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Re: Boost Cut Off - Resolved (maybe)(long) Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 16 Aug 2006 08:02:02
In Reply to: Boost Cut Off - Resolved (maybe)(long), TheAck, Tue, 15 Aug 2006 16:20:43 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Hitting boost cut-off doesn't do any damage to the engine- that's the control system protecting the engine. It's getting to cut-off that is the issue.
So - is running higher boost than stock damaging your engine - I can give you an emphatic maybe. Yes. Kind of. More boost is more heat and stress. So theoretically, any extra stress will reduce drivetrain life. How much? Darn fine question.
Many folks out there are running over stock boost successfully. Of course, the folks that grenaded their engines aren't running, almost by definition. I'll say this-
Running higher than stock boost is probably OK IF:
The engine is in good shape - good compression, etc.
The engine is tuned up - good fresh plugs properly gapped, DI in good shape, fresh clean filters (air and fuel) All hoses OK.
Frequent oil changes, and running synthetic is a REAL good idea.
The cooling system is in good shape - radiator has good flow, coolant flushed at regular intervals.
The drivetrain is OK - tranny strong and not generating any bad sounds, CV joints in good shape, all engine mounts in good shape.
You don't nail it all the time - watch dumping too much heat into the cooling system. Avoid (limit?) full boost in low gears - all that torque multiplication is fun, but it stresses the tranny.
If you plan on making a habit of it, I'd go over onto the Performance board and see about fuel system upgrades. You may be taxing the fuel flow at really high boost, and if you don't have the fuel flow, the engine will start to run lean and detonation will follow. Detonation at high boost can blow a hole in a piston very quickly.
I wouldn't do it if:
You have an automatic tranny. There are folks that are running higher-than-stock boost with slushboxes. However, the ZF is a weak spot in the 9000, and I think it is playing with fire. Saab limits engine power in the automatic cars, and I suspect they have a good reason.
I wouldn't run higher boost if you have the opposite of any of the above items - a tired engine or weak tranny; marginal cooling system, old and tired filters. If a car is a little beat, running it hard is a very sure way to kill it. If you just want to have some fun with the car as you drive it into the ground - go for it - it's yours. If you're looking for longevity and power both, the car had better be in good shape to begin with, and to make sure you stay on top of all maintenance.
posted by 192.249....
, Wed, 16 Aug 2006 08:02:02 <-- Viewing This Message
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