Advice for traction mod

[N54gasm]

How does everyone get their power to the ground and keep it there? Car currently spins anything under a 80 roll. Car is a 15" rear, 275/50r15 mh street r, mfactory lsd, kw v1 coils / comp engineering shocks set to 60/40. Car squats hard, but just spins. I know street will never not have traction issues, but trying to get atleast a good 4th gear pull in lol. Currently only on 28psi on the setup, but cant turn up without some traction!

 

[carabuser]

The torque ramp might be too aggressive in the tune, if you're just setting the boost target up to 28psi and letting the turbo catch up then that would cause issues. You could soften the rate of boost target increase to reduce the shock.

 

[N54gasm]

The torque ramp might be too aggressive in the tune, if you're just setting the boost target up to 28psi and letting the turbo catch up then that would cause issues. You could soften the rate of boost target increase to reduce the shock.

Never thought about that. Ill have to hit up docvu and investigate a little on that end. Im going to get alignment checked and zero out camber in the rear and see what that does for me.

Otherwise perhaps a few bags if sand in the rear lol

 

[RTA]

What helped me was adjusting my springs to around 2hz and my altered my jrz rebound setting most of the issues you have went away.
I also have m3 and some alu suspension bits.

 

[ShocknAwe]

The torque ramp might be too aggressive in the tune, if you're just setting the boost target up to 28psi and letting the turbo catch up then that would cause issues. You could soften the rate of boost target increase to reduce the shock.

How would you do this? I have noticed that these cars hook up much better with a linear boost ramp, curious to your methods or the "correct" way.

Via WGDC Max 50-60% similar to how the IKMOS base seems to be?

Or via the Load to Torque table?

 

[carabuser]

How would you do this? I have noticed that these cars hook up much better with a linear boost ramp, curious to your methods or the "correct" way.

Via WGDC Max 50-60% similar to how the IKMOS base seems to be?

Or via the Load to Torque table?

Boost limit multiplier is perfect for this. It ramps up target based on the current airflow.

You can also do the same with timing but that is a much faster ramp. In this scenario i think boost is what is causing the traction to break.

 

[ShocknAwe]

Interesting, wouldn't have thought about that obviously but makes sense. Isn't there a BLM by gear table? I remember seeing that in my xdf I've scavenged together. How do we actually interpret the BLM scale?

Boost limit multiplier is perfect for this. It ramps up target based on the current airflow.

You can also do the same with timing but that is a much faster ramp. In this scenario i think boost is what is causing the traction to break.

 

[carabuser]

Interesting, wouldn't have thought about that obviously but makes sense. Isn't there a BLM by gear table? I remember seeing that in my xdf I've scavenged together. How do we actually interpret the BLM scale?

From memory it's actually part of the load model. It limits the target load based on the calculated airflow.

I don't know the logic behind the values in the table, the effect it has will vary depending on other tables that also influence the target load so just test it yourself starting down a stock values. You'll probably want to rescale the axis up to 500g/s.

 

[ShocknAwe]

From memory it's actually part of the load model. It limits the target load based on the calculated airflow.

I don't know the logic behind the values in the table, the effect it has will vary depending on other tables that also influence the target load so just test it yourself starting down a stock values. You'll probably want to rescale the axis up to 500g/s.

Blended the BLM by gear table with stock IKMOS values up to max 3 by higher flow 3rd gear and 4-6 and wow what a difference. Did rescale the MAF axis to something that made sense. Took off my MHD boost limit by gear too.

For the OP reference.

 

[JohnDaviz]

Could anyone explain to me how BLM calculations work?

 

[ShocknAwe]

Could anyone explain to me how BLM calculations work?

No idea but I've noticed a huge difference in setting at example 2.5 vs 2.8-3 in lower gears with no noticeable peak boost change for me (though I'm only targeting 16-18psi with my high flow head)

 

[JohnDaviz]

No idea but I've noticed a huge difference in setting at example 2.5 vs 2.8-3 in lower gears with no noticeable peak boost change for me (though I'm only targeting 16-18psi with my high flow head)

Can you describe the difference you feel?

 

[ShocknAwe]

Can you describe the difference you feel?

Boost onset is slower by seat feel and in my logs. I also set my WGDC Max to 55%. I'm trying to create a linear ramp in my logs.

I'm still adjusting the BLM by gear down. Goal is to get these tires to hook on the street in 1/2 without setting an artificial load or boost limit.

 

[ShocknAwe]

To update here I've worked down past the IKMOS stock BLM table and 1st is now at about 1.7, 2nd about 2 or so, 3rd tapered from 2.5-3, and 4-6 are at 3.0. My boost curve is now linear, and butt dyno says hp/tq ramp is more linear as we would expect with NA delivery (what I want). However, while this N53 head with HP800s don't just instantaneously blow the tires off anymore, I still seem to need an actual boost by gear control.

The BLM by gear doesn't seem to actually limit boost in a near normal range. See also: I'm still hitting 17-18 psi in first with a BLM of 1.7. stock IKMOS would be ~2.3. I seem to lose traction at around 7-8psi or SOMEWHERE along MAF 2-300 in first, and maybe 11-12psi in second. With BLM set the way it is there's a ton of warning and noise from the rear tires before they let go, so both by logs and chassis feel/feedback this experiment has worked.

TLDR;
- BLM seems to alter the slope of the boost onset curve,
- BLM doesn't seem to restrict the limit despite the name Caveat I'm targeting 16-18psi (~200 load) with the N53 head.
- I will now start tapering load by gear and WGDC fine tuning to try to address this
- Once load is addressed I believe next step will be to look at timing curves to watch for small pulls indicating low levels of traction intervention.
- not mentioned above but I also found the torque request and throttle sensitivity tables critical to usability of first gear. Probably has more to do with my 3.46 FD.

Cheers!

 

[N54gasm]

I somewhat fixed my issue at least. Better shocks helped pretty significant for me. Threw on some comp engineering shocks for a foxbody mustang on a 60/40 setting and now only spins like 60% of the time vs 100 lol

 

[N54gasm]

Scratch that. . . found out we pulled a bunch of timing mid range to help with timing. Anyone successfully run a 28" tire on a 1 series? Guessing widebody is the only way to fit em?

 

[ShocknAwe]

Scratch that. . . found out we pulled a bunch of timing mid range to help with timing. Anyone successfully run a 28" tire on a 1 series? Guessing widebody is the only way to fit em?

That would certainly help things.

I still need to do my rear widebody ...

 

[N54gasm]

Yes, but we had to decrease timing ALOT in the mid range (were on pump gas timing in mid range up until about 7k) then ramps up by 8k. Id rather try to fit a bigger tire lol. May just order a set of 28" tires and get em mounted and do some rolling to see if I can get her to fit this winter lol.

 

[ShocknAwe]

Yes, but we had to decrease timing ALOT in the mid range (were on pump gas timing in mid range up until about 7k) then ramps up by 8k. Id rather try to fit a bigger tire lol. May just order a set of 28" tires and get em mounted and do some rolling to see if I can get her to fit this winter lol.

Off topic but I love how the N54 sounds at 8k

 

[N54gasm]

Off topic but I love how the N54 sounds at 8k

100%. Love the way the n54 sounds in general. Now if only shell hook, id love her more lol