Strategies for Launch control on N54 6AT .Share experiences with MHD boost by gear / XHP torque limiting etc.

[rev210]

Thought I would start a thread to explore getting the humble N54 6AT off the line better on quality street rubber. To improve the 0-100 and 60ft times.

I played very briefly with boost by gear in MHD at the drag strip , with a 10psi 1st gear 14psi 2nd. But, didnt spend much time really fine tuning. It was just one run.

Given we also have XHP strategies I wonder if a mixture of these and potentially custom tuning on both fronts might produce an optimal launch /traction strategy for 6AT cars.

What are peoples experiences thus far and is it worth creating some data in the community to begin figuring out at least a framework for success?

 

[SlowE93]

Ive tried jb4 to limit boost and brake boost. Then tried anti-lag off the line. I get the same 60ft either way. Seems that with anti-lag, by the time timing kicks back in, im right back where I started as far as 60ft times go. Anti lag will launch at higher boost but less timing and lower rpm so it balances out to no anti lag, higher rpm brake boost launch, in my case anyways. I have not played too much with it as 2 broken axles from rolls scares me to launch from a dig
Oh, 2nd gear launch gives me same 60ft as well. I want to say the weight plays a big factor for my car,and the Pure DDs, but then again, as I said, havent played too much with digs.

 

[Omar@VaderSolutions]

first gear launch with tire

 

[SlowE93]

first gear launch with tire

I launch in 1st with tire(s) also.

 

[iminhell1]

2nd gear launch and just foot brake.
Indy 500's and rsrr's, both have done me many multiple low 1.8's. Cracked a couple 1.7's but every time the trans gives up, locks in gear, won't shift, etc.

The thing i've found is you have to make sure all the water is off the tires, front and rear. If you can, drive around the burnout box and back in. The little water the front picks up does make a difference.
Unfortunately most spray guys think they are filling an Olympic pool and wet everything.

I generally leave on 4-6 psi and 2nd is limited to 18. 3rd+ are 28psi.
If I try more I just push through the brakes or the trans bitches about it. I can stick more boost at the line and I know i can do a better 60'. I just need to find why the transmission is always complaining.

 

[Rob09msport]

That's only reason I think limiting with xhp and using first may be best . Ib prob can safely launch second but im scared to hurt my pd trans lol. Talk about working backwards in built myv trans to be scared to beat on it lol

 

[Omar@VaderSolutions]

I launch in 1st with tire(s) also.

i meant some sort of r compound or street slick

 

[SlowE93]

i meant some sort of r compound or street slick

Lmao,was just fuckn with you. Im on Toyo R888r also.

 

[iminhell1]

That's only reason I think limiting with xhp and using first may be best . Ib prob can safely launch second but im scared to hurt my pd trans lol. Talk about working backwards in built myv trans to be scared to beat on it lol

The couple times I've tried 1st starts, ET dropped and I didn't see any better 60'.
You have tot remember that every shift takes time, about 0.10 sec. The less you can shift the better.

And if you are spinning, a tire probably isn't going to help. It's going to hurt. And this is where I loose most ...
Think about it. A stickier tire does so due to more friction. That friction doesn't just go away after you're moving. It always takes more power to make that friction move. Meaning it takes more power to make a sticky tire get down the track at the same pace as a harder street tire. It really can be tenths differences.
If you're able to stick the 60' better and can lay all the power down, maybe you can ET better. But the 1:2 ratio really only works with similar tires, not from street to slick (-1/10th in the 1/8th = -2/10th in the 1/4).


I've tried pulling power, not with XHP and there is a point of diminishing returns. It really isn't the maximum power limit that helps. It's the boost ramp that does and getting that tuned just right is really tough. The boost by gear is a hack way and does work, but it's costing you time.
Start playing with adding boost by rpm, lower boost below 4K and ramp up from there, for 2nd.

 

[rev210]

I've tried pulling power, not with XHP and there is a point of diminishing returns. It really isn't the maximum power limit that helps. It's the boost ramp that does and getting that tuned just right is really tough. The boost by gear is a hack way and does work, but it's costing you time.
Start playing with adding boost by rpm, lower boost below 4K and ramp up from there, for 2nd.

So this is where I was interested to take the thread. What were the settings you actually used? Did you measure ?(dragy?) any effects ?

We need to build quantified data on electronic settings we can try play with to effect optimal 0-100 on street tyres on the road? Our N54 version of launch control or launch improvement.

Can we start experimenting with XHP and MHD to find some consensus on where you start for 'improving' dragy 0-100kmh(0-60mph).

Then again perhaps a real launch control is the answer fiddling/hacking the DTC settings ? Leveraging wheel speed sensors.

 

[iminhell1]

I was using "Load Target per Gear" under the MHD tab. It's not perfect, variances in how load is calculated, but it works far better than boost (load) by gear (option while flashing).

Playing in the DSC would be best, but the risk there is much higher. It's not as easy because the simple things, wheel speed, are used in multiple calculations, ABS, EDiff, yaw, etc. Ex, if you tell the car the tire is bigger or smaller (to fool or calibrate the sensor) it could really play havoc with other things, like ABS activation.
Finding that exact path that the slip control takes place would be really nice, and then if we had a good way to say how power/slip is reduced/controlled. It it a throttle cut, spark cut, fuel cut, etc; and at what rate. As it is now you hit DSC and with more power the system freaks out and just chops power. I don't like it. Only time I use it is Winter driving, because with traction on the car just goes nowhere.


I haven't dug into the coding stuff enough to know what's possible. I'd imagine it's some custom things would need adding and it's not going to be simple yes no options.


Here's a couple good ones from late 2016, second is late 2018,

 

[rev210]

Did you have the settings for load by gear to share? . Could be a base line setting we can then check on draggy to look at any time improvements.

To weigh in on load target vs boost (we dont yet know what is better) I've cut a 1.68 60ft on 285/18 AD08 R yokos to my 10.7 1/4 . 1st gear launch. That was boost by gear, I had 8-10 psi in 1st from memory, 2nd-3rd cant remember. Problem is I didnt note anything down.

We could have people draggy test baselines 0-30mph /0-60mph (60kmh/100kmh) . Then try a series of forum agreed incremental settings to see if there are improvements. So round 1 could be to change/try a group of 1st and 2nd gear load target and then boost target settings.

XHP torque limit might be something XHP themselves could make a suggestion on(they seem to tout it as a solution) ,they potentially could have a few n54s testing for them ? (Anyone want to contact them?)

Use the community to find concensus, based on any patterns of results.

We may be able to test 0-30mph to determine what launch traction improvements can occur , 1st gear vs 2nd gear also.

 

[Panzerfaust]

For the most part, the tactics to launch an N54 car is the same as has been tried and true on every other drag car. You want a 15" wheel, preferably a 28" tire (bias ply if you can swing it), and to leave in first. You shouldn't have any problem with spinning on the right tire setup. A proper suspension setup (another platforms rear drag shocks and stock springs F+R seem to work the best) along with a higher stall torque converter seem to be the most beneficial along with the tire setup. A 2 step combined with the higher stall to leave on higher boost also helps, though I dont know that a 2 step on it's own is all that beneficial without the rest unless you have a nice older TC that doesnt lock up until later, or at least I've never seen it help that much.

As for tuning specific stuff, the biggest benefit of an auto turbo car is keeping boost between gears, so I think if you're using the XHP customization module you'll likely want to adjust your shifting to prioritize keeping boost for at least 2-3,3-4 and possibly also the 1-2 shift. Itll likely take some tinkering with the TQ reduction to find what works best to balance the quicker spool (less tq reduction, slider to the right iirc) and shift time decrease (more tq reduction, slider left iirc) as well as cranking the shift time to as short as possible (although this will result in "harsher" shifts, it's a necessity for the strip.) Otherwise a custom trans tune if you can get one will be the best option by far judging by the videos I've seen, because it makes these ATs ridiculous. You'll also want to bump your shift points up to 7.2-7.3k RPM if your turbos will keep up with it.

 

[rev210]

For the most part, the tactics to launch an N54 car is the same as has been tried and true on every other drag car. You want a 15" wheel, preferably a 28" tire (bias ply if you can swing it), and to leave in first. You shouldn't have any problem with spinning on the right tire setup. A proper suspension setup (another platforms rear drag shocks and stock springs F+R seem to work the best) along with a higher stall torque converter seem to be the most beneficial along with the tire setup. A 2 step combined with the higher stall to leave on higher boost also helps, though I dont know that a 2 step on it's own is all that beneficial without the rest unless you have a nice older TC that doesnt lock up until later, or at least I've never seen it help that much.

As for tuning specific stuff, the biggest benefit of an auto turbo car is keeping boost between gears, so I think if you're using the XHP customization module you'll likely want to adjust your shifting to prioritize keeping boost for at least 2-3,3-4 and possibly also the 1-2 shift. Itll likely take some tinkering with the TQ reduction to find what works best to balance the quicker spool (less tq reduction, slider to the right iirc) and shift time decrease (more tq reduction, slider left iirc) as well as cranking the shift time to as short as possible (although this will result in "harsher" shifts, it's a necessity for the strip.) Otherwise a custom trans tune if you can get one will be the best option by far judging by the videos I've seen, because it makes these ATs ridiculous. You'll also want to bump your shift points up to 7.2-7.3k RPM if your turbos will keep up with it.

I understand what you are saying , I've probably got one of the better 60fts on non-drag radials (in 1.6s) btw (no drag suspension either). I know how to pedal the car to 1.6/1.7 at the drag strip but, doesnt translate to the street and I am doing the work. Still have consistancy issues on traction, so wondering if we can have our electronic friends take care of that for us. Afterall, our gas pedal is wireless and controlled by the dme. It is there that I am keen to investigate beyond the 'theory' of what we think will work to testing and collecting real data specifically in the electronic interventions available. XHP, MHD etc.

 

[Rob09msport]

The couple times I've tried 1st starts, ET dropped and I didn't see any better 60'.
You have tot remember that every shift takes time, about 0.10 sec. The less you can shift the better.

And if you are spinning, a tire probably isn't going to help. It's going to hurt. And this is where I loose most ...
Think about it. A stickier tire does so due to more friction. That friction doesn't just go away after you're moving. It always takes more power to make that friction move. Meaning it takes more power to make a sticky tire get down the track at the same pace as a harder street tire. It really can be tenths differences.
If you're able to stick the 60' better and can lay all the power down, maybe you can ET better. But the 1:2 ratio really only works with similar tires, not from street to slick (-1/10th in the 1/8th = -2/10th in the 1/4).


I've tried pulling power, not with XHP and there is a point of diminishing returns. It really isn't the maximum power limit that helps. It's the boost ramp that does and getting that tuned just right is really tough. The boost by gear is a hack way and does work, but it's costing you time.
Start playing with adding boost by rpm, lower boost below 4K and ramp up from there, for 2nd.

That's why xhp limiting by ft lb is better cause you will need increasing boost as rpm rise to keep same torque to ground and that's better than trying to calculate boost needed