Engine detonation - what ignition advance is safe? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 05-09-2012, 04:20 PM   #1
Junior Member
Thread Starter
 
Join Date: Mar 2012
Location: Portugal
Posts: 199
Total Cats: -12
Default Engine detonation - what ignition advance is safe?

Hey all!

I'm almost done with tuning my VE table, and it's pretty nice as of right now. However, I'm not so sure about the timing. I'm using the timing maps that came with my MS, which I reckon are unchanged compared to the DIY 90-93 maps that diyautotune provides.

So here's the thing: I don't feel too safe with them. Even though I'm not turbo'd, I know the car keeps the ignition running from 10 to about 30 stock, but these maps put it running in the 16 to 37 area. That's an average 6 advance. I have since detuned the whole map by one degree. Here's my current map:



Now, the reason I'm still worried is that I'm keeping the car running on conditions that might be a bit too lean for this map. In a rough way, here are some of the AFRs that I'm getting:

on idle: 14.9
while cruising (low revs): 14.2-14.8
while cruising (mid revs): 15-15.5
while driving well...erm.... enthusiastically: 13.5 to 14.5

I'm a bit more worried about the fact that I've been crusing slightly lean, not being compatible with the fact that my ignition is still pretty advanced.

Oh, another thing is that I set my ignition to retard 1 for every 5C that the IAT goes above 35C. That should keep me a bit safer too.

And I'm running on 95 octane pump gas (should be the same as your 90-91 octane over there in the USA).

So, what do you guys think? I want to make sure I'm safe at least until I get a knock sensor thingy, or some det cans!
Attached Thumbnails
Engine detonation - what ignition advance is safe?-ignition.png  
ThunderFox is offline   Reply With Quote
Old 05-09-2012, 04:23 PM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

you can add about 5-6 everywhere in boost and be fine. everything else is fine.
Braineack is offline   Reply With Quote
Old 05-09-2012, 04:28 PM   #3
Senior Member
 
Join Date: Aug 2010
Location: Arl. Texas
Posts: 937
Total Cats: 23
Default

There is no boost goin on here.
Miater is offline   Reply With Quote
Old 05-09-2012, 04:28 PM   #4
Elite Member
iTrader: (10)
 
soviet's Avatar
 
Join Date: Jan 2010
Location: VA
Posts: 3,519
Total Cats: 260
Default

http://www.miataturbo.net/attachment...chmentid=20150

I don't know what thread this file is from but I found it very useful.
That ignition map is very safe but sacrifices a lot of power.
soviet is offline   Reply With Quote
Old 05-09-2012, 04:29 PM   #5
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,372
Total Cats: 1,333
Default

WOT AFRs should be 12.8-13.0 for a non-turbo car. Your 100kpa timing is pretty conservative as well - I would lift the 101kpa row by 3* across the board, and then blend it smoothly into the 55kpa row.

Boosted timing depends a lot on which turbo you have.
Savington is offline   Reply With Quote
Old 05-09-2012, 07:05 PM   #6
Junior Member
Thread Starter
 
Join Date: Mar 2012
Location: Portugal
Posts: 199
Total Cats: -12
Default

I'll sort out the boost timing later, when I get a turbo. Eventually I'll be pointing at a small turbo (GT20 maybe?) for a low pressure build, and all those lines will have to be redone for more precision eventually. What I'm more worried about now, is the cruising (particularly in the 84kPa mark, where the car seems to be most of the time when picking up speed) part of the map. Detonation really freaks me out lol.

I don't suppose there's a map somewhere from the stock ECU of the 1.6? I know I saw some 1.8 maps around, that someone stimmed off the stock ECU, but no such luck in finding a 1.6 map. Only the base advance times.
ThunderFox is offline   Reply With Quote
Old 05-09-2012, 07:14 PM   #7
Junior Member
Thread Starter
 
Join Date: Mar 2012
Location: Portugal
Posts: 199
Total Cats: -12
Default

Quote:
Originally Posted by soviet View Post
http://www.miataturbo.net/attachment...chmentid=20150

I don't know what thread this file is from but I found it very useful.
That ignition map is very safe but sacrifices a lot of power.
Gee, thanks a bunch for that file you posted! Even though I got most of my targets fine for what I want, it's really nice to know the useable limits! You're awesome
ThunderFox is offline   Reply With Quote
Old 05-11-2012, 10:18 PM   #8
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

if you plan to run lean you want more advanced timing.
15.5 under cruise really isn't close to what I would consider lean
I've run before 16.5 \ 17 under cruise wtih 38 degrees of timing on my car.
Also I run into the 30s around 2000rpm down low considering I cruise around town there.
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 59 12-15-2017 09:00 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Changing from 460cc to flow force 610cc in diypnp 90 Turbo MEGAsquirt 19 10-19-2015 04:23 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
01-05 Fab9 PNP COPs (used) FrankB Miata parts for sale/trade 6 09-30-2015 12:48 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 03:04 AM.