Lumpy cams on a turbo engine?

[ELiTeHaYDeN]

How do lumpy cams effect a turbo'd engine at standard boost pressures etc.

Due to overlap the boost would get blown out the exhuast? at low rpm atleast..?

funny thing is it still boosts really early

[pidge]

A Really Bad Idead

Some un-combusted Air/Fuel mix gets blown straight through, and the engine ends up with burnt exhuast valves.

Don't forget that with a Turbo charged engine, you're cheating and forcing air/fuel mixture into the cylinders, instead of trying to optimise the air/fuel mixt flow into the cylinder with the right cams, long intake runners, tuned Exhuast runners etc.

[Bazda]

but lumpy cams give u the big hp.
tuned right with a proper ecu will be awesome

[ELiTeHaYDeN]

well just so you know its had lumpy cams(reground) for the last 4 years, and compressions are only like 5psi down from factory spec. aka no burnt exhuast valves, however im changing valve seals etc and while its all apart i was thinking perhaps standard cams would yeild better response around town.

however i have no idea how 'lumpy' they are, all i can say is stock idle is 600rpm, and it gets very unhappy at anything less than 1000rpm, its been suggested they are around 250-300lift. power seems to really come on hard at 4000rpm.

just after some ideas/opionions,

[Drifter4ag]

of course standard cams are better for around town but .. all the big power engines in japan run fairly large duration and lift camshafts .. like supra running 288 in / ex shite like that pushing 700ps daily drive

[Tranquil]

Look at the dur/lift of Group A spec rally cams. More orientated towards torque thus a little more streetable.

[Gadget]

Pidge has the right idea, but the 'damage' isn't limited to the exhaust valves. From what I've heard, indeed duration causes the pressurised air straight thru the combustion process and it will quite often combust in the turbo(s), thus shortening the life of the turbo(s).

Lift on the other hand, lift is good. So long as you can get 'em shut But of course lift doesn't give you that luffly lumpy idle

[Dell'Orto]

..and it will quite often combust in the turbo(s), thus shortening the life of the turbo(s).

Antilag in a nutshell

But yes, big duration isn't good for turbo motors, its the lift where you make massive gains

[suberimakuri]

and your car might not idle at 600rpm due to stock ecu not set up for that sort of engine characteristic.