oil pan 4

iTrader: (1)

Here is a little some thing I made up.
It shows the 2nd, 3rd and 4th harmonic intake air ranges in an engine.
There are more harmonic ranges but they are realy narrow and I couldn't get them.
Current trends have runners getting longer and longer. When you look at SBC to LT1 and LS1.
The shorter runners have longer harmonic ranges but your talking 5th and 6th ranges that aren't very efficient. The more efficent ranges That are shown) are a lot higher up in the rpm range on the short runners and arn't going to be used by a street engine.
For you V.E. to be over, at or near 100% you will need to be in red (second harmonic range).
You see that with the realy long runners that the red is obtainable on a street engine but the ranges are narrow and it would be kind of hard to get those runners under the hood.
This is one thing they hid on the pro stock engines by covering there intake manifolds that and the shape.
V.E.
us & them
I punched in the #'s for a 2.8l and got 75%.
When I punched in the #'s for a honda S2000 engine I got 95% V.E.
That's 20 years 20 more %.
There useing more rpms pure and simple to get that X harmonic range (dont know how long an S2000 runner is).
I'm guessing there running the inside 4th harmonic range.
I say we beat them at there own game with our bigger cube engines but with longer runner intake and higher rpm ranges.
Does any one know where I can find out the later harmonic ranges?
Any one have any engine combos, mainly looking for hp, hp's peak rpm and runner length?
What do you know about this?

AM91Camaro_RS

this is very interesting and kind of along the lines of what i have wanted to see. but, i don't totally understand the whole "harmonic range" thing. are you refering to the "pulses?" i'm figuring our runners to be around 15" long which would have to put it in the 4th "harmonic range" or possibly higher.

Doward

It boils down to velocity vs volume. You want the highest volume, at the highest velocity at the rpm your cam is making the most power.

AM91Camaro_RS

so, are you saying that port size would change that graph?

Gumby

You know as long as it worked well. I am all for function over form. I am betting that if you try to keep it under a stock hood, you would need to compromise to much. If you need to cut a giant hole in the hood as the TB now stick out above it, oh well. Put on a hood scoop.

vsixtoy

Well I don't know about all that up there (Larry the Cable Guy).

What I do know is the Falconer intake has 21"long runners from tip of the velocity stacks (airhorns) to the head intake valve and it produces a an operating range of 1800 to 8000 rpms with a " broad, flat torque curve"

85f-bird

what if the intake stacks weren't necessarily stacks. The problem with trying to fit anything under a stock hood is a huge problem when it comes to street driven cars, this wouldn't be a problem with open wheel racing however, or most modifeds, but for people on the street, 21" stacks aren't exactly great, especially when you consider it still won't be "that" fast, (we'd get laughed at by the LS1 crowed)

This would be my though, a new intake manifold using individual intake runners. You fed oposing cylinder banks with the individual runners, (this gives a better chance for you to maximize runner length and to lessen the degree of bends for the runners. Both banks of runners would have the look and design of a tuned header setup, creating runners of equal length moving towards the front of the engine bay, flat along the top of the engine, or valve covers. Twin thrtottle bodies would open at the runners' collectors at the front, which could be duct into pimping, etc. Also, if feeing opposite banks, 21" isn't really that long. It's less than 2 feet of pipe. My only concern would be the bends in the pipes allowing things to remain under the stock hood, might lose some of that performance in the bends, but it could easily be made up with dowards turbo kit.

Gumby

i think thats where a new intake project kind of falls on its face. If you gotta make it fit under a stock hood PLUS making it work with an after market strut tower brace would kill everything.

I would not be oppsed to needing a 4in cowl hood or other for an intake.

FbodTrek

I read somewhere that there's this thing called the law of 4, or somthing like that. I'd have to dig up all of the articles I printed, but basically what is says is a formula for deciphering optimum runner length by displacement and operating rpm (powerband). I forget where the "4" come into play though . Dang, now I need to dig up that info....

FbodTrek

Double post action hero!

Anyhow here is a rather complicated explanation form the good folks at "How stuff works"
http://auto.howstuffworks.com/question517.htm
ANd I will post more very soon, possibly in the form of another double post...(sorry guys).
And another (the harmonic order thing from above, in a non-specific format...but the law remains the same reguardless of displacement)
http://www.bgsoflex.com/intakeln.html
A really nice calculator
http://www.rbracing-rsr.com/runnertorquecalc.html
there are more but I'll have to find them...

oil pan 4

iTrader: (1)

I like that intake calculator.
I measured my 2.8L intake and hmmmmm....
On a 2.8 the MPFI intake makes peak torque at 5900rpm's
On a 3.4 the MPFI intake makes peak torque at 5000rpm's