Heads...intake Vs Ex ratio's ??
Jon,
Acutally that is the plan, I will have that discussion with a sponsor soon. and I agree that a matched set is the way to go....
However I am the type that try's to gain as much understanding as to the whys and wherefore's which will hopefully lead to a practical application, vs "experimenting" with high dollar toys.
The whole purpose of my original questions was after much reading, and plotting out head flow data it seemed to be a black art and a bit mystical to me....Lol
As for my goals.....1000 FWHP is about the Max I would want for the street car. Once there I may even have to reign her in a bit...we shall see. In reality its all about the sum of the parts working efficiently with each other...whatever the outcome.
Acutally that is the plan, I will have that discussion with a sponsor soon. and I agree that a matched set is the way to go....
However I am the type that try's to gain as much understanding as to the whys and wherefore's which will hopefully lead to a practical application, vs "experimenting" with high dollar toys.
The whole purpose of my original questions was after much reading, and plotting out head flow data it seemed to be a black art and a bit mystical to me....Lol
As for my goals.....1000 FWHP is about the Max I would want for the street car. Once there I may even have to reign her in a bit...we shall see. In reality its all about the sum of the parts working efficiently with each other...whatever the outcome.
Very good attitude. One that I tried to take myself. I have to say that the knowledge I have gained during the course of my build has helped me a great deal. While I would never claim to fully understand how all of this works, I feel I do know enough to call "Bovine excrement" as Jon would say, on several of the popular "truths' around here. If nothing else it somewhat protects me from wasting money.
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Actual data This is a couple of web sites that offer split rockers\data-grams.
A) Click on the info link & read the reviews at the bottom of the page. https://www.zzperformance.com/grand_...=555&catid=104
B) Checkout the various Tech Info - "Tech Reports". http://www.easyperformance.com/
This should give you a much clearer picture.
A) Click on the info link & read the reviews at the bottom of the page. https://www.zzperformance.com/grand_...=555&catid=104
B) Checkout the various Tech Info - "Tech Reports". http://www.easyperformance.com/
This should give you a much clearer picture.
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From: Upstate NY
This is a couple of web sites that offer split rockers\data-grams.
A) Click on the info link & read the reviews at the bottom of the page. https://www.zzperformance.com/grand_...=555&catid=104
B) Checkout the various Tech Info - "Tech Reports". http://www.easyperformance.com/
This should give you a much clearer picture.
A) Click on the info link & read the reviews at the bottom of the page. https://www.zzperformance.com/grand_...=555&catid=104
B) Checkout the various Tech Info - "Tech Reports". http://www.easyperformance.com/
This should give you a much clearer picture.
I could not find the connection to this thread's topic of E/I ratio as tested on a flowbench. Please help me out here.
Thanks in advance.
Jon
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Where it says "for more information on ER rocker arm click here". If you click there you will see REAL WORLD graphs, chart and results between using stock 1.6, 1.9 and split 1.85 intake\ 1.80 exhaust. If you also read the reviews, it will attest to the high RPM gain of using split rockers because of the increase in VE efficiency, as stated by the charts, graphs, scanners. You must open the .PDF document or goto http:\\www.easyperformance.com to view their data as well. EasyPerformance only did testing. They do not manufacture\modify rockers. I do not work for either of them. I simply know of their 9 second V6 results. They obviously look for power everywhere. Any engineer will tell you a flow bench is not real world. These numbers are from a running car on a dyno with a scanner reading the MAF. You cannot get better than that with a flow bench, since it is not a working, hot engine. Only a guesstimate of what would happen on a warmed-up, working, running in the car, feeding the trans, to the wheels, end-use-application.
Last edited by christophero1973; Apr 19, 2008 at 09:00 AM.
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Uh, I did all that before I posted. In many applications with more stuff coming into the engine, increased exhaust lift helps power. You can change the rockers or the cam or both. It's often a good thing. I just don't see the relevance to this thread.
Question for anyone: if more exhast lift helped power on an engine, what would need to be done to the cam if the exhaust port was improved to a higher E/I ratio? More exhaust cam or less cam? Why?
Question for anyone: if more exhast lift helped power on an engine, what would need to be done to the cam if the exhaust port was improved to a higher E/I ratio? More exhaust cam or less cam? Why?
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The relevance is to ratios in and out. The rocker-arm ratio can be imitated on the cam LOBE. Which power? TQ or HP? LOW RPM TQ usually limits the VE at high RPM and now high RPM HP. Many of GM's stock cams have a higher lift on their intake lobes. In forced-induction this is less critical because air is being stuffed(at the sake of HP). But on N/A it rules. You need to differentiate your thinking here. Much more exhaust is only better on FORCED induction. N/A doesn't benefit at the same rate as forced. And it kills TQ on NA. Hence 4 valve heads generating more power than 2 valve heads. Always with the same(or even less) displacement & LESS cam. If all you do is drag race(thinking inside the box) with a specific gear set to keep the engine at a certain level.. sure. But outside this box, your power-band is too limited and so... you will get passed up.
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From: Upstate NY
The relevance is to ratios in and out. The rocker-arm ratio can be imitated on the cam LOBE. Which power? TQ or HP? LOW RPM TQ usually limits the VE at high RPM and now high RPM HP. Many of GM's stock cams have a higher lift on their intake lobes. In forced-induction this is less critical because air is being stuffed(at the sake of HP). But on N/A it rules. You need to differentiate your thinking here. Much more exhaust is only better on FORCED induction. N/A doesn't benefit at the same rate as forced. And it kills TQ on NA. Hence 4 valve heads generating more power than 2 valve heads. Always with the same(or even less) displacement & LESS cam. If all you do is drag race(thinking inside the box) with a specific gear set to keep the engine at a certain level.. sure. But outside this box, your power-band is too limited and so... you will get passed up.
You run an OEM engine design department, right? Which OEM? Curious minds want to know.
Uh, I did all that before I posted. In many applications with more stuff coming into the engine, increased exhaust lift helps power. You can change the rockers or the cam or both. It's often a good thing. I just don't see the relevance to this thread.
Question for anyone: if more exhast lift helped power on an engine, what would need to be done to the cam if the exhaust port was improved to a higher E/I ratio? More exhaust cam or less cam? Why?
Question for anyone: if more exhast lift helped power on an engine, what would need to be done to the cam if the exhaust port was improved to a higher E/I ratio? More exhaust cam or less cam? Why?
most of the exh gases are expelled before the piston is on it's way back up the bore anyway,so i'm sure there are other reasons you want more exh dur. in a given application..
what do you always say?"give the motor what IT wants,not what you think it wants"..
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The relevance is to ratios in and out. The rocker-arm ratio can be imitated on the cam LOBE. Which power? TQ or HP? LOW RPM TQ usually limits the VE at high RPM and now high RPM HP. Many of GM's stock cams have a higher lift on their intake lobes. In forced-induction this is less critical because air is being stuffed(at the sake of HP). But on N/A it rules. You need to differentiate your thinking here. Much more exhaust is only better on FORCED induction. N/A doesn't benefit at the same rate as forced. And it kills TQ on NA. Hence 4 valve heads generating more power than 2 valve heads. Always with the same(or even less) displacement & LESS cam. If all you do is drag race(thinking inside the box) with a specific gear set to keep the engine at a certain level.. sure. But outside this box, your power-band is too limited and so... you will get passed up.
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Oh.. and my thinking is differentiated and integrated, as well as laplace transformed...
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From G.A. Korn and T.M. Korn, Mathematical Handbook for Scientists and Engineers"
"In the branch of mathematicscalled Fourier analysis, the Laplace transform,
, is a linear operator on a function f(t) (original) with a real argument t (t ≥ 0) that transforms it to a function F(s) (image) with a complex argument s. This transformation is essentially bijective for the majority of practical uses; the respective pairs of f(t) and F(s) are matched in tables. The Laplace transform has the useful property that many relationships and operations over the originals f(t) correspond to simpler relationships and operations over the images F(s)."Shoot, I had to look up "bijective".
Jon
