Turbo vs Supercharger
02-21-2012 | 08:24 PM
#61
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From: Florence, Kentucky
Ok, if the modern DOHC is marinized and we saw a movement to this style would it not overcome the ethanol issue? Ie, running E85 in the motors? Granted everyone would need 30% larger fuel tanks but hey, would do wonders for FI applications.
02-21-2012 | 09:24 PM
#62
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From: Allen Park, MI
Jeff - I agree with your logic and facts but the comment was "Hp for nothing" which it isn't. I do agree with the scoop thing but not so much on the Whipples, the big roots type with the intercoolers are so tall and adding those big scoops just takes away from the look. Belts, again the big roots type blowers with one idler, don't know more don't come off?
As far as the first guy doing gas engine turbo's in offshore boats, didn't Merc way long ago have some turbocharged race engines before Gentry, I seem to recall that but could be wrong? If you look at the old ABPA rules (1980's) for open class there was always math for penalties for turbo engines - someone had to have them?
As far as the first guy doing gas engine turbo's in offshore boats, didn't Merc way long ago have some turbocharged race engines before Gentry, I seem to recall that but could be wrong? If you look at the old ABPA rules (1980's) for open class there was always math for penalties for turbo engines - someone had to have them?
02-22-2012 | 12:00 AM
#63
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From: San Diego, California
CrownLPX in answer to your question about ethanol in DOHC engines in marien use the answer is NO! please study the rpoblems and issues with E85 ethanl and you will see the problem is not solved or cured with an engine valve actuation change.
As for Mercury Racings develoment of a DOHC marine engine it was pretty much to get away from one of the most difficult problems to solve on endurance BBC marine high performance engines -valve train stability on larger cubic inch higher horsepower versions at higher operating rpms.
Mercury already had a lot of somewhat publically unknown expierence with this type of engine with the LT5 DOHC engine they cast and hepled develop and assemble for GM starting back in the late 80's.
If you are going to develop a new DOHC big block engine it isn't engineering wise efficient, practicle or reasonable to do it on the standard GM type OHV pushrod block PERIOD!
Don't try, start with a c;ean sheet of paper!
As for turbos, I think the driving force here was to create bigger power in a smaller tighter package that would have some reasonable intervals between refreshening and rebuild and could re-establish Mercury Racing as the premier big power, high tech marine racing engine builder. Kinda think that they accomplished all their action points right on the money. By the way with a lot of money for a product that costs a lot of money! They did however at the same time raise the bar to a very high level!
JMO
Best Regards,
Ray @ Raylar
As for Mercury Racings develoment of a DOHC marine engine it was pretty much to get away from one of the most difficult problems to solve on endurance BBC marine high performance engines -valve train stability on larger cubic inch higher horsepower versions at higher operating rpms.
Mercury already had a lot of somewhat publically unknown expierence with this type of engine with the LT5 DOHC engine they cast and hepled develop and assemble for GM starting back in the late 80's.
If you are going to develop a new DOHC big block engine it isn't engineering wise efficient, practicle or reasonable to do it on the standard GM type OHV pushrod block PERIOD!
Don't try, start with a c;ean sheet of paper!
As for turbos, I think the driving force here was to create bigger power in a smaller tighter package that would have some reasonable intervals between refreshening and rebuild and could re-establish Mercury Racing as the premier big power, high tech marine racing engine builder. Kinda think that they accomplished all their action points right on the money. By the way with a lot of money for a product that costs a lot of money! They did however at the same time raise the bar to a very high level!
JMO
Best Regards,
Ray @ Raylar
03-22-2012 | 11:36 AM
#64
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From: Turku, Finland
Merc had them back in the late 70's early 80's. Here's a couple pics of my 1980 38 flatdeck Scarab that i sold a while back. I loved those engines. I could cruise all day and stay out of the turbos (under 4 grand) but when I needed them they were there. Put you back in your seat. Merc 454s 12lbs boost.
Last edited by MikeyFIN; 03-22-2012 at 11:47 AM.
03-22-2012 | 11:37 AM
#65
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From: Turku, Finland
Daytona marine produced some turbo motors back in the late sixtes on 427 truck engines with a single carb blow through and one inter cooler. And i think they also did a 482 engine. When i am ready i will do a twin turbo setup hands down m
ore power than anything else out there.
ore power than anything else out there.That was in the British Surfury Raceboat at the time which won practically everything.
That boat had so much pulling power that it's avarage race winning speed 45 yrs ago at CTC even puts Apaches that has raced the same race even to shame...
03-22-2012 | 12:00 PM
#66
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From: Turku, Finland
The overhead cam issue would have been settled years back, Ford had their cammer that they wanted to run on the NASCAR tracks, so Chrysler got wind of it and put a prototype DOHC Hemi (big time HP and RPM Potential) together, that Engine shocked Ole France when he saw it and he Hated Chrysler BTW, Bill swore they would never run those Motors in his racing, so we still see the 30 year old technology running there.
Now If Ford and Chrysler would have raced these, then GM would have stepped up or been left running last and this would be the norm today, But that ONE lunk-head put the kibosh on racing technology.. LMAO Chrysler called it the Doomsday Machine.
Now If Ford and Chrysler would have raced these, then GM would have stepped up or been left running last and this would be the norm today, But that ONE lunk-head put the kibosh on racing technology.. LMAO Chrysler called it the Doomsday Machine.
03-22-2012 | 01:20 PM
#67
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From: Turku, Finland
Now on a serious note.
In a pushrod engine especially a 2v there's one advantage and that's low bottom torque, therefore in a marine engine slap a Turbo keep the RPM's under 5000 and use high boost and even nowadays with the ignition controls we have you could run a sequential mechanical fuel injection even, ( a diesel pump basically), just saying.
But the days of the Gasoline engines are numbered.. .even though the Soviets fell in their own nuisance (general lazyness) one thing is for sure Russians sure as hell still can build big power and high tech diesels....with Turbos and superchargers in the same package
Here's one I have fell in love with lately: Zvezda M504:
56cyl. Turbo¢rifugallly charged, multivalve and aftercooled radial engine at 11680 c.i. and 5000 h.p @2000rpm constant rating (read nonstop ) Tops has been in a "boat" close to 8000 at classified r.p.m. These were the mothers the Ruskies targeted to level the whole world with in bombers some 70yrs ago... so much for "Modern DOHCs"
Last edited by MikeyFIN; 03-22-2012 at 01:25 PM.
03-22-2012 | 08:50 PM
#69
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From: Michigan
