My Dyno Results

sprintgtvgus · Post by **sprintgtvgus** » Thu Jun 25, 15 4:00 pm

So

Had my 1966 Belvedere with 440 from a 1970 C body on the dyno today.

Mostly it was just to set the AFR correctly and optimise timing.

All done now and it runs a treat.

Spec of the engine is absolutely standard apart from:

Hedman Tubular Headers
Pertronix Igniter 2 and Flameflower coil
Aluminum crank pulley.

It has a four barrel Carter AFB 750cfm carb.

Well, I was interested to see what she would make, tried not to get my hopes up too much as I know that power outputs in the 60's were often way overstated.

I have the graph I can post at some stage, but it achieved 223bhp and 320Lbft of torque.

This made me laugh really, I have just broken 31bhp per litre.

Quite a long way off the 350bhp and 480lbft quotes for a 1970 imperial or 300c.

It drives well and with non assisted drum brakes and standard suspension you could argue it's enough.

Of course, what have other people achieved??

I don't know much about the history of the engine, it seems to be running nicely and not burning oil etc and I was "told" it had had a basic rebuild.

Are there any common faults, eg perhaps the camshafts have worn down etc.

If I get round to it I might do a compression test, but at the moment just happy to be driving her finally!!

Pete · Post by **Pete** » Thu Jun 25, 15 4:45 pm

It is probably a low compression motor with a compatible but soft Camshaft.

As long as you are having fun that is all that matters.

Going fast costs a lot and often spoils the ride on the street....I should know, I have ruined lots of nice cars in the past.

Plenty of advice on here and in the club in general on how to go quick but at the end of the day it is down to your personal objective and wallet.

I have not had a car dyno'd but knowing the weight and having the timing slips and Desktop Dyno gives you a good indication.

Best I have made to date (street car) is 697 bhp from a 400-based 512 Stroker Big Block.

Others in the club have made significantly more..... I think the current record holder is Mopar Mark with his '71 'Cuda and I would think that is around 2500 bhp......

sprintgtvgus · Post by **sprintgtvgus** » Thu Jun 25, 15 5:08 pm

Thanks, I am definitely having fun

According to the codes it should be a high compression engine (but not a "HP"), and as far as I can tell it has a forged crank.

I'm not going for crazy power, that's not really what I bough her for but I've no doubt that I will end up doing something.

I had a 1984 Audi quattro that I spent crazy money on to get to just under 500bhp in a 1300kg car, I feel I have more or less scratched that itch.

I think it's just the fact that I'm burning so much fuel and making so much noise I feel I owe it to the car do do a little better

Blue · Post by **Blue** » Thu Jun 25, 15 5:16 pm

Assume this was a rolling road? If so you have to take a few things into consideration. The factory figures you are quoting were probably a bit on the high side anyway, the factory tended to massage HP figures up or down depending on who they were trying to fool. That would also be engine HP not rear wheel HP which is what you would be seeing. The losses through the drivetrain can be considerable and rolling roads aren't especially accurate with true HP readings.

So be content with the fact that it came out running better than it went in and don't pay too much attention to the actual figures.

Pete · Post by **Pete** » Thu Jun 25, 15 5:16 pm

Well, a winter re-fresh may be on the cards.

Check bearings, pistons and Valve to Piston clearance before selecting a bigger cam.

Pocket port job on the heads, cam chain will be shot (I think they are worn out when they install them).

A good single plane manifold will always wake the motor up.....does not have to cost a fortune....alloy heads are nice but are $$$$'s.....

Jerry Smith · Post by **Jerry Smith** » Thu Jun 25, 15 5:26 pm

I had the 572ci coronet that andyrob has now on the rolling road and it made 592hp at the wheels, the motor was dyno'd when it was built at over 800hp, that's through a 727 so I don't think yours is far off where it should be

Pete · Post by **Pete** » Thu Jun 25, 15 6:15 pm

That's a shedload of loss, Jerry; I can see why people like Powerglides........

Blue · Post by **Blue** » Thu Jun 25, 15 6:29 pm

That's not all loss, there's other things like tyre slippage to consider. Like I said on a rolling road don't pay too much attention to the actual figures, it's a tuning tool after all, you start off with X amount of power and you fettle a bit and find out if you made more or less HP.

Mick · Post by **Mick** » Thu Jun 25, 15 8:32 pm

Even more losses with a high stall converter, mine made 460 on a chassis dyno at 6300 with mufflers and it was still going up, allowing for stuff i've done, open headers and the chip at 6700 i'd say it's around 500 or so.
Those old factory figures are way off. My full weight challenger pulling 113 mph and change is around 420 hp at the flywheel according to wallace which is pretty close to the moroso slide rule.
The track is the true dyno, run it and then put your figures through the wallace calc and you'll get an honest figure but beware you may be dissapointed.

http://www.wallaceracing.com/Calculators.htm

GJUK · Post by **GJUK** » Thu Jun 25, 15 9:10 pm

I understand rollers can be made to read high or low also.

"oh man your engine is Bananarama!..."

"oh look how quick I made it after costing you £1million pounds"

Mick · Post by **Mick** » Thu Jun 25, 15 9:39 pm

Assuming a weight of 3850# it takes 224 rear wheel hp, 250 flywheel HP to run 14.5 at 95 mph, that's got to be close to a lot pre emission muscle car times and speeds.
Mick

Adrian Worman · Post by **Adrian Worman** » Thu Jun 25, 15 9:57 pm

320 ftlb torque at the tyre is pretty good and nothing to complain about.

Listen to Blue & Mick, don't get caught up in all that big number bull5hit, the track is littered with "oh yeah it's making 500/600 hp" cars that can barely run in the 13's, Jap stuff mainly

Mossy68 · Post by **Mossy68** » Thu Jun 25, 15 10:26 pm

Adrian Worman wrote:320 ftlb torque at the tyre is pretty good and nothing to complain about.

Listen to Blue & Mick, don't get caught up in all that big number bull5hit, the track is littered with "oh yeah it's making 500/600 hp" cars that turn out appalling times.

Spot on Ade !

Adrian Worman · Post by **Adrian Worman** » Thu Jun 25, 15 10:36 pm

Yeah you get it don't ya Gaz

I've edited that post now cos it sounded like an attack on our mates who ARE makin big numbers, but these are racers, not street jockeys......

steveo · Post by **steveo** » Thu Jun 25, 15 11:03 pm

Mick wrote:Assuming a weight of 3850# it takes 224 rear wheel hp, 250 flywheel HP to run 14.5 at 95 mph, that's got to be close to a lot pre emission muscle car times and speeds.
Mick

true , think from memory the horse power at the rear wheels for a 69 speck hp 440 four barrel magnum was 220 -240 at the rear wheels , depending on what trans

I believe the hemi was 320 -340