toyota 1gr 76mm throttlr body

[fooddude]

Originally Posted by zooki

I would think that ITB's would behave a little differently that one large throttle body. It's easier to start and stop a smaller volume of air than an entire plenum full of air. Peak horsepower may be similar, but drivability should be a lot better with ITB's.

I get your point..but I find that very hard to believe. 1 TB will be much easier to make a car more drivable and have better drivability, from a single maf sensor standpoint. ITB's are very difficult to tune and make drivable - the exact reason 99% of manufactured cars have 1 TB and also the exact reason why you haven't seen a single video of ITB's working on a BRZ/FRS yet. If ITBs were so easy to make them work...then, please, show me a video of one working on a twin, driving on the street with no idle nor drivability problems. Heck, show me a video with one even working, even with idle/drivability problems. None??

The only cars with ITBs are super cars and real race cars that are highly developed and highly tuned.

I had a few friends running both indiv carbs and also the nicer ecu fuel controlled ITBs in the 90s on B series motors... better drivability?? hahaha...anything but! idle problems, start problems, street drivability problems, and the list goes on and on and on..

[michael336]

Originally Posted by fooddude

I get your point..but I find that very hard to believe. 1 TB will be much easier to make a car more drivable and have better drivability, from a single maf sensor standpoint. ITB's are very difficult to tune and make drivable - the exact reason 99% of manufactured cars have 1 TB and also the exact reason why you haven't seen a single video of ITB's working on a BRZ/FRS yet. If ITBs were so easy to make them work...then, please, show me a video of one working on a twin, driving on the street with no idle nor drivability problems. Heck, show me a video with one even working, even with idle/drivability problems. None??

The only cars with ITBs are super cars and real race cars that are highly developed and highly tuned.

I had a few friends running both indiv carbs and also the nicer ecu controlled ITBs in the 90s on B series motors... better drivability?? hahaha...anything but! idle problems, start problems, street drivability problems, and the list goes on and on and on..

Is itb means individual throttle bodies? I used have a Toyota Levin in 90's. It has 20v 4age engine, and uses that itb as orginal. The feeling was really different than other single th 4a engine.

[michael336]

Originally Posted by fooddude

I get your point..but I find that very hard to believe. 1 TB will be much easier to make a car more drivable and have better drivability, from a single maf sensor standpoint. ITB's are very difficult to tune and make drivable - the exact reason 99% of manufactured cars have 1 TB and also the exact reason why you haven't seen a single video of ITB's working on a BRZ/FRS yet. If ITBs were so easy to make them work...then, please, show me a video of one working on a twin, driving on the street with no idle nor drivability problems. Heck, show me a video with one even working, even with idle/drivability problems. None??

The only cars with ITBs are super cars and real race cars that are highly developed and highly tuned.

I had a few friends running both indiv carbs and also the nicer ecu fuel controlled ITBs in the 90s on B series motors... better drivability?? hahaha...anything but! idle problems, start problems, street drivability problems, and the list goes on and on and on..

My Levin had similar problem as you said when it was getting old, even it has not much mods.

[wu_dot_com]

Originally Posted by michael336

Is itb means individual throttle bodies? I used have a Toyota Levin in 90's. It has 20v 4age engine, and uses that itb as orginal. The feeling was really different than other single th 4a engine.

i think its a little different between the ITB (individual throttle bodies) of the past vs now.

the 20 v 4age ITB most likely are controlled by throttle cables. thus the PID lag with modern day drive by wire does not exist. i.e. timing, position of those throttle body are more consistent with the intended peddle position.

modern single TB like ours cars are electronic throttle body. thus at a minimum, one PID control is build into the ECU to obtain accurate reading/ command / position feedback.

with ITB, it goes a little beyond just simple plug and play. since instead of controlling one throttle, you need to have a PID control loop in each throttle body, and you need to integrate the 4 independent results into one single command that feeds into the main ECU PID.

unless each ITB feeds into a central harness that contains a chip for each PID and integrate the 4 PID into one single that feeds into the car ECU (which in stock form reads only 1 PID I/O), the feed back loop variation for ITB may be too great for the car ECU to compensate for.

[wu_dot_com]

Originally Posted by michael336

My Levin had similar problem as you said when it was getting old, even it has not much mods.

if you are having problem with the ITB on cable TB, then its either your cable tension is incorrect, or your position sensor (TPS) is warn/ bad.

im going to take a guess that the ITB used in that levin is a potentiometer. as with all potentiometer, they are cheap but can be prone to dirt and wear resulting in errors in its reading.

[michael336]

Originally Posted by wu_dot_com

if you are having problem with the ITB on cable TB, then its either your cable tension is incorrect, or your position sensor (TPS) is warn/ bad.

im going to take a guess that the ITB used in that levin is a potentiometer. as with all potentiometer, they are cheap but can be prone to dirt and wear resulting in errors in its reading.

The car had been sold like ten years ago. I don't know much about cars during that time. My dad brought it in 1991. I just got the driver license for one or two year. I would steal it and go out have fun. Haha.

[zooki]

I was thinking if you had ITB's you most likely would have an aftermarket ECU running speed density so you wouldn't need a MAF sensor. This is (roughly) comparable to the old dual plane versus single plane manifolds. A dual plane had better low end throttle response because the volume of air that had to be accelerated every time an intake valve opened was smaller than the larger single plane plenum. It's just a matter of airflow.

[Boxer486]

Originally Posted by fooddude

Very curious about this, if it's legit.

A humongo TB is probably the closet thing to an ITB setup for NA

What?

[Boxer486]

Originally Posted by michael336

I did rebuilt the engine with cylinder head ported and Hks higher compressor ratio head gasket, ported the intake manifold, ported catless exhaust header with straight cat back.

What was your CFM before and after porting? Got a graph or chart?

[Fear]

Originally Posted by wu_dot_com

i think its a little different between the ITB (individual throttle bodies) of the past vs now.

the 20 v 4age ITB most likely are controlled by throttle cables. thus the PID lag with modern day drive by wire does not exist. i.e. timing, position of those throttle body are more consistent with the intended peddle position.

modern single TB like ours cars are electronic throttle body. thus at a minimum, one PID control is build into the ECU to obtain accurate reading/ command / position feedback.

with ITB, it goes a little beyond just simple plug and play. since instead of controlling one throttle, you need to have a PID control loop in each throttle body, and you need to integrate the 4 independent results into one single command that feeds into the main ECU PID.

unless each ITB feeds into a central harness that contains a chip for each PID and integrate the 4 PID into one single that feeds into the car ECU (which in stock form reads only 1 PID I/O), the feed back loop variation for ITB may be too great for the car ECU to compensate for.

four throttle bodies operated by one "modual" and a cable to sync them ... doesn;t sound too complicated to me...

[wu_dot_com]

Originally Posted by Fear

four throttle bodies operated by one "modual" and a cable to sync them ... doesn;t sound too complicated to me...

the science behind it is nothing to sneeze at. the PID math behind the individual TB would be the same. the integration of the 4 throttle position into one single reading is a little tough since the control codes would need to adjust each TB independently to obtain a single readout. but eve still, an undergrad engineering SR that had a corse in control system could write that.

the challenge would be the power quality, radio frequency shelding (if needed), response time, both electrical and mechanical reliability, controllers longevity against environmental effects.

btw i don't know if this is what those race team is using for their ITB, this is just one way to do it, there are probably simpler and more effective ways to do it out there.

[s2d4]

Originally Posted by fooddude

Very curious about this, if it's legit.

A humongo TB is probably the closet thing to an ITB setup

WTF..

[fooddude]

Originally Posted by s2d4

WTF..

"OMG DUUUUDE, GNARLY BRO"



Anyways..

@wu_dot_com: But ya, I can understand the need of 4 separate PIDs into a single readout to even make it work ..but aren't, a lot of the "older" cable driven ITBs on inline 4's and even the modern electronic controlled ones too, just a single shared/the same long TB shaft, but with individual butterfly's connected to it and individual ports and used only 1 TPS sensor on one end of the 4 butterfly/port manifold/stack... (did that make sense?)...meaning, for modern electronic controlled TBs, wouldn't it still use a single PID?

Aren't ITB's NOT truly and totally individual? ...they just have individual butterfly's and ports/horns..but they share the same TB shaft, TPS and I guess the same electronic TB motor that operates the shaft. If our cars were inline 4, then wouldn't it really be just 1 PID still?

...I guess for these new boxer engines, I can see it would be just a tad diff; but still similar in concept - 2 butterfly's/ports (on each side of the boxer engine) sharing the same single shaft and sharing the same TPS and TB control motor...and hence..the same PIDs..?

[s2d4]

Originally Posted by fooddude

"OMG DUUUUDE, GNARLY BRO"

Ummm, ok since what you said totally made sense.