I have a JDM IX, just fitted a 3" TBE and under acceleration the car is hitting boost cut, it builds then cuts out for a second, which causes a jolt, then re spools, then cuts again.

I presume this is down to the boost spiking due to a decrease in exhaust back pressure. Now i have been tickering with ECUflash, but since i just got my exhuast i haven't made any changes other than the RS VVT map and i haven't got a wideband yet so wouldn't fncy having a play until that is purchased and fitted.

I will be fitting my HKS EVC VI in a few weeks, but what safe ammendments can i make to the ECU parameters in order to eliminate the boost cut?

Much appreciated

 

Boost Limit table!

do a 2byte load log of your car to see what loads you are hitting then adjust the table accordingly.

if you have a map sensor do a log of that as well to see how much boost your hitting

 

Thanks tephra i'll try and have a look this evening,

Boost limit is already set at 260 accross the rev range, with regard to that value how wrong am i in assuming that it's meassured in bar so does that mean when it spike to 1.6bar it's cutting? I dont want to remove the protection as i assume again that is in place to protect the car from running lean so what sort of parameter can i set it at that will enable me to still have a safety margin in place?

 

nah it doesn't really correlate to psi/bar, do the 2byte load log to be sure before you up it.

 

or simply bump it up 5 at a time until the problem goes away but monitor knock to make sure it's safe where you're allowing it to go.

 

As a guide ralliart ecu's set the boost cut to 319% on e7 roms

So I'd guess if you upped it to around 300% it should stop you hitting the boost cut for now

 

This basically disables the boost cut all together. This isn't really safe since if anything ever goes wrong you've just lost another safeguard.

 

agreed, best thing to do is tune and log your boost+associated 2byte load then add 20 and put that into the table.

 

If he is already at 260 and is hitting the cut, then it would need to be around 280 anyway, so by setting it to 300 thats adding the 20 that you suggested ???

 

well if he is hitting 280 then he should probably check his boost, hitting loads that high and not knowing it is dangerous..

 

OPs car is a JDM Ix so he can log boost easily. 260 is way low for that type of car, 1.8 Bar will see you around the 280 mark so a boost cut of 300 is pretty sensible.

MB

 

WOOA BABY!

you need some 30mm head studs to hold that sucker down

 

He he, i've edited in the point now!

MB

 

319kpa doesn't disable boost cut, it's still a 319kpa...I found out with the HTA 35R @ 30psi on pump gas

you have to bump up the delay timer too to truly disable boost cut.

 

Thanks MB, I didn't think I was going too over the top, when I said 300, however I didn't have any sleep last night, so I could have got it wrong