IRS Install: Final touches

Everything is in and it fits…what a success!  Final alignment touches are being done.  The last steps are to weigh and measure for the car’s final numbers.  Rob weighed the car and the final weight was 3375 lbs..  That is 48 lbs. heavier than the initial 3327 lbs. it originally weighed in at.


Mustang LX  (w/ torque arm & panhard bar)         3327 lbs.

Mustang LX (with IRS)                                            3375 lbs.

Difference                                                               +48 lbs.

One of the advantages of installing coil-overs, is that we can adjust the height on each spring.  Raising or lowering each corner also transfers weight from front-to-back and side-to-side, just like NASCAR when they add or take away wedge.  This is a bit time consuming…going back and forth adjusting each corner.  It’s first done with sway-bars disconnected, then when re-installed weight gets shifted, so more tweaking is necessary.  You also need to do this driver.  In the end, we got a very good ride height, stance and the best weight balance we thought was capable.

Front Left = 1037 lbs.               Front Right = 929 lbs.

Rear Left = 871 lbs.                   Rear Right = 864 lbs.

Wheel clearance

Wheel clearance

Wheel base remained the same…give or take a few centimeters.  The original wheel base measured was 57″ 7/16.  The after measurement with the IRS is about the same.  It’s hard to get an exact number like before with the SRA, because on a SRA the tires sit flat and a measurement is exact.  On the IRS each tire sits differently, not perfectly flat.  So to get a proper number you have to measure at 2 locations on the tire and get the average.  Anyway, it was close enough to say, that it remained the same.


9 thoughts on “IRS Install: Final touches

  1. Just curious as to what coilover set up you are running from Maximum Motorsports in regards to dampeners and spring rates? I have an 88 Saleen vert that I’m getting ready to order the coil overs for and since our cars are similar I thought the information would be helpful. My car is a street car though and will very rarely see the track.

    1. So I spoke with someone at MM and told them what I wanted…a street car that would see occasional track days. I didn’t want a stiff, unbearable ride. So they recommended their Koni single adjustable dampers with 300lbs. springs coil-over kit. It works great for me on & off the track and when I added an adjustable rear sway bar, it really made a difference on the track.

      1. Are you running coilovers in the rear as well? They recommended Bilstein HDs with 250lb x 12″ x 2.5″ front springs and 425lb x 8″ x 2.25″ rear springs. I’m looking for a good handling street car with good road manners that doesn’t ride like a dump truck. Are you happy with the set up on the street?

  2. Coming from a PHB TA setup, can you give some opinions on how you like the IRS? I’m contemplating IRS vs PHB TA now.

    1. I love the IRS, but I don’t think its worth the money for daily driving or occasional spirited driving. Benefits are really only significant on the track…especially if its set up correctly. Only if you can get an IRS cheap and do all the work yourself, could Price vs Reward be worth it.

      1. I agree on the price standpoint. $1500 for IRS + bushing kit $1000 + install and misc costs $800. At $3300. And exhaust, shocks, springs, and alignment on top of that. But for your setup I think it’s justified. I’d love to see a video by TheSmokingTire guy driving your car.

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