That's what I'm lookin for, something that bad ass on the street, light um up, but also want to be able to take it on road trips Posted using the Full Custom H.A.M.B. App!
Fab32 @post #16 has the right approach. Stimpy @ post #23 makes an important point at the end of his comments that I would like to expand upon also. If you plan on a street machine, street tractability is far more important than high RPM power. The cam needs to provide smooth torque band from a minimum 2000RPM. That is a "RV" or "torquer" cam with about 245 degree duration advertised. That cam will still pull fine above 4000RPM which is tighter than you really what to spin it for very long. It may not make for impressive bench-race conversation but will provide a great all-round driver. Back to the gear set, Fab32 mentioned the standard modern setup, 2000RPM @70MPH. If you spend any time on the highways, freeways, etc. you want you engine to be revving around the lower end of it's torque curve where it can live forever. There, you still have plenty of headroom in the torque band for passing or to keep from getting run over by a Toyota doing 85MPH. The need to do burnouts will become secondary when you compare time on the road stopping and starting and turning corners versus time spent doing tire frying burnouts. For burnouts any final drive gear will get you there with enough power, but you may need to adjust the brake bias to the front to get them broken loose if you don't have enough. For reference we have a 49 Buick with a modified straight eight/700R4/3.08 posi /27" tire. Goes 75MPH @2100RPM. It has plenty of grunt with a 4&5/16" stroke but feels a little long legged, I'm switching to 3.42's. It doesn't do burnouts just a little squeal on takeoff, but it's no pig, it just pulls longer in each lower gear and breaks a hundred just going around a Semi. My 36 Ford with a Nailhead and a Gear Vender OD, 3.73's and 28" tires seems a little short geared even in overdrive. But that coupe will come around on me if I'm not careful just by stabbing the throttle. It could stand a taller gear. Also have a 54 GMC with a very strong six w/ 4sp hydro & .72 OD/ 3.55 final & 29" tire. It gets 1st & 2nd gear rubber and can still knock down 41 second miles, mile after mile @2800RPM. That's 88 MPH, & I wouldn't change a thing on that rig. So from the empirical evidence I've gleaned from my own experience, I say GM has it just about right with their 3.42 final ratio. Set your priorities, you know what you have for a rig and make your choice, You'll be the driver. Best Regards and Good Luck with all your endeavors, KB.
A wise man would learn to do the gear calc without a gear calculator. RPM divided by gear ratio gives wheel RPM. diameter of tireX3.14/12 gives feet per revolution. feet per revolution time number of revs of wheel give number of feet per minute feet per minute x 60 gives feet traveled per hour that divided 5280 gives MPH.
RPM Gear 1000 1500 2000 2500 3000 3500 4000 4500 5000 3.06 6.17 9.25 12.33 15.41 18.50 21.58 24.66 27.74 30.83 1.63 11.57 17.36 23.15 28.94 34.72 40.51 46.30 52.08 57.87 1.00 18.87 28.30 37.73 47.16 56.60 66.03 75.46 84.90 94.33 0.70 26.95 40.43 53.90 67.38 80.85 94.33 107.80 121.28 134.76 MPH RPM Gear 1000 1500 2000 2500 3000 3500 4000 4500 5000 3.06 6.78 10.17 13.55 16.94 20.33 23.72 27.11 30.50 33.88 1.63 12.72 19.08 25.44 31.81 38.17 44.53 50.89 57.25 63.61 1.00 20.74 31.11 41.47 51.84 62.21 72.58 82.95 93.32 103.69 0.70 29.62 44.44 59.25 74.06 88.87 103.69 118.50 133.31 148.12 MPH RPM Gear 1000 1500 2000 2500 3000 3500 4000 4500 5000 3.06 7.12 10.68 14.24 17.80 21.36 24.92 28.48 32.04 35.60 1.63 13.37 20.05 26.73 33.42 40.10 46.79 53.47 60.15 66.84 1.00 21.79 32.68 43.58 54.47 65.37 76.26 87.15 98.05 108.94 0.70 31.13 46.69 62.25 77.82 93.38 108.94 124.51 140.07 155.63 MPH RPM Gear 1000 1500 2000 2500 3000 3500 4000 4500 5000 3.06 7.39 11.09 14.78 18.48 22.17 25.87 29.56 33.26 36.96 1.63 13.88 20.81 27.75 34.69 41.63 48.56 55.50 62.44 69.38 1.00 22.62 33.93 45.23 56.54 67.85 79.16 90.47 101.78 113.08 0.70 32.31 48.46 64.62 80.77 96.93 113.08 129.24 145.39 161.55 MPH
Sorry about the formatting. I can't seem to get it right, but there it is, from fun-to-economy. 4.10, 3.73, 3.55, 3.42.
I have a 700R4 with a 3:42 rear gear and 29 inch tall rubber. I run the torque converter lockup on a separate switch so it has to be engaged manually- it makes the transmission like a 5 speed. I find I only use the lockup on the open road above 60 mph- never on two lane roads. With the converter locked up it turns 1950 rpm at 70 mph. It has enough bottom end for me Posted using the Full Custom H.A.M.B. App!
Do I understand your post correctly to mean the switch actually activates the lock up function in the converter any time the switch is "on"? That would require manually flipping the switch to unlock when coming to a stop. If so, have you considered wiring the lock up in such a manner that the manual switch merely 'opens' or 'closes' the normal lock up circuit , allowing the 'automatic' lock up/unlock to function whenever the switch is 'closed'? And, in turn, when you do not want lock up, it doesn't occur because the circuit is open. The benefit being, even with lock up selected, that would eliminate the need to manually unlock the converter when coming to a stop. If I have misinterpreted your post, please excuse this reply.
I have to manually lock and unlock the converter by throwing the switch-yes you have to remember to unlock the converter when you are getting off the freeway - if you don't unlock it-well you know it . I set mine up this way because I didn't like the way the factory setup locks up at about 40 mph if you are not 'on it ' a bit Posted using the Full Custom H.A.M.B. App!
I worked the numbers out differently. I have a Ford product and a 3550 5-speed with a .63 OD. I have 3.5, 3.8, and 4.10 pumpkins. At the stop light grand prix, I will only run up to 60 mph and I only want to make one shift. So by working the numbers, the 4.10 would require two shifts to hit 60mph at red line, and the 3.5 is too fast (mph) and therefore has a slower elapsed time to 60 mph. So the 3.8 is the sweet spot for me. Can't believe it took Detroit so long to add 5th gears. My car ('69) came with a 4-speed and a 3.0. You could either cruise on the highway OR , with a gear change, win at the lights, but not both. The change to a 5-speed was night and day. I run strong at the lights and have driven to California and back averaging 25+ mpg.
That should be wired through the 4th gear switch, so lockup only works in 4th, even if you forget to turn it off. Your setup is dangerous, and should be changed, before someone gets hurt. Posted using the Full Custom H.A.M.B. App!
It only locks in 4th gear-But I ask-how would I get hurt if I left it locked up?- The only time I forgot-The car still slows down to a stop-it just seems to chug a little as it slows down to remind you to unlock it.
I guess I'm going to go against the majority of those who responded and say I wouldn't run a 3.73 or lower with a 700r4 and a 26" tire. The long smokey burnouts you want will be tough to do with the low rear gear, and low first gear of a 700r4. Your engine will run out of rpm's on a long burnout, and you'll need to shift to 2nd pretty quickly. And the combination wont give you the cruise rpm advantage of the OD 4th gear I'd like either. I think a 3.42 or 3.55 would be a perfect combination of good launch and good highway cruising too.
No I havent rear ended anyone-And will all due respect,I am not seeing your point-I do appreciate your concern The car doesnt have the ablity to roll on out of control if that is what you mean. Locking trhe converter doesnt put the car on Auto-Pilot
Looking at your avatar I guessed on a combo 3800 pounds, 290 HP Here are 3, 0 to 1/2 mile, graphs with 3.08, 5.38 and 4.56 gears.
I'd vote for something around a 4:11 gear. Changed the gears in my 05 Mustang GT to 3:73. Everyone was telling me go with 4:10 gearing but I was afraid highway performance. Now that the gears are in there wish I had went with the 4:10!
Your initial statement was not clear on when it locks up. You clarified after. Also, if it is chugging, when you are slowing down, it might still be locked, even when it is not in 4ht. Did you use the 4th gear contact switch to provide the ground for the converter lockup solenoid, or does the ground wire go elsewhere? If it only can lock in 4th, regardless of switch position, that is the factory setup, on most 700R4's (there were some variants that could lock in 3rd. as well). Having a converter that stays locked, all of the time, regardless of gear, brakes, or throttle position, is an accident, and lawsuit waiting to happen.
With all the info, spread sheets, calculators, and personal experience you guys have sent my way I'm going to go with the 4.10-1, it will be a blast on the street and with the 700r4 tans. It will get down the highway nicely. Thanks a lot for the info! Posted using the Full Custom H.A.M.B. App!
(Quote) Did you use the 4th gear contact switch to provide the ground for the converter lockup solenoid, or does the ground wire go elsewhere? .[/QUOTE] Thats a good question-I have had this transmission in the car and operating for about 9 years and roughly 35,000 miles-I don't recall exactly how I did hook it up to be honest but I do know I was under the direction of the transmission shop that built the transmission for me He told me what to do and it has seemed to work good all this time
Try to come to a complete stop, somewhere safe, without turning off the switch. That will tell the tale.
the proper way is thru the trans and the brake switch and you can always use the brakeswitch as the failsafe disconnect
but look at the trans ratios on the vette 6-8 speed and you see why , they do the reverse instead of OD it they start out with a very underdriven trans ( kind of what we do for semis massive ratios to get out of the hole and OD for the top 2 holes and use 18 gear ratios to do it , bob tailing I do not use the bottom 9 gears as I do not need the multiplication of torque and can start out in 12th gear but will smoke the tires doing so ) with a vette I wouldn't be suprised it you could start off in 3rd gear without choking , more companies are going to more gear ratios for smoothness and to get rid of the Od whine and clutch problems ( harmonics causes engagement problems in clutches ) .
I would put 4.88s in it and smoke those 20" till they blow! You can't put a price on FUN Why do people ask these questions? Pat
my price in fun cost me a diff ( crappy stock gm unit ) and a $500 fine for disturbing the peace ( only thing they could get me on since it was private property .)
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