Upping the HP on a 6/1

[GuyFawkes]

i certainly was not suggesting that the use of tuned runners in the intake and exhaust is going to make the engine
markedly more efficient, that was not my intent.  simply a reply on how to get a bit more power, which you will by getting more air in(increasing vol. eff.) and(reducing pumping losses) but at the expence of adding more fuel.

if a 6/1 burns approx 250 grams/kwatt/hr, then even with these mods an 8/1 is likely going to burn approx 250grams/kwatt/hr.

the question was one of increasing hp, not economy.

i dont think many of us can effect economy to any great extent over the original design.

what is interesting to note, is the apparent similarity of consumption rates based on size of engine.
the cox .049 glow plug engine is very close to the same efficiency as huge ocean going diesel engines.

ok, more power for more fuel, doable

the efficiency you mention is simple, you are measuring BHP, measure torque and you'll see the differences in engines

bhp is bullshit, a litre of fuel an hour is a far better metric.

[mobile_bob]

i used hp in only a generic term

hp is basically a misnomer in my books also.

i used it as a catch all to cover in shorter terms  " grams fuel consumed per kwatt hour generated per hour" or "grams/kwatt/hr"

hp is such a joke anymore, maybe it always has been.
for instance
cat now markets a C7 engine that is being used in heavy trucks, it is reported to be 330 hp.
at 7 liters the little engine can't pull an 80,000 lb load at half the road speed of a 3406 cat(approx 14 liter) at the same rated hp.

perhaps the whole discussion should be reworded to be "how can i get my 6/1 lister that produces 3.5 kwatt/hr to make 4.2 kwatt/hr generated?"

actually that might be a better discussion that could be measured by most folks trying to up the output. At least then one could observe a measureable gain using common instuments.

or something like that, follow?

bob g

[cujet]

Guy, I think you are wrong on the tuned intake/exhaust issue. However, I am not sure, as I have no such data on Listeroids. 

But if I remember correctly, the VE of a listeroid is about 75%. That means there is potential to reach 100% VE with tuned runners.

If you remember correctly, most automotive applications of tuned runners are 4th order. In other words, even more power could be had with runners 2 or 4 times as long as what is currently used.

While it could be absurd in length, a listeroid application specific tuned intake and exhaust would probably enable 100+ VE.

This could result in a substantial power gain.

Chris

[fattywagonman]

I just got a chance to get caught up on this discussion...  Happy POP's day to all the fathers out there.. I thought about adding my .02 cents bout' scoolin' but I tend to agree with most of what's already been said... Bazck to engines.. I agree with guy and bob and think gaining anything more than a few percent of efficiency requires a different design... combined cycle or recuperation / regeneration are possibilities.. The lister is efficient for a couple of reasons.. the engine turns slow so pumping losses are minimal... and the cylinder is large so heat absorbtion is less than with a smaller cylinder... If you want more power IMO that's easy... the engine is a pump... and the faster it turns the more it pumps... double the RPM to 1300 and 12 HP is possible from the same bore and stroke..  pumping losses are still low at 1300 but the crank and flywheels won't take it.. so far the GM 90 design is the best thing I"ve seen for higher RPM's .. counter weights are much better on the crank than the flywheels.. I also have a design for a 2 crank and 2 flywheel single cylinder engine that would be vibration free...another  other option is to keep the RPM's low and add more air / fuel proportionatly... no real sacrifice of efficiency but if you double the inlet pressure I would expect less than half the engine life... even a 3-4 PSI increase would produce some good results... finally why not just increase the bore ... if you do this efficiency is increased and so is the power ..  I think larger cylinder / piston can be obtained from india for less than $300..  the bottom line..IMO  there's no replacement for displacement..         

[fattywagonman]

Chris,
Because of the low RPM I bet the VE is more efficient that 75%... I'll bet it's close to 90%.. no data to back this up.. it's just a hunch...

[kyradawg]

Peace&Love , Darren

[fattywagonman]

Darren,
Not sure what you ae proposing... I thought we were talking volumetric efficiency.. not thermal efficiency... thermal efficiency is the engines ability to use the heat from combustion.. TE is usually effected by the size of the bore and the comp ratio..   I don't think porting is going to do much for TE.. maybe a little for VE but since this is low RPM my gut says not much..  a proper designed turbo can offer some TE improvements.. (since there is usually some temp drop as the exhaust moves through the turbo).. but the gains are slight at best.. at best  engough gain to drive the oil pump for the turbo..   

[fattywagonman]

This engine has a TE of 50%
http://www.bath.ac.uk/~ccsshb/12cyl/
I believe this is the highest ever TE attained in an IC engine.. It is atributed (for the most part) to the large bore and long stroke...

[kyradawg]

Peace&Love , Darren

[fattywagonman]

I forgot to mention the uniflow design..

[fattywagonman]

Darren,
IMO you're not going to chance the TE very much... it is mostly dictated by the design and the size of the bore and stroke of the engine.. as for the VE that is the # that measures how well the engine uses it's displacement... if you can get all the air in so you have a full 14.7 PSI in the cylinder at the bottom of the intake stroke then you have 100% but that's never the case.. as mentioned I"ve played a bit with the miller atkinson cycle which reduces the displacement but improves the TE a bit since less work goes into the comp stroke and retains the long expansion stroke..   

[kyradawg]

Peace&Love , Darren

[fattywagonman]

Any time you create more complete combustion more of the thermal energy of the fuel is being converted in to energy.

Yes I agree.. but honestly most combustion is usually pretty complete.. even a poor injection system burns 95% or more of the fuel injected... anything less and you will have a lot of smoke..

[kyradawg]

Peace&Love , Darren

[kyradawg]

Peace&Love, Darren