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  #1 (permalink)  
Old 05-14-2019, 07:29 AM
GjC GjC is offline
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Default Richmond OD

I have a CCX with the 4 speed Top Loader and I'm considering swapping out the tranny for a Tremec 5 speed (.82 OD) or the Richmond Super Street OD
(.77 OD), with either transmission is it possible to swap out 5th gear for higher ratio such as .91 for 5th gear? The rear end is a 2.88 and I have 26.5" diameter tires the car revs at 2450 at 60 MPH, I know that is probably a good RPM but I would like to drop it. The car has a 428 CJ and HP peaks at 5800 rpm's, if my calculations are correct with the rear end gears and tire diameter with a .91 OD the motor will be turning at 2000 rpm's at 60 MPH. Either tranny will give me good acceleration in 1st -4th gear it's the cruise ability on the highway I'm looking for (I do mostly highway driving), the .82 and .77 OD are to low with the 2.88 gears.
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Old 05-14-2019, 08:59 AM
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OK, I may not be the best person to be answering this, but I think you need to rethink this. The .82 and .77 are going to give you a lower RPM than a .91 5th gear at the same speed. The Richmond with the .77 being the lowest of the three.
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Old 05-14-2019, 04:21 PM
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I don't think .91 would be worthwhile at all. At 2000 RPMs if you went from 1:1 to .91 you would only drop to 1820 RPM.

Have you considered changing final drive ratios and then putting in an OD Trans.

Something like 3.54 with a .82 or .77 OD would work well.

John
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Old 05-14-2019, 04:28 PM
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Quote:
OK, I may not be the best person to be answering this, but I think you need to rethink this. The .82 and .77 are going to give you a lower RPM than a .91 5th gear at the same speed. The Richmond with the .77 being the lowest of the three.

I think his point is that a .82 fifth will be drop his RPMs too much. At 60MPH, he'd be turning only 1800 RPMs. That's probably too low unless he has a really mild camshaft.
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Old 05-14-2019, 06:20 PM
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Quote:
Originally Posted by GjC View Post
I have a CCX with the 4 speed Top Loader and I'm considering swapping out the tranny for a Tremec 5 speed (.82 OD) or the Richmond Super Street OD
(.77 OD), with either transmission is it possible to swap out 5th gear for higher ratio such as .91 for 5th gear? The rear end is a 2.88 and I have 26.5" diameter tires the car revs at 2450 at 60 MPH, I know that is probably a good RPM but I would like to drop it. The car has a 428 CJ and HP peaks at 5800 rpm's, if my calculations are correct with the rear end gears and tire diameter with a .91 OD the motor will be turning at 2000 rpm's at 60 MPH. Either tranny will give me good acceleration in 1st -4th gear it's the cruise ability on the highway I'm looking for (I do mostly highway driving), the .82 and .77 OD are to low with the 2.88 gears.
You need to do your maths again.
2450 at 60mph x .82 = 2009 rpm
2450 at 60mph x .91 = 2229 rpm

Can you see .91 as 5th gear would not be useful, since the drop in rpm from 4th gear is insignificant.
Gary

Last edited by Gaz64; 05-15-2019 at 03:24 AM..
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Old 05-14-2019, 08:02 PM
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I don't know where you live, but do you really only cruise at 60mph? Around here, even on the two lane black tops traffic moves along at about 70mph.

Anyway, If you're planning on cruising at 2,000, then you must have a fairly mild motor - which is good because they make boat loads of low end torque. The difference between .82 and .91 is so small, you probably won't notice it. But I do see your point.

Call Gordon Levy. He can build you a strong, light weight, and physically small T5 with the OD gear you're looking for. He can also give you a very low first, which would be nice with that 2.88 gear.
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Old 05-15-2019, 04:20 AM
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I personally think a Tremec TKO is stronger than the Richmond, FWIW. Years ago I had a Richmond in my somewhat mild 496ci 69 Vette and I blew 2nd gear. At the time there wasn't a TKO or anything else "supposedly" stronger than the Richmond.
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Old 05-15-2019, 09:16 AM
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I don't get the numbers that you state. For a 2.88 rear gear, 26.5 inch diameter tire, and in 4th (1:1) I get the engine should be turning at 2192 rpm at 60 mph. Are you sure you have a 2.88 rear end ratio?

based on your numbers, the rear end ratio would be more like 3.22.

Anyway, the Tremec TKO with .82 OD would have you at about 2009 rpm at 60, as Gary pointed out.
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Old 05-15-2019, 09:05 PM
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I don't get the numbers that you state. For a 2.88 rear gear, 26.5 inch diameter tire, and in 4th (1:1) I get the engine should be turning at 2192 rpm at 60 mph. Are you sure you have a 2.88 rear end ratio?

based on your numbers, the rear end ratio would be more like 3.22.

Anyway, the Tremec TKO with .82 OD would have you at about 2009 rpm at 60, as Gary pointed out.
Yes.

here's the formula.
https://www.rcnmag.com/d-i-y/calcula...atio-tire-size

are you sure your mph is correct ? taking measurement from a gps ? or your speedometer ?
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Old 05-21-2019, 06:08 AM
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The gear ratio on the Richmond are 1st(3.27), 2nd(2.13), 3rd(1.57), 4th(1.23), 5th (1.1)
I use GPS to verify the speed and 60 mph comes in under 2400rpms my speedo is 8 mph slow), re-checking the gear ratio and it is a 2.88 (slight miscalculation on the math-my bad). I want to avoid the rear-end swap, as for the motor the 428 has a slightly more aggressive cam than stock(Comp cam 284H) running 10.5-1 compression staged II Edelbrock heads and port matched Edelbrock 1-4V intake the motor dyno at 476hp at 5800 rpm's and 502 tq at 3600 rpms. I like the 2.88 because it gives me legs on the hwy and with the 3.27 1st gear the car launches well. I'm just looking to keep the car more in the power band and I was thinking by having a .91 5th gear the car stays in its power curve through the cam rpm range.
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Old 05-21-2019, 06:57 AM
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The T56 might suit you. I use the .82 TKO and long ago decided I would never "wear out" the motor with use. I have well north of 40k miles and it is happier than ever. If you are trying to save fuel, that is another story. Personally I think my motor prefers to run and not bog. Now, distance between fuel stops, that is another facet. I would go for a 42 gallon tank rather than drop my rpms.
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Old 05-21-2019, 06:59 AM
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I know you wish to avoid a rear gear change.
That said TKO 600 w/0.82 OD & 3.27 rear gear = 59 mph @ 2000 rpm.

At 5800 rpm
1st 2nd 3rd 4th 5th
49 74 109 140 171
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Old 05-21-2019, 10:15 AM
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Default Richmond Gear trans experience

I posted this to another related thread but thought I'd repost here. Nothing to do with gear ratios but everything to do with RG trans experience...

I too have a older Richmond 5 speed (5th is 1-1) with a Hurst shifter in my Cobra. I've had it in the car for close to 25 years now. If you asked me what's the #1 thing I'd change out on the car, I'd say it's the Richmond trans. I haven't done that yet just because I drive the car frequently and my garage time is focused on 2 other car projects (home built Ferrari GTO and Lambo Miura). I really like my Cobra and now enjoy driving it more than working on it.

Shifting on the Richmond is terrible. Some of that maybe the the Hurst shifter, but some is surely the trans. I've adjusted the shifter many times to get it to "best adjustment" which still leaves a lot to be desired. I do grind the reverse gear on 5th to 4th downshifts about 10% of the time even though I have many, many years of practice.

On high RPM up shifts from 2nd to 3rd, sometimes the trans gets into a state where it's basically locked up (I think maybe in 2 gears at the same time). If I let the clutch out when in this state, rear tires are locked which tells me the trans is locked up. I don't know what it is about high RPMs that triggers this but the issue doesn't happen on lower RPM shifts. The only way to get it out of this state is to bring car to complete stop, wiggle the shifter until it goes into reverse, and that must clear the other gear engagements. It's very dangerous (and embarrassing) to have to bring your car to a complete stop in moving traffic just to clear a faulty trans issue. If anyone else has had this same issue and found a permanent fix, I'd love to hear about it.

In addition to the poor shifting, I think the trans internals are of marginal quality. I've had to replace the output shaft bushing and a couple of syncros in about 40K miles of driving. I expect a much longer life from a trans than that. My Cobra is powered by a 300HP SBF so it's not like I'm throwing a bunch of HP and torque at the trans. I now regret fixing it versus swapping it out for a different trans when I had the trans out for repairs.

Oh well, it's the trans I have until I have the time and energy to replace it. It works good enough to get by I just thought I'd share my experience with others so they have some insight when thinking about using the Richmond 4+1 in their Cobra.
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Old 05-23-2019, 07:34 AM
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Joel I have the same problem with my Richmond gear 5 speed. It sucks when it happens at the drag strip. This is also a 5 speed and not a overdrive 4 speed. I thought it was my shifter that was the problem but after your thoughts maybe something is going on inside of the trans.

The box it come in said Bullet prof transmission. Broke on the first pass at the track on a mild 302. The T 5 I had in it never broke with a lot of hard use.
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Old 05-23-2019, 07:46 AM
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One more thought on overdrive stick trans. If the engine has much cam and the overdrive drops the rpm below the cams usable range you will not be very happy.
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Old 05-23-2019, 09:16 AM
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Quote:
Originally Posted by MAStuart View Post
Joel I have the same problem with my Richmond gear 5 speed. It sucks when it happens at the drag strip. This is also a 5 speed and not a overdrive 4 speed. I thought it was my shifter that was the problem but after your thoughts maybe something is going on inside of the trans.

The box it come in said Bullet prof transmission. Broke on the first pass at the track on a mild 302. The T 5 I had in it never broke with a lot of hard use.
Are you also using a Hurst shifter? Maybe a combination of poor shifter and a transmission vulnerability to the issue. Have you found a viable fix to prevent the issue? I'm guessing it would happen quite frequently on the drag strip given all 2nd to 3rd gear shifts would be high RPM.
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Old 05-23-2019, 10:34 AM
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Joel It is a Hurst shifter. But I modified a lot of parts to make it work. I have it in a 65 Mustang fastback. I did not want to cut the car up and wanted to use my console. I made a new tower mounting plate to lower it a bunch. The tower was also modified by using some internal parts from my original hurst shifter from the 4 speed. It works fine for shifting no matter what RPM. It is hard to shift fast compared to the old T10. The problem seems to come into play when I am speed shifting and no lift on the gas pedal. I thought it was the shifter not moving the lever for the gear it was in but moving the next gear lever locking it in 2 gears. You have to come to a complete stop and play with the shifter to get it unlocked. If I ever get the time to figure it out I will let you know. Other that being hard to shift compared to other trans. I just love the gear ratios of the trans. By the way the thing worked good other than being hard to shift compaired to other trans. The problem started after several years of use. I have a lot of experience with manual trans and this problem is weird.

Last edited by MAStuart; 05-23-2019 at 10:41 AM..
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Old 05-23-2019, 07:56 PM
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Joel - have you watched this?

https://youtu.be/6UnFDaAdBaM

I was planning to do this to mine this past Winter, but got sidetracked with a broken valve spring and subsequent repair.
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Old 05-24-2019, 10:16 AM
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Originally Posted by Moriarty View Post
Joel - have you watched this?

https://youtu.be/6UnFDaAdBaM

I was planning to do this to mine this past Winter, but got sidetracked with a broken valve spring and subsequent repair.
I hadn't seen that video before although I've seen the inside of my RG trans. Thanks for mentioning it as it contained a lot of good information.

I wish I'd seen the video before replacing a couple of syncros in my RG as I would have known to check for additional things. In addition, I would have used different syncros that just replace with RG syncros. From the video, it looks like the transmission should have internal prevention from engaging two gears at once if the shifting shafts and detents are working correctly. Apparently, my transmission is faulty in that area as it does appear to allow at times multiple gear engagements on the 2nd to 3rd gear upshift. In other words, what I thought was a shifter issue maybe a transmission issue.

I'll have to investigate further to understand possible ways to fix the issue. I still have a dilemma though. Do I invest more time, energy, and money in the RG trans or give up on it and go with something else
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Old 05-24-2019, 12:49 PM
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Do I invest more time, energy, and money in the RG trans or give up on it and go with something else
You don't really have any other options do you unless you want to change the rear end gear ratio. Presumably you have 2.88 or maybe 3.07 gears. If you go with a Tremec 600 you might be able to get away with 3.07 gears but I think 3.31 or even 3.54 gears are much preferred.
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