How much of an effect can gain have?

[After-Glanza]

Just wondering here how much the gain settings on a boost controller can have an effect on a car. I have a basic understanding of it and that increasing it can increase the rate at which your turbo builds boost, but that it can cause overboost or spiking if too high a setting is used.

I'm running a forged td04 externally gated setup and using a blitz dual sbc. The gain on it is currently set to zero. I'm getting a final map on the car when chris gets the chance to do it for me and I'm just wondering if fiddling about with these settings when he is doing the map could help with the cars response?

Also in a previous thread someone mentioned playing about with my gain settings could help compensate for a bit of boost drop I was having in high revs, could the very low gain setting be contributing to boost drop a wee bit?

Cheers in advance to anyone who has some useful input.

 

[Texx]

Might be of some interest to you:

http://www.toyotagtturbo.com/forums/showthread.php?t=66394&highlight=gain+duty

 

[After-Glanza]

Cheers for that pal, rep added. Hard to know whats right though as i think theres a 1bar spring in my external gate and spuddy was saying in the thread you posted that his gain setting was 40. Surely if mines at zero there should be a good chance that increasing it a bit could help with response.....

I'm gonna play about tomorrow with the duty set to zero on a different setting to my usual so im running wastegate pressure (1bar) and fiddle about with the gain on that and see if it makes any noticable difference.

Wouldn't try it at the 1.3 bar setting as it might start spiking and causing det or something. I'll leave that to chris if he thinks its a good idea.

 

[Texx]

Basically the duty setting is the amount of adjustment the controller will make (or the percentage of time it will bleed air away from the wastegate or actuator to produce the desired boost pressure) and the gain setting is how often it will make the adjustment.

Assuming the duty is set correctly, increasing the gain setting can allow the wastegate to stay closed nearer to it's opening threshold point and in doing so help the turbo to produce the desired boost pressure more quickly, but if the gain is set too high the wastegate may not open soon enough and boost pressure will likely spike above the desired level.

 

[After-Glanza]

Had a wee play about tonight with the settings.

With the gain set to 20 instead of zero and using the same duty cycle setting my boost changed from around 1.3bar to 1.2bar and it was holding quite nicely. I found it strange that the boost decreased when i did that but after trying out the old settings, it was deffo the increase in gain that dropped the boost. You would just up the duty in order to compensate for this.

Even with the lower boost level the car felt just as quick as before and seemed to have more of a low down punch rather than the gradual power delivery it had before. This could maybe be due to the boost coming in a bit harder or something.

So i've basically learned that there should be a considerable advantage in using this when i come to get my car mapped soon. I can deffo see it aiding in the response of the car and help give more of a low down kick.

Just gonna wait now and fiddle about to find the perfect setting when im getting it mapped. Such a simple thing but will hopefully make a difference on the road....

 

[gorganl2000]

well....with the gain function its kind of trial and error...as every set up is different in its own way

set your desired boost level....then try to slowly go up with your gain UNTIL you spike over the desired boost level...then lower the gain function slightly...and that should give you a pretty reasonable base

the gain function really helps in getting back some response/spool earlier

knowing that some of you guys have different weather conditions, you may need to tweek it from hot to cold conditions

 

[After-Glanza]

Is it safe to play about with the gain? My cars mapped at 1.3 bar and I just wanna know if I can play about with the gain and duty to get it boosting 1.3bar again but with a higher gain value to aid response.

Don't wanna blow anything up lol

 

[gorganl2000]

i would advice you get the car tuned again...just to make sure...all these things are tuned as a "package"

see...u are trying to bring on boost earlier....so you could potentially throw your maps off..........depending

a check would be advisable to make sure a/f and ignition are in order ....last thing u want is to blow your engine



see what some of the tuners say

 

[After-Glanza]

Yea that's what I thought. Cheers for confirming that though. I was only playing about with it at a lower boost setting and was a buy cautious of trying it at the same boost. Rep added.