So decided to take the car out for a beautiful Wednesday drive, and decided to do some WOT pull in 3rd starting at about 3800rpms in my car. Noticed something I haven't noticed before. The car seems to temporarily over boost (Defi Racer gauge) to about 28-29psi. I decided to watch my AFR's on the next pull, with the same conditions (@ 3800rpms) and noticed I'm running what I would consider to be rich. My AFR's go from 11.2 to 10.6 and settle @ roughly 10.9 up to 6000rpms. All this in 3rd @ 3800rpms then going instantly into WOT. I know that im tuned for 25psi, and understand you might overboost just slightly, but it should taper quickly back to what you are tuned for. I was also under the impression that the X's preferred AFR's a bit leaner like 11.2-11.3. Should I be concerned?

Any insight to why this overboost and what seems to be richer then necessary condition may be happening would be greatly appreciated. I checked IC Pipes to make sure I didn't have a boost leak. Everything is solid tight.

 

check your fuel trims. If they are adding fuel then they'll add fuel at WOT as well.

 

Fuel maps are usually tapered upwards so it becomes richer when your load increases. So higher the boost usually means richer AFR.

Are you running the stock boost control solenoid? Are you going over your target load? Is WGDC correction kicking in?

 

Seems like WGDC correction is kicking in because boost does taper back to about 26psi (though im tuned for 25psi). In terms of being able to log my TRIMS, I dont have a tactrix cable and EVOscan so I cant view this. I don't get an SES when I over boost. Might have to talk to Bryan@GST (he tuned my car) about this. I'm going to take her back out later this evening and see if I can replicate what I did in 3rd again as well as watch 4th from the same conditions. Looks like its time to find a cheap laptop and Tactrix Cable so I can log.

 

If you're tuned by Bryan, I'm sure he'll take of the problem if there is any.

But yeah, it might be a good idea to purchase some sort of logger.

 

Agreed. Bryan has been uber good to me and my car. I completely agree with it being time to get a logger of sort. Might just do the EVOscan Standalone setup. Looks to be exactly what I need to log and monitor multi aspects that I should be keeping an eye on (considering my car is now far from stock).

 

Heres something I didn't think about. When I was tuned with bryan I was running the Green Fuel Pump relay, but then about a month later Mitsu released the Blue relay so I decided to swap the relays for safety (really don't want to grenade my motor over a $20 relay) reasons, and this has been the first time in a bit that I've been able to go WOT as the weather around my area has cleaned up and roads are dry.

What do you guys think? You think it could be the new relay causing the rich like conditions? Still doesn't explain why the car hits such high boost like 28-29psi and tapers to 26ish psi when I'm tuned for 25psi???

 

I had a Defi racer gauge, and it read way high in my VIII.
I have total faith in Bryan's abilities, I am sure the car is fine.

 

I was thinking the same thing. Maybe the gauge itself is funked and doesn't read (or has trouble quickly adjusting to on coming boost)...As for Bryan I too have 100% faith in his abilities, and I'm sure he will read this, and contact me to have a look at it. He really is great, and super supportive to us EVO guys out here in Nor-Cal, as well as to everyone here @ evom.net. I sometimes think how lucky I am to be as close as I am to GST Motorsports, and Speed Element two of the best shops in the business.

 

Hey Stephen,

One thing to note is that the Defi's all read high. Usually about 1-2 psi high. So if you are seeing a peak of 28-29 psi then its about 26.X-27.x psi and if it settles to 26 psi its probably around 24.X psi.

It's normal for my tunes to dip a little rich on overshoots from target. This is how I set up the fuel mapping, just for this reason. It also will run less timing. It is also normal for slight boost target overshoots, the system will correct it by design and tuning. Boost will always fluctuate depending on weather conditions. This is what the error correction system is designed for. To accommodate and correct accordingly.

I disable fuel trims affecting WOT fueling.

- Bryan

 

Thanks for chiming in Bryan! Makes far more sense now, and had a feeling that the gauge was a bit off.

Hey you ready for cams? Really hoping to hit that 400whp mark (if the tranny/tcu will allow)!