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23 CTR, Boost Pressure limit causing throttle closure?
Posted: Tue Jun 03, 2025 12:36 pm
by NL_22
Model: 2023 Honda Civic Type R
Modification: RV6 exhaust, PRL intake, PRL intercooler, AWE exhaust,
DW 430lph low pressure fuel pump, XDI high pressure fuel pump,
XDI 2000cc injectors, RV6 660AS Turbo upgrade, Hondata Can-Flex kit.
Hondata Flashpro
I seem to be hitting some sort of limit on commanded boost pressure which in turn maybe is causing the ecu to close the throttle in order to keep BP in line with BP Commanded? From run to run, give or take...BP Command and BP would track closely till about 5500rpm, BP will wise to 27/28psi while BP Commanded is still targeting 25psi and then the throttle will start to close. It does it every time at 5500rpm and right as BP Commanded and BP start to differentiate more than 2psi. I've adjusted the AIRC table, raised the torque tables, raised the factory TC limit per mod option, adjusted the Turbo PA limit tables, raised the Turbine mass flow, wastegate flow table, and compressor efficiency table. No matter what changes I've made, BP Commanded seems to be limited at around 25psi and not tracking closely to actual BP. Below is the calibration and a couple logged runs. Any input will greatly be appreciated, Thanks.
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Tue Jun 03, 2025 1:01 pm
by jeffx
just a quick look at your logs it doesn't seem like your wastegate is opening nearly as much as the ECU thinks it is. You're exceeding commanded boost by a fair bit and it keeps opening the wastegate more and more but your boost is still holding at 27+psi with over 6mm of commanded wastegate opening at 5300rpms. By 7000 rpms it's commanding 7.2 which is pretty close to the max opening of 8.00 mm and your boost is still over 28psi. check the wastegate and the actuator.
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Tue Jun 03, 2025 3:06 pm
by NL_22
Thanks for the input, just saw that in the logs after you mentioned it. I'll do some digging but being that it's an electronic wastegate, there isn't much to adjust besides the calibration procedure.
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Tue Jun 03, 2025 3:52 pm
by jeffx
Correct. It could be a mechanical issue.
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Fri Jul 18, 2025 11:01 am
by NL_22
*Update* Took the down pipe off to look for any blockage or restriction at the wastegate flapper and there was nothing. Disconnected the electronic wastegate actuator from the arm, checked the flapper by hand it moved freely as it should. Reconnected the electronic wastegate actuator, used a scanner to perform an actuator test and was able to see it fully closed at 0mm of travel and open at 8mm with no issues. Just from dealing with other failed and or out of calibration actuators before, usually it'll set an error during this test but passed the with no problem. With that being said, the actuator is properly calibrated as well. Reinstall everything, perform another test run on the dyno and still the same result. Vehicle is targeting boost pressure at around 26psi but will over boost, throttle plate will start to close, and wastegate actuator is opening to almost the full travel of 8mm. I also have a 17 FK8 with a RV6 660AS and decided to do a comparison. Targeting around 26psi as well, boost pressure stayed steady, no throttle closure, and wastegate actuator was only opening to 4mm of travel at max. At this point, I am leaning towards that there is something mechanically wrong with the turbo not being able to bleed the pressure efficiently. Below is the FL5 calibration being used, 1 dyno log of the over boost, and 1 dyno log of the FK8 for comparison. Any more inputs will greatly be appreciated, thanks.
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Wed Jul 23, 2025 2:43 pm
by NL_22
Hondata? is the RV6 base map provided in the selection good enough to use as a starting point?
Re: 23 CTR, Boost Pressure limit causing throttle closure?
Posted: Thu Jul 24, 2025 7:45 am
by jeffx
NL_22 wrote: Fri Jul 18, 2025 11:01 am
*Update* Took the down pipe off to look for any blockage or restriction at the wastegate flapper and there was nothing. Disconnected the electronic wastegate actuator from the arm, checked the flapper by hand it moved freely as it should. Reconnected the electronic wastegate actuator, used a scanner to perform an actuator test and was able to see it fully closed at 0mm of travel and open at 8mm with no issues. Just from dealing with other failed and or out of calibration actuators before, usually it'll set an error during this test but passed the with no problem. With that being said, the actuator is properly calibrated as well. Reinstall everything, perform another test run on the dyno and still the same result. Vehicle is targeting boost pressure at around 26psi but will over boost, throttle plate will start to close, and wastegate actuator is opening to almost the full travel of 8mm. I also have a 17 FK8 with a RV6 660AS and decided to do a comparison. Targeting around 26psi as well, boost pressure stayed steady, no throttle closure, and wastegate actuator was only opening to 4mm of travel at max. At this point, I am leaning towards that there is something mechanically wrong with the turbo not being able to bleed the pressure efficiently. Below is the FL5 calibration being used, 1 dyno log of the over boost, and 1 dyno log of the FK8 for comparison. Any more inputs will greatly be appreciated, thanks.
did you try swapping the wastegate actuator with the one on the FK8? If it's not something with the actuator the only other thing I could think of would be if the wastegate port itself is somehow blocked but if you look inside the entrance to the turbine housing that seems extremely unlikely. It's a very simple flow path. If the wastegate port is truly opening 7mm at 6900 rpms, I just don't think it's physically possible for the turbo to still be pushing 28.2psi.