Hi all, i am just trying to understand if this is normal or wether there is an underlying issue.

My boost control setup is as follows

S300
Apexi boost solenoid (as came with an AVCR)
Supression diode installed (as per hondata instructions)

Wastegate pressure is 14psi no creep
@ 30% duty boost hits 2.1bar, @ 41/42% is hits 2.5bar
activation pressure is 1.56bar
solenoid frequency is 12hz
Single spring in each wastegate

As i understand from my tuner, we dont seem to have any control between the 14psi (just under 1 bar) and 1.7/8bar. This is obviously no good for BBG purposes.

Now i was expecting to have to run a much higher duty to see over 2 bar on my S372R, but it is what it is.

Would it be a case increasing the solenoid frequency to give me better resolution?

When i asked on the hondata forum, the advice was to remove the diode (something which they themselves advise to do) which didnt make much sense to me, but has anyone else found this improved things? I was not sure if the diode install was just for when using MAC solenoids or if it applied to all.

Would really be great to be able to sort this out soon so my drag times can come crashing down, the car at peaks power truly flies!! I just need to be able to sedate it in the lower gears!

 

Youre solenoid frequency is super low. AEm,hondata, (mac solenoids) Should be ran around 31/32Hz. And youre activation PSI should be around 3/4psi. Not sure why you have it activating So high?

Im not sure what the apexi Solenoid frequnecy should be ran at. I would get a AEM/Hondata solenoid and run it at 31hz. Change youre activation to 3-4psi and then re adjust duty cycle map

 

Try turning up the frequency. The higher it is the faster the solenoid responds. Which also means you get a tighter window for controlling it. example: add 1% duty cycle and get 1 psi of boost. The lower the frequency the slower it responds and you get a bigger window. example: add 5% duty cycle get 1 psi more boost.

 

Been thinking about this more and it could be due to the fact there is only a single spring in there, so the solenoid doesnt need to bleed off that much air to keep it closed. Maybe a tougher spring will help, however i do still want to limit power in the first 2 gears at least. So somehow i need to stiffen the spring but still make it open at 14psi!

I agree the activation pressure is way too high, but 3-4psi is way too low, you need to match that to just below the spring so that the turbo spools as quickly as possible, otherwise it will feel a bit lazy.

i have researched the solenoid frequency and it suggests running it at the same as the MAC one, so 31hz.

 

How do you have the ebc plumbed? That can affect the resolution and control.

 

Im comfortable that the solenoid is plumbed up correctly. Had enough issues with that in the past!

 

Yea i had issues with mine as well. Had to relocate the Pressure source and weld on a bung near my compressor output vs. Intake manifold.

Mine is set to 4psi and my spring is a 10psi. I dont notice it being lazy to spool at all.

Its more so it doesnt prematurly wear out youre solenoid. YOu could just set the boost to 30psi in the lower rpm(2-4000) range on the map. That will help fix the lag youre talking about. i usually set the lower boost values higher to compensate for that

 

depends on the size of the turbo though i guess!! mine hits full boost between 6500 and 7000rpm, so needs all the help it can get

 

Yea that makes sense....i realzie its a bigger turbo. To compensate for that you could put a higher target boost in lower rpms(where it would never hit that boost in that rpm) that should allow it too spool up as fast as possible.

 

isnt that what the activation pressure effectively does anyway though?

 

Im not 100% certain. But once it activates there should be a little delay before it takes effect i would imagine...I dont think it would be as accurate that way. When i had my boost by gear set-up this is what my tuner recomended me to do when i complained about the lag...He had stated you just dont want it at 1psi cause then the solenoid will be activating to often, causing premature wear. So when my target boost is 20psi i put like 25psi from 2-4k. Then at 4k its just getting to 20psi which is when i drop it to the targeted 20psi.


i can see youre logic though, that does make sense. thats just the way i have always done it. Try out different ways, i would def at least drop it lower then you have it now tho....and 31hz sounds good. The slower spool sometimes benefits me cause it creates a little less wheel spin by ramping the boost up slower.

 

Take a few datalogs and compare which is making it respond earlier, and/or more accuratlely

 

yeah i do that normally anyway, ill just have to wait a little while before i can get back to a quiet track to do all this sort of testing....

 

Good luck bro. Out of curiosity how much boost are you able to build off the line? You must be utilizing the anti-lag/launch control feature no?

 

on my old GT4094 i coudl build pretty much whatever i liked, which was an issue as i didnt have BBG then either!! so 2 bar off the line was um...interesting.

Im yet to try this setup, but if i could get something like 8psi i think that would be a good start.