Low boost?

[mbrishke]

Just bought a 2019 CTR with 16k miles. it was well maintained, completely stock, and as far as i can tell, hasnt been "returned to stock" every nut and bolt was in place, with none showing wear from being previously removed etc.

However, the boost seems a bit more laggy than it should for a turbo this size(I've owned and built 2 turbo RSX's).
it seems ever so slightly hesitant to build boost, starts building around 3k, by 4-4500 it tops out at 15PSI and starts dropping until about 9 at redline. I actually took it to honda, explained the problem, and they replaced the fuel pump recall, and told me the boost was fine, I argued with them for about 30 minutes, knowing the car should be making more boost than that, then the "master tech" told me it's because of elevation(colorado springs, 6,500ft) im like no way man, it would be waining down to only 9lbs from the factory rated 23. It doesnt feel terribly slow, so I'm wondering if maybe the gauge is just off somehow? But that seems unlikely.

Anyway, they said they have another guy who is good with the type R's that will be in tomorrow, but as much as I didn't want to do this myself, I'm going to go leak hunting tonight because I don't have much hope for them.

In the meantime, I was hoping someone on this forum might have some insight. Is there a most common area for the leak to occur? I checked the charge piping that you can get to without removing the bumper already(from intercooler exit to TB). And everything seemed fine. Thanks in advance for any response.

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[kefi]

15psi sounds about right for such high elevation. Even my tuning customers with a custom tune see 18-22 at best at 4500 and such a high elevation, compared to the 27-29psi and 22psi by redline at sea level. The ECU has an extremely conservative turbo compression ratio limit that is affected by elevation and intake temps.

There is no set PSI that these cars target, it’s entirely based on maximum compression ratios and a dynamically targeted boost level. It’s a torque management based ECU. PSI also isn’t the end all be all measurement for how much boost you’re actually making. I wrote a blog post about it here: https://fk8.clinic/blogs/type-r-tech/boost-pressure-can-be-deceiving

That being said, the most common leak spots are the throttle body coupler (especially this), the pipe coming off the turbo, and the intercooler O-rings.

 

[mbrishke]

15psi sounds about right for such high elevation. Even my tuning customers with a custom tune see 18-22 at best at 4500 and such a high elevation, compared to the 27-29psi and 22psi by redline at sea level. The ECU has an extremely conservative turbo compression ratio limit that is affected by elevation and intake temps.

There is no set PSI that these cars target, it’s entirely based on maximum compression ratios and a dynamically targeted boost level. It’s a torque management based ECU. PSI also isn’t the end all be all measurement for how much boost you’re actually making. I wrote a blog post about it here: https://fk8.clinic/blogs/type-r-tech/boost-pressure-can-be-deceiving

Do you think the boost pressure dropping to about 9-10 at redline sounds right?

 

[kefi]

Do you think the boost pressure dropping to about 9-10 at redline sounds right?

On the stock calibration, yeah. The top end is pretty heavily neutered. How hot was it? Temps play a huge role in this too.

If you have a scanner you can try reading the fuel trims to see if it’s heavily negative at WOT. That would indicate a boost leak.

 

[mbrishke]

On the stock calibration, yeah. The top end is pretty heavily neutered. How hot was it? Temps play a huge role in this too.

If you have a scanner you can try reading the fuel trims to see if it’s heavily negative at WOT. That would indicate a boost leak.

Nah, no scanner. I was planning on getting hondata but wanted to get this sorted out first. Maybe I'll just take a 4-5 hour road trip to get closer to sea level and see what happens. Or I'll try to flag down and ctr in the area, I've seen two or 3 ?‍

 

[mbrishke]

On the stock calibration, yeah. The top end is pretty heavily neutered. How hot was it? Temps play a huge role in this too.

If you have a scanner you can try reading the fuel trims to see if it’s heavily negative at WOT. That would indicate a boost leak.

Thanks again for your input Kefi.
Figured I would add some closure to this in case anyone else runs into the same scenario. I'm comfortable saying those are normal boost pressures for this car at 6,000+ ft of elevation.

I made an hour and a half drive down to an area at about 4500 feet of elevation, and the boost levels went up to around 19 max with 14 at redline.

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