I say no way.....what do you guys think?

I know a guy with a '67 Firebird with a 400 in it. This car is gorgoius, red line tires and all. It's all stock except for maybe a mild cam and some springs. I've heard it running (sounds very stock) and this guy would not risk losing points at a car show for a modified engine. He has almost a 400 point car. Stock intake, stock carb, stock exhaust, you get the picture.........he claims it puts out 405HP at the rear wheels :laugh:

I spent a day at a dyno once and the cars that put out more than 350HP at the rear wheels certainly did not sound stock.......you could almost tell by the thunderous sound if the numbers were gonna be big.

I don't know a lot about this subject b/c I have never built a race motor, but am I ignorant or is he? o No:

ou:

 

stock it had 325hp. at the flywheel.

so he's telling you that with NO headers, oversized valves, head work, oversized carb, forced induction or 'juice' he's going to add almost ~100hp to his rear wheels just by putting a mild cam in it?

not bloody likely. if you assume 10% loss in the drivetrain you're talking about a ~450hp motor.

now, i think a poncho is capable of that performance ... but not without modifications like he's talking about.

if you could there wouldn't be many of us that would be buick fans now would there? or any other make for that matter. why bother?

'yeah mabel, i spent $300 on a 1/4 cam and springs install and increased my horsepower 45%'. :sleep:

actually, i think you should have posted this straight to the 'Best Bullcrap Story' thread. :laugh:

 

Do you have to have a booming exhaust system if you want real power? Could you have a car that sounded like an Electra, and speeds down the track like a 455 Stage 1?

 

I should have made myself a little clearer.......even with a super quiet exhaust, you can hear the loping of a powerful motor when it idles. You can also see it shake. I don't think a 400 CI could make that kind of power and still have a quiet smooth idle. :bglasses:

 

Keep in mind that these are 325 gross HP, nowadays that's somewhere around 215 SAE HP.

 

I'd bet he probably putting around 225-250 HP to the rear wheels at most.

 

IMO thats not possible with a stock motor.

 

OK with that said, here's a question to all that have posted dyno results for their engines on this board. Are your numbers SAE or Gross?

 

depends on whether the member took his readings on an engine or chassis dyno.

most guys on an engine dyno will have their accesories installed (unlike the manufacturers) when testing the motor so you'd just be looking at driveline losses but you still need to pay attention to their details.

 

450 To the wheels with the stock 400ci/cam? Bs.

 

Only older car I know that has 450 HP from the factory stock is the LS6 454 SS chevelle. I don't know what that was rated in (gross or sae) but either way that is how it was rated at the factory.

 

That had to be gross HP.........the torque was up there too :Brow:

 

So, there isn't an actual numerical conversion from bhp to sae net? I wonder what my 1976 455 would make with no trans, or accessories.

 

Bad Boattail, so now they now rate HP as SAE.

Wow so these new computer engines that are putting out 325 HP must be blowing the doors off our old muscle cars?

What am I missing here?

 

Somewhere in the 1971 literature, it mentions how much drag all of the options put on the HP ratings. I forget if it's the owners manual, the big "bible" or where, but it does state a 55 hp loss, which would be about right. The only thing that the older Muscle cars have, especially the Buick, is all of the torque comes from the low end. As opposed to making peak Hp around 8000 rpm.

 

Of course then again, if the HP is less in Gross than SAE, wouldn't the torque rating go down too or would it remain? I had to rethink that one... o No: Thanks

 

cody
hp IS torque ... at a given rpm. the actual formula is:

hp = tq * rpm / 5252: note that at 5252rpm hp = tq ( 5252 / 5252 = 1 )

so there are hp AND tq losses in the driveline ... or perhaps more properly stated, there are hp losses in the driveline BECAUSE OF tq being lost due to inertia and friction.

if the HP is less in Gross than SAE
backwards. the gross (flywheel) # will always be higher.

 

Ok, thankyou for clearing that up. :beer :TU:

 

405, no. I got a highly modified 350 in my truck that don't even get that.

 

bs

Male bovine waste, pure and simple. The guy is wishing that his car put out 405 hp. I built engines that would, and they shake the ground, buildings, windows, mess up the neighbors tv , ect. when they were running. :Brow: