Landracing Forum
Tech Information => Technical Discussion => Topic started by: SALTRACER on December 13, 2008, 12:23:45 PM
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I am looking for a list of horsepower loss seen from various rearend types. (9" QC 12 bolt and so forth.)If I remember correct It was real results seen on a dyno. I thought it may have been on this site. I have done a search on this site and other boards, but I am unable to find the sheet that I remember. If anyone has this list could they post it or pm it to me. thanks Randy
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Randy
I remember that post and couldn't find it either (oldtimers disease). IIRC a 12 bolt was best due to pinion angle, followed by a 9" that used 4 HP more than the 12 bolt. Then the quick change used 10 HP more than the 12 bolt. Only the three rears were tested. YMMV
Ron Gibson, Omaha NE
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Sparky was the one with the research IIRC. May have been John Beckett.
DW
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Put in a 57-64 Pontiac..........Best #'s for a stong piece with the right pinion angle...
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As I recall "maguromic" screen name posted some accurate figures on rearends. I just tried to look up what he said, but for some reason was denied access to his past posts. Hope this helps.
Tom G.
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Had a similar post last January - a few numbers, but some decent general thoughts on the topic.
http://www.landracing.com/forum/index.php/topic,3424.0.html
Sparky's input - "Rule of thumb---the closer the pinion shaft is to the center line of the ring gear -- the less drag it will have".
That made sense to me, less side loading, less of a helical cut, less parasitic loss.
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Thanks for all of the replies. I have dug through the archives on the email list and found #s similar to what Ron posted. Thanks for looking guys, but if anyone finds the spreadsheet in question please post it. thanks Randy
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As I recall "maguromic" screen name posted some accurate figures on rearends. I just tried to look up what he said, but for some reason was denied access to his past posts. Hope this helps.
It looks like Jon has implemented some kind of privacy filtering. You can't look up anyone's profile anymore or see all of their past postings. As you have indicated that was a very useful feature. I hope the Ratliff fiasco was not the reason for the loss in functionality. Looking up someone's postings was as good as having an archive feature. It was a fast way to get information. :-(
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Guys remember---its precentage--loss gose up with power---greatest ratio selection is GM 7.5" fords new 8.8 is basacially the old GM 10-12---Rear axel selection the gift that keeps on giving---Merry Christmas :cheers:
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Guys remember---its precentage--loss gose up with power---greatest ratio selection is GM 7.5" (snip . . . )
True, if you are talking about "stock" gear ratios (i.e. OEM gears). However, the 9" Ford has so many "special" aftermarket ratios it surely has the widest selection of any. From NASCAR to circle track, Ford 9" ratios go from stock 2.47 to the 7:xx used in circle track. The last time I looked at a Richmond gear catalog it has 3x the Ford gears than any other brand. If you watch eBay, weird NASCAR ratios appear frequently. A NASCAR ratio would be a special gear cut just for a certain track and motor combination. The cost of cutting a special ratio is trival to a NASCAR team. Also, most of them show up REM conditioned.
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I was going to ask this in a new thread but I think it is a better fit here. If this is "thread jacking or drifting" please let me know. I apologize and will start a new subject.
I see a lot of gears REM conditioned. Does anybody have any data on just how much friction it eliminates? Or any increase in efficiency? Is there a shop on the West coast that does it?
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Here is some good info:
http://www.taylor-race.com/isotropic.cfm
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Thanks, Josh. Good explanation of the REM process. :-) However, like all others, it is difficult to nail down the increased efficiency (if any) it brings. They have some good information in their tech papers although they seem to be primarily focused on formula type road racing.
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Try this link for REM polishing http://www.remchem.com/
They have a few papers published. One of the PDF's on their site made a claim of a drop in temp of up to 50 degrees in an automotive application.
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Looks like www.mikronite.com is a similar process. All top level pro drag teams use this process to improve the fatigue/fracture life of ring and pinions. I have used it on my straight cut motorcycle transmission gears to decrease friction. Looks cool, the gears have a chrome appearance when returned. Like ceramic bearings I have no idea how much it helps but if one does enough of these things I am sure it has some benefit. All others just turn up the boost. :-D
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Thanks folks. :-) I'll research both proccesses and look for a west coast source.
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Larry, I would be careful about some racers claim. Several years ago the cars of Warren a Kurt Johnson carried sponsorship decals for a Cryogenic company. Turns out that Warren tried using it on his Lathe tooling for bucks on his race car
I am not saying that Cryo (for instance) doesn't work, nor any other process, but I wonder how much a coating or the REM process can help in 60-90 weight rear end lube.
p.s. unless you are banging gears, I think you could run virtually any domestic rear end you want. It's the big torque motors that need tough gears on the salt...............
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Some quick metallurgist answers:
Cold treating is done to reduce the amount of retained austenite in the quenched parts. Retained austenite is bad for dimensional stability and ductility. Under stress it transforms to untempered martensite, which is very hard and brittle. All quenched parts are tempered to give higher ductility. Strength does go down with tempering, but without it the parts would be too brittle, like a file.
REM surface treatment is really just improving the surface finish by removing the peaks. Reducing friction so you have the lubrication film between metal parts and not metal peak to metal peak contact. A set of old worn in gears has basically the same effect, the contact surfaces are polished down. The REM (or whatever name you want to call it) is just providing a head start on this.
My opinion is that these both do provide benefit, but more for reliability than for ultimate hp savings. That's my two Lincoln's worth.
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John,
I tested both at 2.47, from the quick change to the Ford 9” we gained about 6 HP. It was interesting when we went to the 12 bolt drop in and it jumped to 10 HP. My car is HP limited and runs on gas, so the only way is to gain the lost HP. Remember 75% of the horsepower loss occurs in the drive train.
I found the post I was looking for. I thought this was useful information.
Tom G.