Bob, any update on a CMI sport tube dyno test?

Thx

I've not done any stock 502's. I ran a stock 7.4 - 300 HP on the propshaft dyno. It made 307.

Pantera is checking on a set to test. I will probably have that engine back on the dyno next week, so I'll test whatever I have at that point. The customer wants his boat back!

Quote:
Originally Posted by cobra marty
What was the Torque loss thru the bravo drive? is that constant with rpm? Do you have any curves showing HP and TQ with stock and with Dana exhaust?

Torque loss as a percentage at any rpm will be the same as the horsepower loss, since they are related 1:1.

Michael

Only at 5252 rpm is TQ=HP and 1:1 relationship. When I lookid and the numbers and calculated the difference between crankshaft and propshaft HP and TQ I found that between 3500 and 4000rpm was an area of high loss for both HP and TQ but for further rpm there seemed to be about 43-45TQ loss at all rpm regardless of TQ amount and the HP loss increased with rpm and increase HP. What this means to me is that TQ is a constant loss regardless of rpm or amount and HP loss will increase with rpm which is just what will happen to HP in the HP=TQxrpm/5252 formula.

I would love to see the propshaft test repeated with the Dana's and synthetic lube-Amsoil or redline.

Great post. Thanks.

Great stuff. I have always wondered about gains from removeing the turbulators. It's nice to have the facts.

What about testing a set of resonators?. As far as I know, Mercruiser is still insisting that they be used whenever possible to help reduce exhaust "tuning". If you read the installation sheet that comes with them it says that they do not reduce power, and it some cases actually make power. I've always wondered about this.

Dave

Sorry guys it's boating season in Texas !!

Now, if someone wanted to supply me with a substitute motor while Bobl continued testing my 496.....

Yep, I already have 15 hours on the new baby ZR. The partying has officially begun

PS: Mark, Thanks for being the guinea pig on this deal.

more torque = more friction
so more loss with more torque makes sense to me, after all the oil gets hotter at the same rpm doesn't it...

Very informative and well done. Thanks for sharing.

Any CMI's promised or available yet for test?