Single throttle body or keep ITB's?

[greddytrustGTR]

so im going single turbo this winter, and i've collected a bunch of parts, and now im at the intake manifold, i currently have the stock intake manifold that has had the runners port matched, but i read that a single throttle body manifold with a 85mm+ throttle body makes monster power on a single turbo? what are your thoughts and know any brands of single throttle body manifolds?

[gtrjon]

+1 into know more

[Super_Dude]

What single are you going with? I'm in the same boat as you. I think the itb's work good but a lot people are switching to newer style manifolds and single throttles and are actually finding better response and power (hi octane r34)

Overall, I think the manifold and throttle bodies should be one of the last mods you do as there are better gains with cheaper parts.

[cortexx]

The concept behind the multiple throttle bodies on the RB engine is that the throttle butterflies are as close to the intake valves as possible for instant throttle response. Having a single throttle body the other side of the intake plenum means there is a time delay before the opening of the butterfly is felt at the intake valves, although it is tiny it makes a difference on a race track.

Its alot more expensive and complicated to make a multiple throttle body setup in comparison to a large single but obviously nissan engineers thought it made enough difference to do it.

As an example , on a triumph spitfire i used to have you can run a single large carb on a 4-1 intake manifold or 2 side draught twin choke weber or dellorto carbs , the instant response of the mutichoke setup was something you could feel.

I would stick with multi-TB for track racing or street and maybe go single turbo , single TB for drag racing.

[Dragon Humper]

ITB's and MAF can be an issue because they are a little leaky when they get old. MAP based engine control doesn't give a rat's petoot how many leaks you have.

As far as response goes, I don't think you will notice a diff. between multi and single TB, FI and a turbo is mellenia ahead of carbs and really you can't compare one to the other.


On thing that can make a big diff. is cyl to cyl ballancing, which we all know the stock manni is horrible at once you get really up there in power. That is why I wouldn't waste my time with an aftermarket manni that still uses the ITB's to correct that imballance, for the same money + the TB, you can simplify things greatly. If you have a line on a manni for a decent price, have at her, but don't go blowing $1800 on stuff you don't need if you are under 800hp.



I am currently at the 700hp mark and the ITB's and stock manni are working just fine, with a little more fuel trim for #6.




Jon.

[greddytrustGTR]

ok i was planning to keep it safely around the 700whp mark, but i il probably slap on the new turbo and decide if i really need the new intake manifold. was just looking for some information and see if anyone was running one and what was the difference before and after.

[Oakville]

a friend of mine is running in that powerband but on R34 N1s. He opted for the JUN intake plenum with STB, from what he told me that plenum is designed to allow the most possible air to go to 6 so nothings starved.

[Super_Dude]

The issue with the stock one is to much air gets to six

[jdms13rhd]

The concept behind the multiple throttle bodies on the RB engine is that the throttle butterflies are as close to the intake valves as possible for instant throttle response. Having a single throttle body the other side of the intake plenum means there is a time delay before the opening of the butterfly is felt at the intake valves, although it is tiny it makes a difference on a race track.

Its alot more expensive and complicated to make a multiple throttle body setup in comparison to a large single but obviously nissan engineers thought it made enough difference to do it.

As an example , on a triumph spitfire i used to have you can run a single large carb on a 4-1 intake manifold or 2 side draught twin choke weber or dellorto carbs , the instant response of the mutichoke setup was something you could feel.

I would stick with multi-TB for track racing or street and maybe go single turbo , single TB for drag racing.

I agree

Nothing beats the rb26 response and sound! Keep itb's. Get your 700hp and then upgrade if you wish. The intake setup is alot of money for little difference in your powerband. Its the last thing on my list for rb26

[4jo3]

i think it all depends on what your after ... if you want throttle response stay individual throttle body. how big of turbo are you going? but i have a feeling since your going big single, you may want to swap to single individual, i know over in AUS hypertune plenum is the one to get. (mainly because of bang for buck)

on a side note you can modify your individual throttle bodies. this is what i chose to do. but i have a matched greddy plenum and lower intake manifold. im still running my upgraded twins but they should be maxed out this season and im contemplating running a really big single or top mount twins. im after response.

[NismoS-tune]

I'd vote for single ITB. Less leak possibilities, cleaner install, less weight. Check out RIPS!

[Dragon Humper]

Oh yea, the second it looks like I have to tear the ITB's apart to fix a bunch of leaks it's out of there and in the garbage. ITB's are only a benefit when you are non-turbo, they don't make a lick of difference once you start blowing the air in. The only reason Nissan used them was really a marketing thing. A $50,000 car should have a fancy intake manifold setup, shouldn't it? That's also the reason the GTiR had them but no other SR20 powered vehicle had them, marketing.

Response is a non-issue, you can fill up a 5L inlet plenum really EFing fast with only 2psi of boost, especially when you are sporting 3" charge pipes and a larger intercooler.




Jon.

[greddytrustGTR]

Haha nice, actually I was thinking of RIPS again, They are making me an exhaust manifold as we speak haha, I'll probably just have them make me an intake manifold too

[cortexx]

That doesnt make sence , why would nissan over engineer something to increase percieved value without an actual benefit .

Also check out the setup on the hakosaka , did they over complicate that setup for the same reason ? basically a dedicated race car.

Car manufacturers are all about decreasing production costs while selling at a price that makes them as much cash as possible.

The mines tuning company stated they kept ITB on their RB26 powered cars for the best throttle response , there is a review on u-tube somewhere where they compare a bunch of cars offered for test from japanese tuning companies and independents.

As far as carbs vs turbos go , it makes no difference the physics on the intake are essentially the same , the TB nearest the intake valves on the head provides the fastest throttle response. In fact when you first open up the throttle from nothing there is no to little boost until the turbos spool up , essentially providing no benefit over a carb anyways.

The only reason Nissan used them was really a marketing thing. A $50,000 car should have a fancy intake manifold setup, shouldn't it?

[hozer]

Single TB if your going single turbo. Nothing but problems with trying to make the single work with stock setups. Have a large single turbo and a single TB and the response is killer, gets tracked all the time.

I have no science or "facts" to give you but I know from first hand experience that it's a huge pita running a single turbo and itb. Convert all at once and save headache