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which way to go

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which way to go

Postby terzi » Sun Jan 30, 2011 3:13 pm

I know it's all about greenbacks, but here's what i want to discuss.
i have a 383 and i want more power. it's got 40 hours on it. assuming i have the ability to build it, should i sell it and go with with the factory lsa for 20g's or build and supercharge (or just build) what i got. I know ther're a lot more knowledgable guys on here than me. give me your thought on this.
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Re: which way to go

Postby dustin » Sun Jan 30, 2011 4:35 pm

the LSA is about 15k and you better do your research. there is a motor mount problem and you will need to change some wiring. i dont know the specifics on all of it though.
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Re: which way to go

Postby Hell Yes » Sun Jan 30, 2011 4:41 pm

Put a super charger on the 383 for half the money and probally get the same or better fuel economy. Build the 383 up to 550 hp.
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 4:50 pm

dustin wrote:the LSA is about 15k and you better do your research. there is a motor mount problem and you will need to change some wiring. i dont know the specifics on all of it though.



chris at mp quoted me 20g's maybe i should shop around. mp's web site says this it's compatible with analog gauges (which mine is) am I off the mark on this?
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 4:57 pm

Hell Yes wrote:Put a super charger on the 383 for half the money and probally get the same or better fuel economy. Build the 383 up to 550 hp.


with the longer stroke, should i drop the compression from the factory 9.1 to make it last or would this be ok.
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 5:05 pm

terzi wrote:
dustin wrote:the LSA is about 15k and you better do your research. there is a motor mount problem and you will need to change some wiring. i dont know the specifics on all of it though.



is the wiring difference more related to the connection to the ecm and the related sensores that the 383 doesn't have.
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Re: which way to go

Postby MTRiverRunner » Sun Jan 30, 2011 6:46 pm

You can build one heck of a motor with that 383. It is going to cost you though. 5-7K for a supercharger. A supercharged, intercooled HT 383 (the crate motor that MP and KEM use) will turn a 3.4 KW impellar 4200 - 4300 RPM from what I have seen (running only 5 psi boost on a centrifugal supercharger). You will need to build the motor a lot more to get anywhere close to the performance of an LSA (4.0 KW @ 4500 - 4600 RPM).

I had a KEM 383 in my last boat. My new boat has an LSA. The LSA is much smoother and the fuel economy isnt much worse. I keep EXACT track of my fuel economy, I keep a spread sheet with hours and miles run, etc. Eventhough my new boat is much bigger than my old one with the 383, I only use 1 gal/hr more fuel on average (that number really isnt fair because I carry much more crap with me now). I would venture to guess you are going to burn WAY more fuel with a built 383. Some will tell you that they do better with their 383s, I am just telling you what I have learned from beign super anal about my fuel economy numbers and nailing it down to the 10th of a gallon. The old SBC archatecture is way less effecient than the new LS based motors. I am very impressed with the fuel economy in my LSA, I have compared it to other people's #s with 8.1L and it is really close.

I think that an LSA is going to be closer to 20K, unless the price has come down in the last year.

Another bonus, the LSA is substantially lighter than your iron blocked, iron headed 383.
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Re: which way to go

Postby 792 » Sun Jan 30, 2011 6:57 pm

How about the ls3?
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Re: which way to go

Postby HaxbySpeed » Sun Jan 30, 2011 7:00 pm

I don't think you'll find an LSA for 15k, but you can do better then 20k for sure. I can give you a quote if you're interested and could take your 383 on trade depending on what year and condition it's in. On the other hand adding an intercooled procharger kit to your 383 will run just over 4k with an ecm recal. With 9-1 comp you can make 450hp on 91 octane and 500hp on 93. That'll wake er up! :Power:
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Re: which way to go

Postby BigCSS » Sun Jan 30, 2011 7:03 pm

MTRiverRunner wrote:You can build one heck of a motor with that 383. It is going to cost you though. 5-7K for a supercharger. A supercharged, intercooled HT 383 (the crate motor that MP and KEM use) will turn a 3.4 KW impellar 4200 - 4300 RPM from what I have seen (running only 5 psi boost on a centrifugal supercharger). You will need to build the motor a lot more to get anywhere close to the performance of an LSA (4.0 KW @ 4500 - 4600 RPM).

I had a KEM 383 in my last boat. My new boat has an LSA. The LSA is much smoother and the fuel economy isnt much worse. I keep EXACT track of my fuel economy, I keep a spread sheet with hours and miles run, etc. Eventhough my new boat is much bigger than my old one with the 383, I only use 1 gal/hr more fuel on average (that number really isnt fair because I carry much more crap with me now). I would venture to guess you are going to burn WAY more fuel with a built 383. Some will tell you that they do better with their 383s, I am just telling you what I have learned from beign super anal about my fuel economy numbers and nailing it down to the 10th of a gallon. The old SBC archatecture is way less effecient than the new LS based motors. I am very impressed with the fuel economy in my LSA, I have compared it to other people's #s with 8.1L and it is really close.

I think that an LSA is going to be closer to 20K, unless the price has come down in the last year.

Another bonus, the LSA is substantially lighter than your iron blocked, iron headed 383.

I talked to the MP rep (I believe it was Chris) at the Portland Show and was asking him what the actual marinized wet weight (full of oil and coolant and all marinizing parts) of the LSA was and he told me it was 75 lbs heavier than a 6L VVT is. He said the LSA is 750 lbs wet. I don't know what a 350 or 383 weighs wet or marinized though.
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 7:08 pm

what octane level does the lsa like? btw my motor is 2009 put into service may 2010 with 40 hrs. through the summer. of course sitting at the moment (-13 here right now).
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Re: which way to go

Postby HaxbySpeed » Sun Jan 30, 2011 7:13 pm

about 800lbs
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Re: which way to go

Postby HaxbySpeed » Sun Jan 30, 2011 7:16 pm

terzi wrote:what octane level does the lsa like? btw my motor is 2009 put into service may 2010 with 40 hrs. through the summer. of course sitting at the moment (-13 here right now).


They need 93 octane, there are guys out there running them with less boost on 89 but the performance and fuel economy stinks..
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 7:50 pm

792 wrote:How about the ls3?


the ls3 is an intriguing option especially for my jet but i don't know if it will get over the hump so-to speek. i run 4 grand now and want to turn it into 5 grand or a least the peak of the engine i'm running. i don't think the ls3 will reach its max without impellering down a bit and loosing low end thrust.
i could be wrong though ;)
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 8:01 pm

HaxbySpeed wrote:I don't think you'll find an LSA for 15k, but you can do better then 20k for sure. I can give you a quote if you're interested and could take your 383 on trade depending on what year and condition it's in. On the other hand adding an intercooled procharger kit to your 383 will run just over 4k with an ecm recal. With 9-1 comp you can make 450hp on 91 octane and 500hp on 93. That'll wake er up! :Power:



is the octane requirement relative to the boost or is more closely related to how much hp the thing is puting out. in other words, if i add additional boost from a procharger from 5 to 7 lbs will the octane requirement be the same as building the motor up to begin with and then stay with 5 lbs of boost.
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Re: which way to go

Postby MTRiverRunner » Sun Jan 30, 2011 8:06 pm

GMs website lists the 6.0 L VVT as 539 lbs and the LSA as 467 lbs. That makes the LSA pretty light since that includes the supercharger and intercooler. Of course you have to add an additional heat exchanger to feed the intercooler which adds additional weight. GM also says that premium fuel is "reccomended but not required" for the LSA. It has a knock sensor and will retard the timing if you run lower octane fuel. THat said, I wouldnt really reccomend doing that. But if you were in a pinch you could get back to the trailer.
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 8:23 pm

MTRiverRunner wrote:GMs website lists the 6.0 L VVT as 539 lbs and the LSA as 467 lbs. That makes the LSA pretty light since that includes the supercharger and intercooler. Of course you have to add an additional heat exchanger to feed the intercooler which adds additional weight. GM also says that premium fuel is "reccomended but not required" for the LSA. It has a knock sensor and will retard the timing if you run lower octane fuel. THat said, I wouldnt really reccomend doing that. But if you were in a pinch you could get back to the trailer.


isn't premium at the pump 90 or 91 octane? i don't use it enough to remember.
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Re: which way to go

Postby HaxbySpeed » Sun Jan 30, 2011 8:29 pm

terzi wrote:
HaxbySpeed wrote:I don't think you'll find an LSA for 15k, but you can do better then 20k for sure. I can give you a quote if you're interested and could take your 383 on trade depending on what year and condition it's in. On the other hand adding an intercooled procharger kit to your 383 will run just over 4k with an ecm recal. With 9-1 comp you can make 450hp on 91 octane and 500hp on 93. That'll wake er up! :Power:



is the octane requirement relative to the boost or is more closely related to how much hp the thing is puting out. in other words, if i add additional boost from a procharger from 5 to 7 lbs will the octane requirement be the same as building the motor up to begin with and then stay with 5 lbs of boost.


Several things effect the octane required, valve timing, compression ratio, hp vs load vs rpm, engine size, etc. For your stock configuration the hp/octane requirements I listed will keep your engine safe. You could make 500hp on 89 octane but you'd have to make some changes. What jet are you running?

Most modern EFI engines with knock sensors reduce timing and add fuel to keep out of detonation, prolonged operation like this is a baad plan but like MT said, it'll get you back to the trailer and keep your engine alive if you get a bad tank of fuel.
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Re: which way to go

Postby terzi » Sun Jan 30, 2011 9:00 pm

i have a scott jet (852). the reason i'm qizzing about this octane stuff is that i don't know if 93 octane is that available to me. I was thinking the local chevron premium is like 90 or 91. I also worry that the 383 is prone to knocking to begin with so adding even more stress concernes me a little. I guess taking out some timing would help that problem?
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Re: which way to go

Postby HaxbySpeed » Sun Jan 30, 2011 9:29 pm

Chevron should have 91, they have 94 up here, you'd be fine @5lbs boost with 91. The Vortec heads have a very efficient combustion chamber and don't require a lot of timing anyway. The 383 isn't any more prone to detonaton then a 350. With the Scott pump you could definitley utilize the power/rpm of the LSA but you'd still need 93 octane to make it worthwhile..
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