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littco l450

billbadass

Drag Racing Champion
Location
your moms house
I have to say it depends on what you're doing with the car also, for standing mile or 1/2 mile stuff the difference between how the car behaves on the dyno vs. at the track is huge. I've had tunes in my early days that worked great on dyno and did not work at all and knocked horribly in 15-20 second full low WOT situations. Also these long pulls will really show weakness in fuel systems and other components, like the methanol fuel distribution issues that you see in normal intake manifolds really can be seen in long long pulls as the leanest cylinder continues to gain heat faster than the others, or some motors the coolant doesn't flow as evenly so some cylinders get hotter from that etc. this is not apparent in a 4 second dyno pull or whatever. I bet for road race guys it's probably even more important.

i've always preferred road tuning to dyno for these reasons, but Hoon makes a good point on ethanol and you can also map out the torque vs rpm more precisely if pushing the limits of stock engine stuff

i've always found the best tuners if tuning something really stout will always pull whichever plus is running leanest and manually inspect it, which you can do easier on the dyno too since you can shut it off right there exactly after the pull. so that is one benefit of dyno sometimes too especially if the car is hard to pull the plugs

my guess for 99% of <450whp street cars though it doesn't matter as long as the tuner is good.
 

Ed @ EQT

GOLFMK7 Official Sponsor
Location
Fairfield, CA
Car(s)
MK8 Golf R
FYI, we had a customer reporting similar issues. We just received his turbo and found a severely bent wastegate flap arm. Check out the pictures.

This is most likely to happen when installing or adjust the wastegate actuator by trying to over-tighten the lock nut. Curious if this is the same issue the OP is having.

-- Ed
 

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Amracer1

Ready to race!
Location
Pa
ill check mine when i take it out but i highly doubt thats what happened to mine I was extremely careful with install
 

littco

Ready to race!
Location
London
Show just an update, the turbo arrived back today from the customer.

The turbo is in near immaculate condition, certainly hasn't been run hard.

The wastegate was fully closed, and actuator voltage was at 3.45V so certainly wasn't the wastegate that was causing the issue.

Only thing of note was the DV was damaged and missing part of the surrounding, so much so you can't physically fit it back in the turbo. It was removed when sent back .

The turbo is otherwise not an issue.

So we are down to an installation error keeping the wastegate open , but considering the voltage is correct when closed I doubt this is the issue, the Map was doing something weird or the DV was damaged during installation and not seating properly.
 

Hoon

Autocross Champion
Location
Rhode Island
Had to be the DV, I couldn't see any issues in his map or the logs, plus he tried a standard IS38 stage 2 map and it still didn't spool.

Surprised he couldn't hear the leak.
 
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