toyota 1gr 76mm throttlr body

[s2d4]

Originally Posted by Crazy Drew

Wow, there's so much misinformation and speculation in this thead it's amazing. I was going to post something informative about ITB's and fuel injection theory since a lot of this is being blown out of proportion but my words would just be wasted in the idiocracy that this forum has brought about. Thanks for the entertaining name calling and bashing. I'll go back to my garage and have a good laugh.

Might I suggest people do some reading on Helmholtz Resonance before assuming that short runners make power. Understand the mass flow pulses in a single TB rather than ITB's and the difference between drivability problems and a properly tuned car. It's not 1990, we're past Alpha-N, and we definitely don't need something as complicated as 4 actuators for ITB's.

Feel free to post please, I don't mind learning from people that actually know something.

Sent from my Galaxy Nexus using Tapatalk

[fooddude]

@Crazy Drew: Would adapting something like TWM's ITB's (made for a Honda B series) with a custom made runner piped adapter work on the FA, with some sort of additional adapter to convert its' old cable throttle to the newer FA electronic TB motor (or maybe re-use the oem FA electronic TB motor to it)? Or would the fuel delivery be totally out of place and hard to work out?

Probably more work than it's worth and most likely better to wait for a proper ITB actually made for it.

[fooddude]

Originally Posted by s2d4

Non-turbo ITB 1988.

?? ..looks like an ordinary old car with a single TB to me lol.


Now here's some ITB's on a similar subaru boxer engine
Roller Barrel ITBs for subaru boxers
[ame="https://www.youtube.com/watch?v=ctyBOEk3L9Q"]Subaru ITB - YouTube[/ame]

[fooddude]

These guys can make custom ITBs for the FA:
http://haywardperformance.com

Maybe these guys can make some too:
http://www.borlainduction.com


http://www.tomei-p.co.jp/inf/pdf/112_ae_Letter.pdf

More info on Roller Barrel ITBs
http://www.zetecinside.com/xr2/archi.../dec2008.shtml
http://www.tristatetuners.com/forum/...ad.php?t=23730
http://forums.nasioc.com/forums/show....php?t=1175829

[mike the snake]

These ITB's are intersting. They can be used for any application with custom manifolds. IIRC they were priced a lot better than the other alternatives.

http://www.extrudabody.com/servlet/StoreFront

[fooddude]

I wonder who makes these and when they'll be available...they appear to have the non-cabled electronic controlled TB motors too. Looks like a simple install (aside from the complex tuning/syncing with the ecu though, lol)

[Malt]

Originally Posted by fooddude

I wonder who makes these and when they'll be available...they appear to have the non-cabled electronic controlled TB motors too. Looks like a simple install (aside from the complex tuning/syncing with the ecu though, lol)

Those are tumble generator valves, not throttle bodies.

[fooddude]

Reading this old thread..it seems it will be very difficult to have ITBs running normally on the FA.
http://www.ft86club.com/forums/showt...?t=7939&page=4

Really curious as to who made those roll barrel ITBs on the blue subie in that 6 year old video (is it domestic/US builder?)... if anyone, I bet they could sort/make ITBs for the FA. (if not, then JUN or Tomei...but those would most likely be out of reach, too expensive, or not available to regular US consumers).

[mike the snake]

It might be easier to convert to downdraft carbs. Carbs actually can make slightly more power than ITB's.

I had 50mm PMO carbs on my Porsche race car, and it was insane. At 13-1 my old engine was similar to our new engines. Throttle response was beyond instantaneous.

Originally Posted by fooddude

Reading this old thread..it seems it will be very difficult to have ITBs running normally on the FA.
http://www.ft86club.com/forums/showt...?t=7939&page=4

[fooddude]

Anyone know who made these?
[ame="https://www.youtube.com/watch?v=ctyBOEk3L9Q"]Subaru ITB - YouTube[/ame]

[stugray]

Originally Posted by mike the snake

It might be easier to convert to downdraft carbs. Carbs actually can make slightly more power than ITB's.

I had 50mm PMO carbs on my Porsche race car, and it was insane. At 13-1 my old engine was similar to our new engines. Throttle response was beyond instantaneous.

Funny I was going to comment on how my race 914 has Weber IDFs, then you show that picture (you beat me to it).

A couple of guys in my racing league have taken the stock TB from the 914-4 D-jetronic system, and put 4 of them on a 4-cyl with megasquirt.
They also run E85.
I am guessing they are getting ~130hp at the wheels from a car that had 86hp at the crank in stock form.

[s2d4]

Originally Posted by fooddude

?? ..looks like an ordinary old car with a single TB to me lol.

Definitely not single TB and is NA.

[wu_dot_com]

Originally Posted by Crazy Drew

Wow, there's so much misinformation and speculation in this thead it's amazing. I was going to post something informative about ITB's and fuel injection theory since a lot of this is being blown out of proportion but my words would just be wasted in the idiocracy that this forum has brought about. Thanks for the entertaining name calling and bashing. I'll go back to my garage and have a good laugh.

Might I suggest people do some reading on Helmholtz Resonance before assuming that short runners make power. Understand the mass flow pulses in a single TB rather than ITB's and the difference between drivability problems and a properly tuned car. It's not 1990, we're past Alpha-N, and we definitely don't need something as complicated as 4 actuators for ITB's.

im curious as to your insight as to how to properly implement ITB for this car?

looking at the two existing designs, having an inline ITB with long intake runner just dont make much sense in the performance aspect as an optimization design.

having 2+2 ITB with mechanical linkage that actuated by a common motor does eliminate the long intake runner issue, but also dont make an optimize design. since 1. parts have to be in close tolerance to one another which drives up the cost. and 2 you lose the ability to individually adjust the TBs (this is a weaker point because the existing ECU was probably never program to take cam position and knock reading for individual throttle position adjustment).

ideally a perfect ITB package that would work great would incorporate a plenum with single MAF or individual MAF, single / individual O2, 4 electronic throttle with controls. the controller can be one integrated circuit that does it all. d each electronic throttle body can be mass produce with much cheaper per unit cost. The control programming for a single O2 application is much simpler because the controller would only have to worry about synchronizing each TBs.


i would like to pick your brain as to the work around of alpha N mode. other than an alpha N tune, or compensated MAF with plenum or individual MAF that feeds the sum of MAF readings to the existing ECU, what are some other remedy that are currently being use for correct fuel metering?

[Crazy Drew]

Originally Posted by s2d4

Feel free to post please, I don't mind learning from people that actually know something.

Sent from my Galaxy Nexus using Tapatalk

Where would you like to start? I could honestly post pages worth of info on this stuff but most people won't want to read a giant wall of text. If people are genuinely interested I'll be glad to share the knowledge that I have. I am by no means a motorsports "engineer" however I have worked for several race teams in the past and have experience in development of intake manifolds (single throttle and ITB), plenums and getting engines to perform better than OEM in specific (restricted) applications. I no longer do this professionally as I needed a consistent paycheck.

There's a cubic crapload of information available on individual throttles dating back almost 60 years, as these are all just evolutions of the Weber (heck, even before Weber) downdraft and sidedraft carbs. Even though we're talking about fuel injection rather than carbed the information is still valid. They still perform the same task, injected is just better controlled for improved response, fuel consumption and drivability.

Originally Posted by fooddude

@Crazy Drew: Would adapting something like TWM's ITB's (made for a Honda B series) with a custom made runner piped adapter work on the FA, with some sort of additional adapter to convert its' old cable throttle to the newer FA electronic TB motor (or maybe re-use the oem FA electronic TB motor to it)? Or would the fuel delivery be totally out of place and hard to work out?

Probably more work than it's worth and most likely better to wait for a proper ITB actually made for it.

If I were to design an ITB setup for the FA motor I would utilize throttle bodies from anyone who manufactured a Weber IDA style throttle larger than 52mm. The ones specifically from TWM for the B series would be a bad choice because the throttle body is integrated into the intake manifold. If you utilized one that was flanged you essentially just need some head flanges, some throttle body flanges and a skilled fabricator to make tubes that adapt from the oval ports to the round throttle body. Honestly, the white car referenced in this thread has it going on for the full setup.



In order to keep from flooding this thread with too much info all at once I'll post a few basics. If anything needs further explanation or anyone would like to discuss it feel free to ask.


Drivability - In certain applications, such as engines with large overlap camshafts ITB's will improve idle quality, comfort in the car as a result of that, and improved low rpm characteristics. This is because on ITB's it's impossible for one cylinder to steal the air from another while reversion in the port is occurring.

"Short runners make horsepower" - While this can be true there's a whole lot more going on with it than that. Air behaves like a sprung mass. Helmholtz resonance does a fantastic job of explaining how air moves in a closed end tube. Not going too much into detail but at certain frequencies ((RPM/2)/60) the entire mass of air in the runner will be moving towards the intake valve while it's open. This is without the piston pulling it but rather the speed at which the pressure wave travels back and forth in the intake. Longer runners have a larger amount of mass to push the air into the cylinder, or inhibit the air from efficiently filling the combustion chamber. These are lower level "orders" think of them like octives. An "A" note is an "A" note regardless of what octive it occurs in. If the length and diameter are tuned right you can fill the cylinder with a huge amount of air with a lower level harmonic than a higher level (short runners) because of the large mass pushed by the pressure wave.

Driveability problems - Not really sure where to start on this. 99.9% of auto enthusiasts aren't tuners. This isn't really a problem but just how the nature of the beast is. If we all knew how to tune our engines there'd be a bunch of people out of a job and you could constantly tweak and tune your maps to have the best drivability possible. I'd say the percentage of power tuners vs engine tuners is really about the same. 99.99% of tuners only tune for peak power numbers at WOT and don't do much if anything with the lower throttle ranges. I have tuned a few cars in my day and honestly, my greatest accomplishment took hundreds of hours tuning to get right. But it started first crank, every time, got 43mpg out of a v6 and ran very low 12's in an integra with an unopened motor and without forced induction. Tuning like this though is insanely expensive and the majority of people would balk at a quote to tune a car in the 4 figure range. The biggest problem with the tuning on ITB's is the lack of a good MAP signal. Since there is no plenum there's no good single source for vacuum and you wind up with a gigantic mess of vacuum lines, accumulators and T's to get something decent to reference engine load. If you could get a good MAP signal and tune using speed density there's no reason you couldn't run ITB's with a factory ECU in the twins. The ECU in these cars is amazingly fast and more than capable of what's needed from it in almost any application (except "driving" stuff like low impedance injectors)

Single vs individual TB sizing - Individual throttles need to be massive in comparison with a single because of the individual throttle's lack of plenum between the throttle blade and the intake valve. ITB's benefit in having "infinite" plenum outside of the velocity stacks, assuming an enclosed plenum isn't added for noise control/boost. Single throttle bodies only need to be sized large enough to limit the pressure drop across the butterfly going into the plenum. In general you want the plenum to be as large as possible without losing drivability. Drivability is lost when the plenum gets so large the throttle body has a hard time limiting the mass flow between the TB and the intake valves and the car becomes "numb". A good general rule of thumb when designing intakes is to start with a plenum 2-3 times larger than the displacement of the engine for maximum power. Since single TB's have a large plenum that damps out the intake pulses traveling through the intake the single TB only needs to be large enough to supply 2-3 cylinders worth of air at a time. Any larger and you're getting difficult to control at lower throttle percentages since huge changes in open area happen at relatively low angle changes. There's also only about 2 intake valves open at a time, and even this overlap of two being open is very brief in the engine cycle. If I knew the valve events of the FA20 camshafts I could calculate it out but realistically you're only talking a handful of degrees in crankshaft rotation.


I'm sure I've made this either crystal clear or as murky as mud. As I stated, if you want to know more or anything needs clarification please feel free to post.