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#1 |
Registered User
Join Date: Jun 2007
Location: Smyrna, GA
Posts: 709
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Idol question
Im trying to figure out if my Tach is correct.
What is normal RPM while sitting still w/ the truck in Drive? Mine show's about 800-900 RPMs at a steady idol. It reads 3000 rpm at 65 mph. (I have a TH 350 w/ a 3.07 rearend) THNX-
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Rottenwood Garage 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun |
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#2 |
Registered User
Join Date: Dec 1999
Location: Old Mission, MI, USA
Posts: 2,510
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Re: Idol question
If it is a factory tach, it almost definitely reads high. Several hundred rpm high at 3000 rpm is pretty normal.
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Tim |
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#3 |
Registered User
Join Date: Jun 2007
Location: Smyrna, GA
Posts: 709
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Re: Idol question
Sorry, It's an after market Sun Pro.
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Rottenwood Garage 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun |
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#4 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Idol question
Any figure you want it to be. You can set the speed where you want with the idle screw. 800 to 900 seems a little high for drive. What is the rpm in park?
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#5 |
Registered User
Join Date: Nov 2004
Location: Nebraska
Posts: 762
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Re: Idol question
If it is an auto that is too high, sounds correct for a 4spd though. My blazer seems to always be low when in drive, like 500-600 rpm. It sometimes drops to 400 when the a/c is on.
Try this link, someone posted it a while back: http://www.ringpinion.com/Calculators.aspx |
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#6 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: Idol question
american idol is on the fox network
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#7 |
Dave's not here, man
Join Date: Jun 2004
Location: Winder, Georgia
Posts: 2,000
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Re: Idol question
![]() To answer your question, I have mine set to ~800
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- 2014 VW Jetta - 2015 VW Jetta - 1966 Ford F-250 Last edited by dave2953; 04-26-2008 at 02:38 AM. |
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#8 |
Registered User
Join Date: Aug 2006
Location: Bakersfield,CA
Posts: 7,893
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Re: Idol question
mines about 900 in park and 650 in gear (SB350/TH350)
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
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#9 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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Re: Idol question
depending on the rear tire size, 2500 is more acurate for 25 MPH with 3.07's.
I would say you are a bit high, and your idle sounds like it is reading high too. If it were that high at idle, then it'd be about 1000 - 1100 in park, and that would start to border line slaming into gear. |
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#10 | |
Registered User
Join Date: Jun 2007
Location: Smyrna, GA
Posts: 709
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Re: Idol question
Quote:
How do I adjust the idol, or the tach? It's one of the smaller Sun Pro tach's and I have no idea how to change it.
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Rottenwood Garage 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun |
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#11 |
Dave's not here, man
Join Date: Jun 2004
Location: Winder, Georgia
Posts: 2,000
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Re: Idol question
My Sun Pro tach has a a place on the back that will let you set the "zero" adjustment when the engine is off, and it has a selection switch for the number of cylinders. Those are the only two adjustments that I know of.
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- 2014 VW Jetta - 2015 VW Jetta - 1966 Ford F-250 |
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#12 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Idol question
Not the tach -the carb set screw.
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#13 |
Registered User
Join Date: Apr 2007
Location: King City, Ontario, Canada
Posts: 974
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Re: Idol question
dave is right, there is only two ways to adjust the tach, the # of cylenders, and the zero adjustment
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#14 |
Son of a gun
Join Date: Jan 2007
Location: Hot Springs, Arkansas
Posts: 1,636
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Re: Idol question
I don't think he needs to adjust the tach, he needs to adjust his idle speed screw.
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Bill BEATERS ARE NEATER |
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#15 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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Re: Idol question
why do you think it's idling high? His tach is reading way too high at a specified speed.
When you run it in park, and put it in drive, does it clang into gear. or maybe lean over from engine torque... or does it just drop the idle a tad and act like a normal vehicle? You guys are forgetting, these tachs are stupid cheap and not exactly high quality. I figured when Snap On bought out sunpro, that there quality would go up... but nothing. Last edited by Longhorn Man; 04-27-2008 at 02:17 AM. |
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#16 |
Wishin' I had more money!
Join Date: Feb 2007
Location: Eugene, OR
Posts: 1,242
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Re: Idol question
I have a th350 with a 3.73 rear end and mine's at 2900rpm at 65. My th350 with the 2.73 rear end was at about 2300 at 65.
I think your tach is reading slightly high. Also, my idle is at about 600 in gear. |
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#17 |
Registered User
Join Date: Jun 2007
Location: Smyrna, GA
Posts: 709
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Re: Idol question
idol at park = 1000 rpm's
idol sitting still in drive = 800 rpm's idol at 65 mph = 3000 rpm's doesnt seem to be slamming into drive. it's a nice transition. i think my tach is reading too high-
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Rottenwood Garage 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun |
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