Dat sound - ITBs

[arghx7]

The only individual electronic throttlebodies in use for street cars that I can think of are on high end engines like what you find on the S65 engine for for BMW E60 M5 or the 1LR-GUE engine for the Lexus LFA.



What you have here is a set of butterfly valves attached to a common shaft for each bank. Each bank needs its own throttle position sensor and a control method needs to be devised. For BMW, they control the two banks independently and coordinate between the two banks using a high speed data bus.

One of the main advantages is that the throttle valves are placed downstream of the plenum.



Therefore the software does not need to model a large delay/time constant to account for the filling of the manifold as charge air is moving from the airflow meter towards the cylinder.

This issue of time constants is one of the reasons why people run into fueling problems when they install a front mount intercooler on their WRX. The internal airflow model gets messed up.

If you are able to manufacture a part that works, it would still not be easy to control ITBs consistently. Of course you could do some basic lookup table but it would be an uphill climb to make it behave on the street. Who knows how many man hours went into writing Toyota's software for ITB control.

[markmatley]

Originally Posted by arghx7

The only individual electronic throttlebodies in use for street cars that I can think of are on high end engines like what you find on the S65 engine for for BMW E60 M5 or the 1LR-GUE engine for the Lexus LFA.

+1 for the technical engine pedagogy!

[JP]

Originally Posted by Element Tuning

What's holding me back right now is an ECM IO diagram. I couldn't get one yet on the Subaru Technical website so if anyone has access please let me know.

Thanks,
Phil Grabow

Here you go, it's a 3.2mb pic:
http://www.purcellperformance.com/Te.../FT86_full.jpg

[markmatley]

Originally Posted by JP

Here you go, it's a 3.2mb pic:
http://www.purcellperformance.com/Te.../FT86_full.jpg

Bad*ss! Handy to have!

[Esoteric]

Originally Posted by Element Tuning

Thanks.

It's honestly amazing how much ground I've made already with this car and we have the connectors, dual AVCS, and the DBW stuff already worked out. Unlike the IS-F there is much less integration with the FRS/BRZ as far as the CAN systems and the transmission (We are not really working towards the Auto integration yet just the manual).

The CAN bus stuff can be difficult and we've just about got it all dialed for the 08+ STis it will also require work on this car. Until we fully developed the CAN integration on the STi we ran the OEM ecu in parallel so that it could report some of the dash functions like speed and coolant temp. It's possible on the early release of the FRS/BRZ ECU we'll do the same. If demand doesn't materialize then it's going to be hard to justify the engineering costs associated with cracking all this stuff and for many manufacturers it just boils down to dollars and cents.

I don't want abandon the NA guys as I I've discovered hidden power in the dual AVCS systems for the STi and I could likely do the same for these cars. With integration of the Hydramist water/meth system and or race/E85 I think I can get substantial power gains. For high power NA to work with the high compression however we need those direct injectors.

Very good stuff to know. Thanks for the follow up Phil.

I think that a solid tune along with some hot cams will be a tight setup for many folks... Cheap no, but pure? YES.

a few key mods, along with very comprehensive variable valve timing control (built into said tune) could make a very street friendly setup with wicked mid and top-end power. I might have to give you guys a jingle shortly

[Esoteric]

Originally Posted by arghx7

The only individual electronic throttlebodies in use for street cars that I can think of are on high end engines like what you find on the S65 engine for for BMW E60 M5 or the 1LR-GUE engine for the Lexus LFA.

We have worked with some BMW S65/S85 swap stuff in the past. Its doable... Now that its been reverse engineered that is.
The problem I see is not with the implementation from the technical standpoint, its available now... its going to be the cost.
Very hard to justify for this car... the ITBs will be costly, let alone the ECU solution.

If the demand is there, along side the turbos and S/C... It might happen, probably see it from a company like Toda.

[Element Tuning]

Thanks for posting the wiring, not the typical IO but with the other connector images and our knowledge of Subaru electronics its enough to get us going.

I think an ITB setup that sounds sweet really needs the trumpets vs. The barrel type with a standard intake manifold. There are also a lot of compromises with those in terms of cold idle control, ac control, etc. You could work around this with a isc valve thats linked to all throttles for some idle and cold start range.

Given how fast the throttles will be you will need an ems like the Hydra that has maps to specificaly deal with this. It was pretty bad axx on the Miata I tuned.

I was somewhat disappointed in this motor due to the lack of sensation and sound at high rpm so I know where you guys are coming from. I just doesn't have that top end rip you get from the Celicas or VTEC Hondas. When we release the Hydra EMS it will allow you guys to do what you want regardless of it making sense or not. LOL! Initially I'll focus on as much power as i can get on the stock engine using cam tuning, water/meth injection, and or E85. I think i can squeak out 35 and maybe with some bolt ons 10 more.

Thanks
Phil Grabow

[arghx7]

I think we need to temper our expectations on what kind of power can be produced through adjusting cam phasing. The 2GR-FSE had very aggressive cam phasing under WOT from the factory. Other components that affect resonance tuning and noise may provide better gains, especially considering tbat the engine is quiet in stock form.

[Torquemaster]

Hello,

I`m a bit confused about the general problems about running ITBs on the engine. In Germany, it`s absolutly usual to fit ITBs on older cars which may not meet emmision controls higher than EU 2. Cold start and running, enrichments for acceleration aso. is definitly no problem. I´m sure it wouldn´t be a problem at all to fit ITBs to the FA 20 engine just with the low pressure port injection, compr. ratio of 12,5 would be ok with hotter cams. The only problem is the ODB2 which is regulated by law in Germany and I think as well in US and Europe anywhere. Generally, worldwide there are existing estimated 50 different stand-alone ECU systems which are basically able to run an ITB engine, some of the cheapest ECUs will cost less than 1000$. I am a great lover of ITBs and I intend to buy a Toyota GT86 soon. I`ve pretty 25 years experience in race engine building, but unfourtunatly no solution for the OBD-problem in conjunction with ITBs or respectivly, i don`t no stand alone system which contents OBD functions.
I´m worried that it`s almost impossible to use the stock electronic system of the FA 20 engine for integrating ITBs. A special development engineer who was involved in the design of this features has to be found, and even then I´m douting about. The tuning of the high pressure injection system matching to the new requirements of the ITBs (different resonance conditions),together with the port injection, those things along with OBD funtionalities to make work might be a insolvable task.I would abstain from high pressure injection, just make the low pressure port injection work, if this would be possible with OBD, I would start next week

Furthermore, with ITBs in Germany you have to run a new emission test,if successful, it will be 2000 $ if it works.....

Cheers
Udo

[Turbowned]

Well, that's /thread, lol

As someone who has ITB's in his current car, I can say they're a lot of fun and they make a nice conversation piece, but if adding them to a new OBDII car with direct injection is going to cost as much as it sounds like it's going to cost, I'd much rather a turbo or supercharger. Hell, I'd much rather a turbo or supercharger on my current car!

[carbonBLUE]

Originally Posted by Torquemaster

Hello,

I`m a bit confused about the general problems about running ITBs on the engine. In Germany, it`s absolutly usual to fit ITBs on older cars which may not meet emmision controls higher than EU 2. Cold start and running, enrichments for acceleration aso. is definitly no problem. I´m sure it wouldn´t be a problem at all to fit ITBs to the FA 20 engine just with the low pressure port injection, compr. ratio of 12,5 would be ok with hotter cams. The only problem is the ODB2 which is regulated by law in Germany and I think as well in US and Europe anywhere. Generally, worldwide there are existing estimated 50 different stand-alone ECU systems which are basically able to run an ITB engine, some of the cheapest ECUs will cost less than 1000$. I am a great lover of ITBs and I intend to buy a Toyota GT86 soon. I`ve pretty 25 years experience in race engine building, but unfourtunatly no solution for the OBD-problem in conjunction with ITBs or respectivly, i don`t no stand alone system which contents OBD functions.
I´m worried that it`s almost impossible to use the stock electronic system of the FA 20 engine for integrating ITBs. A special development engineer who was involved in the design of this features has to be found, and even then I´m douting about. The tuning of the high pressure injection system matching to the new requirements of the ITBs (different resonance conditions),together with the port injection, those things along with OBD funtionalities to make work might be a insolvable task.I would abstain from high pressure injection, just make the low pressure port injection work, if this would be possible with OBD, I would start next week

Furthermore, with ITBs in Germany you have to run a new emission test,if successful, it will be 2000 $ if it works.....

Cheers
Udo

Originally Posted by Turbowned

Well, that's /thread, lol

As someone who has ITB's in his current car, I can say they're a lot of fun and they make a nice conversation piece, but if adding them to a new OBDII car with direct injection is going to cost as much as it sounds like it's going to cost, I'd much rather a turbo or supercharger. Hell, I'd much rather a turbo or supercharger on my current car!

they already exist lol, like tada said, everything that comes out for the FRS/BRZ/GT86 will be compatible with first year modles, requires buying the part, syncing the throttle bodies with the ecu and doing an ecu flash, not really rocket sience, since toyota already did it themselves

[Turdinator]

Originally Posted by carbonBLUE

they already exist lol, like tada said, everything that comes out for the FRS/BRZ/GT86 will be compatible with first year modles, requires buying the part, syncing the throttle bodies with the ecu and doing an ecu flash, not really rocket sience, since toyota already did it themselves

TGV = Tumble Generating Valve
These aren't ITBs. They are valves that will great tumble to improve combustion efficiency. I also have a feeling these are for the Subaru only version of the FA20 which wont use D4S but just purely direct injection.

I also suspect DIT is for Direct Injection Turbo

[wlfpck]

If I am not mistaken the ft86 is a drive by wire system...

From my understanding, there is a position sensor within the pedal. This determines the amount the throttle body is opened.

The way the throttle controller that is sold now works is by the following:

A voltage is generated when the pedal is depressed. This voltage is unique at each accelerator pedal position. The voltage is translated into how much the throttle body will open.

Given that note:

Would it be possible to basically create ITBs in the same manner as the current drive by wire system? Each TB would then have a sensor that translates the voltage from the accelerator depression into how much it should open.

For instance...
Fully depressed accelerator pedal outputs a voltage of 5V (I made this number up...). Current throttle body opens up 100%. With ITBs, it should also be open 100%.

Half depressed accelerator pedal outputs a voltage of 2.5V. Current throttle body would be open 50%. With ITBs, it should also be open 50%.


Not sure if this is how it works. I'm not really too knowledgeable in this area. So I'm not really sure if I've missed anything.

[Genomaxter]

That is exactly how it would work for us. The only hurdle is metering the airflow. Map sensors would work great for this. Tho, in my opinion a very well made plenum enclosing trumpets would work just as well and only need one throttle body and can still use a maf.

Similar to this except one throttle body where the intake comes into the plenum.

[wlfpck]

Well for mapping the air flow...

Again... this is just from my basic understanding...


A sensor is placed at each ITB. These sensors output a voltage. All of these sensors then feed the output voltage into another sensor which replaces the current MAF. That way, it's almost as if it is tricking the current MAF sensor.

Or... all of the sensors feed a voltage out into a basic circuit board which will have the correct amount of resistors and such so that the output voltage from this "Black Box" would then feed the correct corresponding voltage to where the original MAF sensor would have fed into.

[Genomaxter]

I feel that just leads to unneeded complexity. Also, having a throttle plate in each intake track is a flow restriction in my opinion (but unproven, so leave it as such). One large throttle body with a shaved valve and rod assembly with one flowmeter would be more efficient, easier to tune, build and maintain.

[wlfpck]

No I completely agree that having a larger TB in 1 unit would be easier.


I was simply commenting on easy ways to get ITBs to work. :P

[Genomaxter]

Indeed. It's only a matter of somebody with the knowhow to build and tune this. I would love it for the sound and response. Either way to me.

[serialk11r]

Originally Posted by Genomaxter

I feel that just leads to unneeded complexity. Also, having a throttle plate in each intake track is a flow restriction in my opinion (but unproven, so leave it as such). One large throttle body with a shaved valve and rod assembly with one flowmeter would be more efficient, easier to tune, build and maintain.

I don't think it's a flow restriction, but I agree with the rest. At first, ITBs sound like a great idea, until you realize that a single throttle body with a well designed intake plenum/manifold is pretty much just as good for performance and eliminates many of the potential problems with ITBs. Unless you don't want to run filters, which for a street car is a retarded idea. I guess the issue with a boxer engine is that modifying the intake manifold isn't so straightforward since there are 2 cylinder banks...

Just on a side nerd note, ITBs at very low load with a "small" intake cam can have a miniscule part load efficiency benefit

Also, ditching the direct injectors is a pretty stupid idea for those talking about that.

[Torquemaster]

The wicked sound of the ITBs is not that reason for me to prefer. Throttle response is incomparable to every other system no matter if turbo or 4 runners into a plenum with one central big throttle. The engine responses like an explosion on every tiny pedal movement. Next advantage: With ITBs you can fit race cams with a duration of more than 300°/1mm lift without any idling issues or part throttle hopping. Overlapping valve lift might be more as 4 mm in TDC, no chance for a single throttle to get a smooth idling. Of course: if someone could integrate the stock ECU functions together with ITBs, the variable camshaft adjustment may retard the overlapping to a compatible overlapping lift of about 1mm or lessfor idling. But- I don`t see the specialist who has this skills however as stated before. If there wouldn`t be any emission tests or OBD-troubles,it`s sur as hell that the engine would run with ITBs and just a low pressure port injection. Additional stated: When using ITBs, itwould never work with a map-sensor. Behind the throttles low pressure is extremly shaking on part throttle or idling, completly different conditions to a plenum. ITBs have to be managed by "Alpha-N" management, the engine load is mapped by throttle angles, together with the rpm-signal is it the main figure for the mapping procedure.
Something off-topic from my today impressions: I rode firstly the Toyota GT 86,and - sorry, but tbh I was really disappointed about the engine especially under 5000 rpm it pulls really poor.It felt like dead, the car was almost brand new and had about 1800 km ( 1000+miles). When revving higher, it feels more vital, but the range to the redline feels really stressful anyway. What a pity for this fine handling, I think the gearbox ratios are much too long for this relativly heavy car with small displacement. I think about increasing the displacement up to 2,4 l with bigger sleeves and a stroker crank, I don`t like turbos (but thats a matter of taste) Bigger sleeves are in progress at Darton (90 mms with standard stroke means about 2,2 L).A stroker crank is not yet anywhere offered to my knowledge.
I know it sounds crazy, big expense, but this mods would show an engine behaviour whats expected by many of us i guess. Maybe 260 real bhp at 7000, 280 Nm (205 lbf) at 5000 ( with ITBs, 2,4 L, all mods) And trottle response like hell......but i know your answer: Go to turbo or supercharging

tired now, good night Germany

Cheers

Udo

[Genomaxter]

Drive a broken in car. I have 9200miles on my car and the pull from 3k on is much better than new.

[Turdinator]

Hypothetically, if you overcame the issues drive by wire presents, could you run a manifold over the ITBs and ducting utilising the factory MAF? If this were doable you could still use something like Ecutek to manage the motor as it seems to be the only thing that will run the D4S as its meant to be...