How to build ITBs

[StegaDragon]

I'm pretty sure he means with a regular intake manifold set up, there's a limit to how short the runner can be due to the distance between cylinders

SC10N driver

[2much]

Originally Posted by GSpeed

Yup. Motec is popular for a reason, though... It's pretty powerful stuff and really isn't a bad price for the capabilities it's got.



I mean, no one's disputing it's expensive, but it's more than a fuel management system, it's basically everything but ABS. Traction control, launch control, etc. can all be handled. Especially with throttle-by-wire, you can do fun stuff like throttle-controlled traction control, etc.

I certainly did not mean to add anything meaningful to this discussion, just could help myself with the FATF quote

[Calum]

Originally Posted by celek

why do you say that can not be made short enough?

If you make the plenum bigger to get the runners shorter, you could sacrifice throttle response. But technically speaking it is possible.

[GSpeed]

Originally Posted by 2much

I certainly did not mean to add anything meaningful to this discussion, just could help myself with the FATF quote

Wow, that was a pretty obscure quote. Nicely done. Slipped right by me.

Guess I've been quoting too much Talladega Nights.

Jake

[celek]

Originally Posted by Calum

If you make the plenum bigger to get the runners shorter, you could sacrifice throttle response. But technically speaking it is possible.

What if its set up like a LFA engine? "google" now?

[200hp/tonne]

With Ecutek, will you keep the MAF style of tuning? Or will you switch to Speed-Density like some FI people? For MAF you can make a light duty CF or Aluminum plenum like the BMW M cars and still be mechanically compatible with the intake. Also, making a MAF tune should be easier

[celek]

Originally Posted by 200hp/tonne

With Ecutek, will you keep the MAF style of tuning? Or will you switch to Speed-Density like some FI people? For MAF you can make a light duty CF or Aluminum plenum like the BMW M cars and still be mechanically compatible with the intake. Also, making a MAF tune should be easier

Which is why I referenced the LFA's engine

[StegaDragon]

Again the issue is distance between banks, the LFA is a V8 and the intake ports are relatively close together compared to boxer engines, while individual TB would not have an issue, running a single intake manifold limits how short the runner can be without running a rather large intake plenum

SC10N driver

[StegaDragon]

Or maybe do two intake manifolds

SC10N driver

[200hp/tonne]

Throttle bodies would still be at the heads, the plenum would just provide filtered atmospheric pressure air to the runners through the MAF, and can be made from very thin gauge aluminum or CF. This is to avoid sucking in air from the engine bay

[Spartarus]

Originally Posted by StegaDragon

Again the issue is distance between banks, the LFA is a V8 and the intake ports are relatively close together compared to boxer engines, while individual TB would not have an issue, running a single intake manifold limits how short the runner can be without running a rather large intake plenum

SC10N driver

The LFA is a v10, not 8, and the design is not original.

BMW introduced it to mass production on the S62 engine for the E39 M5 12 years earlier. Yes, it can work.

The concept uses ITB's to compensate for the throttle response issues inherent in a large plenum.

That's the only practical way to use MAF with ITB.

I have never seen MAP-based speed-density work right with ITB's. You lose all your vacuum above about 40% throttle.

The smoothest running ITB setups (without a plenum) I've seen and worked nearby are all on a high-resolution alpha-N map where the primary inputs for fueling are throttle position and RPM. Significant corrections include ambient temp/pressure, wideband closed-loop at low throttle settings, and very thorough tip-in and overrun corrections.

Getting them to idle is harder than tuning them to run.

[StegaDragon]

Woop confused it with the IS-F

SC10N driver

[200hp/tonne]

http://www.hipermath.com/engines/throttle_body_size

[celek]

Originally Posted by StegaDragon

Again the issue is distance between banks, the LFA is a V8 and the intake ports are relatively close together compared to boxer engines, while individual TB would not have an issue, running a single intake manifold limits how short the runner can be without running a rather large intake plenum

SC10N driver

exactly a very large plenum, what else would go in the middle of the engine