General induction improvements on the imola

Currently reading:
General induction improvements on the imola

Extreme short trumpets with ellypitical shape on a plate bolted to the throttle body.

Interesting, so like a conventional velocity stack trumpet inside the top bob?

Don't ask me to draw it on the PC. I can make a drawing at a meet.

Would be interested in that, I'll ask around for you next time I'm at a meet. I don't get to many
 
Interesting, so like a conventional velocity stack trumpet inside the top bob?

Exactly

I ran LOADS of different CFD simulations on this theme a few years back and found that a small curved, inward facing trumpet on a plenum inlet helped things hugely! Youre not talking about huge gains (perhaps 20% at most), but its enough to make it worthwhile if youre starting from scratch.

You can do a lot worse than just bringing an inlet pipe into the plenum then cutting it to a dead-stop, but ideally some kind of diffuser works best I found
 
I thought my ears were burning... :D

I amazes me that certain people get so defensive about matter of fact comments and observations. The GSR induction kit is perfectly suitable and cost effective application for optimising the std set-up. My experience (as quoted) is that it has some serious limitations around 70bhp. It was somewhat miraculous that we found 10bhp straight away by ripping it off and mapping it with an open TB. The large plenum airbox I had fabricated resolved this permanently by creating a large stable air mass above the Tricker TB. I'm no scientist but the numbers look pretty good to me.

dynoplot.jpg


Cheers, John
 
Last edited:
every so sorry to cause such a stir..
my thoughts where to modify the bob intake and make it bigger somehow.(to take the 70mm diameter pipe i am fabricating as read)
as i thought.
what happens quicker
if i tip the water straight onto the floor
or if i tip it through a funnel with a tiny little end ?
that was my theory
obviously wrong
by no means did i intend to offend ANYBODY ! in any way

your thoughts please

Austin
 
every so sorry to cause such a stir..
my thoughts where to modify the bob intake and make it bigger somehow.(to take the 70mm diameter pipe i am fabricating as read)
as i thought.
what happens quicker
if i tip the water straight onto the floor
or if i tip it through a funnel with a tiny little end ?
that was my theory
obviously wrong
by no means did i intend to offend ANYBODY ! in any way

your thoughts please

Austin

Unfortunately the comparison you made can't be carried over to the problem you want to solve. Getting the balance of a highly complex system right is the issue really. It has never worked to get the 'best' components thrown together and get the best result.

Ford had to learn a bitter lesson in racing this way, where the works cars wer outperformed at times by privateers with 'inferior' flowing cylinder heads.

Dave Vizard and Gerrard Sauer can terll you a lot about the combination of different flowing components.

When you do a project then it should be developed all the way through by one party/team, which follows one school of thinking.

What you have to consider is that you haven't got a constant flow of gas. You deal with a pulsating flow, which changes things in quite some way compared with a constant flow. And this is only the starting point. Too many vriables change all the time, which create the challenges.

Last year we had to cars on the drag strip. They identical when they left the factory. One was mildly modified, which was performance exhaust, induction and re-map with 280bhp according to the rollers. The other had an enlarged capacity and showed according to the rollers 328bhp and more torque than the other car. The 280bhp one won 3 times in a row by just over half a second. You tell me why.
 
every so sorry to cause such a stir..
my thoughts where to modify the bob intake and make it bigger somehow.(to take the 70mm diameter pipe i am fabricating as read)
as i thought.
what happens quicker
if i tip the water straight onto the floor
or if i tip it through a funnel with a tiny little end ?
that was my theory
obviously wrong
by no means did i intend to offend ANYBODY ! in any way

your thoughts please

Austin

Doesn't really work like that. If it did, all tuning would consist of is putting the biggest valves you can fit in a head and taking a mill to the ports. :eek:

Without an accurate way of testing (which need be little more than dragstrip, some way of measuring air temperature and pressure, and a very good driver) you're unlikely to know what's happening (can you feel 2 or 3 bhp? I think not). And because your gains are likely to be small and incremental, you need a way of recording what works.

What actually happens inside engines is very, very, complex. Bell's books are a good way of understanding the complexity.
 
Back
Top