Exhaust megaphone angle - Dyno tested 

Anyone keen to send me some 3d printed or any form or low cost velocity stacks/trumpets for that matter. So we can do another round of this: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-G8L9_XO3iCw.html Will throw up a post with details if there is enough interest. Maybe someone can beat my normal intake setup?!

Would be interesting to see the difference between 4-1 header and 4-2-1 header.

I love this channel. A bunch of tuning stuff thats actually dyno tested and not butt dyno tested

Holy shitballz - i checked the link you put in the comments for the slip on collectors and then checked the main site - you've got a history of beasty old toyota stuff - its an awesome read through to see the other projects and fun you've had! I also love the repeatability of the dyno your using - your the only other youtuber i click like on before i watch the vids, the other one is a DJ so not even car related lol - pity you stopped updating the blog site - but im hella thankful your doing youtube stuff :) I didnt realise just how modified the whole starlet was until i went through the website you had been using :)

3 inch straight pipe is basically a termination box for up to a 2.4 liter 4 cylinder. You'll be hard pressed to find anything substantially better than that.

Wow @5 degrees, the power goes smoothly. Just 1 deg, made a huge diff. You are 4A GE mage.. 👌👍

This is one of the best, car tuner channel in youtube.

Engine intake test suggestion. Some 4 stroke bike engines use a 2 stroke type reed valve in their intake in conjunction with a large duration intake camshaft. They claim the reed valve gives a good mid range improvement in power by reducing the reversion of the long duration. Each cylinder would need its own set of reeds. Not an easy test though.......

Hi from the uk I remember megaphones being used on single cylinder race bikes or 1 per cylinder. from what I have seen and used a 4 into 1 for peek power or a 4 - 2 - 1 for system with a bit more mid range, not forgetting that the length and diameter of the primaries is the first step Great vid car sounds awesome

Love these videos so much

It sounds great eitherway but have to admit the megaphones sound nice, i'd be tempted to use best result from that just for the slight change in noise it makes.

Good test! On 2 strokes the expansion pipe cone geometry dependent on port timing. Be interesting to see a vvti swing with a range of megaphone set ups or a set of cams with massive overlap

Nice that 4age sounds awesome

Interestingly when I measured the factory secondaries on my BMW 3.0 ( N52) they had a very slight increasing taper from the cats all the way back to the merge point at the 1st silencer, a couple of mm over 1m length , ( the rear bank secondary was also very slightly smaller than the front bank , presumably to compensate for the shorter length from the manifold to the merge point) Was planning on fitting N55 with larger secondaries cat back, but dropped that plan when I found out the lengths BMW had gone to when tuning the secondaries on the non turbo car, and only fitted the larger N55 exhaust from the centre box back - which still made a big difference...

You should try a NASCAR style "boom tube".

Diverge and don't reconverge, and adjust the distance of the divergence from the header collector

Interesting that 5 degree divergence filled in down low and up high. All the venturi papers I've read suggest around 7-8° is ideal for air @ 20°C. If exhaust gas density accounts for the difference then 5° makes sense.

Wow always good contain you are a god of knowledge buddy ! I wish i would have been in your country to let you my zzt231 celica and let you test anything you would have like to !

Sounds mental

The only real big difference will be if you do total exhaust length tests. Like start with a total exhaust length of 5 meter's or something and just cut off half a meter over and over.

it would be super interesting to see comparison between 3 inch exhaust, double 1.5 inch and double 2 inch. oval exhaust would be interesting to throw in there

can u make a motorized runner manifold so it adjust through the rpm range .. see if u can smooth the bottom end better

Love from Ireland❤

that bonnet stay gets some abuse haha, mean vids man

Would love to see a pov drive of the car especially going into rpms

The longer pipes merge the better the flow. We'll with water. I've always wanted to test a longer merge on the collector

It would be cool to compare a 3" single pipe to a double 2" pipe or a 2,5" oval full exhaust

That motor is just terrifying! One day…

Interesting results, thanks for sharing. I'm now subscribed. Have you considered doing "cookie cutter" style exhaust tips. I've seen them used primarily on Porsches from the last 60's. to mid 70's.

Nice welding on em cones

ok this is now 2 stroke territory

Imagine making a V8 out of this engine :)

Have you tried that anti reversion cone? I am not sure that thing really works.

test stepped exhaust headers and give bsfc data

can you do a test on that ep3 you had in?

787B ran a variable trumpet intake. I guess maybe controlled by vacuum or lack of vacuum. I was hoping for a better result with the expansion exhaust, and then the 3" full exhaust came along and ruined everything😭

When you change the angles it looks like the overall length of the megaphone is changing?? Is it possible to keep the length constant with a custom made tube between? I can donate some Watties golden peach tins -- with or without contents -- if that helps.

Have you ever played with a Venturi in the exhaust where it initially goes down in diameter before going back up, or an anti reversion chamber?

what theory is behind megaphone, it has some benefit for 2 stroke but for 4s?

Given the range you tested and the full exh vs 3" muffler, it doesn't look like you're getting anything meaningful out of the megaphone. 6hp at the last 400rpm doesn't seem like it's going to help anyone. Great test none the less.

🚀🚀🚀

you should try unequal length headers

you tried the cone wide to narrow to wide again

Have you changed the different lengths of intake tubs?? Yet

Do you run the MRP N2 cam belt stabiliser idler? Would be interesting to see if there's any difference with one fitted on the dyno.. I've noticed Honda B series have an extra pulley on the right side because I think the water pump is driven by the cam belt, also noticed RBs have an extra cam belt idler and 4AGE doesn't

Oi m8 what front lip do you got on there?

any plans to ever consider a 2zz material?? please...

I don't understand the point of an expansion chamber on a 4t.

What you are doing is Fricking awsome! If you could change the length of the pipe to the expansion chamber, I suspect you could change the effect. In theory by dynamically changing the length (dependent on load = flow), you could optimize the supercharging / scavenging effect over a wide rev range. BTW, valve timing overlap will really start to matter now.

Stepped Primary Exhaust Extractors ?

interesting :3

Why is 10krp so sensitive to changes?