Northstar repower?

[45Auto]

Re: Northstar repower?

His profile says he currently has a 1976 Apollo with a 4 cylinder in it. He said he's going to put the caddy motor (or the HP1200SCI if I can talk him into it) in another boat though.

 

[fabrimacator21]

Re: Northstar repower?

I don't believe you or me are gonna be able to find any numbers on a 6.0 in a boat but....

In a truck they (the 6.0) has been known to get 17mpg on the freeway and 14-16 in town.

The 496's get anywhere from 8mpg to 13 in town and 13-14 on the freeway.

Just speaking from personal experience....

The whole theory of "it doesn't matter what the CID is... it takes the same amount of gas to make the same power" is false... it depends on how effeciently the engine burns fuel.

Also drive a 454 chevy truck and then drive a 350 truck. We had a 454 chevy truck at 2 places that I worked at and they'd average about 8-10mpg in town.... the 350 trucks were around 14mpg. So if those two motors are in the same truck and getting different mileage then thats proof enough for me.

Hell even if the 6.0 got the same mpg as a 8.1l which it doesn't, you'd still have, lighter, cheaper, more common (cheaper hot rod parts), and higher revving to contend with. Also the 496 is a grunt monster but hp isn't all that impressive for its size... a 6.0 can get to well over 425hp with just headers and a cam.

I belong to a truck site and theres a guy on there who is basically the 6.0 guru. He took a stock lq4 6.0(the lower compression 6.0... rated at 325hp, 380 ft lbs), put headers on it with a tune from an escalade and made 390hp and 440 ft lbs. That is assuming a very modest loss through the drivetrain.

The 6.0 will also bolt to anything a gen I small block does....

I don't even know why we're talking about 496's anyways... that's a whole different VERY expensive I/O.

All I'm saying is that the 6.0's are THE best bang for the buck out there right now. Like I said you can get one complete for around 1300 with 40k miles on it. Thats a 350hp 400 ft lb motor(on a real dyno, not chevy's rating) for dirt cheap with 6 bolt mains and over 300 ft lbs of tq at 800rpm.

Dollar for hp and tq the 6.0 is the way to go... and that goes for hotrodding it too.

 

[mylesm260]

Re: Northstar repower?

I would be very interested if you have anything that shows where a 6.0L would be any different.

One thing to remember.

All those motors, with the exception of the outboards, have combustion chambers that were basically designed in the 70's.

Better combustion chambers mean higher compression and better thermal efficiency. Better thermal efficiency means better mileage.

Also, variable valve timing increase you're volumetric efficiency at any given RPM. This also increase mileage.

You want a real world comparison of this, go look at the gas mileage of a 1990 chev pickup with a 5.7 and compare it to a brand new chev pickup with a 6.0L gen IV.

sure there are other factors that effect mileage, but do you really think tire or transmission technology has increased THAT much over the years? 80-90% of the gains in MPG are in the engine.

 

[fabrimacator21]

Re: Northstar repower?

Also, variable valve timing increase you're volumetric efficiency at any given RPM. This also increase mileage.

.

Just to clarify the lq4 and lq9 6.0's don't have variable valve timing. The L76(aluminum block 6.0), LY6 (aluminum 6.0 just with variable valve timing and fuel management), L92 (6.2L aluminum cadilac motor with variable valve timing), and LFA (hybrid version of the 6.0 ) have variable valve timing and you will pay through the nose for it.... something like another $1200 bucks for a used motor over the standard iron block lq4 and lq9 6.0's.

http://en.wikipedia.org/wiki/GM_Vortec_engine

Just to pound the price difference between the 496 and lq4 6.0 into the ground...

here is a longblock 496.

http://cgi.ebay.com/ebaymotors/496-...904QQcmdZViewItem?rvr_id=&itemid=250451296904

here is a longblock 6.0

http://cgi.ebay.com/ebaymotors/Cadi...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories



both of those are without efi, ecm, coils, etc.

Here is the cheapest used 8.1 I could find... 41K miles

http://cgi.ebay.com/ebaymotors/01-0...r_Truck_Parts_Accessories?hash=item2a01aab35f


and here is the cheapest used 6.0 I could find... 37K miles
http://cgi.ebay.com/ebaymotors/2003...r_Truck_Parts_Accessories?hash=item414a00b179

 

[45Auto]

Re: Northstar repower?

The whole theory of "it doesn't matter what the CID is... it takes the same amount of gas to make the same power" is false... it depends on how effeciently the engine burns fuel.

Very true statement there. A gasoline engine is about 25% efficient. A fuel injected, computer controlled 496 might be at 24.93% while a fuel injected, computer controlled 6.0L is at 24.96%. In other words, you'll never see the difference in the real world. Did the graph I posted a few posts above not show up on your computer???

Also drive a 454 chevy truck and then drive a 350 truck. We had a 454 chevy truck at 2 places that I worked at and they'd average about 8-10mpg in town.... the 350 trucks were around 14mpg.

No question that UNLOADED the smaller engine will be better. Now hook a 10,000 pound trailer to each of those trucks to simulate the load in a boat and check the mileage. You'll find that they BOTH get 6-8 MPG. Don't be surprised when the 454 gets better loaded MPG than the 350.

My 3000 pound dual-overhead cam Saturn with a 4 cylinder gets 34 MPG around town, 37 MPG on the road. Do you really think it'll get the same thing with the 10,000 pound trailer behind it???

I belong to a truck site and theres a guy on there who is basically the 6.0 guru. He took a stock lq4 6.0(the lower compression 6.0... rated at 325hp, 380 ft lbs), put headers on it with a tune from an escalade and made 390hp and 440 ft lbs. That is assuming a very modest loss through the drivetrain.

I belong to a boat site where there's a guy who is the 496 guru. He took a stock 496 (the lower performance 375HP version, not the HO rated at 425 HP), put aftermarket thru-hulls and had the ECM reprogrammed and made over 600HP.

The above proves exactly what????

I don't even know why we're talking about 496's anyways... that's a whole different VERY expensive I/O.

I don't know why we're talking about 6.0's. The Ebay 496 you posted was $2500 - the 6.0L was $1800. You consider $700 to make that much difference that the 496 becomes a "whole different VERY expensive I/O"? $700 doesn't even make it up to the BOAT (Break Out Another Thousand) level. Most people that pay a shop to maintain their boat spend that much having their boat serviced and winterized or having their bellows changed ....

When you start talking "power" in the marine world, anything less than 600-700 HP you're just diddling in the sandbox with the babies in diapers. A 496 isn't even entry level, much less a 6.0L small block. When's the last time you saw a car with twin or triple motors, supercharged and pushing just under 1000 HP each??? In the boating world that's so common it doesn't even draw a second glance. In the "foo-foo" bowrider boat category where you'll find small blocks and 496's, it really doesn't make much difference. You can run in the 60's with a factory stock 496 that will live forever, with off the shelf replacement marine parts, or cobble together a hot-rodded 6.0L that will run about the same speed, with less reliability, for more money.

Looks like GM already offers a marinized VVT 6.0L. If you want to compare engines in equal states of tune, compare the 6.0L output here to the 496 output I posted earlier:

http://www.gm.com/experience/techno...s/specialized/marine/2010_6000_LY6_Marine.pdf

Dollar for hp and tq the 6.0 is the way to go

Dollar for Hp and Tq in a boat (or a heavily loaded truck) the big-block is the way to go.

 

[martin pritchard]

Re: Northstar repower?

whether they mean to or not they are showing a lot of respect for the northstar what with 6/7/8 ltr motors to better it.
i suggest you jump into you car with a trailer on the back go down to the
wreckers get a 4.6 cad make up your own water cooled exhaust i will show you how and save your marriage/house/ family/bank balance/sanity /transom etc

 

[45Auto]

Re: Northstar repower?

i suggest you jump into you car with a trailer on the back go down to the wreckers get a 4.6 cad make up your own water cooled exhaust i will show you how and save your marriage/house/ family/bank balance/sanity /transom etc

See post #12.

 

[fabrimacator21]

Re: Northstar repower?

Very true statement there. A gasoline engine is about 25% efficient. A fuel injected, computer controlled 496 might be at 24.93% while a fuel injected, computer controlled 6.0L is at 24.96%. In other words, you'll never see the difference in the real world. Did the graph I posted a few posts above not show up on your computer???

No it showed up but there wasn't a 6.0 on there..... Also all those engines are in different boats.

The 496 looks like it does pretty well but theres still the matter of the 6.0 burning less fuel in trucks.

No question that UNLOADED the smaller engine will be better. Now hook a 10,000 pound trailer to each of those trucks to simulate the load in a boat and check the mileage. You'll find that they BOTH get 6-8 MPG. Don't be surprised when the 454 gets better loaded MPG than the 350.

My 3000 pound dual-overhead cam Saturn with a 4 cylinder gets 34 MPG around town, 37 MPG on the road. Do you really think it'll get the same thing with the 10,000 pound trailer behind it???

A DOHC four banger is a whole different story.... I think your indulging a little on the towing mileage.... in my experience the 350 trucks got better mileage towing.... not by a whole lot but still.

How many times have you towed a trailer behind your boat? Unless we're talking about a fairly large boat here I think that point is mute.

I belong to a boat site where there's a guy who is the 496 guru. He took a stock 496 (the lower performance 375HP version, not the HO rated at 425 HP), put aftermarket thru-hulls and had the ECM reprogrammed and made over 600HP.

The above proves exactly what????

Believe be,,,, don't believe me.... I don't really care. Theres plenty of hot rod magazines that have found the same sort of gains out of a 6.0.

Do a little research on them....

I don't know why we're talking about 6.0's. The Ebay 496 you posted was $2500 - the 6.0L was $1800. You consider $700 to make that much difference that the 496 becomes a "whole different VERY expensive I/O"? $700 doesn't even make it up to the BOAT (Break Out Another Thousand) level. Most people that pay a shop to maintain their boat spend that much having their boat serviced and winterized or having their bellows changed ....

So because some boaters pay 75 bucks an hour for routine maintence and other things they could do themselves then price doesn't matter? It does for average joes like me...once you factor in how hot a 6.0 can be for the dollar when compared to a stock 496. The 6.0 takes mods VERY well... it makes impressive numbers without breaking a sweat and I'm not talking about big lopey undrivable at low speed cams.

That was a pretty half assed search on my part.... heres a 6.0 with 36k miles on it for 1350...

Chevy Van 35,775 MILES 35,775 A G2182TF $1350 Precision Auto Parts USA-AZ(Phoenix) Request_Quote 1-602-232-5146 1-877-703-3583


If your paying attention you can find em for as low as 900 bucks with under 50k miles on em at your local junkyard.


So theres 1200 bucks (being fairly modest). Anything you put on a bbc is more expensive so after all the accessories are on both motors it would likely be a bigger difference.

Thats headers, l92 heads, and a cam for less then a stock 496. A 6.0 with those mods would easily push 450hp and 470ft lbs. Factor in the 150 or so less pounds that it weighs than the 496(the less weight out back the better and the faster you go), a little better mileage, and more top end.... I'll take a "cobbled together 6.0" anyday. You can have your 496.

When you start talking "power" in the marine world, anything less than 600-700 HP you're just diddling in the sandbox with the babies in diapers. A 496 isn't even entry level, much less a 6.0L small block. When's the last time you saw a car with twin or triple motors, supercharged and pushing just under 1000 HP each??? In the boating world that's so common it doesn't even draw a second glance. In the "foo-foo" bowrider boat category where you'll find small blocks and 496's, it really doesn't make much difference. You can run in the 60's with a factory stock 496 that will live forever, with off the shelf replacement marine parts, or cobble together a hot-rodded 6.0L that will run about the same speed, with less reliability, for more money.

Try less money... thats the whole point I'm trying to make. As far as reliability goes... the 6.0's are brick ****houses....

I'm fully aware of the rediculous amount of power it takes to go fast on the water.... but we're talking pleasure boats so I'm assuming we're staying in that realm.

Dollar for Hp and Tq in a boat (or a heavily loaded truck) the big-block is the way to go.

Big boat... sure...

18-20ft...

I disagree.

 

[mylesm260]

Re: Northstar repower?

Fabricator is absolutely correct.

Furthermore, I think you are totally under estimating the difference in brake specific fuel consumption between a gen 1 and a gen 4.

And the fact of the mater is,

The 6.0 and the 496 have very similar HP numbers, albeit not as much tq down low, but the 6.0 is built way way better.

6 bolt mains with girder.
coil near plug ignition (no more cap + rotor)
a rotating assembly RATED for 6500 rpms...
A much much shorter stroke (for longer ring life)
Much lower ring tension (for less friction and better mileage)
Modern EFI (altho some 496 packages can have this as well)
Modern intake manifold design, for a smoother torque curve.


And, on top of all that, they're a dime a dozen. With the way those engines are built, I would have NO problem taking a used engine with 50,000 miles in it and put it in a boat. It would last 1000 hours, easily, amusing it was well maintained.

 

[martin pritchard]

Re: Northstar repower?



http://i1004.photobucket.com/albums/af170/martin_pritchard/martinspics004.jpg
http://i1004.photobucket.com/albums/af170/martin_pritchard/martinspics003.jpg

check out these photos of northstar powered jet boat

 

[45Auto]

Re: Northstar repower?

All those motors, with the exception of the outboards, have combustion chambers that were basically designed in the 70's.

So how come it took them so long (till 1996) to start using those Vortec heads that you claim were designed in the 70's???

I'll take a "cobbled together 6.0" anyday. You can have your 496.

Thanks! We've been enjoying our 496 in a Crownline 225 for about two and a half years now. How long have you been running a 6.0L?

Big boat... sure...

18-20ft...

I disagree.

Looks like we're talking about different things. I was directing my posts more towards the mid-20' range: 22' and up. 20' or less, I agree, a small block would definitely be appropriate.

(6.0L) It would last 1000 hours, easily

I would hope so. The 496 below that sold on Ebay last month was still running (but smoking from one cylinder) with 2500 hours on it. I'm averaging 80 hours/year on mine, counting on it to last about another 25 years ......

 

[45Auto]

Re: Northstar repower?

Found these tests looking for something with a new marine 6.0L in it. Only thing that I could find was a big express cruiser with twins. They had a couple of similar sized 496's to compare them to. Also had one with twin 5.7L small blocks.

Four Winns V358 - Twin 6.0L 375HP - 14,800 lb
http://www.boattest.com/boats/Boat_video.aspx?ID=990#Test-Result

Formula 34 PC - Twin 496 375HP - 15,710 lb
http://www.boattest.com/boats/Boat_video.aspx?ID=2000#Test-Result

Formula 350 Sun Sport - Twin 496 425HP - 12,950 lb
http://www.boattest.com/boats/Boat_video.aspx?ID=1649#Test-Result

Bayliner 340 - Twin 5.7L - 300HP - 12,660 lb
http://www.boattest.com/boats/Boat_video.aspx?ID=1695#Test-Result

Once everything comes on plane at around 17 MPH they're pretty even up through the mid 20's. Then you can see an obvious difference where the efficiency of the two lighter boats keeps rising while the two heavier boats are falling.

In the lighter boats, the twin 350's are slightly more efficient but about 15 MPH slower than the 496's.

In the heavier boats, the twin 6.0L's are slightly more efficient but about 10 MPH slower than the 496's.

Once you get above about 25 MPH the efficiency falls in line with the boat weight, lightest on top to heaviest on bottom. When the smaller engines in each group start running out of power about 37 MPH, the larger engines become more efficient and also keep delivering more speed.

Doesn't appear to be anything exceptional either way about the 6.0L performance.

 

[fabrimacator21]

Re: Northstar repower?

Doesn't appear to be anything exceptional either way about the 6.0L performance.

Those are HUGE boats.

Stock for stock thats a given when compared to a big block.... I was talking about a hot 6.0 compared to a stock 496. If both of those 6.0's had the heads, cam, and headers that you could buy from the price difference the test would look alot different.

I'm impressed that you could find those charts though.... although it's hard to make a judgement when they are in different boats with different weights and different hull designs.

 

[fabrimacator21]

Re: Northstar repower?

Thanks! We've been enjoying our 496 in a Crownline 225 for about two and a half years now. How long have you been running a 6.0L?

It'd crunch my I/O in 5 seconds flat.... but one will be going in my 1988 k5

Looks like we're talking about different things. I was directing my posts more towards the mid-20' range: 22' and up. 20' or less, I agree, a small block would definitely be appropriate.

I figured we were.

 

[justchange]

Re: Northstar repower?

I sure did start a large disagreement with most everyone. Shows how different outlooks we all have. This is a good thing.

Actually, my plan has changed as has my income. Not due to the economy, but my health. So, odds are this project won't be done. At least by me.

Am exploring other options and want to thank everyone for thier input.

 

[scipper77]

Re: Northstar repower?

I am very sorry to hear that you are having health problems!! I think you will find that when the guys on this forum are done bashing you on your motor preferences, we really do care about the members of our I-boats community. (even 45auto lol)

 

[45Auto]

Re: Northstar repower?

Hey, somebody has to add a little excitement to this place every once in a while! You wouldn't believe how hard it is to keep one of these threads going for over 100 posts!

 

[justchange]

Re: Northstar repower?

Thank you both for that. I am amazed that it's gone this long and yes, I did notice the concern about others.

 

[zbnutcase]

Re: Northstar repower?

Will this thread ever die?? 'nutcase

 

[fabrimacator21]

Re: Northstar repower?

I'm not exactly sure how the variable valve timing works but if it works like I think it should with 4 small valves and only one intake and one exhaust working until higher RPM's, it's the perfect way to build low end torque. Seems to me it would have an extremely flat torque curve which is what you want in a marine engine.

That isn't how the variable valve timing engines work and theres only 2 valves per cylinder.

They electronically advance/retard the cam using an electric solenoind.

Some of the foreign makers are working on cams with the lobes cut on an angle. Then they would just have to move the cam forward or backwards to advance/retard.

They're even talking about putting soleniods on each valve in the future but I'd have a hard time trusting it.