Discussion Forum - Northstar Chevelle Club

Hope it goes well for both cars, looking forward to seeing the results!

So I'm now trying to figure out how much money to throw at the Chevelle again.

Online calculator shows:
3700lb Chevelle w/driver going 115 trap speed is making 439hp at the wheels
4150lb G8 w/driver going 109 trap speed is making 419hp at the wheels

Those numbers might be a little inflated due to tailwind, but they're not too far off. The most shocking part is that she's within 20rwhp of me with stock exhaust manifolds, cats, full factory exhaust (except the tailpipes), 5 mufflers, stock intake, 20 less cubic inches, and through an automatic!?!?  The G8 has better heads, bigger bore, and shorter stroke. Both cars have the exact same cam.

I probably should be happy with 439hp at the wheels from 383 cubic inches... but I'm not. 

Watching the vid, you are shifting rather slowly and carefully, to not miss a gear. I believe, if you were speed shifting, the et would have been lower and the calculator may have come up with a higher hp estimate. The trap speed seems low for the et too. My best time with my old '70 SS was 12.65 with a 118 trap speed with 3.73 gears. My gear ratio may account for the higher speed with a slower et and that was in 3rd gear. No room to pick up forth. Maybe you could have grabbed 1 more gear and raised the trap speed ? The calculator only takes into account the numbers and not all the variables. Running almost a full second faster than the G8 one would certainly expect your engine to be producing a fair amount more hp... and Jenna had the advantage of the automatic "speed" shifting for her. Get the Chevelle on a chassis dyno next year and you may have a different outcome and possibly, a more accurate estimate of rwhp What is really hard to believe is the et for the G8. I remember the days when a 13 second street car cost a LOT of money to modify and the G8 damn near went into the high 12's. Over 400 rear wheel hp on a street sedan ?? Obviously, 50 years of engine technology has drastically changed the game.

I was wondering if the hydraulic clutch was slowing down the shifting. Have you ever tried just lifting and dropping your right foot while yanking the lever without the clutch ? It's cool when it works, but is a bit hard on the engine when it doesn't. With your rev limiter, it would prevent over revving, where my LS 5/6 engines sometimes bent push rods for me to change in the pit. I always carried extras, even on the street for missed shifts. Rocker arms too, as a few times, the 7,500 rpm drove the push rods right thru the stock arm...

That will be cool if it gets better with the shim. My rollback has a hydraulic slave to fork set up and needed replacement. There is NO bleeder on the slave. All the air needs to work it's way up the hose to the reservoir on the firewall ?? What the heck ? I bled it some by leaving the hose loose, but it still took a while for it to work properly and I could stop topping off the fluid.

That's cheating Keith! 

Looks like fun.  

Lost in the 60s wrote:

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What is that ?? some kind of ratchet shifter that cuts the ignition when you yank it ?

Anyone else have the subject title disappear on a reply page ? It keep getting the message that the title is too short and all that is in that line is "RE" ??? I have to type in the thread name.

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 Dog gears shifted sequentially.  There is a strain gauge in the shifter linkage that sends an ignition cut signal to the computer.  The ignition cut takes the load off the dogs enough to disengage them and shift into the next gear.