BUILD THREAD 86 GP 2+2~Blown 6.0

motorheadmike

Geezer
Nov 18, 2009
6,817
113
Ottawa, Ontario Canada

81cutlass

Comic Book Super Hero
Thread starter
Feb 16, 2009
3,140
113
Western MN
Cylinder pressure is greatest at peak torque with maximum timing. So it's really easy to break pistons just before and at peak torque because peak torque is where maximum cylinder pressure occurs if yo have timing maximized for HP. The way to cheat this is to get past the peak torque rpm and minimize cylinder pressure around peak torque by dropping the timing 5-8 degrees from optimal. Once you get past that rpm level, then start feeding the timing back in to the peak HP rpm. I want to be clear, this is not the way to make the biggest HP curve throughout the entire operating range, but it is a way to keep the ring lands in tact and the rods in the block. And the idea is that when you're at the strip that you are over the peak torque rpm all of the time. This is why I think 81cutlass should move his rpm window up so as to stay over 5K when he shifts.



OK, I see that Craigslist is like p*rn to you - can't stop once you start (or so I've been told.) But I do believe you need another project or two, I'm sure your wife agrees.

What I am hearing (and slowly coming to the realization myself) is that I need to get some time on a dyno to actually see where my peak torque is. My setup is kinda unique in that not many people run m122 blowers on LS stuff with dyno results, especially not with a 6.0 and a t56 so where the torque peak is kinda an unknown. I can't compare apples to apples, or even oranges. I am trying to compare my apple to a bagel at this point.

Holdener's 4.8 m122 made max torque at 4750
1620133954795.png


And Happel ran a m122 on a 5.3 with torque peak at around 4000

1620134155722.png

1620134176048.png


But all that info isn't necessarily worthless but highly questionable with such different setups. All these combos have 10psi, holdener and happel both have a cam swap too. Holdener has 600 crank, happels is probably 625 crank assuming ~20% drivetrain loss. They both have a stock pulley and I have a smaller one to account for the 6.0 to make 10psi. If I optimize my timing I am probably in the 650 range. I have another 2psi of boost to toss in too. Maybe 675 crank all said and done?

I think I'll keep my plan and try to get it at the track and get it to launch before I find a dyno.

Random ramblings in my head.....






And yes I have a problem with FB/CL, haha. I checked my fleet inventory and with the wagon sale I am dangerously low on Buicks. I really want to do a 8.50's drag week style build with a hatch 73-74 apollo or omega. Logic says I should swap the turbo buick setup in my Cutlass and paint the 2+2 before getting a new project, but impulse says new projects.
 

motorheadmike

Geezer
Nov 18, 2009
6,817
113
Ottawa, Ontario Canada
What I am hearing (and slowly coming to the realization myself) is that I need to get some time on a dyno to actually see where my peak torque is.

Nah, just make a Maths in HPTuners for torque and horsepower and it'll get you in the ballpark. You can the correlate the peak torque number against the cells in your VE table. Fine tune on a dyno if you want.
 

81cutlass

Comic Book Super Hero
Thread starter
Feb 16, 2009
3,140
113
Western MN
Nah, just make a Maths in HPTuners for torque and horsepower and it'll get you in the ballpark. You can the correlate the peak torque number against the cells in your VE table. Fine tune on a dyno if you want.

Using the estimated torque PID?
 

motorheadmike

Geezer
Nov 18, 2009
6,817
113
Ottawa, Ontario Canada
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81cutlass

Comic Book Super Hero
Thread starter
Feb 16, 2009
3,140
113
Western MN
Well this budget build has officially jumped the shark.

I'll be damned yesterday evening I got an email saying the shocks shipped and to expect them tonight. They showed up and I got them bolted in. Besides the factory T bar mount bolts being too short and the holes in the frame needed to be drilled out to fit the supplied 3/8 hardware they fit no nonsense and I had them swapped quickly.

I have been wanting to do some tuning this week but it's been drizzly every evening and it hasn't been condusive. I'm glad these showed up and I got something done.

I had a split second thought today that I might try to make it to the track Saturday since I negotiated my way out of being away from home for the day, but I realized I have a lot to do before I can go to the track with my best foot forward and I don't have the time to put everything together.

I forgot the big NHRA track Brainard which is 2 hours away (actually have never been there, always went to the small closer track in high school and college) has Wednesday night street drags. 5pm to dusk. I might sneak up there next week and see what the suspension work has done since I don't think I'm going to be patient enough to wait until June.

I have to get my tune cleaned up, swap the front shocks to the comp engineering drag shocks I picked up used this winter, pull the front sway bar and put a tool kit together and I should be ready.

IMG_20210505_183308.jpg

IMG_20210505_222640.jpg
 

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