Hi Smitty,

I'm gettin old man.... Transposing things.. Yessir, the engine A will use the 50% less and engine B 50% more.. (61-41)/41 is about 50%.. Thanks for catching it and letting me know... This typing thing is just not my cup of tea...!

Oh, Running the mixture richer with a blower to keep the piston cooled should be addressed with proper intercooling, proper oiling, head deburring, piston crown coating, squish, chamber shape, head flow, flame front and spread optimization, injector spray pattern and a few other little bits of art including less fuel rail pressure....! But, my guess is that you know that as well as I do too. LOL..!

Hey, Some guys tuning some NA V8 motors out here get a .41 BSFC with 6.5L and 650HP... Not a Chevy, but it can be done with similar attention to detail..

Lean is mean, and that is another reason I got into researching the Thermodynamic issues as much... The heat management is critical.. Too much fueling to cool the piston is going to take too much heat out of the chamber, and that also affects BSFC... You need the heat in the chamber to get all the mixture burnt and a complete burn also increases power, uses less fuel than an incomplete burn, reduces emmissions, and promotes cooler EGT's as well..

Let's not forget that 2.0L BMW F1 turbocharged motors made over 1000HP in the 70's.. They will never tell the BSFC of those engines to me, but I think I would be happy with 120-150HP per Liter of displacement at a BSFC of .45 in a low pressure positive displacement environment.. Can I achieve that, don't know.... If the budget was unlimited, and I could sponsor an F1 team.. Sure...

R

Well, we're gettin close..

Haxby,

Very good show..! Try to hit the 100 HP per Liter mark with those BSFC numbers...! With a 434CI motor you should be more than 700 HP..! at that BSFC, the fuel burn rate will be stellar..!

The 6.5 L I spoke of is at the 100HP/L mark. However, it runs fuel injection. I think with a Carb it will be more difficult than with EFI, as the air/fuel mixing is linear, where as with EFI, you can have compound function programming to have more control as a function of load.

Keep it up..!

R

Are you going to run a system with constant O-2 sensors to keep that engine at the optimal fuel burn the whole time?

I am not engine builder but I think that is going to be tough with a centrifugal blower and expecially a small one at that. Things start getting kind of funny as hp creeps up. Like Smitty and Kenny said, things start to defy physics. In order to get fuel to flow at higher hp, you need bigger injectors etc. Some of these things are not happy duned to lower hp. The other problem is that flow requirements are not necessarily linear. Nor is boost on a centrifugal blower. They also don't move in a parallel fashion. At lower boost levels an engine that is capable of flowing well may get starved out by a smaller blower. You would have to have one hell of a precise tune. Then you get into different loading conditions. It will get pretty hard to tune for all of those variables while bouncing around in a boat at high speed.

I think that you have some cool ideas at work but this will be one heck of a project.

Couldn't leave it alone could you.....

What, me leave something along?

Nah, I am just glad that someone else is joining in the frustration of wrestling with a centrifugal blown motor!

I figured that after watching Eddie have more than a little fun getting mine straightened out on the dyno that I am almost an engine builder myself now....not!

Working on a collection of blower pulleys that resembles the one you amassed a couple of years ago.

Went down from the stock 4.75 to 4.00 inches and almost nothing happened. Went down to 3.85 and it all happened. The whole pulley size combo/boost and how much flow does an engine need is not a linear thing. I did not expect it to be, but wow!

I got your pm, thanks. I will try to give you a shout later.

I hope you invested in 12 rib for the 3.85 stuff,I got inconsitent boost unless belt was rubber band tight until I went from 8 rib drive to 12 rib drive. Just think how hard it is to get your blower to make power increasing boost,maybe you should have got a m-1 instead and spun it 75,000 rpm's. . Smitty

No, I can see a 12 rib possibly on the way. I have a 7.5" lower pulley.

The M-1 is on order. I will get the non-SC version and spin it to 80k.