[Z OH 6]

Originally Posted by Blackdevil77

Motor Trend got 127.5 mph trap speeds and motorweek got 128 mph. A few owners hit 128 mph as well. According to the list on here, most ZL1s trap around 123-125, with some exceptions hitting upper 120s.

I have yet to see a real world BW trap 127-128 other than the one that had a ported blower which according to your logic should have put it around 132+mph in the 1/4 and that didn't happen. GM is not underrating them, they make slightly more HP than the ZL1 but weigh slightly more so its not much difference at all, certainly not a 50whp difference which would mean that the BW makes around 710hp at the crank. I'm not buying that because there's no data to support it.

[Blackdevil77]

Originally Posted by Z OH 6

I have yet to see a real world BW trap 127-128 other than the one that had a ported blower which according to your logic should have put it around 132+mph in the 1/4 and that didn't happen. GM is not underrating them, they make slightly more HP than the ZL1 but weigh slightly more so its not much difference at all, certainly not a 50whp difference which would mean that the BW makes around 710hp at the crank. I'm not buying that because there's no data to support it.

I listed several dyno graphs of owners, most of which are around the 600 rwhp mark while some are over that. I know dynos vary, and conditions play a roll, which is why I’m looking at multiple graphs.

Maybe if it’s possible someone can do back to back pulls with both cars stock, same day same dyno and get a more accurate idea of the difference.

Did they ever say what was changed in the BW LT4? I know they made some revisions, they just never specified what. If they did, I missed it.

[Z OH 6]

Originally Posted by Blackdevil77

I listed several dyno graphs of owners, most of which are around the 600 rwhp mark while some are over that. I know dynos vary, and conditions play a roll, which is why I’m looking at multiple graphs.

Maybe if it’s possible someone can do back to back pulls with both cars stock, same day same dyno and get a more accurate idea of the difference.

Did they ever say what was changed in the BW LT4? I know they made some revisions, they just never specified what. If they did, I missed it.

My ZL1 dyno'd 597whp stock with a Rotofab intake. You're right dyno's vary which is why its a tuning tool. I believe it was stated that the intake was slightly different, larger TB, and different tuning.

[Blackdevil77]

Originally Posted by Z OH 6

My ZL1 dyno'd 597whp stock with a Rotofab intake. You're right dyno's vary which is why its a tuning tool. I believe it was stated that the intake was slightly different, larger TB, and different tuning.

That’s stout. Big gulp or standard? Did they specify a size?

I’m surprised no shop that had their hands on one didn’t take a deeper look at what was changed.

[Z OH 6]

Originally Posted by Blackdevil77

That’s stout. Big gulp or standard? Did they specify a size?

I’m surprised no shop that had their hands on one didn’t take a deeper look at what was changed.

Standard Rotofab. GM just doesn't underrate their cars from my experience. If they state that the car makes 668hp, that's what it makes, give or take a few HP, same as any car.

[Blackdevil77]

Originally Posted by Z OH 6

Standard Rotofab. GM just doesn't underrate their cars from my experience. If they state that the car makes 668hp, that's what it makes, give or take a few HP, same as any car.

That’s my thoughts to, until this one. After seeing several people post stock numbers over 600 rwhp while the average for our cars is in the 550 range, it’s making me think they’re making more. Lowest dyno I’ve seen so far for a BW is in the 58X range. Unless they all were on happy dynos.

[arpad_m]

600 rwhp is a much more desirable output than, say, 585 or 590, dyno operators may play with correction factors just to make owners happier. Then again, it'd be nice to see an actual Blackwing tune, that would answer most questions.

[Blackdevil77]

Originally Posted by arpad_m

600 rwhp is a much more desirable output than, say, 585 or 590, dyno operators may play with correction factors just to make owners happier. Then again, it'd be nice to see an actual Blackwing tune, that would answer most questions.

That’s possible but multiple times from multiple shops?

I’d like to see back to back pulls, same dyno, same day and time, two stock cars with the same transmission. Only true way to tell.

[SpeedLimit]

Boost in the video is 11psi ??? My guess would be better flowing exhaust manifolds and tuning.

[Blackdevil77]

Originally Posted by SpeedLimit

Boost in the video is 11psi ??? My guess would be better flowing exhaust manifolds and tuning.

Might be. I'm curious why/how the power keeps climbing to redline instead of plateau-ing. Did they make any changes to the cylinder heads?

[Blackdevil77]

I don't think any M6 ZL1's hit 128 mph stock. And these things just came out, this is only the beginning. And they're heavier. That's why I'm saying they must make more than an additional 18 horsepower.

[Gunkk]

Upgrades!

[arpad_m]

Originally Posted by Blackdevil77

I don't think any M6 ZL1's hit 128 mph stock. And these things just came out, this is only the beginning. And they're heavier. That's why I'm saying they must make more than an additional 18 horsepower.

The new tune on the new architecture is probably more aggressive across the rpm range, it isn't necessarily the peak horsepower number that's much higher.

[Blackdevil77]

Originally Posted by arpad_m

The new tune on the new architecture is probably more aggressive across the rpm range, it isn't necessarily the peak horsepower number that's much higher.

Exactly, I posted a picture of a dynograph from a BW. The torque curve looks much flatter across the rpm range.