Tuner can't tune my cai and has given up on me.

[K4fxd]

I'm coming up with 55% increase for MAF flow on your latest log. The increase from the stock 15 MAF to a 120 MAF should be closer to 90%

When I get time I'll look over your logs and find the one with the correct 120mm Maf curve. Hopefully you can link it with the tune that it logged.

Sponsored

 

[markmurfie]

I'm coming up with 55% increase for MAF flow on your latest log. The increase from the stock 15 MAF to a 120 MAF should be closer to 90%

When I get time I'll look over your logs and find the one with the correct 120mm Maf curve. Hopefully you can link it with the tune that it logged.

It was the log with JLT and stock injectors that showed only a 50% increase.

 

[K4fxd]

It was the log with JLT and stock injectors that showed only a 50% increase.

Did I do the math wrong on the log he posted after fixing the leak?

 

[markmurfie]

Did I do the math wrong on the log he posted after fixing the leak?

Probably not. 50% vs 55% after fixing a small leak.

 

[K4fxd]

Probably not. 50% vs 55% after fixing a small leak.

Good to know I can still do some math.

Period 128.0=23.88 Lbs of air stock 17
Period 128 from his fixed log= 36.59

I get 53.2% increase.

86mm stock MAF = 43^2*PI=5805.86
120mm = 11304/5805.86= 94.5% increase

 

[K4fxd]

OP use the tune that goes with the log "(8KRPM)JLT R1"

 

[markmurfie]

OP use the tune that goes with the log "(8KRPM)JLT R1"

He has the stock injectors in. That tune needs the 47#injectors.

 

[K4fxd]

He has the stock injectors in. That tune needs the 47#injectors.

You are correct, sorry OP

 

[markmurfie]

Good to know I can still do some math.

Period 128.0=23.88 Lbs of air stock 17
Period 128 from his fixed log= 36.59

I get 53.2% increase.

86mm stock MAF = 43^2*PI=5805.86
120mm = 11304/5805.86= 94.5% increase

Im curious if when you say 128 period and not show all the period values you used in the axis, did you actually set your graph up like pictured to eliminate average error from surrounding row values? Narrow it down to just 128 as much as possible. I can't assume his tuner is using the stock MAF curve exactly. Not many tuners leave that alone like they should.

I get 49.5% increase from 24.56 to 36.72 at 128us. There may also be bias from polling speed and the cell hit amount diffence between the MAF housing sizes. Its a little low period for the stock MAF housing, only seeing transient conditions, probably got a quarter of the hits in that range.

Yup about 1/4 of the cell count for the stock intake, attached another pic of that.

 

[cbrtrx]

Good to know I can still do some math.

Period 128.0=23.88 Lbs of air stock 17
Period 128 from his fixed log= 36.59

I get 53.2% increase.

86mm stock MAF = 43^2*PI=5805.86
120mm = 11304/5805.86= 94.5% increase

It should be close to 41 lbs at 128 Period assuming everything else is calibrated correctly.

That's from actual calibrations of a few cars I've done with that intake in the past.

 

[K4fxd]

Im curious if when you say 128 period and not show all the period values you used in the axis, did you actually set your graph up like pictured to eliminate average error from surrounding row values?

I did not, just going for a general trend, not 100% accuracy. I checked 4 points and got the same general 50% increase over a stock map, then picked one to show the math.

The tune associated with the 8K log has an increase of around 99% over the stock curve so I would expect it to pull fuel.

 

[tdstuart]

@markmurfie @K4fxd
So I was using my school laptop for the tuning and I had to turn that in and was waiting till I bought a new one. Got a new laptop and finally switched back to lu47 injectors.

With stock injectors on 91 I got way better fuel economy but way worse performance. Also looked like the knock sensors were kicking in and retarding my timing a lot.

Finally switched back to lu47, running 91. Car is now pulling 10%+ fueling... no idea why. The only thing I did was rotate the bank of the injectors, other than that nothing changed from when it originally had the 47lb injectors. Really curious as to why the sudden change in fueling.

Ill try the jlt with the tune you suggested K4xd.

Here is a log of the 91 tune when it had the lu47 and a log of it after the reinstall.
https://www.dropbox.com/s/l6fx0woqx25o6pc/stock box 91 compare.hpl?dl=0
https://www.dropbox.com/s/o3bkzap3k425kkb/91 VCT 47lb stock air, 47lb reinstall.hpl?dl=0

Sponsored