Can some one tell me where to find performance curves (hp,torque) on a stock 225 (marine if possible)

Thanks

if you or someone can get me the cfm of the carb, and the stats on the cam, i can give post a graph of what the estimate should be

Thank you

is this enough info?

Carter 2 Bbl. Carb. PN 3462779 (1.44 throttle bore)

Marine engine camshaft #E7885M . It is a 244-degree duration with .405" lift and 26-degree overlap.

All i need now is how much cfm that carberator puts out. anyone?

280cfm@3" has been reported.

Cecil

This is what dyno2000 estimates it to be with all the stock items in.

thank you very much.

What is Dyno2000?

I would highly suspect that curve. A stock Slant, even w/2bbl, peaks in HP at around 4000-4200, and drops fast after that. I have seen dyno curves with a broader torque curve too.

Lou

_________________
Home of Slant6-powered fun machines since 1988

FYI, the cam used in slants from '71 (or '70, can't remember) to '79 was the marine cam. Dang, thats a weak torque peak....

dyno2000 is a computer program that you can plug in information about your car's engine, and it will estimate the hp and torque curve. It has since been updated and is know called DynoSim. I'm not saying this curve is dead on, but the software generally will give you a fairly good estimate. It's very good for seeing what certains cams could do for your engine, because you can just keep entering the stats for different cams and see what it might do for you. And it's much cheaper than going out and buying the cams and actually trying them.

I have that program, and a buddy had the original incarnation on his ancient tower. Some things that limit the program is the assumptions made by the programmers. In one case my buddy plugged in a pontiac mill and the program 'over estimated' the mill's potential because of the assumption of tulips vs. nails for valves.

It does show the correct 'corrections' in the curves when you apply all the 'cam' rules of retard or advance you cam 4 degrees, and if you widen the LSA your torque curve comes on lower at the expense of the top end (and vice-versa if you narrow it up to 104-106 you get good top end...of course this can also be 'fooled' with when using a short vs. long duration cam too...)

The other flaw is the program takes a good guess on the intake volume and thinks that more is better and 'lots' gets you some big increases....I don't think my 225 is going to see much difference in airflow used between the 600 cfm Holley I have and the 1000 cfm throttle body I eventually will be adding...yet Dyno 2000 seems to think it's worth another 25HP.

I also like the fact it only displays the power curve above 2000 rpm....most street driving occurs from idle (750-1000 rpm) to 3000 rpm (4500 if you have a Hpak and are looking to whomp the Nova sitting next to you....), with maybe some drag racing rpms in the 5500-6000 range.

It's a good 'bench racing' program to see what changes may 'help' you, but take the info with a grain of salt...

-D.Idiot

Very well said, DI. I am very skeptical of these things in general. Basically, the more variables it includes correctly, the better it will be.

BTW, I don't like driving below 2000 rpm.

Lou

_________________
Home of Slant6-powered fun machines since 1988

Thanks for the info.

If it is not to much trouble. Could you run one more set up I am thinking about?

Holley 390cfm 4bbl, offy intake

comp cam 252 duration with .425 lift

My thought was to do this and revalve the head with 170 intakes and 144 exhaust.

The stock exhaust manifold is water jacketed and would be a pain to modify. on the plus side, it runs into a 3" straight exhaust.

This is in a boat and I need more low end torque then a car would.

If any one has run this set up before, I would be thankful for any input.

Mr. creamedpossum thanks for the help.

I forgot, I would also mill the head and up comp ratio.