Pearls of experience for tuners!

[Barney Paull-Edwards]

Due to friend having spare dyno time,just done few run-ups with different bits on a TDS,results were illuminating.After 270k combustion pressures were within 5% of new,leak down test showed exhaust valve wear,changed for new standard,all other parameters within tolenance.Then came the fun,tried 3 different inlet filters, no difference at all in power, some actually lost.K&N same but will last longer.All sorts of boost controllers tried and none added power AND torque, in fact the best power increase lost 15% torque, tried down road and it was useless below 3500.Having played about all day we then came back next morning and played with temperature,cold air added 14% power over ambient(bucket of liquid co2 in fan), cool day car go better! The biggest real power increase for the real world(including torque) was an old Renault trick,if you inject H2O at higher pressure than boost, then figgures went up dramatically but was very pressure sensitive.Given a Autec/megasquirt set up then power gains of up to 28% including torque are possible,and you coould cheat like Renault and use the washer bottle with a submersible pump in tank! Conclusion,power aint free,and a lot of add ons dont work for power and torque.final figgures for a 2.5 diesel with standard size turbo but 270 degree thrusts and cut-back inlet wheel,4 degree advanced pump were as follows:221hp,361ftlbs,@4750,good enough to bugger guibo on penultimate run!Its bloody expensive trying to improve on a good basic design!!

[skr]

so what pressure was the turbo puting out? stock intercooler?

[Barney Paull-Edwards]

so what pressure was the turbo puting out? stock intercooler?

over absolute,2.1 bar, 1.04 over ambient,the only mod from standard is a cam from an eccentric in Sweden called Jan Carneborn who made cams for me years ago and played about with a bit more lift and a LOT of overlap, seemed to work as regards driveability, his first attempt produced awesome power but was totally undriveable,he also modified the oil feed which seems to work.He wont produce copies but will sell details if anybody has a Prince cam grinder.