How fast is my 1990 21 Cougar? 2.5 Merc MAD EFI injection

[RUNWME]

I tried out my 21 Cougar tunnel today with a new engine combination of a Tommy Dunn modified 2.5 Merc with Wayne Taylors MAD EFI injection system on it.

I didn't have a GPS with me, but it was running 8250 rpm spinning a 26 pitch Mazco Chopper fully loaded with 2 210 lbs guys and full fuel. It has a BridgeportCLE gearcase.

This is fully adjustable injection, and ran good right out of the box with the mixture turned about -10% on mixture.

How fast was I running? Any idea what this boat weighs?

David

[outboards4life]

from what I got with 12% slip. you were running 95. if you have 1.87 gear ratio in it.
lata
Travis:cool:

[David]

1998 Cougar brochure lists the bare hull weight at 630 lb

[WATERWINGS]

David,

My chart shows, with 10% slip, 97 MPH.

If you have any cup rolled into the prop, speed should pick up.

[RUNWME]

I emailed Cougar Boats and they said my 87 21 MTR weighed 2200 lbs completely rigged sitting in the water. 2 guys weighing 210 each on board puts me at 2620 lbs! wow, I was thinking it was lighter, but I am not complaining as it sure rides good in rough water.

Thank you guys who checked the math and came up with approximate speeds. I am betting with the weight of the boat and me running the engine high my slippage will be higher and my speed somewhat slower. The water pickup speedometer puts me at 92 mph, but it is usually generous.

We will know when John puts his radar on me or I carry a GPS on board.

[Raceman]

RunWme, here's an online speed calculator that's a lotta fun to play with. For gear ratio all you have to do is type in 1.87 (or whatever your's is)

http://www.rbbi.com/folders/prop/propcalc.htm

[RUNWME]

Cool calculator. Lets see, if I add nitrous I should be able to swing a bigger prop... hmmmmmm a 28 chopper at uhmmmm 9000 rpm with .1 slippage that should put me at approx 114 mph...... now, lets say I mix nitromethane and alchohol, then reprogram my fuel curve... turn a 32 prop at 9000 rpm I am at uhmm WOW !! 131 MPH !!

Raceman, I can see this calculator as a "dangling carrot" out there for me. Urging me to try things I shouldn't and emptying my wallet of $$ and my engine cowling of parts as they exit stage left! Actually can say that about the scream and fly site, checking out others hot boats and their speed numbers caused a burning desire in me.
This site caused me to sell my 1982 inline 6 dixie that burned 15 dollars in gas all weekend and purchase one hot boat after the next in an increasing need for speed. I went from having a Dixie boat that only had annual oil changes, water pump and plugs to these fire breathing Mercurys I keep burning up (hopefully thats fixed with programmable ECU)
I ride on a river, and invariably I will stretch it out traveling 5-6 miles at wide open speed getting bugs in my teeth wearing a big grin until WHAM there goes another engine. Then I am parked until I save the money up to buy new pistons, rings, sleeves, crank ect...

While everything is running good, I am loving life, but when that time comes and I am being towed back in... the entire time I am thinking "SCREAM AND FLY!! ERrrrr (me growling) I wish I had my dixie back!! " I could be happy with only running 51 top speed.. right??
NO WAY!!

Ya see, having experienced the speed, I would never be happy owning something that wouldnt run 70 mph. You guys have given me the bug..... Now, do you know where I can get some nitromethane and nitrous kit??