turbo charging a mercury

[droptine150]

does anyone know if there is a manufacturer that makes a turbo charger for small outboards like the 25hp? i have a 2006 mercury efi 25hp fourstroke and was wondering if somebody had any suggestions. they make the verado why not make a small version?

 

[Silvertip]

Re: turbo charging a mercury

1) The Verado is "super-charged" not "turbo-charged". 2) Cooling water exits an outboard through the exhaust. Since a turbo-charger requires exhaust to develop boost, don't you think water might raise heck with the turbo? That's why it's not done -- on outboard or inboards (unless dry stacks are used). 3) Who in their right mind would spend a grand or more to boost a small engine to perhaps gain 50% power while at the same time decreasing reliability when for the same money you could upgrade to a larger normally aspirated engine and have the usual reliability. A turbo and its associated plumbing would result in adding a considerable amount of weight and bulk as well. May as well have a bigger engine.

 

[Frank Acampora]

Re: turbo charging a mercury

Amen!

 

[kenmyfam]

Re: turbo charging a mercury

And so say all of us !!!!

 

[madgadget]

Re: turbo charging a mercury

25hp 4 stroke could easily be turbo'ed lol, ok it may be pointless but it would be cool haha.

What kind of engine capacity do those have? 600-800cc? A turbo from a Smart Car (If you get those over there) would do the job, You would have to know about EFI however and change the ECU on it and map it accordingly. You can get oil cooled turbo so that would be ok, and there would be lots of small hurdles to get over, but it is do-able.

My day job consists of turbo charging/mapping performance tuning road cars, so I do this kind of thing all a lot.

Yeah to some its pointless, but its a whole living to others. I have a small car which has an inline 4 cyl engine, supercharger & turbo charger its 8b 930cc and produces 200hp and 200lb/ft of torque. The car weighs less than 1700lb with me and half a tank of fuel in it !!

 

[Silvertip]

Re: turbo charging a mercury

You still miss the point. Exhaust on an outboard is has water in it because that's how it gets out of the engine -- it is not a closed cooling system like a car. That exhaust drives the turbo. How long do you think the turbo would would last with water flowing through it.

 

[steelespike]

Re: turbo charging a mercury

About how many hours could the 930cc motor run when driven continously at full power?I have a feeling signifigantly less than that of a normally asperated motor.

 

[Silvertip]

Re: turbo charging a mercury

Actually, boosted motors can last longer than normally aspirated engines because there are far less "pumping" loses. Neither engine will live a long life if continuously operated at wide open throttle - but that too depends on what RPMs each engine is turning at wide open throttle. Boosted or not, an engine running at 4000 - 4500 rpm will last much longer than one running 6000+. It all depends on state of tune and amount of boost. I have a friend whose daily driver is Pontiac with a boosted 3.8 V6. He is closing in on 300,000 miles with nothing other routine maintenance.

 

[Frank Acampora]

Re: turbo charging a mercury

And the last point that everyone missed is that the BACKPRESSURE necessary to power a turbo will blow back into the exhaust ports and probably reduce the power to a level below stock! Turbo is NOT do-able without very special modifications on a 2 cycle-- why do you think it has never been done on the Japanese dirt bikes--they ALL use tuned pipes.

Even the old Detroit Diesel 2 cycle bus engines were SUPERCHARGED, not turbocharged. Where do you think the NHRA dragster used GMC 3-71, 4-71, and 6-71 superchargers originated? Detroit Diesel!

 

[Dhadley]

Re: turbo charging a mercury

It's very possible to turbo charge an outboard. Either 2 or 4 stroke. There were turbo kits for larger 2 stroke outboard motors 30 years ago. They worked OK but were very sluggish on acceleration. To overcome that they used nitrous for the initial acceleration. It never really caught on, too many issues including size.

Inboards and IOs have been turbo charged for much longer than that. Those kits date back to the 70s, maybe older than that. Twin turbo'd IO and inboards were not that rare back in the day.

 

[cribber]

Re: turbo charging a mercury

You could go this route if you had an I/O... not sure how you'd shoehorn this into a 25 hp OB setup.

http://www.procharger.com/M_engine.shtml

Procharger makes a centrifugal supercharger for marine setups. Expensive to go from 25 to 37 HP... not too bad if you're going from a stock 350 at 280 hp to over 400 HP.

 

[madgadget]

Re: turbo charging a mercury

lol I love threads like this.

The engine lasted 98,000 miles. I'm rebuilding it now using a longer block, increasing the capacity to 1255cc, have a bigger turbo, doing head work and significant changes to the overall pipework and coolign system and I aim to exceed 300bhp. The engine complete with all ancillaries weighs around 240lb...

Anyway, This this is for a 4 stroke OB as the OP said in the first post. I am not fully aware of the layout of one of these engines. However I still stand by that its not remotely an impossible job. If he wants to lend me his engine I'll do it for him hahaha.

 

[Dhadley]

Re: turbo charging a mercury

The Procharger has been around a number of year and is very successful. We're working with a guy right now on props that has a 470 Mercruiser (4 cylinder) with one. It'll be very interesting to see how much more pitch he'll need.

 

[cribber]

Re: turbo charging a mercury

I'd love to see what improvements I'd get on a 3.0 Penta 4 banger plumbing in a Procharger system. Since they don't offer this for 3.0l engines, I wouldn't want to be the guinea pig building this out only to blow up my motor. I'd be in sooo much trouble with the Mrs cuz I took away her boat time.

 

[Dhadley]

Re: turbo charging a mercury

Blowing up the motor won't be the isue, the drive will be. My guy claims his 470 is over 325 hp, stock 470s are something like 170 hp. He didn't change the gear ratio but that's his choice.