JB4 Firmware v3.12 and 3rd gear boost limiting

[Mike@N54Tuning.com]

New v3.12 JB4_S55 firmware was posted today, along with a new tuning interface, that now includes 3rd gear boost limiting. I'm not sure how many of you spin in to 3rd on OEM turbos but with PURE S2 turbos it's a huge issue. So far using the boost limiting they've been able to get their 60-130 times down to 6.9s on a 2.5%, 7.3s on less than 1% slope, but expect to improve those times soon. This is full weight on OEM 19" rims with 265/35/19 R888s out back.

Note that while the interface says "boost limit by gear" it's actually currently programmed as "boost reduction by road speed", where 1st is under 30mph, 2nd is under 50mph, and 3rd is under 85mph. They expect to use road speed and engine speed to add a gear calculated value in a future version so we can have true boost by gear. But speaking from experience setting 1st gear to say 6.0 and 2nd to say 4.0 makes a huge improvement in off the line traction.

[TeKiZeRo]

That's pretty damn good! I am hoping they can get it to 6.5s with some more tweaks so it'll be on GT-R level (bolt-ons + E85) .

[orevah]

great news!

[Mike@N54Tuning.com]

Originally Posted by orevah

great news!

Should be some other cool things coming down the pipeline as well

Mike

[saxon]

boost by gear seems like it is a necessity on this chassis

[schnazzy]

Originally Posted by Mike@N54Tuning.com

But speaking from experience setting 1st gear to say 6.0 and 2nd to say 4.0 makes a huge improvement in off the line traction.

Mike, I have grip issues. JB4 3.13....
I think the default is 0.0 for the 3 options. So you say put 6.0 in "Max Boost 1st"? Then 4 in for 2nd?

What about 3rd?
Also, what does 6 mean? 6psi above stock?

[gtrsam]

Originally Posted by schnazzy

Mike, I have grip issues. JB4 3.13....
I think the default is 0.0 for the 3 options. So you say put 6.0 in "Max Boost 1st"? Then 4 in for 2nd?

What about 3rd?
Also, what does 6 mean? 6psi above stock?

firmware 3.13 those values are a reduction in boost. ie, 6 in 1st and 4 in 2nd means reduce boost by 6 psi and 4psi under 30mph in 1st and under 50mph for 2nd.

the new obd connector firmware is 1-3 max boost. ie, you would put 15 in first for the max boost you want to run in 1st gear. gear dependent now instead of 1st being 30mph and under

I also had mine set to 6 and 4 on firmware 3.13 but still spun. 8 and 5 probably better

[Mike@N54Tuning.com]

Originally Posted by gtrsam

firmware 3.13 those values are a reduction in boost. ie, 6 in 1st and 4 in 2nd means reduce boost by 6 psi and 4psi under 30mph in 1st and under 50mph for 2nd.

the new obd connector firmware is 1-3 max boost. ie, you would put 15 in first for the max boost you want to run in 1st gear. gear dependent now instead of 1st being 30mph and under

I also had mine set to 6 and 4 on firmware 3.13 but still spun. 8 and 5 probably better

There is no one size fit all number. Start with what I posted and if you still have traction issues increase the boost limiter. Depends a lot on tires, temp, etc. 8,5,3 is a pretty aggressive boost reduction which should eliminate most spin.

Mike

[8600RPM]

New obd2 is definetly actual max boost, not reduction anymoRe. I use 16 in 1st and 18 in 2nd .

[schnazzy]

and thus my confusion. I believe the default in 3.13 is 0 which is off and therefore I have the most boost and no reduction. I have traction issues but I don't want to reduce/set the boost in a way that hurts overall performance.

[8600RPM]

What's the confusion? In latest update you simply set what max boost ypu desire. If you want full boost you set zero (didabled)

[dmk08]

My car must suck because I dont do any boost reduction and I dont spin bad in 2nd at all. Maybe just a tiny bit then grip. Just running 295 supersports out back.

[gtrsam]

Originally Posted by schnazzy

and thus my confusion. I believe the default in 3.13 is 0 which is off and therefore I have the most boost and no reduction. I have traction issues but I don't want to reduce/set the boost in a way that hurts overall performance.

your hurting more performance by spinning. reducing boost helps if you can't hook with the right tires. I have advan ad08r tires right now and they burn through 2nd set at 5psi. I've stopped even ripping it in 1-2 at the moment bc of this. now patiently waiting for my drag radials to come in. if this doesn't work it's time for me to move on to a new platform ....I miss my gtr 1-3 gear traction

[8600RPM]

Limiting boost allows you to put power to ground. It's silky bmw didn't even do this stock, let alone trying tuned. 1st and 2nd is way faster with boost reduction

[schnazzy]

http://www.n54tech.com/forums/showth...t=30236&page=4
I am using firmware 1.3 (odb2 upgrade). For it, the number is max boost. I don't know if the other (3.13) firmware for non-odb2 configuration is the same.

Terry states 1st should be set to 15 and 2nd to 18.
http://www.n54tech.com/forums/showth...t=30236&page=3 (post #65)

[Mike@N54Tuning.com]

Originally Posted by 8600RPM

Limiting boost allows you to put power to ground. It's silky bmw didn't even do this stock, let alone trying tuned. 1st and 2nd is way faster with boost reduction

+1

Mike