Pulley change, what to expect? - Vintage Mustang Forums
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post #1 of 8 (permalink) Old 08-01-2019, 07:58 PM Thread Starter
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Pulley change, what to expect?

Ok, been bumping into power steering problems for several autocross events, typically happens coming off a long high speed straight and hard brake into a very tight low speed turn. I've got several vids showing my steering locking up mid way through the turn. Called several power steering shops and of course they all wanted to sell me a new pump set up, UNTIL I spoke with the specialist at Turnone. Find out I've been over driving my PS, running a 7" crank pulley and 6" wp and ps pulley, at 6.5k rpm I'm turning way over the limit for both. It's very satisfying to hear from an expert who isn't in to it for the sale, THANKYOU Turnone! Took their advice and dropped to a 5.5" crank pulley (Marchperf) and just finished bolting everything back together, and burping the borgeson ps pump with a 1100psi control valve set up.

Don't know what to expect with the smaller crank pulley, or things to keep an eye out for. Any input would help. Next race isn't for another week.
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post #2 of 8 (permalink) Old 08-01-2019, 08:47 PM
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Have you talked to Dan from Chockostang about your issue? He has a tone of knowledge and in my experience is not trying to sell you things which are not needed. I worked with him during my PS rebuild and he was very helpful. Turned out great!
I would give him a call.



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post #3 of 8 (permalink) Old 08-02-2019, 01:54 PM Thread Starter
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I would agree with you if this was a stock scenario, but this is race situation running high rpms and low speed tight turns multiple times in 1 min timeframe. I've made the pulley change, which slowed down water and ps. So far, started up, temps look incredible, and alternator is at 14-15vdc at idle without changing the alt pulley. Have no noticable impact to the msd. Typically this undrive pulley change is done to get that extra 10hp, but I've done it to slow down my wp and ps; instead of 8k, it'll be about 5500rpm at redline. In theory, it should work, I want to hear from the ones that have done it.
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post #4 of 8 (permalink) Old 08-02-2019, 07:41 PM
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I'm running the factory PS setup rebuilt by Chockostang. I'm running the "Shelby" quick idler and steering arms with a larger 6" 86 F150 pulley to slow the pump down. A little notchy during parking lot maneuvers sometimes but no issues at the track other than some noted pukage of type F on the drivers side shock tower after an event. A smallish trans cooler is in the works for the return line.

Assuming your running a Borgeson box with a Chebby canned ham pump our systems have nothing in common other than some notchyness is more acceptable at parking lot speeds than system overload at 6500rpm. Curious how the Borgeson box works for autocross as Opentracker swears by it while others seem to swear at it?

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post #5 of 8 (permalink) Old 08-03-2019, 11:22 PM Thread Starter
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On the longer courses, 1 min or so the turns are not as tight so borgeson/saginaw ham can responds extremely well, especially in the slalom. But when you get to the smaller 30-40 sec tight courses, with extremely tight low speed turns, the pump doesn't like coming off a high speed scenario and then suddenly dropping to near idle rpm and turning full left or right. I made some control valve changes early in the year that worked very well in the long courses, but was obviously cooking the pump at 6500. I'm thinking Turnone had some very good feedback and "slowing the pump down" to stop the cavitation. With that I also changed the control valve back to stock, and did the pulley change..... fingers crossed.
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post #6 of 8 (permalink) Old 08-03-2019, 11:34 PM
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You could always go manual steer like I have for Autox
And about those videos, care to share with the class


Brad
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post #7 of 8 (permalink) Old 08-13-2019, 12:04 PM Thread Starter
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Sorry about the video's, couldn't get em loaded. Been busy, got the the pulley changed, and (forgot I) had a second pump under my bench. Test drove with questionable pump and new pulley clearly showed the pump was the problem. It was still locking at low speed. Replaced the pump and all feels great, no low speed issues. Took it for a nice drive, and as appears to be ready for the upcoming autocross weekend. Also, my temps do appear to be lower, and recover faster from any heat buildup from hard driving. It was easily 90+ outside so pretty surprised it didn't get overly hot. All looks good. In the midst of all this I was also doing a gear change from 3:55 to 3:80, but that's a whole-nother story.
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post #8 of 8 (permalink) Old 08-17-2019, 11:50 PM Thread Starter
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Finally got the vids uploaded.. you can see the camera shaking as the pump locks up in the turns (
) Over the last couple weeks I replaced the pump and reduced the crank pulley from 7" to 5.5". Was very surprised today, it was 95 degrees out and the car never got overly hot. This is a much longer course today and the power steering was perfect. Also did a gear change last week from 3:55 to 3:80 and the car felt incredibly good, stayed in the power band and helped exiting the turns, and the pump worked flawlessly. Ya know, it feels really good when you finally get it right. (
)
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