Recalibrate speedometer new 390 gear
Thread Starter
Safety Car
Joined: Dec 2009
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From: Birmingham Al
Recalibrate speedometer new 390 gear
I just installed a 390 rear-gear in my 96 6-speed .the speedomeator is off ,how do i fix ??. I'n in houston anybody know a shop were i can take it ,i love the chang don't have a clue on how to fix it...thanks
Team Owner
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If it can't be done in the PCM then it would require a drive and driven gear replacement in the transmission using these parts:
http://www.zr1specialist.com/HAT%20W...on%20Gears.htm
I'd call Corey here and ask:
http://www.hendersonperformance.com/
I thought you were closer but it's a bit of a haul.
Team Owner
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Here's some guys that are in your "neighborhood" and seem well thought of:
http://www.gforce-tx.com/contact
Thread Starter
Safety Car
Joined: Dec 2009
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From: Birmingham Al
Thanks ,I found this place called United Speedomenter in Houston 713-690-1230 .they have a box they put on the vett ,they put the vet on a dyano and adjust the box to the speed and it sets your speed to read right ..One thing about the box you can change it to anything you have ,so if you change the rear gear you just reset the box.One thing i like about it is no parts come off go back Etc. @ $325.00 a little high but easy to do .I am thinking about going that way..The trans gear looks cheaper but a little more work than a little black box..Something to think about.....Thanks for your input.. Lot's good info...
Team Owner
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Thanks ,I found this place called United Speedomenter in Houston 713-690-1230 .they have a box they put on the vett ,they put the vet on a dyano and adjust the box to the speed and it sets your speed to read right ..One thing about the box you can change it to anything you have ,so if you change the rear gear you just reset the box.One thing i like about it is no parts come off go back Etc. @ $325.00 a little high but easy to do .I am thinking about going that way..The trans gear looks cheaper but a little more work than a little black box..Something to think about.....Thanks for your input.. Lot's good info...
Thread Starter
Safety Car
Joined: Dec 2009
Posts: 4,363
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From: Birmingham Al
That would be good if it can be and I was inclined to feel that it could be BUT I thought I'd put the "worst case" out there rather than create maybe some "false optimism"! The phone call to Corey would be the easiest call.
Here's some guys that are in your "neighborhood" and seem well thought of:
http://www.gforce-tx.com/contact
Here's some guys that are in your "neighborhood" and seem well thought of:
http://www.gforce-tx.com/contact
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Thread Starter
Safety Car
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From: Birmingham Al
G-Force said no C-4s .O-Well..Corney turned me on the United Speedomenter in Houston...An Hr.install $325.00 on my way..Sound like a plain...A pcm change sounds easy but to find somebody to work on the C-4 not so easy..I just find it hard to get anybody who will work on a C-4...
Team Owner
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G-Force said no C-4s .O-Well..Corney turned me on the United Speedomenter in Houston...An Hr.install $325.00 on my way..Sound like a plain...A pcm change sounds easy but to find somebody to work on the C-4 not so easy..I just find it hard to get anybody who will work on a C-4...
Thread Starter
Safety Car
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From: Birmingham Al
I check around see if I can find somebody who knows about the PCM change. It's hard to find anybody to work on the C-4s . I check around ?? That would be a easy way to go forsure...
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The other thing to take into consideration is that if there's not a change by axle ratio then the PCM might accept a tire dimension change to reflect the correction also. I've never done anything in a C4 (OBD2) PCM but I would think most of the tuning software out there could do it by axle ratio and the correct tire dimensions. I guess you get to tell us.
I would think the GS guys could tell us.
Last edited by WVZR-1; Feb 14, 2013 at 10:50 AM.
Thread Starter
Safety Car
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From: Birmingham Al
I don't think you need to mention C4 in the initial conversation. Just mention you've changed the rear gears and you would like the PCM in an OBD2 car changed to calibrate the speedometer correctly. You might ask United if they were going to use a Digital Ratio Adapter or if the "BOX" they were referring to is maybe their reference to the device they use to correct the speedometer in the PCM. You just can't ever tell.
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PM - 96GS#007 (Jim) and ask him or if you're familiar with any of the GS users here.
Here's an old post by Jim:
Here's an old post by Jim:
You can correct the speedo two ways: Programming or by changing the plastic gears. Here's why people don't change the gears....of all the gear combinations that GM has available, none of them work with the 4.10s. With all of them the speedo will be off. Years ago, a couple aftermarket suppliers made/offered the custom VSS gear that was needed (LPE was one of them for instance). However the gear was $80...if it was still available I bet it would be over $100 today.
So there you have it. If you can find the aftermarket VSS gear and want to pay for it, you can swap the VSS gear. Programming is the quickest and easiest.
So there you have it. If you can find the aftermarket VSS gear and want to pay for it, you can swap the VSS gear. Programming is the quickest and easiest.
Last edited by WVZR-1; Feb 14, 2013 at 11:06 AM.
Thread Starter
Safety Car
Joined: Dec 2009
Posts: 4,363
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From: Birmingham Al
I don't think you need to mention C4 in the initial conversation. Just mention you've changed the rear gears and you would like the PCM in an OBD2 car changed to calibrate the speedometer correctly. You might ask United if they were going to use a Digital Ratio Adapter or if the "BOX" they were referring to is maybe their reference to the device they use to correct the speedometer in the PCM. You just can't ever tell.
The other thing to take into consideration is that if there's not a change by axle ratio then the PCM might accept a tire dimension change to reflect the correction also. I've never done anything in a C4 (OBD2) PCM but I would think most of the tuning software out there could do it by axle ratio and the correct tire dimensions. I guess you get to tell us.
I would think the GS guys could tell us.
The other thing to take into consideration is that if there's not a change by axle ratio then the PCM might accept a tire dimension change to reflect the correction also. I've never done anything in a C4 (OBD2) PCM but I would think most of the tuning software out there could do it by axle ratio and the correct tire dimensions. I guess you get to tell us.
I would think the GS guys could tell us.
Race Director
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From: Slidell Louisiana
Google Fastchips or his name and LT1 I've used a couple different tuners before going to Ed back in 2006, great tuner great customer service. He still answers my calls and helps me out and its been more than 6 years since he recieved my money.
Mike
Thread Starter
Safety Car
Joined: Dec 2009
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From: Birmingham Al
He's a tuner, with old school business ethics.
Google Fastchips or his name and LT1 I've used a couple different tuners before going to Ed back in 2006, great tuner great customer service. He still answers my calls and helps me out and its been more than 6 years since he recieved my money.
Mike
Google Fastchips or his name and LT1 I've used a couple different tuners before going to Ed back in 2006, great tuner great customer service. He still answers my calls and helps me out and its been more than 6 years since he recieved my money.
Mike
Thread Starter
Safety Car
Joined: Dec 2009
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From: Birmingham Al
Up DATE : ADVANCED RACING DYNAMICS in houston fixed me up ,pluged in there PC about 15 Min. later and $75.00 bucks done deal.. Checked it with my GPS right on....Thanks for all your help..... That 390 rear is WOW... .Now I got to keep a eye on the Tach jump to 7,000 in a heart beat...the old motor won't take much or that ..Me eather..Thanks Guys...