DIYPNP Spark advance basemap for boost - 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 05-04-2012, 10:58 AM   #1
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Nov 2010
Location: Long Island
Posts: 108
Total Cats: 9
Question DIYPNP Spark advance basemap for boost

I've tried searching extensively and have not been able to figure this out for whatever reason.

I have a DIYPNP that I've actually been running in my boosted 95 Miata for the last 250 miles during break-in. Currently have a rebuilt 1.8, BP-T cams, IHI RHF5 (MSM) turbo running at 7psi, COPS, and 460cc injectors. I set the trigger angle offset at 8.00 degrees to get it timed to 10 deg base.

I had prior experience in tuning with eCtune and Crome, both of which have a feature that automatically retards timing a specified amount per lb of boost. I'll admit that my math is f**kin horrible so my first basemap that I've been tuning with had 2.5 degrees pulled per 20KPA above 100KPA. Well, it's been running seemingly fine (I haven't heard any hints of detonation), but last night while diagnosing my idle issues I realized that this still might be too far advanced so another attempt was made to figure out the best safe starting point. Behold my new timing map attached with 1.25 deg timing pulled per PSI or 3.62 degrees per 20KPA (20KPA = 2.9PSI * 1.25 retard = 3.62 deg pulled per row).

Someone please tell me I'm an idiot - because this just doesn't look right. I've tried searching extensively for ignition tables for similar setups, but can't seem to find what I'm looking for.

EDIT: And then it dawned on me that there's no need to pull an additional 1.25 degrees per lb since it's already accounted for in the timing table......wow, that was a moment.

Just to be safe I took an extra 10% of timing from the boost section by multiplying by .9. That should work for now...will keep my detcan handy anyway.
Attached Thumbnails
DIYPNP Spark advance basemap for boost-sparktiming.jpg  

Last edited by JustinOMGWTF; 05-04-2012 at 06:28 PM.
JustinOMGWTF is offline   Reply With Quote
Old 05-04-2012, 11:03 AM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

that's awful.

youre retarding over 10 degrees just as you enter boost. those numbers are the final timing angle numbers.


should look more like this:

Braineack is offline   Reply With Quote
Old 05-04-2012, 04:42 PM   #3
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Nov 2010
Location: Long Island
Posts: 108
Total Cats: 9
Default

Appreciate the quick response - but that's what an end result looks like - correct? I have no problems tackling the VE table, but I'm not comfortable tuning the timing for optimal results...I'd prefer to leave that to the professionals.

What I'm seeking is a rough guideline as to what I should do to the timing table to allow me to continue working out the bugs with the rest of my setup without blowing up my engine in the meantime. It was a previous understanding that retarding the timing x amount per PSI of boost is a good starting point - so how is that applied here besides how I've done it? I've searched through all the megasquirt documentation already...perhaps someone can point me at where I need to read?

Thanks in advance...
JustinOMGWTF is offline   Reply With Quote
Old 05-04-2012, 04:47 PM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

copy the above i posted and continue on with life?
Braineack is offline   Reply With Quote
Old 05-04-2012, 04:57 PM   #5
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Nov 2010
Location: Long Island
Posts: 108
Total Cats: 9
Default

I'd feel safer with the base usdm-mazda-miata-9495-18bp-mt-batch-3.0.3.msq timing map - I think.

Attached Thumbnails
DIYPNP Spark advance basemap for boost-stockmiataign.jpg  
JustinOMGWTF is offline   Reply With Quote
Old 05-04-2012, 08:05 PM   #6
Junior Member
 
Join Date: Nov 2009
Location: Dumfries, VA
Posts: 109
Total Cats: 2
Default

If you're worried, take about 5 to 7deg off Brain's timing above 100kPa and start from there.

Last edited by sccaax; 05-04-2012 at 08:17 PM.
sccaax is offline   Reply With Quote
Old 05-04-2012, 11:50 PM   #7
Junior Member
 
Join Date: Mar 2010
Location: Durham, NC
Posts: 409
Total Cats: 19
Default

Would 10ATDC do anything other than melt exhaust bits?
FatKao is offline   Reply With Quote
Old 05-05-2012, 08:38 PM   #8
Junior Member
 
Join Date: Nov 2009
Location: Dumfries, VA
Posts: 109
Total Cats: 2
Default

Guy on the dyno told me that anything shallower than about 7deg before TDC and you run the risk of not sparking off a majority of the mix. The flame front isn't traveling fast enough even to keep up with the speed of the piston by the time the exhaust valve opens. So, the mix continues to burn in the exhaust overheating your turbo turbine housing, seals and wheel and frying/plugging your cat. This would also likely torch your exhaust valves, which is a surface area to thickness and volume thing. The car will run like a pooch in this situation and it would probably come on fairly rapidly. At some point, it would act just like hitting the rev limiter. So, you might not notice except when viewing a datalog of the event.
sccaax is offline   Reply With Quote
Old 05-05-2012, 10:36 PM   #9
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

would make sense I have the rev limiter pull timing out, and there is a noticeable drop in power output
Techsalvager 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 58 12-13-2017 10:04 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM


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 04:20 AM.