Discussion
I doubt your loping idle has anything to do with the cam profile.
My Chim suffered a slightly hunting idle when I bought it.
As a first step I went through the car replacing the injectors & everything on the ignition side.
I then fitted a V8D Stealth cam, removed the pre-cats, installed a Tornado chip & had a rolling road session with Mark Adams.
Some good improvements to performance & throttle response were made but none of it solved the hunting, I discussed the idle with Mark Adams but a clear answer was not forthcoming.
It seemed to me like something was causing poor combustion at idle, perhaps an exhaust restriction or a weak spark?
Perhaps both
With the removal of the pre-cats giving little or no improvement I decided to replace the original big cat Y Piece with a second hand ACT de-catted one that luckily came my way.
Immediately I fitted the ACT Y piece the idle was transformed.
Finally I moved away from the standard BP7ECS plugs (which on inspection always seemed to show early signs of fouling) and replaced them with a set of BPR6EIX Iridium.
The combination of the ACT de-cat flowed Y piece & the hotter iridium plugs made a massive difference to the way my Chim idles.
It now idles so smoothly is like a different car to the one I bought it three years ago.
The only Chimaera I have heard that idles better is Bassfiend's (Phil's) Canems ECU equipped car with waisted spark and a Bosch idle valve replacing the Lucas stepper motor.
One day that old Dizzy & 14CUX ECU of mine will go to a new home
But for now I think I've got it just about as good as it's ever going to get, and it's really pretty good for what it is
Improve your spark, lose the big cat, and I bet your loping idle will be a thing of the past.
My Chim suffered a slightly hunting idle when I bought it.
As a first step I went through the car replacing the injectors & everything on the ignition side.
I then fitted a V8D Stealth cam, removed the pre-cats, installed a Tornado chip & had a rolling road session with Mark Adams.
Some good improvements to performance & throttle response were made but none of it solved the hunting, I discussed the idle with Mark Adams but a clear answer was not forthcoming.
It seemed to me like something was causing poor combustion at idle, perhaps an exhaust restriction or a weak spark?
Perhaps both
With the removal of the pre-cats giving little or no improvement I decided to replace the original big cat Y Piece with a second hand ACT de-catted one that luckily came my way.
Immediately I fitted the ACT Y piece the idle was transformed.
Finally I moved away from the standard BP7ECS plugs (which on inspection always seemed to show early signs of fouling) and replaced them with a set of BPR6EIX Iridium.
The combination of the ACT de-cat flowed Y piece & the hotter iridium plugs made a massive difference to the way my Chim idles.
It now idles so smoothly is like a different car to the one I bought it three years ago.
The only Chimaera I have heard that idles better is Bassfiend's (Phil's) Canems ECU equipped car with waisted spark and a Bosch idle valve replacing the Lucas stepper motor.
One day that old Dizzy & 14CUX ECU of mine will go to a new home
But for now I think I've got it just about as good as it's ever going to get, and it's really pretty good for what it is
Improve your spark, lose the big cat, and I bet your loping idle will be a thing of the past.
Edited by ChimpanLucky on Friday 18th May 13:34
debaron said:
ChimpanLucky said:
I doubt your loping idle has anything to do with the cam profile.
I thought smooth idle had everything to do with cam profile?! - assuming all other things are working correctly (stepper, ecu etc)Edited by ChimpanLucky on Friday 18th May 13:34
What I am saying is on my car the cam had nothing to do with my hunting idle.
It did it with the Kent 435 TVR fitted to my 4.0HC from new, and it did it on the Stealth.
It wasn't until the restriction of main cat was removed and the fuel was being burnt more effectively that I improved the hunting.
The truth is I think the OP Alex has already ditched his cats and I know he has a lumpy cam.
But I still wouldn't mind betting when his MegaSquirt project gets the green light it will idle much better.
If nothing else (& there's lots else) these cars are crying out for a better spark.
Its defiantly a cam lope
hunting raises the revs up and down slower
Its a 300 duration cam in/ex with solid lifters if that doesn't make it lope, how much bigger do I need to go?
And yes it de-catted Dave (+25hp)
I don't think the idle with improve much with the megasquirt
But yeah as you say its screaming out for a proper spark! missfires and lumpy as hell when cold
Skiver- Its a new cam only done about 1000 miles if that
hunting raises the revs up and down slower
Its a 300 duration cam in/ex with solid lifters if that doesn't make it lope, how much bigger do I need to go?
And yes it de-catted Dave (+25hp)
I don't think the idle with improve much with the megasquirt
But yeah as you say its screaming out for a proper spark! missfires and lumpy as hell when cold
Skiver- Its a new cam only done about 1000 miles if that
ChimpanLucky said:
The only Chimaera I have heard that idles better is Bassfiend's (Phil's) Canems ECU equipped car with waisted spark and a Bosch idle valve replacing the Lucas stepper motor.
Awwww shucks thanks! 
Yup - idles much better and roars like a mad thing (had a couple of very appreciative lads in the Dartford tunnel this morning) ... however I'm even more tempted (now that it does idle so nicely) to look at a V8D H404 or P404 now.
Phil
Bassfiend said:
ChimpanLucky said:
The only Chimaera I have heard that idles better is Bassfiend's (Phil's) Canems ECU equipped car with waisted spark and a Bosch idle valve replacing the Lucas stepper motor.
Awwww shucks thanks! Yup - idles much better and roars like a mad thing (had a couple of very appreciative lads in the Dartford tunnel this morning) ... however I'm even more tempted (now that it does idle so nicely) to look at a V8D H404 or P404 now.
Phil
Bassfiend said:
however I'm even more tempted (now that it does idle so nicely) to look at a V8D H404 or P404 now.
Mines a V8D P248I've always been told to pick a cam I think I want then buy 2 stages lower, instead I bought 1 stages higher and have no regrets
BUT this may not be to every ones taste,
Cons - pain in the ass to start when cold
- lack of torque lower down
- bad mpg below 3k rpm
Pros - less wheel spins at lower rpm
- at 3.5-6.5krpm the devil himself is trying to escape the engine
- Cam lope
- surprisingly good mpg 3k+rpm
You can hear it screaming when revved and the tyres chirping going into 3rd,sorry for bad video I was testing my wideband gauge under full load
http://www.youtube.com/watch?v=UGYWFJWee8M
And still slower than mine ,forget the race cams and get your fueling right ..
I have nothing special under the bonnet but i have a real 340 hp before the new injectors and re tune
30mpg on a run ..
You need to get rid of the 14cux and then you can move on ..
What happened to the small block cast Ford engine ?
I have nothing special under the bonnet but i have a real 340 hp before the new injectors and re tune
30mpg on a run ..
You need to get rid of the 14cux and then you can move on ..
What happened to the small block cast Ford engine ?
SILICONEKID340HP said:
Bassfiend said:
ChimpanLucky said:
The only Chimaera I have heard that idles better is Bassfiend's (Phil's) Canems ECU equipped car with waisted spark and a Bosch idle valve replacing the Lucas stepper motor.
Awwww shucks thanks! Yup - idles much better and roars like a mad thing (had a couple of very appreciative lads in the Dartford tunnel this morning) ... however I'm even more tempted (now that it does idle so nicely) to look at a V8D H404 or P404 now.
Phil
Phil
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