Bigpower

Slightly edited to reflect further information:

Basic Assumption is
More Air = More Power

I have heard a little about MAF voltages being maxed out and wanted to get it clear in my own mind what the max is before rescaling is needed.

On a logged run around Cadwell I was getting 4.54V but not hitting full boost on that lap - full boost normally gives me a little more.

The std ecu is scaled to 300grams/sec and have topped out at this once but generally I am around 289-292 at peak power/high revs if turbo hot and 4.68 volts i believe.

I have tried to do some digging on this and have found the following on NASOIC:
Cant be right though as that would show me at hitting aroun 380 hp ... mmm

mass(g/s)=3.5906*mafv^3-4.0038*mafv^2+2.2571*mafv-0.4089

<pre>
mafv g/s lb/min hp
2.00 16.81 2.22 22
2.05 18.33 2.42 24
2.10 19.93 2.64 26
2.15 21.62 2.86 29
2.20 23.41 3.10 31
2.25 25.30 3.35 33
2.30 27.29 3.61 36
2.35 29.38 3.89 39
2.40 31.58 4.18 42
2.45 33.89 4.48 45
2.50 36.31 4.80 48
2.55 38.85 5.14 51
2.60 41.50 5.49 55
2.65 44.28 5.86 59
2.70 47.17 6.24 62
2.75 50.19 6.64 66
2.80 53.34 7.06 71
2.85 56.62 7.49 75
2.90 60.04 7.94 79
2.95 63.59 8.41 84
3.00 67.27 8.90 89
3.05 71.10 9.41 94
3.10 75.08 9.93 99
3.15 79.20 10.48 105
3.20 83.47 11.04 110
3.25 87.90 11.63 116
3.30 92.47 12.23 122
3.35 97.21 12.86 129
3.40 102.11 13.51 135
3.45 107.17 14.18 142
3.50 112.39 14.87 149
3.55 117.79 15.58 156
3.60 123.35 16.32 163
3.65 129.09 17.08 171
3.70 135.01 17.86 179
3.75 141.10 18.67 187
3.80 147.38 19.50 195
3.85 153.84 20.35 204
3.90 160.49 21.23 212
3.95 167.33 22.14 221
4.00 174.36 23.07 231
4.05 181.58 24.02 240
4.10 189.01 25.01 250
4.15 196.63 26.01 260
4.20 204.46 27.05 271
4.25 212.50 28.11 281
4.30 220.74 29.20 292
4.35 229.20 30.32 303
4.40 237.87 31.47 315
4.45 246.76 32.65 326
4.50 255.86 33.85 339
4.55 265.19 35.09 351
4.60 274.75 36.35 363
4.65 284.53 37.64 376
4.70 294.54 38.97 390
4.75 304.79 40.32 403
4.80 315.27 41.71 417
4.85 325.99 43.13 431
4.90 336.95 44.58 446
4.95 348.16 46.06 461
5.00 359.61 47.58 476
5.05 371.31 49.12 491
</pre>

okay so far I have discovered:

1. The basic assumption of more air flow = more power given a static AFR is correct (so long as within the turbo's efficiency zone)

2. The table above isnt entirely correct as far as the right hand column is concerned as this varies with set up/turbo/afr

3. there becomes a point at which the air going in cant get out at which point charge contamination occurs resulting in Det or the ECU retarding to avoid det

4. reducing exhaust back pressure will reduce the risk of the charge contamination but cause other issues such as overboosting (fixable in ecu mapping)

5. as the standard ecu is scaled to 300 grams/sec of air flow - any excess over this will result in the ecu not have any more cells in the fuelling table to refer to and will lean out the mixture

6. the leaning out will initially cause higher performance as per scott's very detailled AFR response but will be venturing into the un-loggable as the ecu will not know the AFR

7. It would be worthwhile recaling the ecu map once 300 grams/sec peak is reached so as to retain accuracy of fuelling control

Sorry if anyone is reading this and thinking wtf but knowledge is a drug

I will keep this updated in case any others want to know the final outcome (if there ever is one)

I never use my ecu in closed loop. even at idle.

I run some very extreme afr's at times and use other devices to control det. It works very well.

It can vary as much as 50-70 hp depending on how lean i go.

The afr mixture is carfully calculated with the det control method.

ie i know i will need

xxxx cc of fuel so there for i can pull yyyy cc of fuel and replace with zzz cc of the chemical i choose to create the same cooling propeties of the xxxx afr but using less fuel and having less mixture in the combustion chamber.
This also has a knock on effect on the ign timing which needs to be altered for the new burn charactistic of the blended fuel.

The over all result is i can lean back to 13.5:1 or even 14.0:1 under full boost at any boost pressure i like. All this and also using a base fuel of pump gas 99 RON

Afr would usually be in the low 11:1 or even high 10:1

Scott

I have also today learned that the 06 ECu is scaled to 350 grams/sec - so shouldnt need to worry about rescaling for a little while yet.

How did you learn all this stuff scott - trial and error or gleening info from others?

sdminus wrote:I never use my ecu in closed loop. even at idle.

I run some very extreme afr's at times and use other devices to control det. It works very well.

It can vary as much as 50-70 hp depending on how lean i go.

The afr mixture is carfully calculated with the det control method.

ie i know i will need

xxxx cc of fuel so there for i can pull yyyy cc of fuel and replace with zzz cc of the chemical i choose to create the same cooling propeties of the xxxx afr but using less fuel and having less mixture in the combustion chamber.
This also has a knock on effect on the ign timing which needs to be altered for the new burn charactistic of the blended fuel.

The over all result is i can lean back to 13.5:1 or even 14.0:1 under full boost at any boost pressure i like. All this and also using a base fuel of pump gas 99 RON

Afr would usually be in the low 11:1 or even high 10:1

Scott

Cool stuff, this is using Ethanol right?

Lots and lots of reasearch. I also paid for tuition from people out side of the country. Then finaly lots and lots of testing and R & D. To the point were i now re tune the car every time i take it on the track.

There can be a whole world of differance between just running your car and making your car work for the conditions.

Not with ethanol but i have used a few differant chemicals and mixes to achieve differant goals.

Its not all glory. The amount of time and fuels that get wasted is simply crazy.
In the lead up to Rotorstock i was out tuning 3 or 4 times a week. using

Paid off with the results Scott. Its an interesting idea to set up the car for the weather conditions. I suppose, essentially, all you're trying to do is to make the biggest controlled bang you can....

stuartstaples wrote:Paid off with the results Scott. Its an interesting idea to set up the car for the weather conditions. I suppose, essentially, all you're trying to do is to make the biggest controlled bang you can....

Spot on stu !

Not so important here but altitude plays an important role in the tune. Ie i always find my car is richer and slower at santa pod than at SCR. Which happens to be 50mts higher than SCR.

If you can re tune on the day you achievements can be far greater.

If you can control the burn you are in a winning situation. When you look into afrs and tuning you will get blasted by loads of facts and info ( which is all relevant in its place ) The key to a good tuner is there ability to diagnose faults and dismiss false info ( when your logs lie to you ) on the move and rectify quickly.

look at my sig. This is a quote but we all know it to be true

Scott

With barometric correction and air temperature compensation you can overcome a lot of this can you not?

dynamix wrote:okay so far I have discovered:

1. The basic assumption of more air flow = more power given a static AFR is correct (so long as within the turbo's efficiency zone)

2. The table above isnt entirely correct as far as the right hand column is concerned as this varies with set up/turbo/afr

3. there becomes a point at which the air going in cant get out at which point charge contamination occurs resulting in Det or the ECU retarding to avoid det

4. reducing exhaust back pressure will reduce the risk of the charge contamination but cause other issues such as overboosting (fixable in ecu mapping)

5. as the standard ecu is scaled to 300 grams/sec of air flow - any excess over this will result in the ecu not have any more cells in the fuelling table to refer to and will lean out the mixture

6. the leaning out will initially cause higher performance as per scott's very detailled AFR response but will be venturing into the un-loggable as the ecu will not know the AFR

7. It would be worthwhile recaling the ecu map once 300 grams/sec peak is reached so as to retain accuracy of fuelling control

Sorry if anyone is reading this and thinking wtf but knowledge is a drug

I will keep this updated in case any others want to know the final outcome (if there ever is one)

okay further reading/questions etc has led my to revise assumptions:

- The MAF sensor is scaled for around 340grams/sec on my ECU - so nowhere near topping that out.
- ECUTEK Delta Dash will only show up to 300 ... wtf??
- ECUTEK Delta Dash will only show relative Boost Pressure of up to 1.27 bar even if real boost is higher
- ECUTEK Delta Dash does show correct MAP - so will have to work on that figure
- the right hand column is correct but it is American and as usual they dont work out the same as UK HP