RomRaider

I would like to better understand the role that Tumble Generator Valves (TGVs) play in our engines.

Lots of people are quick to remove TGVs because they are a flow restriction at high intake flow rates. You can make more peak power without them. But I would like to know if TGVs could be used to increase volumetric efficiency (VE) at low intake flow rates. I believe closing or partially closing the TGVs could increase torque at low RPM and part throttle conditions, and could deliver faster throttle response on corner exit.

Does anybody know if control of the TGVs is possible? Is there a programmable map for TGV position? The best info I have been able to find has been in this thread:
http://www.romraider.com/forum/topic3386.html

I would be interested if anybody has TGV datalogs of 2007+ vehicles.

Suzuki uses secondary throttle valves in some of their motorcycles for this exact purpose, as well as aiding in emissions and smoothing out the rider's throttle inputs.

Here's a video explaining Suzuki's system:
https://www.youtube.com/watch?v=hdj1QMSl3OI

Thank you

what your describing is basically how most of the 08+ canbus cars operate, it was kind of implemented on the 07 USDM cars but the global market got the same features and more in the 08+ model year.

The idea is at certain load/rpm thresholds the TGVs will close, once you cross the threshold the TGV will open. There's a separate set of tables for TGV closed ignition and AVCS to try and optimise the reduced flow and there are some gains to be had on fuel economy - if you can keep the throttle/rpm/load within the TGV closed thresholds.

Thank you for your reply bludgod!



I have a 2005 STI with single AVCS EJ257. Would it be possible for me to use a 2007 ECU on my engine to gain TGV control, and disable exhaust AVCS control? Or would that be a massive can of worms?



I've also been trying to find out if TGVs are binary. Are they open/close only? Or can they be held at any position?

05 to 07 you would have to study the wiring diagrams for your market, with an EDM car it wouldn't work (EDM 2005 is still 2.0 and cable throttle). So long as your pinouts match up and you can sort out any immobiliser bits then in theory yes you could do that. No need to disable the exhaust AVCS as the 07 didn't have it. Fitting an 08+ ecu to your 07 or older car isn't gonna be a runner due to the canbus stuff your car won't have.


as far as I understand the ECU just has open or closed positions for control, but with an aftermarket controller you could probably make them do something weird. Problem you'll have is keeping left and right in sync and exactly the same amount of % open so just open or not open is likely the easier route to go down.

I should have specified this is all USDM. Glad to hear I was mistaken about 2007 and dual AVCS. That makes this more possible for me.



That is a really good point that I hadn't thought of.. each TGV has position sensors in addition to the motors, so it's possible in theory. But this idea keeps getting more complicated the more I consider the complications. I think for now I will leave the TGVs in the car and let the ECU control it normally. Maybe I can tackle this someday in the future. Thank you for your input!

yeah - i would guess that's why the 08+ cars have a different setup for TGV operation with the motor/sensor in a combined fancier looking unit (perhaps constantly open/closing during driving in the 07 ones caused them to wear out quickly?)