sds-map fuel values

[spork]

Well, I've read my manual sevceral times and looked a bunch in the archives but I'm having trouble figuring out how to get the correct map fuel settings on my sds. I bought it used so the baseline setting I have are from a 700hp supra with 720cc injectors. Is there an easy way (or math formula) to use to get a ballpark setting at certain areas that I then can use to plot a curve? I've got the LM-1 wideband setup and its been great on helping me get the rpm fuel stuff nailed down. I've got a pretty good timing curve nailed down too. But, frankly I'm a little nervous about getting into boost and not having a clue where I'm at for a starting point.

Here's a little info on my car if helps to figure out the numbers I need.

Fresh l28et with 7.7:1 comp., 52lbph injectors, hybrid t3/t4 turbo, spearco intercooler, 60mm tb. Need to know anything else? Please help, I'm very anxious to see boost pressures back up to 25psi. and see how much I've gained from where I was at with the stock ecu. Already, I've gained back a lot of the useability of the car. Thanks again,

 

James

[240hoke]

There are two ways to go about resetting to the stock curve.

 

I believe SDS has all the stock curves listed on there website or in the manual, so you could reset them that way.

 

You can also jump two pins on the hall sensor connection on the ECU (6 and 7 i believe) that will take you into the setup mode on the ECU and you can reset everything or change whatever you want. Ill get the exact pins to jump for you tomarrow if somebody else doesnt chime in. You could also call them.

 

I found that i didnt need to change the MAPP values on my car, i just messed with the fuel curve. But i havent gone above 18psi yet.

 

-Austin

[Scottie-GNZ]

Do a search and you will find many postings on this including some very detailed instructions and even examples.

 

The baseline number for RPM FUEL is derived by using the cylinder displacement and inj flow rate and this table.

 

[spork]

I must be confused on how this works then...I thought that those fuel values only were for use off boost (rpm fuel). And then you adjust the map values to get the proper fuel values under boost. Maybe I was misunderstanding some of the old posts I was reading. Can someone help clear things up for me then? If I adjust the rpm fuel for under boost, isn't it going to be really rich when I'm at that rpm and cruising? Just when I thought I had things figured out I'm all confused again.

 

James

 

Just looked again and came up with an old post by you (scottiegnz). This is the info I was refering to.

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Do not ever change the RPM FUEL map to add more fuel under boost. Instead, use the MANPRESS map. Whatever values are in RPM FUEL is there always. If you build RPM FUEL to compensate for boost, you will also have that fuel when you are not under boost. With MANPRESS, the values for boost will only be added when under boost. So, if you are at 4500RPMs and 10psi and running lean, do not add fuel at 4500 in RPM FUEL, add it at 10psi in MANPRESS.

 

If you are tuning for boost and adding fuel in MANPRESS then consider the following. Lets say you need to add fuel at 8psi and you increase the 8psi parameter by +3, I suggest adding +3 to every subsequent parameter. If the map causes you to run lean at 8psi, it is almost certain the same or worse will happen at 9, 10 and so on

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What I was wondering is how I know where to start the man. pressure curve...maybe I wasn't real clear before...anyways, help clear things up, would ya?

[Scottie-GNZ]

OK, since you have the RPM FUEL nailed down, then the focus will be on MANPRESS and IGN RETARD. I do them together because I do not like to increase boost without increasing fuel AND retarding timing.

 

Not sure what your IGN table has, but for starters, I like to shoot for about 23* total at 15psi boost. I get that by building an IGN curve with an initial timing of 20* at 500 and 750 then ramping up the advance curve to 38* at about 3000, then 38* for the rest of the table. Then in IGN RETARD, start by pulling out 1* at about 3psi, then ramp that up to 15* at 15psi. So, at 15psi you would have 38* full advance minus 15* retard for the 23* total.

 

For MANPRESS, there is no magic curve because there are too many variables that can affect fueling at WOT. Start off with the deault values in the map BUT start tuning for boost with the boost limited to say 6-7psi. Do not tune for boost in 1st or 2nd. Instead do it in 3rd and on an incline if possible (going up, of course ). Use the LM-1 to achieve your target A/F and if you have to adjust one way or the other, make the adjustment in MANPRESS. If you find you have to go a little richer at 7psi, then increase the numbers above 7psi also. Once you get 7psi nailed down then up the boost to 9psi, etc. Make small incremental changes like about by 3 in MANPRESS. Be patient, fine tuning a turbo car does not happen in one session. MOF, once you have 7psi nailed down, drive the car like that for a day or 2 before going to the next step. Your patience will be rewarded.

 

Hope I did not muddy the waters but there is an expectation that you understand the basics. BTW, keep in mind that the numbers I give are for starters and you should fine tune and adjust accordingly.

[Scottie-GNZ]

OK, since you have the RPM FUEL nailed down, then the focus will be on MANPRESS and IGN RETARD. I do them together because I do not like to increase boost without increasing fuel AND retarding timing.

 

Not sure what your IGN table has, but for starters, I like to shoot for about 23* total at 15psi boost. I get that by building an IGN curve with an initial timing of 20* at 500 and 750 then ramping up the advance curve to 38* at about 3000, then 38* for the rest of the table. Then in IGN RETARD, start by pulling out 1* at about 3psi, then ramp that up to 15* at 15psi. So, at 15psi you would have 38* full advance minus 15* retard for the 23* total.

 

For MANPRESS, there is no magic curve because there are too many variables that can affect fueling at WOT. Start off with the deault values in the map BUT start tuning for boost with the boost limited to say 6-7psi. Do not tune for boost in 1st or 2nd. Instead do it in 3rd and on an incline if possible (going up, of course ). Use the LM-1 to achieve your target A/F and if you have to adjust one way or the other, make the adjustment in MANPRESS. If you find you have to go a little richer at 7psi, then increase the numbers above 7psi also. Once you get 7psi nailed down then up the boost to 9psi, etc. Make small incremental changes like about by 3 in MANPRESS. Be patient, fine tuning a turbo car does not happen in one session. MOF, once you have 7psi nailed down, drive the car like that for a day or 2 before going to the next step. Your patience will be rewarded.

 

Hope I did not muddy the waters but there is an expectation that you understand the basics. BTW, keep in mind that the numbers I give are for starters and you should fine tune and adjust accordingly.

[spork]

That's basically the same exact timing curve I currently have (except mine starts at 24* but ends up in virtually the same place. As far as the map values..I was just hoping there was some way of getting close before going into boost. I suppose I can just try things with the rich knoba little on the positive side for the first low boost run and then if I'm plenty rich, zero out the knob and try again and then adjust from there. Just thought there might be a formula to get the numbers close like there was for the rpm fuel like I used when I did that. Anyways, Glad to know I'm on the right path and appreciate your help.

 

James

[Drax240z]

I'm playing with mine a bit today too... trying to dial it in for my 440cc/min injectors.

 

This is not necessarily that good of a map at present, as I've only just started building it, but you can get an idea of what the ignition values look like. The RPM fuel values are all over the place at the moment and aren't at all ideal.