Running lean and detonation

OP
OP

Kong76

Well-Known Member
Joined
Apr 23, 2016
Threads
43
Messages
1,900
Reaction score
431
Location
Turlock, Ca
Vehicle(s)
2016 Ingot Silver GT
If your vacuum gauge is showing greater than 15" of Hg or more you have no vacuum leak. Most Coyote engines with stock cams run 17-19" Hg at an Idle of 750 after warmup. This is assuming that VCT is tuned correctly. If VCT strategy is creating overlap effect vacuum will be closer to static. For those reading who don't undcerstand VCT basics or cam basics...disregard.

Some vaccum leaks aren't apparent until throttle and load are involved.

 

Elp_jc

Well-Known Member
Joined
May 2, 2020
Threads
48
Messages
3,531
Reaction score
784
Location
USA
Vehicle(s)
None
My car idles like at 625, so vacuum must be lower. I'm surprised the engine doesn't vibrate at that low of an rpm without any load (like an auto). Amazing.
 

ugstang17

Well-Known Member
Joined
Oct 26, 2018
Threads
9
Messages
1,329
Reaction score
689
Location
unknown
Vehicle(s)
none
Some vaccum leaks aren't apparent until throttle and load are involved.
Vacuum DECREASES (moves closer to static pressure or 0 on the gauge) as throttle increases. Therefore vacuum related issues disapate as throttle position opens. But you are telling me that at partial throttle you can have a greater chance of a vacuum leak where vacuum is closer to ambient pressure than at idle where vacuum is at its greatest. The only time I have ever seen an issue at higher throttle is on a FI setup in which boost is escaping as pressure in the engine goes past static and into a positive pressure condition. Your chasing a crap tune.
 
OP
OP

Kong76

Well-Known Member
Joined
Apr 23, 2016
Threads
43
Messages
1,900
Reaction score
431
Location
Turlock, Ca
Vehicle(s)
2016 Ingot Silver GT
Vacuum DECREASES (moves closer to static pressure or 0 on the gauge) as throttle increases. Therefore vacuum related issues disapate as throttle position opens. But you are telling me that at partial throttle you can have a greater chance of a vacuum leak where vacuum is closer to ambient pressure than at idle where vacuum is at its greatest. The only time I have ever seen an issue at higher throttle is on a FI setup in which boost is escaping as pressure in the engine goes past static and into a positive pressure condition. Your chasing a crap tune.
I do see my vacuum drop to 0 on wot for a few seconds. Makes perfect sense now. I didn't get lean conditions until car was under load so that is why I leaned that direction.

Shit tune for sure. I was warned by Shawn.
 

Grimreaper

Well-Known Member
Joined
Jan 23, 2019
Threads
13
Messages
354
Reaction score
119
Location
Dallas
Vehicle(s)
2017 GT
did you ever log this to see that it was actually commanded lean? or reading lean besides the dash readout?

90% pedal is needed for full wot enrichment, otherwise 13.7 afr is typical of enrichment at tipin but still calling for 1 lambda.

the lack of octane is to blame not the tune. its just overly optimistic with the timing!
using the VID plug to pull timing (its the octane adjust in the procal software) only yanks timing up top above 0.80 load iirc. so up top its fine. but low rpm/med loads still gunning for mbt.
 


OP
OP

Kong76

Well-Known Member
Joined
Apr 23, 2016
Threads
43
Messages
1,900
Reaction score
431
Location
Turlock, Ca
Vehicle(s)
2016 Ingot Silver GT
did you ever log this to see that it was actually commanded lean? or reading lean besides the dash readout?

90% pedal is needed for full wot enrichment, otherwise 13.7 afr is typical of enrichment at tipin but still calling for 1 lambda.

the lack of octane is to blame not the tune. its just overly optimistic with the timing!
using the VID plug to pull timing (its the octane adjust in the procal software) only yanks timing up top above 0.80 load iirc. so up top its fine. but low rpm/med loads still gunning for mbt.
I don't have a way to log it, I was just going off my obd2 reader and its ltft and stft trends.

The pinging/ detonation is enough for me to call it a day. I can only imagine what this constant use of boostane is doing to the internals. Its not worth it to me to continue to run this tune this way. If it can't run on 91 like advertised then the kit has to go in my opinion.
 

ice445

Well-Known Member
Joined
Apr 13, 2020
Threads
24
Messages
4,310
Reaction score
4,585
Location
Salt Lake City, UT
First Name
Ryan
Vehicle(s)
2020 Mustang GT 6MT
A dirty or bad MAF that underreports can create this issue too. Just went through it on a different car
 

racingandfishing

Well-Known Member
Joined
Oct 27, 2015
Threads
6
Messages
711
Reaction score
448
Location
Austin, Texas
Vehicle(s)
2015 Mustang GT PP
There was a claim that 40% of people with this tune have detonation.

Would be interesting to see a poll of where people leave who experience these issues to see if there is a relation to the gasoline in that geographic.
 
OP
OP

Kong76

Well-Known Member
Joined
Apr 23, 2016
Threads
43
Messages
1,900
Reaction score
431
Location
Turlock, Ca
Vehicle(s)
2016 Ingot Silver GT
A dirty or bad MAF that underreports can create this issue too. Just went through it on a different car
Been that route as well.
There was a claim that 40% of people with this tune have detonation.

Would be interesting to see a poll of where people leave who experience these issues to see if there is a relation to the gasoline in that geographic.

Wouldn't doubt it. We have crappy over priced gas here in Ca.
 

 
Wheel Designers
Top