stepper motor - alternatives

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Seight-V8
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stepper motor - alternatives

Post by Seight-V8 » Sun Sep 08, 2019 6:10 pm

hello all,

If I wanted better idle control on my Rover v8 GEMS 4.6 engine, I presume I would do away with the stepper motor in the throttle housing.

But what valve would be in its place and how would it be plumbed?

I'm running a gems 4.6 with a modified throttle plate to act westfield plenum, and a VEMS ecu.

cheers
scott



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Re: stepper motor - alternatives

Post by ChrisJC » Sun Sep 08, 2019 6:31 pm

You are going to have to explain your thinking a bit more. The stepper motor is controlled by the ECU to maintain idle speed. So if you do away with it, there will be no idle speed control at all!

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Re: stepper motor - alternatives

Post by Seight-V8 » Sun Sep 08, 2019 7:18 pm

sorry, just wondered if there's anything better the stepper motor I currently have.

I see the thor engine has a bosch 2 wire valve, would this be any better, or am I just going up the garden path so to speak.

just a train of thought I currently have.

thanks
scott

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Re: stepper motor - alternatives

Post by DaveEFI » Mon Sep 09, 2019 9:05 am

I have a Bosch PWM valve fitted where stepper motor unit goes. With MegaSquirt, I had to add a suitable high current driver
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Re: stepper motor - alternatives

Post by ChrisJC » Mon Sep 09, 2019 5:27 pm

I would say that if the stepper works properly, there's nothing to be gained by changing it.

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Re: stepper motor - alternatives

Post by stevieturbo » Mon Sep 09, 2019 5:35 pm

a lot will be down to what your VEMS is happy with using.

A stepper motor would usually be pretty good.

Simple 2 wire valve...simple.

DBW....most versatile.

I would be trying to get a good stable hot idle first, before letting any type of idle control doing anything though, so as to need it to do very little work at all.
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Re: stepper motor - alternatives

Post by DaveEFI » Mon Sep 09, 2019 6:43 pm

ChrisJC wrote:
Mon Sep 09, 2019 5:27 pm
I would say that if the stepper works properly, there's nothing to be gained by changing it.

Chris.
The hotwire type don't have a good reputation for reliability, I was told. Hence my going for the Bosch. MegaSquirt has a built in stepper motor driver, so that choice was more work. It also seems to be the standard on modern vehicles.
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Re: stepper motor - alternatives

Post by Coops » Tue Sep 10, 2019 6:41 pm

we ditched the stepper 2yrs ago, and set idle with the butterfly stop for now,
currently have no fast idle control either until Ive finished doing my 2 wire extra air valve set up.
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Re: stepper motor - alternatives

Post by stevieturbo » Tue Sep 10, 2019 10:56 pm

In a lot of cars, simply using timing for idle control will be quite fine.
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Re: stepper motor - alternatives

Post by SimpleSimon » Wed Sep 11, 2019 8:47 pm

Bosch 2 or 3 wire get my vote older Volvo Saab BMW GM etc , if you run a big cam ign scatter spark dialing in lots of advance etc wont be enough for warm up so some kind of ICV is essential in some instances, I agree with Dave the Hotwire stepper is a pain in the arse and often erratic in its action Lucas and Megasquirt control
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Re: stepper motor - alternatives

Post by DaveEFI » Thu Sep 12, 2019 8:52 am

On my SD1 heat soak can be a real problem on a hot re-start. The PWM ICV is set to open further during a hot start, and return to the correct idle speed in a controlled way. Of course you can do this manually using the throttle pedal.
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