Roman's 4GR V6 Carina discussion thread

[shrike]

Can you flip it so the MAF is on the bottom?

[Roman]

Nah not enough room. 

Doesnt matter though, they wont be staying there long term. 

Once everything is balanced up properly, and I've got some sort of airbox in place. I could probably just fit a MAF per bank easy enough. 

But it will be interesting to see if it's helpful to get the motor balanced.

[Roman]

Ah yeah,they all fit in sideways no prob

 

[shrike]

10 minutes ago, Roman said:

Ah yeah,they all fit in sideways no prob

 

I wasn't sure if they would upside down as the pic was misleading on space to the cam cover 

Good they fit sideways so that you can shut the bonnet

[shrike]

@Romanhow are you splitting the lines to the fuel rails? possible its running 1% more pressure on one side or something stupid like that? 

Can't remember if your running deadhead or return setup etc 

You flow tested all the injectors right so I doubt its because of injector variation

[Roman]

It's a returnless setup, using a fuel pump that has the FPR built in. located down by the gas tank. 

I dont think it relates to the fuel lines, because I've now got a 100% different setup and it's still lean/rich like it was with the other intake. 
So I think its more likely something to do with VVT or whatever. 
Will figure it out! 

I guess there could possibly be an air leak ahead of the o2 sensor on one side. I did weld everything, afterall 😅

[shrike]

12 minutes ago, Roman said:

It's a returnless setup, using a fuel pump that has the FPR built in. located down by the gas tank. 

I dont think it relates to the fuel lines, because I've now got a 100% different setup and it's still lean/rich like it was with the other intake. 
So I think its more likely something to do with VVT or whatever. 
Will figure it out! 

I guess there could possibly be an air leak ahead of the o2 sensor on one side. I did weld everything, afterall 😅

Feeds to both rails would be identical then, cool good to rule that out

Tried swapping O2 sensors from side to side? 

Tried turning VVT off and seeing if it balances? 

[Roman]

I did a plus or minus 5 degrees of VVT timing on one side, didnt seem very sensitive to it.

So will do some more isolation tests tomorrow.

 

[kpr]

Sometimes 5 deg doesn't do much/ anything especially if its real close to where it needs to be.  probably need to  try 10 - 20 deg to make up the difference it was before. 

On the dyno it was coming back together  with no fuel  imbalance at high ish rpm.  still does the same ?

[Roman]

Hard to tell as my testing method is a bit sketchy, hard to hold it steady at lower rpm haha.




It's fairly consistent, those wavy bits look to just be trigger errors from where I was playing around with the cam offset. 

Will check some more things today. 

Either way, it's all heading in the right direction right now which is cool! Down to sorting out the small stuff.

[kpr]

probably not much to worry about.  just few more revs, then you can inspect the combustion on the top of the pistons, through the hole in the side of the block. 

[Roman]

Thanks, let me know when you're ready and you can hold the camera for me.

Ahh I found the TPS voltage on one side wasnt quite right, so what it report as 100% was maybe 95%. 
 

Will do some more test hoons and see if we're better off.

[BiTurbo228]

Do you have the full dyno charts from your session with the V6 and one with the previous engine? Oh, and info about gear/diff ratios and tyre sizes?

I've been mucking about in excel to make graphs like this:

Shows you the difference in motive torque at the wheels (i.e. the thing that's actually pushing you along), by gear for two different setups. This is an MGF VVC 160 vs a KV6 MGF with 3.6 final drive (to check whether you'd still end up with an improvement in acceleration with a KV6 swap even if you drop the gear ratio down for better cruising, which you do).

No idea quite how to interpret them yet (other than 'line higher good')...but they look pretty anyhow, and your setup is a bit of an extreme example with differences in rev range.

Edit: never mind me, found it on your thread...

[BiTurbo228]

I think I've got it worked out. Should be able to answer the question no-one was asking. Yes, the Carina should be faster than the Echo...

KPR's Starlet might be a little more interesting though...

Man, these are horrible graphs to look at. Enjoy!

[Roman]

Haha, cheers. 

I guess what you might want to consider / rescale to. 
Is the fact that the Echo was 800kg flat (excluding 100kg driver) 
and the Carina is 990kg. 
This is where Kris' starlet excels, its got the power of my V6 and the weight of the Echo! 

Anyway, you should have a geez at the program called "CarTest2000" It's great. 
It's what I used to test the concept of the echo initially, as well as some other combos including the carina options I was considering aside from the V6. 

This is the carina with 9000rpm limiter: 

Where the lines cross over, is the best shift point. So you can see that 1st gear and (to a lesser extent) 2nd gear sucks big time.





If I set the limiter to 9700 rpm with same power:

Can see that the car will be faster because it doesnt eat shit on the gear change so badly.





With power "as dynoed" this program speculates that it will run a 12.8 @ 108mph which seems fast. 

But for whatever reason it's assuming my car can do an absolutely hectic 60ft time, which so far it hasnt managed anything like that. 
I think a a 2.3 or a 2.5 sec 60ft is best so far (on semi slicks or street tyres) as this car axle tramps so badly. 
It needs traction brackets, but, I might just be able to brute force the issue with the drag tyres. 

The two variables which HUGELY affect the overall time and MPH. Are how long the gear shifts take, and how much more slippery I make the track to try get the 60ft time to a higher number. 

In saying this, a friend with the same bias ply 205/60/13 tyre has run a whole bunch of 1.6 sec 60fts in a 323 wagon. Which is incredible. Fingers crossed for a sub 2.0 60ft! 






In saying this, there's so many untested moving parts in this car so far. 
That I'm not expecting miracles first time out with the new motor. 
It's bound to have some sort of issues on the day.
Fingers crossed they are minor ones.

[BiTurbo228]

Haha looks like I've spent a day recreating something someone else has already done a little bit better on the internet. If that isn't a microcosm of modern life I'm not sure what is...

In between the MGF graphs and the Carina ones I've factored in rolling resistance and drag. Not sure I've got all the weight variables right though as making something weigh twice as much doesn't change much to do with acceleration (probably missing the force required to overcome inertia). Though, neither does theirs I suppose (though I like the little 'losses' line, that's neat).

I would like to get it factored in though. As you say, it's missing a big part of the picture. Should be fairly simple I think, it's just f=ma and then you could get a graph of acceleration.

Your 3rd/4th/5th/6th looks pretty good already, but yeah I can see how a couple of hundred more rpm would help with the first few gears.

[BiTurbo228]

Yep, doing acceleration sorts it out. Luckily the Carina still works out ahead of the Echo

The Starlet's now way ahead though. Would be interesting to see the difference when you've got it dialled in a bit more.

[HumberSS]

Could you do some sort of bodgery like using a raspberry pi/Arduino to receive input from ECU/throttle and then control two stepper motors via some cheap drivers and have the compensation table done in the Arduino? So you are passing one signal to the Arduino but it then splits to two signals with the compensations? It's total fuckery but might get you out of a bind and be relatively cheap..

[Raizer]

[mjrstar]

Plug that second ecu in, and run the v6 as a pair of 3 cylinder engines to really give your tuning skills a workout.