Bootmod3 S55 TQ limitation OTS tests - on STOCK and UPGRADE turbos - dynorun results

[Remonster]

Originally Posted by SeanWRT

Is my understanding correct that the boost limit isn't a constant % of boost reduction applied across the rev range, instead it works like a boost cap, as a result, the top end is less affected because boost tapers there anyway.

It looks to me 100% true that tuner/user adjustment via boost cap is much easier given way S55 OTS map is calibrated. And I think things can be very different with S63/N55/N20. Could even see the opposite.

Think of it as a torque limit, not a boost limit. Let's say your tune file makes maximum torque of 500 ft-lbs of torque and then you add a 20% torque limit, then the tune will function like normal but torque is capped at 400 ft-lbs (20% lower than 500) so anywhere in the tune that torque would go above 400, it is capped to stay at 400 instead.

[SeanWRT]

Originally Posted by Remonster

Think of it as a torque limit, not a boost limit. Let's say your tune file makes maximum torque of 500 ft-lbs of torque and then you add a 20% torque limit, then the tune will function like normal but torque is capped at 400 ft-lbs (20% lower than 500) so anywhere in the tune that torque would go above 400, it is capped to stay at 400 instead.

The S55's DME is load-based which means that it calculates how much acceleration it thinks the driver needs and then calculates how much boost it should use to hit that target (among many other variables) so this torque limit approach works extremely well.

Remonster,

I wish things work the way it should as we think. Unfortunately, 'boost limit by gear' being a torque limit based control doesn't really make sense from a tuning perspective.

Log it and see for yourself how boost is capped all the way, not the torque. To control torque directly, boost would've been unpredictable, let alone make it dead flat as shown from the log.

[Remonster]

Originally Posted by SeanWRT

Remonster,

I wish things work the way it should as we think. Unfortunately, 'boost limit by gear' being a torque limit based control doesn't really make sense from a tuning perspective.

Log it and see for yourself how boost is capped all the way, not the torque. To control torque directly, boost would've been unpredictable, let alone make it dead flat as shown from the log.

You're right that the mechanism for limiting torque ends up being boost but I was trying to conceptually explain it in a simpler way.

[Halim@HCP]

Originally Posted by Remonster

You're right that the mechanism for limiting torque ends up being boost but I was trying to conceptually explain it in a simpler way.

Basically this ECU is torque-based. It converts torque to load.
What the boost by gear is doing is limitating torque, which limits load -> boost timing etc.

[Rick448]

Originally Posted by Halim@HCP

Basically this ECU is torque-based. It converts torque to load.
What the boost by gear is doing is limitating torque, which limits load -> boost timing etc.

So, if I put the OTS stage 1 on my car, and reduce the in gear setting by 20% in first and second, and 10% in third, I won't be actually losing the potential power in those gears unless the torque limit is reached?

I am hoping to tweak the OTS Stage 1 91so that I can make the car more powerful than the CS map, but drivable in the lower gears. I guess what I am looking for is a CS map for first and second, and then a stage 1 map in the higher gears, how is that best achieved?

Cheers,

Rick

[Remonster]

Originally Posted by Halim@HCP

Basically this ECU is torque-based. It converts torque to load.
What the boost by gear is doing is limitating torque, which limits load -> boost timing etc.

Whatever you're doing, it works extremely well! I've been testing it since yesterday and am really happy with it.

Originally Posted by Rick448

So, if I put the OTS stage 1 on my car, and reduce the in gear setting by 20% in first and second, and 10% in third, I won't be actually losing the potential power in those gears unless the torque limit is reached?

I am hoping to tweak the OTS Stage 1 91so that I can make the car more powerful than the CS map, but drivable in the lower gears. I guess what I am looking for is a CS map for first and second, and then a stage 1 map in the higher gears, how is that best achieved?

Cheers,

Rick

This is actually exactly what I just did, Stage 1 ACN91 with 20% reduction for 1st and 2nd gear and 10% in 3rd gear. "CS map for 1st and 2nd and stage 1 in other gears" is exactly how I would describe it now except the top end of every gear including 1st and 2nd is still just as powerful as the normal Stage 1 tune. Try it out, I am really loving how the car feels with this exact setup. Makes it really easy to launch the car and blast through the first few gears, it's just enough torque to ride the limit of adhesion of the rear tires without excessive wheelspin but still has the big torque hit that the full Stage 1 tune gives you in higher gears.

[AllNatty]

Quick question.. I just got a catless downpipe as my only performance mod and am looking to get a Stage 2 93 Octane tune.

Is it okay to get the one with aggressive burbles that recommends a straight piped exhaust? even though I just have stock exhaust besides the downpipes?

[Halim@HCP]

[QUOTE=Remonster;24371973]Whatever you're doing, it works extremely well! I've been testing it since yesterday and am really happy with it.

[Halim@HCP]

Originally Posted by RidduLs

Quick question.. I just got a catless downpipe as my only performance mod and am looking to get a Stage 2 93 Octane tune.

Is it okay to get the one with aggressive burbles that recommends a straight piped exhaust? even though I just have stock exhaust besides the downpipes?

We recommend full exhaust for the aggressive burble version, the stage 2 93OCT OTS also provides some deep burble with catless downpipes!

[Rick448]

Originally Posted by Remonster

This is actually exactly what I just did, Stage 1 ACN91 with 20% reduction for 1st and 2nd gear and 10% in 3rd gear. "CS map for 1st and 2nd and stage 1 in other gears" is exactly how I would describe it now except the top end of every gear including 1st and 2nd is still just as powerful as the normal Stage 1 tune. Try it out, I am really loving how the car feels with this exact setup. Makes it really easy to launch the car and blast through the first few gears, it's just enough torque to ride the limit of adhesion of the rear tires without excessive wheelspin but still has the big torque hit that the full Stage 1 tune gives you in higher gears.

I have edited the map to these settings already, I will be flashing it at the weekend to try it out, I'm looking forward to that now you have confirmed that my gut feeling settings work well.

[r0wr]

Originally Posted by Remonster

Whatever you're doing, it works extremely well! I've been testing it since yesterday and am really happy with it.

This is actually exactly what I just did, Stage 1 ACN91 with 20% reduction for 1st and 2nd gear and 10% in 3rd gear. "CS map for 1st and 2nd and stage 1 in other gears" is exactly how I would describe it now except the top end of every gear including 1st and 2nd is still just as powerful as the normal Stage 1 tune. Try it out, I am really loving how the car feels with this exact setup. Makes it really easy to launch the car and blast through the first few gears, it's just enough torque to ride the limit of adhesion of the rear tires without excessive wheelspin but still has the big torque hit that the full Stage 1 tune gives you in higher gears.

I'm tying to figure out if I wanna go to stage 1 ACN or stage 1. I'm in California do it seems like the ACN is really made for us.

Sounds like you have it figured out in terms of the boost reduction though. I'm running the cs+ map with a 20 percent reduction in 1st and 2nd and it's been great but having a little more top end power would be nice.

[Remonster]

Originally Posted by r0wr

I'm tying to figure out if I wanna go to stage 1 ACN or stage 1. I'm in California do it seems like the ACN is really made for us.

Sounds like you have it figured out in terms of the boost reduction though. I'm running the cs+ map with a 20 percent reduction in 1st and 2nd and it's been great but having a little more top end power would be nice.

The top end is noticeably stronger compared to CS+. Before I played with the limits in lower gears, CS+ was my favorite map overall. Keep in mind that Stage 1 ACN91 with a 20% cut is still going to make a little more torque than CS+ with a 20% cut.

ANC91 is perfect for us in California, the regular Stage 1 91 octane map didn't pull as smoothly and actually felt a tiny bit slower. This is most likely a result of timing being pulled back in response to knock detection which isn't a problem on the map designed for our California 91 octane gas.

Originally Posted by Rick448

I have edited the map to these settings already, I will be flashing it at the weekend to try it out, I'm looking forward to that now you have confirmed that my gut feeling settings work well.

I put a lot more miles on the car in this rain we've been getting in San Diego and it performs really well. Even launching with full DSC off is totally manageable in 1st and 2nd gear, it'll spin the tires in both gears if you go full throttle but not badly enough to get insane axle hop or sideways like it does on the full tune (my car is manual and I'm using Pilot Sport 4S tires, the experience will be very different with the stock tires which are shit even with the stock tune).

[Rick448]

Originally Posted by Remonster

I put a lot more miles on the car in this rain we've been getting in San Diego and it performs really well. Even launching with full DSC off is totally manageable in 1st and 2nd gear, it'll spin the tires in both gears if you go full throttle but not badly enough to get insane axle hop or sideways like it does on the full tune (my car is manual and I'm using Pilot Sport 4S tires, the experience will be very different with the stock tires which are shit even with the stock tune).

I currently have winter tyres on here in the UK, but my summer wheels have MP4S tyres on, I have flashed to CS+ today and left it at full boost for now, it is a lovely map with a nice increase in power over the stock CS map, but still really drivable and encourages the use of higher revs. I am loving this thing

[///BMW Junkie]

Halim, apologies if this comes across as dumb question, but are these the OTS maps that come with a full map pack or custom tunes by you?

[MPOOR]

Thank you for the timesaving informative post ~!!! I reducing mine ~

[Halim@HCP]

Originally Posted by ///FASTDAD

Halim, apologies if this comes across as dumb question, but are these the OTS maps that come with a full map pack or custom tunes by you?

All testing is done on the OTS maps only!

[Rick448]

I've now flashed to the CS+ map, a nice improvement but still really drivable. I have also added cold start delete, but am not sure about that yet as it nearly stalls when driving off, I may need to up the idle rpm a little.

[chewbakam4]

You should just turn off cold start and leave that RPM setting on stock.

[Rick448]

Originally Posted by chewbakam4

You should just turn off cold start and leave that RPM setting on stock.

That's how it is at the moment.

[Remonster]

Originally Posted by Rick448

I've now flashed to the CS+ map, a nice improvement but still really drivable. I have also added cold start delete, but am not sure about that yet as it nearly stalls when driving off, I may need to up the idle rpm a little.

I have the same problem on CS+ with cold start deleted. I keep telling myself I’m going to take a log and open a support ticket but then I’ve been so happy with Stage 1 that I haven’t gotten around to it. The Stage 1 map occasionally acts a little weird right after cold start (with cold start cycle disabled) but not nearly as noticeable as what happens on the CS+ map when cold start is disabled.

[Rick448]

Originally Posted by Remonster

I have the same problem on CS+ with cold start deleted. I keep telling myself I’m going to take a log and open a support ticket but then I’ve been so happy with Stage 1 that I haven’t gotten around to it. The Stage 1 map occasionally acts a little weird right after cold start (with cold start cycle disabled) but not nearly as noticeable as what happens on the CS+ map when cold start is disabled.

I am going to live with it for a few days and see if I'm happy with it, it is literally a couple of stutters while I reverse off my drive, it just feels really agricultural. It is just soooo much better than the previous noise.

[aBMWfan]

Just a guess, but I could see another benefit of limiting the boost and torque in lower gear.

-Limiting Crank Hub wear and failure!