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Old 08-08-2009, 09:22 PM   #1
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Should I? What do you think?

Hi everyone!!

Just sitting up here planning my winter work out and just wondering.....

I've got a Fletcher 21 with a Mercruiser engine (not sure which version as the previous owner(s) have gone mad with paint), anyway I'm just thinking about the cost of fuel etc. and am wondering if its worth rebuilding my existing V8 gas guzzler or replacing it with a smaller turbocharged engine, for example a Volvo 2.3 (boosted up to 250+ BHP) or should I stick with the V8 and buy shares in BP?

I'm mainly planning to use the boat for cruising around the North West with runs to the Ilse of Man and a bit of water ski-ing / towing toys etc, but am wondering if a smaller turbo'd engine will produce the necessary torque. I know I'd have to sort out cooling etc, but just wondering if any of you have any thoughts or suggestions on this.

Thanks
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Old 09-08-2009, 03:42 PM   #2
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wouldent a smaller turbo'd engine only produce the torque required when its at higher rpm, if the boost is high then lag may be an issue for towing skiers, plus the fuel usage cant be that much higher on the v8 can it?
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Old 09-08-2009, 08:29 PM   #3
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wouldent a smaller turbo'd engine only produce the torque required when its at higher rpm, if the boost is high then lag may be an issue for towing skiers, plus the fuel usage cant be that much higher on the v8 can it?
Hi Scooby,

Yeah this is the dilema I've got. Do i go for a turbo'd engine which as you say will produce the torque at higher RPMS or a 'lazy' V8 which will produce it lower down but could loose out at the top end. You're right of course, the turbo kicks in at around 2500 - 3000 RPM which sounds high compared to the V8 but I'm planning to use a vari-pitch propeller and I think that should be ok. To be honest I'm not to worried about the lag involved as I'm not a competitive boarder by any stretch of the imagination ( I have a record for breaking legs on snow!!!) but I'm just thinking about the overall problem including fuel costs because we have to keep the government in its safe cosy little ivory tower and how else would it keep UK PLC going without fuel duties (at this point the doctors arrive and use a sedative. Dr Nick says ".. it's best not to start him off on this rant..")

Thanks for your input Scooby!!!
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Old 09-08-2009, 11:55 PM   #4
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i suppose it would come down to which engine will burn the fuel more efficiently to make the same power, also i dont think a smaller turbo'd engine will enjoy being held at constant high rpm for extended periods and all its power is going to come in at the high rpm, if your going the small turbo engine route have you considered a yb cosworth, very strong engine and it has massive tuning potential, you can get one out of an old sierra cos quite cheap these days
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Old 10-08-2009, 08:41 AM   #5
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If the V8 has a carb, then I would consider putting fuel injection on it, someone else may be able to give you fuel efficiency comparisons, but I'm sure it would help.

Is this other motor marinised? If not you are in for a whole lot of work to make it happen - if it's an ally block you have to have a heat exchanger, and sort out exhausts etc, so not a simple job at all. The other thing to consider is if this motor isn't used in marine applications there is probably a reason for it!
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Old 10-08-2009, 08:47 AM   #6
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The other thing to consider is if this motor isn't used in marine applications there is probably a reason for it!
I was just about to make that point. If small turbo engines were the solution to amazing power and amazing economy in a boat, don't you think all the manufacturers would be using them by now?
If you just want to try something different, go for it. If you're actually looking to save money, stick with the standard stuff.

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Old 12-08-2009, 08:03 PM   #7
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Cookee, yep its a carb unit. Not really though about fuel injection - good call I'll look into this option.

Scooby Hugh - Yeah I looked at the Cosworth engine as well as the Volvo 2.3 Turbo from a 940. Both good strong engines with plenty of tuning potential, but as larby rightly points out marinising them would be a major pain - I've got a heatexchanger manifold from my old Pinto engine that lurked in another boat ( i love collecting weird stuff) but unless I go into major engineering, I think I'll pass!!

Thanks for your input folks, much appreciated. I'll let you know how what I decide and how it went on!

PS I could always drop a supercharger on it !!!!
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Old 13-08-2009, 10:32 PM   #8
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User Name

Is this LoZ?
I am confused why do you have the same user name as Captain Chaos?

Surely you must have noticed our very own Capn on board already?

Strange!
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Old 13-08-2009, 10:40 PM   #9
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nah............. isnt me cye
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Old 13-08-2009, 10:56 PM   #10
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Is it a thin serious person?
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