Here is a question for you "Hot Rodders"...can a 4.3 V6 be built to put out close to 300 hp at 4000 rpm? With the 1.71 PSRU I can't go over this limit with the 88" prop.
Thank you! I cannot open this file...can you send it in a PDF?You may expect 240hp@4000rpm for a normal aspirated 4-stroke 4.3 V6 if you if take your engine to an experienced engine engineer.
This spreadsheet comes in handy...
Up until now the spreadsheet has shown 'real world' figures.
I know people get an idea and want to stick with it, but look at it this way. An LS?Thanks! I ran numbers from 298 hp @ 4000 rpm to 258 hp @ 4000 rpm. We may bore & stroke this engine to 287 ci. This would be 3/4's of Chevy's famous 383 engine. The 4.3 V6 is a SBC minus two cylinders.
That's the easiest part - plug and play:.... Ignition system may take a little work......crank trigger maybe...
Yes, you are correct. But the problem is weight & overall dimensions. Our V6 is all aluminum, so it is lightweight. Plus we have a very well engineered and tested PSRU drive system that is lightweight as well. This V6 with the stroker kit will easily put out 300 hp @ 4,500 rpm. And it will loaf along at 2400 rpm cruise which is where the torque numbers are real good.I know people get an idea and want to stick with it, but look at it this way. An LS?
V8 Chevy will weigh about the same as a cast iron 4.3 (262 cu in) V6.
You will have to stress the V6 with higher rpms while a 415 cu in LS3 would basically
loaf along and easily produce 300 hp way below 4000 rpms.
You can purchase aluminum heads for the LS dirt cheap while aluminum heads for the 4.3 will cost you more than the basic engine. Personally I plan to use some LS1
heads which should keep the air flow plenty fast (2700 rpms in my case). You can purchase 2 used LS1 heads for $100-$150 on ebay easily. This will also allow the use of the cheap and easy to find LS1 intake manifold if you inject it. I don't recommend the LS1 block because of thin cyl walls that don't allow much reboring.
You might even be able to produce the 300hp at a lower engine rpm and slow prop speed even further.
There is a shop on Ebay selling 415 stroker 8.5 to 1 compression ratio forged crank and pistons professionally machined and assembled short blocks for about $4200.
Bolt the LS1 heads on with a factory GM parts intake and carburetor. Ignition system may take a little work......crank trigger maybe.
The point is that you have a far more efficient engine design that is all aluminum and very strong, and it doesn't have to work hard to get the power. If you read anything about these engines you will see that power is rediculously easy to extract from them with just a few mods. Price for building and stroking an alum head V6 will be comparable and you will have a lot more harmonics to consider with the V6.
Also, GM changed the firing order from the old 18436572 of the small block Chevy so that the engine produces less harmonics from the firing order.
xxxxxxYes, you are correct. But the problem is weight & overall dimensions. Our V6 is all aluminum, so it is lightweight. Plus we have a very well engineered and tested PSRU drive system that is lightweight as well. This V6 with the stroker kit will easily put out 300 hp @ 4,500 rpm. And it will loaf along at 2400 rpm cruise which is where the torque numbers are real good.
If you already have an all aluminum V6 and a PSRU then I assume you are locked in to using that combination. I mean these as objective comments so please take them in that context. First, a PSRU that will survive 300 hp will probably weigh about 80+ pounds which coupled with an aluminum V6 will be comparable to an LS V8 with a direct drive bolted to it. Lengthwise the V8 should be slightly longer but it depends on the driect drive length and the PSRU length. I had a Geschwender PSRU and it was over 80 lbs without any oil or attachment bolts.
The V6 crankshaft design is not as strong as a V8 because of design compromises to make it work. Special balance shafts were incorporated to compensate for vibrations caused by the odd balance/firing order.So, resonance may be a problem.....maybe not. Since you are running a stroker, maybe your crank is designed differently from an OEM ???
I'm a little confused as to your RPM calculations.At 4500rpms/300+hp I assume your prop will be turning 2700 rpms. I don't have time to calculate tip speed cause it quitting time. If the above conclusion is correct, then at an engine speed of 2400 which is slightly morethan half of 4500 your prop would only be turning slightly more than half of 2700 rpms .....say 1500 rpms. If you mean that the prop will be turning 2400 rpms,then your engine would be at 4080 rpms. So maybe I'm misunderstanding what you meant. The upside of the PSRU is making thrust line location easier if its
a high wing application. If its a low wing, it may raise it too high. How about a little more specifics on what you are building and what you want to accomplish? It sounds like an interesting project, so I hope your ideas do work for you.
As much as I would like to drop in a GM crate 350, it just will not work without major engineering issues being solved.
. Shush! Torq is a four letter word around here.:gig:As the engine of choice for the T-51D Mustang is now the LS3 6.2 V8, it will easily make 300hp at 4,000 rpm. And normally aspirated. Note that it makes 400 lbs of torque at the setting also.
Of course, this is a sea level number.