LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Tach accuracy

Thread Tools
 
Search this Thread
 
Old Oct 4, 2006 | 10:37 AM
  #1  
Mr.Camaro's Avatar
Thread Starter
Teching In
 
Joined: Aug 2006
Posts: 40
Likes: 0
Default Tach accuracy

I was browsing through the MadZ28.com and i noticed that he said near desired rev limited:

(Keep in mind that the stock tach may show 300-400 RPM more than actual RPM!)

Is this true?
Reply
Old Oct 4, 2006 | 10:41 AM
  #2  
Jditlfm's Avatar
12 Second Club
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (26)
 
Joined: Apr 2005
Posts: 1,456
Likes: 0
From: Brockport NY
Default

I would say like 100-200 rpm's, i installed a shift light and i noticed this. shift light comes on at 5800 and the tach shows about 6000
Reply
Old Oct 4, 2006 | 11:26 AM
  #3  
flame's Avatar
TECH Fanatic
20 Year Member
iTrader: (13)
 
Joined: Oct 2004
Posts: 1,169
Likes: 3
From: Waterloo, Ontario
Default

Yep same here idle is 900 on datamaster dash tach reads 1100
Reply
Old Oct 4, 2006 | 11:34 AM
  #4  
1994Z28Lt1's Avatar
TECH Resident
iTrader: (1)
 
Joined: Sep 2005
Posts: 833
Likes: 0
From: Elko MN
Default

knowing in gm that tach accuracy thing is probably intentional because obviously the pcm has to know the exact rpm to operate correctly but the guage doesn't necessarily have to show it

maybe a little error on the safe side for engine reliability especially when i dont even hit the stock rev limiter in my car (5886rpm) until the tach reads about 6100 but in 1st gear you hit it right about 5800 because im sure the tach cant keep up

the inaccuracy of the tach seems kind of intentional to me
Reply
Old Oct 4, 2006 | 01:34 PM
  #5  
Ed Wright's Avatar
9-Second Club
iTrader: (1)
 
Joined: Feb 2002
Posts: 3,397
Likes: 9
From: Tulsa, OK
Default

It's true. The higher you go the further it's off. Evidently the error is percent, not RPM. Most look about 100 high at idle, but when mine was stock I shifted it at 6000, the tach showed almost 6500. I now shift it at 7K, the tach lays on the peg for some time before the shift happens. I shift a local customer's car at 6600, it also pegs the tach.
Reply




All times are GMT -5. The time now is 04:57 AM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE