Mini F56 JCW Remap
1 - 15 of 15 Posts
Joined
·
199 Posts
Given how the latest Valvetronic BMW engines operate (the easiest answer is "it's very complicated"), the AFR's will remain identical to stock, and the non-full-load fuel consumption will also be identical. Looking at Jimbo's More-BHP tune, the tuner simply raised the torque target table values at full-load. It's the easiest way to get the result, as the complicated algorithm the ECU has to manage pumping losses and torque output will still be intact. If a tuner tries to mess with most any other setting beyond the torque target table, the drivability would be absolutely ruined.
K I am getting a ECU dump off this tuner over the weekend, I am programer low level mostly .. I will try to understand it & work it out. I think its not just torque values, but you might be right. Fuel / Air Ration also fix the consumption n low excess fuel.
Joined
·
199 Posts
Ok cool, best of luck with the data dump. Given how there are already a couple flash tunes out there in EU, there are a couple of people that've already reverse engineered the code enough to get a favorable result. Just keep in mind that the way the strategy is written is a collection of formulas and only a few lookup tables. It's far different and more complicated than what most aftermarket tuners are used to looking at. Add in the Valvetronic operation and the whole thing over most [all] tuners heads.
The easiest solution would be to raise the torque target at high load. There really isn't a boost target table anymore, it's just a resultant solution of one of the formulas, of which torque target is the main factor. The piggyback boxes attenuate the MAP signal to trick the formula to give more boost. To give a very broad non-realistic idea of how the formula looks:
Actual load = ECT * IAT * oil temp * baro * TIP * MAF * TMAP * cat temp * et cetera / requested load = wastegate PWM
To change gears, AFR is a mostly separate situation, but fairly straightforward. It's going to look at all the temps and the torque output, and then position the lambda accordingly. The super quick datalogging I've done so far show the car is Lambda 1.0 most of the time. Fuel cut on no load decel of course, and then full load tapers from 1.0 at lower RPM and temps to 0.88 at higher RPM and/or temps. This is a fairly typical strategy for current closed loop WBO2 setups.
--->what do you mean by "low excess fuel"? "Fixing" the consumption sounds illogical given how incredible the OEM fueling control is. Please elaborate.
The easiest solution would be to raise the torque target at high load. There really isn't a boost target table anymore, it's just a resultant solution of one of the formulas, of which torque target is the main factor. The piggyback boxes attenuate the MAP signal to trick the formula to give more boost. To give a very broad non-realistic idea of how the formula looks:
Actual load = ECT * IAT * oil temp * baro * TIP * MAF * TMAP * cat temp * et cetera / requested load = wastegate PWM
To change gears, AFR is a mostly separate situation, but fairly straightforward. It's going to look at all the temps and the torque output, and then position the lambda accordingly. The super quick datalogging I've done so far show the car is Lambda 1.0 most of the time. Fuel cut on no load decel of course, and then full load tapers from 1.0 at lower RPM and temps to 0.88 at higher RPM and/or temps. This is a fairly typical strategy for current closed loop WBO2 setups.
--->what do you mean by "low excess fuel"? "Fixing" the consumption sounds illogical given how incredible the OEM fueling control is. Please elaborate.
Joined
·
150 Posts
Do I read that as 240 stock (1st run )
If so I think the numbers might be a bit inflated,
still a good gain all the same
Joined
·
150 Posts
Joined
·
608 Posts
So MINI are being accurate (ish) for once on the JCW power output! The R56 (well, ours was anyway) 228bhp stock on 99RON. Still not tempted to mod Hurbert just yet. He's not "my" car so I'll leave it up to the boss!
Not quite as "out" as dear Audi with my S8 (520ps stock, 582ps actual) mind you....
Not quite as "out" as dear Audi with my S8 (520ps stock, 582ps actual) mind you....
Joined
·
199 Posts
That's probably one of the most common misconceptions for enthusiasts. Wheel HP does not equal advertised [crank] HP.
Chassis dyno numbers are "wheel HP", which includes the frictional drivetrain losses. OEM's typically advertise in something closer to SAE J1349, which is essentially power at the crankshaft with all accessories hooked up. That said, some OEM's, or some engine projects, stray from this and advertise a power and torque number that would be attainable in strange circumstances [e.g. top of Pikes Peak] in order to always produce at minimum the advertised power. Under-rating engines also helps curb insurance costs and also allows the OEM to "bump" the power later in the platforms life-cycle without needing to actually change anything.
The frictional drivetrain losses is approximately 12% for most modern front engine/front drive transverse powertrains. As such, the JCW being rated at 228 HP means we should expect a correctly calibrated dyno to read about 201 wheel HP. Of course, it's very rare to come across an aftermarket shop that's had a recent dyno calibration, so what ends up being most important are the deltas. This is why before and afters are so important to quantify any change.
Joined
·
608 Posts
Thanks for that.. The EU puts a different slant on it. Advertised/stated hp of EU vehicles is crankshaft output and NOT whp. The dyno used for the R56 JCW was in a facility in Woking, UK, which I can't name but I am sure many people will guess where it was (rhymes with A-barren). Needless to say it was probably the most advanced rolling road available in 2010...
Joined
·
199 Posts
No problem.
It's worth reiterating again that the chassis dyno is just a tool, and it's easy for the untrained to use it wrong. The two takeaways here should be, always have the dyno set to SAE correction [if possible], and use the same dyno and operator for both your before and after sets. This is the best way to achieve a reasonably useful comparison where you can create a percentage delta that can be compared across dyno brands, assuming others abide by the same test procedures.
It's worth reiterating again that the chassis dyno is just a tool, and it's easy for the untrained to use it wrong. The two takeaways here should be, always have the dyno set to SAE correction [if possible], and use the same dyno and operator for both your before and after sets. This is the best way to achieve a reasonably useful comparison where you can create a percentage delta that can be compared across dyno brands, assuming others abide by the same test procedures.
1 - 15 of 15 Posts
Join the discussion
