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Romans 2005 Toyota Echo


Roman

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The header/exhaust size discussion I always find interesting and ill admit I am not an expert on it

Obviously got to find the balance between torque (via maintaining gas velocity) and flow for the upper RPM (6500+)

If it was me I would probably look at getting the header piping as close to the exhaust port size as possible, maybe do a 4 into 1 or a 4 into 2 and then 2.5" to the back.

Maybe go 3" if you chuck in some restriction or plan to go turbo later :p

@kpr exhaust design he did for the 4age may work well here as well?

Do you have to run cats in NZ atm?

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I'm onboard with KPR's school of thought / observations, that beyond the extractors and a short segment after that, the rest of the exhaust is just gas transport. Nothing to do with tuned length, velocity, etc helps. 
Even on his near stock 20v, removing the exhaust after extractors gave gains. 
So yes this will get a 3" pipe at some point, haha.
Adding a restriction or back pressure never helps.

With the porting vs exhaust situation. 

If you look at the big dick swing K motors with custom heads etc, and they will hugely favor the intake side valves, even at the expense of crappy positioning for exhaust side. 
So I think porting will help to some extent even if I have a stink exhaust, IF it's allowing a higher amount of fresh air to be captured at higher rpm. 
I found a chart from someone who ported a 1NZ head. 

So the maximum lift cams you can get for a 1NZ are 9.5mm lift, that equates to 0.37" on the chart. 
So if you look at what an unported intake side flows at 9.5mm as is, its about 160cfm. 
With ported intake side, you now reach 160cfm at about .25" or .26" which is about 6.6mm lift. 

So instead of having that peak flow value at the impossibly fractionally small amount of time that the cam sits at full lift, you've now broadened it, and this goes all the way down the chain embiggening the flow capability of your cam at all lift values.

Which is valuable in this case because I cant actually get any cams bigger than 264 deg 9.5mm lift.

On the other hand, it's still possible that this is going to achieve nothing until I've sorted the exhaust. But that's fine too, because exhaust will definitely happen, just not yet.


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Haha yes, I agree. 
Also it's been enjoyable driving it with the airbox on at night time, because I'm not doorting some poor rural persons kids awake from 3km away haha.
So I'm not at all keen on a loud exhaust. Can hopefully keep it reasonably quiet. 
With my Carina I was surprised how rowdy it wasnt with only straight through mufflers. I'd originally flanged the rear one so I could swap for a chambered muffler to keep it streetable. 
But didnt need to in the end. 
See how it goes.

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7 hours ago, Roman said:

Nah it will be fine*

 

*until it isnt 

9k is probably manageable (just?) Is it still making power and not peaking at 8500? ( next up dyno chart showing it off a cliff at 8600 ;) )

What do you think the weak link will be next?

Rod bolts? 

Oil system keeping up and bearings letting go? 

Oil pump failure 

Clutch? 

10k I'm not so sure If serious lol

Liked your porting comment assuming it does widen the curve and increase midrange sounds good. Part of me thinks yes the cfm required will increase at lower revs due to less intake restrictions but the exhaust will still limit it. Not sure how much you'll pick up or how much wider to start.

 

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3 hours ago, shrike said:

9k is probably manageable (just?) Is it still making power and not peaking at 8500? ( next up dyno chart showing it off a cliff at 8600 ;) )

What do you think the weak link will be next?

Rod bolts? 

Oil system keeping up and bearings letting go? 

Oil pump failure 

Clutch? 

10k I'm not so sure If serious lol

Liked your porting comment assuming it does widen the curve and increase midrange sounds good. Part of me thinks yes the cfm required will increase at lower revs due to less intake restrictions but the exhaust will still limit it. Not sure how much you'll pick up or how much wider to start.

 

Judging by his fuel map and having vvt.  It should at least hang onto peak power for quite a few more rpm.  

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