Gear question

CobraPower97 · 04-09-2001, 12:27 PM

I bought a 4.10 gear set for my Cobra and was wondering how the car is for the street. How is the rmp range in 5th gear on the highway? I got a good deal on the gears from a friend they are brand new Richmond gears. Anyone use them?

Thanks

97snakedriver · 04-09-2001, 12:45 PM

I have 4.10s. They are fine for the street. For the track I would go with something higher (4.30+), but if you do highway driving 4.10s are probably enough.

RPM at 70 is about 2500. I haven't had any loss in milage.

bark3rd · 04-09-2001, 02:22 PM

Check out the thread titled "is chip needed for 3:73's" for some addtl' info. I have since decided to go for 4:10's myself, they are being installed Wed., I'll let you know how they work out.

------------------
Black 2000 GT,5 spd,17" wheels,mach,leather

T_Bone · 04-09-2001, 05:29 PM

bark3rd, the difference is he is in a Cobra, you have a GT.
I had 3.73's in my 96GT
I have 4.10's in my 97 Cobra. I'll be changing to 4.56's this summer. Here is a link to an RPM/Speed/Gear calculator.
http://www.corral.net/tech/gearcalc.html

------------------
T-Bones 1997 Cobra
Wht/blk, Pro 5.0,FRPP 4.10's, aluminum driveshaft, FRPP throttle body, C&L 80mm MAF, K&N, Steeda U/D pulleys, Steeda timing adjuster, Flowmasters, s/f connectors, FRPP pro springs, BBK caster/cambers.

AutoX281 · 04-09-2001, 07:52 PM

T_Bone: Why does Cobra vs GT make a diff? is it b/c the DOHC can handle the higher rpms better than the SOHC? I don't know much about the cobra engine specs...

------------------
98 GT Conv: K&N, Pro-5.0, MSD wires

CobraPower97 · 04-10-2001, 10:55 AM

So how did the performance improve when you put the 4.10s in? Do you run at the track? What kind of numbers after the gear change?

97snakedriver · 04-10-2001, 02:08 PM

Quote:

Originally posted by AutoX281:
T_Bone: Why does Cobra vs GT make a diff? is it b/c the DOHC can handle the higher rpms better than the SOHC? I don't know much about the cobra engine specs...

Cobras rev higher and make their power and torque higher in the RPM band. You shift a stock Cobra at 7000 RPMs when racing.

04-10-2001, 10:05 PM

T_bone,

I have just recently put 3:73 gears in my mustang. It is also a 1996 gt. Were you able to buy gears for the speedometer, or did you use an electronic speed sensor?
If you used gears what size and where can I get a hold of them?

sean

T_Bone · 04-13-2001, 01:00 AM

69ergt, I used the white 23 tooth speedo gear. I got it from Steeda because Mustangs Unlimited was out of stock. They raped me in shipping charges. Like $8 to ship a little plastic gear the size of your thumb

The gear runs about $20+ s/h.
Good luck!

BTW, my 4.56's are on their way to me, hehe. Can't wait.

[This message has been edited by T_Bone (edited 04-13-2001).]

04-13-2001, 02:03 AM

Anything less than 4.56 on a Cobra is just a waste of hard-earned dollars!!!

Even with a blower, nitrous, or turbo, you can run 4.56's, just get 28" tires.

If you want to know why you should run 4.56 in a Cobra, look at my sig.

Later, Jason

------------------
N/A 1997 Cobra

1/8 mile - 7.83 @ 90.08 MPH
1/4 mile - 12.26 @ 114.02 MPH
1.64 60 ft.

96gtToy · 04-15-2001, 12:09 PM

thanks t_bone. No-one has given me a straight answer about the gear needed for my speedometer.

1996 gt, K&n filter, 373 gears.
sean

T_Bone · 04-15-2001, 12:16 PM

Quote:

Originally posted by 96gtToy:
thanks t_bone. No-one has given me a straight answer about the gear needed for my speedometer

no problem

95GTS · 04-18-2001, 10:20 PM

Just a forewarning fellas, the 23 tooth speedo gear is the one to get the speedo closest (though will still be about 5 mph off after 60 mph), BUT it WILL be chewed up (in the GT). It may take a month or two, depending on how much you drive, but the teeth on the 23 tooth speedometer gear DO NOT mesh with the 8 tooth internal drive gear on the GT T45 trans. IF you use speedo and internal drive gears to correct the speedo you need the 21 tooth (red) speedo gear and the 7 tooth internal drive gear. Only problem is there is no 7 tooth internal drive gear made for the GT. Just for the Cobra. The Cobra has different splines in the center of the internal drive gear than the GT has so you can not use the Cobra internal drive gear. I've been thru this already when I had my 3.73s put in and my transmission rebuilt in my 96 GTS, as some of you probably remember. The ONLY way to get the speedo to read correctly is to use a MECHANICAL speedometer compensator. The new 99-up models use the ELECTRONIC speedometer compensator. I had the 21 tooth in my stang because it was the largest one that would fit and mesh with the 8 tooth internal drive gear. Your speedo will still be off, just not as much as with the 18 tooth (yellow) stock speedo gear. It's the best you can do unless you like particles of plastic speedo gear floating in your tranny fluid and constantly replacing the 23 tooth every few months, or just get the mechanical speedo compensator.

With your Cobra, it already has the 7 tooth internal drive gear so with your 4.10s install the 23 tooth speedometer gear. I believe it does mesh with the 7 tooth. If I'm not mistaken 97snakedriver is running this setup and has not had a problem ( I think it's him, anyways).
------------------
1994 Red SVT Lightning #2019

[This message has been edited by 96GTS (edited 04-18-2001).]

97snakedriver · 04-19-2001, 12:35 AM

Yeah its me. Me and my 23 tooth gear are getting ready to celebrate our 30,000 mile together. The speedo was off by 3 mph@70 and pretty close every where below that.

95GTS · 04-19-2001, 07:37 PM

I thought it was you. But couldn't quite remember.

------------------
1994 Red SVT Lightning #2019

04-09-2001, 12:27 PM	#1
CobraPower97 Registered Member Join Date: Apr 2001 Location: Olrand Hills, IL - USA Posts: 5	Gear question I bought a 4.10 gear set for my Cobra and was wondering how the car is for the street. How is the rmp range in 5th gear on the highway? I got a good deal on the gears from a friend they are brand new Richmond gears. Anyone use them? Thanks

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04-09-2001, 12:45 PM	#2
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	I have 4.10s. They are fine for the street. For the track I would go with something higher (4.30+), but if you do highway driving 4.10s are probably enough. RPM at 70 is about 2500. I haven't had any loss in milage.

04-09-2001, 02:22 PM	#3
bark3rd Registered Member Join Date: Mar 2001 Location: AUSTIN, TX, USA Posts: 91	Check out the thread titled "is chip needed for 3:73's" for some addtl' info. I have since decided to go for 4:10's myself, they are being installed Wed., I'll let you know how they work out. ------------------ Black 2000 GT,5 spd,17" wheels,mach,leather

04-09-2001, 05:29 PM	#4
T_Bone Registered Member Join Date: Jul 2000 Location: Minot AFB, ND Posts: 207	bark3rd, the difference is he is in a Cobra, you have a GT. I had 3.73's in my 96GT I have 4.10's in my 97 Cobra. I'll be changing to 4.56's this summer. Here is a link to an RPM/Speed/Gear calculator. http://www.corral.net/tech/gearcalc.html ------------------ T-Bones 1997 Cobra Wht/blk, Pro 5.0,FRPP 4.10's, aluminum driveshaft, FRPP throttle body, C&L 80mm MAF, K&N, Steeda U/D pulleys, Steeda timing adjuster, Flowmasters, s/f connectors, FRPP pro springs, BBK caster/cambers.

04-09-2001, 07:52 PM	#5
AutoX281 Registered Member Join Date: Mar 2001 Location: San Jose, CA Posts: 27	T_Bone: Why does Cobra vs GT make a diff? is it b/c the DOHC can handle the higher rpms better than the SOHC? I don't know much about the cobra engine specs... ------------------ 98 GT Conv: K&N, Pro-5.0, MSD wires

04-10-2001, 10:55 AM	#6
CobraPower97 Registered Member Join Date: Apr 2001 Location: Olrand Hills, IL - USA Posts: 5	So how did the performance improve when you put the 4.10s in? Do you run at the track? What kind of numbers after the gear change?

04-10-2001, 10:05 PM	#8
69ergt Guest Posts: n/a	T_bone, I have just recently put 3:73 gears in my mustang. It is also a 1996 gt. Were you able to buy gears for the speedometer, or did you use an electronic speed sensor? If you used gears what size and where can I get a hold of them? sean

04-13-2001, 01:00 AM	#9
T_Bone Registered Member Join Date: Jul 2000 Location: Minot AFB, ND Posts: 207	69ergt, I used the white 23 tooth speedo gear. I got it from Steeda because Mustangs Unlimited was out of stock. They raped me in shipping charges. Like $8 to ship a little plastic gear the size of your thumb The gear runs about $20+ s/h. Good luck! BTW, my 4.56's are on their way to me, hehe. Can't wait. [This message has been edited by T_Bone (edited 04-13-2001).]

04-13-2001, 02:03 AM	#10
jmeiers Guest Posts: n/a	Anything less than 4.56 on a Cobra is just a waste of hard-earned dollars!!! Even with a blower, nitrous, or turbo, you can run 4.56's, just get 28" tires. If you want to know why you should run 4.56 in a Cobra, look at my sig. Later, Jason ------------------ N/A 1997 Cobra 1/8 mile - 7.83 @ 90.08 MPH 1/4 mile - 12.26 @ 114.02 MPH 1.64 60 ft.

04-15-2001, 12:09 PM	#11
96gtToy Registered Member Join Date: Apr 2001 Posts: 8	thanks t_bone. No-one has given me a straight answer about the gear needed for my speedometer. 1996 gt, K&n filter, 373 gears. sean

04-18-2001, 10:20 PM	#13
95GTS Git jiggy Join Date: Oct 1999 Location: MO USA Posts: 865	Just a forewarning fellas, the 23 tooth speedo gear is the one to get the speedo closest (though will still be about 5 mph off after 60 mph), BUT it WILL be chewed up (in the GT). It may take a month or two, depending on how much you drive, but the teeth on the 23 tooth speedometer gear DO NOT mesh with the 8 tooth internal drive gear on the GT T45 trans. IF you use speedo and internal drive gears to correct the speedo you need the 21 tooth (red) speedo gear and the 7 tooth internal drive gear. Only problem is there is no 7 tooth internal drive gear made for the GT. Just for the Cobra. The Cobra has different splines in the center of the internal drive gear than the GT has so you can not use the Cobra internal drive gear. I've been thru this already when I had my 3.73s put in and my transmission rebuilt in my 96 GTS, as some of you probably remember. The ONLY way to get the speedo to read correctly is to use a MECHANICAL speedometer compensator. The new 99-up models use the ELECTRONIC speedometer compensator. I had the 21 tooth in my stang because it was the largest one that would fit and mesh with the 8 tooth internal drive gear. Your speedo will still be off, just not as much as with the 18 tooth (yellow) stock speedo gear. It's the best you can do unless you like particles of plastic speedo gear floating in your tranny fluid and constantly replacing the 23 tooth every few months, or just get the mechanical speedo compensator. With your Cobra, it already has the 7 tooth internal drive gear so with your 4.10s install the 23 tooth speedometer gear. I believe it does mesh with the 7 tooth. If I'm not mistaken 97snakedriver is running this setup and has not had a problem ( I think it's him, anyways). ------------------ 1994 Red SVT Lightning #2019 [This message has been edited by 96GTS (edited 04-18-2001).]

04-19-2001, 12:35 AM	#14
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Yeah its me. Me and my 23 tooth gear are getting ready to celebrate our 30,000 mile together. The speedo was off by 3 mph@70 and pretty close every where below that.

04-19-2001, 07:37 PM	#15
95GTS Git jiggy Join Date: Oct 1999 Location: MO USA Posts: 865	I thought it was you. But couldn't quite remember. ------------------ 1994 Red SVT Lightning #2019