4.3 litre turbo?

[1973 Browning Marine]

There is a version of the 4.3 liter v-6 automobile engine with a turbo charger. I think they were installed in The Typhoon/Cyclone. Has anyone been able to do this with a marine version of this particular v-6? I think I remember reading that the turbo version makes up to 280 horsepower which would be within the constraints of an alpha one drive. I also understand that the 4.3 liter would have to be of marine specs. and not an automobile version. Also, is there a big difference in the auto cam and marine cam in the 4.3s? I know there are also different pistons and freeze plugs (brass) and gaskets for marine applications etc.,etc. Buick also made one hell of a turbo v-6 in the Grand Nationals but it puts out way to much horsepower for the Alpha One. What do you guys think about the 4.3 turbo version in an 18 foot boat? (And is it possible?) Just dreamin, Tom

 

[bondo]

What do you guys think about the 4.3 turbo version in an 18 foot boat? (And is it possible?)

Ayuh,... It would be Thousands of Dollars Cheaper to just drop in a 350...

I hear water cooled turbos are rather Expensive....

 

[1973 Browning Marine]

I guess you are right Bondo, I was thinkin the same thing but was trying to avoid the v-8s because of fuel consumption,weight, and basically the price of fuel. I was kind of wondering if it could even be done? I guess anything is possible if you have wheelbarrels full of money! (wish I did)lol thanks for the advice, Tom

 

[o2batsea]

I guess you are right Bondo, I was thinkin the same thing but was trying to avoid the v-8s because of fuel consumption,weight, and basically the price of fuel. I was kind of wondering if it could even be done? I guess anything is possible if you have wheelbarrels full of money! (wish I did)lol thanks for the advice, Tom

Hey this is boating! You gotta get your priorities straight. Saving money is somewhere near the bottom of the list. Uh, turbo is fine, in fact if you can find one off an old Cat or Detroit diesel marine engine that has the water cooling you're in luck. Supercharging is probably a better way to go since it can be done "dry". Thousands of ways to skin the cat, let us know how it works out.

 

[hystat]

avoid the v-8s because of fuel consumption,weight, and basically the price of fuel.

the whole objective of a turbo is to put more air in the engine...why? so you can put more fuel in....

there is no free lunch

260HP from a tubo V6, or 260HP from a 350 V8 = same fuel quantity

the only way to save fuel is to go slower and any 4.3 is capable of that

 

[04fxdwgi]

Often pondered about that myself, but decided against it pretty quick. Have had several "turbo" vehicles and heat emitted from those things is intense. On a gasoline powered engine, the exhaust manifolds and pipes between the heads of a V6 or V8 engine configuration and turbo inlet needs to be dry and kept as hot as possible, as a decrease in manifold temp relates to a decrease in turbo efficiency. The turbo needs the exhaust velocity to remain as high as possible to spool up, as can be heard when a turbo powered car is accellerating, turbo whine increases with an increase with exhaust gas flow. Cool it and the velocity slows due to the exhaust gasses are becoming more condensed as they cool, losing the velocity. Cool exhaust to an acceptable level for the enclosed engine compartment of the boat and the turbo would be rendered basically ineffective. If engine is not enclosed, then you could do it, but who wants an open engine compartment in the boat. Now, a supercharger (blower), on the other hand, is a whole different animal and does not rely on the hot exhaust to do anything to make it work. That's why you see superchargers in gas powered boats and not turbo's. Diesels are usually in much larger engine compartments and of course, the diesel fuel does not present the hazards of gasoline, so the turbo equipped diesel is not a good comparrison model. Apples vs: Oranges.

 

[hystat]

a decrease in manifold temp relates to a decrease in turbo efficiency. .... Cool it and the velocity slows due to the exhaust gasses are becoming more condensed as they cool, losing the velocity.

I'm no engineer, so I couldn't really follow that but cooling a turbo has no effect on power in my experience. seen lots of turbo diesels in boats and every single one had a water cooled turbo.

Some automotive turbos are water cooled - heavy equipment too... just keeps it from starting fires.

 

[04fxdwgi]

The "turbo" itself isn't water cooled, the center bearing section is. You need to keep the exhaust (hot) side of the turbo as hot as possible to maintain the velocity going thru the turbine and nozzle section and the compressor side discharge usually runs through an intercooler to cool the compressed air as much as possible, creating a more dense air charge, effectively increasing compression in the cylinders. Normally a thermal blanket is wrapped around the turbo to keep the heat contained and the intercooler can either use air as a cooling medium, or in the case of a marine diesel engine, water cooled.

 

[1973 Browning Marine]

Wow, never thought I would get so much of a response! (You guys are great!) You gotta admit, it was a neat idea. The only reason I wanted to use the 4.3 as a rebuild platform candidate was because not much would have to be changed except for exaust manifolds to a y type. Also, would have to probably fabricate new motor mounts into stringers somehow. Thanks for all the info. guys! Appreciate it! This was going to be a long term dealie to replace the infamous 470 that I had just rebuilt. Just want to have another backup and am not even sure at this point what it would be as of yet. Just trying to stir up alternative power plants under 300 horse and a little lighter than a 350 v-8. My transom cutout is set up for the Alpha One and was hoping to stay with that after all the work I just went through getting it working. Question: Has anyone supercharged a 4.3 engine or know anyone who has and what kind of power is attained from doing so? Don-t forget, I would like to stay at a max of 300 horsepower. Thanks everyone for the good information. I just wasn't sure where a 4.3 liter would end up after supercharging if even possible.

 

[04fxdwgi]

Don't forget, if you supercharge any engine, it would be wise to beef up the bottom end of the engine and keep your compression ratio below 8.5:1 (as would be case for Turbo, also). Superchargers have a trait of putting alot of stress on the pistons, rods and crankshaft. Also, ignition needs to be top notch. One hiccup from ignition and a pop back (like through a carb) and it could be catastrauphic to the "blower".

Here is a company that makes a kit for the GM 4.3 Vortec www.wynjammer.com for about 2 1/2 K. There are a host of others, but you get the idea.