Roman's 4GR V6 Carina discussion thread

[shrike]

26 minutes ago, Roman said:

Might not be any point with my motor.
Since it's got a longer rod ratio than the 2GR, the piston dwells at TDC for longer.
So it would likely hit pistons sooner than a 2GR.
Maybe cant make use of the extra range anyway. 
Will see. 

Ordered big cams! Exciting 

All good, im assuming the Camgears are the same between motors? unlike the K20 and K24

Just thought it might give you inspiration :p he did have to clearance the piston valve pockets to use the extra range as well 

[Roman]

Yeah the reason thats needed is because the FXE pistons have shallower cut outs, which is part of how they get the higher CR. 

Hopefully the factory valve pockets on the 4GR are alright to get the cams setup on the factory timing marks.

[Sambo]

This is better science than I did on my final year engineering project for uni. I award you first class honours.

[GARDRB]

On 24/04/2025 at 21:13, yoeddynz said:

Go to 3min.. 

 

 

I got all excited, I thought that was the @Esprit and @Snoozin Lantis

[yoeddynz]

I don't think I've ever seen theirs. Any vids of it out there we can see.

Great sounding engines with the right exhaust these

[Rhyscar]

Dave science is a great thing. Interesting about exhaust frequencies and 100% makes sense based on other reading. I think the muddled frequencies are initiating further up the exhaust (which I think you've already realised), and putting restrictions in further upstream will net better results.

Essentially, you're letting the resonant waves do whatever they want throughout the length of the exhaust and then saying "look settle down, and squeeze yaself through this tiny hole". It's going to be slightly better as you're narrowing the range of frequencies at that point, but isn't actually solving the problem. 

 

Awesome info and investigation though!

[Roman]

Yeah it was just the easiest thing to test and rule out first. 

But imagine doing it the other way, then doing that last and finding it's what made the difference. Would be gutted. haha.

Here's some ethrottle skids

 

[Muncie]

Sounds mint once the induction starts doorting. I love the sound of 6 though so heavily biased and loving this project.

[Muncie]

To bridge what your doing here and what i did i built basically this thing minus a cage 20 years ago, mechanical injection with open throttle bodies but destroked from 2500cc to 2000cc best i got was 9200rpm (old monster tach probably inaccurate) and it sounded amazing flying by.

Exhaust wise i found keeping the exhaust short made it sound best. I had a super44 3" flowmaster under the drivers seat and it sounded glorious with a full exhaust and 3 mufflers it was as loud sounded completely different but about the same volume with 3 mufflers.

What's your firing order? Above is 153624

Considered going side exit?

 

[mjrstar]

Oh yeah, put 10 mufflers on it and let the intake do the talking.

[Roman]

On 17/05/2025 at 10:02, Muncie said:

To bridge what your doing here and what i did i built basically this thing minus a cage 20 years ago, mechanical injection with open throttle bodies but destroked from 2500cc to 2000cc best i got was 9200rpm (old monster tach probably inaccurate) and it sounded amazing flying by.

Wow, that's cool as! 

Sounds sweet. 

Yeah I am basically going to bin nearly the whole exhaust except for extractors and try some other stuff. Hoping to keep the noise down a bit.

[yoeddynz]

I can send you all my offcuts

[GARDRB]

Is it worth just sealing the airbox against the bonnet??

[yoeddynz]

I'm seeing an opportunity to have 6 of these sticking out proud of the bonnet

 

[Roman]

Sealing to bonnet: Have thought about that, but nah dont like that idea. 
As I doubt it actually seals very well.

Like if I'm going to have an air filter, I want it to work 100% properly.
So I can be confident of driving it on gravel etc.

But it does make me think that I might mount the filter a little close towards the engine, hard mounted to the airbox. Then the front section over the radiator can be flexible without the flexi section risking ingress of debris if it has an issue.

Alex - I cant use ramflo filters, because the extra torque would twist my chassis off the line 

[yoeddynz]

But imagine the doorty sounds. 

 

And the fires. 

[Rhyscar]

What does your filter area end up being? Seems a little on the small side compared to the size of a factory filter.

[440bbm]

20 minutes ago, Rhyscar said:

Seems a little on the small side compared to the size of...

thats what she said

[Roman]

2 hours ago, Rhyscar said:

What does your filter area end up being? Seems a little on the small side compared to the size of a factory filter.

Yeah that's a fair point. Itt looks a decent size in person.
But looking up the car's that it fits, it's all fairly sedentary Peugeot stuff.

It's 330x100mm with 50mm deep pleats. 

So it's still considerably considerably more filter area than nearly any pod filter I guess.



 

[keltik]

I guess surface area is more related to effective service life than anything else.

Might have to replace it every second engine instead of every fifth.