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Romans 2005 Toyota Echo - Exhaust in progress / new big block setup


Roman

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On 02/06/2022 at 21:49, Roman said:

I guess some of these generalizations change again once you start doing 20k rpm and reaching supersonic port speeds or whatever. 

Looking forward to this in 2025 judging by the current rate of 1NZ development.

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I got a second half printed, still needs a few tweaks for the rail mounting.
But before I get too carried away I can at least test how this new intake runner length/shape changes powerband. Just using the inner rail.

284924839_714393926436082_3857399506894588766_n.jpg.757b9ebfd42a0dbf083cc517994c9222.jpg

Interestingly the main difference was that it needed heaps of fuel pulled out around the 3500rpm range. 
It had a bump around the 6000rpm mark, needing around 5% more fuel to reach target. 
But then above that it was slight losses in the 1% sort of range.

I havent adjusted VVTI to suit any of this, so I might be able to claw back most of the losses, maybe raise some of the good areas too.
But it's kinda looking like a slightly shorter intake would work good if I want to bump that 6000rpm peak a little higher. 
There's definitely no new bumps coming into play at the higher rpm range though, that were previously out of reach.
Which is fine by me as this ever so slightly conks the bonnet on one of the runners. It would fit fine if they were just a little shorter.
Also make a future airbox solution a little easier too.

This is a comparison of the full throttle fuel table changes needed to reach goal air/fuel ratio.

image.png.67c845378be578aae3b118f329f14d9c.png

This is a cross section of current setup. It would be tempting to just chop some length out of the lower part near the throttles, but then the injectors would end up a bit closer.
Ideally want to keep them as far out as I can, to give the concept a fair trial whenever that might eventually happen.

image.png.2e4f402448891b4f7dc2552ada46343d.png


Ahh well, back to the drawing board...

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I've asked you a million times.  but what is your runner length to head, and guesstimate to the back of the valve?     as you say maybe long enough already. or in the no mans land before getting another "peak"

Maybe try similar to what you have,  but  put a  taper  across the whole trumpet.  a few degrees included angle  is good.    seems to be a tiny bit in it.

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hmm yeh pretty sure you'll be still in the hole at that length.   I'd try another 50mm longer.  taper along the whole runner, thats a little less aggressive than whats in those throttle bodies.     bendy ones like you had before will be fine. long as long radius.   maybe can use the radius of the bend to fit the injectors on top side with less  angle.     either way will be worth trying longer with/without the outboards. 

 

something like so,  

da.png.a88ab2dcebed73731d2c1240f14f3760.png

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On 12/05/2022 at 12:21, Muncie said:

Stand the whole arrangement up like an IDA Webber on a rotang and chop a hole on the bonnet. 

I'll chuck $20 towards a spare bonnet and loan you a grinder..... 

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I'm excited for exhaust stuff. I think you will see big gains. 

Anecdotally, my x1/9 sounded amazing when I put 40s on it but wasn't really all that much gruntier. Then I made some headers based roughly off the Guy Croft opinion spec, although smaller pipe sizes cos it wasn't a race engine and I wanted it to fit the bodywork, and I immediately gained 800-900 revs and a big increase in livelyness all around.

So yea, make it happen ....

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