Evo 9 retune with Cosworth M2 cams
A customer came in to get some Cosworth M2 cams installed on his Evo 9 and retuned.
In the past, his Evo always seemed a little weak for the mods he had, espically the torque numbers and curve. Wasn’t low enough to sound an alarm but it was on the softer side of 9’s.
So after the install we decided to do a boost leak test since it had never had one. Well, it only took about 3 psi before I knew it was leaking like a faucet. Throttle body shaft seals where toast.
Swapped the seals out out and went to retune it on the dyno.
If it was weak before, it isn’t now.
+28whp / +30wtq peak.
Mods:
TBE / no cat
Denso 720cc injectors
Drop-in Filter
Stock airbox
Cosworth M2 cams
LICP
Walbro fuel pump
GST Boost assembly using ECU controlled boost
GST Custom dyno tune (oem ecu flash)
I’ve seen about every other 9 come through the shop with leaky throttle shaft seals. Not sure what monkeys are putting these together at the factory but it is what it is. I’m beginning to think this is the reason why we see such a spread in power on the 9’s for the same mods.
If I where an Evo 9 owner with a “soft” 9, I would do a boost leak test, you might be surprised what you find
