Lowest Idle on HKS 272/272 camshafts??

[bazeng]

Hi guys!

I'm just wondering what the lower rpm you guys can achieve with HKS 272/272 camshafts...

I'm having issues getting the AMG below 1200rpm without any form of idle control.
I'm hoping for about 800 rpm with idle control (to keep it from stalling).

Maybe I should play with cam gears etc to get it to idle a bit better.

Let me know fellas!
Thanks!

p.s please list your ecu + inj size also.

I'm running a motec m4 with 1000cc inj also.
With the SM4 i could get it to idle @ 900rpm w/o idle control and with 1000cc inj,

 

[D3bb4]

pretty sure mine is about 1k idle, maybe a little under, with 760cc injectors and vipec v44

 

[Lister]

950-1k for idle

 

[BMGTZ]

about 900 on the bc 272....if that helps as I have "heard" they are copies of hks.

lobe centres were opened up a bit by advancing the inlet.

 

[milkandoj]

My bc 272's seem to like it around 900-950.
Does the motec use the idle switch to let it know its idling? The one on the throttle body. Mine stopped working and the idle was all over the place. Fixed it and its much better. This is running ecmlink though, and sard 800's.

What 1000cc injectors have you got? Are they meant to be controllable at lower pulse widths? When doing my dead times i found some values on the net, and it idled like a pig so I had a play around and got then running fine, are the dead times correct?

 

[DIESTI]

Mine idles at 1100-1200.. thats the lowest i can get it..

that 272's on Microtech ECU i could get it lower if i had a idle control but i dont have one..

 

[DOUGMO]

mine was about 1000 with no idle control

 

[EVO-00X]

Baz if you can get them around the 1k mark that's probably the lowest I'd go. Not only are you still trying to keep the revs up when all the electrics are on like fans and high beams etc, you still want to have enough vacuum for the brakes to work when you are off throttle. A higher rpm will also aide against lobing the car along when you're doing slow speeds and also help if you have a lightened flywheel and grabby clutch so you dont stall it as easily.
With my Crower 280's Im idling around 1100-1200rpm on a street tune, cams havent been dialed in yet, but Im experiencing nice torque down low but have to keep the revs up otherwise the cams lobe me along at slow speeds off throttle.
Im also using Haltech ECU with the Haltech idle control and 880cc injectors.

 

[bazeng]

My bc 272's seem to like it around 900-950.
Does the motec use the idle switch to let it know its idling? The one on the throttle body. Mine stopped working and the idle was all over the place. Fixed it and its much better. This is running ecmlink though, and sard 800's.

What 1000cc injectors have you got? Are they meant to be controllable at lower pulse widths? When doing my dead times i found some values on the net, and it idled like a pig so I had a play around and got then running fine, are the dead times correct?

I got it to 1100rpm today with timing dropped to about 10 deg btdc. I'll try and drop it to 8 and see how she likes it.
It idles at about .95 lambda but stalls with any p/s movement or aircon.

Now I've wired up the stock ecu to
- idle switch
- stepper motor
- water temp sensor
- cas triggers
- air con switch
- ps switch
- air con relay
- dc +ve and gnd
- sensor gnd
- timing disable gnd pin

My goal is to use the stock ecu to fully control the stepper motor but so far it is not working =(

The stepper motor does pulse when turning the car on / off but apart from that, that is all it does.....
I'm going to try another stepper motor and see how it goes...

I'm thinking I may need a chip written for the stock ecu to target idle @ approx 1100rpm and it might work.
Maybe the stock ecu I have is dodgy?

Anyway, some troubleshooting is required.


Thanks for the input guys, 900 - 1100rpm sounds about right.

 

[milkandoj]

I got it to 1100rpm today with timing dropped to about 10 deg btdc. I'll try and drop it to 8 and see how she likes it.
It idles at about .95 lambda but stalls with any p/s movement or aircon.

Now I've wired up the stock ecu to
- idle switch
- stepper motor
- water temp sensor
- cas triggers
- air con switch
- ps switch
- air con relay
- dc +ve and gnd
- sensor gnd
- timing disable gnd pin

My goal is to use the stock ecu to fully control the stepper motor but so far it is not working =(

The stepper motor does pulse when turning the car on / off but apart from that, that is all it does.....
I'm going to try another stepper motor and see how it goes...

I'm thinking I may need a chip written for the stock ecu to target idle @ approx 1100rpm and it might work.
Maybe the stock ecu I have is dodgy?

Anyway, some troubleshooting is required.


Thanks for the input guys, 900 - 1100rpm sounds about right.

With it dying when you put aircon on, isn't there a compensation you can play with for that so it adjusts accordingly. And also able to log the PS pump working.
Ask to4garret about his idle control, his runs sweet with a ford idle control valve on bc280's.

Sound like the ecmlink does an ok job compared to these 1000's $$ computers, basically because it uses all the stock sensors.

 

[bazeng]

With it dying when you put aircon on, isn't there a compensation you can play with for that so it adjusts accordingly. And also able to log the PS pump working.
Ask to4garret about his idle control, his runs sweet with a ford idle control valve on bc280's.

Sound like the ecmlink does an ok job compared to these 1000's $ computers, basically because it uses all the stock sensors.

The Motec M4 is an old ecu which is limited to its outputs (only 4, 2 used for ignition, 1 for ce light and 1 for boost).

The mitsu stepper requires 4 outputs to be used, which would be ok if I had an Autronic SM4 or Motec M400 but no the M4.
The M4 is simply a boost / ign and fuel computer with the capability to log.

I did consider the ECM link but I don't want to run an AFM. Although it would be good to have knock control etc etc.

I'll keep going with this and see how I go but if all fails, I might convert to ECM link.

Carrying on, does anybody know if the GALANT GSR and the GALANT VR4 have the same ecu pins?

The aircon is triggering the ecu and the ecu is activating the aircon relay which should also bump up idle at the same time but it isn't.
Also the ps switch is working as I can see 12v when not active and 0v when working so the ecu knows that the ps is being used but idle isn't being bumped up either.

I'm thinking the stepper is faulty or the ecu is missing a critical input. I wonder if the stock ecu needs an AFM reading to start idle control....... how can I emulate a hz reading to the ecu??

 

[milkandoj]

You can run speed dencity on ecmlink. So no afm.
Ill shut up now coz i love it too much lol.

 

[rob323]

Baz, most factory ecu's raise the idle and then turn on the air con. They are proactive rather than reactive.
Megasquirt computers on MX5's have the same idle control problem because they can't react quick enough once the air con switches on.
I suspect this is the same problem you are having with the old Motec.