boost settles then climbs again until overboost kicks in??????
28 July 2002, 07:11 PM
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Out in a freinds cossie (F plate 2wd) highly modded.
he's complaining of overboost and saying the spring in the actuator is not strong enough.
ok fair comment I thought BUT on watching the boost guage (3rd gear WOT) the boost rose to around 17psi and settled to just under the 15 marker, not very high boost I thought, then it starts rising again 20....25...pop, bang, dam I wasn't watching says the owner ( he usually takes his foot off when it gets to 20).
Never seen this before (ie boost settling and then rising again).
He assures me he was WOT all the time.
What the **** is up with that thing.
He's a little reluctant to go back to the rolling road where he had some work done as he went in for a 100 pound tune and came out with a 3000 (yes thats thousand) pound bill (the cams were fcuked, I'll vouch (sp?) that he wasn't done over as the cam bearing were whining like a stuck pig )
he's complaining of overboost and saying the spring in the actuator is not strong enough.
ok fair comment I thought BUT on watching the boost guage (3rd gear WOT) the boost rose to around 17psi and settled to just under the 15 marker, not very high boost I thought, then it starts rising again 20....25...pop, bang, dam I wasn't watching says the owner ( he usually takes his foot off when it gets to 20).
Never seen this before (ie boost settling and then rising again).
He assures me he was WOT all the time.
What the **** is up with that thing.
He's a little reluctant to go back to the rolling road where he had some work done as he went in for a 100 pound tune and came out with a 3000 (yes thats thousand) pound bill (the cams were fcuked, I'll vouch (sp?) that he wasn't done over as the cam bearing were whining like a stuck pig )
28 July 2002, 07:46 PM
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May be the actuator, might be that one of the hoses that goes to the actuator has a small hole in it, this would possibly not show until constant positive pressure is forcing the hole open thus acting like a bleed and raising boost.
Bets way to check IMHO is to remove any boost controllers and run a pipe directly from the turbo to the actuator, iirc.. cosworths are fitted with a -31 actuator which should be set at 1 bar unless adjusted... so.. doing the above should give a constant 1 bar (14psi) if not its bout £85 for a new -31, or £1.50 for a new pipe
Rob
Bets way to check IMHO is to remove any boost controllers and run a pipe directly from the turbo to the actuator, iirc.. cosworths are fitted with a -31 actuator which should be set at 1 bar unless adjusted... so.. doing the above should give a constant 1 bar (14psi) if not its bout £85 for a new -31, or £1.50 for a new pipe
Rob
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