BM3: Stage 2 with out DP?

[tanzm4_]

How "recommend" is it to have down pipes with stage 2. BM3 clearly has stated that it isn't required and looking around on here there are mixed feelings. I don't really drive at WOT all the time so the minor increase in heat should be ok, I mean there's only like 2-3% increase over Stage 1. Might as well go Stage 2 right? *

Any input would be appreciated

[DanMpower]

Originally Posted by stealth4

How "recommend" is it to have down pipes with stage 2. BM3 clearly has stated that it isn't required and looking around on here there are mixed feelings. I don't really drive at WOT all the time so the minor increase in heat should be ok, I mean there's only like 2-3% increase over Stage 1. Might as well go Stage 2 right? *

Any input would be appreciated

I say do it, I'm a firm believer the stock downpipes are not bottlenecks for the stock turbos. You will probably gain a bit of midrange torque and possibly slightly better spool time but I don't think it's worth the trade-off for extra rasp.

[M 4 FUN]

From pro tuning freaks.

[rborane]

I would keep it on stage 1. Majority of the gains are in stage 1 anyways. I have Downpipes and still run stage 1 91 octane as I didn't notice a big difference between stage 2, and want to keep the power still somewhat usable and safe from spun crank hub. Especially if you are on 91 octane, just use stage 1 map. GTS map is a great map as well, very linear.

Also - like others have said, 5oz of boostane or 2-3 gallons of E85 will help a lot with ACN91 gas.

[Redacre]

The default Stage 2 map has very aggressive burbles and that can shorten the life of your stock cats. But I really don't think that's like something you need to worry about for 10s of ks of miles. And you can of course change the burbles in customization options or even turn them off.

OP -- have you upgraded your tires? I went stage 2 with downpipes but on the stock continentals it was just too much power and so I'm running the GTS map until these burn off I can upgrade to MPSS or something similar.

[RElias21]

Originally Posted by Redacre

The default Stage 2 map has very aggressive burbles and that can shorten the life of your stock cats. But I really don't think that's like something you need to worry about for 10s of ks of miles. And you can of course change the burbles in customization options or even turn them off.

OP -- have you upgraded your tires? I went stage 2 with downpipes but on the stock continentals it was just too much power and so I'm running the GTS map until these burn off I can upgrade to MPSS or something similar.

Some newb Questions.

I'm currently on stage 1 93.

I'm in the class of people who dislike the burbles. If I go Stage 2 and keep OEM burble settings or turn them off, is it then safe with stock DP's. I guess, what I'm asking is whether it's the burbles that require DPs?

Also, how does the GTS map compare to the Stage 1 93 map?

Thanks.

[tom @ eas]

Originally Posted by stealth4

How "recommend" is it to have down pipes with stage 2. BM3 clearly has stated that it isn't required and looking around on here there are mixed feelings. I don't really drive at WOT all the time so the minor increase in heat should be ok, I mean there's only like 2-3% increase over Stage 1. Might as well go Stage 2 right? *

Any input would be appreciated

Catless DPs are required for S2.

Use better fuel if you want to make more power. Our 91 is garbage lately.

[tanzm4_]

Originally Posted by rborane

I would keep it on stage 1. Majority of the gains are in stage 1 anyways. I have Downpipes and still run stage 1 91 octane as I didn't notice a big difference between stage 2, and want to keep the power still somewhat usable and safe from spun crank hub. Especially if you are on 91 octane, just use stage 1 map. GTS map is a great map as well, very linear.

Also - like others have said, 5oz of boostane or 2-3 gallons of E85 will help a lot with ACN91 gas.

Are you currently using the ACN map and adding splashes of e85? With blending e85 does it really matter which map I use, ACN or not?

[tanzm4_]

Originally Posted by Redacre

The default Stage 2 map has very aggressive burbles and that can shorten the life of your stock cats. But I really don't think that's like something you need to worry about for 10s of ks of miles. And you can of course change the burbles in customization options or even turn them off.

OP -- have you upgraded your tires? I went stage 2 with downpipes but on the stock continentals it was just too much power and so I'm running the GTS map until these burn off I can upgrade to MPSS or something similar.

So I just picked up a CPO M4 which has a set of fresh PSS on them. On my last m4 I was running Stage 1 on PSS as well and had a little trouble putting the power down but then got PS4S and it was a huge difference. So planning do that as well.

Also plan on keeping the OEM zcp burbles, not too much of a fan of the bm3 burbles.

[tanzm4_]

Originally Posted by tom @ eas

Catless DPs are required for S2.

Use better fuel if you want to make more power. Our 91 is garbage lately.

Tom could you explain why you feel they're required and why BM3 says they're recommended.

With our shitty gas in CA, do you recommend topping off with a few gallons of e85? Does it matter ACN map or not?

[tom @ eas]

Originally Posted by stealth4

Tom could you explain why you feel they're required and why BM3 says they're recommended.

With our shitty gas in CA, do you recommend topping off with a few gallons of e85? Does it matter ACN map or not?

OEM cats are simply too restrictive.

ACN map should be used for California. If you want to use the non-ACN 91 map, bump up the octane with a gallon or two of E85 (on a full tank) or keep a can of Torco handy.

In SoCal, we have some 76 stations around with 100 octane at the pump that can be mixed in.

[tanzm4_]

Originally Posted by tom @ eas

OEM cats are simply too restrictive.

ACN map should be used for California. If you want to use the non-ACN 91 map, bump up the octane with a gallon or two of E85 (on a full tank) or keep a can of Torco handy.

In SoCal, we have some 76 stations around with 100 octane at the pump that can be mixed in.

Got it that seems reasonable. Thanks for sharing.

Would you say there are any power differences using the ACN map over regular? If I get the ACN map would it be a good idea to top off with e85 at opportunity? Or would be ok if I get the regular map and occasionally top off with e85?

[rborane]

Originally Posted by stealth4

Are you currently using the ACN map and adding splashes of e85? With blending e85 does it really matter which map I use, ACN or not?

I alternate between the normal stage 1 91 octane map and the GTS map. With the stage 1 91 map I will add 4-5 ounces of boostane to increase octane a bit, and definitely feel the engine runs smoother and stronger. Sometimes I don't use boostane, and my car still runs fine, but I don't really ever beat on it and only occasionally really will get on it.

GTS map I usually just run 91. We don't have full E85 in AZ and only a handful of stations carry E54 which is why I just order a bottle of boostane from amazon. You will be fine with the normal 91 map and if you have access to E85 throw a couple gallons in to help!

[MpoweredLife]

Originally Posted by Redacre

The default Stage 2 map has very aggressive burbles and that can shorten the life of your stock cats. But I really don't think that's like something you need to worry about for 10s of ks of miles. And you can of course change the burbles in customization options or even turn them off.

OP -- have you upgraded your tires? I went stage 2 with downpipes but on the stock continentals it was just too much power and so I'm running the GTS map until these burn off I can upgrade to MPSS or something similar.

I think the forced induced burbles are absolutely ridiculous. If the car didn't come like that, just leave it be. I think it's the ultimate way to look like a kook/d-bag, unless Op likes that sort of attention. Lame attempt from ptf to create more fanboys.

[tanzm4_]

Originally Posted by MpoweredLife

I think the forced induced burbles are absolutely ridiculous. If the car didn't come like that, just leave it be. I think it's the ultimate way to look like a kook/d-bag, unless Op likes that sort of attention. Lame attempt from ptf to create more fanboys.

Agreed, initially on my base M4 I was hoping those induced burbles would create the ZCP overrun/burbles but I was disappointed. Now with a ZCP I don't have to mess with that

[chewbakam4]

Originally Posted by Redacre

The default Stage 2 map has very aggressive burbles and that can shorten the life of your stock cats. But I really don't think that's like something you need to worry about for 10s of ks of miles. And you can of course change the burbles in customization options or even turn them off.

OP -- have you upgraded your tires? I went stage 2 with downpipes but on the stock continentals it was just too much power and so I'm running the GTS map until these burn off I can upgrade to MPSS or something similar.

They’re pretty mild to me but you can adjust them whatever way on any map even turn them off. ACN literally has California in the name being if you search here when maps were put out with ACN meaning Arizona, California and Nevada and warm piss quality 91 octane there LOL

[Redacre]

The default stage 2 map was literally setting off the car alarms in my parking garage and I still have the stock midpipe and muffler lol

Switched to the GTS map and don't have any complaints. Turned off cold start, GTS roar, and reduced the aggression a little bit. Haven't had a neighbor complain since then. Did a track day with it before the quarantine and enjoyed the performance boost over the stock map, although it doesn't come close to the stage 2 power.

[M 4 FUN]

I run stage 2 with stock downpipes. I have 20% reduced torque and it's perfect. No problems whatsoever.
I can floor it in second gear and almost Always have full traction. Sometimes it brakes loose around 5000 rpm. Much easier to drive, i have better Control of the car. I also deleted all the fake crap on the car like burbles, rev matching, Active sound and autostart. Now i can drive my car like i want it.

[RElias21]

Originally Posted by M 4 FUN

I run stage 2 with stock downpipes. I have 20% reduced torque and it's perfect. No problems whatsoever.
I can floor it in second gear and almost Always have full traction. Sometimes it brakes loose around 5000 rpm. Much easier to drive, i have better Control of the car. I also deleted all the fake crap on the car like burbles, rev matching, Active sound and autostart. Now i can drive my car like i want it.

What made you decide to run Stage 2 with 20% reduction rather than just run Stage 1?

Any benefit over Stage 1 at that point?

[ntg44]

Originally Posted by RElias21

What made you decide to run Stage 2 with 20% reduction rather than just run Stage 1?

Any benefit over Stage 1 at that point?

Stage 2 has a higher torque peak, with more high RPM torque than stage 1, so when you run 20% reduction on stage 2, the tune cuts 20% from the peak torque of the tune, not the entire rev range, so you'll have a flatter torque curve for longer as you approach redline. The torque eventually tapers, but later than stage 1 since the high RPM torque is higher.

A simple way to understand it is look at the dyno sheet of stage 1 vs 2 on the same sheet. For a 20% reduction, multiply the peak torque of stage 2 by 80% and draw a straight horizontal line on the sheet at that 80% value in MS Paint. You'll see the torque remains constant at that level until the high RPM taper. You'll notice that stage 1 torque drops at an earlier RPM than stage 2, and pushing that taper off as far right as possible (which means at as high of an RPM as possible) gives the tune a more consistent feel of power delivery for longer.

Running torque reduction this way, you don't get that midrange torque explosion that's most likely going to cut throttle from traction control, followed by a huge dropoff after ~5500 RPM. I notice this on the stock base model tune as well. The stock tune has more of a flat hp curve than a flat torque curve, which means the torque is dropping off significantly as redline is approached. And I absolutely do feel it, for me it's not desirable. For my preference, the stock midrange torque is perfect, so if I had a tune, I'd put on stage 2 with x% reduction down to stock mid range output, just so I can get the benefits of the consistent torque delivery to almost near redline. Tunes are much more than just about peak numbers, and the benefit of BM3 reduction is you can basically tune how you want the pull to feel, which is awesome.

[RElias21]

Originally Posted by ntg44

Stage 2 has a higher torque peak, with more high RPM torque than stage 1, so when you run 20% reduction on stage 2, the tune cuts 20% from the peak torque of the tune, not the entire rev range, so you'll have a flatter torque curve for longer as you approach redline. The torque eventually tapers, but later than stage 1 since the high RPM torque is higher.

A simple way to understand it is look at the dyno sheet of stage 1 vs 2 on the same sheet. For a 20% reduction, multiply the peak torque of stage 2 by 80% and draw a straight horizontal line on the sheet at that 80% value in MS Paint. You'll see the torque remains constant at that level until the high RPM taper. You'll notice that stage 1 torque drops at an earlier RPM than stage 2, and pushing that taper off as far right as possible (which means at as high of an RPM as possible) gives the tune a more consistent feel of power delivery for longer.

Running torque reduction this way, you don't get that midrange torque explosion that's most likely going to cut throttle from traction control, followed by a huge dropoff after ~5500 RPM. I notice this on the stock base model tune as well. The stock tune has more of a flat hp curve than a flat torque curve, which means the torque is dropping off significantly as redline is approached. And I absolutely do feel it, for me it's not desirable. For my preference, the stock midrange torque is perfect, so if I had a tune, I'd put on stage 2 with x% reduction down to stock mid range output, just so I can get the benefits of the consistent torque delivery to almost near redline. Tunes are much more than just about peak numbers, and the benefit of BM3 reduction is you can basically tune how you want the pull to feel, which is awesome.

Just to be clear, when you say 20% torque reduction, are you talking about boost reduction by gear? if so, did you reduce it in every gear?

[ntg44]

Originally Posted by RElias21

Just to be clear, when you say 20% torque reduction, are you talking about boost reduction by gear? if so, did you reduce it in every gear?

Yes that's the feature. Oddly named, but the question was finally answered a while back in another thread. I'm stock, but that's the behavior of the feature.