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Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt


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Longer runners are only good if you don't make the short ones short enough to get to the next harmonic. You can get 3rd harmonic to work as low as 4000 ( which also means that your 2nd and 4th harmonics are going to be in the usable rev range too), which IMO is much better as you have to be an amazing driver to keep and engine on the boil ( the reason most BEC's are much slower than theoretically possible). 

 

So better throttle response, less restriction, easier to change the Harmonics for tuning, better packaging, better noise, better looks.

 

 

DDDOOOOORRRRTTTT!

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Info about induction Harmonics, the numbers don't mean much but the statements do.

- Induction System Tuned Lengths - ( Cylinder Head Port + Manifold Runner )
1st Harmonic= 31.082 (usually this Length is never used)
2nd Harmonic= 17.641 (some Sprint Engines and Factory OEM's w/Injectors)
3rd Harmonic= 12.316 (ProStock or Comp SheetMetal Intake • best overall HP )
4th Harmonic= 9.694 (Single-plane Intakes , less Peak Torque • good HP )
5th Harmonic= 7.865 (Torque is reduced, even though Tuned Length)
6th Harmonic= 6.617 (Torque is reduced, even though Tuned Length)
7th Harmonic= 5.711 (Torque is greatly reduced, even though Tuned Length)
8th Harmonic= 5.023 (Torque is greatly reduced, even though Tuned Length)

 

Note> 2nd and 3rd Harmonics typically create the most Peak Torque
4th Harmonic is used to package Induction System underneath Hood

 

 

 

If you aren't already, sign up to Speedtalk, even if it is just so you can read this thread.

 

http://speedtalk.com/forum/viewtopic.php?f=15&t=37899&sid=844b0d3ee57db11a2bd1c8c348b51ea5

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Longer runners are only good if you don't make the short ones short enough to get to the next harmonic. You can get 3rd harmonic to work as low as 4000 ( which also means that your 2nd and 4th harmonics are going to be in the usable rev range too), which IMO is much better as you have to be an amazing driver to keep and engine on the boil ( the reason most BEC's are much slower than theoretically possible). 

 

So better throttle response, less restriction, easier to change the Harmonics for tuning, better packaging, better noise, better looks.

 

 

DDDOOOOORRRRTTTT!

My engine isnt peaky. Well, it does make max hp right on redline. But thats because it needs a higher redline, not that it feels gutless at lower rpms.

The throttle response is already good.

Factory manifold is a negligable restriction, it's got bellmouths in the runners already, and the runners are a larger cross sectional area than blacktop 4age throttle bodies. When your throttle(s) are wide open, it doesnt really matter where they are?

I dont need to change the harmonics because they're already designed for the motor and gives it a good powerband.

The packaging is worse, because quads wont fit properly.

Better looks in the engine bay is irrelevant to me.

It wont sound any different because I'd have it in an airbox regardless.

I get 8l per 100km when driving it like normally, and I drive it on gravel roads etc so good filtration is mandatory.

 

I think I've done about 8,000kms in 6 months so far, and last air filter change there were all sorts of insects/debris/etc stuck in the filter. Open throttles or anything like alpha N mean compromises I'm not willing to make to filtration or fuel economy or whatever.

 

Either way it's a pointless conversation because I've got zero intention of going to quads even when I get an aftermarket ECU Going to keep running a hotwire MAF as well if I can :P

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Aahh so just some gif files from my thing before.. Big gif files so click the links.

 

http://iforce.co.nz/i/1dm2kvwj.4fd.gif

http://iforce.co.nz/i/tmwz3uk3.fvw.gif

Most of the air spills back out of the big trough thing so could probably keep downsizing it until that stops happening.

 

Or keep lowering the vehicle speed to see how big it needs to be to work at XYZ speed.

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