Narrower Inlet Ports Make More Power.. Aparently

[kyepan 291]

discuss..

 

http://www.mototuneusa.com/think_fast.htm

[jackherer 543]

I think you win the prize for longest time between reposts, I remember this from at least ten years ago!

 

Microsoft FrontPage FTW

 

edit: this dates it

 

If you type the words "Intake Porting" into the Alta Vista search engine,

you'll find an incredible 756,220 pages on the topic !!

Edited May 24, 2012 by jackherer

[GLPoomobile 958]

I love your choice of topic tags (even though you've spelled spurious incorrectly ). I've not read the whole page but is this not pretty much what Sandy has been saying for a long time? It's the not the amount of flow that counts, it's the velocity (or something like that ).

[Sandy 191]

Thank you! Yeah I did think it had a familiar ring to it! You run the risk of over-simplifying it though, small ports will not produce very good top end power if the shaping and section progression isn't right; something that is very specific to the engine and spec.

I don't use a flow bench at all for my heads, I think it's a distraction and rely on what I've calculated, projected and tested. But theorists will tell you that you use the flowbench to achieve maximum flow with minimum port section, so the flowbench is still relevant. The three reasons I avoid it are: I don't want to become too addicted to the results and start skewing my headwork towards what the flowbench tells me, it takes alot of time to re-port etc and see results, most of which will be thrown out by a change of seat cut anyway, I'm kind of averse to taking the normal routes to engine development!

What the dyno sheets don't tell you is how the engine behaves away from WOT and flow testing is generally counter productive on that front from what I've seen, the best heads on the engine don't tend to be the best on the flow bench!

 

Edit... as a post script and I'm not saying it's right, but a Works 2 litre Ecotec JRE had in, had 36mm diameter bodies and runners, about 20% less inlet flow area than a standard GTI6 or Mi16.

Edited May 25, 2012 by Sandy

[j_turnell 137 3 Cars]

As said lots of variables to consider but a classic I see quite often is the Pinto head. Ports are big as standard then people get happy with the die grinder and wonder why it has no mid range torque.