Tach Doesn't Work Wondering Whats My Rpm's On The Freeway

83GTMUSTANG · 05-17-2005, 03:09 AM

EVERY SINCE I PUT MY MSD ON MY TACH DOESN'T WORK (TACH ADAPTER ON ITS WAY) AN IVE UP GRADED ALOT ON MY STANG :HEADERS EXAUST 3.73 GEAR SO MY RPM BAND HAS RISEN AN I CANT GO BY THE SOUND OF MY ENGINE ANY MORE OR MY SPEEDO CAUSE ITS WAY OF SO MY QUESTION IS WHATS MY RPM'S AT 70 MHP WITH 3.73'S AN 16-55-245'S................

~The Jester~ · 05-17-2005, 10:08 AM

Need to know tire diameter (in inches) and in what gear are you talking? I'm GUESSING the tires are about 26.25" or so, and assuming you mean overdrive, that puts you about 2300 RPM at 70MPH, according to the calculators here on MW.

83GTMUSTANG · 05-17-2005, 12:18 PM

In Fifth Gear, 26.61 Diameter Tires............thanks

Ieatcamaros · 05-17-2005, 07:02 PM

Tire diameter is 26.61". The 5th gear ratio is .68. You would be doing 1923 RPM at 60MPH and 2243 RPM at 70 MPH. At 80 MPH, you would be turning 2563 RPM.

83GTMUSTANG · 05-17-2005, 07:04 PM

Thanks Guys Fo Your Reply's

~The Jester~ · 05-18-2005, 08:35 AM

WOW! That was a hell of a guess I threw up there! LOL

Even a blind squirrel finds an acorn once in awhile. hehehehehe

Glad we could help you out. Get the tach fixed, that's the best way to tell for sure.

05-17-2005, 03:09 AM	#1
83GTMUSTANG N-V-ME Join Date: May 2005 Location: SOUTHFIELD,MICHIGAN Posts: 155	Tach Doesn't Work Wondering Whats My Rpm's On The Freeway EVERY SINCE I PUT MY MSD ON MY TACH DOESN'T WORK (TACH ADAPTER ON ITS WAY) AN IVE UP GRADED ALOT ON MY STANG :HEADERS EXAUST 3.73 GEAR SO MY RPM BAND HAS RISEN AN I CANT GO BY THE SOUND OF MY ENGINE ANY MORE OR MY SPEEDO CAUSE ITS WAY OF SO MY QUESTION IS WHATS MY RPM'S AT 70 MHP WITH 3.73'S AN 16-55-245'S................ __________________ 88' LX MUSTANG: LINCOLN ROTORS , AIR SUSPENSION FRONT AND REAR, SUBFRAMES, ROLL CAGE, 92' BLOCK, MSD 6AL, ACCEL 8.8 WIRES, ACCEL COIL, EDELBROCK F4B INTAKE (PORTED),2 IN. 4 HOLE SPACERS, HOLLEY 600 CARB.,HOLLEY BLUE FUEL PUMP AN REGULATOR, E 303 (.498 IN. 220 DUR.) CAM, (.535 IN. OF LIFT W/ 1.72 SCORPIN ROLLER ROCKERS), PORTED E7'S, FLOWTECH 1 5/8 LONG TUBE HEADERS, 2 1/2 IN. H PIPE, 2 CHAMBER FLOWMASTERS WITH 3 IN.DUMPS, T-5, 3.73 GEARS, 5 LUG AEROSTAR AXELS, 245-45-17 96' COBRA WHEELS

05-17-2005, 10:08 AM	#2
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Tach Doesn't Work Wondering Whats My Rpm's On The Freeway Need to know tire diameter (in inches) and in what gear are you talking? I'm GUESSING the tires are about 26.25" or so, and assuming you mean overdrive, that puts you about 2300 RPM at 70MPH, according to the calculators here on MW. __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

05-17-2005, 12:18 PM	#3
83GTMUSTANG N-V-ME Join Date: May 2005 Location: SOUTHFIELD,MICHIGAN Posts: 155	Re: Tach Doesn't Work Wondering Whats My Rpm's On The Freeway In Fifth Gear, 26.61 Diameter Tires............thanks __________________ 88' LX MUSTANG: LINCOLN ROTORS , AIR SUSPENSION FRONT AND REAR, SUBFRAMES, ROLL CAGE, 92' BLOCK, MSD 6AL, ACCEL 8.8 WIRES, ACCEL COIL, EDELBROCK F4B INTAKE (PORTED),2 IN. 4 HOLE SPACERS, HOLLEY 600 CARB.,HOLLEY BLUE FUEL PUMP AN REGULATOR, E 303 (.498 IN. 220 DUR.) CAM, (.535 IN. OF LIFT W/ 1.72 SCORPIN ROLLER ROCKERS), PORTED E7'S, FLOWTECH 1 5/8 LONG TUBE HEADERS, 2 1/2 IN. H PIPE, 2 CHAMBER FLOWMASTERS WITH 3 IN.DUMPS, T-5, 3.73 GEARS, 5 LUG AEROSTAR AXELS, 245-45-17 96' COBRA WHEELS

05-17-2005, 07:02 PM	#4
Ieatcamaros Domestic Rice really sucks! Join Date: Apr 2002 Location: KY Posts: 973	Re: Tach Doesn't Work Wondering Whats My Rpm's On The Freeway Tire diameter is 26.61". The 5th gear ratio is .68. You would be doing 1923 RPM at 60MPH and 2243 RPM at 70 MPH. At 80 MPH, you would be turning 2563 RPM. __________________ The sig says it all.

05-17-2005, 07:04 PM	#5
83GTMUSTANG N-V-ME Join Date: May 2005 Location: SOUTHFIELD,MICHIGAN Posts: 155	Re: Tach Doesn't Work Wondering Whats My Rpm's On The Freeway Thanks Guys Fo Your Reply's __________________ 88' LX MUSTANG: LINCOLN ROTORS , AIR SUSPENSION FRONT AND REAR, SUBFRAMES, ROLL CAGE, 92' BLOCK, MSD 6AL, ACCEL 8.8 WIRES, ACCEL COIL, EDELBROCK F4B INTAKE (PORTED),2 IN. 4 HOLE SPACERS, HOLLEY 600 CARB.,HOLLEY BLUE FUEL PUMP AN REGULATOR, E 303 (.498 IN. 220 DUR.) CAM, (.535 IN. OF LIFT W/ 1.72 SCORPIN ROLLER ROCKERS), PORTED E7'S, FLOWTECH 1 5/8 LONG TUBE HEADERS, 2 1/2 IN. H PIPE, 2 CHAMBER FLOWMASTERS WITH 3 IN.DUMPS, T-5, 3.73 GEARS, 5 LUG AEROSTAR AXELS, 245-45-17 96' COBRA WHEELS

05-18-2005, 08:35 AM	#6
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Tach Doesn't Work Wondering Whats My Rpm's On The Freeway WOW! That was a hell of a guess I threw up there! LOL Even a blind squirrel finds an acorn once in awhile. hehehehehe Glad we could help you out. Get the tach fixed, that's the best way to tell for sure. __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

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