Afr on idle with Greys?
Trending Topics
Norris Motorsport
Joined: May 2003
Posts: 3,437
Likes: 3
From: Derbyshire
12 - 12.5 :1 AFR at warm idle is usually the best AFR to give stable idle when using 403's.
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
12 - 12.5 :1 AFR at warm idle is usually the best AFR to give stable idle when using 403's.
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
A qualified answer
Too many posts.. I need a life!!
Joined: Jul 2003
Posts: 754
Likes: 0
From: South Wales - Never Forget Your Welsh!
Awsome..... I had the same question with mine which idles at around 13.5:1, which idles reasonably well.
Karl, need to book the car back in with you for a setup please.... you busy?!
Huw
Karl, need to book the car back in with you for a setup please.... you busy?!
Huw
Too many posts.. I need a life!!
Joined: Jul 2003
Posts: 754
Likes: 0
From: South Wales - Never Forget Your Welsh!
PassionFord Post Whore!!
Joined: Jun 2003
Posts: 5,472
Likes: 223
From: Marlow Bucks
PassionFord Post Whore!!
Joined: Jun 2003
Posts: 5,472
Likes: 223
From: Marlow Bucks
No, but they should run a cat.
I'm just putting one on mine so it's road legal again, removable for track days etc but it flies through a cat test
I'm just putting one on mine so it's road legal again, removable for track days etc but it flies through a cat test
Last edited by James @ M Developments.; Jan 2, 2014 at 05:53 PM.
PassionFord Post Whore!!
Joined: Jun 2003
Posts: 5,472
Likes: 223
From: Marlow Bucks
Norris Motorsport
Joined: May 2003
Posts: 3,437
Likes: 3
From: Derbyshire
Yes the weber IAW ecu's are old but a more modern ecu does'nt help with bosch 403's. They have a very shallow angle pencil spray pattern, which means the atomisation of the fuel is very poor.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
Which is a common known fact so im a bit puzzled to the fact how a modern ecu can change this as to my knowledge you would need to change the nozzle ect to get the above to happen not spend 2k plus on another ecu
Yes the weber IAW ecu's are old but a more modern ecu does'nt help with bosch 403's. They have a very shallow angle pencil spray pattern, which means the atomisation of the fuel is very poor.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
Agree totally Karl, mine on Greys is so lumpy on idle, can't wait to get it setup again with new injectors etc tbh.
Yes you'll need a map
Advanced PassionFord User
iTrader: (1)
Joined: Nov 2004
Posts: 1,735
Likes: 15
From: in me garage working on the cossie
PassionFord Post Whore!!
Joined: Jun 2003
Posts: 5,472
Likes: 223
From: Marlow Bucks
Thread
Thread Starter
Forum
Replies
Last Post
nicodinho
Ford Non RS / XR / ST parts for sale.
6
Oct 7, 2015 12:56 PM
