Roman's 4GR V6 Carina discussion thread

[Roman]

From what I've seen/read the flow restriction from an open butterfly is essentially negligable if your runners are the right diameter. 

I think the only practical benefit of a barrel is that they can be the same (non circular) profile as the port. 

I found some pictures of a really interesting intake setup from an Indy Car a while ago. 
They had butterfly throttles but mounted way out at the tip of the trumpet. 








Then some double barrels from one of the vauxhall BTCC cars.





 

[GARDRB]

Would slide throttles be a better DIY build?

[Nominal]

36 minutes ago, GARDRB said:

Would slide throttles be a better DIY build?

I think moving to a diesel where no throttles are necessary would solve the issue.

[GARDRB]

23 minutes ago, Nominal said:

I think moving to a diesel where no throttles are necessary would solve the issue.

I was trying to talk him into Freevalve earlier, then he can do away with cams and throttles

[Roman]

Does freevalve work okay at high rpm though?

 

[GARDRB]

Quote

The rest has to do with the engine's character. "It's a big-bore, big-stroke engine, and it doesn't sound puny like some three-cylinders do," Koenigsegg says. "Imagine a Harley with one more cylinder. That kind of sensation." Despite the 95mm bore and 93.5mm stroke dimensions, the TFG is quite high-revving. Peak power comes at 7500 rpm and redline is set at 8500. "We have a tendency to engineer these rotating parts lighter than anyone else," Koenigsegg explains, "but really focusing on strength at the same time. And if you do that, you can rev higher." The tiny engine also delivers big torque—443 lb-ft from just below 3000 rpm all the way to 7000.

 

That's long stroke and turbo though

[BlownCorona]

a guy i work with was involved with the Primera BTCC cars and they ran double barrels, they potentially offer  performance and flow increase especially at part throttle as the path is more open and much less turbulant?. as you say at WOT, less so as the butterfly becomes very aerodynamic. see the prior CFD and have a look at the pressure areas on the back of the part open butterfly. 

also didn't koiengsegg specifically put the freevalve tech on to increase RPM? something about much much less rotating mass in the valve train

[anglia4]

I had to google the double barrel arrangement, thats a cool looking setup!

[Roman]

Yeah but isnt less flow at part throttle why youre there? Haha 

Also I saw a cool pic of a sectioned race motor that had a cool barrel setup. I think it was a toyota v8 for something. 

[kpr]

easier just to oversize standard throttles,   pretty much nothing to loose if your intake is a bit oversized.  lots to lose if undersized.  if under size intake enough to make gains off the bottom = cork in top end.

[BiTurbo228]

4 hours ago, Roman said:

Yeah but isnt less flow at part throttle why youre there? Haha 

That was my thought. Surely more flow at part throttle just means you have to close the throttle more to restrict the power to the level you need to cruise.

Unless it promotes more efficient combustion or something like that...

[BlownCorona]

space and spec constraints is probably what drove high end racing to them but better flow is not the same as more flow. Ill ask my friend when i see him monday why they were so prevailent in btcc. the only reason i started designing one is cause they look cool which is the only reason i do anything plus it was going to be a great parametric design exercise (type in what size throttle you want and the model shuffles to suit) i dont even give a fuck about performance, speed limit is the same for everyone and im too poor to go racing lol 

[mjrstar]

Not sure if it's an option for you but on my mazda I made a nipple that used an old brake bleed nipple at the high point on the cooling system. Crack it open use some clear hose and dump it into the expansion tank until there is no more bubbles.. it did take a couple of drinks (cooling cycles) from the expansion tank for it to work..

[Roman]

At the moment I am leaning towards the idea of leaving the cap in the standard spot but extending it upwards.
Then I can just jack the back of the car up to help bleed any air out of the radiator I guess.
As much as I hated the electric waterpump in the Echo, it was handy for bleeding the coolant with the motor off.
 

[HumberSS]

Do these k100 throttles on this build solve your height problems?

 

[Roman]

3 minutes ago, HumberSS said:

Do these k100 throttles on this build solve your height problems?

 

Nah those are way too small throttle size, and the ones I've got are e-throttle.
The height will be better once the sump is on, and I can measure how much further I can cut down my engine mounts to lower it.
I should probably just print another sump piece for the area under the crossmember, buuuuttttt printer is broken again. damn thing.
Not a drama though as I've got plenty else to carry on with. 
Wiring is a big job.

[ajg193]

I wonder what sort of amplifiers Toyota used for their VR sensors back in the day.

 

/rambling Barry incoming

My 4K only cranks at 270 rpm, I more than doubled the diameter of the pickup wheel in the distributor and it gets a great signal (apart from some variation in tooth spacing due to questionable machining). I think there would have been little hope of getting a clean cranking signal with factory sized pickups.

 

The distributor is from the VAST era where it would fire automatically if it didn't receive a signal from the ECU. They only had four teeth, no idea how the distributor could possibly predict timing in a reasonable manner. Probably explains why the Hilux is such a turd. I guess Toyota quickly decided the standard four tooth VAST was crap and that's why the Hilux has two VR sensors offset by some angle in the distributor to make the 4 teeth look like 8.

[kpr]

megasquirt lyfe. 

[Roman]

I found somewhere that listed the specs for the factory cams. 
For context, for the Echo, I bought the largest cams available - 264 deg, 9.5mm lift. 
Compared to the factory intake cam on the 2GR is 263 deg, 10.95mm lift. 
So this might run better than expected even with standard cams to begin with. 




 

[Truenotch]

3 hours ago, Roman said:

For context, for the Echo, I bought the largest cams available - 264 deg, 9.5mm lift.
Compared to the factory intake cam on the 2GR is 263 deg, 10.95mm lift. 

Weren't your Echo cams 264° at 1.0mm lift, though? x