Help!
My 2003 MCS Works is way down on power. I've replaced the Bypass valve, the old one was found to not close so I thought I'd fixed the problem but it's still much the same, maybe just a slight improvement.
On the Dyno the power curve goes up to about 120hp then goes flat, I'm thinking the supercharger is the problem.
Any ideas? :confused:

Hi

Sorry to here its down on power
I take it you have check the usual stuff first like air filter, spark plugs, super charger belt if it is in bad condition it will slip and you will loose power
Is it a standard car or you done any mods to it ?

Hi, thanks Marque.
Yes I've checked all the obvious stuff, it's all standard under the bonnet. Engine sounds fine and the car accelerates well around town, only notice a problem on the motorway, sorry, autobahn. It just runs out of puff, no strange noises like slipping belts or anything.
I understand the supercharger rotor tips can wear, not sure how to test this though.

Hi

Thought you might have checked all the stuff I suggested you can get a gauge and sender to check then boost of the supercharger some one like Lohan or gtt would be able to help you. then you can see the pressure the supercharger is putting out
Superchargers normally work or make a really bad noise
Have you tried the disconnect the battery trick to soft reset the DME
Have you got access to a a scan tool for the DME see if there's any fault codes
Have seen something like this when my mates intercooler had a leak might be worth poping off the inter cooler have a good look at the boots and the condition of the cooler see if its ok will have a hunt around see what else I can find
Is it drinking fuel of does it seem ok

Hi Marque,
I was wondering if the lobes / tips of the rotors had worn it wouldn't develop the pressure while not making any bad noise.
Don't have a scan tool, don't even know what a DME is.....
Not found any air leaks but then that would only be noticeable under boost pressure.
Not finding excessive fuel consumption but it is a bit down.

DME is the cars brain controls everything Under the bonnet its just to the left side of the air filter housing
Try disconnecting the battery leave it for for a while then reconnect it min 10 min
Tips could be worn on the sc but I would think it would show up in the mid range as well and under load up a hill if it takes you to the red line cleanly and quickly I would say it's ok there is something else a miss may be throttle body valve is not opening fully to give you full power or you have an air restriction

Just a quick though
when you changed the bypass valve the vacuum pipe the the throttle housing was ok and also the vacum pipe to the bypass valve was it connected from black diaphram housing to the housing to the bypass valve housing short black pipe
On mine i have y peice connected in to the bypass valve for the control in the airbox
Flap do you have this is it connected as if it is not connected it will restrict the air flow and reduce the power

I just had the works airbox fitted at the same time as the replacement bypass valve and all seems fine there, I know the 'Y' piece between the airbox and the bypass valve and am sure it's in place.
But the problem existed before these were fitted and still persists..... So no reduction on the induction side.
Can't be the throttle body as I get very lively performance at average speeds. I will check the 0-60 time, haven't done that since the late 70's......

I think if it is doing to 0 to 60 ok and is nice and lively I think the supercharge may be ok like I say only way to really check the output pressure it is to put a sender and gauge in line to test it it may be worth speaking Lohan or Roland at gt tuning pretty good bunch I only say these as I have had dealing with them found them very helpfull also herd good thing from 1320 mini as well
Will have a think see if I have anymore ideas
Could always do a compression check to make shore that side of thing are ok

I think 1320 is nearer me in London but what about Tony Franks ex JC Garages down in Shorham?