Roman's 4GR V6 Carina discussion thread

[keltik]

4 hours ago, h4nd said:

sliding trombone section 

I don't know enough about how trombones work but I'm imagining this thing playing the final countdown at highway speed using your spare ethrottle actuators on the exhaust trombone slidy bit

T-VES

[xsspeed]

https://www.youtube.com/watch?v=OY0l7NqRrYM

[Roman]

TVI-YES! 

[BiTurbo228]

On 19/12/2025 at 01:29, Stu said:

Nah m8 just 6 of these

 

Right, hear me out.

12 of these (or slightly smaller strommys), one set on short runners and another set on long ones. RPM-actuated butterfly to swap the inlet tracts to get the pulse tuning right.

You really want to hammer that rpm-transition bog as each cylinder is briefly fed by both carbs...

[Roman]

get out 

[Raizer]

[cletus]

Id be really interested in a carb vs efi comparison on something like this or kprs starlet to see how much difference there is  

[Roman]

If someone has a bunch of carbs I can chuck on it for lolz, I am not opposed to testing the idea. 

But I'm not paying for any 😄

Would be interesting to see how it would go with carb(s) VVTI locked to a static position, and some crappy ignition timing. haha

[tortron]

pretty sure I have 6 1 1/8" SUs, but Burt Munroe already proved 1 big SU is the way to go

[kpr]

1 hour ago, Roman said:

If someone has a bunch of carbs I can chuck on it for lolz, I am not opposed to testing the idea. 

But I'm not paying for any 😄
 

This ^  plus the fuel system change.    when people (lots) ask me to try it.       Then changing it all back.

Is up there with. "Try different weight flywheels"  

[Roman]

These two clips sound almost identical except for some turbo woosh 
 

But then both sound like less rpm than this 
 

 

[mjrstar]

Im pretty sure you've got a pair of G16e's under the hood at the moment.  

 

The echo looks like a real blast to hoon on the track, and has a bit of a b series honda vibe soundtrack.

[VitesseEFI]

That Echo was just epic…. 

[nick_m]

Can’t say I’ve had much to do with exhaust noise tuning. But I have done one twin exhaust to customer supplied specs on a bmw I6 based on the  group C specs of the time and it absolutely plundered the power and torque curve. When we redid the exhaust to more traditional specs it make waaaay more torque

So I don’t really have much helpful insight just more vague info to muddy the waters haha 

 

[Honda Ass Dragger]

Did Chat GPT consider a Z Pipe:

[kpr]

The  AI  probably read your previous post and is long game trolling you, to make it sound even more like a 3 cylinder.   

Im assuming you will want to keep both sides pretty much bang on the same length, not to end up with the above.

performance wise, through the middle at least.  running the cone out to 3" after the choke and staying 3"  till after those first reso's, then dropping back to 2.5   maybe of benefit. but  may effect the sound. 

[tortron]

On my high performance V6 (Buick) the left hand bank goes pretty much straight to the back of the vehicle, the right hand does a nice big dog leg around the transmission pan (yes 5mm too little to remove the pan with it in place of course) giving that side say 2 metric ft more length

 

this results in a very nice, traditional V6 Mooo

[VitesseEFI]

Surely the AI suggestion just gives you 2 three-pots singing side by side…..

Try it… then add X-pipe/H-pipe….😛

[Roman]

2 hours ago, kpr said:

The  AI  probably read your previous post and is long game trolling you, to make it sound even more like a 3 cylinder.   

Im assuming you will want to keep both sides pretty much bang on the same length, not to end up with the above.

performance wise, through the middle at least.  running the cone out to 3" after the choke and staying 3"  till after those first reso's, then dropping back to 2.5   maybe of benefit. but  may effect the sound. 

Yeah hope for the best expect the worst. Then get the worst. Just another chapter of V6 life

I asked about whether its just gonna sound like 2x 3cyl engines and its very insistent that it wont.
However it does say that each side needs to be as close as possible to the exact same overall length.
Anymore than 150mm length difference and it'll sound like a 3 cyl again. 
If I do end up merging them or X pipe, I need to get both sides equal to past the gearbox anyway. So no harm it trying this first.
I think the challenge here is getting all this stuff to work, while still having a long exhaust pipe.

Chatting with a gentleman on facebook, he's shown me an interesting video comparison of a Stratos with 3-1 exhaust compared to merging. 
The one with the merge sounds absolutely excellent but holy shit it must be ear piercingly loud as it's essentially open headers.
The 3-1 setup looks to have muffler length that would kill a lot of the higher frequencies but I doubt it would sound as good even if they were shorter. 
So I guess the question is, does a long length of pipe after the merge make the pulses merge back together and kill the high freq. 
It will be easy for me to try a 2-1 join that is very far back. 

It's interesting to see that the stratos with the 2-1 join exhaust has all of the room in the world for a longer muffler, but keeps it very short. 
That's still a relevant part of the puzzle I reckon.

Also the Georg Plasa car that sounds godly merges 8-4-2-1, but the 2-1 merge is nearly right at the back of the car, and doesnt look like there are any mufflers.

So TL;DR: 
Chatgpt sucks (probably)

 

 

 

[Muncie]

Hey, have a checkout of this guys channel he goes deep into making things sound good and make power. He uses megaphones and muffler design to get what he's after and graphs occasionally (selling point i know) 

https://youtube.com/@fluidmotorunion?si=5MS-3vtZLQ4LbeZz