Roman's 4GR V6 Carina discussion thread

[Roman]

@Dudley Not sure if you knew this, but back in the day Toyota engineers were told they need to develop a pure racing engine. 
Which is how the 3K-B came about.
To this day it's the only street motor ever known to be able to run a 4 quarter race cam.

[Dudley]

I think we can all agree, that’s when Toyota peaked technology and performance wise, it’s been a steep downhill slide since, too the point your oil filter housing will blow off if you ain’t carefull

[GARDRB]

On 07/04/2025 at 12:39, Dudley said:

Yeah if you want a 3/4 race cam you really need a old k series head, they have a lovely short turn radius unlike the 4age which really allows the air speed to run big race cams and 45mm black top itbs

@kpr wouldn't have to spend so much time on his mill, I mean lathe, I mean horizontal drill press, chopping up 4ages if he'd started with the peak of Toyota performance instead of messing with that 16v junk

[Dudley]

You can’t teach an old dog new tricks though

[xsspeed]

3 hours ago, GARDRB said:

peak of Toyota performance

Puerto Rico 3T-C?

[lush]

9 hours ago, GARDRB said:

 the peak of Toyota performance 

Clearly he's referring to the m series motors here, they perform so well the head gaskets let some horse ponies out to let their competitors catch up to them so it's not an unfair advantage 

[GARDRB]

35 minutes ago, lush said:

Clearly he's referring to the m series motors here, they perform so well the head gaskets let some horse ponies out to let their competitors catch up to them so it's not an unfair advantage 

An m-series headgasket is just a fuse for all the horse ponies

[Dudley]

Does that explain why my kp was so fast? Having that blowen head gasket for nearly a year

[Dudley]

[Rookie]

@Roman I'm pretty sure you just ran into the problem that dictates almost every dual bank itb setup uses push/pull rods. I think if it was me I would spend a little more time working on that solution as a stop gap. Hell, my BMW motorbike has two throttles that aren't mechanically linked and only one TPS and it runs mint hahaha we all know afr (within the right range) has almost nothing to do with power output.

Good work on the doorts though, A++ would trade again.

[Truenotch]

On 09/04/2025 at 09:51, Roman said:

@Dudley Not sure if you knew this, but back in the day Toyota engineers were told they need to develop a pure racing engine. 
Which is how the 3K-B came about.
To this day it's the only street motor ever known to be able to run a 4 quarter race cam.

Ahem, you're forgetting the 3K-R, which is the only engine in history to overcome a lack of pushrods by running eight quarter race cams (16 lobes!!).

[Roman]

47 minutes ago, Rookie said:

@Roman I'm pretty sure you just ran into the problem that dictates almost every dual bank itb setup uses push/pull rods. I think if it was me I would spend a little more time working on that solution as a stop gap. Hell, my BMW motorbike has two throttles that aren't mechanically linked and only one TPS and it runs mint hahaha we all know afr (within the right range) has almost nothing to do with power output.

Good work on the doorts though, A++ would trade again.

Current setup is probably absolutely fine above 50% throttle (or whatever) so can still drive the car as-is when other stuff is finished.
Speaking of which, I now have the exhaust shape finished and hung.
Added a bunch of heat shielding to things near the exhaust manifolds as well.
Just need to finish welding up the over-diff part then assemble. Then the car can finally can come down off the stands! Excellent 
 
Agree that push/pull rod is a good way to go.
But the problem is unless I get the center rotation point exactly between the banks. I've likely got the same extent of imbalance going on.
Ultimately though I want this car to have cruise control and the throttle blip. So keen to see how it pans out.

Once exhaust is all bolted back in, main thing left to diagnose is the engine (or ECU) voltage dropping off.
Have got a decent plan to isolate the issue but need the motor running to test.

Getting there.

[yoeddynz]

 Just a thought which may or may not work (and could end up looking ugly..) but can you fit tiny nylon balance tubes between each bank? 

[Roman]

Balance tubes are built into my manifolds. Each side tees together at the back of the motor.

But even so, would see one bank or the other go rich or lean depending on how i adjust the cable.

Again its not the end of the world if they dont 100% match up, I can set closed loop wideband to work per bank.

In some ways im just being fussy. But then also if I have to remove the intake later on. I dont want to have to go through some stupidly fiddly process each time to get it back where it was.

[Muncie]

Can you please make your dash flash red and yellow and have "danger to oil filter!!" At 9500rpm I'm sure it'll help the youtube algorithm.

 

[yoeddynz]

Lol @ the chooks running away scared 

[Roman]

Hey if they havent figured it out by the third lap of rb20de noises. Thats on them 

[xsspeed]

Sounds like rb20

/thread

[Yowzer]

Check out the jap exhausts they stick on 350Zs and try replicate that. We used to get one in at work and it sounded mental

Obviously you'd have to go a different layout to make it fit, but some wacky crossover pipes swapping between mufflers seems to be the go

[Roman]

Yeah it's only got a single muffler on it at the moment, so I guess not very refined or whatever / worst case scenario.

I'm glad the noise level is down though, and I can at least start putting the tune together decently.

Buuuut yeah. needs work.