Top-End Restriction(s)
Thread Starter
Member
Joined: Jun 2018
Posts: 130
Likes: 28
17 C63S Coupe
Top-End Restriction(s)
Hey all,
I've been looking at tunes and found that the gains generally drop off dramatically up top and are more of an increase in mid-range torque, for the S cars at least. While that's great and all, I don't love the power delivery of the "stage 1" tuned cars. I had a similar powerband on my stock turbo STI before I swapped to a 30r and it was just... not ideal for racing. It seems the turbos are running out of steam up top and freeing up airflow in and out of the turbos would be helpful, but I'm trying to avoid modifying this car too much because I went ***** to the wall on my last car and it became way too much of a track car. So for the tuners who have tested various configs, is the primary cat in the stock downpipes the biggest restriction up top? Are the turbos just maxed out? Are the intakes a limiting factor? Cooling? Would removing the secondary cats be of any significant benefit?
I've been looking at tunes and found that the gains generally drop off dramatically up top and are more of an increase in mid-range torque, for the S cars at least. While that's great and all, I don't love the power delivery of the "stage 1" tuned cars. I had a similar powerband on my stock turbo STI before I swapped to a 30r and it was just... not ideal for racing. It seems the turbos are running out of steam up top and freeing up airflow in and out of the turbos would be helpful, but I'm trying to avoid modifying this car too much because I went ***** to the wall on my last car and it became way too much of a track car. So for the tuners who have tested various configs, is the primary cat in the stock downpipes the biggest restriction up top? Are the turbos just maxed out? Are the intakes a limiting factor? Cooling? Would removing the secondary cats be of any significant benefit?
MBWorld Fanatic!
Joined: Jul 2011
Posts: 1,146
Likes: 207
2019 AMG GT R
Hey all,
I've been looking at tunes and found that the gains generally drop off dramatically up top and are more of an increase in mid-range torque, for the S cars at least. While that's great and all, I don't love the power delivery of the "stage 1" tuned cars. I had a similar powerband on my stock turbo STI before I swapped to a 30r and it was just... not ideal for racing. It seems the turbos are running out of steam up top and freeing up airflow in and out of the turbos would be helpful, but I'm trying to avoid modifying this car too much because I went ***** to the wall on my last car and it became way too much of a track car. So for the tuners who have tested various configs, is the primary cat in the stock downpipes the biggest restriction up top? Are the turbos just maxed out? Are the intakes a limiting factor? Cooling? Would removing the secondary cats be of any significant benefit?
I've been looking at tunes and found that the gains generally drop off dramatically up top and are more of an increase in mid-range torque, for the S cars at least. While that's great and all, I don't love the power delivery of the "stage 1" tuned cars. I had a similar powerband on my stock turbo STI before I swapped to a 30r and it was just... not ideal for racing. It seems the turbos are running out of steam up top and freeing up airflow in and out of the turbos would be helpful, but I'm trying to avoid modifying this car too much because I went ***** to the wall on my last car and it became way too much of a track car. So for the tuners who have tested various configs, is the primary cat in the stock downpipes the biggest restriction up top? Are the turbos just maxed out? Are the intakes a limiting factor? Cooling? Would removing the secondary cats be of any significant benefit?
Thread Starter
Member
Joined: Jun 2018
Posts: 130
Likes: 28
17 C63S Coupe
I really want to avoid that. Maybe I'll just keep the drivetrain stock if that's the case. Was hoping to get 40-50rwhp up top out of basic bolt ons, but it seems the big gains to be had are all mid-range on the stock turbos.
Super Member
Joined: Oct 2006
Posts: 556
Likes: 4
From: Berlin
2018 C63s
A tune is all you should need for that kind of gain. I don't know what kind of speeds you're trying to see, but I hit a solid indicated 322kmh on my tuned (otherwise stock) car.
I'm flash tuned, and put down 614PS (605hp) crank power. If you want to squeeze that bit extra out, you can always go DP, or take a leap and go bigger turbo... but you said you were trying to avoid that.
Edit: I should mention that the linear feeling of power building stays consistent at higher speeds. If anything the only shortcoming is that the gearing seems to fall short up top. With the new 9 speed, I would imagine that's a bit different. I'm fairly pleased with the result, but maybe it's just my tune.
I'm flash tuned, and put down 614PS (605hp) crank power. If you want to squeeze that bit extra out, you can always go DP, or take a leap and go bigger turbo... but you said you were trying to avoid that.
Edit: I should mention that the linear feeling of power building stays consistent at higher speeds. If anything the only shortcoming is that the gearing seems to fall short up top. With the new 9 speed, I would imagine that's a bit different. I'm fairly pleased with the result, but maybe it's just my tune.
Last edited by dbvolz; Oct 31, 2019 at 08:44 AM. Reason: More info
Thread Starter
Member
Joined: Jun 2018
Posts: 130
Likes: 28
17 C63S Coupe
I just ordered a Velos tune. They seem to be the only ones outside of maybe Renntech who don't crank up the boost/torque as much as possible in the mid-range to maximize gains. Nothing wrong with that, but that's not the power delivery I want. Will report back with my experience, possibly dyno results.
Senior Member
Joined: Jun 2019
Posts: 453
Likes: 91
From: DFW, Texas
2017 AMG C63
My guess is that a lot of the flash tunes heavily taper boost on the top end to keep it safe for one size fits all tune, which is what you are feeling.
Take a look at the JB4 maps: map 4and 5 do not taper boost as much on top end, but they require ethanol, meth or racegas to do it.
Take a look at the JB4 maps: map 4and 5 do not taper boost as much on top end, but they require ethanol, meth or racegas to do it.
Trending Topics
Thread Starter
Member
Joined: Jun 2018
Posts: 130
Likes: 28
17 C63S Coupe
A tune is all you should need for that kind of gain. I don't know what kind of speeds you're trying to see, but I hit a solid indicated 322kmh on my tuned (otherwise stock) car.
I'm flash tuned, and put down 614PS (605hp) crank power. If you want to squeeze that bit extra out, you can always go DP, or take a leap and go bigger turbo... but you said you were trying to avoid that.
Edit: I should mention that the linear feeling of power building stays consistent at higher speeds. If anything the only shortcoming is that the gearing seems to fall short up top. With the new 9 speed, I would imagine that's a bit different. I'm fairly pleased with the result, but maybe it's just my tune.
I'm flash tuned, and put down 614PS (605hp) crank power. If you want to squeeze that bit extra out, you can always go DP, or take a leap and go bigger turbo... but you said you were trying to avoid that.
Edit: I should mention that the linear feeling of power building stays consistent at higher speeds. If anything the only shortcoming is that the gearing seems to fall short up top. With the new 9 speed, I would imagine that's a bit different. I'm fairly pleased with the result, but maybe it's just my tune.
Thanks for the input though, much appreciated.
My guess is that a lot of the flash tunes heavily taper boost on the top end to keep it safe for one size fits all tune, which is what you are feeling.
Take a look at the JB4 maps: map 4and 5 do not taper boost as much on top end, but they require ethanol, meth or racegas to do it.
Take a look at the JB4 maps: map 4and 5 do not taper boost as much on top end, but they require ethanol, meth or racegas to do it.
Last edited by 8cd03gro; Oct 31, 2019 at 10:47 PM.
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Senior Member
Joined: Oct 2019
Posts: 381
Likes: 136
From: AZ
2018 C63S Coupe
I just ordered a Velos tune. They seem to be the only ones outside of maybe Renntech who don't crank up the boost/torque as much as possible in the mid-range to maximize gains. Nothing wrong with that, but that's not the power delivery I want. Will report back with my experience, possibly dyno results.
