2024 MT MHD Stg 2+ Strange Intermittent Boost Issues. Limp Mode?

[ColonelAdama]

This is the opposite to my experience. MHD Stage 3 98RON OTS map, manual transmission has been smooth as warm butter. Are we sure this isn't bad fuel?

Yeah I have heard that the 93 map can be hit or miss depending on the fuel. Can't you log and check if there is knock/poor timing?

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[GQM]

This is the opposite to my experience. MHD Stage 3 98RON OTS map, manual transmission has been smooth as warm butter. Are we sure this isn't bad fuel?

Shell VP 93 couldn't resolve it permanently. The low boost mode would come and go even after several full tanks of only Shell VP 93 and that's about as good as it gets for 93 octane here in the states.

I'd also ask what your setup is as mods will play a role. If you read my background info from the first post, I have a bought from new brand new 24 Supra MT. Did a proper engine break-in the first 150 miles. Not beating the shit out of it and not milking it around for 1000k miles, but how you would break in a freshly built engine. Have catless 4.5" DP, full exhaust and eVenturi intake which actually makes more power over the stock air box.

Yeah I have heard that the 93 map can be hit or miss depending on the fuel. Can't you log and check if there is knock/poor timing?

Nothing in the logs for excessive timing pull or knock. All logs reviewed by CES, MHD and CD919. No one was able to identify a smoking gun. If it's not the tuning being adequate it's the boost spikes between shifts that was triggering it. Whatever CD919 did, made the shifts much smoother and normal. You felt the boost spikes if you didn't jump back on throttle 100% after the shift.

 

[ColonelAdama]

You felt the boost spikes if you didn't jump back on throttle 100% after the shift.

for what its worth, I experienced the same issue with JB4. The MT cars seem to close wastegate fully during the shift to reduce lag.

 

[BMWAF]

Shell VP 93 couldn't resolve it permanently. The low boost mode would come and go even after several full tanks of only Shell VP 93 and that's about as good as it gets for 93 octane here in the states.

Might be worth trying a different brand of petrol or at least try a different petrol station. I can't speak for the US but I know Shell V-Power (98RON) is dogshit here and I wouldn't use it to set a house on fire. Mind you, many people here in Australia suggest our petrol is worse than yours, but I'm not convinced.

I'd also ask what your setup is as mods will play a role. If you read my background info from the first post, I have a bought from new brand new 24 Supra MT. Did a proper engine break-in the first 150 miles. Not beating the shit out of it and not milking it around for 1000k miles, but how you would break in a freshly built engine. Have catless 4.5" DP, full exhaust and eVenturi intake which actually makes more power over the stock air box.

I have a MY23 MT which I also bought brand new. I broke the car in without much fuss for the first 2000km: While I didn't bang it off the limiter, I also didn't completely baby it as I believe in using the whole rev range during break in - not that I really believe in engine break in anyway, lol.

My mods are relatively light: I initially ran a JB+ for a good 12 months without any issues other than a pesky CEL when I replaced my downpipe. I'm Femto unlocked now with a 200 cel sportscat and AWE Touring exhaust. I also have a Turbo heat shield; aftermarket charge and intake pipes and a K&N filter in the stock aibox, but that's neither here nor there. I have also removed the CDV which is a waste of time. I drive (almost) exclusively in Sport mode on BP Ultimate (98RON) fuel using the MHD Stage 2 OTS (98RON) tune which as I suggested earlier, I simply cannot fault.

Hopefully someone with more knowledge can help because other than fuel, I honestly don't know what might be wrong but I'd be very surprised if it were the OTS map.

 

[Kobold]

I also have a Supra MT. I’m driving with a custom tune, because in Germany everything always has to be complicated if you want to stay legal. With the custom map I haven’t had the issues mentioned so far, but I’ve only been running it for about 3,000 km. I’ve never tested the MHD OTS Stage 2 map; I wanted to, though, because while the custom map is listed as 450 PS (≈443 HP) / 600 Nm (≈443 lb-ft) and is also registered in the paperwork, it actually makes 460 PS (≈454 HP) and 680 Nm (≈502 lb-ft) on the dynos. I feel that 680 Nm (≈502 lb-ft) is a bit too high for that power level, which is why I was considering switching to the OTS map.
Since the Femto unlock and loading the custom map I’ve only been running Aral 102 (RON), which is comparable to 95 octane in the US. I’ll keep a closer eye on it now to see if I notice any changes in boost. Never had limp mode so far.

 

[GQM]

Might be worth trying a different brand of petrol or at least try a different petrol station. I can't speak for the US but I know Shell V-Power (98RON) is dogshit here and I wouldn't use it to set a house on fire. Mind you, many people here in Australia suggest our petrol is worse than yours, but I'm not convinced.



I have a MY23 MT which I also bought brand new. I broke the car in without much fuss for the first 2000km: While I didn't bang it off the limiter, I also didn't completely baby it as I believe in using the whole rev range during break in - not that I really believe in engine break in anyway, lol.

My mods are relatively light: I initially ran a JB+ for a good 12 months without any issues other than a pesky CEL when I replaced my downpipe. I'm Femto unlocked now with a 200 cel sportscat and AWE Touring exhaust. I also have a Turbo heat shield; aftermarket charge and intake pipes and a K&N filter in the stock aibox, but that's neither here nor there. I have also removed the CDV which is a waste of time. I drive (almost) exclusively in Sport mode on BP Ultimate (98RON) fuel using the MHD Stage 2 OTS (98RON) tune which as I suggested earlier, I simply cannot fault.

Hopefully someone with more knowledge can help because other than fuel, I honestly don't know what might be wrong but I'd be very surprised if it were the OTS map.

Well I don't need to worry about the gas thing now that the issue is resolved for me with custom tuning. Having a cat vs no cat is a big difference on a turbo car, even if it's a "high flow unit". Being catless probably exacerbated the boost spikes. K&N filter in the stock airbox isn't going to change anything either. Most K&N style filters don't flow as well as a fresh paper unit. The eVenturi setup changes the turbo inlet to a larger diameter unit which I think is where the horsepower gain actually comes from. There's a video on YouTube showing a back to back dyno the same day where the eVenturi did 10 whp more than the stock air box.

 

[BMWAF]

K&N filter in the stock airbox isn't going to change anything either. Most K&N style filters don't flow as well as a fresh paper unit. The eVenturi setup changes the turbo inlet to a larger diameter unit which I think is where the horsepower gain actually comes from. There's a video on YouTube showing a back to back dyno the same day where the eVenturi did 10 whp more than the stock air box.

Pretty sure your intake, like CDV deletes and K&N filters, are all largely placebo, lol.

 

[Kobold]

Pretty sure your intake, like CDV deletes and K&N filters, are all largely placebo, lol.

I definitely noticed the CDV delete. Shifting from 1st to 2nd gear is noticeably better, but still not perfect. It does make a difference though.

 

[GQM]

Pretty sure your intake, like CDV deletes and K&N filters, are all largely placebo, lol.

Maybe

I definitely noticed the CDV delete. Shifting from 1st to 2nd gear is noticeably better, but still not perfect. It does make a difference though.

Deleted mine before I even drove the car. BMW ones always suck.

 

[BMWAF]

Maybe

Yeah.. I don't believe everything I see online anyway. Having said that, I'm pretty sure I saw a massive test of aftermarket intakes/filters and they all pretty much sucked, performance wise. I think that changing the intake on a modern car is more about aesthetics and cute noises than actual performance gains.

Deleted mine before I even drove the car. BMW ones always suck.

CDV delete did absolutely nothing for me. On my car, the biggest improvement to the 1-2 shift came from turning off the rev matching function. I seem to be pretty much alone in this but it is my experience none-the-less.

 

[maserati]

I have a 2025 6MT. CTS Catless downpipe, RK Titanium single exit exhaust, MST V2 Intake and Turbo Inlet, I also had issues with MHD Stage 2 93. I would sometimes go into limp mode after doing a pull. I switched to 91 and everything was running better. I always use Shell 93. Speaking of the CDV delete I did it and can say it was a massive difference. Especially 1st to 2nd. highly recommend it. Currently working on a custom tune with Mike Botti.

 

[ColonelAdama]

I just got 262144 limp mode today, wouldn't clear with the codes. Just drove for another 10 minutes and power came back. It is possible it was from "overboost" because I was banging off 1-2 shifts a few times before I lost power. I do see more corrections in the following logs compared to last time I went logging on this same tank of fuel.

Is that an indicator to replace plugs? Or does a tank of E40 really go bad within a month?

Edit: Few more logs and timing was fine.

 

[lucky phil]

I definitely noticed the CDV delete. Shifting from 1st to 2nd gear is noticeably better, but still not perfect. It does make a difference though.

This is the placebo affect "tell". Translation, It's a different "feel".
Phil

 

[tracer bullet]

This is the placebo affect "tell". Translation, It's a different "feel".
Phil

You quoted a post nearing 2 months old, so you could complain that someone liked the change in clutch feel after removing the restrictors in the CDV?

You've acknowledged that it can change how it feels, so why is it you can't ever turn down an opportunity to comment when someone notices or likes that change in feel? Why is this now the placebo effect (note the correct spelling) when you have very specifically stated that you believe it will change the feel?

These are rhetorical questions you don't need to answer. There's a lot of knowledge you have that's worth sharing, I've read some good things from you. But this subject you can't stop contradicting yourself on or being a pain in the ass about for no reason. It's kind of odd.

 

[razorlab]

You quoted a post nearing 2 months old, so you could complain that someone liked the change in clutch feel after removing the restrictors in the CDV?

You've acknowledged that it can change how it feels, so why is it you can't ever turn down an opportunity to comment when someone notices or likes that change in feel? Why is this now the placebo effect (note the correct spelling) when you have very specifically stated that you believe it will change the feel?

These are rhetorical questions you don't need to answer. There's a lot of knowledge you have that's worth sharing, I've read some good things from you. But this subject you can't stop contradicting yourself on or being a pain in the ass about for no reason. It's kind of odd.

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