gemellocattivo.com

OK, something that has been scratching around in the back of my head. Dyno results and power claims. I've spent a fair amount of time on a dyno and can state that anyone can make a dyno spit out any number one would like. I've also spent far far more time then I really wanted getting into the nitty gritty of engine dynamics as it relates to the combustion process and ultimately the power developed.

That said I find that there are claims of 'X' power out of engine builds that are patently impossible. The amount of 'fluffing' needed to make the claim possible would put a porn shoot to shame
Take the CIS fuel intake system, the choke point and layout alone not to mention the area of the filter is a massive restriction on the air flow into the engine, coupled with very poor manifold layout there is no way any engine could breath enough air to support 300Hp. I don't care how big you make the bottom end, matter of fact the bigger the valves, bore etc.. the higher the risk is for sonic choke or stall.

I'm going to sit down over the next couple weeks and flesh out an article/paper on this, I've been asked to write up about it and figured why not? I know it's going to cause arguments and get some worked up but that's what gets people to read right? I just need to figure out how technical to make it, 'white paper', 'scientific journal' or 'laymen'

Scott, I'd vote for a format that most hotrodders can understand.

I've forgotten all the calculus and differential equations I once claimed to know, so whenever I see integrals or partial differentials nowadays, I turn off completely and go read something else

OK, Sounds reasonable. I'll more then likely add references then with the more advanced info for those who may want to delve deeper. It's tough though, a cursory overview runs the risk of being viewed as opinion which opens the possibility of having to defend it by either pointing to said reference or finding a way to educate many on the details that make it so. There is a recent thread over on the speedtalk site that touched on this a bit, in that someone wanted to know where all the good 'secrets' are for making power etc.. and while no-ones going to take the time to publish hard earned info nor is there any time to do so for race teams, the bigger issue is that real information does already exist, it can be found in patents or textbooks that are in all honesty beyond the educational background of a majority of people. Reducing it down to simple terms is possible I suppose but the precludes that the audience has the educational background to refer to or we end up with miss information and miss application of information.

That leaves me wondering if a longer article that explains it with more simplistic terms would be favorable. It would be a much longer article but it would be written so as to be more understandable without having to read thru a mathematics paper. Would that be preferred?

I'm sitting here suddenly thinking about the flame kernal and flame front propagation and Prof Blairs work and how to make that more understandable ... thermodynamics done easy... right?

Wait I got it... I'll do it all in memes!

Well, I never claimed huge numbers when I did my motor. Here's a snapshot of what mine did.
I was hoping for a number close to 230-250hp.
The dyno guy had told me that I was max out on any more air getting into the motor. She still needs a little more adjustment but I'm happy with her now.

Here's a video for entertainment purposes only.

http://www.youtube.com/watch?v=WWBOFCAJKGg

Chris, that's a very strong and flat tq range, makes for a great daily driver. Good job!

Don't worry I'm not talking about anybody here or even on the other F site. Mostly this is in reference to other professional builders, what I find interesting is that there are these BIG claims for power yet other then the Co's claim there is nothing else. I know marketing hype, but I don't think people really understand just how next to impossible it is to squeeze 300+HP out of the tiny 3x8 engine series without forced induction. And if they are going to retain the stock fuel system (CIS) then it's simply not possible. The route for the air flow must move an hydraulic fuel pressure door then twist and turn it's way thru a pipe less then 3" in dia. The delay signal alone from the door to the valve makes tuning for high performance next to impossible as well. CIS works great for what it is and is OK but it's also been surpassed by EFI for a plethora of reasons, heck carbs would make more power.

100hp/liter is a pretty reasonable ask I think. The stock head flow is enough to do it and the 4v engines are in 260ish range once the CIS is removed. The 2v engines are way cam lift limited though....and the ports are big and weird which doesn't help (Sorry Chris) which is why the Michelletto (sp?) cars used the 208 heads.

To the point though, the hp lies are everywhere and have been for as long as I've been playing engines and they get away with it........because people want it to be true. Just buy this and bolt it on and in 30 minutes you get another 100ph, what's not to like? Much like loud=fast/hp....or hearing problems in the making.

Still vote for a (longer if necessary) paper that most engine people can read and understand. It doesn't have to be brought down to the "Hot Rod Magazine" level by any means, but just a thoughtful treatise using fairly neutral language.

My motto has always been "Power is in the heads, and friction reduction is in the short block"

Since we measure Tq and calc Hp a more useful metric would be Tq/L, I've read that Liters consumed per Hp is a more useful metric as well, the equation being ((RPM*Litres*.5)/Hp) At the very least it brings the where in the power band the performance of the engine is as index-able to other engines.

In any case yes mid 200's is very doable, upper 200's gets a bit more difficult and cracking into and beyond 300 is not easy at all and requires significant modifications.

TQ/liter is interesting but IMO not very helpful because it gives you no idea what you can do with the torque. If you can spin it twice as fast you can live with 1/2 the tq/liter and give nothing up or if you can make equal tq/liter at twice the rpm you have twice the engine.....but its way way harder to keep filling the cylinders well as rpm goes up.

That is kind of how the tuning I have on the V12 works. By tuning to the 2nd harmonic in the header and intake the "mid-range" tq goes up but it kills "top-end" cylinder fill. But I've designed n engine that can fill the cylinders well past were I'm comfortable shipping the engine so the mid becomes top and the specific tq is very high. The trade-off (if it works as planned) is the engine is peakier than a more conventional tune.

The 4v 3x8 engine will make 100hp/l with very little effort...but part of that effort is removing the CIS