1966 ford 427 le mans race engine simulation dyno numbers

[vector1]

Originally Posted by elmariachi

If you'd be so inclined, here is my Comp 294S, installed with 5* advance:

Adv Duration 294 int./294 exh.
@ 050 inch Lift 248 int./248 exh.
Lash 0.022 in.
.605 lift
Lobe center angle 110
Lobe separation 106

using 10.5-1 compression, with the cam straight up.

512 tq @ 5000/529 hp @ 6000, avg tq 444, avg hp 368

cam optimized for max avg. hp at 3 deg advance

511 tq @ 5000/521 hp @ 6000, avg tq 449, avg hp 369

both above with 8" idle vacuum

[elmariachi]

I am at 9.8:1. Thanks.

[vector1]

from open exhaust to 3" inlet dual race muffler that flows 2000cfm total

512tq/510hp to 506tq/506hp

from open exhaust to 2" inlet dual race muffler that flows 900 cfm total

512tq/510hp to 463tq/462hp

from open exhaust to 1.5" inlet dual race muffler that flows 500 cfm total

512tq/510hp to 436tq/422hp

this i find very interesting.

[vector1]

Originally Posted by elmariachi

I am at 9.8:1. Thanks.

no problem, i just wagged the compression.

[patrickt]

Originally Posted by vector1

this i find very interesting.

A couple of years ago we had a nice thread on "Dyno Games" and tricks that can be used when putting an engine, or car, on a dyno to get higher numbers. We also had a discussion, and at least one of the better known engine builders participated, on the validity of advertised HP numbers. In response to my question on why the engine dynos are done with open headers (when nobody around here runs open headers and the exhaust sucks a huge amount of power off) he truthfully answered "because everybody else dynos that way and if I put an exhaust on there my engines won't appear competitive" -- or something like that. IMO, a "truthful dyno" run is done with the exhaust bolted on and the water pump pumping.

[lovehamr]

Patrick, the question then becomes; Who's water pump? or What exhaust system? Is there a standard? Seems to me that this would open a big ol' can o' worms for no real reason.

Steve

[patrickt]

Originally Posted by lovehamr

Patrick, the question then becomes; Who's water pump? or What exhaust system? Is there a standard? Seems to me that this would open a big ol' can o' worms for no real reason.

Steve

That's a valid point. BUT, having studied the posts on this forum for over a half dozen years, I would venture to say that more purchasers of engines believe their dyno sheet numbers than understand that those are not the numbers that are really powering their cars. You understand that, I understand that, but most people on this forum don't. Frankly, I would be happy if engine builders just had a black box warning down at the bottom of their dyno sheets that said "this dyno was done with open headers and blah blah blah, you can expect up to a ___% power loss or more when these items are attached to your engine."

[patrickt]

Technobabble: How to Lie with a Dyno
http://www.modified.com/editors/tech...ble/index.html

Turbo Performance: Dyno Tricks To Be Aware Of
http://www.turbomagazine.com/tech/04...ems/index.html

Hot Rod: Dynos Don't Lie, But The People Who Run Them Can Cheat
http://www.popularhotrodding.com/fea...ing/index.html

[Anthony]

Originally Posted by Gunner

Needs mufflers, air cleaner, water pump and alternator to be an apples-to-apples sim. Fan, too, for 60s tech. (When did electric fans become common?)

Actually, earlier in the '60's, the engines were tested without alternator, mufflers, etc., to get the most HP from the engine, as it was an advertising thing to sell more cars, advertise your car with the most HP. Often, the HP was overrated, like in my 1965 442, which was rated 345 HP, and more likely about 300 hp or so. In the late '60's, some engines were intentionally underrated for various reasons, the L88 vette, @ 430 HP (actual 550 HP) so more average people would buy the less expensive 427-435 HP for less money. The 428 CJ was rated 335 HP (more like 400-425 HP), less than the 428 PI (360 HP) , maybe for insurance, maybe for drag racing class assignment. The 426 hemi was rated 425 HP despite changes over the 6 years of passenger car production.