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SD tuning upper rpm

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Old Sep 25, 2010 | 06:35 PM
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Default SD tuning upper rpm

As soon as my 2 bar MAP arrives.............I've got to start working on my speed density tune for my H/C blower car
. A couple of questions;
1. Shouldn't I just remove my MAF completely?
2. Since I've got my 4000rpm and less pretty close (been MAF tuning) would there be any issue with using STIFs (react quickly) from 4000 up to around 5500 if I "ease" up to it without going into boost? Due to WB scaling in HP., my WB is close, but It's not EXACT, so I'm debating which technique to use.
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Old Sep 25, 2010 | 07:51 PM
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Originally Posted by BOTTLE ROCKET
As soon as my 2 bar MAP arrives.............I've got to start working on my speed density tune for my H/C blower car
. A couple of questions;
1. Shouldn't I just remove my MAF completely?
2. Since I've got my 4000rpm and less pretty close (been MAF tuning) would there be any issue with using STIFs (react quickly) from 4000 up to around 5500 if I "ease" up to it without going into boost? Due to WB scaling in HP., my WB is close, but It's not EXACT, so I'm debating which technique to use.
1. Throw away the MAF
2. You need to do it with a WB, you could get away with easing up to 5500rpm in CL with low load, but that's not going to help you with the high (more important) load cells where you will be running richer than 14.7.
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Old Sep 25, 2010 | 08:43 PM
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I know it is definitely best with a wideband, but getting the offset right at both low AND high AFR range, has just been impossible for me. It's obviously tough for a LOT of guys based on massive amount of post I've read on the subject.
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Old Sep 25, 2010 | 10:56 PM
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Originally Posted by BOTTLE ROCKET
I know it is definitely best with a wideband, but getting the offset right at both low AND high AFR range, has just been impossible for me. It's obviously tough for a LOT of guys based on massive amount of post I've read on the subject.
Can't say I've ever had a problem with offsets. That's a hardware limitation with the gear your using. I'm using a PLX with serial data right into my V2. Digital doesn't make errors.
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Old Sep 26, 2010 | 07:06 AM
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Sorry; Probably wasn't clear enough
The offset I am referring to is to make the wideband read correctly in the HPTuners scanners. As fast as everything happens going WOT at say 3500 (2-3 secs and it's over) there's just no way to observe and react fast enough (like I can in my wife's bolt-on car) to prevent any issues (lean melt down)
I have battled with getting the offset (like apparently MANY more users) exact, but never do get it perfect at both ends.
If I tune VE with STFTs and get close before working on the WOT stuff, I just thought it might help.
This is my first SD tune, and it just makes me nervous to hear of all of the issues with the BE tables not kicking in, etc, etc.
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Old Sep 26, 2010 | 08:18 AM
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Originally Posted by BOTTLE ROCKET
Sorry; Probably wasn't clear enough
The offset I am referring to is to make the wideband read correctly in the HPTuners scanners. As fast as everything happens going WOT at say 3500 (2-3 secs and it's over) there's just no way to observe and react fast enough (like I can in my wife's bolt-on car) to prevent any issues (lean melt down)
I have battled with getting the offset (like apparently MANY more users) exact, but never do get it perfect at both ends.
If I tune VE with STFTs and get close before working on the WOT stuff, I just thought it might help.
This is my first SD tune, and it just makes me nervous to hear of all of the issues with the BE tables not kicking in, etc, etc.
No you were clear. Your referring to how the scanner utilises the 5v signal. With Digital Comms this isn't an issue as the actual Lambda value is given to the scanner not a voltage so there is nothing to scale. Just Free Air Cal the WB and away you go.

On the speed of things happening, I get where your coming from but we all have to deal with that for street tuning. Ways to help are to find a steep hill. Drag the brakes. Use a Dyno. I've dialled my VE in fine just driving normally without applying external loads like mentioned. My software does tune VE for me automatically so I don't have to rush it. But still the same applies even when you have to do it manually. You just need lots of hits in the cells.
Don't be to concerned about leaning off. Fatten your VE first and dial it down rather than up to put yourself at ease with that concern.
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Old Sep 26, 2010 | 12:23 PM
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Thanks Mecca

In the tutorial on SD, TO START, they take the present VE from your original table (limit at 105) and paste it to the new two bar, then take the last line (105) and multiply by 1.25 and paste it on the last VE line in the two bar, and interpolate between the two. Is 1.25 enough for a blown (10 psi, 650+rwhp) set up, or should I go a little higher for safety?
Thanks
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Old Sep 27, 2010 | 11:41 PM
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Originally Posted by BOTTLE ROCKET
Thanks Mecca

In the tutorial on SD, TO START, they take the present VE from your original table (limit at 105) and paste it to the new two bar, then take the last line (105) and multiply by 1.25 and paste it on the last VE line in the two bar, and interpolate between the two. Is 1.25 enough for a blown (10 psi, 650+rwhp) set up, or should I go a little higher for safety?
Thanks
I'd got with 1.50
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