Irs?

[Phx99Cobra]

Im new to irs and was wondering what i should have done or add to help my lauch and tire shake. Keeping in mind the cost factor

[BurnTire]

Im new to irs and was wondering what i should have done or add to help my lauch and tire shake. Keeping in mind the cost factor

Drag Radials will get rid of a bunch on the street.

At tire like ET Streets or Slicks with a flexible sidewall will eliminate hop at the track

[Phx99Cobra]

Thx. Will i have to replace the half shafts as i heard most people do. I plan on getting 4:30 gears. What gears is everybody running in their cobras

[BurnTire]

Thx. Will i have to replace the half shafts as i heard most people do. I plan on getting 4:30 gears. What gears is everybody running in their cobras

Read this before your replace the half shafts to LVL 5's.

http://www.highperformancestangs.com/forums/showthread.php?t=2514
http://www.highperformancestangs.com/forums/showthread.php?t=2713


I have the stockers back on and have a pile of low 11 and high 10 second timeslips.

Wheel hop kills the shafts.

[Phx99Cobra]

The stockers have held up with the slicks? Have you or are you going solid?

[BurnTire]

The stockers have held up with the slicks? Have you or are you going solid?

Yes they have held up. I may go Solid, but not time soon.

[Phx99Cobra]

I believe the 03 shaft are different than my stock 99 shafts. If so should i at least upgrade to those stock shaft?

[BurnTire]

I believe the 03 shaft are different than my stock 99 shafts. If so should i at least upgrade to those stock shaft?

Yea the 03/04 are stronger.
I am taking a break from mods for a while. I probably will do the solid next fall. Or I may just run the stockers until they break.

[Phx99Cobra]

Thanks for the help with my desicions. It almost sounds like it may be more cost effective to go solid

[99_venom]

Thanks for the help with my desicions. It almost sounds like it may be more cost effective to go solid

The 99 Cobra IRS has 28 spline shafts, the 01/03/04 are 31 spline. I have a set of raxles in mine to work with the 28 spline IRS.

However if you plan on doing gears then just jump up to a 31 spline carrier when you do the gears and then use the 03/04 shafts. I am also running the Detroit True-Trak in my 99 IRS and I love it. Be careful on the stock 99 shafts with slicks or ET Streets, the outer spline is where these break...then the wheel gets a little crooked, not good if you are moving fast when it breaks. However most of them break right at the line.

[5.0Stanger]

So, the stock IRS will take DOT slicks, but not full slicks? If so, I was thinking about getting a pair of 26" DOTs. I figure that I can start with the 26" size but not sure about wheel size will clear the rear brakes. Honestly, this is the first time I've bothered to research this, feeling that I still need to change the IRS subframe and control arm bushings. I already have the diff bushings done (much reduced wheelhop).

[BurnTire]

So, the stock IRS will take DOT slicks, but not full slicks? If so, I was thinking about getting a pair of 26" DOTs. I figure that I can start with the 26" size but not sure about wheel size will clear the rear brakes. Honestly, this is the first time I've bothered to research this, feeling that I still need to change the IRS subframe and control arm bushings. I already have the diff bushings done (much reduced wheelhop).

I am running full slicks on my IRS. All of my bushings are stock.

If you don't have a billet flow IRS brace get one or you will have an IRS that looks like this.

http://www.highperformancestangs.com/gallery/data/521/irs_fail.jpg

The cure.

http://www.highperformancestangs.com/gallery/data/521/irs_brace.jpg




You will need a 16" or 17" rim.

MT ET streets 26 X 11.5 x 16 or 26 x 11.5 x 17 (these can go on stock rims)

The 16" will give better traction due to more sidewall.

Diamond racing wheels makes some affordable rims for the 16's.

http://www.diamondracingwheels.com/AvengerSeries.htm

If you choose the diamond just call them and tell them you have an IRS cobra and they will send you the correct backspacing.

[5.0Stanger]

Thanks for the info. The only mods to the IRS I've done are the MM aluminum diff bushings and the Billetflow brace. I'll check on the wheels.