IRS update

Topic: IRS update (Read 3278 times) previous topic - next topic

Reply #15 – March 28, 2007, 12:23:41 PM

Quote from: 1BadBird;136896

gumby, the springs I used are AFCO springs. I bought them from a "roundy round" shop. I almost bought 800 #ers but thought that they might be a tad too much.

Chuck: how's those mounts coming?? No rush :D

Depending on what you're using up front, the 800# springs in the rear should be fine.

I haven't had a chance to finish up the upper part of the mounts yet....working on it though

IRS update

Reply #16 – March 28, 2007, 04:39:08 PM

ah, more good spring info! i love spring info. are they jus standard stock car springs?
good to know ive got more options w/o having to decipher aftermarket sn95 drop spring ---> fox bird ride heights if i dont like the 750# rate on these 00R springs ive got, or if they dont balance well with my 400# front c/o's.

IRS update

Reply #17 – March 28, 2007, 05:40:50 PM

The wheel rate for a Cobra IRS spring is 33% of the actual spring rate in the stock location.

If you're using coil-overs, the wheel rate is 50% of the actual rate.

So those 750# stock-location springs are 247# at the wheel (800#'s are 264#)

Your front 400# coil overs are 360# at the wheel and the same as 1440# springs in the stock location.

IRS update

Reply #18 – March 28, 2007, 07:15:23 PM

33%, eh? good to know. i knew the liked ALOT of spring and understand why with the location of the spring on the arm, but i hadnt come across a figure in any of my readin yet.

i knew the front c/o was roughly 90%.

IRS update

Reply #19 – March 28, 2007, 07:17:17 PM

33%, eh? good to know.
i knew the IRS likes ALOT of spring, and i understand why with the location of the spring on the arm, but i hadnt come across an actual figure in any of my reading yet.

IRS update

Reply #20 – March 28, 2007, 08:51:22 PM

went and did some searchin on the almighty CC.com. i found it stated in a couple places that the rear IRS rate should be near 5% less than the front rate for good chassis frequency.

for now my car will go together as is, but in order to get to 5%, im gonna need to either raise the rear rate(1050-1100), or drop the front(275-300). guess ill know after i get it on the road.

IRS update

Reply #21 – March 29, 2007, 08:16:24 AM

Chuck, that's some good info to know about the spring rates. I choose the springs I have by going from MM's spring rate for their sport spring rate, i went with the middle rate. The next one was listed as a Race spring. I too will see how the car sits and rides, of course after I do get the thing running.
Take your time Chuck, not in a hurry to put the engine in yet.

gumby, have you thought about checking the 05'+ shocks to see if they have the rebound /compression lengths that would work with our cars?? I had heard that they would fit but haven't checked it out myself yet.

IRS update

Reply #22 – March 29, 2007, 12:59:24 PM

Cool :D

IRS update

Reply #23 – March 29, 2007, 04:07:44 PM

i havent considered s197 shocks at all. i dont think the lower eye bolt hole is big enough for the stock IRS shock bolt.
plus ive got these 04 cobra shocks and struts sittin here :evilgrin:

IRS update

Reply #24 – March 30, 2007, 08:00:29 AM

I need to get some shocks so let me know how those 04's fit, ok? Oncw my wife finishes her Nursing school in May, look out parts suppliers!

Who knows, maybe I'll get the beast going by next spring. :D