Gears Gears Gears!!!!
 

GEARS GEARS GEARS!!!!, thats all i ever hear on every single page of this forum, so they gotta be good. Ive got a 99 cobra, pretty much stock except for the h-pipe, and im pissed that camaros and trans ams can get me right of the line. My car has good high end but the low end hp sucks!! I want gears cause everybody says that that is the cheapest thing that will actually make a noticible difference. I have a few questions about them since i know nothing about them (sorry). I know that the preferred brand is FRPP, but here are some questions, any help is apreciated:
1)how will they affect the speed of the car, low end, high end, top speed, quarter mile times.
2)3.73's or 4.10's, i do both highway and city but im looking for a good take off to beat camaros and trans ams
3) will they put any excessive wear on the car
4)what do the gears actually do
5) and any other explinations about gears.

thanks, sorry for all the writing but any help is apreciated, im new at this stuff.

The gears you want for your Cobra are 4.10s or 4.30s. Lower ratio (higher numerically) gear sets make it so your wheels rotate less times per engine rotation.

From a technical speaking standpoint, they increase torque multiplication, control engine speed within the powerband better, and they allow you to get into the powerband from a dead stop quicker. The Cobra is a high revving, high horsepower engine. To take advantage of it's high rpm capability, you need to get into the powerband as quickly as possible, and stay in the meat of it as much as possible during a race. Gears allow you get there, and when you shift, they'll keep your rpms up higher. There will be a very significant increase in performance from off the line, all the way through the 1/4 mile. As far as top end is concerned, neither gear should hinder you in speed. Your car will actually top out in 4th gear with stock gearing. With 4.10-4.30 gears and traction, you can expect to drop several tenths in the 1/4.

I will make the suggestion of some good quality springs (to reduce wheelhop), and some better tires like drag radials. The 99 Cobra's IRS is a bit on the dainty side, so the other members will have to advise you on how reliable the stock IRS is with drag radials. I've heard of people blowing them out.

highway driving
 

changing gears will increase your accelleration but decrease top end speed (or raise the rpm to attain a certain speed)

if you do any significant highway driving (daily driver ?), i would go with 3.73s otherwise 4.10s. i have 4.10s and i pull 2400 rpm @ 63 mph. 3.73s should lower that to about 2200.

Don't waste your time on 3.73's for a Cobra. The 32V cars need 4.10s or 4.30s to take advantage of their high-revving powerband.

Re: highway driving
 

Unit brought up a good point on this. When my car had the stock 2.73 gears, 5th gear was useless and my top speed was determined by 4th gear. With my 3.73's I can actually use 5th gear, and although I have not really tried, I suspect that my top speed would remain unchanged.

thanks for the help, ive already got 18X10 inch rims in the back and and looking for the fastest possible take off from stop so it looks like 4.10 gears?? Also, i dont mind being at high rpms in the highway, if im gonna do this mod, i wanna do it right to get the most possible power, i cant afford a supercharger so gears looks like my next mod. Also, does anybody know what gears i currently have in the car( not that it really matters, just wondering). Any other responses to this topic are apreciated, thanks!!!

sorry but does anybody have any suggestions of where to get the gears from, links to websites are helpful. thanks

I think the 99 Cobras had the same gearing as the GT's, 3.27s.

Check out

www.dallasmustang.com

www.lonestarperformance.com <--- (this is where I got my gears from)

www.summitracing.com

if all you want is all out take-off power, get 4.30s.

The 4.30s will not hinder your top speed. Nor would 4.56's. With 4.30's you'll be turning about 2800rpms at 70mph instead of 2000rpms. It will cost you some fuel economy, but only a couple of mpg.

wally6761 would be correct IF the Cobra's (or any other Mustang for that matter) had gear limited top speed. They don't. They have power limited top speed. With a 7000rpm redline, you could still do 180mph in 5th gear with the Cobra having 4.30's. I seriously doubt you'll see it. LOL.

Thanks guys, it looks like im going to go with the 4.30 gears cause if im gonna spend $200 or more, might as well do it right the first time. i want the most bang for my buck and it looks like 4.30 gears are the way to go. Is there anything else i need to know before i do this mod, like anything else i need to change or buy in order to get this done??

Once again, thanks for all the help!!!!!!!!!

QUESTION::
I just read somewhere that the gears will mess with the speedometer, and kick the governor in early, like around 100mph, is this true??? I plan to install this myself with a friend who is a master mechanic, how will we adjust the speedometer, and will my governor kick in early, is there anything we need to know before we do the job?? thanks.

To correct the speedo you need the speedcal the cost about $100.00 you can get them through www.Dallasmustang.com.Does your car still have the irs? If it does it is a lot harded to set up then a 8.8 live axle.Tim

Yes, i still have the irs, thanks for the speedo fix. Do you guys think 4.30's will be too much since i drive the car through michigan winters, this is my only mode of transportation. Ive been hearing 4.30's are too much and that i should go with a 4.10???

Thanks

I would go with the 4.30's. I have a 97 cobra with 4.10's. I sometimes wish I would have installed 4.30's. You should not notice much of a difference in gas milage either, especially in town driving.

Even if you have the stock gear in driving in michigan in a Cobra or any other rear wheel drive sports car will suck. I don't know if I would want to tackle that gear change, even if your friend is a master mechanic. And i'am not dissing your friend. I just know that the power these cars have and the gear your about to put in will put some strain on your rear end. And I would want to know if somthing went wrong I could take it back to the person that did it. And have them deal with the problem. I did all the work with rear end swap, however it's the 8.8 set up. And it was still a pain. There are plenty of shops around us DTS, Paul's High Performance, Alternative Auto, and Detroit Speedworks just to name a few and they all do great work.

And another word of advice get all the neccesary parts to strengthen that IRS, don't be cheap I found out the hard way.

Thanks,

Hey 98snake, how do you like your 4.30's, also, i wont be running slicks and i dont race at the track to often. i do regular driving and im looking for a better take off, are you 4.30's the way to go, or would you recommend 4.10's, also, did you top end get affected in any way and how did you fix your speedo???
thanks

The stock gears put more pressure on the rear end than lower gear ratios. Launching with a lot of power on 3.27's puts way more stress on the metal back there than launching on 4.30's. It does put more pressure on the axles if you can hook though. Both the 98, and the 99+ Cobra's have an 8.8" rear end.

Having a lower ratio will be nice for winter, IMO. My 87GT has 2.73's and they really suck for control in low traction areas. You just have to slip it out so much because when it grabs, you're instantly putting 15mph on the back tires. It causes a lot of spinning. Drive with your head, shift up quick, and you shouldn't have a gear related problem. I would seriously suggest some dedicated snow tires.

Go with the 4.30's if you want a take off gear then you will love them I do. Don''t bother with the 4.10's for the little difference between the two your better of with the 4.30's. I'am not sure on my top end yet because I have'nt installed my speedo gear. Even after that my speedo still won't be dead on because they only make a speedo gear high enough for the 4.10's. As for you all you have to do is get a speedcal to change your's. Good luck.


Will

If you don't plan on going to the track that much then I would go with the 4.10s reason being is with the 4.30s you are going to be spinning alot more.I know I have had both 30s & 56s alot more tire spin no 1st gear it's all spin,but I plan on racing mine in NMRA.Think about this if your spinning your not moving, unless you have tires that can hook that gear.From the 4.30s to the 4.56s rpms went up about 150 to 200 now I am about 3000rpm at 70 in 5th.Tim