adjustable T-VIS

Toxygene

Active member
Would it be possible to pull the Temperature sensor out of the AFM and or use some other kind of temperature sensor to let the ECU know what's going on for those cold day instances?
 

darryl_p

New member
the controller also needs to be able to stop ECU switching the TVIS.
the later 3S-GTE ecu's switch the tvis to ground, thus openning the flaps in the runner way too early. i mean i know i produce more power at low revs when the TVIS is shut, hence improving low end VE. nad i want to be able to get them closed until higher throttle opennings... ie from my post before, mine is always open once past 18% on my throttle logging. thats actually a really small amount to push on my pedal... i'd like the limit to be able to be raised to maybe 35% ? thus keeping me in closed loop operation longer.

is this still possible with your hardware ?
 

BriinumsBo

New member
darryl_p":vzcv9ede said:
the controller also needs to be able to stop ECU switching the TVIS.
the later 3S-GTE ecu's switch the tvis to ground, thus openning the flaps in the runner way too early. i mean i know i produce more power at low revs when the TVIS is shut, hence improving low end VE. nad i want to be able to get them closed until higher throttle opennings... ie from my post before, mine is always open once past 18% on my throttle logging. thats actually a really small amount to push on my pedal... i'd like the limit to be able to be raised to maybe 35% ? thus keeping me in closed loop operation longer.

is this still possible with your hardware ?

im currently reading too much info on this, im interested in a project in my mind and dont know where it`s heading. Nokia N810 internet tablet + Arduino control board. the arduino board ahs voltage inputs and outputs and can talk to PC over USB. id really like it to talk to nokia internet tablet! im still waiting for the board. in theory, there is no need for the nokia to control the tvis. the arduino board is programmable, just set "if rpm(V) > xx or TPS(v) > xx { [open TVIS] }"

i just dont understand the logic of TVIS, why its supplied ground when closed and nothing when open? so with engine shut they`re open?
 

apampe

New member
I've made a lot of progress on this project since this thread was going. It does not take into account engine temp, as that was not found to be of any benefit. It's pretty basic logic activating T-VIS if the pre-set RPM and Throttle are there. Anyways, just wanted to post an update, and say it's working great. I can't advertise on the forums so I suppose you should PM me if you have any further questions for me.

Thanks for your input!
 

apampe

New member
I've taken a video of the T-VIS controller and it's on YouTube now

http://www.youtube.com/watch?v=D4-7dCixXe4

Also, I'm testing out one which also uses the MAP sensor, so the logic on my test vestion is: if ( (RPM is above setting) AND (Throttle is above setting) ) OR (MAP pressure is above setting, aka boosting)

This would open the T-VIS when the turbo is spun up at lower RPM's. This is generally not ideal driving, but if you go get it bogged down with the turbo boosting, the T-VIS should probably be open. I'm both researching and testing this. Does anybody have any comments on including the MAP sensor?
 

apampe

New member
Well, the alltrac uses the Airflow Meter instead of a Manifold Air Pressure sensor to determine fuel output, but the Turbo pressure sensor is on the manifold, so I'm playing around with using it or an after market pressure sensor I have that costs $15. So far my after market sensor is more accutare but I think the Turbo Pressure Sensor (really a ManifoldAirPressure sensor too) should be plenty accurate enough.
 

Shaggz00

Active member
Awesome progress! I'd love to get my hands on one.

I think that if I were setting it up for my car, I would primarily use the RPM to set up the operation point. I still don't understand how operation based on boost is beneficial though. Could you explain it a little moreand how you plan on setting it up? An example scenario or something.
 

Rpz123isme

New member
I bought one of thoses controllers off of ebay a few weeks ago. Funny thing is the guy left me good feed back but he refuses to return my email's about the tracking number. I will keep you guy's updated on his business moral and let you know if I ever get this thing!
 

apampe

New member
I'm really sorry about that shipping mistake. I got a eBay message from you which I apologize for not being on top of for 1 week but not any e-mails which are checked daily!

Also it was suppose to be shipped last Monday the 28th, and has been in UPS hands since then (unpaid shipping but in their hands, which was the mistake). That's one week + one day late. I'm really sorry for that but please don't elaborate and say it was 3 weeks!

It should be on it's way now. Check your PM.
 

apampe

New member
I agree the controller is primarily for RPM adjustment, which was my motivation for making them, since I needed to adjust the RPM myself.

Now, the driver really never should have signifigant boost at lower RPM's, basically because it's bad on the engine to bog it down, and it's tuned for horsepower with boost at high rpm's so theres no reason to. The driver should downshift at that point. BUT, when the driver does bog the engine down (low rpm, high boost), the T-VIS is closed (both stock and with the controller). The more I study intake rails I believe that the T-VIS should be open under that unfortunate condition when the driver bogs down the engine with boost.
 

Rpz123isme

New member
Thank you for the reply. And I am sorry for being impatient I just got upset after 8 days went by with no reply. 8)
 

darryl_p

New member
from my own testing of a variable openning point.... it seems the later toyota ECU seem to be half way correct in picking the right openning point for the tvis.

it should not be rpm alone based. you can do a dyno run with it closed and open, and at wide open throttle you have the best change point. but under less throttle and less boost its at much higher rpm points.

so basically its airflow that dictates the best point to open. at higher boost, you flow more air, and its lower. i guess the next best thing to try will be the AFM signal.
its clearly half the runners in the inlet plenum closed, will always increase air speed , and thus give better power, until at a certain airflow, you have enough volume of air that it becomes too high, and then all runners open, give enough air speed and the advantage of more easy to flow path thus making more power.
 

apampe

New member
True, it's really a flowrate issue. I've been playing around with the using the following to get flowrate, then open at a flowrate threshold. I'm not showing values or units here but let me know if you want more detail:

flowrate = RPM X MAP
(i need to research a more specific equation; I don't believe this is linear)

or

flowrate = AFM reading

So I'm tapping the turbo pressure sensor for a MAP, but it'd be nice to have the full negative range (not essential here though), so I'm also testing with an aftermarket pressure sensor. The AFM is yet to be tapped but it's high on the to-do list.


all in all, the RPM adjustment has been working really well for me.
 

Toxygene

Active member
Awesome progress!

I wonder if the guy who is hacking the ECU could give you any other details on the way Toyota controls the TVIS.

Not to mention... I wonder what the progress on the programmable OEM ECU has been also?
 
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