hey guys, just got my dyno done today, very impressed, I have an 88 jimmy with a fully costom built 427 small block. little M block. just dynoed at 405 hp, 450ft.lbs. at the wheels. awsome throttle responce. engine made 707 at fly wheel. just lets you know how much power you lose through drive train. and yes it is supercharged with a vortec blower at 9psi. with methanol injection.

 

Sounds amazing, but 303 HP lost in the drivetrain, that's huge! That's a 42% loss through the drivetrain??? What did you use to determine that your engine produces 707HP?

Just for a comparison, I engine dyno'd my 30 over 350 at 386hp/425ftlbs after I built it. I then chassis dyno'd it with the stock TH350 and 10 bolt rear with 3.08 gears and the results were 304hp/332ftlbs a total ~21% loss through the entire drivetrain. Now the curves didn't look exactly the same due to the presence of the fan, alternator, ps pump, etc... 42% seems just excessive...

 

Yeah that amount of power loss does seem high, but still lotsa power. Any pics of the truck?

 

707 at the flywheel and 405 at the wheels? I think you have some problems there.

 

I agree...that is way too much loss....Are you sure the throttle cable is opening the plate all the way?.....you have to find those missing ponies!

 

OK. did any guy here ever tryed a dyno??? I used to be a auto tech at a place called "extreme automotive" and I used to be a tech for 1/4 drags cars. so If you think that 400 hp at the wheels is not enough, come here and I will get you for a ride, Iam talking about a full size blazer, sideways at 85km/hr. can smoke 33inch tires for a block... and ya, it takes 700 to do that..try arguing with the pros at campbellautomotive.com. they dyno everyday.. check out the website.

 

Did you read any of our posts??? Specifically my first post in this thread? Those are hard numbers.

Congrats on the 400+ mark at the wheels, but 42% drivetrain loss is HUGE, plane and simple. Could you answer my question? How did you come up with the 707HP at the crank? Was the engine dyno'd before being placed into the truck?

Oh yeah, forgot to ask... Do you have any pics of this truck? Engine setup? I'm thinkin' of going with a CSC on my Chevelle. I'm very interested in what you've done.

 

Yes the engine was dynoed first without the chassis. It took alot to make 707 at the crank, first let me start with- dart little M block, 3.814 stroke, 6 inch rods, all eagle 4340. diamond forged pistons, costom roller camshaft, victor jr heads with ported 220cc intake runners, angle plug, monster headers-headman elite series, holley stealth ram intake system, added 9 psi boost, with twin methanol injection. the engine made 550 hp naturally aspired-no boost or methanol. 707 with boost and methanol at crank. the engine builders in edmonton tell me its naturual to loose 30-40% to the wheels on a full size 4 wheel drive. they also tell me its natural to loose 25-30 on a two wheel drive. If you compare gms zz502 killer, this 427 is the same power rating. pics are slim for now because of my tech background, iam a firm beleiver that powertrain first- then body. so here is some of it so far. I also have video of the dyno if your interested but I have to email it to you. As far as 42% loss, it does not feel like it if you were to drive it. 400 to the wheel is enough to scare you, and enough to beat mustangs.!!!

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42% loss does not sound right to me. I've never heard of anyone having that much drivetrain loss. But I'm not a Mecahnic or Engine Builder(just a hobby for me)for a living so I'll let the people that do this a lot mroe than me put there input.

Nice looking truck though.

 

Ona chassis dyno, a 2wd and a 4wd will be fairly close... within 5% of each other... Unless the t-case is causing issues...

Change out all your drivetrain fluids, make sure the tires are at the right PSI...

42% drivetrain loss isn't impossible... just not usual.

With 3.73's you shouldn't hit more than 40% loss...

As an average, you take 15% off of crank power for a FWD car, and 20 - 25% for the average RWD car... The t-case in a 4x4 might bump that up into the 30 - 35% range... The extra meat from the tires + rims might account for that extra percentage... still seems a little off to me as well, but not too far off...

The transfer case and the tires are the major variables throwing off the numbers here...