Mercury Racing 600 SCI Fuel Consumption
 

Hi,
Can you help me out on this, I have a pair of Mercury Racing 600 SCI's producing 750BHP each what fuel consumption should I expect to get at full revs of say 6,000 rpm, The boat is a deep "V" and weighs in at 6000Kg

thanks
Martin

.2mpg

Wow wasn't expecting the fuel consumption to be that high, was there a formula that you used?
Thank you
Martin

Pash1:

The only way to know your exact mileage (fuel consumption)at that horsepower level(much higher than stock 600sci) and that rpm is to hopefully have the engine dyno test sheets and hopefully the BSFC (brake specific fuel consumption in lbs./hour) on those dyno tests and calculate your mileage.
You can assume that raising the horsepower by 15% or so you have and taking the top rpms up by over 500 rpms you will be greatly increasing the fuel consumption per hour versus a stock 600sci engine.
This does not appear to be a project where fuel mileage was the primary concern?

Best Regards,
Ray @ Raylar

I always calculate gal/hr myself not miles per gallon.My friend has a 1998 35 Fountain with steps, twin 600's [ with blowershop blowers, 4 carbs] using roughly 50gal/hr ea engine at WOT.
The 6.2 MX MPI's in my 25'7 boat register 25gal/hr ea @ 5150 WOT on the Smart Craft flowmeter.

Thanks Raylar for your information, I bought the engines with 6 Hrs on them and was told that they dyno'd @750 BHP with a stage 2 Wipple, I guessed that it would top out @ 6000RPM as that is the rev limited fitted, Just wanted a rough idea of the fuel consumption as hopefully going out testing before a race here in the UK. I have 300 UK Gallons on board - No fuel gauges, I was reckoning on about 150 UK Gal per hr or in your terms at our Gas prices $2,350 per Hr :eekdrop::eekdrop:

are you planning on running wide open for hours on end ?

if you are, the cost of fuel will be meaningless compared to the cost of rebuilds

Ain't that the truth. The fuel will be the least of your worries if you run them WOT for hours on end.
Eddie

Martin:

Most of the racing venues and pictures I have seen from the UK the sea conditions will not allow a boat to run a 6000rpms for many long periods., but that being said, my guess would be at that 6000 rpm and horsepower number with that Whipple stage 2 upgrades I would guess those engines are gonna use at least 60-80 gallons per hour EACH! maybe more. You might Email Dustin @ Whipple or PM him here on OSO and see if he has data from his dyno tests on these engines with that he can give you exact figures for the fuel use at that rpm and horsepower level. He is very exacting and thorough with his testing and measurements. I think he might be a great resource here.

Best Regards,
Ray @ Raylar

Thanks Ray,
Best advice over here was 0.1 UK Gals per BHP Per Hour so we are in the right field....
Martin

Rev CAUTION!
 

Watch your valve train like a hawk! Mercury never intended these engines to run 6,000 rpm. If they're stock 600SCi heads, they were rated at 5,200 max. At 6,000 you will frequently replace rockers, springs and valves -- if you are lucky. Pistons, rods, cranks and cylinder blocks are likely, if your engine swallows a valve.

http://mercuryracing.com/sterndrives/hp600sci/specs.php

Your HP divides by 12 will give you a good estimate. 750hp/12=62.5 gallons per hour at WOT. That is per engine.

I have a single 600 sci stage 2 whipple. I am very happy with it and have had it for two years. I guess I should say happy except for fuel consumption. I don't have a formula but here is a good one. Keep your wallet handy!

VERY accurate, according to Smartcraft on my 600sci's with Whipple Stage 2 upgrades.

Have heard of issues spinning stock valvetrain too high, so re-geared to keep just above the stock 5400 limit. The last 25 or so hp achieved by the extra rpm is not worth the loss in reliability.

Rev limit is 5850, 400 more than stock. I'm not sure you have to watch it like a hawk, that seems a bit extreme. They should be inspected more regularly than stock, but by no means all the time.

Thanks Guys very Handy information...