Sponsored

Catless dp on MT

MacronT

New Member
First Name
Macron
Joined
Dec 28, 2025
Threads
0
Messages
2
Reaction score
1
Location
Seattle, WA
Car(s)
Supra 2.0, A90
I’ve seen plenty of people run catless downpipes on manuals without issue. As long as the tune is dialed in and you’re aware of emissions implications, it’s not inherently “bad” for a manual. Curious what reasoning they gave?
Sponsored

 

PowerGetter

Well-Known Member
First Name
Randall
Joined
Feb 26, 2024
Threads
14
Messages
275
Reaction score
566
Location
Long Beach, California
Car(s)
24' Supra 3.0 MT... the Orange one
I’ve seen plenty of people run catless downpipes on manuals without issue. As long as the tune is dialed in and you’re aware of emissions implications, it’s not inherently “bad” for a manual. Curious what reasoning they gave?
it's the overboost from the reduced backpressure, because there's no longer a cat present. People saying they're not having issues is because they're not actually looking at data and just talking out of their ass because their car hasn't blown up.
 

BMWAF

Well-Known Member
Joined
Jul 1, 2022
Threads
70
Messages
3,077
Reaction score
4,440
Location
In orbit
Car(s)
A90 Supra; FN2 CTR
it's the overboost from the reduced backpressure, because there's no longer a cat present. People saying they're not having issues is because they're not actually looking at data and just talking out of their ass because their car hasn't blown up.
That seems a little extreme. 200 cell sportscat on an MT here and haven't felt anything untoward. Admittedly I haven't had the chance to take any logs yet, though.
 

PowerGetter

Well-Known Member
First Name
Randall
Joined
Feb 26, 2024
Threads
14
Messages
275
Reaction score
566
Location
Long Beach, California
Car(s)
24' Supra 3.0 MT... the Orange one
That seems a little extreme. 200 cell sportscat on an MT here and haven't felt anything untoward. Admittedly I haven't had the chance to take any logs yet, though.
a 200 cell has significantly less backpressure, but still more than a catless. Not insinuating that peoples car will blow up, just making a point that many people say things without having data. Yes, you can run catless without a tune, but doesn't mean there's no underlying issues. It's not catastrophic and it's not really noticeable, but it's there.
 

BMWAF

Well-Known Member
Joined
Jul 1, 2022
Threads
70
Messages
3,077
Reaction score
4,440
Location
In orbit
Car(s)
A90 Supra; FN2 CTR
a 200 cell has significantly less backpressure, but still more than a catless. Not insinuating that peoples car will blow up, just making a point that many people say things without having data. Yes, you can run catless without a tune, but doesn't mean there's no underlying issues. It's not catastrophic and it's not really noticeable, but it's there.
Yeah, true. But as imperfect as they are, OTS tunes.. are still tunes.
 

QTR FMS

Well-Known Member
First Name
Fahad
Joined
Nov 4, 2025
Threads
4
Messages
52
Reaction score
24
Location
Qatar
Car(s)
2024 6MT
FYI,

there is nothing wrong with running catless dp over catted.

you wont blow up the engine with stock or ots tune. You might if you have lots of knock which is irrelevant.

you can overboost as much as you want nothing will happen to the engine, the dme logic is really advanced and can protect the engine for probably anything.

the only issue you might have with oveerboosting is when the throttle is closed and the boost pre throttle is high, then you might cause surging and damage the thrust bearing and cause the seal to fail and leak oil. But what are the odds

6MT is underrated but its mostly because ots are not perfected yet, if mhd can work with its customers we would get much further with the platform.

im waiting for standalone ecus to fully support the b58 or to have better defined maps and clear explanations for each table and its axis and z value, cause now its only guessing game and trial and error, and it seems people don’t like to share information in this platform, ft86 was much better even with ecutek they used to provide end users with the ability to custom tune which they dont for b58
 

ColonelAdama

Well-Known Member
First Name
Adam
Joined
Jan 30, 2023
Threads
2
Messages
1,433
Reaction score
1,646
Location
Greenville, SC
Car(s)
2023 Absolute Zero Supra 3.0 Premium MT, 2015 GTI
6MT is underrated but its mostly because ots are not perfected yet, if mhd can work with its customers we would get much further with the platform.
I assure you they have no interest in this after trying for the last month.
 

PowerGetter

Well-Known Member
First Name
Randall
Joined
Feb 26, 2024
Threads
14
Messages
275
Reaction score
566
Location
Long Beach, California
Car(s)
24' Supra 3.0 MT... the Orange one
I assure you they have no interest in this after trying for the last month.
This is true -- I've reached out to them as well. They reply, but are not receptive of the data and suggest, in their own words; "there's no known issues". Even when presenting them with logs.
 

TheGreenNut

Member
First Name
Shaun
Joined
Jun 5, 2025
Threads
0
Messages
20
Reaction score
15
Location
Newark, DE
Website
www.instagram.com
Car(s)
A91 MT BRG Hazelnut Supra
as someone looking into MHD Plus and with an ECU out being unlocked. I'm curious as to what the shortcomings of the MHD OTS maps are? I didn't see much as I searched through the forums on issues/shortcomings with MT's
 

razorlab

Well-Known Member
First Name
Bryan
Joined
Oct 2, 2021
Threads
29
Messages
8,568
Reaction score
16,797
Location
Hudson Valley, NY
Car(s)
Not a Corvette.
im waiting for standalone ecus to fully support the b58 or to have better defined maps and clear explanations for each table and its axis and z value, cause now its only guessing game and trial and error, and it seems people don’t like to share information in this platform, ft86 was much better even with ecutek they used to provide end users with the ability to custom tune which they dont for b58
Zero reason for a standalone with these modern MG1 DME's unless you are at a high level of pro motorsports and are looking for more robust data telematics.

I wonder if there is a self-tuning thread on this forum?
 

Eastwood

Well-Known Member
Joined
Dec 20, 2022
Threads
11
Messages
702
Reaction score
962
Location
SoCal
Car(s)
2023 Toyota GR Supra 3.0 Premium - Stratosphere
Zero reason for a standalone with these modern MG1 DME's unless you are at a high level of pro motorsports and are looking for more robust data telematics.

I wonder if there is a self-tuning thread on this forum?
Standalone ECU? Just another excuse not to send out to Femto or AutoTuner.
 

QTR FMS

Well-Known Member
First Name
Fahad
Joined
Nov 4, 2025
Threads
4
Messages
52
Reaction score
24
Location
Qatar
Car(s)
2024 6MT
Zero reason for a standalone with these modern MG1 DME's unless you are at a high level of pro motorsports and are looking for more robust data telematics.

I wonder if there is a self-tuning thread on this forum?
the self tuning thread doesnt cover everything needed, for example i have raised all limiters but i still cant get 205 load at below 4000 rpm im limited to 160 then it goes up to 195 in mid range. even though i enabled mhd boost celling and set boost by gear to 19 psi im limited to 16-18psi target boost in most of the range.

The dynamic corrections are not clear if it's a transient retard or if there is a different logic applied.

while tuning i realized that the compressor table is more important to dial in before the wdgc otherwise you wont be able to control the overboost since the compressor table is basicaly the x-axis for wgdc table.

there are many things the thread is lacking, it covers the basics, but not enough to make a quality tune. this is why i said earlier it seems most people dont like to contribute in this forum, i see the effort you are putting but i dont see anyone else sharing quality informations. compared to ft86 this platform is way behind, it requires more individuals to contribute.
 

razorlab

Well-Known Member
First Name
Bryan
Joined
Oct 2, 2021
Threads
29
Messages
8,568
Reaction score
16,797
Location
Hudson Valley, NY
Car(s)
Not a Corvette.
the self tuning thread doesnt cover everything needed, for example i have raised all limiters but i still cant get 205 load at below 4000 rpm im limited to 160 then it goes up to 195 in mid range. even though i enabled mhd boost celling and set boost by gear to 19 psi im limited to 16-18psi target boost in most of the range.

The dynamic corrections are not clear if it's a transient retard or if there is a different logic applied.

while tuning i realized that the compressor table is more important to dial in before the wdgc otherwise you wont be able to control the overboost since the compressor table is basicaly the x-axis for wgdc table.

there are many things the thread is lacking, it covers the basics, but not enough to make a quality tune. this is why i said earlier it seems most people dont like to contribute in this forum, i see the effort you are putting but i dont see anyone else sharing quality informations. compared to ft86 this platform is way behind, it requires more individuals to contribute.
So you want a standalone because you don't want to put the work into understanding the MG1 DME?

Also, if you use the MHD+ options, everything you are struggling with above gets MUCH easier.
 

ColonelAdama

Well-Known Member
First Name
Adam
Joined
Jan 30, 2023
Threads
2
Messages
1,433
Reaction score
1,646
Location
Greenville, SC
Car(s)
2023 Absolute Zero Supra 3.0 Premium MT, 2015 GTI
as someone looking into MHD Plus and with an ECU out being unlocked. I'm curious as to what the shortcomings of the MHD OTS maps are? I didn't see much as I searched through the forums on issues/shortcomings with MT's
https://datazap.me/u/coloneladama/log-1771531155?log=0&data=2-3-6-17-33-34-35-36-37-38&solo=2

pretty big shortcomings... here's shift behavior you can expect. Don't worry, MHD says you can always just "shift better" or use NLS (no lift shift). Its not their job to make a map that works with MTs, its your job to change how you drive.
1771531454992-hj.webp


serious knock and 10+ psi overboosts are totally fine and need no improvements, don't worry the limp mode does reset after 20 minutes or so.
 

ColonelAdama

Well-Known Member
First Name
Adam
Joined
Jan 30, 2023
Threads
2
Messages
1,433
Reaction score
1,646
Location
Greenville, SC
Car(s)
2023 Absolute Zero Supra 3.0 Premium MT, 2015 GTI
the self tuning thread doesnt cover everything needed, for example i have raised all limiters but i still cant get 205 load at below 4000 rpm im limited to 160 then it goes up to 195 in mid range. even though i enabled mhd boost celling and set boost by gear to 19 psi im limited to 16-18psi target boost in most of the range.
clutch protection limiter tables. Ask @razorlab nicely and he may help you define ;)

and yes, skip the compressor table stuff. Use MHD+ WGDC base override and PID override, its very straightforward "classic" tuning strategy. I had better drivability than OTS even on my base map.
Sponsored

 
Last edited:
 








Top