77mm pulley safe???
currently I have and MK113 with the following mods:
83mm pulley
race IQ tune
Long tube headers
High flow cats
rear Resonator delete
PLM XL heat exchanger
Upgraded 001 heat exchanger pump
Everything else is stock. I'm getting a new tune cause the current one feels too rich and lacks power down low, really not happy with it. So im considering a smaller pulley for more boost, and was wondering should I go with a 76/77 MM pulley and if it's safe for our motors, and what type of gains could I expect.
Car is used as a highway rocket not drag raced with back to back pulls.
So...77mm pulley or should I invest in the crank pulley and get the extra boost from there? If so what size crank pulley and belt combo?
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Best of luck
EDIT:
PS Personally, I'd never touch the crank pulley, but that's just me. I know plenty of folks have run bigger cranks (a lot of those same folks are stacked, too) with thousands of headache-free miles. No matter what you do, I'd recommend the UDP pulley kit and belt wrap kit - helps with slippage and holds full boost all the way with aftermarket pulleys (even stock pulleys).
Last edited by ArmoE55; Nov 20, 2023 at 12:21 PM.




All the mods on mine:
72mm clutched pulley
Belt wrap kit
010 pump
split cooling system with larger front mounted intercooler
kleemann mid length headers, all cats removed
"custom dyno" ECU tune after all mods were installed
as for measured power figures my car is an anomaly. The shop did it for the previous owner. The shop is "Solo Motorsports" in Atlanta. They measured only a minimal increase in HP and torque at the rear wheels. When all was said and done, if you assume 20% drivetrain loss my car was making stock power with all the mods. It was on a Mustang dyno, which is known for breaking hearts.
But the butt-dyno in the real world says it's making far more.
All the mods on mine:
72mm clutched pulley
Belt wrap kit
010 pump
split cooling system with larger front mounted intercooler
kleemann mid length headers, all cats removed
"custom dyno" ECU tune after all mods were installed
as for measured power figures my car is an anomaly. The shop did it for the previous owner. The shop is "Solo Motorsports" in Atlanta. They measured only a minimal increase in HP and torque at the rear wheels. When all was said and done, if you assume 20% drivetrain loss my car was making stock power with all the mods. It was on a Mustang dyno, which is known for breaking hearts.
But the butt-dyno in the real world says it's making far more.
All the mods on mine:
72mm clutched pulley
Belt wrap kit
010 pump
split cooling system with larger front mounted intercooler
kleemann mid length headers, all cats removed
"custom dyno" ECU tune after all mods were installed
as for measured power figures my car is an anomaly. The shop did it for the previous owner. The shop is "Solo Motorsports" in Atlanta. They measured only a minimal increase in HP and torque at the rear wheels. When all was said and done, if you assume 20% drivetrain loss my car was making stock power with all the mods. It was on a Mustang dyno, which is known for breaking hearts.
But the butt-dyno in the real world says it's making far more.







