redliterunner

I'd seen several explainations as to why some cars have the 145 mph speedo, and some cars of the same vintage got the 110.

What's the correct answer?

Best explaination I've heard so far is that cars ordered with Z rated tires got the 145, while those ordered with V or H rated tires got the 110.

a mack6

iTrader: (1)

yea id like to know as well...I have an RS with the 110 MPH speedo and its limited to 112. I mean its not like i plan on going over that anyway, but still i got the V8 which i would assume could get to like 125 atleast...

redliterunner

My car hits the limiter smack on 130mph. I'm still surprised that it will actually go that fast (TPI 305 convertible). It would probably go a little faster were it not limited. Mine has the 145 speedometer.

If you've got a V-8, you would probably go at least as fast as mine, because my motor is pretty tired.

3rdgenstm

you have a vert is why you have a 110. The G92 RPO triggered the 145 speedo.

redliterunner

My convertible has the 145 mph job.

chuck88iroc

My 1988 convertable has the 145 speedometer and didn't come with Z-rated tires but rather V rated. If I remember right the V rated tire was the highest rating you could get with the cars until 1989 when they were replaced with the Z rating. I think the 145 mph speedometer was more the result of the rearend option.

Chuck

GTA Jim

FWIW, back in the late 70's or early 80's, one of the car manufacturers was sued by the surviving memberrs of a mans family. He was travelling well over the maximum speed rating of the tires on his car. As a result one tire blew out and the driver was killed.

Despite arguing that the guy was going way over the legal posted speed limit, the court still found the automaker at fault and they had to pay a large settlement.

Since then, most if not all manufacturers have made sure that the tires on a car can handle the speed the car will go. In other words, if a car comes without V or Z rated tires, it won't have a 140mph speedo and most likely will have a limiter..

I tried to find the case on the net, but I can't remember which automaker it was or exactly when it was so i didn't have much luck

Here's a quote from a website that deals with defective tire litigation...

http://www.alllaw.com/articles/perso...eTireLit_2.asp

-----------------------------------------------------------------
A tire speed rating reflects the outer speed limits at which the tire can be safety driven. It is now common industry practice to equip vehicles with tires that are speed rated at something greater than the maximum speed capability of the particular vehicle.

redliterunner

So do you feel that the speedo type was based somehow on the tire speed rating?

My car has no axle upgrade. It's a 2 series open diff. No disk brakes on back.....yet.

I've poked around the web and cannot find a speedometer related option code at all on these cars. So saying that it was an option might not be quite correct.

Even the 1LE had an option code (obviously), though it could not be checked on the order sheet. It resulted from checking other options on the order sheet. Right?

3rdgenstm

When it (1LE) first appeared in '89 you had to order the G92 with IROCZ coupe to trigger the 1LE. This required several items to be included: oil cooler, 4WDbrakes, dual cats and the 245/50/16 tires. It also gave the choice of the 350/ A4 or the 305/ M5 TPI options. All of these vehicles had 145 speedos. If the car was ordered with air (C60), then it was a street vehicle, if no C60 then it was a true 1LE with all the 'race' goodies: aluminum drive shaft, big brakes, fuel tank baffles, special shocks, and deleted fog lights and radio.

In 1988, any IROC with the B2L or LB9 package got the 145 regardless of tires or axle.

In 1990, the tires were the factor. You could have the TPI engine of your choice with the 15" IROC wheels. If the 15's were ordered a 115 was installed. If the upgraded tires were installed, then the 145 was installed.

I couldn't find anything on 91 and 92 other than the B4C's all got the 145 due to the B2L package.

3rdgenstm

All '88s had the 145 as long as it was a TPI vehicle. Nothing else decided it.

chuck88iroc

That sounds reasonable to me. I was just pretty sure it wasn't based on the speed rated tires.

Chuck

Dans87GTA

iTrader: (1)

im sorry but i have never seen a 3rd gen with a 145 mph speedo i have always seen 140 mph is that what all you mean? or are some really 145 just wondering kinda confused

911rsq

Z28's and IROC's got the 145mph speedo's. It is kind of funny because everyone keeps saying this is why, or this is why not. Those that are giving examples are using examples from the Z28 and IROC pacakages as to "why" the car has the 145 speedo. It is true that the TPI cars have the 145's, but you have to have the Z28 to have the TPI. Convertible "option" doesn't matter either.
A Mack6 has a RS vert....110 speedo
redliterunner has a z28 vert.....145 speedo

You are not as confused as you think you are.... The last number on the gauge is in fact 140, but if you look, there is another "notch" past the 140 mark, making it a 145mph speedometer.

911rsq

Here's mine from my car as an example of the "145" mph cluster

3rdgenstm

Not all Z's and IROCs were TPI cars. TPI wasn't the standard engine for Zs until 91.

redliterunner

So the 145 speedo install was the result of the tpi setup. Who'da thunk it.

I can't think of any exceptions.

Does anyone have any evidence to dispute this?

Kinda funny. Usually you hear G92 being the cause.

BTW my speedo actually has '145' printed next to the last mark as well as '5' printed next to the first.

okfoz

For Firebirds it may be different, but both lines seemed to use some of the same logic in some cases.

Here is what I have figured out with the help of the parts & Illustration catalogs. This has been discussed before, however.

<p style="margin-top: 0; margin-bottom: 0"><font size="6">87-92 Speedometer/ Tachometer Combinations Does not include
Digitals</font></p>
<hr>
<p style="margin-top: 0; margin-bottom: 0"><font size="6">1987</font></p>
<div align="center">
<center>
<table border="1" width="90%">
<tr>
<td bgcolor="#FFFF00" height="15">
<p align="center" style="margin-top: 0; margin-bottom: 0">Engine</p>
</td>
<td bgcolor="#FFFF00" height="15" align="center">
<p style="margin-top: 0; margin-bottom: 0">Transmission</p>
</td>
<td bgcolor="#FFFF00" height="15" align="center">
<p style="margin-top: 0; margin-bottom: 0">Speedometer</p>
</td>
<td bgcolor="#FFFF00" height="15" align="center">
<p style="margin-top: 0; margin-bottom: 0">Tachometer</p>
</td>
</tr>
<tr>
<td height="16">
<p style="margin-top: 0; margin-bottom: 0">305 LG4 (4BBL)</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4, M5</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">85 mph</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</p>
</td>
</tr>
<tr>
<td bgcolor="#FFFFCC" height="16">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</p>
</td>
</tr>
<tr>
<td height="16">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">M5</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</p>
</td>
<td height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</p>
</td>
</tr>
<tr>
<td bgcolor="#FFFFCC" height="16">
<p style="margin-top: 0; margin-bottom: 0">350 L98 (B2L) (TPI)</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</p>
</td>
<td bgcolor="#FFFFCC" height="16" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</p>
</td>
</tr>
</table>
</center>
</div>
<p style="margin-top: 0; margin-bottom: 0">&nbsp;</p>
<hr>
<p style="margin-top: 0; margin-bottom: 0"><font size="6">1988 &amp; 1989</font></p>
<div align="center">
<center>
<table border="1" width="91%">
<tr>
<td width="23%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Engine</p>
</td>
<td width="18%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Transmission</p>
</td>
<td width="20%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Rear Gear</p>
</td>
<td width="10%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Speedometer</p>
</td>
<td width="30%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Tachometer</p>
</td>
</tr>
<tr>
<td width="23%">
<p style="margin-top: 0; margin-bottom: 0">305 LO3 (TBI)</td>
<td width="18%" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4, M5</td>
<td width="20%" align="center">
<p style="margin-top: 0; margin-bottom: 0">All</td>
<td width="10%" align="center">
<p style="margin-top: 0; margin-bottom: 0">120 mph</td>
<td width="30%" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</td>
</tr>
<tr>
<td width="23%" bgcolor="#FFFFCC">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</td>
<td width="18%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</td>
<td width="20%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">2.73 (GU2)</td>
<td width="10%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">120 mph</td>
<td width="30%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</td>
</tr>
<tr>
<td width="23%">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</td>
<td width="18%" align="center">
<p style="margin-top: 0; margin-bottom: 0">M5</td>
<td width="20%" align="center">
<p style="margin-top: 0; margin-bottom: 0">3.08 (GU4)</td>
<td width="10%" align="center">
<p style="margin-top: 0; margin-bottom: 0">120 mph</td>
<td width="30%" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</td>
</tr>
<tr>
<td width="23%" bgcolor="#FFFFCC">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</td>
<td width="18%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</td>
<td width="20%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">3.23 (GU5)</p>
<p style="margin-top: 0; margin-bottom: 0">3.27 (GW6)</td>
<td width="10%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</td>
<td width="30%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</td>
</tr>
<tr>
<td width="23%">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</td>
<td width="18%" align="center">
<p style="margin-top: 0; margin-bottom: 0">M5</td>
<td width="20%" align="center">
<p style="margin-top: 0; margin-bottom: 0">3.45 (GM3)</td>
<td width="10%" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</td>
<td width="30%" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</td>
</tr>
<tr>
<td width="23%" bgcolor="#FFFFCC">
<p style="margin-top: 0; margin-bottom: 0">350 L98 (B2L)</td>
<td width="18%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</td>
<td width="20%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">All</td>
<td width="19%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</td>
<td width="31%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</td>
</tr>
<tr>
<td width="23%">
231 V6 Turbo</td>
<td width="18%" align="center">
A4</td>
<td width="20%" align="center">
All</td>
<td width="19%" align="center">
140 mph</td>
<td width="31%" align="center">
5500red / 8000max</td>
</tr>
</table>
</center>
</div>
<p style="margin-top: 0; margin-bottom: 0">&nbsp;</p>
<hr>
<p style="margin-top: 0; margin-bottom: 0"><font size="6">1990 - 1992</font></p>
<div align="center">
<center>
<table border="1" width="90%">
<tr>
<td width="25%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Engine</p>
</td>
<td width="21%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Transmission</p>
</td>
<td width="22%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Speedometer</p>
</td>
<td width="32%" bgcolor="#FFFF00" align="center">
<p style="margin-top: 0; margin-bottom: 0">Tachometer</p>
</td>
</tr>
<tr>
<td width="25%" align="left">
<p style="margin-top: 0; margin-bottom: 0">305 LO3 (TBI)</p>
</td>
<td width="21%" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4, M5</p>
</td>
<td width="22%" align="center">
<p style="margin-top: 0; margin-bottom: 0">120 mph</p>
</td>
<td width="32%" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</p>
</td>
</tr>
<tr>
<td width="25%" bgcolor="#FFFFCC" align="left">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</p>
</td>
<td width="21%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4, M5</p>
</td>
<td width="22%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">120 mph</p>
</td>
<td width="32%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">5000red / 6500max</p>
</td>
</tr>
<tr>
<td width="25%" align="left">
<p style="margin-top: 0; margin-bottom: 0">305 LB9 (TPI)</p>
</td>
<td width="21%" align="center">
<p style="margin-top: 0; margin-bottom: 0">M5</p>
</td>
<td width="22%" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</p>
</td>
<td width="32%" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</p>
</td>
</tr>
<tr>
<td width="25%" bgcolor="#FFFFCC" align="left">
<p style="margin-top: 0; margin-bottom: 0">350 L98 (B2L) (TPI)</p>
</td>
<td width="21%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">A4</p>
</td>
<td width="22%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">140 mph</p>
</td>
<td width="32%" bgcolor="#FFFFCC" align="center">
<p style="margin-top: 0; margin-bottom: 0">5500red / 8000max</p>
</td>
</tr>
</table>

</center>
</div>

redliterunner

Aarrgh! Now we're back to axle ratios possibly being the determiner. I'll have to check my console, but I'd be surprised if my car had a 3 series gear in it.

Yeah, chev and pont could've be different, but likely were not.

redliterunner

There's a 6000 mile 89 iroc convertible on ebay right now TPI, 5 speed, with a 115 mph speedo.

What's it all mean, Professor?

GTA Jim

Hmmmm.... I'm guessing, but it looks to me like someone swapped in a speedo with low mileage on the clock and never noticed the original speedo they took out went to 145

ajmclean

i saw an 87 z28 (not iroc) convertible with 85MPH speedometer

and the car was TPI with A4,

i thought all TPI cars got 145MPH in 87

but the only explanation i could think of is that it might
be an 86 custom job

Ant

My 89 Iroc says 145 on the speed. I would post the pic but it says the file is to big.

NCGiant

Mine is a TPI vert, and has the 110 speedo

labrat

If it's an 87 Z28 vert, the only engine tranny options were TPI 305/5 speed, or Carbed 305/Auto.

Since carbed 305's got the 85 MPH speedo in 87, the car in question must have had the carb swapped for the TPI.

ajmclean

the car has (Tuned Port injection) printed on the back,
so i guess the stock was a TPI,but i heared that in 87
there were auto TPI with the 190 hp,

or may be like u said he put in it a carb or
may be a 350

Bill Speed

OK, I was a bit confused as to the 145 vs 140 speedo, looking at the picture above, the '145' still is imprinted "140" at the top end.
Mine ends at 140, shown below, and is a 1989 car.

I figured the speedo a sure sign of the 305 vs 350, at least in my case. (350 TPI vert, dealer ordered it seems) I had a theft car w no list of option numbers to go over. I need to do the Historical Service option to get this stuff, hopefully I can get in on that soon. Work here JUST now picked up from next to nothing.

I got my car up to 130MPH in the express lane one afternoon, though that's not something I made a habit of, my buddy was at the wheel and he's experienced on several motor vehicles
I have the 16" wide tread Bridgestone Potenzas

Bill

Bill Speed

I can resize it in my camera's editing software, this offer for anyone having pic problems, I can likely edit it to work for ya
Just drop an email to billschwenke@aol.com, but leave out any virus' I just had major Spyware problems knock one PC offline UGH, major pain
Sorry, too, about the double post, but I'd like to help up the pic factor here, so I offer my service free. I'll email a working pic back, rather then post it
BILL

911rsq

Bill,
I think the original question is in ref to the Camaro speedometer. It has been pointed out that the Firebird/TA speedo's are a little different. The Camaro speedos have and extra "notch" after the 140mph mark. Some of the Camaros even have a little "145" next to that mark. It doesn't appear that yours has this. That is where the "confusion" about 140 or 145 comes in. Camaro's had both, so some say 140 mph and other people call it the 145. Mine only says 140, but the mark is there.......so 145 it is.....
P.S. that needle has seen the far side of the little notch on more than 1 occasion.....

okfoz

When the higher MPH speedos came out in 1986, the Camaro had 145, and the Firebirds got 140. The base speedo was still 85 Mph until 1987.


John

redliterunner

After all this, frankly, I'm not convinced that anyone can point to one option or condition and say, without a doubt, that it's the reason this or that car got this or that speedo. For every suggestion so far, it's been pretty easy to find contradictory evidence, on Camaros at least.

It seems, after all, that the different speedo installations were pretty much arbritrary.

Some guys are using the "this or that car must have been tampered with, therefore it doesn't comply with my theory. Personally, I really doubt most of these cars have been tampered with that much, aside from wheels and light engine mods.

To top it all off. I met a fellow this weekend with a car identical to mine, except for exterior color and speedo capacity. I've owned mine for a long time, and I doubt the speedo was ever messed with.

WAIT! Perhaps car color was the determiner.....black cars got 145 and white cars got 115.

camaro05

iTrader: (1)

there are a lot of good points in this thread. I always thought that the 350s came with the 145 and the 305s came with 110. That is the way my 92 RS and 91 Z is. If you look at ebay and other cars for sale, It seems that the 350 cars have the 145 speedo. maby this is for 91/92 cars only becasue of the people on here with pre 91 vehicles with a 305 and 145 speedo. Just my

Air_Adam

I always thought it was just the L98 or LB9/T5 cars that got the 140mph speedo?

Bandit400

Also include B4C and I bet that would be correct...at least with the '90-92s. I am not nearly as familiar with the pre-90s.

ajmclean

according to what i know about camaros

1985 all cars got the 85 MPH

1986 at the beggging of year most got the 85MPH
but later 145MPH was introduced only on
TPI engines regardless of transmission

1987 the 85MPH was used on cars equipped with LG4 engines.
the 145MPH was used on both Lb9 305 and L98 350
(but what confused me is that i saw a z28 vert with
85MPH and stock TPI)

1988 The 115MPH was the base on TBI cars 305, and also
on automatic Lb9 TPI ,

the 145MPH was used on both the manual 305 Tpi
and the 350 L98

1989 the 115MPH used on 305 Tbi and on all convertibles
regardless on engine

the 145MPH was used on 305 TPi and 350 tpi
except for verts

1990 The 115MPH speedometer was on convertible models only,
regardless of engine. (but the it was a new design and l
the last # was 110Mph)

the 145 MPh used same as 1989 (the last # 140MPH)

Psycho_91Camaro

Would any negative affect happend if I replace my stock 110 cluster


with this




If I do a switch will everything still work properly?

okfoz

It should work fine. For Firebirds its pretty much plug and play. You can usually remove the Odometer from your old unit and install it in the 145 to keep it all legal too

John

aaron7

iTrader: (7)

Wrong. All 88's with the TPI and 16" rims, yes. My 1988 Iroc had the 15" wheels stock and the 110 speedo.

Bandit400

wow, this is rather complicated. I wonder now if there was a set criteria?
Maybe the TPI cars that were red, and built on odd days of even years got the 145mph speedo so long as they had 16 inch wheels. Even day cars could get it regardless of wheels, tranny, or axle ratio as long as there was no holiday that month.

redliterunner

Bandit's on to something, boys.

Bill Speed

I did get a Camaro TPI shot to edit so we should see that soon as well, I did see the 145 designated in the shot which I was not privy to before, being I've only seen a handful of F cars up close hehe
Anyway, that is interesting to note
Bill

okfoz

Actually as of yet no one has been able to discredit the information that I mentioned, so whats the on-going problem?

John

Ant

Here are my pics out of my 89 Iorc with L98 pics. Thanks Bill

aaron7

iTrader: (7)

er... you're missing something

Ant

Heh, lets just say I know fore sure my iroc can do over 145!

FocusGhia

Wrong.

My 88 IROC 305 TPI Auto with 2.72 axle and 16" IROC rims has a 115mph speedo.
And it's 100% factory original.


What will sway a lot of these arguments trying to find the exact reasons is the fact that many cars are not stock.
To contribute to this you need to be sure your car is stock.

aaron7

iTrader: (7)

MY car was entirely stock...

CHEVY_EATER

My friends 90 IROC L98 has a 110...

okfoz

THen its probably a 305... Or someone has switched the IP.

John

jagevileye21

iTrader: (3)

86' Z28 TPI 305

85 mph speedo. My car can do well over 85mph. I read an article that stated in the early 80s that the speedo was used for insurance purposes.

CHEVY_EATER

He is the 2nd owner, car is an original L98 for sure. He has had it since early 90's and the car was 100% stock. I always thought it was odd it though. I have not checked the RPO codes on it but I will one of these nights. The motor/tranny is out...we are doing Vortec heads, HSR, etc..etc..