Roman's 4GR V6 Carina discussion thread

[mjrstar]

The ins and outs of these direct injection injectors aren't really my jam, but is there a chance due to high operating pressures that these are pilot operated, relying on fuel pressure to actuate?

[Roman]

I think they just run on a zillion volts and are peak and hold. 
Every aftermarket ECU that can control DI decently, needs to interface with the OEM injector power module thing, or use a 3rd party one. 
This motor from factory has a little computer thing that bolts to the front of the engine. 
It accepts normal-ish injector inputs into that, and I think fuel pressure and some other stuff. Then magics the output of the injector to give the desired amount of fuel I think. 
Unless you want to run stratified charge mode, I dont think the benefits are hugely pronounced over port injection for this kind of thing. 
But, yeah. Either way, the DI pump gets cut off so the engine can fit, and the big cams wont work with it anyway. 
Making some press fit dowels or something is still the best solution, as it leaves more room in the Vee for my clusterfuck of wiring haha.

[anglia4]

That makes a very cool noise.

[Nominal]

I'm waiting for the 89000rpm bit.

[xsspeed]

lold

/im waiting for 9800 next

//i was lucky enough to get a sneak peak of the vid the other day and played while in traffic in my car through the radio, it made me feel like i was in a racecar

[xsspeed]

//which i was cos nismo note of course, but traffic was non compliant

[BlownCorona]

great job, awesome engineering yadaa yadda ect ect 

im disappointed that milk bottle didn't get ejected out the side of your shed at mach 1

but seriously, great job

 

[Hurmeez]

Watching the 9k rev video at smoko and I can't help grinning like an idiot. You must be positively fizzing at the bunghole from the driver's seat. 

[Roman]

More just concerned and hypervigilant at the moment, listening out for creaks bangs and so on. and trying to dial fuel in and so on.
It's enjoyable to watch the video though haha. 

One thing I learned yesterday. If  you are revving up your car in the garage.
Try not to hit an ignition only rev limiter, if you want to avoid spraying fuel everywhere 

[440bbm]

doesnt even sound like 9k. wants moar!

[Dudley]

I reckon rev it till you blow the oil filter off

[Honda Ass Dragger]

Is making something like this possible:

[Roman]

Yeah thats what the actuators look like, that operate these throttles on the factory motor. But the actuators are $1000+ each which is nuts.

A few aftermarket options like that but all cost heaps.

E36 units were about $25 each so worth a punt.

[GARDRB]

I have some 6mm dyneema on my little boat. It has a 2000kg breaking strain

[kpr]

That wont handle romans right foot. 

[Roman]

Trying to keep pushing the pedal, this cant be full throttle can it? 

[tortron]

lol, my morrie accelerator pedal was bent almost flat at the bend due to 60 years of flat to the floor driving.

ironically making the throttle only open 70%

[shrike]

On 24/02/2023 at 08:56, shrike said:

So I'm still tipping 200kw+ not sure what the factory rods are like, but not sure if they will do 10k rpm guess it depends how heavy they are and how well its balanced from factory

I am assuming you'll do valve springs as a minimum and be going for custom exhaust/headers might even crack 220kw atw (would love if it got more however :p)

Whats the harmonic balancer/engine dampener weigh? and are you going to run many auxiliaries on the motor?

I've been having a play with the Automation game and well some of the figures aren't super realistic it can be an ok guide/indication sometimes

Couldn't get down to 83mm bore (84.4mm smallest I could go) but with cast rods/pistons it was happy with 8400rpm, would say 9k with the smaller bore is reasonable

ITBs, exhaust etc (with springs) it did 270kw at 10k rpm lol which Im not sure about, might upload something later if you want a laugh?

Update on this with the latest updates

Over 11000rpm it gets valve float (even with best valve springs etc)

Best variable timing shift is at 4700rpm 

This is on 98octane and 3" exhaust and the intake as big as itll go, taking it down to 100% bring peak power to 9100 but is less power at that RPM vs the graph above

More timing does nothing, leaning it out moves the torque 2200rpm later

Bigger exhaust headers moves everything later without power gain, minimal benefit from going to a bigger exhaust (+/- 1kw and peak power is 100rpm later)

Cam is set at 50 out of 100, bigger cam does nothing but rob lower down torque

Forged rods/pistons

[Roman]

Aahh sweet so instead of the 3 quarter race cam used in starlets, this motor only needs the 2 quarter race cam

[Dudley]

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