Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: August 15, 2016 12:21PM

On the MGB, clearly the gearbox does not clear the forward part of the steering column bracket in the car and part of that bracket has to be removed along with the nut for the forward most bolt. Do we have any guidelines on how much of the bracket to remove and any recommendations on how to do that? (up under the dash and hard to get to)

Is it reasonable to try to save the odometer reset knob bracket?

Jim


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: August 19, 2016 12:51PM

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Jim


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: August 19, 2016 12:55PM

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Jim


DiDueColpi
Fred Key
West coast - Canada
(1198 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

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Re: EPS: How much to cut/best method?
Posted by: DiDueColpi
Date: September 19, 2016 03:56AM

A little late to the party(sorry Jim), the GM EPS units can be shortened substantially.
The output shaft can not be modified which is ok as it's very short already.
The input shaft however can be shortened up substantially.
I have cut the input shaft right up to the end of the splines, approx 4 1/2" with out any ill effects.
Remote mounting the control module lets you flip the unit upside down giving you all the foot clearance that you could ever need.
Make sure that the control module has a decent heat sink bolted to it or it will burn up.

Cheers
Fred


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: September 19, 2016 10:36AM

I've been running the Bruno pot set as low as it will go without becoming erratic, which it will do if turned down too far. So far no complaints. I think a fixed resistor could be substituted for the pot, and would be a good idea.

Heat sink is probably a good idea also, might have to look at that.

Jim


pcmenten
Paul Menten

(235 posts)

Registered:
10/08/2009 10:40AM

Main British Car:


Re: EPS: How much to cut/best method?
Posted by: pcmenten
Date: September 19, 2016 05:12PM

Hi Jim,

I'm sure you've already thought of this but you might consider measuring the resistance about where you have the pot adjusted, then splice in a resistor in series that's slightly less than that resistance. This will give the pot better granularity of adjustment near your preferred setting. Example; if the pot measures 3k ohms at the sweet spot, splice in a 2.7k ohm resistor from ground to the pot.

But I'm a little concerned why it becomes erratic. That doesn't sound quite right.

Paul


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: September 20, 2016 11:25AM

Paul, I think it is the nature of the type of pot that was used, more than anything else, unless the resistance just gets too high or low at the end. Most inexpensive pots don't have much in the way of end stops, and often the wiper will go past the end of the resistive area over to the contact area. I suspect this is what is happening here. It probably goes wonky because continuity is interrupted.

In the OEM application they might have used a switch instead, for cruise or sport mode, or they might have sent a signal from the PCM based on vehicle speed. But I don't feel either is necessary here. We could use the slide switch in the cowling to switch in a different resistor for driving and parking for instance, but I don't feel that would be helpful. Sitting still the assist is just fine, does not need any more boost, and at cruise, we we are already at the end of the adjustment so it may not be possible to decrease the assist any further. And I'm not so sure we would want to anyway.

Jim



DiDueColpi
Fred Key
West coast - Canada
(1198 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: EPS: How much to cut/best method?
Posted by: DiDueColpi
Date: September 22, 2016 09:22PM

Hey Jim, I was mucking around with one of the EPS installs today and thought that I would haul out my scope to see what the Bruno setup is putting out.
Of the two outputs to the EPS module, the pink lead is the +12v to turn the unit on.
The purple lead is a pulse width output.
It's a pretty messy signal and that may explain your problem at the lower setting. It's raggedy enough that I couldn't nail down a reading on the actual duration. It is possible that it's a serial signal but I don't think that the Bruno controller is that sophisticated.
Interestingly with the unit powered up on the pink wire only, you get what feels like 50% assist.
Must be a fail-safe base setting and the pulse width skews it up or down from there.
You could probably use an output from your trans controller that would be speed based to replace the Bruno unit.

Cheers
Fred


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5241 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: EPS: How much to cut/best method?
Posted by: BlownMGB-V8
Date: September 24, 2016 11:48AM

Wow, Fred that's really cool. I've been playing with the setting after putting the swaybar on the car and using the entire range minus a little on the ends. 50% would not be a problem, in fact I sort of like it around there. Food for thought anyway.

Jim


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