PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Speed Density question

Old Aug 26, 2010 | 02:52 PM
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Default Speed Density question

do you run OL or CL? I'm thinking for a street car CL would be best with NA.
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Old Aug 26, 2010 | 03:02 PM
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I run open loop speed density because I like the throttle response and flexibility.

But, I think closed loop is probably best for most applications - usually, you are going to get better fuel mileage with CL.

With that being said, most setups are perfectly fine with MAF CL as well.
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Old Aug 26, 2010 | 06:20 PM
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I run CL, just thought it would be nice to have cover my butt for any little changes in weather, gas, etc....

I turned CL off a couple of times and my AFR is still 14.3-15.1 when I am running OL.
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Old Aug 26, 2010 | 07:15 PM
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Semi-open loop using EFILive's custom operating system... you can pick which RPM vs MAP cells use STFTs to trim to stoich.
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Old Aug 26, 2010 | 08:36 PM
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another question, how is the best way to nail down the VE table when it seems it's a moving target I'm chasing?

I log avgs in my histogram but surely there is a better way.
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Old Aug 26, 2010 | 11:27 PM
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I try to do all my logs at the same time of day etc with the car fully warmed up to keep atmospherics consistant. I also filter the data quite heavily to keep the transient errors to a minimum.
Once the VE table is dialled in with this method, any deviation can be attributed to other factors & the necessary tables tweaked.
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Old Aug 27, 2010 | 05:32 AM
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If your VE table is a moving target, then you have something else going on... You are in OL for tuning right? And have STFT for idle set to disable? Clear all learned trims before logging... a couple passes on the table should bring it right in.
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Old Aug 27, 2010 | 10:58 AM
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Originally Posted by BLK02WS6
If your VE table is a moving target, then you have something else going on... You are in OL for tuning right? And have STFT for idle set to disable? Clear all learned trims before logging... a couple passes on the table should bring it right in.
what I mean is if you look at your histogram you are logging averages. If you look at the highs and lows you can see the swing. I guess what I'm asking is can that swing be reduced? LTFT have been turned off long time ago and cleared and I am in OL.

Last edited by printmanjackson; Aug 27, 2010 at 01:03 PM.
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Old Aug 27, 2010 | 11:56 AM
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Originally Posted by BLK02WS6
If your VE table is a moving target, then you have something else going on... You are in OL for tuning right? And have STFT for idle set to disable? Clear all learned trims before logging... a couple passes on the table should bring it right in.
I have EFI live also, and run COS5 in Simi-OL and love the way the car responds, You will get a better shot at hitting your VE table close to 1.00 if you use a wide band O2.

Last edited by Randy WS6; Aug 27, 2010 at 12:08 PM.
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Old Aug 27, 2010 | 01:00 PM
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Originally Posted by Randy WS6
I have EFI live also, and run COS5 in Simi-OL and love the way the car responds, You will get a better shot at hitting your VE table close to 1.00 if you use a wide band O2.
I don't think HPT has that option to run semi-OL.

I agree, I log in Lambda = 1.00 with a WB.
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Old Aug 27, 2010 | 01:39 PM
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Originally Posted by printmanjackson
I don't think HPT has that option to run semi-OL.

I agree, I log in Lambda = 1.00 with a WB.
you can, you just have to use PE TPS % = 0 but it's not as good as EFILive sounds.
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Old Aug 27, 2010 | 05:11 PM
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Originally Posted by printmanjackson
what I mean is if you look at your histogram you are logging averages. If you look at the highs and lows you can see the swing. I guess what I'm asking is can that swing be reduced? LTFT have been turned off long time ago and cleared and I am in OL.
As you correct it using the averages, it will make smaller swings... It also helps if you make smooth throttle transitions while you are logging. It's kind of an aquired feel to do it and get good data quickly. And after tuning so many cars, you get to know what the VE should look like and how to get it right quickly... Don't know if HPTuners has filters, but they can help to filter out data from quick throttle movements and such...
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Old Aug 27, 2010 | 09:25 PM
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thanks, I'm not using any filters but I'll try that. How many hits per cell would be good data?
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Old Aug 27, 2010 | 09:53 PM
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at least 20 or so
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Old Aug 29, 2010 | 08:39 PM
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Yeah you usually will get close, but never at 100%
Get it as close as you can then, flip it in closed loop.
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