cygnusx1 Posted December 2, 2006 Share Posted December 2, 2006 Right Mike. Since we are way off the dangling mystery of the original post (no offense original poster)...My brother posed a question to me the other night about torque, gearing and top speed. He is a big fan of diesel. He touts the torque of them. He asked if it is better to have torque or HP for a top speed. I told him that HP makes top speed. He disagreed and said that with alot of torque you could just keep changing gears to keep in the torque band and keep increasing speed. He was dissapointed when I told him the torque gets divided through gears. The wheel torque would decrease with every up gear change. Was I correct? I think so. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 2, 2006 Share Posted December 2, 2006 Correct. The wheel torque decreases with each shift, but speed, or amount of work being done, is increasing, thus the horsepower at the rear wheels stays the same regardless of which gear you're in (that's my understanding of this). The torque is what moves the car, and the horsepower is the result of this. This is why it seemed so "foreign" to me too accept the concept of using a higher gear ratio to increase acceleration. This, to me, is like lining up for a race and taking off in 2nd gear because I've got a high-torque motor. Now if the tires are spinning all through 1st gear, then I could understand, and this may be at the heart of the issue. He was dissapointed when I told him the torque gets divided through gears. The wheel torque would decrease with every up gear change This is why you'll see situations where the top speed of a specific car is actually achieved in 4th gear even though you have a 5th gear available. The decreased torque of the higher gear will not overcome the increasing drag of the air, whereas the increased torque of the lower gear will overcome more of the increasing drag, and allow the car to achieve a higher terminal velocity. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 2, 2006 Share Posted December 2, 2006 Think power, not torque. Gearing needs to be set up to keep the engine spinning in the meat of the power band. Using steeper rear gears will help you accelerate faster if it keeps you in the power band longer. A car with a wide power band will go faster if the gears are spaced farther apart. The RPM drops more between shifts but hey, thats OK because the engine is still operating at a good power level. Less time shifting means more time accelerating. A car with a narrower power band needs more gears spacing more closely together to get the engine into the power band quickly and to keep it there. Going to 4th gear will improve the top speed of a car only if dropping one gear brings the engine RPM closer to the HP peak. Ideally you want the transmission to keep the engine spinning at the HP peak as the car speed changes. This will give you the maximum theoretical acceleration. Quote Link to comment Share on other sites More sharing options...
Forrest Posted December 2, 2006 Share Posted December 2, 2006 Nope, the 260Z 2+2 came with a 3.36 R200. I know, it's not on the list that you looked at, but it really did come in that car. Jon, thanks very much for sharing this. This is pretty darn useful information...I have actually seen a 2+2 260z, but never a 79 280zx 2+2 4spd. That seems like it's probably the rarest combo possible. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted December 2, 2006 Share Posted December 2, 2006 I may have found a 3.36 diff... awaiting confirmation. But the cost of shipping may make it too pricey. If that deal doesn't work out, the guy I'm dealing with here knows someone who has 30-40 old Z-cars laying around... so there is still some hope. I'll know Monday. This guy might have a bunch of stuff I want. The bad thing is I just spent a crap-load of money on parts from Summit. Sheesh... I'm about to go BUST with all the $$$ I'm putting into this thing!! Quote Link to comment Share on other sites More sharing options...
Overkill Z Posted December 3, 2006 Author Share Posted December 3, 2006 Low gearing is for low torque/high RPM motors. High gearing is for high torque/low RPM motors. Right? and Z's are much higher torque then hp Quote Link to comment Share on other sites More sharing options...
v80z Posted December 20, 2006 Share Posted December 20, 2006 Well I got the 3.364 rear end at the house. I bought it from Danny's Datsuns in Oregon, I know I know. Well I cracked the case to check it out and it turns out to be the 3.54. I called him and he " Oh yeah the 3.54 is what they call a 3.364". I said yeah whatever. I will keep it. But I could have got one of those locally for alot less. Anyway the internals looks good. I will clean it up and swap it out for the welded 3.90. Should have a little more highway manners. And can always swap back if needed. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 20, 2006 Share Posted December 20, 2006 Well I got the 3.364 rear end at the house. I bought it from Danny's Datsuns in Oregon, I know I know. Well I cracked the case to check it out and it turns out to be the 3.54. I called him and he " Oh yeah the 3.54 is what they call a 3.364". I said yeah whatever. I will keep it. But I could have got one of those locally for alot less. Anyway the internals looks good. I will clean it up and swap it out for the welded 3.90. Should have a little more highway manners. And can always swap back if needed. HaHa... sounds like when I paid top dollar for a pair of "rust free" doors from him, only to get them with rust bubble blisters at the bottom of the doors.... his remark after contacting him for a return, " oh, those are what I consider rust free".... yea, right. They were returned.... Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted December 20, 2006 Administrators Share Posted December 20, 2006 You know how them Oregonians are... ya just can't trust 'em Quote Link to comment Share on other sites More sharing options...
Ledphoot Posted December 20, 2006 Share Posted December 20, 2006 If I can find a deal I'd love to go to a 3.90 or 4.11 in my 260z All the Dragstrips close to home here are 1/8 mile... Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted December 20, 2006 Share Posted December 20, 2006 im currently running a 3.54 in my Turbo'd 280z.. ive never driven anything else.. but that makes sense.. you know I can't break the tires loose by mashing the gas pedal in first second third or beyond?! ive always wondered.. oh maybe its not tuned properly.. but then I started thinking.. 1) my altitude of 5,800 ft. + non standard temp = very high density altitude 2) my 3.54 gearing.. the turbo LOVES it and highway driving is awsome.. if i were to race from a dead stop.. I would be destroyed from 0-65mph .. however.. around 65mph the turbo spools up like all hell and 65-130mph (maybe speedo error) is amazing... car is fast (top speed) but a slow (acceleration) Quote Link to comment Share on other sites More sharing options...
twoeightythreez Posted December 20, 2006 Share Posted December 20, 2006 That's good info. 260z2+2. I'll be looking around, as I recently put a 4.11 in my z and then did a turbo swap, when it's tuned I take it it's gonna be a wheel-spinning, go-nowhere monster. I also heard there was a NISMO 3.08 R200 at one time? Quote Link to comment Share on other sites More sharing options...
Forrest Posted December 20, 2006 Share Posted December 20, 2006 "Oh yeah the 3.54 is what they call a 3.364". I said yeah whatever. You should have told him "I guess you're what they call a rip-off artist." Quote Link to comment Share on other sites More sharing options...
auxilary Posted December 20, 2006 Share Posted December 20, 2006 taller gearing is more suited for turbo applications because that way you stay longer in the gear, and able to push more power at sustained high rpm. To greatly exaggerate this example, let's say it takes a turbo l28et with a big turbo 2 seconds to go from 5000rpm to 7000rpm in 3rd gear with a 4.11 differential. That means that maximum power output is generated for 2 seconds in that gear, until you shift to 4th, and drop down to lower rpm. swap gears to a 3.54, and that time between 5k and 7k rpm in 3rd grows to 3 seconds. maximum power output is sustained for 3seconds before the next shift downside of taller gears on turbo cars is crappier launch (more bog) did that make sense at all? Quote Link to comment Share on other sites More sharing options...
Careless Posted December 29, 2006 Share Posted December 29, 2006 so if i have a 4speed 76 280z, does that mean i have a 3.36 gear aswell? and who wants to buy it from me =) Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 29, 2006 Share Posted December 29, 2006 so if i have a 4speed 76 280z, does that mean i have a 3.36 gear aswell?and who wants to buy it from me =) Nope.... read it again.... Quote Link to comment Share on other sites More sharing options...
Careless Posted December 30, 2006 Share Posted December 30, 2006 Nope.... read it again.... 1972 through 1976 Factory Four/Five Speed Transmission Ratios 72/76 two piece case U.S. Non-US F4W71B FS5C71B 1. 3.592 2.906 2. 2.246 1.902 3. 1.415 1.308 4. 1.000 1.000 5 n/a 0.864 RearGear 3.36 3.900 (72 thru 76) Quote Link to comment Share on other sites More sharing options...
mrcheeze36 Posted December 30, 2006 Share Posted December 30, 2006 Nope, the 260Z 2+2 came with a 3.36 R200. I know, it's not on the list that you looked at, but it really did come in that car. This is what J. Soileau RB26zcar was talking about Careless. I can confirm this...I pulled a 3:36 R200 from a 74' 260Z 2+2. Quote Link to comment Share on other sites More sharing options...
Careless Posted December 30, 2006 Share Posted December 30, 2006 so my 280 coupe has what, then ? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 30, 2006 Share Posted December 30, 2006 so my 280 coupe has what, then ? Should be a 3.54 R200. Quote Link to comment Share on other sites More sharing options...
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