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Toploader...Close or Wide ratio??
I ordering a complete 2x4bbl 462 Sideoiler Stroker and Toploader from Bill Parham @ Southern Automotive, But i`m not sure about having close or wide ratio gears in the transmission. Bill says thats with 500hp you don`t really notice any difference? I`m not doubting his experience but would like any feed back from you guys.
I was considering a Richmond 5speed but Bill has advised the toploader. My car has a 3.77 rear end, which i will be changing to 3.31 or even a 3.07 and my tires and wheels are being upgraded to 275 or 295 40 17 for more traction and grip. I had a long chat with Bill and he is a real FE expert, he has shown me the way to go with a suitable engine spec for my car. And we share the same passion for the Rolls Royce Merlin Aero engine normally found in WW11 Spitfires and P51D Mustangs. There is alot of work to be done to fit a FE engine into my car, but i have a ex Aston Martin engineer prepared to carry out the work. But with a 6-8 week build time and then shipping time it will be a long long but exciting wait to sample the Real 427 experience!! Thanks |
Dude, I have a 3.31:1 and a close-ratio toploader behind a mild (475HP) sideoiler. Most advised the wide ratio, but all the high performance Corvettes I've had (and my last cobra, 460-powered) had the close-ratios, and I loved 'em. I decided on a close-ratio, and was also a little concerned, until I drove it for the first time, and I wouldn't have it any other way...with the torque it has, there's no problem moving away from a dead stop, and first and second gears are soooo long. Also, the shifts are just "right there", with little rpm drop. All in all, a very sweet experience. Go close!
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mr0077 said it....
Generally speaking if you have a heavy car with tall gears a close ratio is tricky from a stop. You don't. |
I have a tremec which is not CR; after you become used to the way your car accelerates, you will cry for a close ratio! In a Cobra, less shifting and longer legs are the trick on a road course. Enjoy.
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Comparing the close and wide ratio toploaders, shifting at 6500 rpm, your rpm will drop from 250 to 350 more between gears with the wide as opposed to the close. With you having so much hp/torque, you probably would not even notice any difference. For all out performance, the close ratio would be quicker, but again, because of the cars hp/weight ratio, I don't think there would not be that much difference.
Running the close with a 3.54 diff would be comparable to a 3.07 diff with a wide rato, as the first gear is deeper at 2.78 as opposed to 2.32 for the close. With the richmond, the first gear-second gear spread is kind of big, such that your rpm drop (6500-4190)would be 520 more compared to a close ratio(6500-4710), and about 300 more compared to a wide ratio(6500-4480). Pick your transmission first, then pick the appropriate diff ratio for that corresponding 1st gear ratio. |
Would anyone have any objections to a close ratio toploader, 3.07 (or 3.31) rear and an aluminum flywheel? We are not that worried about all out acceleration. We would like the ability to cruise at a comfortable speed with a toploader, I don't think acceleration will be much of a problem.:) From a "driveability" standpoint, would anyone prefer the close over the wide toploader.
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Dude-3.31 gears or lower,Wide Ratio! 2.32 first in the CR is too low for your gears.You'll hate it.Especially if you have a aluminum flywheel.
I sent my CR Nascar T/L to David Kee.He did his road race thing to it and changed it to a W/R. Made it another car. On another note-i was 6 inches from a idleing Hurricane & Mark IX Spit a couple of weeks ago.I still have a smile on my face. |
3:31 gears/wide ratio here :)
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3.31/wide here. Also from Bill
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I see a trend......
I started out with a 3.54/wide and then after 3000 miles switched to a 3.31/wide. I believe that is what ERA recommended all along - of course I knew better having built all of ZERO Cobras before. |
I had a wide ratio for a long time and switched to a close ratio - finally.
I should have done that much ealier. The gap from 3rd to 4th was just too big. But, well maybe driving in Germany was different. I liked to shift into 4th at 200 kph with the close ratio instead of shifting at 180 kph with the wide ratio. BTW, nobody except me felt the difference ... dominik |
Dude,
Thanks for asking this question. I've been wondering about the CR vs. WR debate myself. It appears that you and I will have virtually the same motor (462 stroker, dual quads, etc.) from the Parhams. Will you be using an aluminum flywheel? I'm probably not (if I add one more costly goody to this engine, my wife will kill me). After riding in a few cars, I've decided on the CR with a 3.31 rear differential. It doesn't really matter than much to me. Either combination is guaranteed to scare the hell out of me. %/ :3DSMILE: Keith :) |
Will you guys that are running 3.31s and CRs tell me what rpm you are turning in 4th gear at 60 mph and 80 mph?
Does anyone have 3.31s and a Tremec? What rpm are you turning in 5th gear at 60 and 80? Thanks Mike |
Mike, My speedo isn't precise, but I'm pretty close to the numbers shown in the ERA manual...3.31, 295/50-15's on the rear...about 2500 rpm @ 60 and 3300 rpm @ 80
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Ken-
Thanks for the info., it is helpful. I am trying to decide between the Top Loader and Tremec. I like the idea of 5th gear on the Tremec. Are there no Tremec guys out there?? Mike |
Mike - I have the tremec tko and 3.31 rear. Engine runs 3000rpm at 100mph in 5th. It's quite tall - makes for great cruising, but acceleration really takes a drop from 4th to 5th. Since it's doing around 135 mph at 6000rpm in 4th, maybe I shouldn't be so worried, but them Porsches take some convincing.
If I did it again, I would go for the TKOII with the 0.8 5th gear. |
Wilf-
Thanks. By the way you've got a great looking car, but I think they put the steering wheel and roll-bar on the wrong side!! Thanks again. Mike |
Golly, Mike - I just took a look at those pictures - must've posted them the wrong way around? Steering wheel is always on the side of the car I get into so I guess it must be OK.
BTW - forgot to mention the 1st gear in the tremec, at 3.27, is too short, I just get wheelspin if you floor it in this gear, fast get-aways need a short shift into second to get any real action. Must be the penalty for that nice overdriven 5th? Apart from that, and wishing I had gone for the alternate 5th gear, I like it just fine. |
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