easy 2-3 mph
 

for you guys that have messed with a 25 tantrum.raced my buddies 25 checkmate with 502 mag and we are dead even.anything quick and cheap i can do for a couple mph.stock 454 mag carb.could only spin my 25 mirage 4500 rpm.could lab it for 200 and would like another 2-300 rpm.thinking of emi thunder exhaust.would this help or should i put the 1500 somewhere else.and please don't say blower

I hear that the----
 

Emi thunder is good for 25-30 HP, not sure how much more speed, labbing will help, what about a set of headers out of the classifieds I would think that would be your biggest gain..

Save some money, buy the Revolution Marine exhaust, get a good air breather, have your prop labbed, look at your balance and make sure you're not using your left tab too much, run some good higher octane fuel and advance your timing, take ALL the excess weight out of your boat, check your skeg for notches, chunks or other problems that may effect hydrodynamics, take off your speedo pitot pickup,
I can think of a few othere, but start there and see how things work...

Hey...you sound like you know WTF your talking about!!:D

gordo how much timing can you go with higher octane fuel.sending my prop out to bblades today.not sure which exhaust i will buy.i like the emi,should just supercharge and be done but had alot of problems with my other boat with a blown smallblock.thanks for the input

Gordo, RM over Stainless Marine?

For the money, you Can't beat the revolution Marine exhaust. The engine guys may have a more exact number for you, but running 94 octane or so @ about 40* total advance seems to work well. Anything more than that (fuel octane or timing) seems to be wasted due to the low compression ratio. The balance/weight I mentioned refers to the boat leaning to the left due to prop torque, load balance and other issues that cause drag or poor handling. Keep in mind, these are all things that will help you a half a MPH at a time. Add them all up and you can get a couple of MPH for free.
A great friend once told me, "It's not always how fast you go, but how you go fast".

<laughing> I read a book once....

WOW......I can't read, I just look at the pictures:D

Gordo is also referring to balance, as make sure the fat guy to your left isn't throwing the balance off either. Ha Ha....

I do agree the exhaust from Revolution is really good compared to EMI. Never had an opportunity to compare it to Stainless Marine thought. Probably pretty comparable.

A.B.

i just remember when i was shopping, fred/trick discussed the RM may not be the best choice in salt water. As far as price, they are as inexpenisve as you get for a quality product.

<LMAO!> Since you always kept the throttle pushed through the forward bulkhead, I think it all evened out. :eek:
Revolution Marine and Stainless marine exhause are both quality parts and very comperable in performance gains. The stainless risers do look cool, but the larger ( I.D.) cast risers on the Revolution Marine exhaust actually performs just a little better.
As for salt water, I think ALL the cast aluminum exhaust manufacturers strongly recomend thourough flushing after every run. For that matter, any exhaust, whether they are cast iron, cast aluminum or stainless steel, salt is cancer no matter how you look at it.

Have you ever seen a RM cast aluminum set after a couple years in any water, salt or not? Cast aluminum is cheap chit!
Go with Stainless!

Sounds like there were other issues involved with your experience. I've sold a number of RM exhaust with no problems, corrosion or otherwise...
Fact is, if you run in salt water and don't flush after each use, you will have problems with any exhaust whether it is cast or stainless.

Cast aluminum is even worse on a lake with a powerplant that puts a negative ion charge on the water.

I had MANY a problem with this on PWC back in the day when running on Lake Anna, VA. Lake Anna is a man made lake to cool a nuclear power plant, and it will literally cause the cast aluminum to molecularly come apart.

Cast aluminum just won't last like stainless, looks bad in under a year. I rarely boat in salt water, but if I do I flush, wash, rinse, flush again and then....I rinse and flush again!!!! Always have, always will. Salt is Cancer, period.

You got me on this one. The only powerplant lakes around here are smaller fishing lakes, so I don't have any experience with equipment in these conditions.

Supercharge
 

I say supercharge that thing and put that checkmate in its place I think the M3 or M5 procharger would be perfect I am running them they are very effecient, make huge power, and I have had zero problems with them...of course I am typing this with one hand and knocking on wood with the other..

:D :evilb: :D : Not dead even anymore except when I have a boat load of fat guys.....:p