1JZGTTE VVTi. Twin Throttle Bodies

[wizza_101]

Im contemplating building a Twin turbo, Twin throttle body 1JZ VVTi.

heres the catch though.
instead of feeding the charged from two turbos into two throttle bodies and then on into the 6 cylinders, im thinking of doing the cylinders in two seperate banks.

eg two turbos. each feeding one throttle body each but each throttle body feeding only three cylinders. each also going through their own water to air intercooler. (to further bring boost on sooner)

advantages of this being is quicker onset of boost.
can be tuned quite easily with an aftermarket computer.
can still run single fuel rail but with a higher pressure to ensure consistency between injectors.
also opening up the bonnet to see that the best of everything came in pairs.
would look fair sweet i reackon.


can anyone else think of things that need to be done or if anyone else has done this on their 1/2JZ or any straight 6 for that matter.


BTW this is going into my RA28.

cheers
Wizza

[wagonist]

Look into some info about VG30DETT that's in the Nissan 300ZX.
It had twin turbos, intercoolers, throttle bodies on a V6.
I believed that there was a single wastegate though to ensure that both banks had the same boost.

I really can't see how this would improve anything though?
On a V6 where you've got both items (ie exhaust & intake) on both sides of the engine bay the plumbing can be improved (though the intake was a pain) & most twin turbos will feed into a single intercooler into a single throttle body, etc.

I just see a mass of piping throughout your engine bay with very little (if any) gain.

The point of having parallel turbos is so that they can be downsized, improving their ability to spool up & hence create boost earlier.

Though improvements can be made beyond that. ie the VVTi single turbo 1JZ produces more boost lower down than the earlier twin turbo versions, and then sustains it.

[jonathan yee]

are the turbos' going to be spooled "sequentially" or both at the same time?

if it's the later then you wont get any benefit cuase it'll be like running 2 3cyl turbo engines(very generalized comment)

only way to run twin turbo's for quick spool and monster top end is something along the lines of WTFauto's sequential system's, been done to a 1M and 2J.

[jimmmayyy]

would be a fair waste of time i reckon. doubling the cost for absolutely zero gain.

VVTi 1j has bucketloads of torque from lowdown with the single..and separating the flow through two throttles? why? its not like the standard throttle is any restriction anyway.

[wizza_101]

the idea came from the latest BMW 3.0 L6 that has achieved full boost at 1300RPM. OMG!!!
and still has a fair amount of power of 385hp. which is kinda cool.

cheers
wizza

[-GT-]

Which, like the vvti 1j, will be from the significant amount of cam timing variation over the rev range rather than twin throttles.

[Mr_Flawless]

The other difficuly is going to be balancing out the banks, by spliting the engine into 2 3cylinder banks, you have to start focusing on major tune work, balanced throttle bodys, a good ecu and for that matter a tune,
u also have to watch mixtures and combustion temeratures for each bank. a 300ZX runs twinturbos with there own wastegates, and in factory form they crossfeed there air supply ie: the turbo on the right bank of the
engine feeds the throttle body for the left bank and the turbo on the left bank feeds the throttle for the right bank, this inturn helps the engine balance out so one bank and its turbo doesnt overtake the other. hence why
300zx works better with twin coolers rather than others such as the greddy front mount which changes the feeds and ruins the balance. bank balancing is tricky bussiness.

By the sounds of it u want some more grunt down low? if this is the case have a custom plenum made with longer runners and ram tubes. this will provide more grunt down low and if combined with a good single turbo,
set up properly with a good tune, it should prove itself to be a very torquey setup and will probbably be more cost effective. another way of achiving a better response on a single turbo setup is to run an external wastgate
and plumb it back properly into the exhaust to achive better flow and a extractor like effect. this helps bring the boost on quicker, and pluming the bov back into the intake at the right angle and entry point will help keep
the turbo spooling between gear changes therefore reducing lag between shifts.

sorry about the long post, just some food for thought

[wizza_101]

sorry about the long post, just some food for thought

nah your right. keep it coming. that does actually sound like a fair sweet way to get some more lower down grunt.

any ideas who makes "off the shelf" plenum chambers?

that said ive gotta finish my suspension before i go on the hunt for more power

[Mr_Flawless]

no idea for of the shelf items but if its top end grunt speak to hypertune if its low to midrange grunt do some reasearch into plenum design, if u want im happy to assist
and u can get it fabricated
but a good example of a torquey engine is a SR20 from an s13, its the best one and it has the most torque due to a good plenum design, and incredibly good port work/shape from the factory. let me know if u want some help with the setup.

[wizza_101]

i think some RnD will be in order then, cause another family member said
"Horsepower sells cars, Torque wins the race" - cant remember

PM Sent - Mr Flawless

[Mr_Flawless]

i think some RnD will be in order then, cause another family member said
"Horsepower sells cars, Torque wins the race" - cant remember

PM Sent - Mr Flawless

Its "Talk sells Cars, Horsepower wins races" the saying itself is a total rub'n'tug because it all depends on what the car is being used for. lol but ur enthusiastic thats an A+ in my books

[Draven]

No offence intended... but seriously, doing a twin throttle body mod to a vvti 1j is possibly the worst bang for buck mod you could think of.

There's just no point wasting your money on it. Buying a better turbo, intercooler, ecu, tighter piping, get trumpets in the plenum, work the cams for what you're after... all these things will give you a hell of a lot more performance than twin TBs on an I6 FI setup.

Bear in mind the BMW engine has 10+ years of R&D (and probably 10x more $$$) spent on it, so your 1j is just not quite going to cut it in that league.

Proper sized turbo is def the best thing you can do for best performance/cost/response

[RONA]

BMW is also 0.5L bigger in capacity which kinda helps with response.

[wizza_101]

alright. i see your reasoning.

theres there bin.
currently walking over to the bin.
releasing the idea from my.
watching it fall into the bin.
putting the bin out on monday night.
watching rubbish collector come and empty bin.
watching rubbish collector drive away and off to the tip.

Idea GONE!
lol.

thanks guys.
probably saved me a furtune too.
but hey it was an idea.

cheers
wizza