MEGAsquirt A place to collectively sort out this megasquirt gizmo

First Experience with Det, bad gas or bad spark

Thread Tools
 
Search this Thread
 
Old 05-01-2011, 12:43 PM
  #1  
Junior Member
Thread Starter
 
D.dutton9512's Avatar
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 166
Total Cats: 0
Default First Experience with Det, bad gas or bad spark

Yesterday I had my first real experience with detonation. Ambient temp was around 85 and I had just filled up the day before so this was the first time I ran the car in 75+ weather on this gas. At first I didn't even hear it but the knocksense flashed twice. I boosted to about 6lbs a second time and definitely heard it.

I'm running the following spark map except that I've reduced spark in anything over 100kpa by 2 degrees:



When I got home I reduced everything in 100+ kpa by another 3 degrees and went for a spin; everything seemed fine (although by that point ambient had dropped another 10 degrees).

The reason I think that it's just a bad tank of gas is that I've been running this map for a while and we've certainly had hotter days than yesterday down here. Not to mention the relative humidity was quite low yesterday. Last week I was boosting with no problems at 90 degrees ambient and 75% humidity.

Is this something that happens often? Should I tune for lower octane just in case?

Edit: I pulled my plugs today and no signs of det, in fact they look exactly the same as they did back in February (I took pictures). Though I know that doesn't mean anything concrete it's certainly not what I expected.

Last edited by D.dutton9512; 05-01-2011 at 01:36 PM.
D.dutton9512 is offline  
Old 05-01-2011, 02:50 PM
  #2  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
Default

(zack morris's phone)

That map has too much advance out of boost. In boost is similar to what I run.

Last edited by Braineack; 05-01-2011 at 02:50 PM.
Braineack is offline  
Old 05-01-2011, 03:26 PM
  #3  
Junior Member
Thread Starter
 
D.dutton9512's Avatar
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 166
Total Cats: 0
Default

My intercooler isn't the world's most efficient so I backed it off in boost and I ran the base DIY settings in the upper right (>5200rpm, 101kpa) as an added bit of protection. With the knocksense tuned to 5K this should be ok.

I'm certain I'm leaving power on the table now but it's worth it if I don't see white smoke on a hot day. At some point the "little bit more" mentality needs to be ignored.
D.dutton9512 is offline  
Old 05-02-2011, 08:11 PM
  #4  
Newb
 
catlin987987's Avatar
 
Join Date: Apr 2011
Posts: 32
Total Cats: 0
Default

What octane was it?
catlin987987 is offline  
Old 05-03-2011, 09:19 PM
  #5  
Junior Member
Thread Starter
 
D.dutton9512's Avatar
 
Join Date: Jan 2010
Location: Atlanta GA
Posts: 166
Total Cats: 0
Default

Sorry for the delay in response. It was 93 octane. I really feel like I lost a bit out of boost (in boost as well). So I'm going to add a degree or two in a few areas around 84kpa when we have another hot day to see if I can get it back.

I considered running a knock light unit but since it won't connect the to the MS and I have the detcans for tuning it would probably be a bit of overkill.
D.dutton9512 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
nbdooey
Miata parts for sale/trade
9
08-30-2017 09:50 PM
The Gleas
MEGAsquirt
3
10-01-2015 09:30 AM
lsc224
Miata parts for sale/trade
2
10-01-2015 09:17 AM
shooterschmidty
Engine Performance
8
09-30-2015 10:28 PM
Greasyman
General Miata Chat
2
09-28-2015 10:44 AM



Quick Reply: First Experience with Det, bad gas or bad spark



All times are GMT -4. The time now is 01:27 AM.