Page 1 of 1

boost control issue?

Posted: March 6th, 2026, 10:30 pm
by Tomtek223
Hey guys, im having trouble getting the car to run outside of gate pressure, It has a kinugawa ko4 supercore, billet wheel. Corksport hpfp, xforce 3 inch catback, k&N panel filter. Im running the 98 eu High load base on VT lite.

no matter what tune I flash, I cannot seem to escape gate pressure with 1 bar spring. wgdc is capped at 100% on pulls and absolute load gets to 1.6/1.7 max at 15.5psi.

everything is confirmed plumbed up as per oem turbo was. I have checked 100 times for boost leaks with soap, smoke ect, nada.
VersaTuner Logs.zip
(10.11 KiB) Downloaded 19 times
attached, third gear pull with shift at end. please help :banghead

Re: boost control issue?

Posted: March 8th, 2026, 3:15 am
by mituc
For the next logs please load this dashboard preset on to your versatuner (Dashboard -> presets -> import and then load):
https://www.dropbox.com/scl/fi/s7e5zpu3 ... mrf04&dl=0

If you are still on the factory boost control setup, it looks to me like the pressure coming from the turbo compressor is not escaping the wastegate actuator. This means that either the lines going to the EBCS are connected backwards or the EBCS is stuck closed (assuming that the adjustable wastegate arm is not set at full length, I've seen that before as well).

Maybe it's time to switch to a 3-port/interrupt setup and get a proper tune, the OTS will not make justice to that turbo nor to your setup.
Let me know if you need any guidance.

Re: boost control issue?

Posted: March 8th, 2026, 4:17 pm
by Tomtek223
Thats sorta confirms my suspicions, im not looking for crazy power ect as its a high km daily. for a more budget friendly alternative, the turbo housing barb is already restricted. Could putting a futher restrictor to reduce flow to the gate potentially? Or if I got the corksport 3 port solenoid is there a rough value I could alter to achieve running the OTS tune?

Alternatively I also have a 3 port mac from an evo I had lying around. Is there an OTS running a similar setup?

Re: boost control issue?

Posted: March 9th, 2026, 9:31 am
by mituc
The MAC valve based EBCSs (all aftermarket except CS) and the Corksport one all use similar parameters. However, although there are some maps for a grimspeed EBCS, the calibration values are not ideal. But in your case this is not the problem... if anything you should feel the car being too twitchy and over reacting because building boost too fast/soon, while you either have a wastegate actuator setting issue or a EBCS/lines issue which is basically on the opposite side of this.