Upgrading a 1999 cobra..

[cobrasvtcoupe25]

Easy take home final from SJSU. The class is Communication Writing shop. My last english class I'm going to have to take for my Accounting degree.

I know it may be a bit vague, but my teacher will have to be able to understand it a little bit...

I thought you guys might enjoy this:SNSign:


THREE IMPORTANT TRUTHS ABOUT UPGRADING A 1999 FORD MUSTANG SVT COBRA.

1999 Ford Mustang SVT Cobra needs a better exhaust in order to breath.
The 1999 Cobra came out of the factory with very restrictive mufflers on the cat-back exhaust system for the 4.6 DOHC Engine. Ford even admitted that the mufflers were very restrictive on the 1999 cobra. It’s very common to find these 1999 Cobra’s with an exhaust system installed or welded-in mufflers. Putting in weld-in mufflers or an exhaust system gives the cobra about an additional 15hp. Not only will it provide additional horsepower, but it also improves the sound of the Cobra by giving it a more aggressive and throatier exhaust note. To help the exhaust on the 1999 Cobra even more owners change the classic H-pipe to an X-pipe. The H-pipe and X-pipe are different ways of how the exhaust leaves the catalytic converters on the Cobra. An X-pipe has been proven to provide a better flow over the stock restrictive H-pipe. The H-pipe gives the Cobra a popping bubbling sound, where an X-pipe gives the Cobra a more flowing exhaust note by reducing backpressure from the Cat-back exhaust system.

1999 Ford Mustang SVT Cobra IRS suspension comes sloppy from the factory.
In 1999 Ford Motor Company introduced the Independent Rear Suspension (IRS) into mustangs for the first time. The only mustang that comes with an IRS is the cobra. It has its pro’s with improved cornering and cons of wheel hop off the line. The IRS came a little sloppy from the Ford Motor Company, but can easily be upgraded. The cobra needs a pair of subframe connectors to delete the uni-body in order to have one solid ride. Subframe connectors improve cornering over stock and remove a lot of the wheel hop problem. The next important thing to upgrading the IRS is replacing all of the rubber bushings to stronger urethane bushings. Replacing the bushings in an IRS will improve wheel hop, shift feel, and power transfer. By upgrading the IRS the 1999 Cobra is more likely to have fewer problems with wheel hop and IRS breakage.

1999 Ford Mustang SVT Cobra lacks a smaller gear ratio.
Coming from the factory stock with 3.27 gears the 1999 Ford Mustang SVT Cobra is in desperate need of smaller gears. The bigger the gear ratio, the faster the car goes through its gears. The stock 3.27 gears were changed in the 2003 and 2004 cobras to 3.55 gears. First gear in the 1999 Cobra will do 45mph with stock 3.27 gears. This is extremely high due to the fact that someone can almost get around town just in first gear. It’s common to see upgrades from the stock 3.27 gears to a higher gear ratio in the 1999 Cobra, which includes 3.55, 3.73, 3.90, 4.10, 4.30, and 4.56. The 1999 Cobra reacts perfect to the 4.10 gear ratio. Many Cobra owners that have the 4.10 gears said it improved their gas mileage and quarter mile times simultaneously. With faster gears like the 4.10’s in a Cobra it makes the car more enjoyable and fun to drive.

 

[Zax]

4.10 better gas mileage???

 

[svtpower]

yep

He's right.

4.10s will actually improve gas milage AROUND TOWN on cars with piss poor low end torque like 99 Cobras because it puts you in your power band quicker where the engine is more efficient. On the highway they will slightly hurt your gas milage though as your cruize rpms in 5th will be higher.

 

[Zax]

Not in my car case. I get better mileage with the 3.73s. Had 4.10s before, and definitely didnt get better mileage.

 

[cobrasvtcoupe25]

Not in my car case. I get better mileage with the 3.73s. Had 4.10s before, and definitely didnt get better mileage.

It all depends on the driver, were you drive, and how you drive to get their. (fast or slow)

It's better for city, but can be worst for freeway.

I was told from a 2001 cobra owner that 4.10's improved his gas mileage because he did more driving in the city then on the freeway and so do I. Can't wait until I get gears......

In the paper I was just trying to get the point across that any gear ratio upgrade should help out gas mileage compared to the long stock 3.27's. Of course except 4.30's and 4.56's.

What type of driving do you do? do you smash to your destination?

Why did you switch from 4.10's to 3.73's?

O yeah you 99 cobra is clean too....

 

[Zax]

Thanks man, I drive pretty mild most of the time so maybe thats it. The 4:10 were killing me on the highway, and first was nearly useless, lol. In the city I might get 1-2 MPG better with the 3:73 and the Highway maybe 4-5 MPG better. Im going to take some better pics soon. Weather has been bad so, I havent been able to really do much. It has been garage kept through the winters here, and has never seen the salt. I intend to keep it that way. And as for the low end torque I didnt really think 328 lb/ft at the rear wheels was low? TQ peaks at 5150RPM and HP peaks 329 at 5950. Maybe he was talking about stock or something, even though I baselined at 285.5 RWHP and 284.2 RWTQ. But then again maybe I just got one of those freak factory cars. You see where I am going with this, these cars do not have weak low end torque. Lower than the Pushrod motors, but not weak.

 

[Destroyer442]

I'm not all that crazy about the 4.10's in my '99 Cobra. Rowing through the gears way too much. I dont even bother with first gear, I take off in second. The acceleration is impressive though. I would give up a little of that acceleration for some longer gears. 3.73's might be good.

 

[LaserSVT]

Always some discussion on here about gears I still vote for 3.73s, I have them and love them. I get 23-24 MPG average with city and highway driving and can light em up all the way through second gear so more gear seems useless

 

[cobrasvtcoupe25]

I'm not all that crazy about the 4.10's in my '99 Cobra. Rowing through the gears way too much. I dont even bother with first gear, I take off in second. The acceleration is impressive though. I would give up a little of that acceleration for some longer gears. 3.73's might be good.

Did you do any suspension mods???

 

[Destroyer442]

Did you do any suspension mods???

Car is at stock height but it does have some suspension mods. I noticed camber plates and aftermarket shocks but I'll have to check and see what kind.

 

[hvcobra99]

Gear Gears Gears

I have 99 cobra and installed 373 with 18inch wheels 255 front 265 rear 35.s I cant imagine 410 being better for gas and or quarter mile unless you run slicks all day long . Thats just my opinion.

 

[Destroyer442]

I have 99 cobra and installed 373 with 18inch wheels 255 front 265 rear 35.s I cant imagine 410 being better for gas and or quarter mile unless you run slicks all day long . Thats just my opinion.

I can only relate this to my buddies '04 Mach 1 before he had a supercharger on it. With 4.10's he ran faster times in the 1/8th and 1/4mile with higher trap speeds than he did with the stock 3.55 gears. He complained (as do I) that the gears were a PITA for everyday driving. He now has 3.73's and a Vortech supercharger and is happier with those gears.

 

[cobrasvtcoupe25]

I can only relate this to my buddies '04 Mach 1 before he had a supercharger on it. With 4.10's he ran faster times in the 1/8th and 1/4mile with higher trap speeds than he did with the stock 3.55 gears. He complained (as do I) that the gears were a PITA for everyday driving. He now has 3.73's and a Vortech supercharger and is happier with those gears.

With out a supercharger would you go with 4.10'S