racinfever

Ray you are so RIGHT ! In the future (next year) we are looking at high fuel prices & low octaine fuel only . big cams & blowers will no longer be practical , low boost motors or N/A motors will have to rely on peak efficiency to make real power. more thought to cam profile cam timing cyl head design. instead of lets see how much fuel and air can we shove to it. Ive been running a 555 inch tunnel ram motor for nine years , it makes 720 hp 740 lb torque 5600 rpm 89 octain only , idles great , & gone 450 hours between rebuild. these motors are user freindly and make great power, they power my 38 fountain (8800 )lb 92 mph with decent fuel consumption !

gg10

sonic, I would suggest raising static cr to 10-1, swap your dart intake out for a edelbrock victor, reasonable price and makes more power below 6000 , run a larger cam and you might be supprised what you gain. The biggest problem I have had in making power in the boat na is exhaust. I have run quite a few of the marine system in the boat and on dyno and they wouldnt pull the hp, I made a set of headers that would pull the hp in the boat, they are 2.375" for the first 10", then step to 2.5" for the balance of the 38" primary length. then they go to a true merge collector and 4.5" tail pipes. I would look at this type of system if you want to make power in boat. gg

RumRunner

This can be done, but at what cost??? If you're spending an additional 10G or more to get another 40 or 50 HP is it worth it? It is all in the perspective of the person, (and their wallet) working on it.


As far as the marine exhaust thing goes, we ran into a situation with an engine builder on some customer engines where he couldn't duplicate the power. Turns out when they dyno tested originally the only headers he had were a set of Custom CMI's that were built for a specific application. The off the shelf stuff was down a bunch on fuel flow, and HP. Showed everything to the end user who decided the power was good enough (Couldn't justify another 20G for exhaust).

jdnca1

You don't have to run a solid roller to make power, but you have to run a solid roller to MAXIMIZE power especially with larger CI NA power. A solid roller will start eating up a hydraulic equiv above 5000 rpm, with the advantage growing exponentially every 500rpm thereafter. Its simply mechanics of being able to accomplish the same at a faster pace...IE valve stays open longer....big inch motors need lots and lots of air.

looks like 100LL with 2 stroke oil will be the alternative if 93 goes away.

jdnca1

[QUOTE=RumRunner]This can be done, but at what cost??? If you're spending an additional 10G or more to get another 40 or 50 HP is it worth it? It is all in the perspective of the person, (and their wallet) working on it. QUOTE]

Exactly, which is why at some point it makes sense to go with forced induction over NA to pick up the power you are after. There are always trade-off's.

Raylar

Yes 91+ Octane fuel is mandated to disappear under the Federal EPA rules in place for implementation in 2007. Not only will 91 octane be the max as standard pump gas high octane in every state who wants federal money and beleive me none can live without the Feds money!, but the fuels will also be oxygenated with alcohol additives and such to as much as 30% additives for emissons requirements in all 50 states! Good luck with any motor with more than 10.to one compression.

Ray @ Raylar

GPM

Will the E85 be any help? what about water injection?

RumRunner

Pros & Cons to E-85!

Pro: Claim to be 105 Octane!
Pro: Helps eliminate detonation
Pro: Less expensive!

Con: 9:1 A/F instead of 12:1 Means you need to burn 33% more fuel to be the same. Say good by to any range
Con: It is a dryer fuel that gas, and can absorb moisture (Probably not a real good idea in marine environment)
Con: Use 33% more fuel, will actually cost you more in operating costs.

soinc

well no 93 octane fuel is a bummer !!! hey I wonder is this is a north american thing or just in the USA hum it may be good to buy my fuel in CANADA!!

as for the wallet 1800/side cam,springs,push rods & rockers to beat your hi profile neighbour = pricless

tunnel ram, carbs, angle milling .ect another 2500-3000 side
going though xr's like there candy = worthless
I'll be out of the water more than I'm in it.and I'm very easy on drives 0 losses

so in short... solid roller,shaft mount rockers,and related items is where were going to go...

thank you guys this is the most replies I have ever had!!! you rock!! oso members...the best!

soinc

Rumrunner well your tuned in need to ask you which fuel (eletric) pump you recomend in a boat application that will suply my HP there is like 3 diferant pumps that flow 220 gph that you guys offer.
and dose a regulator with a return need to be run? with this set up?
thanks Shawn