Roman's 4GR V6 Carina discussion thread

[Truenotch]

6 hours ago, Roman said:

I found the picture of the barrel setup in the V8 race engine. 

The lifter arrangement in this engine is really interesting. Pretty sure the RV8 was designed in the USA, so they must have rockers ingrained in them.

[Roman]

Yeah lots of interesting things in those pics. I wonder if thats just lighter or more reliable than a bucket setup? 

 

[yoeddynz]

I personally think your induction system just needs more mandolorians. 

[fletch]

5 hours ago, Truenotch said:

The lifter arrangement in this engine is really interesting. Pretty sure the RV8 was designed in the USA, so they must have rockers ingrained in them.

 

2 hours ago, Roman said:

Yeah lots of interesting things in those pics. I wonder if thats just lighter or more reliable than a bucket setup? 

 

Looks like it allows a pretty wild ramp on the cam.

Maybe lighter and less friction than a bucket. Smaller valve stem/lighter spring?

[kpr]

Thats a finger follower setup is it not.   lighter than bucket setup.  for all the rpms

[BlownCorona]

oh he also mentioned that undesirable things happen with outboard injectors and butterfly valves which likely explains that indy car setup with the butterfly way out on the end of the trumpet making its outboard injectors actually inboard. 
i can ask him to elaborate if you want but i don't think your going with outboard injectors anyway. i expect it probably something like dragging the fuel out of suspension when it slams into a partly closed throttle or something?

[Roman]

Yeah I'm not going to run outboard injectors. 
But always interesting to hear some other perspectives if he's keen to yarn about it!

It might be to do with that when you slam throttles shut, then it generates vacuum.
So it lowers the boiling point of fuel so it clears off all of the residual fuel on the walls pretty quickly. 
But if it's ahead of the throttles, it just sits there. 

I ran the echo with fuel rail mounted ahead of the trumpets, and surprisingly it idled absolutely fine. 
At full throttle the fuel map didnt even need any adjustments either. 
But transient throttle was really gross, and I dont know if there's any good way to make that better.
There werent any apparent benefits from it though, car wasnt any quicker.

I still think the only good reasons for outboard injection is for engines that have poor mixing inside the cylinder (Super short stroke) so they need to premix it more in the intake. 
Which is why some engines seem to get gains from it, others dont. Because you're only "gaining" what a longer stroke motor achieves inside the cylinder anyway.
 

 

[Truenotch]

1 hour ago, Roman said:

I still think the only good reasons for outboard injection is for engines that have poor mixing inside the cylinder (Super short stroke) so they need to premix it more in the intake. 
Which is why some engines seem to get gains from it, others dont. Because you're only "gaining" what a longer stroke motor achieves inside the cylinder anyway.

I reckon charge cooling is the other benefit for some engines. Both you and @kpr showed minimal gains from trying it and you both had plastic parts insulating your intakes.

I wonder if I'd see more benefit because my intake is all metal and gets quite hot... I really should test that theory sometime...

[Roman]

Yeah that would be interesting to see, especially with a surface mount thermistor on the runners. 
Because the metal throttles on mine would get icy cold.
 

[kpr]

Other thing that seems to happen, is it moves the power curve around, by altering the effective intake length.  can see the peaks and dips get pulled down in rpm with the injectors moved out.   Im sure high end race car people know about this.     But if average joe moves injectors  on an intake that's slightly the wrong length. could be decent gains from this alone.

So yeah, if the stars align and combo of things work together.  probably looks to be big gains.    If take all those factors out probably still little gains. 

If 1-2hp to be had.  high end race car engine = yes

 

 

 

make  intake 30mm longer and the power curves start to line up 

 

 

 

[Roman]

Bit of a mindfuck with my throttles.

One bank has a 4 pin plug and normal voltage divider circuit.

Second bank has 6 wires, and i assumed 2 separate 3 wire circuits.

But nope, its got magnets & shit.

Im thinking its hall effect but i have no idea how the wiring goes. Or if it would likely output a variable voltage or a frequency or whatever.

Anyone (by which i mean @h4nd ) have any idea?

 

 

 

[h4nd]

Ooooh, blue caps!! Shiney!

Ain't got nothing for you until you fish out the board and show me the chips, sorry.

[xsspeed]

i see the problem

[Roman]

This is the other side

 

[h4nd]

Oh, tricky. Drawing a blank so far, will look up more places later. Got OEM part number?

[Roman]

Looks like its a Melexis rotary position sensor.

Too complex will adapt a regular tps on.

[h4nd]

2 hours ago, Roman said:

Looks like its a Melexis rotary position sensor.

Nice find: datasheet here: https://media.melexis.com/-/media/files/documents/datasheets/mlx90324-datasheet-melexis.pdf

Arduino code for a cousins here: https://www.melexis.com/en/documents/tools/tools-mlx90397---firmware-for-arduino and here https://github.com/melexis/mlx90392#readme PC stuff

Prob easier to gut it.

[flyingbrick]

Loving your new dash idea! 

Does it allow for variable brightness?

EG, bright enough to see during the day without illuminating the whole cabin at night time

 

 

[Roman]

Yeah they are dimmable and it definitely needs it.

On my last one I had an LDR connected so it would dim or brighten in near realtime (dampened a bit)

It was amazing, come over a crest so sun is shining on it, could still see it fine.

Needs some sort of failsafe though as if it defaults to full brightness at night time itll burn a hole through your head.

[keltik]

How resilient are Carina diffs and axles?