Hi,
Question mainly for the builders/tuners. Had a good day @ G-Force on Saturday but the graph showed something odd with boost on the 2nd turbo (see attached graph)...
Everything\'s going fine, transition happens as normal and boost returns to ~0.72 bar around 4700 RPM. It then drops off to about 0.6 bar falling to 0.5 at a little over 7k rpm.
At the moment the car\'s just got Cat-back and a street-ported rebuild. No ECU or anything else.
Suggestions yesterday were that it could be that the cat is restricting the exhaust but I\'m not sure this would reduce boost - I suppose as being too free-flowing would cause a spike, not flowing enough may cause the opposite.
I\'m getting hold of an Apexi next week and will be going de-cat and downpipe + mapping in May, hopefully this will sort it out.
Iain
Forgot to add - if the boost had remained ~0.75 how much higher (as a gueestimate) would peak power have been?
Iain
If the cat is blocked or there is an exhaust restriction, the usual sign is that power levels off low down the rev range and your mixture just gets richer and richer.
I\'m not too knowledgable about the stock ecu, and how it controls the boost, could be that the porting is throwing the boost off. One sure way to see would be to borrow someones Apexi ECU and try that. If that cures it then you\'ve found the solution at no cost :)
I reckon you would have got about another 25 bhp if boost had not dropped.
Regards
Max