Why do certain v6 Fieros have gauges that only go up to 80mph (Page 1/2)
Decaffrican OCT 20, 05:07 AM
I bought my 85 v6 Fiero knowing it wasn't a GT but figured the difference between trims came from the difference in engine/suspension/bodypanels...? I'm pretty new to the car scene, and even though I now own one, I'm still a hardcore newbie when it comes to knowledge about Fieros.
oneinch OCT 20, 07:20 AM
This is not an answer to your question. Just a comment. .... My '88 Formula has a 120 speedo. I would prefer the 80 speed myself because of the greater detail in the dial. I don't drive 80 so I don't need speed markings that high. I know I know. The 120 speedo looks cooler. Here's a shot at an answer: the 4's get 80, the 6's get 120.

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Stanton
'88 Formula, red on gray

fierofool OCT 20, 07:24 AM
The 85 V6 was available in the GT trim and the SE trim. Both had the 85mph speedometers. All 4 cylinder Fieros had the 85mph speedometers. The 120mph speedometers didn't appear until 86 and was available in the GT trim, as well as the SE trim.

The 86 and 87SE trim is identical to the 85GT body. The 86 and 87 SE's were also available with a choice of 4 or 6 cylinders even though they had the aero trim package like the 85GT and they had the 120 speedometeer. The 'bumperpad' 86 which is the same as your 85SE trim however, only came as a 4 cylinder. I believe it had the 85mph speedometer.
olejoedad OCT 20, 08:02 AM
The good news is that the 85 mph and 120 mph speedos are plug and play as far as interchangeablity.

My 86 SE (V-6/4 speed) came with an 85 mph speedo, but it was quickly replaced.
RWDPLZ OCT 20, 08:24 AM
Many cars had speedometers that only went to 85 MPH, due to a NHTSA mandate during the 70's oil crisis

http://www.classic-car-hist...om/85-mph-speedo.htm
Wichita OCT 20, 08:48 AM

quote
Originally posted by RWDPLZ:

Many cars had speedometers that only went to 85 MPH, due to a NHTSA mandate during the 70's oil crisis

http://www.classic-car-hist...om/85-mph-speedo.htm



Basically RWDPLZ nailed it.

Back in the 70's, the top speed limit on the Interstates and Highways was 55mph as the National Speed Limit. They did up it to 65mph in the 80's.

It wasn't until 1996, when the Federal Government gave the speed limit decisions back to the respective states. Now you will see 70 to 75mph as very common, with even some 80-85mph speed limits.

From my understanding, that cars in the 70's - 80's and even to the 90's the engines were engineered and tuned to maximum efficiency at 55mph because of the National Speed Limit law enacted in the 70's.




ZaraSpOOk OCT 21, 02:25 PM

quote
Originally posted by oneinch:

This is not an answer to your question. Just a comment. .... My '88 Formula has a 120 speedo. I would prefer the 80 speed myself because of the greater detail in the dial. I don't drive 80 so I don't need speed markings that high. I know I know. The 120 speedo looks cooler.




I can only recall being 90 or over twice in the 30+ years I have owned mine.
But then I drive two lane blacktop over 90% of the time
Reading the 120 speedo is indeed difficult, and the red line at 55 is of no help today, speed limits here are usually 60 on two lane, 70 on 4, 55 is rarely the speed limit.

FWIW, the speedo on my Vette goes to 200
I've done 165, 140 or more numerous times
Dennis LaGrua OCT 21, 02:37 PM
That 80 mph speedometer is a real inconvenience. I only have it on my 85GT ragtop but on the turnpike in my 87GT in some segments speeds of over 90 are common. I travel almost always over 80 mph. The good news like Joe has said the 120 mph gauge console drops right in.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 10-21-2021).]

MarkS OCT 21, 03:40 PM
Joan Claybrook '79. It took a few years to undo that one.
Dennis LaGrua OCT 21, 05:26 PM

quote
Originally posted by MarkS:

Joan Claybrook '79. It took a few years to undo that one.



Yes as head of the NHTSA she was the one responsible to the 80 mph speedometers, the collapsible front bumpers, mandatory air bags, removal of hood ornaments, and imposing tough crash standards. Like most Socialists she insisted that government knew what was best for everyone and car prices skyrocketed because of these mandatory changes.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "