believing what Longmans dyno used to read you'll be ok. My '270bhp' made 240, and ended up been mapped to 235 for driveability reasons. I had 2 engines 'rebuilt'by Longmans whilst Brett worked there and both failed, one on its 5th lap, next one after 1 track day.
The only btcc stuff that isn't great is the cams, they were designed to meet regs and have very very severe opening and closing ramps with masses of full lift duration. not great for anything other than max power to meet regs. Any major cam manufacturer can make off the shelf cams that will be better in almost every way.
BTCC heads are good, check the valve seats though.
Cranks and rods are generally good but get them crack tested and new bolts.
Pistons are generally good dependant on inspection.
I personally would replace valve springs unless they are guaranteed new as one dodgy valve spring will f**k an engine in no time, valves also, for the sake of £300 it isn't worth the risk.
You have to remember the btcc stuff is knocking on for 15 years old now if it is original stuff and whilst it might not have been used for a long time it doesn't mean it hasn't had a hard life so inspect everything and if you aren't happy replace them. Arrow rods have inspected the 2 sets of rods I have and have passed them both so I'm happy with that and well worth the £99/set it cost me.
NA power is useful for few reasons, race series regs been the main one. It used to be NA was nice linear power delivery but Rich_W's SC are pretty much as linear.
If I was building a track day car I would be building a medium boost SC engine, aiming for somewhere around the 300bhp mark (for tire and gearbox longevity reasons) and <1000kg. The only thing I had issues with Rich_W's SC setup was the height of the supercharger which I felt weighed too much to be high up in the engine bay but thats just me been really anal, and maybe the boost pipe routing which has been addressed by a few people. Other than that I couldn't fault it at all.
As always though, power means little without adequate braking and suspension/handling. I remember having a guy come up to me at a trackday with a Nissan GTR R34 with somewhere north of 400bhp asking what I had done to my car because he couldn't catch me, same at the Nurburgring with an Impreza owner with similar power, the answer in both cases boiled down to some AP racing brakes, a Quaife diff and some KW V2's, engine was standard bar a filter, de-cat and exhaust and a kerbweight of around a ton. Set it up right and drive it right and power will be the least of your worries....
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Oulton Park in a BTCC 306 vid 1
Oulton Park in a BTCC 306 vid 2
Lap of the 'ring