Advice on camshaft choice for my sbc......

I'm a pragmatist, in the strictest sense, an engines job is to convert fuel to power. I would define efficiency by BSFC numbers. I've never dynoed a Prius, but the pro stocker vs Prius comparision would be interesting...

 

So sounds like the Atkinson cycle Prius engine would be the winner or of course Diesels like the Audi 2.5 TDI if you can live with an oil burner.

In competition engines the rules dictate the most critical efficiency. For our engines to power our hobbies it's SPG, smiles per gallon. And sometimes to get those smiles we prefer a less than optimum combustion engine to give us the sound or feel we want.

Personally I am closely aligned to your belief, but I understand that my beliefs are not widely held

 

Cool find, where did you scrounge that up? Re: the diesel thing, for my money, you cant really compare BSFC numbers for engines on differing fuels, you are comparing the inherent characteristics of the fuels as much or more than the relative efficiency of the engines in question. Same thing goes for N/A and forced induction, its just not a fair comparision.

 

By the way, the numbers for the old Wright-Cyclone in that table are quite a surprise! Cool stuff.

 

The purpose of the Turbo-Compound was to allow more expansion of the exhaust to be used as work. They geared exhaust turbines to the crankshaft.

The complexity was ridiculous, and mechanics referred to the PRT's as Parts Recovery Turbine.

BTW, gasoline is slightly more energy dense as far as weight goes, 46.4 vs 46.2 Mj/Kg. You would need to multiply Gasoline BSFC by 0.995689655 to make it energy equal, I'd say that's nit pickin'

Of course Diesel has more energy per gallon but that's not what BSFC lb/hp/hr is about, that would show up in G/HP/Hr. Of course the efficiency number cancels all that.

 

Yea, but you squeeze the diesel alot harder. For my money, theres just too many variables to compare differing fuels like that. And we are wandering a looong ways off the topic now...

 

Diesels have 2 large advantages;

1. Unthrottled so do much less pumping work at part throttle.
2. Big squeeze means big expansion and Expansion is the key!

 

That's kind of what I was getting at- a comparison that allows for dissimilar engine types, fuel types, sizes, cylinders, forced induction.
It's either more efficient or its not.

 

Well, we are comparing the two in terms of BSFC, when you start comparing across different fuels based on BSFC, its a LOT more complex than that, and IMO, just comparing a gas engine to a diesel in terms of BSFC can be misleading.

 

Yes there needs to be a conversion factor and then if you want on that particular day a price factor too.

 

#2 in spades, and this links us back to the original thread, and the conversation that I dont really want to have on a public forum like the HAMB, re: wide LSA/high mech. compression high perf street motors.

 

GODDAMMIT!! For someone who promised himself no more HAMB cam/carb threads, HOW did I get drawn so deep in to this??!!

 

Lol I don't know and I do apologise lol, well I've chosen my cam got it coming down next week so be rebuilding engine next weekend.....


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I think an extra decimal may have slipped in there.
100,000 lbs = 50 tons
50 tons X 100 miles = 5000 ton*miles/gallon

CSX train sites toss around numbers like 450-480 ton*miles per gallon

My old 3400 lb 1.7 ton Volvo gets a little over 20 mpg.
That's about 40 ton*miles / gallon

 

Hmm, maybe I got it wrong. It was in a article about the new GE Evolution train. It was an impressive MPG # (or however they rate it). BTW, I get around 45 MPG in my VW 1.9 TDI. I'd like to build an M-TDI with a Toyota 5 speed & drop it into one of those Speedway Track-T kits

http://www.getransportation.com/rail/rail-products/locomotives/evolutionr-series-locomotive.html

Sorry about the o/t hijack

 

You're like a moth to the flame FG!


The right hand column in that chart is the raw energy efficiency, no weight or volume involved, energy in (Joules) /work out Joules

 

Is the Audi N/A? I honestly dont know much about them...

 

Did you see the thread killing youtube video of the hot rodded Evinrude 2 stroke V-8 I posted on the "best sounding engines" thread? SCREW the gas mileage, I want to build a track T around one of THOSE!! Or better yet, put one in a Lotus Super 7...

 

The TDI's are TurboDiesels. They mostly (Except Audi/VW and a few) went away for a long time due to the US's stringent Diesel Emissions. Now that Europe is catching up in Emissions we are starting to see more of them. Dodge/Ram is introducing one in it's LD pickup. A diesel is about the same efficiency as a Prius type Hybrid at a much lower cost.

At some point our kids will be rodding our current cars with all kinds of powerplants, because that's what rodding is The 70s and 80s cars are perfect future Rods, because their power plants suck so bad.

I wonder what they will call their Message Board

 

No but i would like to ,My 60hp 3 cyl Evinrude sounds wicked out of the water( while trying to tune them 3 dam carbs )8 should sound bad ass

 

The 268 I used was high energy.

 

Hi, thanks that's the kiddy I ordered Friday cheers Jason.


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