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Old Dec 19, 2004 | 12:21 PM
  #1  
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From: Fayetteville, NC
Car: 84 Z28 Convertible 2 Seater
Engine: Dart Little-M SBC 400
Transmission: Pro-built Automatics 700R4
Axle/Gears: Strange Engineering 3:73
TACH Reading Off

I Change over to a 145mph Speedo now my guages or screwed up.The TACH is reading about 1500 more rpms than the actual engine speed. It usually ides at 900-1000, now she is close to 2500 rpm. What could have caused this mishap?
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Old Dec 19, 2004 | 01:11 PM
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all stock tachs suck, my stock is 400rpm off , get aftermarket it is the only way to be sure.
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Old Dec 19, 2004 | 05:09 PM
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From: MN
Car: 85 SC, 86 Berlinetta
Engine: V6, V8
Transmission: 700r4, 700r4
Great, I just bought a cluster so I would have a tach to protect my engine. That's why you see those pictures of the extra tach hooked up to the side.
Can you adjust the stock tach?
Are the gauges off as well?
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Old Dec 19, 2004 | 07:30 PM
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From: Kissimmee, FL
Car: 1991 Camaro RS
Engine: 357cid
Transmission: T5 Swap
Axle/Gears: 10bolt 7.5" 3.23 soon to be 3.73
tachs dont protect you engine.. a rev limiter will. no you cant adjust it
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Old Dec 19, 2004 | 07:34 PM
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From: Fayetteville, NC
Car: 84 Z28 Convertible 2 Seater
Engine: Dart Little-M SBC 400
Transmission: Pro-built Automatics 700R4
Axle/Gears: Strange Engineering 3:73
Originally posted by Saigon_Bob
tachs dont protect you engine.. a rev limiter will. no you cant adjust it
I have to agree, you will need a MSD Rev Limiter to "protect: your engine. You have wasted/invested money in the wrong area.....
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Old Dec 19, 2004 | 08:44 PM
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From: MN
Car: 85 SC, 86 Berlinetta
Engine: V6, V8
Transmission: 700r4, 700r4
Actually, I didn't mean that the tach itself would protect the engine (bad wording on my part) but that I would know when it's reaching it's upper limit.
If it's off by 400-500 RPM then I would be overreving it in on a regular basis.

By the way, does anyone have any experience with the shift lights? Would that be a way to know when to shift? I have an auto anyways but I sometimes hold the shift back until it's up there. I have a newly rebuilt engine and tranny and want to keep an eye on it.
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Old Dec 20, 2004 | 10:55 AM
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From: Fayetteville, NC
Car: 84 Z28 Convertible 2 Seater
Engine: Dart Little-M SBC 400
Transmission: Pro-built Automatics 700R4
Axle/Gears: Strange Engineering 3:73
Could it be possible that I might have a V6 tach hooked up to a V8 and those 2 extra cylinders is causing the rpm to read higher than they are. If the tach dosent know the difference and registers the two extra cylinders as a faster rpm since its going by the spark of the ign system.
Just a thought:

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Old Dec 20, 2004 | 11:16 AM
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From: Kissimmee, FL
Car: 1991 Camaro RS
Engine: 357cid
Transmission: T5 Swap
Axle/Gears: 10bolt 7.5" 3.23 soon to be 3.73
Originally posted by DTL504
Could it be possible that I might have a V6 tach hooked up to a V8 and those 2 extra cylinders is causing the rpm to read higher than they are. If the tach dosent know the difference and registers the two extra cylinders as a faster rpm since its going by the spark of the ign system.
Just a thought:

well the tachs are off anyhow but yes that is the problem with using a v6 tach with a v8 engine


Originally posted by Scorpner
Actually, I didn't mean that the tach itself would protect the engine (bad wording on my part) but that I would know when it's reaching it's upper limit.
i was being sarcastic, but if you have an auto why would you hold it back from shifting...
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Old Dec 20, 2004 | 11:31 AM
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From: MN
Car: 85 SC, 86 Berlinetta
Engine: V6, V8
Transmission: 700r4, 700r4
Isn't it necassary to shift an auto "manually " to get the most out of it? Why do they make ratchet shifters and slap sticks?
I thought autos shifted too early when you wanted the most out of it.
:shrug:
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Old Dec 20, 2004 | 12:32 PM
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Originally posted by Scorpner
Isn't it necassary to shift an auto "manually " to get the most out of it? Why do they make ratchet shifters and slap sticks?
I thought autos shifted too early when you wanted the most out of it.
:shrug:
Recalibrate the trans to shift when you want it to under WOT. Now-a-days people want the manual auto shifters for the "cool factor" they think it gives or for special purpose. For a street driven vehicle those shifters are pretty much useless.
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Old Dec 20, 2004 | 12:49 PM
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From: Lima, OH
Car: '89 Formula 350 & '86 Z28
Engine: L98 & 355ci
Transmission: 700r4 in both
My car is slower shifting it manually, it doesnt shift when I actually shift it.

How many RPM are you wanting to shift at?
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Old Dec 20, 2004 | 03:07 PM
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From: Kissimmee, FL
Car: 1991 Camaro RS
Engine: 357cid
Transmission: T5 Swap
Axle/Gears: 10bolt 7.5" 3.23 soon to be 3.73
Originally posted by Scorpner
Isn't it necassary to shift an auto "manually " to get the most out of it? Why do they make ratchet shifters and slap sticks?
I thought autos shifted too early when you wanted the most out of it.
:shrug:
ratchet shifters allow you to shift when you want easier than the stock one, but if you put it in drive it still works like normal....... i know that if i was to control the shift which i have a few times..... i shift b4 the trans does.....
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Old Dec 20, 2004 | 03:18 PM
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From: Lima, OH
Car: '89 Formula 350 & '86 Z28
Engine: L98 & 355ci
Transmission: 700r4 in both
Automatic shift points can be adjusted to wherever you like them, regaurdless of shifter.

In non-electronic transmissions its all about govenor pressure overcoming throttle pressure to get an up shift. This is what changing the weights on your govenor does.
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Old Dec 20, 2004 | 04:28 PM
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From: MN
Car: 85 SC, 86 Berlinetta
Engine: V6, V8
Transmission: 700r4, 700r4
Originally posted by Morley
Recalibrate the trans to shift when you want it to under WOT. Now-a-days people want the manual auto shifters for the "cool factor" they think it gives or for special purpose. For a street driven vehicle those shifters are pretty much useless.

You make it sound easy to recalibrate the shift points. How easy is it?
Are these shifters useful on an off road situation? Where and why?
What shifter would you recommend if you did use one?
The reviews I've seen make them sound like a waste. Just one more thing to tinker with or go wrong.
I liked the one on my Goat, it was simple and foolproof.

Originally posted by SweetS10v8
My car is slower shifting it manually, it doesnt shift when I actually shift it.

How many RPM are you wanting to shift at?
That's never happened when I've used a ratchet shifter, it always shifted when I wanted it to.
Actually I don't even have all the stats on my new engine yet.
But I've almost always had to hold back the shift to reach the recommended shift RPM.
Doing this manually does open up opportunity to damage the engine on a mis-shift.
So with the set up I have where the engine and tranny were built together- I shouldn't ever have to shift it manually? -Ever?


[QUOTE]Originally posted by Saigon_Bob
ratchet shifters allow you to shift when you want easier than the stock one, but if you put it in drive it still works like normal....... i know that if i was to control the shift which i have a few times..... i shift b4 the trans does..... [/QUOTE

O.k. what would be the purpose of controlling the shift if you shifted before the tranny normally would? Are you trying to keep it in a certain power band and why?

Thanks for your comments but I'm becoming more confused on this subject.
What really is the purpose of the ratchet shifter?

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Old Dec 20, 2004 | 04:35 PM
  #15  
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From: Oregon, Roseburg area
Car: 88 camaro
Engine: carby 350
Transmission: t-5 from v6 car
The ratchet shifter is so you don't accidentally go from first to third gear.
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Old Dec 20, 2004 | 05:50 PM
  #16  
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Originally posted by Scorpner
You make it sound easy to recalibrate the shift points. How easy is it?
Are these shifters useful on an off road situation? Where and why?
What shifter would you recommend if you did use one?
The reviews I've seen make them sound like a waste. Just one more thing to tinker with or go wrong.
I liked the one on my Goat, it was simple and foolproof.
A good shift kit will have an assortment of springs and govenor weights to change the line pressures and throttle pressures shift points. If you are talking about a 700R4 trans you may also want to look into getting the corvette servo. If you are looking to rebuild also get a kit with more clutch packs than stock.
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Old Dec 20, 2004 | 08:36 PM
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From: Kissimmee, FL
Car: 1991 Camaro RS
Engine: 357cid
Transmission: T5 Swap
Axle/Gears: 10bolt 7.5" 3.23 soon to be 3.73
ratchet shifters are useful for racing but are mearly for a cool factor on teh street
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