Anyone wanna give my fuel and spark tables a look over? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 03-30-2010, 06:19 PM   #21
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by miataspeed2005 View Post
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?
Yeah I'm down.....let me know when you are planning to go!

Quote:
Originally Posted by Braineack View Post
Why are you giving yourself so many cruise rows on your ignition table? You pretty much have the same timing for your 100-90-80 rows, so why not combine them and give yourself better control at various boost levels...


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...


Quote:
Originally Posted by hustler View Post
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.
Thank you for the kind and direct response .....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
Cspence is offline   Reply With Quote
Old 03-30-2010, 06:28 PM   #22
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Quote:
Originally Posted by Cspence View Post
In my case at 18psi my last row should probably be like 130kpa I would think...
130kpa is only like 4.5psi....
Quote:
Glad I picked up a set of the polski det cans, I'm thinkin they'll come in very handy
I hope they do
Jeff_Ciesielski is offline   Reply With Quote
Old 03-30-2010, 06:31 PM   #23
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by Cspence View Post
Thank you for the kind and direct response .....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
I'm the ****, never forget it.
hustler is offline   Reply With Quote
Old 03-30-2010, 06:34 PM   #24
Senior Member
iTrader: (4)
 
Join Date: Jan 2008
Location: Falls Church, VA
Posts: 1,367
Total Cats: 16
Default

Quote:
Originally Posted by Cspence View Post
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...
I think you might be confused. Atmosphere is ~100 kpa. 90 and 80 kpa aren't boost, they're in vacuum. If you're running 18 psi of boooostsz that's about 225 kpa.
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.
ScottFW is offline   Reply With Quote
Old 03-30-2010, 06:35 PM   #25
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by Jeff_Ciesielski View Post
130kpa is only like 4.5psi....
I hope they do
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
Cspence is offline   Reply With Quote
Old 03-30-2010, 06:36 PM   #26
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

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.
hustler is offline   Reply With Quote
Old 03-30-2010, 06:37 PM   #27
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Quote:
Originally Posted by Cspence View Post
hmmmm....this this calculator wacked?


No, 130kpa IS 18psi....absolute
Jeff_Ciesielski is offline   Reply With Quote
Old 03-30-2010, 06:39 PM   #28
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by ScottFW View Post
It's superfluous because of the interpolation done by MS.
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.
hustler is offline   Reply With Quote
Old 03-30-2010, 06:47 PM   #29
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by Jeff_Ciesielski View Post
No, 130kpa IS 18psi....absolute
Damn, my ignition table could definitly use some work then.....right now only 25% of the table is defining parameters while in boost. This has changed the whole way I interpret this table . Thank you for the clarification sir
Cspence is offline   Reply With Quote
Old 03-30-2010, 06:56 PM   #30
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Quote:
Originally Posted by Cspence View Post
Damn, my ignition table could definitly use some work then.....right now only 25% of the table is defining parameters while in boost. This has changed the whole way I interpret this table . Thank you for the clarification sir
So wait, how much boost are you actually running relative to atmospheric pressure?
Jeff_Ciesielski is offline   Reply With Quote
Old 03-30-2010, 06:58 PM   #31
meatbag
iTrader: (50)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 7,357
Total Cats: 26
Default

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.
Attached Thumbnails
Anyone wanna give my fuel and spark tables a look over?-afrtargetresolution.jpg  
gospeed81 is offline   Reply With Quote
Old 03-30-2010, 07:28 PM   #32
Senior Member
iTrader: (3)
 
Join Date: Jul 2005
Location: Connect-I-Cut
Posts: 1,431
Total Cats: 0
Default

Please tell me this whole time you've been running only 130kpa (4psi??) lol
miataspeed2005 is offline   Reply With Quote
Old 03-30-2010, 07:28 PM   #33
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by Jeff_Ciesielski View Post
So wait, how much boost are you actually running relative to atmospheric pressure?
I'm runnin 18psi, so 225kpa'ish

Quote:
Originally Posted by gospeed81 View Post
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.
So much to take into account for . 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:
Cspence is offline   Reply With Quote
Old 03-30-2010, 07:30 PM   #34
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by miataspeed2005 View Post
Please tell me this whole time you've been running only 130kpa (4psi??) lol
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...
Cspence is offline   Reply With Quote
Old 03-30-2010, 07:46 PM   #35
Senior Member
iTrader: (3)
 
Join Date: Jul 2005
Location: Connect-I-Cut
Posts: 1,431
Total Cats: 0
Default

SO your spark up at 18psi is probably around 8* if MS was averaging out of your map
miataspeed2005 is offline   Reply With Quote
Old 03-30-2010, 08:24 PM   #36
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by miataspeed2005 View Post
SO your spark up at 18psi is probably around 8* if MS was averaging out of your map
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
Cspence is offline   Reply With Quote
Old 03-30-2010, 09:35 PM   #37
Senior Member
iTrader: (3)
 
Join Date: Jul 2005
Location: Connect-I-Cut
Posts: 1,431
Total Cats: 0
Default

^^^ yeah we need to tune your car... Dyno should be in 2-3 weeks but in the mean while I could help you tune it maybe Saturday
miataspeed2005 is offline   Reply With Quote
Old 03-30-2010, 09:48 PM   #38
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by miataspeed2005 View Post
^^^ yeah we need to tune your car... Dyno should be in 2-3 weeks but in the mean while I could help you tune it maybe Saturday
Damn.....I'd love to take you up on your offer but I got a few things going on this weekend. Please tell me your thinkin like May 1st for the dyno, cuz April is crazy for me between a few B-days, Easter, Uconn show, my buddys stag, my vacation/engagement ....May 1st will probably be the first weekend with things back to normal
Cspence is offline   Reply With Quote
Old 03-30-2010, 10:01 PM   #39
Senior Member
iTrader: (3)
 
Join Date: Jul 2005
Location: Connect-I-Cut
Posts: 1,431
Total Cats: 0
Default

Like the 24th or 25th but I gotta talk to the dyno guy first and see when the dyno is avaliable
miataspeed2005 is offline   Reply With Quote
Old 03-30-2010, 10:13 PM   #40
Elite Member
Thread Starter
iTrader: (11)
 
Join Date: Jun 2007
Location: Meriden, CT
Posts: 2,072
Total Cats: 1
Default

Quote:
Originally Posted by miataspeed2005 View Post
Like the 24th or 25th but I gotta talk to the dyno guy first and see when the dyno is avaliable
Damn you, I'm going to be in Niagara Falls the 23rd thru the 26th....maybe I'll get lucky and it'll be booked till May
Cspence is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
01-05 Fab9 PNP COPs (used) FrankB Miata parts for sale/trade 6 09-30-2015 12:48 PM
"Chimney Ethanol" E100 MiataGarage Engine Performance 5 09-30-2015 12:04 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 02:21 PM.