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Old 06-01-2004, 10:14 PM   #1
cdvma
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Default UTEC injector scaling thoughts

I was just thinking...would it make more sence to scale the injectors and make small adjustments to the fuel map or to just make gross adjustments to the fuel map? Talking about injectors 2x the size of stock.

Modifying the MAF voltage quite a bit would bring the stock ECU into a lower load site...but does that really matter since the stock ECU is only controling low load sites anyway? With a low OLF crossover it shouldn't matter.

There is something I'm not quite sure of the operation in the UTEC and that is: does altering the injector scaling parameter modify the MAF voltage like editing the fuel map would but simply on a global scale? So in that case (if its true) it doesn't matter which method of tuning is used.

If anyone could chime in that would be great.

-Chris
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Old 06-02-2004, 06:23 AM   #2
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I was asking the same questions, and didn't get a real good answer. Here is what I did. I modded some stock injectors to flow 630cc at 43psi (yes they have been flow tested). I am running the stg4 map and set my injector scaling to 630. I have had to do quite a bit of work to the stock txs map to get all my fuel trims and such inline. It seams to work out really nice, and I have my fleu trim all at 0, and I almost have the crossover bucking completely gone. My guess is if you know what the injectors are flowing, use that for your scale, and mod the fuel map to dial it in.

Russ
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Old 06-02-2004, 09:15 AM   #3
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my understanding (which could be wrong) is that when you use injector scaling, it takes the fraction of stock/current injectors and multiplies it by the value in the background fuel map in each load site. the map modifications you make just make % changes on top of that. so theoretically, it doesnt matter which route you take, but one may be more convenient to you, and there is always the fractional differences (values of significance) between the two.
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Old 06-02-2004, 10:34 AM   #4
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The injector scaling did NOT modify the MAF voltage in ver. 4.1. I don't know how it worked, but the mod MAF voltage was the same as the input voltage in OL, even with very large injectors scaled. This worked nice, because the ECU's timing was a lot closer to what it should be. 4.2 does modify the voltage with the injector scaling.
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Old 06-02-2004, 01:04 PM   #5
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Quote:
Originally posted by Zackbo
The injector scaling did NOT modify the MAF voltage in ver. 4.1. I don't know how it worked, but the mod MAF voltage was the same as the input voltage in OL, even with very large injectors scaled. This worked nice, because the ECU's timing was a lot closer to what it should be. 4.2 does modify the voltage with the injector scaling.
This isn't really true. In 4.1 the injector scaling only scaled the hard throttle fueling(10-100% columns) while the injector scaling in 4.2 scales the whole map(0-100%). Either way you go(having really low numbers or scaling the injectors a lot), it is just like removing fuel from the map and the modified maf will decrease compared to the real maf voltage the higher the cc is for injector scaling.

peace
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Old 06-02-2004, 01:17 PM   #6
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Here is a 4.1 log:

5050 +10.8 4.2 103 70 00 rich +12.9 54.9 +23.9 +0.2 400.00 4.2
5096 +12.5 4.3 103 80 00 rich +13.8 57.2 +24.0 +0.2 400.00 4.2
5167 +14.3 4.3 103 90 00 rich +15.4 57.1 +24.0 +0.2 400.00 4.3
5184 +15.7 4.2 103 90 00 rich +16.0 81.4 +24.0 +0.2 400.00 4.3
5299 +15.7 4.3 103 80 00 rich +15.5 81.4 +24.0 +0.2 400.00 4.3
5393 +15.9 4.3 104 80 00 rich +16.4 81.4 +24.0 +0.4 400.00 4.3
5491 +15.3 4.3 103 80 00 rich +16.3 81.4 +24.0 +0.3 400.00 4.3
5583 +15.3 4.3 103 80 00 rich +16.6 81.4 +24.0 +0.3 400.00 4.3
5659 +15.1 4.3 103 80 00 rich +16.4 81.4 +24.0 +0.4 400.00 4.3
5727 +14.3 4.3 103 70 00 rich +17.5 81.4 +24.0 +0.5 400.00 4.4
5797 +14.1 4.3 102 70 00 rich +17.4 81.4 +24.6 +0.5 400.00 4.4
5847 +13.9 4.3 103 80 00 rich +17.8 81.4 +24.7 +0.6 400.00 4.3
5889 +13.9 4.3 103 80 00 rich +18.4 81.4 +24.5 +0.7 400.00 4.3
5995 +14.3 4.3 103 80 00 rich +17.8 81.4 +25.0 +0.8 400.00 4.4
6060 +13.7 4.4 103 70 00 rich +18.4 81.4 +25.0 +0.8 400.00 4.4
6150 +13.9 4.4 103 70 00 rich +18.7 81.4 +25.0 +0.8 400.00 4.4
6242 +14.5 4.3 103 80 00 rich +19.1 81.4 +25.0 +0.8 400.00 4.4
6207 +14.7 4.3 103 80 00 rich +19.2 81.4 +25.0 +0.7 400.00 4.4
6313 +15.1 4.3 103 80 00 rich +21.9 81.4 +25.0 +0.7 400.00 4.4
6361 +14.7 4.4 71 70 00 rich +21.8 87.9 +25.0 +0.7 400.00 4.3


And here is a 4.2 log:


7 +4.5 3.6 104 10 00 rich +34.3 25.4 +21.7 -3.6 350.00 2.8
3992 +6.6 3.7 104 30 00 rich +31.3 29.4 +21.0 -3.4 350.00 2.8
4065 +8.8 3.9 104 40 00 rich +29.5 33.0 +21.4 -3.1 350.00 3.0
4208 +11.0 3.9 103 60 00 rich +26.6 36.0 +19.3 -1.2 350.00 3.1
4312 +13.3 4.0 104 70 00 rich +25.3 39.2 +19.0 -1.3 350.00 3.1
4391 +15.3 4.0 104 80 00 rich +24.4 40.5 +19.0 -1.3 350.00 3.2
4535 +17.0 4.1 103 90 00 rich +24.0 42.0 +19.4 -1.2 350.00 3.2
4547 +17.4 4.1 103 80 00 rich +23.7 44.6 +20.4 -1.3 350.00 3.2
4755 +18.2 4.1 103 80 00 rich +24.4 44.2 +20.2 -2.6 350.00 3.2
4721 +18.4 4.2 103 90 00 rich +24.5 47.3 +21.2 -1.2 350.00 3.3
4830 +18.2 4.2 103 90 00 rich +25.5 45.7 +21.4 -2.4 350.00 3.3


Both of these logs are using OLF with the injectors scaled to 850.

Somehow, in 4.1, they modified the OL fuel map w/o modifying the MAF voltage. I'm sure Nathan can verify this for me.

Last edited by Zackbo; 06-02-2004 at 01:23 PM.
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Old 06-02-2004, 01:57 PM   #7
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Interesting. So in 4.2 it doesn't matter any. My map is already tuned FWIW I was just curious if it would offer any bennefit to retune using the injector scaling and not having such large negative values in the fuel map (-14s). It seems as if we need a TurboXS answer.
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Old 06-02-2004, 05:08 PM   #8
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In version 4.1 the injector size was only used in the calculation of the injector on time (i.e. the 10% to 100% columns). In version 4.2 the injector size and stock injector size are used for both the open loop fuelling injector on time (i.e. the 10% to 100% columns) plus they are used to recalibrate the MAF signal (i.e. the closed loop region).

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Old 06-02-2004, 05:51 PM   #9
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Quote:
Originally posted by hippy
This isn't really true. In 4.1 the injector scaling only scaled the hard throttle fueling(10-100% columns) while the injector scaling in 4.2 scales the whole map(0-100%). Either way you go(having really low numbers or scaling the injectors a lot), it is just like removing fuel from the map and the modified maf will decrease compared to the real maf voltage the higher the cc is for injector scaling.

peace
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Old 06-02-2004, 06:39 PM   #10
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I have used both methods.

Setting the injector scaling and tuning from that point seems to limit the hesitation effect that people sometimes run into.

Both methods result in more consitant AFR's as long as you have OLF enabled.

I tuned my classic MAF modification map on top of the OLF with no injector scaling. I have no issues with it. When I tune a map from scratch I always zero the fuel map and start with injector scaling. I then make small MAF modifications in the standard way.
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Old 06-03-2004, 12:53 AM   #11
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Since putting in my STI pink injectors, my car starts hard both cold and hot, CEL flashes and it runs rough for about 5s before it smooths out. Am I stuck with this or is there a way to fix it. The UTEC manual completely ignores this little issue.

I'm using 4.2 with injector scaling set to 550. It doesn't appear to be straight forward to determine if I'm too rich or too lean because the O2 sensor does not register until a few seconds after startup.
Thanks.
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Old 06-03-2004, 02:37 AM   #12
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Quote:
Originally posted by Blennophobic
Since putting in my STI pink injectors, my car starts hard both cold and hot, CEL flashes and it runs rough for about 5s before it smooths out. Am I stuck with this or is there a way to fix it.
No this is not normal.

Changing the injectors and applying the correct values in the UTEC will allow the car to start and idle like stock.

You should perhaps recheck your injector installation.

regards
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Old 06-03-2004, 12:03 PM   #13
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Quote:
Originally posted by TurboXS (Pete)
No this is not normal.

Changing the injectors and applying the correct values in the UTEC will allow the car to start and idle like stock.

You should perhaps recheck your injector installation.

regards
Pete
(TurboXS)
Thanks for the reply Pete. I'm sure my injectors are installed fine as I was quite careful... they installed snugly and still rotated easily after the rail was tightened down. What else could be wrong with the install?

I'm pretty sure it's a fuel mgmt problem. Is there a procedure to follow for tuning the injector scaling for a smooth idle?

Steve.
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Old 06-03-2004, 12:38 PM   #14
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Not sure with Sti injectors, but I know for a fact that peeps with modded stock injectors have to put + #'s in the 0% column to get their LTFT's in order. Up to +10 This is with 850 in the injector scaling parameter. I was getting misfire Cel's until I did this.
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Old 06-03-2004, 12:42 PM   #15
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I've run it both ways - it really makes no difference at all. As far as hesitation or bucking issues, just work your timing and fuel map right at the crossover, and avoid any huge steps. I have none, but I admit to spending a fair number of hours tuning it out.

I would say use the scaling feature, because it makes small changes much more effective. It took a full point of fuel to move my AFR .1 before scaling, now it's closer to .1:.1.

-Sean
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Old 06-03-2004, 01:26 PM   #16
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Quote:
Originally posted by Blennophobic


I'm pretty sure it's a fuel mgmt problem. Is there a procedure to follow for tuning the injector scaling for a smooth idle?

Steve.
Are you using the new stage 4 parameters off of our website? What are your 0% idle fuel values?



-Nathan
www.turboxs.com
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Old 06-03-2004, 02:43 PM   #17
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Quote:
Originally posted by big_adventure
I've run it both ways - it really makes no difference at all. As far as hesitation or bucking issues, just work your timing and fuel map right at the crossover, and avoid any huge steps. I have none, but I admit to spending a fair number of hours tuning it out.
As I mentioned before, I'm already tuned. No hesitation or bucking issues running modded stock injectors and no injector scaling.
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Old 06-04-2004, 12:03 AM   #18
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Quote:
Originally posted by nmyeti
Are you using the new stage 4 parameters off of our website? What are your 0% idle fuel values?



-Nathan
www.turboxs.com
Nathan, yes I'm using the latest stg 4 parameters from the website. Is there anything contained in the parameters other than the injector scaling number that would affect start and idle?

The 0% fuel column is now all zero's. I started with your base stg 4 map that had, I think, -2's in the 0% column at idle which made the car run worse.

Should I just try experimenting with the injector scaling number?

Steve.
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Old 06-05-2004, 01:19 PM   #19
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Changed injector scaling to 565 and it seemed to improve starting quite a bit, but is still not quite right. Still looking for suggestions on how to zero in on the exact injector scaling.
Thanks,
Steve.
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Old 06-05-2004, 01:42 PM   #20
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It's very difficult to tune the 0% column without an obd2 scan tool. I consider scaling a convenience feature. Unless you're using a base map tuned for a specific setting, just pick something reasonable and tune the details in the fuel map.
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