Anyone wanna give my fuel and spark tables a look over?
03-30-2010, 05:19 PM
#21
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Chris my friend used to work at a BMW and VW performance shop in startford, and he's boss is still cool with him so he gets killer deals on using the shop... In 2-3 weeks I'm gonna hit the dyno for really cheap like $50-100 for 2-3 hours... I'll ask him and see if we can rent it the whole day for cheap and tune both our cars perfectly... For vacumm, cruise and boosted cells. Are you down with OPP?
On the table you posted, why would you you want 150+kpa cells when you would most likely never see those cells? In my case at 18psi my last row should probably be like130kpa I would think...
MBT = max brake torque. You reach a point on the dyno where adding spark advance no longer adds output...the point where the output ceases increasing is MBT. You will also have generally higher spark values as RPM increases due to piston speed which is faster than the flame-speed (think of the air and fuel burning, rather than exploding).
Dyno tuning is not difficult. Go to the dyno with a fuel table that hits your AFR targets perfectly, then put load on the dyno in for each rpm column, and then focus on one load cell, then increase spark in that load cell and look at the dyno monitor to see if output in creases. Do this until you get no more increase or detonation, then back off from MBT a safe value. I'd move back 2* for a street car or 4*+ for a track car.
Use the Polski det cans and you will win at lyphe.
Dyno tuning is not difficult. Go to the dyno with a fuel table that hits your AFR targets perfectly, then put load on the dyno in for each rpm column, and then focus on one load cell, then increase spark in that load cell and look at the dyno monitor to see if output in creases. Do this until you get no more increase or detonation, then back off from MBT a safe value. I'd move back 2* for a street car or 4*+ for a track car.
Use the Polski det cans and you will win at lyphe.
.....I follow ya, it makes sense. Glad I picked up a set of the polski det cans, I'm thinkin they'll come in very handy
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03-30-2010, 05:34 PM
#24
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So really I'd probably just want to get rid of the 90kpa row since the 100kpa and 80kpa rows would define the boost/timing values for that range, right?
On the table you posted, why would you you want 150+kpa cells when you would most likely never see those cells? In my case at 18psi my last row should probably be like130kpa I would think...
On the table you posted, why would you you want 150+kpa cells when you would most likely never see those cells? In my case at 18psi my last row should probably be like130kpa I would think...
But the general idea is that if you have 80, 90 and 100 kpa rows, and the values in the 90 row are about half way in between those in the 80 and 100 rows, you can probably eliminate the 90 row. It's superfluous because of the interpolation done by MS.
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03-30-2010, 05:35 PM
#25
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hmmmm....this this calculator wacked?
**Edit - Wait a minute, I think I got where I'm off, I'm not accounting for normal atmospheric pressure....This is all starting to make sense and make me feel like an idiot, lol. This is why I bought a car that was already decently tuned
kpatopsi.jpg?t=1269984882
**Edit - Wait a minute, I think I got where I'm off, I'm not accounting for normal atmospheric pressure....This is all starting to make sense and make me feel like an idiot, lol. This is why I bought a car that was already decently tuned
kpatopsi.jpg?t=1269984882
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03-30-2010, 05:36 PM
#26
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As for the 18psi/230kpa rows...you want head room so that when you overboost, bad things don't happen. If your target boost is 230kpa and you actually hit that when its cold outside, then make your 2nd row from the top 235kpa, then set boost-cut at 240kpa.
Think of the worst possible scenario when you set it up, then tune for MBT and your **** will go wiz-bang. Then, maybe you can attract a female for the first time in your life.
Think of the worst possible scenario when you set it up, then tune for MBT and your **** will go wiz-bang. Then, maybe you can attract a female for the first time in your life.
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03-30-2010, 05:39 PM
#28
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It interpolates of course, but MBT and max spark angle are not linear in relation to rpm or kpa. If he has headroom behind MBT or detonation, then he's probably safe. When I tune John's NA Miata I'm going to put it on the ragged edge (MBT dependent)then let him decide how much he wants to back off.
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03-30-2010, 05:58 PM
#31
Make the most of your table's resolution. If you use your given resolution effectively, even an 8x8 table is plenty.
In the attached graph the black line is your target AFRs for a given engine speed. These ratios should decrease as load increases generally, with some leaner spots in your cruise cells. Anyhow, you pick those, and that's what you're trying to get your VE table to hit.
The red dots, and lines represent poorly placed load row labels, doubled up where there is linear change, and lacking where there is non-linear change.
Since MS interpolates linearly, you can pick up just the endpoints of a section where there is linearly increasing/decreasing values, and use the rest of your resolution for the areas that quickly change, such as from 100-140kPa, or from cruise to 140 or so really. Since you want to go from something near stoich (or leaner) at cruise, to about 13.8:1 at 100kpa, and then as quickly as possible to the low 12s thereafter it's best to put a lot of resolution there.
Once well into boost your AFR targets stay close to 12:1, and maybe decrease one tenth of a point for every 20kPa increase in manifold pressure. This is easy to approximate with a straight line.
The blue dots and lines show a more effective use of resolution. Both blue and red use the exact same number of points (or rows in your table), but one provides a much closer approximation of your target AFR function.
In the attached graph the black line is your target AFRs for a given engine speed. These ratios should decrease as load increases generally, with some leaner spots in your cruise cells. Anyhow, you pick those, and that's what you're trying to get your VE table to hit.
The red dots, and lines represent poorly placed load row labels, doubled up where there is linear change, and lacking where there is non-linear change.
Since MS interpolates linearly, you can pick up just the endpoints of a section where there is linearly increasing/decreasing values, and use the rest of your resolution for the areas that quickly change, such as from 100-140kPa, or from cruise to 140 or so really. Since you want to go from something near stoich (or leaner) at cruise, to about 13.8:1 at 100kpa, and then as quickly as possible to the low 12s thereafter it's best to put a lot of resolution there.
Once well into boost your AFR targets stay close to 12:1, and maybe decrease one tenth of a point for every 20kPa increase in manifold pressure. This is easy to approximate with a straight line.
The blue dots and lines show a more effective use of resolution. Both blue and red use the exact same number of points (or rows in your table), but one provides a much closer approximation of your target AFR function.
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03-30-2010, 06:28 PM
#33
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Make the most of your table's resolution. If you use your given resolution effectively, even an 8x8 table is plenty.
In the attached graph the black line is your target AFRs for a given engine speed. These ratios should decrease as load increases generally, with some leaner spots in your cruise cells. Anyhow, you pick those, and that's what you're trying to get your VE table to hit.
The red dots, and lines represent poorly placed load row labels, doubled up where there is linear change, and lacking where there is non-linear change.
Since MS interpolates linearly, you can pick up just the endpoints of a section where there is linearly increasing/decreasing values, and use the rest of your resolution for the areas that quickly change, such as from 100-140kPa, or from cruise to 140 or so really. Since you want to go from something near stoich (or leaner) at cruise, to about 13.8:1 at 100kpa, and then as quickly as possible to the low 12s thereafter it's best to put a lot of resolution there.
Once well into boost your AFR targets stay close to 12:1, and maybe decrease one tenth of a point for every 20kPa increase in manifold pressure. This is easy to approximate with a straight line.
The blue dots and lines show a more effective use of resolution. Both blue and red use the exact same number of points (or rows in your table), but one provides a much closer approximation of your target AFR function.
In the attached graph the black line is your target AFRs for a given engine speed. These ratios should decrease as load increases generally, with some leaner spots in your cruise cells. Anyhow, you pick those, and that's what you're trying to get your VE table to hit.
The red dots, and lines represent poorly placed load row labels, doubled up where there is linear change, and lacking where there is non-linear change.
Since MS interpolates linearly, you can pick up just the endpoints of a section where there is linearly increasing/decreasing values, and use the rest of your resolution for the areas that quickly change, such as from 100-140kPa, or from cruise to 140 or so really. Since you want to go from something near stoich (or leaner) at cruise, to about 13.8:1 at 100kpa, and then as quickly as possible to the low 12s thereafter it's best to put a lot of resolution there.
Once well into boost your AFR targets stay close to 12:1, and maybe decrease one tenth of a point for every 20kPa increase in manifold pressure. This is easy to approximate with a straight line.
The blue dots and lines show a more effective use of resolution. Both blue and red use the exact same number of points (or rows in your table), but one provides a much closer approximation of your target AFR function.
. I fully understand what you are explaining though. 
's table from the first page is starting to make a lot of sense
MY TABLE FOR QUICK REFERENCE:
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03-30-2010, 06:30 PM
#34
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No no.... 18psi. But that kinda has me worried now since my spark table is only going up to 210kpa....I'd say thats no good since I'm leaving it up to MS from 210kpa on...even though it does base its interpolation off of the neighboring cells...
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03-30-2010, 07:24 PM
#36
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Which would explain why my car loses power like a **** up top....My car pulls good and strong through the midrange when I'm between 10 & 15 psi. If I lay harder into the throttle it'll run pig rich (near 10:1) and there is a noticable fall off on power. Since I bought the car, I have just become accustom to shifting earlier to stay in the rpm/boost range that felt the strongest... even though I knew I should be right in the sweet spot when I was shifting
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03-30-2010, 08:48 PM
#38
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....May 1st will probably be the first weekend with things back to normal
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