Engine: Rear wheel horsepower (on a dyno) from a stock R1 Avanti??

[brngarage]

Just curious. A friend just had his '63 Avanti R1 with Powershift tested on a chassis dyno. Very good running car, but nothing unusual. Fresh tuneup, etc. Actual rear wheel horsepower was 120. We would like to know if that is about what to expect or is it a little "soft"? Thanks Howard

[j.byrd]

Hmmm, if I remember correctly, around 15 % is considered a normal "loss" on a chassis dyno, and didn't the R 1 have around 240 hp "sort of" advertised ? I know our pure stock 63 Avanti ran 10.2 to 10.6 seconds in the 1/8th mile. No mods at all, and my wife usually driving. Someone can probably figure a theoretical hp number from that.. Your friends sounds a bit low to me, but if it runs good and he's satisfied, then that's enough . Interesting question.

[PackardV8]

Just curious. A friend just had his '63 Avanti R1 with Powershift tested on a chassis dyno. Very good running car, but nothing unusual. Fresh tuneup, etc. Actual rear wheel horsepower was 120. We would like to know if that is about what to expect or is it a little "soft"? Thanks Howard

Yes, that's a bit soft. A fresh, perfectly tuned R1 running on 100 octane will make 240 horsepower on an engine dynomometer. Been there, done that.

That same Avanti, if running an actual, measured 10.25 compression, using typical pump gas, will on a hot day ping like a poltergeist.

Hmmm, if I remember correctly, around 15 % is considered a normal "loss" on a chassis dyno, and didn't the R 1 have around 240 hp "sort of" advertised ? . . . .Your friends sounds a bit low to me, but if it runs good and he's satisfied, then that's enough . Interesting question.

An automatic transmission car on a chassis dyno reading can have as much as 30% loss, which would be 168 rear wheel horsepower.

I know our pure stock 63 Avanti ran 10.2 to 10.6 seconds in the 1/8th mile. No mods at all, and my wife usually driving. Someone can probably figure a theoretical hp number from that..

There are on-line calculators which will estimate horsepower from ETs, but I never trust those to be as accurate. Strip ETs are mostly tires, gears, chassis setup. Just ask Alan about running 6.33 rear gears.

OTOH, the speed at the end of the 1/4-mile especially is an accurate indicator of horsepower. An Avanti R1 weights around 3300#. A 240 real horsepower would be running 14.0 @ 97 MPH. Don't we have some of the better prepared, tuned and driven R1s running in that range?

(As an example of how ET and MPH differ in calculating horsepower, using https://www.calculator.net/engine-ho...&x=29&y=12#tsm If the Stude Tomato weighs 3200# and runs 13.5 @ 111 MPH, using the ET calculator says Ted is making 260 horsepower and the MPH calculator says he's got 340 horsepower.)

jack vines

[bezhawk]

I dynoed an R3 @ 405 hp. so 340 wouldn't seem far fetched.

[Bills R2]

This thread may be of value:
http://forum.studebakerdriversclub.c...ls-Any-experts