KR and Throttle Position

Tuning discussion for all second generation Mazda 2.3 MZR DISI Turbo powered vehicles
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BS199
Posts: 3
Joined: November 26th, 2022, 5:27 am

KR and Throttle Position

Post by BS199 »

Hi just did my first WOT log in my gen 2 mps on the high load map and as you can see i have had knock from 3300rpm to about 5800 rpm it only reaches around 2.35 degrees at the start of the pull then tapers down slowly all the way to 5800rpm.... also in the log my throttle pedal position is 66 percent and my actual throttle only reaches 77 percent should this not be at 100?
Attachments
MANS FIRST LOG YEAHHH.csv
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mituc
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Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: KR and Throttle Position

Post by mituc »

What tune was on your car when you took this log and what mods do you have?
The KR registered in the logs may have different causes, as far as I can tell this was a 3rd gear log so one of the reasons may have been the fact that traction was not excellent.

Also the fuel rail pressure is way too high, the relief valve would work continuously when the fuel rail pressure is ho high and you will damage it in no time. What tune is that?

On gen2 the acceleration pedal position goes only up to 66%.
The throttle position will only go up to 77-78% and that is the maximum opening. Past that, if it went more, the butterfly in the throttle body would start closing the opening.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
BS199
Posts: 3
Joined: November 26th, 2022, 5:27 am

Re: KR and Throttle Position

Post by BS199 »

High load base and 2.67 inch Corksport SRI, Ebay TIP, Autotech HPFP, GFB BOV. It was a 3rd gear pull and there was no traction loss... and yeah i thought the PRV was supposed to release at 1850 psi but in other peoples wot logs i have seen peaks of around 2000 so is this not normal?
mituc
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Posts: 1324
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: KR and Throttle Position

Post by mituc »

BS199 wrote: December 1st, 2022, 1:33 pmIt was a 3rd gear pull and there was no traction loss...
Sometimes you can't really feel it in the car, but the stability control module will react to it and will send signals to the ECU.
BS199 wrote: December 1st, 2022, 1:33 pmand yeah i thought the PRV was supposed to release at 1850 psi but in other peoples wot logs i have seen peaks of around 2000 so is this not normal?
Fuel rail pressure peaking so high is not really a good thing. If it peaks/spikes to like 1900 - ok, but staying consistently that high or spiking to 2000 (the fuel rail pressure sensor will read up to like 2055 or so, meaning 2000 is very very close to its limit) is certainly not a good thing.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
BS199
Posts: 3
Joined: November 26th, 2022, 5:27 am

Re: KR and Throttle Position

Post by BS199 »

I have since changed the base tune to the SRI/CAI base tune and do you think the FRP is better in these logs.... i think they seem to bounce more around the 1800s now maybe its because the AFR,s are a little leaner in this map?
Attachments
2ND LOG SRI MAP.csv
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1ST LOG SRI MAP.csv
(15.68 KiB) Downloaded 53 times
mituc
VersaTuner guru
Posts: 1324
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: KR and Throttle Position

Post by mituc »

The fuel pressure is built using mechanical work from the intake camshaft, and it's regulated via the spill valve solenoid in the top of HPFP. Therefore the AFRs have nothing to do with the fuel rail pressure. However if the fuel pump is at its limit then richer AFRs will cause lower FRPs, not the vice-versa. But with upgraded fuel pump internals and an OTS tune nothing will be close to any limit.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
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