Boost by Gear with OEM Logic

[John Papageorgiou]

I would get the opinion of MT tech support before switching because it might not be that much better.
That no burnouts policy is lame. Well, here are 2 other things that could help - tire pressure and camber. I run -0.5° for the drag strip (and street) in the rear and about 20 psi. You need the best contact patch you can get

Who’s MT Tech support?

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[Hammerhead13579]

Mickey Thompson Technical Support. You just call the phone number

 

[Rolls]

Would a slip angle between the front and rear wheels at a 30ms interval retarding spark on a Pid controller work or is 30ms too long? 5ms may be possible however I don't believe the abs sends data that fast.

Something I would implement if it would be used on mass. Unfortunately only a handful of people seem to go to this length so it has not had an roi to develop yet.

 

[Rolls]

Basically I want to be able to smash the throttle on the hit and not be on guard to let off and pedal it. I think as you’re suggesting if I can get it dialled in with my 3.55 gearing by the time I get to say 75mph I’ll be in 4th and full torque and maybe more consistent 60-130 runs or 100-200 km/hr runs (in Australia).

This is the problem, no burnouts allowed and the hit is strictly from 35-40 mph on non prepped race track. Power is only about 780-800 whp (whipple 3L, 3.75 pulley, LTH, E85). I run 305 x 40 x 18 e steet ss but I may go to 305 x 45 x 18 e street R. Can’t go to a 17 inch rim as I run big brakes. My diff gear is 3.55 so I could bring that down to a 3.31 but just thinking a torque by gear tune for 2nd and 3rd would help.

Torque by gear would definitely help. Or simply limiting power by spark. We have some users use the alternate fuel (normally e85 and 93) for a spark blend. So you can use the user "ethanol" select to blend 0-100% power by simply reducing spark timing in the lower rpm range where peak torque occurs at low speed. Then when you are at speed you are out of this rpm range. Simply adjust the dial to get more or less power. Can also add fuel to reduce power and keep the exhaust cool from the reduced spark.

Depends how much you need to reduce power and if by gear or simply by rpm is sufficient.

 

[John Papageorgiou]

Torque by gear would definitely help. Or simply limiting power by spark. We have some users use the alternate fuel (normally e85 and 93) for a spark blend. So you can use the user "ethanol" select to blend 0-100% power by simply reducing spark timing in the lower rpm range where peak torque occurs at low speed. Then when you are at speed you are out of this rpm range. Simply adjust the dial to get more or less power. Can also add fuel to reduce power and keep the exhaust cool from the reduced spark.

Depends how much you need to reduce power and if by gear or simply by rpm is sufficient.

When I was at 620whp I could hook in 2nd at 35 mph but now at 780-800 I even have to pedal it in 3rd a little but thank you for your input.

 

[Rolls]

Sounds more fun with 600 and less dangerous! The most fun I had was 260rwkw in a 1200kg r32 skyline. Grip galore, no boost by gear generally needed and it would steer itself straight magically on its own. The S550 tries to kill you in stock form in drag mode. I don't understand enough about suspension but I assume the wheel base difference and electronic steering is why when it spins it likes to point at the gutter and then grip. The old skyline would squat and centre up (whilst spinning, would look like a nice suspension travel plot from above) with almost no steering input.

 

[John Papageorgiou]

Sounds more fun with 600 and less dangerous! The most fun I had was 260rwkw in a 1200kg r32 skyline. Grip galore, no boost by gear generally needed and it would steer itself straight magically on its own. The S550 tries to kill you in stock form in drag mode. I don't understand enough about suspension but I assume the wheel base difference and electronic steering is why when it spins it likes to point at the gutter and then grip. The old skyline would squat and centre up (whilst spinning, would look like a nice suspension travel plot from above) with almost no steering input.

Yep on a good tyre 600 whp was fun but not quick enough mid way and back end, so trying to get a tune where I have basically 600 whp in 2nd 3rd and 800 in 4th onwards. If the stang came out AWD like GTRs and 300 pound lighter it would be an absolute monster at rolls with plenty of boost.

 

[mejohn50]

Would a slip angle between the front and rear wheels at a 30ms interval retarding spark on a Pid controller work or is 30ms too long? 5ms may be possible however I don't believe the abs sends data that fast.

Something I would implement if it would be used on mass. Unfortunately only a handful of people seem to go to this length so it has not had an roi to develop yet.

Having some sort of an accessible and adjustable traction control mechanism would be amazing. Something we could dial in on the engine side of the calibration since OEM traction control is in the ABS module or whatever. If implemented, I think the better way to do it would be to control/modify the torque request rather than just controlling spark. That way the OEM torque control can determine the best way to achieve the desired torque. Though, since you have to set the calibration up like an Ecoboost so the torque control works at WOT it would suffer from similar calibration complexities like this torque by gear.

 

[Rolls]

I would say there are less than 5 aftermarket tuners who know how to set up the torque model correctly hence the lack of enthusiasm on our side.

 

[mejohn50]

I would say there are less than 5 aftermarket tuners who know how to set up the torque model correctly hence the lack of enthusiasm on our side.

That completely makes sense.

 

[WildHorse]

So what happens when you have all the traction ? it's still limiting by gear, correct ?

 

[mejohn50]

So what happens when you have all the traction ? it's still limiting by gear, correct ?

This boost/torque by gear logic isn't a traction control mechanism that has any feedback loop so it limits torque based on the values programmed into the calibration and that's it. You set the desired torque values in the calibration and you get what you get until you change them or switch tune slots with different values programmed. It's one of many limiting factors of using the logic, but it does work and it works quite well when dialed in for the conditions.

We do not readily have access to the traction control logic in the ABS module. That is why @Rolls is discussing the implementation of a sort of traction control logic into the PCM using the data and controls we currently have available, like wheel speed and spark.

 

[gorditas]

Yep on a good tyre 600 whp was fun but not quick enough mid way and back end, so trying to get a tune where I have basically 600 whp in 2nd 3rd and 800 in 4th onwards. If the stang came out AWD like GTRs and 300 pound lighter it would be an absolute monster at rolls with plenty of boost.

What you describe is how I have my boost controller set up on my Hellion TT kit: 600, 700, 800 with a push of a button after gear changes. It's a big reason I went TT. The forward button toggles to the next set point, while the aft button returns to the low boost setting.

 

[tosha]

You set the desired torque values in the calibration and you get what you get until you change them or switch tune slots with different values programmed.

Sorry, I'm confused, is this working the way you've described or is it not? Let's say I don't care about ultimate acceleration numbers and just want a usable WOT on street tires in first 2-3 gears. Can I do static torque request limits per gear, e.g. 60% at 1st, 70% at 2nd, 85% at 3rd and 100% at 4+? How hard is that with PCMtec?

 

[mejohn50]

Sorry, I'm confused, is this working the way you've described or is it not? Let's say I don't care about ultimate acceleration numbers and just want a usable WOT on street tires in first 2-3 gears. Can I do static torque request limits per gear, e.g. 60% at 1st, 70% at 2nd, 85% at 3rd and 100% at 4+? How hard is that with PCMtec?

It works the way I described, which is why I made a thread with a video and screenshots showing it works. The very first post has most of the important information. You program in a maximum desired torque value based on gear and RPM. It’s not exactly easy to do, but I wouldn’t say it’s hard. One thing is for sure, it’s not quite as simple as just enabling the logic and setting the desired values.

It also depends on your setup. I’m not sure if it’ll work very well with turbochargers or a centrifugal. I don’t know what, if any, forced induction you may have, but that’s a factor too.

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