Speed Density Tuning
Jul 5, 2006 | 11:19 AM
#11
Yeh I just have bad tastes for them. I got mine from a local shop, I have it in with them...I do electrical work for them and they do my maintenance. They charged me 48 bucks. They had to have it shipped here from another location, 1 day. It's all about hook ups, hence the forums, and people like yourself KB with being a big help and cool inside info like that. Cool!
Jul 5, 2006 | 12:06 PM
#12
I got mine from GMparts....only took a week. $52 shipped I think. Do you have to disable the MAF to run a 2 bar? I thought you could still run the MAF and the 2 bar just added extra scaling for fueling in boost...am I wrong?
Jul 5, 2006 | 08:51 PM
#13
We'll after speaking with Jesse at W4M I am more than convinced that I need to do this. My MAF is currently the first component after the air filter followed by the throttle body, supercharger, outlet piping, intercooler, intake piping. Even though it feels stronger than before, the response must suffer due to the the MAF being so far upstream trying to set parameters way downstream. Any more thoughts?
Jul 5, 2006 | 09:15 PM
#14
Originally Posted by 1SlowHoe
I got mine from GMparts....only took a week. $52 shipped I think. Do you have to disable the MAF to run a 2 bar? I thought you could still run the MAF and the 2 bar just added extra scaling for fueling in boost...am I wrong?
Originally Posted by TurboBerserker from a previous SD Tuning thread
Do you still use your MAF? If so is it maxed?
For *me*, speed density is better for FI, because of the increased granularity of running a 2 (or 3) bar map sensor and doubling the size of the VE table.
Does 1bar MAF tuning work for FI? Sure. Absolutely and with great success.
Here's the difference between the two:
MAF: Your VE table becomes less important when under boost. The PCM relies on the MAF reading to calculate the necessary fuel. Where this can get dangerous is if you are maxing out the MAF (pushing more air than it can read) and the PCM is fooled into thinking you have less air coming in that you actually do, and it tunes you lean.
You also have 1bar of granularity in the VE table, so you can't manually add more fuel (which is ignored after 4000rpm anyway in a MAF driven PCM) for boost, without adding the SAME amount of fuel FOR ALL BOOST LEVELS. A 1bar VE is the exact same as an NA ve table. You can effectively add fuel for boost by adding to the 105kpa column, but you then treat everything from 0 boost to your max boost to exactly the same VE settings (as found in the 105kpa column).
2BAR SD: This method ditches the MAF altogether, which means your tune must be BANG ON RIGHT. There is no MAF anymore to act as a safety net for the VE table, so 100% of the fueling for all RPMs comes from your VE settings. The benefit is that you get twice the granularity of a 1 bar tune. You can now tune for all boost and vacuum levels your engine will see (up to 2bar of course).
This means you have a column for each 5kpa of boost you add over 105kpa and can tune for boost exactly as you tune for vacuum operation. This is a more precise tune, and a tune that is more in your control than a MAF tune.
It's also 6x more work, much more fragile to ambient temp changes, mods, etc.
For *me*, speed density is better for FI, because of the increased granularity of running a 2 (or 3) bar map sensor and doubling the size of the VE table.
Does 1bar MAF tuning work for FI? Sure. Absolutely and with great success.
Here's the difference between the two:
MAF: Your VE table becomes less important when under boost. The PCM relies on the MAF reading to calculate the necessary fuel. Where this can get dangerous is if you are maxing out the MAF (pushing more air than it can read) and the PCM is fooled into thinking you have less air coming in that you actually do, and it tunes you lean.
You also have 1bar of granularity in the VE table, so you can't manually add more fuel (which is ignored after 4000rpm anyway in a MAF driven PCM) for boost, without adding the SAME amount of fuel FOR ALL BOOST LEVELS. A 1bar VE is the exact same as an NA ve table. You can effectively add fuel for boost by adding to the 105kpa column, but you then treat everything from 0 boost to your max boost to exactly the same VE settings (as found in the 105kpa column).
2BAR SD: This method ditches the MAF altogether, which means your tune must be BANG ON RIGHT. There is no MAF anymore to act as a safety net for the VE table, so 100% of the fueling for all RPMs comes from your VE settings. The benefit is that you get twice the granularity of a 1 bar tune. You can now tune for all boost and vacuum levels your engine will see (up to 2bar of course).
This means you have a column for each 5kpa of boost you add over 105kpa and can tune for boost exactly as you tune for vacuum operation. This is a more precise tune, and a tune that is more in your control than a MAF tune.
It's also 6x more work, much more fragile to ambient temp changes, mods, etc.
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