05-30-2014 | #111 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,698
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Re: 4.10 gears...not what I expected.
Using 19s and 3.55s, the stock trans speedo gear puts me at about 3mph low on the speedo when running 70mph. Something along the lines of 3-4% off which is acceptable to me.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
05-30-2014 | #112 |
Join Date: Dec 2003
Location: Chicagoland,IL
Posts: 2,679
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Re: 4.10 gears...not what I expected.
They must've installed it wrong.
Have DD in the 441 auto Z for about 10 years works great no issues. Pete
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05-30-2014 | #113 | |
Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
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Re: 4.10 gears...not what I expected.
Quote:
Yes in bracket racing, if both cars run their dial in, the car that crosses the finish line first gets the win, so long as you dont "breakout" and run a lower ET than your "dial-in". I remember being in a money class for eliminations. There were cars that sat on the line for many seconds before they got to launch. I see them launch wheels up in my rearview mirror and then charge by me at the finsh line. The guy was choked that he lost though. Using the Pro tree in "heads up" drag racing whichever car gets to the finish line without "red-lighting" wins. The ET you run in this type of drag racing doesnt matter. ET is meaningless in heads up because the timers for your own lane dont start until your vehicle moves, and end when your car breaks the beams at the finish line. On the quicker shifting. Having quick shifts on a manual trans increases the amount of time that the drive wheels are putting power to the ground. The only way rpm drop during an upshift would increase appreciably is if shifted VERY slowly. Slow enough that the car actually loses speed during the shift, otherwise rpm in a manual trans car is pretty constant. This is where an automatic has an advantage, power is always being transmitted to the rear drive wheels during upshifts. But thats a different discussion.
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05-30-2014 | #114 | |
Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
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Re: 4.10 gears...not what I expected.
Quote:
Thanks.
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peace Paul ZR-1 Net Registry Member #1494 |
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05-30-2014 | #115 |
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Re: 4.10 gears...not what I expected.
OR, better yet, is what is the center wheel to pavement height - allowing for some "squish" factor?
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
06-01-2014 | #116 | |
Join Date: Oct 2013
Location: Wichita Falls,Tx
Posts: 604
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Re: 4.10 gears...not what I expected.
Quote:
Rears are 335/30/19 (26.8")
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Clint & Sherry 1994 ZR-1 White/Red #152 (sold) 1991 ZR-1 Callaway Aerobody #1332 (sold) 1990 ZR-1 Red/Red #952 (sold) 2002 Z06 Torch Red/Mod Red widebody |
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06-01-2014 | #117 | |
Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 815
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Re: 4.10 gears...not what I expected.
Quote:
On the quicker shifting issue, I think about it in terms of inertia. The difference between a power shift, and a granny shift, is that in a power shift the gas pedal is on the floor throughout the shift. When the clutch is disengaged, the rpms shoot up, the shift is made while this is happening, and when the clutch re-engages, the power is higher than before, therefore helping the engine rpm stay up higher in it's power band. In the granny shifted car, shifted at the same rpm, as the clutch disengages the driver lets off the gas until the clutch is re-engaged. As it re-engages the rpms are lower than before, and pulled down further by the next gear. This loses inertia. The engine has to climb that rpm mountain again, three times during the race, (twice in a three speed car). It goes with out saying that when you are letting off the gas three times during the race, even for milliseconds, that is slowing you down. Wear and tear on the gearbox is obviously the downside to power shifting. I've been through 3 transmissions doing this. So, now that I'm a Grandpa, I shift like Granny tells me to. |
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06-01-2014 | #118 | |
Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
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Re: 4.10 gears...not what I expected.
Quote:
Semantics, quickest car, with the best reaction time wins. I agree 100% with you during a proper "powershift". Including the factors that you describe, which are 100% correct, there is also the slight torque multiplication that occurs as the friction materials slip as they come together as the clutch is released. This multiplicarton is only apparent while the clutch disc and the flywheel are turing at different rates. Once the rates are equalized, only gearing supplies the multiplication. I apologize for the "granny" shifting term. No matter anyones age, they deserve the same respect (perhaps more) that someone of another age. USA ZR-1 thanks for the specs.
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peace Paul ZR-1 Net Registry Member #1494 |
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06-01-2014 | #119 |
Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 815
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Re: 4.10 gears...not what I expected.
Semantics are important if you want your meaning to be clear.
I've never understood the semantics of the term "torque multiplication". I've seen it used, mostly, to describe the advantage the automatic transmission has, at launch, in the quarter mile. The torque converter allows enough slippage to let the engine come higher into it's power band before the car starts moving. So that you have more power available at launch. The automatic has other advantages, and disadvantages, but I don't see how torque is literally "multiplied" in any way. Semantics |
06-01-2014 | #120 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,698
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Re: 4.10 gears...not what I expected.
I have 19s on the back. The fronts are 18s. Just measured the rears sitting there w ~ 35psi, they stand at 26.25". Size is 325/30/19. These are the Nitto Invos which I like quite a bit. Good wet, fairly quiet, and grab pretty well on hard shifts.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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