93/98 base vs. 93/98 base high load

Discussion of tuning specific to MAZDASPEED6/MAZDASPEED Atenza/Mazda 6 MPS vehicles

93/98 base vs. 93/98 base high load

by karspa » December 3rd, 2019, 9:03 am

Anyone else compared basetune and highload tune both for stock 6 mps?

I don't get why basetune seems to requests higher load than highload tune on very top end (6500rpm). Maybe I missed some limiter but to me it looks that both tunes are gearbox limited and limit is actually higher for basetune...

So what am I missing?

There is also slight differences in ignition timing which makes me wonder which (base or high load) should I actually use?
 
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Re: 93/98 base vs. 93/98 base high load

by mituc » December 3rd, 2019, 9:32 am

The gearboxes on these cars are very strong, there is no limit imposed by those, and the limits of the clutch are somewhere well past 2.0 load in the mid range.

The reason why the base tune targets (or can target) more load past 5500rpm compared to the high load is because it heats soaks less the intercooler and turbo in the high torque RPM range.
However, the high load tune compensates with a bit more aggressive timing (1-1.5 degrees) in exactly the same range where in the base tune more load is targeted.

My suggestion is to go straight for the high load if you know you have decent gas in your area. Yet you can flash both and see which one you like more, even though the differences between them are basically non-existent when the car is used in normal conditions.
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Re: 93/98 base vs. 93/98 base high load

by karspa » December 3rd, 2019, 10:14 am

Ok makes somewhat sense. With gearbox I was referring to gearbox limiter maps not the actual gearbox :)

Still wondering a bit how it is possible that 3MPS dyno chart shows ~20hp whp gain for high load vs. base load @ 6500rpm. Based on my experience with vag/saabs I would never expect 1 degree in timing matter really that much especially when load req is slightly smaller...
 
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Re: 93/98 base vs. 93/98 base high load

by mituc » December 3rd, 2019, 11:52 am

At these loads 1 degree of timing is about 4-6 bhp past 6000rpm. One PSI of boost will give you about as much, but combined with one degree of timing it may give you 12-15bhp.

The 20bhp gain for a 3MPS (or 6MPS, or CX7) at 6500rpm is real but compared to the factory tune which commands <1 load there. With the factory tune a 3MPS gen1 will make 250-255bhp at 5500rpm and at 6000rpm it makes about 225. At 6500 it makes 180 or so. After tuning things change quite a lot.
2008 Cosmic Blue Mazda 3MPS
Build engine + WMI + GTX3071, ~476WHP @31-32PSI
2008 Icy Blue Mazda CX7
Stock engine, intake and exhaust (YES!!), GTX2867 gen2 + Autotech HPFP, self-tuned to 320-ish BHP
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Re: 93/98 base vs. 93/98 base high load

by karspa » December 4th, 2019, 12:34 am

Thanks for replying!

Now I'm just getting even more lost... How come boost (or more imporantly airmass [g/s]) is 1 PSI higher for high load tune than base load tune if we just agreed that requested load is lower for high load tune than base load tune (@6500rpm)? Airmass for sure should be lower because load is lower (other things equal), right? If I remember correctly highload request was ~1.55 @ 6500rpm while baseload was ~1.65 @ 6500rpm. I'm not saying this makes real world difference but I would like to really understand what is happening...

Maybe I have missed some additional limiter, there is some copy paste error in gear-wise load limiters or maybe I have somehow completely wrong understanding of how this ecu works...
 
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Re: 93/98 base vs. 93/98 base high load

by karspa » December 4th, 2019, 12:59 am

just figured that if both of the tunes are requesting load significantly above what is actually possible to achieve in practice then it could explain my confusion. Requested load becomes meaningless as long as its large enough... :) E.g. actual load cannot go over 1.4 because of e.g. small turbo so there is no real difference if load request is 1.5 or 1.6. But still I don't get how come there is +20hp gain - in this case it needs to be entirely because of timing/afr.
 
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Re: 93/98 base vs. 93/98 base high load

by mituc » December 5th, 2019, 3:55 am

The +20hp gain is compared to the stock tune. Also the major difference is in peak torque, about 35-40Nm gain in the 3200-5000rpm range.
the difference between base and high load is less, more on the peak torque side.
2008 Cosmic Blue Mazda 3MPS
Build engine + WMI + GTX3071, ~476WHP @31-32PSI
2008 Icy Blue Mazda CX7
Stock engine, intake and exhaust (YES!!), GTX2867 gen2 + Autotech HPFP, self-tuned to 320-ish BHP
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Re: 93/98 base vs. 93/98 base high load

by karspa » December 5th, 2019, 4:16 am

There is +20hp for high load vs. base load @6500rpm. Gain is something like +80hp over stock at this same data point (6500rpm).

I'm referring to this chart:
https://www.versatuner.com/assets/img/dyno/versatuner-mazdaspeed3-dyno-metric.png
 
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Re: 93/98 base vs. 93/98 base high load

by mituc » December 5th, 2019, 10:06 am

The difference between the base and high load map for the 3MPS is bigger. 0.05 more requested load and 2 more degrees of timing, and most importantly the ability to hit higher load past 6k rpm due to higher wastegate duty cycle target.

Also with the 3MPS higher load is targetted across the entire rev range because it's a lighter vehicle so the overall stress on the turbo and engine (both mechanical and thermal) is smaller compared to 6MPS.

So basically a totally different situation which cannot be compared with the 6.
2008 Cosmic Blue Mazda 3MPS
Build engine + WMI + GTX3071, ~476WHP @31-32PSI
2008 Icy Blue Mazda CX7
Stock engine, intake and exhaust (YES!!), GTX2867 gen2 + Autotech HPFP, self-tuned to 320-ish BHP
VersaTuner guru
 
Posts: 881
Joined: December 17th, 2011, 2:47 pm
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