Drag/Acceleration Mods to improve ¼ mile times and unofficial track thread

[Tonkabob]

There isn't that level of precision that IAT signal manipulation, and the JB4 side logic for it isn't setup that way either. We could do more with it but have found the current logic does what we need. Make sure you have the IAT wire installed and enter a "6cyltiming" value to influence IAT. Lower values increase IAT and higher values lower IAT with the change being proportional to the current IAT. Something like a slight colder bias is probably what you need. I'd start at a 60 setting and go from there.

As I said start posting logs and I'll see what we can do to help your tuning. If we see something in the logs that indicates the need for a logic change I'm always game to customize the JB4 code.

Good to see its configurable. How do i get a iat wire? Jb4 arrives tomorrow.
I want a hotter bias for cool weather off track dragy days. We don't get full boost until 95 or 100 degrees.
For heat soaked track i think I'm good as is. Maybe try +1 psi by gear / rpm.

 

[dgDVM]

Maybe I missed it somewhere in this thread history, but what RPMs are you AWD guys able to launch at? Stock wheels? How much higher with new wheels/slicks?

 

[Terry@BMS]

Good to see its configurable. How do i get a iat wire? Jb4 arrives tomorrow.
I want a hotter bias for cool weather off track dragy days. We don't get full boost until 95 or 100 degrees.
For heat soaked track i think I'm good as is. Maybe try +1 psi by gear / rpm.

Sorry missed this post, I think I replied to you on n54tech though.

 

[Tonkabob]

Maybe I missed it somewhere in this thread history, but what RPMs are you AWD guys able to launch at? Stock wheels? How much higher with new wheels/slicks?

Its more about the amount of throttle (the ecu allows) and boost more than the rpm. Stock LC people get 2200 to 2450 and most get 1 psi tops. Most get 2800 with brake snip but 10+ psi and full throttle which easily spins AWD even on a track.
My snip has a mellow mode (gt2 weirdness) that is 2800 rpm 4-8 psi but only 40% throttle and it never spins even on the road.

 

[dgDVM]

I haven't done the brake snip yet, so maybe I don't fully understand. When you say you can get 2800, do you mean the ecu still limits it to that, or that's all the higher you can push it and the brakes still hold? I guess I'll just have to play with it to figure out the sweet spot?
If you go 10+psi and full throttle and it spins, doesn't it cut power? Seems like none would be wanting to launch like that. I also have a gt2, so we'll figure that out on mine when I get around to actually doing the snip.

 

[Tonkabob]

I haven't done the brake snip yet, so maybe I don't fully understand. When you say you can get 2800, do you mean the ecu still limits it to that, or that's all the higher you can push it and the brakes still hold? I guess I'll just have to play with it to figure out the sweet spot?
If you go 10+psi and full throttle and it spins, doesn't it cut power? Seems like none would be wanting to launch like that. I also have a gt2, so we'll figure that out on mine when I get around to actually doing the snip.

Seems people hit 2800 with full or partial pedal but if you hold it more than a second it will go higher which you DONT want to do. The 2 people that held it for 3+ seconds went up to 3500 rpm and their trannys are messed up. GT2 AWDs tend to cut throttle after 1 second of spin in any scenario - wet, dry, launch, roll.
For me the full power snip launch also guts power even if I don't spin much if any at all.
For me the lower power snip is the default and cuts the 60 by .1 but you give a little of that back as the car typically doesn't run as smooth and also opens the throttle slowly up to 20 MPH. If I sit in snipped mode and the auto off "A" light starts flashing on the dash, then I get full power mode which I don't use cause its too much to control and always bogs anyways.

 

[dgDVM]

thanks for all the info. so leaving snipped longer is what causes the full power mode on your car?
I'm just trying to figure out how these guys on here are supposedly getting 60's near 1.6 and into the 11.5s. I know the car has the potential but I'm not near there yet.

Yeah sure, driver mod might be part of it, but not that much. They're doing something different than me, and I'm hoping the brake snip is most of it? But you say only shaved .1 off 60, which is good but then you give it back? I'm jealous of these numbers lol

 

[Terry@BMS]

thanks for all the info. so leaving snipped longer is what causes the full power mode on your car?
I'm just trying to figure out how these guys on here are supposedly getting 60's near 1.6 and into the 11.5s. I know the car has the potential but I'm not near there yet.

Yeah sure, driver mod might be part of it, but not that much. They're doing something different than me, and I'm hoping the brake snip is most of it? But you say only shaved .1 off 60, which is good but then you give it back? I'm jealous of these numbers lol

The burn out switch takes you from 1.8s potential to 1.5s potential on the 60'. Doesn't seem to work great for every AWD car but has worked for most.

 

[Tonkabob]

thanks for all the info. so leaving snipped longer is what causes the full power mode on your car?
I'm just trying to figure out how these guys on here are supposedly getting 60's near 1.6 and into the 11.5s. I know the car has the potential but I'm not near there yet.

Yeah sure, driver mod might be part of it, but not that much. They're doing something different than me, and I'm hoping the brake snip is most of it? But you say only shaved .1 off 60, which is good but then you give it back? I'm jealous of these numbers lol

I went from 1.83 - 1.86s to 1.74s - 1.78s. Sometimes i get a .1 et drop sometimes only .05. It helps a little. Maybe not worth it unless you get the full power. But I'll be curious if your gt2 awd behaves the same as mine.
I'm running 11.86 lc and 11.80 snip so my car isnt slow.

 

[Tonkabob]

thanks for all the info. so leaving snipped longer is what causes the full power mode on your car?
I'm just trying to figure out how these guys on here are supposedly getting 60's near 1.6 and into the 11.5s. I know the car has the potential but I'm not near there yet.

Yeah sure, driver mod might be part of it, but not that much. They're doing something different than me, and I'm hoping the brake snip is most of it? But you say only shaved .1 off 60, which is good but then you give it back? I'm jealous of these numbers lol

Leaving the snip on and sitting in drive where the car wants to shut the motor off trigers the agressive mode. It often triggers in the staging lanes so now wait and flip the switch right before i stage.
You can't turn beast mode off except by restarting the car.

 

[Terry@BMS]

Leaving the snip on and sitting in drive where the car wants to shut the motor off trigers the agressive mode. It often triggers in the staging lanes so now wait and flip the switch right before i stage.
You can't turn beast mode off except by restarting the car.

Can't you just brake boost to a lower RPM to launch under less boost? Or use the JB4's boost by gear to lower boost potential in 1st?

 

[Tonkabob]

Can't you just brake boost to a lower RPM to launch under less boost? Or use the JB4's boost by gear to lower boost potential in 1st?

It seems to go to 2800 freely. I've tried half pedal less than 1 secomd and launched with a chirp or very little spin but throttle still cuts. Its super hard to modulate. Maybe transition to full pedal more slowly. My car also cuts throttle using lc with e30 so hitting Wills 1000nm tq limit i guess.
Boost by gear i would have to go -5 or more which would kill the rest of first gear. Its the throttle more than the boost. I have seen 8 psi in limp snip mode with less throttle and it launches smooth no spin the same as 4 psi in limp snip mode.

 

[Terry@BMS]

Give it a shot at -5psi and lets see the launch log. I might be able to reconfigure the boost by gear for a separate "launch" limiter.

 

[Przemek]

Holy seat soak, 160f starting inlet temps! Update the firmware so we have cyl 2-6 timing but I think the temps alone have you down 30-40hp. Boost is reasonable as is fueling. Timing is lower due to the higher IAT.

For the launch, any plans to do the Burger brake switch? It's a real difference maker for AWD cars.

View attachment 27915

@Terry@BMS

Terry, where can I find info about the Burger brake switch? I cannot find any info here and on your web..

 

[Terry@BMS]

Stinger Burn Out Switch DIY - N54Tech.com - International Turbo Racing Discussion

 

[dgDVM]

I'm just curious how @Kato_the_kia_stinger put down his numbers. 11.599 @ 118.77, 7.464 @93.86, 1.614
Was this just a lucky run where everything hooked up, or does he (or anyone else) have a repeatable, reliable method? I'll have to try @Tonkabob method and see how it goes. crazy numbers here:

Drag/Acceleration - The Official 1/4 mile track thread.​

 

[Tonkabob]

Give it a shot at -5psi and lets see the launch log. I might be able to reconfigure the boost by gear for a separate "launch" limiter.

I'll try it. I was out doing some testing at 80 degree IATS yesterday (not quite full boost temps) and jb4 +2 PSI, 20 PSI total, was able to reduce my 1/4s by about .05-.06 and added .3 MPH. Track temps I don't think I can add any but winter dragy should be fast - 11.4s hoping.
At 20 PSI the 1-6 timing was like synchronized swimmers but at +3 PSI and 21 PSI total, timing gets cut in unison across all cylinders. No afr change and no lagging timing so looks like a hard ECU cut limit.
Targeting higher boost during LC didn't seem to change boost at all. Hitting 1.5 PSI during LC with +0 and with +3. This is at 40% throttle where my limp snip is also 40% throttle but hits 4-8 PSI. Something else limiting boost during normal LC. 1st gear in general cant add more boost than it is already getting.

 

[Terry@BMS]

If timing is cut across all cylinders then it's not likely knock but rather something in the mapping. Anyway I'd have to see the data to offer useful advice on it.

 

[Tonkabob]

If timing is cut across all cylinders then it's not likely knock but rather something in the mapping. Anyway I'd have to see the data to offer useful advice on it.

I have an excel version but can't upload that but here is the csv. Run 7 was the +3 with timing pull.
Also seems the jb4 only does whole boost numbers. Aka 2.5 is 2.
This track has a hill and a turn so runs about .15 slow.

 

[xot1]

Isn't it bad to change maps back and forth?
The ECU needs time to readapt.