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Did the 1985 GT come with a front lit 120 Mph Speedo? by Sidecar 2M6 SE
Started on: 06-02-2010 04:18 AM
Replies: 21
Last post by: Carcenomy on 06-06-2010 09:24 PM
Sidecar 2M6 SE
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Report this Post06-02-2010 04:18 AM Click Here to See the Profile for Sidecar 2M6 SESend a Private Message to Sidecar 2M6 SEDirect Link to This Post
I know that the 86 GT and some of the 86 2M6 SEs came with a back lit 120 Mph speedo. I know that all of the 85 2M6 SEs came with a front lit 85 Mph speedo. Did the 85 GT come with a front lit 120Mph speedo? If so, does anybody know the part number for it and better yet does anybody know where I can get a 120 Mph front lit speedo for the 85? I have scanned the P22 book and can not find any part numbers for the 85 speedo at all. Any help with this would be greatly appreciated
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Report this Post06-02-2010 04:45 AM Click Here to See the Profile for AustralianClick Here to visit Australian's HomePageClick Here to Email AustralianSend a Private Message to AustralianDirect Link to This Post
You can get better speedometers that that for the fiero i have seen 200 mile hour gauges for the fiero. A V6 fiero will go off the clock in 4th so i am sure it you would need better to measure the top speed of a stock fiero.
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TXGOOD
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Report this Post06-02-2010 07:14 AM Click Here to See the Profile for TXGOODClick Here to visit TXGOOD's HomePageSend a Private Message to TXGOODDirect Link to This Post
My 85 GT had the 85mph speedo.
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Carcenomy
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Report this Post06-02-2010 07:35 AM Click Here to See the Profile for CarcenomyClick Here to visit Carcenomy's HomePageSend a Private Message to CarcenomyDirect Link to This Post
 
quote
Originally posted by Australian:

You can get better speedometers that that for the fiero i have seen 200 mile hour gauges for the fiero. A V6 fiero will go off the clock in 4th so i am sure it you would need better to measure the top speed of a stock fiero.


Unless it's an auto - it runs out of gears before it runs out of speedo

All the '85 GTs I've seen have had the 85MPH speedo. There might be exceptions though... I can't imagine they'd have anything different to the standard 120MPH part though.

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skuzzbomer
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Report this Post06-02-2010 07:52 AM Click Here to See the Profile for skuzzbomerSend a Private Message to skuzzbomerDirect Link to This Post
As far as I know, all early GTs had the 85mph speedo... Mine does - and every other one I've come across had the 85mph as well.

The 120mph speedo was first available on V6 SEs and GTs starting in 86. If you come across an older model with a different gauge, its been swapped or outright replaced at some point.
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Blacktree
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Report this Post06-02-2010 09:41 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeDirect Link to This Post
A friend's choptop is based on an '85 GT. It has the front-lit 85MPH speedo, and the oil pressure gauge in the bottom of the tach. I don't think I've seen any other year GT with the oil pressure gauge in the bottom of the V6 tach (it's normally in the aux gauge set).
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winger1955
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Report this Post06-02-2010 10:49 AM Click Here to See the Profile for winger1955Click Here to Email winger1955Send a Private Message to winger1955Direct Link to This Post
look for one from an 87-88 gt. they will plug and play. i have an 85gt with a front lit 120mph cluster from an 88gt. also you can find an 87-88 coupe 85mph FRONT LIT cluster,and use that. an 85gt uses a BACKLIT unit that are very heard to see and read at night. as long as they are all 2.8 v6 clusters, they should interchange.
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Synthesis
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Report this Post06-02-2010 10:52 AM Click Here to See the Profile for SynthesisSend a Private Message to SynthesisDirect Link to This Post
My 1986 SE model came with the 85MPH Backlit...

Was the 86 2M6 different in that it came with the 120? I thought only the GTs came with the 120 in 86.
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pontiackid86
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Report this Post06-02-2010 11:14 AM Click Here to See the Profile for pontiackid86Click Here to Email pontiackid86Send a Private Message to pontiackid86Direct Link to This Post
86-88 GT's were the only GT's with a 120mph
86 SE's had an 85MPH
all 4 cylinder's had 85mph
87SE had a 120MPH
formula has a 120mph
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dobey
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Report this Post06-02-2010 01:10 PM Click Here to See the Profile for dobeySend a Private Message to dobeyDirect Link to This Post
 
quote
Originally posted by Australian:

You can get better speedometers that that for the fiero i have seen 200 mile hour gauges for the fiero. A V6 fiero will go off the clock in 4th so i am sure it you would need better to measure the top speed of a stock fiero.


I'm pretty sure those so called "200 mph" speedos are actually just custom face plates, and either read wrong, or require changing the speed sensor gear in the trans. I've seen some where the faceplates were printed with the kph speeds, but said 'MPH" instead. With the stock speed sensor setup, this will of course actually read kph, and would require the gear swap to read as mph.
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pmbrunelle
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Report this Post06-02-2010 01:33 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleDirect Link to This Post
You won't be able to get a gear that's ~1.6 times the diameter of the original. To calibrate the speedo differently for different faces, or even tire sizes, the easiest is to play around with key resistor/capacitor/crystal values.

It's an ancient analog design, friendly to the DIY-er.

The Canadian Fieros came with 140 km/h, or 200 km/h speedos as far as I know.

[This message has been edited by pmbrunelle (edited 06-02-2010).]

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dobey
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Report this Post06-02-2010 02:03 PM Click Here to See the Profile for dobeySend a Private Message to dobeyDirect Link to This Post
 
quote
Originally posted by pmbrunelle:
You won't be able to get a gear that's ~1.6 times the diameter of the original. To calibrate the speedo differently for different faces, or even tire sizes, the easiest is to play around with key resistor/capacitor/crystal values.


Well, the best option is to change to the 7730 ECM and use it's output for the speedo, changing the internal mapping table for speed, if necessary.
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hyperv6
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Report this Post06-02-2010 05:32 PM Click Here to See the Profile for hyperv6Send a Private Message to hyperv6Direct Link to This Post
 
quote
Originally posted by dobey:


I'm pretty sure those so called "200 mph" speedos are actually just custom face plates, and either read wrong, or require changing the speed sensor gear in the trans. I've seen some where the faceplates were printed with the kph speeds, but said 'MPH" instead. With the stock speed sensor setup, this will of course actually read kph, and would require the gear swap to read as mph.


I have one of the 200 MPH conversions. It is a face plate that lights up with the front lit light.

To convert it I had to take it appart and soder a new Capacitor or Diode to the board. I don't remember what one it was as I did it about 20 years ago. It was what ever that came in the kit. The speedo works and will read 200 MPH if you can chain the Fiero to a Veyron bumper.

[This message has been edited by hyperv6 (edited 06-02-2010).]

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dobey
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Report this Post06-02-2010 08:14 PM Click Here to See the Profile for dobeySend a Private Message to dobeyDirect Link to This Post
 
quote
Originally posted by hyperv6:
I have one of the 200 MPH conversions. It is a face plate that lights up with the front lit light.

To convert it I had to take it appart and soder a new Capacitor or Diode to the board.


Yes, it was probably a resistor. Luckily the 80s electrics are large enough that it's not too hard to get something soldered in without totally screwing everything up, unlike the electronics of the modern age.
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Rck152
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Report this Post06-02-2010 08:33 PM Click Here to See the Profile for Rck152Click Here to Email Rck152Send a Private Message to Rck152Direct Link to This Post
My 85 gt came with an 85mph back lit now runs a 120mph back lit.{thanks to Mosh-man} And with replacement of a few 194 bulbs shows up great at night.

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hyperv6
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Report this Post06-02-2010 10:31 PM Click Here to See the Profile for hyperv6Send a Private Message to hyperv6Direct Link to This Post
 
quote
Originally posted by dobey:


Yes, it was probably a resistor. Luckily the 80s electrics are large enough that it's not too hard to get something soldered in without totally screwing everything up, unlike the electronics of the modern age.


Resistor I think that is what it was. I had to use a heat sink and it was not hard to do at all.

I have a Canadian 87 GT dash where the MPG goes to 120 MPH and the larger numbers go to 200 KPH if I recall correctly. I have had it in storage for a while. I also have a 120 MPH American too.

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Report this Post06-02-2010 11:39 PM Click Here to See the Profile for jscott1Send a Private Message to jscott1Direct Link to This Post
 
quote
Originally posted by hyperv6:


Resistor I think that is what it was. I had to use a heat sink and it was not hard to do at all.




I bet it's not calibrated worth a crap though. The Fiero Speedometers used a custom chip with the speed calibration hard wired into it. If you change out the crystal you can get multiples of the original speed, but it's never going to be perfect.

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dudewithoutfiero
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Report this Post06-02-2010 11:49 PM Click Here to See the Profile for dudewithoutfieroSend a Private Message to dudewithoutfieroDirect Link to This Post
 
quote
Originally posted by pontiackid86:

86-88 GT's were the only GT's with a 120mph
86 SE's had an 85MPH
all 4 cylinder's had 85mph
87SE had a 120MPH
formula has a 120mph


not all of the 86 se's had 85 mph, later production ones got the 120 mph. mine is an early one and it did have a 85 mph. if some one wants it they can have it free just pay shipping
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Sidecar 2M6 SE
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Report this Post06-03-2010 06:04 AM Click Here to See the Profile for Sidecar 2M6 SESend a Private Message to Sidecar 2M6 SEDirect Link to This Post
 
quote
Originally posted by dudewithoutfiero:


not all of the 86 se's had 85 mph, later production ones got the 120 mph. mine is an early one and it did have a 85 mph. if some one wants it they can have it free just pay shipping


Thanks for all the posts and suggestions. The above post is correct. I have a stock 86 2M6 SE with the 120 Mph speedo from the factory. I have a stock 85 2M6 SE with the 85 Mph speedo from factory.

The 86 speedo is back lit. ie the dash lights shine through it. The 85 speedo is front lit. ie the dash lights reflect off of the red paint on the inside of the cluster housing and this lights up only the face of the speedo. The tach is front lit the same way as the speedo is, in the 85. I guess if I want to put a 120 Mph speedo in the 85 it will not match the look of the 85 tach and if I was to use the tach from a later year to match the look of the 120 speedo. I would lose my oil pressure gauge as mine is in the bottom of the tach because it is an 85. The 1985 2M6 SE didn`t have the aux gauge cluster in the center above the vents.
Oh well, I was hoping to keep it correct to the 85 year for looks and not lose the oil pressure gauge. I guess I am stuck with the 85 Mph speedo that is in it. Thanks again everybody.

[This message has been edited by Sidecar 2M6 SE (edited 06-03-2010).]

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hyperv6
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Report this Post06-03-2010 06:53 AM Click Here to See the Profile for hyperv6Send a Private Message to hyperv6Direct Link to This Post
 
quote
Originally posted by jscott1:


I bet it's not calibrated worth a crap though. The Fiero Speedometers used a custom chip with the speed calibration hard wired into it. If you change out the crystal you can get multiples of the original speed, but it's never going to be perfect.


There really are few speedo's that are that accurate.

As tested by my buddy who was a state park ranger on his radar in his cruiser I average 2-3 MPH off up to 70 MPH
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Report this Post06-03-2010 10:47 PM Click Here to See the Profile for jscott1Send a Private Message to jscott1Direct Link to This Post
 
quote
Originally posted by Sidecar 2M6 SE:


The 86 speedo is back lit. ie the dash lights shine through it. The 85 speedo is front lit. ie the dash lights reflect off of the red paint on the inside of the cluster housing and this lights up only the face of the speedo. The tach is front lit the same way as the speedo is, in the 85. I guess if I want to put a 120 Mph speedo in the 85 it will not match the look of the 85 tach and if I was to use the tach from a later year to match the look of the 120 speedo. I would lose my oil pressure gauge as mine is in the bottom of the tach because it is an 85. The 1985 2M6 SE didn`t have the aux gauge cluster in the center above the vents.
Oh well, I was hoping to keep it correct to the 85 year for looks and not lose the oil pressure gauge. I guess I am stuck with the 85 Mph speedo that is in it. Thanks again everybody.



This is not entirely correct. Even though the '85 speedometer is front lit the GT version has the same look and feel as the 86 back lit cluster. Although the lighting would be different between the 120 mph speedo and the '85 tach from a distance it would be a close match.

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Carcenomy
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Report this Post06-06-2010 09:24 PM Click Here to See the Profile for CarcenomyClick Here to visit Carcenomy's HomePageSend a Private Message to CarcenomyDirect Link to This Post
They'd look different though jscott1 - they changed the fonts between the years. The 120s have that more square and decidedly badass 80s type face, the early 85s use the plain type that looks kinda like Arial.
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