Maf scaling and maxing it out

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cougar351
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Maf scaling and maxing it out

Post by cougar351 » Sat Jul 28, 2018 6:17 pm

So i have a 408w twin 61mm turbos in a 67 cougar. 80lb injectors and twin 255s. I am also spraying meth. Now I have been having a problem. I scaled everything down and at 1200 maf counts, everything is steady great 11.5 afr, but the when I bump the boost from 13 psi to 15 psi my afr is 11.5 till it gets up to 1500 maf counts and it leans out like im running out of fuel. Inj duty is at 80%, pulse width is 20-21. So i thought im out of fuel, added fuel on the tables no change at all when i get up to 1500 counts. So i added a meth nozzle and afr is now 11.0 which .5 drop then when i reach 1500 counts of maf it leans way out again. Figured if I added meth nozzle and afr stayed steady at 1500 counts then it point to something with my fuel system. Now that i have rambled on the maf is in a 3 inch pipe its a hpx-e i scaled it down so it is not seeing high voltage but can it still be maxed out does it loose resolution even if its scaled down. I mean technically I could scale it down till it never hits 4.7 volts but will it still read is my question ??
Last edited by cougar351 on Sat Jul 28, 2018 9:01 pm, edited 1 time in total.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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skunk
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Re: Maf scaling and maxing it out

Post by skunk » Sat Jul 28, 2018 7:42 pm

What ECU and tuning software are you using? Sounds like a fun car!

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Sat Jul 28, 2018 8:53 pm

Its a a9l using quarter horse with binary editor brought it to a local 1/8 mile track today and ran a 6.2 at 112 the car weights 3600 with me in it 230 pounds.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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skunk
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Re: Maf scaling and maxing it out

Post by skunk » Sun Jul 29, 2018 7:38 am

When you say 1500 MAF counts......I assume your meaning the KG/Hr? First thing comes to mind is FN037 - Airflow Max vs RPM. Did you Max this entire function to 3.90619?

Scaling the MAF is to keep you under the ~2300 kg/hr max flow the ECU will process over a 0-5 volt span. You should not be changing the voltage only the flow. If your pegging voltage, no amount of scaling is going to help you. If you are pegging that sensor....you can increase the diameter of pipe just enough to keep you in check. To answer your question about the resolution.....yes you loose resolution when you cram more flow into the same 0-5 volt span.

Realistically 80% duty on your injectors should be ok, but it's still possible your running out of fuel. For comparison a 11.1 AFR on my 306 with 42's @ 10psi is showing ~70 duty, ~18-20 ms pulse. If your injectors can't unload enough fuel into the cylinder due to valve timing events you may need larger injectors. You can try playing with the Injector timing table by either increasing the values to spray longer as the intake is closing or smaller numbers to see if you can get more fuel pulled into the cylinder when the Piston passes TDC. I don't think messing with this will help but gives you something to consider. Another simpler option is to increase the fuel pressure and retune.

I think I've rambled on enough, good luck

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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Paulie
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Re: Maf scaling and maxing it out

Post by Paulie » Sun Jul 29, 2018 1:00 pm

Also make sure your load isn't at or over 200%
1990 Mustang 5.0, HCI, Vortech S-trim, FRPP 42# inj., PMAS MH95, A9L, Moates Quarterhorse, BE/EA, Innovate LC-1.

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Sun Jul 29, 2018 8:48 pm

I just checked and my maf vs rpm is at 2.60001 I'm assuming this is my problem? My load is at 155.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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skunk
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Re: Maf scaling and maxing it out

Post by skunk » Sun Jul 29, 2018 9:10 pm

Most likely...Yes. Input the maximum value and go for drive.

Let us know how you make out.
John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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EDS50
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Re: Maf scaling and maxing it out

Post by EDS50 » Mon Jul 30, 2018 2:13 pm

If you are scaling the maf. I assume you should also be scaling the injectors. I would be curious to look at your tune if you can post it. I am also keen to learn more about your fuel system.
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Mon Jul 30, 2018 4:21 pm

so brought the car for a drive and my tune may also be a basket case because i have been changing things left and right trying to figure this out. Took it for a ride and on 17 psi my injectors are seeing 100+ duty cycle maf voltage is at 4.5 now at wot 11.8 afr with spraying 10 gph and a 6 gph nozzle which i feel like 80 pound injectors shouldnt be that high with that much meth with a 11.8 afr.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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EDS50
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Re: Maf scaling and maxing it out

Post by EDS50 » Mon Jul 30, 2018 4:31 pm

With that being said if your injector values arent scaled accordingly to the same scaling factor you used for your maf; you will experience these issues as well.
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Mon Jul 30, 2018 4:51 pm

I guess it is probably screwed up then may have to start from scratch im not sure how to attach a tune. my maf was a hpx 3 inch pipe so i took the original transfer and scaled it down to 2500 at 4.7 and then scaled the injectors 80 and 101 by the same percent....
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

cougar351
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Posts: 52
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Re: Maf scaling and maxing it out

Post by cougar351 » Mon Jul 30, 2018 5:08 pm

I am going to try to re do my injectors and maf transfer It is pretty hacked up from me just trying different things set the original transfer and original injector data to see how it goes.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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EDS50
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Re: Maf scaling and maxing it out

Post by EDS50 » Mon Jul 30, 2018 5:09 pm

You need to scale sarchg as well. I am assuming your maf is blow thru before the intercooler?
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Mon Jul 30, 2018 5:32 pm

It is blow thru after the Intercooler.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

cougar351
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Re: Maf scaling and maxing it out

Post by cougar351 » Mon Jul 30, 2018 5:35 pm

I just re did maf transfer, injector data and set cid back to orignal numbers did a quick pull and seems to be better than it was load is at 155 with 4.4 maf volts and 1800 counts, but the injectors dropped down to 70% which is nice and pulse width is now 16 vs 23. It was all good before i started going past 12 psi lol. Guess i hacked the tune.
67 cougar 408w twin 61mm turbos th400 3.08s best 1/8 mile 6.2 at 112

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EDS50
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Re: Maf scaling and maxing it out

Post by EDS50 » Mon Jul 30, 2018 5:38 pm

There you have it. Glad you figured it out.
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

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