Dynamometers are great tuning and research tools, but they do have their limitations. The primary limiting factor of a dyno is that it’s static. It tests power at the wheels while all other parts of the car are static, which is a condition you’ll never experience on any track we’r…
Eww canned tunes on track...yikes. I won't run them on the street. Typically just a throttle map and maybe an increase to load or boost targets. The worst of them removing the load based targets and just going boost.
A proper load based tune with more allowance for timing over boost should get better results with less heat. Add a gallon or two of E85 and then you may be able to do both.
If you do spike with some E85 you can bump up any of the pesky IAT/ignition modification tables. You'll get the power back.
The steady state part of tuning is easy- making power is incredibly straight forward. Can take time, depending on the number of variables that need to be dealt with, but it's not hard.
Most of the OEM calibration time is spent on starting and transients. Heck, all of the many thousands of miles driven during development is about transients.
E85 is the way!
So did these tunes not make more power on the dyno as well? Or are you saying heat soak on the track just negates the gains? You mention that the n55 is already pretty maxed out. I'm sure the MHD claimed numbers are on the highest octane- 95/102 ron and cold car, ideal day. Dipping down to 93, especially on the track if going to lose you some power. I know my s55 was pretty sensitive to heat even on a stock tune. I could see the vmax difference on long straights at Road America and when I had to fill up with 91 instead of 93 the difference was noticeable, even on a stock tune for 91, let alone pushing the poor stock turbo so hard.
Looking at the MHD numbers stage 1 vs stage 2 is 30hp and assumes an upgrade intercooler. That might be a reasonable expectation and mostly due to the intercooler. I think the biggest take away here is that the car has inadequate cooling to support more power.
Andy Hollis said:E85 is the way!
Not for Tuner it isn't :(
theruleslawyer said:So did these tunes not make more power on the dyno as well? Or are you saying heat soak on the track just negates the gains? You mention that the n55 is already pretty maxed out. I'm sure the MHD claimed numbers are on the highest octane- 95/102 ron and cold car, ideal day. Dipping down to 93, especially on the track if going to lose you some power. I know my s55 was pretty sensitive to heat even on a stock tune. I could see the vmax difference on long straights at Road America and when I had to fill up with 91 instead of 93 the difference was noticeable, even on a stock tune for 91, let alone pushing the poor stock turbo so hard.
Looking at the MHD numbers stage 1 vs stage 2 is 30hp and assumes an upgrade intercooler. That might be a reasonable expectation and mostly due to the intercooler. I think the biggest take away here is that the car has inadequate cooling to support more power.
Yeah I think that's going to be our first target: getting IAT's down. I concur with zdnet's assessment of canned tunes, but this exercise ws all about finding hurdles before we put the time and expense into doing a custom tune, and those IATs are a big hurdle. I'd love to be able to fill the thing up with corn sauce, but the SCCA says no E85 in the TT Tuner division, so we're stuck with pump 93. Once we feel like the hard parts are squared away, though, BimmerWorld has a great tuner they work with and we'll get them logged in and working on our ones and zeros.
JG Pasterjak said:Yeah I think that's going to be our first target: getting IAT's down. I concur with zdnet's assessment of canned tunes, but this exercise ws all about finding hurdles before we put the time and expense into doing a custom tune, and those IATs are a big hurdle. I'd love to be able to fill the thing up with corn sauce, but the SCCA says no E85 in the TT Tuner division, so we're stuck with pump 93. Once we feel like the hard parts are squared away, though, BimmerWorld has a great tuner they work with and we'll get them logged in and working on our ones and zeros.
Is that Epic Motorsports?
FWIW, I had great experiences using the canned Epic tune on my E46 M3 for several years. I later had them do a custom remote tune which didn't change the peak power but did pick up about 10 ft-lbs of midrange torque.
...and then later I had them do another custom tune that took ~ 80 horsepower off the top end so that I could race it in NASA ST4. :)
You can easily test intercooler capacity on the dyno - we saw the stock Mazdaspeed Miata drop 15 hp (IIRC) on back-to-back-to-back dyno runs as that factory IC heatsoaked. In fact, the dyno is GREAT for testing heat capacity simply because there is little cooling airflow.
In the article, you talked about the heat sink capacity of the intercooler. I don't think that's really what you're after - more heat capacity just gives you more time until the IC is heatsoaked. What you want is improved heat transfer from the IC to the air. That could be a more efficient core design (not necessarily heavier) or improved airflow. Just throwing a heavy IC in there for sheer mass is not the right solution.
Intercooler or airflow upgrades done right will probably help, but isn't that just a bandaid for a turbo that's now operating further and further out of its efficiency range? Great to be able to cool the charge before it hits the intake manifold, but you'll still be running very high exhaust manifold pressures, turbine inlet temperatures, compressor out temperatures, etc. Probably not an issue on the street, but for significant track use that stuff would be in the back of my head.
The stock intercooler may be enough for a more appropriately sized turbo pushing a few more pounds of boost. At what point does it make sense to make that change first?
gearheadE30 said:Intercooler or airflow upgrades done right will probably help, but isn't that just a bandaid for a turbo that's now operating further and further out of its efficiency range?
Yes.
Unfortunately, replacing the turbo would propel us into a TT division requiring sawzalls, and we really want to preserve the streetiness of this car as much as possible. So we're trying to find the most efficient band-aids possible at this point because the tiny little turbo on this thing is super efficient, but has very little headspace. We know that we're going to hit a hardcap on power pretty soon, but we're not there yet, so I think it's worth looking for what little low-hanging fruit remains.
JG, looks like you're on MHD rather than the BM3 I'm on, but do they have a "0+" tune? With BM3, as I understand it, it's basically the stock tune from the N55 M2. I'm currently running that one (N55 235i), but haven't yet been smart enough to do any back-to-back sessions on the different tunes.
It feels much more factory, but with better top end, as opposed to the canned tunes that really just feel like they threw all the boost at the bottom end so you can blow the tires off in 2nd gear and say to your buddies "Bruh look how fast my car is now, it won't even hook!"
As I'm currently losing my personal "Don't screw with the street car!" battle and have a catted downpipe on the shelf and am shopping intercoolers, this hits at just the right time.
And I know its just whatever forum algorithm, but seeing New Reader as my status cracks me up, since my subscription could have like a 5 year old by now and it wouldn't even be weird. 
RacerBowie said:JG, looks like you're on MHD rather than the BM3 I'm on, but do they have a "0+" tune? With BM3, as I understand it, it's basically the stock tune from the N55 M2. I'm currently running that one (N55 235i), but haven't yet been smart enough to do any back-to-back sessions on the different tunes.
It feels much more factory, but with better top end, as opposed to the canned tunes that really just feel like they threw all the boost at the bottom end so you can blow the tires off in 2nd gear and say to your buddies "Bruh look how fast my car is now, it won't even hook!"
As I'm currently losing my personal "Don't screw with the street car!" battle and have a catted downpipe on the shelf and am shopping intercoolers, this hits at just the right time.
MHD has a "Stage 0" but from what I can tell it's pretty much the stock tune but *maybe* with a little more aggressive ignition curve biased toward good 93. But that could be just me getting better/fresher gas. At any rate true stock and Stage 0 seemed within the margin of error.
I'm curious how your DP works out, New Reader Bowie. I think your N55 is factory rated a few hp over ours, too, isn't it? I'd be curious where that bump comes from. Whether it's just a bit more boost, or just on the overboost, or whatever. Overall I'm starting to feel like that N55 turbo is pretty maxed and all any of us are doing is playing in the margins.
We put an intercooler sprayer on a turbo Miata years ago. It's a very DIY-able thing, ours was controlled by a pressure switch - above 6 psi, it would spritz the IC every few seconds.
Coming off track after 20 minutes at Willow Springs in 100F weather, the intercooler was cool to the touch.
Might be a good way to improve the effectiveness of the IC without a lot of effort or weight. Minimum effort version: reroute the windshield washer sprayer to in front of the IC, have the driver trigger it manually on the straights. Datalog and proceed.
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