ITBs finally for sale

[TylerLieberman]

Jeez.

This + I/H/E + tune... that's a lot of money just to make 200whp on pump gas.

[StraightOuttaCanadaEh]

Originally Posted by nikitopo

A 15 hp peak power increase (also speculating) would be a very good gain for a NA car. It does not give the gains of a SC, but you don't put either a 60lbs. additional weight in your engine bay.

but the price!

[nikitopo]

Originally Posted by StraightOuttaCanadaEh

but the price!

If you want to stay NA, then you have to pay. I 've paid already the cost of 2 superchargers and now I'm going for the 3rd.

[Opie]

Why not just install the red top from the 2017/2018?

[mav1178]

Originally Posted by Opie

Why not just install the red top from the 2017/2018?

Because that doesn't have ITBs.

[gtengr]

Originally Posted by guybo

The distance from the MAF to the ITB's is too far to make much difference IMHO. Air is measured at the MAF and the time it takes for the air to travel to the throttle plates is where much of the response lag comes from.

The lag is in the time for newly demanded air at the throttle blade to reach the cylinder. The distance from MAF to ITB on the 86 would be less than it was on my old M3.

[guybo]

Those aren't independent TB's anyway. There's 1 MAF and the throttles all work at the same time, not independently. They are 4 separate throttle plates. The MAF to TB distance is a real thing and affects throttle response. I'm sure it'd be better than stock since there's less plenum volume in vacuum, but it'd take some serious engineering to make true ITB's and a custom tuning solution like MOTEC and 4 MAF's to make it so each TB can independently work.

If anyone does this mod, I want to see numbers.

[x808drifter]

Originally Posted by guybo

Those aren't ITB's anyway. There's 1 MAF and the throttles all work at the same time, not independently. They are 4 separate throttle plates. The MAF to TB distance is a real thing and affects throttle response. I'm sure it'd be better than stock since there's less plenum volume in vacuum, but it'd take some serious engineering to make true ITB's and a custom tuning solution like MOTEC and 4 MAF's to make it so each TB can independently work.

If anyone does this mod, I want to see numbers.

I believe IRTB would be a more correct term.

Individual
Runner
Throttle
Body(bodies)

[gtengr]

Originally Posted by guybo

Those aren't independent TB's anyway. There's 1 MAF and the throttles all work at the same time, not independently. They are 4 separate throttle plates. The MAF to TB distance is a real thing and affects throttle response. I'm sure it'd be better than stock since there's less plenum volume in vacuum, but it'd take some serious engineering to make true ITB's and a custom tuning solution like MOTEC and 4 MAF's to make it so each TB can independently work.

ITB = individual throttle bodies, not independent. I'm not aware of any car that runs individual cylinder MAF sensors and throttles that operate independently of one another. It's possible, but I think it's safe to say that's not what is meant by ITB's in the sub-$150k car realm. Do you know of any examples?

[mav1178]

Originally Posted by guybo

Those aren't independent TB's anyway. There's 1 MAF and the throttles all work at the same time, not independently.

Originally Posted by gtengr

ITB = individual throttle bodies, not independent. I'm not aware of any car that runs individual cylinder MAF sensors and throttles that operate independently of one another. It's possible, but I think it's safe to say that's not what is meant by ITB's in the sub-$150k car realm. Do you know of any examples?

A good example of this in action is the RB26DETT found in R32-34 GT-R. 3 sets of 2 throttle assemblies, 6 individual throttle bodies via 2 MAF (each MAF feeding a turbo)

-alex

[gtengr]

Originally Posted by mav1178

A good example of this in action is the RB26DETT found in R32-34 GT-R. 3 sets of 2 throttle assemblies, 6 individual throttle bodies via 2 MAF (each MAF feeding a turbo)

-alex

That's different. Those throttles are synced, not independent. And I was specific about a MAF sensor per cylinder because the other poster specifically said you'd need 4 MAFs to make it run right on an FA20. I know it's common to run split MAF sensors in situations where you have 2 intakes (two turbos, V8 with an intake feed per cylinder bank, etc). The point was that running a single MAF sensor doesn't represent a hindrance to feeding 4 ITBs, and that having synced individual throttles is the standard way of running ITBs. OEM's do it all the time.

[mav1178]

Originally Posted by gtengr

That's different. Those throttles are synced, not independent. And I was specific about a MAF sensor per cylinder because the other poster specifically said you'd need 4 MAFs to make it run right on an FA20. I know it's common to run split MAF sensors in situations where you have 2 intakes (two turbos, V8 with an intake feed per cylinder bank, etc). The point was that running a single MAF sensor doesn't represent a hindrance to feeding 4 ITBs, and that having synced individual throttles is the standard way of running ITBs. OEM's do it all the time.

So how can an old school ITB setup be truly independent? All cars with ITB only have one cable from the gas pedal, so they are all synced. Same with the Greddy unit launching, same with the SARD unit launching.

Once the air is metered properly, ITBs work the best when the runners feeding air to them have equal flow coming in. That's the most important part.

[gtengr]

Originally Posted by mav1178

So how can an old school ITB setup be truly independent? All cars with ITB only have one cable from the gas pedal, so they are all synced. Same with the Greddy unit launching, same with the SARD unit launching.

Now you understand why I was asking the other poster for examples of cars that use these independent throttles, because I haven't heard of it either. My post was very specific when you go back and read it: "I'm not aware of any car that runs individual cylinder MAF sensors and throttles that operate independently of one another."

[mav1178]

Originally Posted by gtengr

Now you understand why I was asking the other poster for examples of cars that use these independent throttles, because I haven't heard of it either. My post was very specific when you go back and read it: "I'm not aware of any car that runs individual cylinder MAF sensors and throttles that operate independently of one another."

I know, but I quoted yours because this type of throttle setup in a practical application usually involves 1) 1 or 2 MAF depending on the intake setup, and 2) individual throttle bodies that are controlled via a single actuator/cable assembly.

We're talking about the same thing. In practice, ITB setups are NEVER independent throttle bodies unless you are running engine management on a cylinder by cylinder basis.