Will the stock Bilsteins ('03/'04 Cobra) dampen 1,000 lb./in. front springs (H&R Super Race) properly on the track? Max. Motorsport says OK. What do you think?
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1.000 lb./in. Springs
- Thread starter oxfordman03
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oxfordman03 said:
Surprised Max Motorsport said Ok, they told me 00R Bilsteins were inadequate for my 04 Cobra Vert if I wanted to run coil overs above 400 Lbs., and reccomended Race 3 bilsteins and 500 Lb/In springs. I belive the 500 Lb/in coilover is about equivelant to 1000 Lb/in conventional.
I was running 800 Lb/in Griggs and I will be going to 1000 Lb/in any day now. The H&R's in my past experience were progressive rate (H&R Race), so I never used them.
I did talk to a guy @ Autobahn this last weekend that is running 500 Lb/in coil over springs w/ stock Bilsteins. He says it is ok and that MM told him not to run over 400 Lb/in w/ stock Bilsteins.
The "super race" are rated 950-1050. MM said to start here with stock Bilsteins and they "should" be fine. If they turn out to be inadequate the car will have a tendancy to bounce which would indicate that the spring wants more damping. They (Matt @ MM) reccomended the same coilover set up for me that you mentioned so we know that is right (I don't want the c/o at this time. not sure it's right for me and the $$$) and I think your conversion from coilover to conventional rates is pretty close. Thanks for the input. I'll start here as they said. It's easy enough to swap struts later.
Ok, got my 1000 Lb/In on the other day. I cut 1/2 coil from a 12" spring and ended up with 2-1/2 fingers between the tire and fender. This was running w/o any isolators on a spring that had 6 coils. I estimate that my final spring rate based on what I cut off would be about 1050 LB/In. If I were to do it again I would cut off a little less. I still plan on installing FRPP ball joints, which will lower the car another 1/2 inch, and I will have to install the isolator to bring it back up that 1/2"
Took the car to the track and it seemed to take the corners perhaps better. It definitely did not lean as much as before, it felt much flatter. I also fabricated a rake below my radiator for cooling to replace the factory rake. It did not hit the ground on corners, but it did on moderate braking. So my heavy car still dives down more than it leans and I would not be afraid of trying 1100 or 1200 springs.
On the street they seemed ok, and were very similar to the 800 LB/In Griggs springs I had. I never got the oscillation from poor dampening, but I do get a fore/aft oscillation from time to time on the street. I got it w/ both my old 800 Lb/In and my new 1000 Lb/In springs w/ Cobra-R struts. Mathis once said the front/rear springs should be within 5% of each other so that you don't get that oscillation. But I couldn't imagine 1000 Lb/In springs in the rear and don't hear much about what people do in the rear.
Took the car to the track and it seemed to take the corners perhaps better. It definitely did not lean as much as before, it felt much flatter. I also fabricated a rake below my radiator for cooling to replace the factory rake. It did not hit the ground on corners, but it did on moderate braking. So my heavy car still dives down more than it leans and I would not be afraid of trying 1100 or 1200 springs.
On the street they seemed ok, and were very similar to the 800 LB/In Griggs springs I had. I never got the oscillation from poor dampening, but I do get a fore/aft oscillation from time to time on the street. I got it w/ both my old 800 Lb/In and my new 1000 Lb/In springs w/ Cobra-R struts. Mathis once said the front/rear springs should be within 5% of each other so that you don't get that oscillation. But I couldn't imagine 1000 Lb/In springs in the rear and don't hear much about what people do in the rear.
Good information. My springs go on tomorrow (Monday) and to the track next Sunday. I'll post my results also. I'm still doubting the damping ability of the stock struts but we'll see. Would not that account for your fore/aft oscillation? No one has a 1,000 lb spring for the rear (IRS cars). Don't know why. Maybe too much?
if i remember correctly a 1000lb(1000 x .250 conventional spring equals a 250lb wheel rate. a 400lb(400 x .90) coil over equals about a 360 wheel rate. i would think that the reason they don't have a 1000lb rear spring is
1. not a popular demand
2. most people will just get coil overs once they can custom tune their suspensions
1. not a popular demand
2. most people will just get coil overs once they can custom tune their suspensions
Makes sense.
Springs installed. I expected the car to be nearly unstreetable but it feels very good. After some "spirited" driving, hard braking ect. the car seems to be planted much better, less body roll and nose dive. The stock Bilsteins seem to be fine for these springs. No bounce or oscillation apparent. Track day Sunday will tell me for sure.
Guys can you post some pictures of your cars with the springs (so I can get an idea of ride height) along with information on who's springs your running and where you got them. I'm running Eibach's right now and they are way to soft. I've been trying to find the spring rates of the Eibach's but haven't had any luck. They don't feel much heavier than say 650 #'s. My car leans and dives waaaaayyyyyyy to much. Also after installing the full IRS bushing kit my car started to show signs of not enough dampning. I haven't done anything with the shocks and struts yet as I'm waiting to find the right spring combo. I have been looking at the Steeda race springs up front, but not sure of the rear spring rate yet. I'm thinking about the Steeda race springs up front and the Eibach's in the back for starters.
Darin
Darin
the eibachs are about 500-600 up front and 700- 800 rear. (eibach does not disclose there rates cause most people would not buy softer springs for the front, that is if you have an 03/04 cobra) can't remember exactly but my sponsor was able to get me the specs. eibach uses these rates to help improve the under steer problem the cobra's have. if you use the higher rate in front your car will plow worse then stock even though it will not sway or brake dive as much. i went with the h&r race fronts and the eibach rears.
racebronco2 said:
I actually had a go round with Eibach when I bought these springs and put them in. They list a certain amount of drop when using these springs. The rears were close but the fronts weren't. On further checking I found out they list the same springs for the 99-04 Cobra and the same drop. Well the 03-04 Cobras are a fair amount heavier in the nose than tha 99-01. Eibach didn't want to come out with an 03-04 specific set so they still sell the one size fits all. The springs aren't bad for street driving for someone that wants a pretty slammed look. Problem is the rates aren't nearly high enough for track use on the 03-04 cars.
How does your car handle with your spring combination? What rate are your front springs?
Darin
I would go w/ specific rate and Steeda is not. The only specific rate I know of is:
OEM Cobra Springs
FRPP Springs
Eibach Cobra-R Springs (Front Discontinued)
Kenny Brown
Griggs
The Griggs are manufactured by bluecoilspring.com. Select front unpainted springs, 5"OD, Free Length 12". They are $53.00/each direct from the manufacturer or $72.50 from Griggs. When you order them from Griggs they will be painted blue, but drop shipped from bluecoilspring. The above is for the front.
Rear springs are 5-1/2" OD for our IRS Cobra's. The length I am not sure, but appears to be the same as the front.
$53.00 for springs is even cheaper than the coilover springs.
OEM Cobra Springs
FRPP Springs
Eibach Cobra-R Springs (Front Discontinued)
Kenny Brown
Griggs
The Griggs are manufactured by bluecoilspring.com. Select front unpainted springs, 5"OD, Free Length 12". They are $53.00/each direct from the manufacturer or $72.50 from Griggs. When you order them from Griggs they will be painted blue, but drop shipped from bluecoilspring. The above is for the front.
Rear springs are 5-1/2" OD for our IRS Cobra's. The length I am not sure, but appears to be the same as the front.
$53.00 for springs is even cheaper than the coilover springs.
To continue getting sidetracked, I believe the OOr has 800 lb front springs and 750 in the rear. These and revalved Bilsteins are too soft for the track, I'm learning.
On the topic, I don't think you could expect stock struts to dampen a 600 lb. spring correctly and a 1000 lb. spring with the same valving. Sure, you could drive it but I can't imagine there wouldn't be room for improvement with more aggressive strut valving to control that spring.
For spring rates, I found this:
http://www.miracerros.com/mustang/springs_calcs.htm
On the topic, I don't think you could expect stock struts to dampen a 600 lb. spring correctly and a 1000 lb. spring with the same valving. Sure, you could drive it but I can't imagine there wouldn't be room for improvement with more aggressive strut valving to control that spring.
For spring rates, I found this:
http://www.miracerros.com/mustang/springs_calcs.htm
Without going the coilover route, H&R super race (950-1050lbs) front and H&R race (770lbs) rear, were the heaviest conventional springs I could find.(These from Max Motorsports). I talked with Steeda who had a similar set up with a 1,000lb front from their race group and a '00 Cobra R rear. I just removed my Kenny Brown Club Sport Springs (KBP-85235). Don't know their rates as KB sold springs of all types/rates from a number of different manufactuerers depending on when you bought them. I think they are stock rated due to the ride quality. (For sale if anyone is interested). Ride heighth for the new springs is about a 1/4" higher than the KB's but I look for some settling as with most springs. As for the stock struts, as I said, I have my doubts about their damping ability with the 1,000lb springs. They feel pretty good playng around out where I go to burnish my brakes and rotors, but I will try them at the track Sunday to find out for sure. Will let you know.
Mr. Mysti said:
These are the springs I ran when I was racing American Sedan. I had probably 5 different sets of fronts and a couple sets of rears. I used to buy them through a circle track company for less than bluecoils retail. I'll do some looking to see if I can find them. Thanks for the link, I forgot all about them.
Darin
I also agree with you guys that the stock struts probably won't dampen 800 or higher spring rates. My goal is to find the balance of spring rates to do o/t and be bearable for the street, then buy the appropriate dampers.
Keep bringin' the spring tech please. I'm going to order some when I get back in town next week.
Darin
Keep bringin' the spring tech please. I'm going to order some when I get back in town next week.
Darin
I talked with Bilstein West Coast (1-858-386-5900) about our topic. '03'04 stock struts and shocks were made specificly for the car, rated to handle the 600lb spring and are crimped so they can't be revalved. They say you must stay within 20% of this rating to obtain best damping which would take us up to a 720lb spring. The Bilstein Heavy Duty, Bilstein Sport and Bilstein Cobra R struts are all that is available for a conventional spring set up from them. They are all too soft to handle a 1,000lb spring. Of course, there are other options like KONI,Tokico ect. but I'm talking only Bilstein here as that is what I'm going with. What is recommended is that you purchase an after market Bilstein strut and shock(they will tell you which one is optimum for your set up) and send it to them along with your spring rate, amount of lowering from that spring, make ,model and weight of the car, and they will custom valve your struts for you. Cost about $60.00 per unit & shipping, 10 day turn around. This is the direction I am going. By the way, the MM Race 2&3 Valved srtuts are for coil over set ups only. More later. (Bilstein East in N.Carolina is 1-704-663-7563) :beer:
I would talk with Carrera Shocks in Atlanta as they do 100% custom stuff too. I don't believe they will be cheap but they are very reputable.
Here's some Koni rebuild/revalve tech, it looks like a potential nightmare.
Going w/ new shocks/struts through the manufacturer seems a little smarter if you want custom valving, etc.
Going w/ new shocks/struts through the manufacturer seems a little smarter if you want custom valving, etc.
As a note... The 03-04 Cobra Bilstein Struts are MUCH improved over the 00 R Struts... I had both with 375# coilovers. (Which have a greater wheel rate than the 1000# spring.)
The problem with conventional springs with higher rates, is they cause more bind and distort the stock rubber control arm bushings... and a 1000# spring will feel as firm as perhaps a 400# coilover from the extra bind.
The problem with conventional springs with higher rates, is they cause more bind and distort the stock rubber control arm bushings... and a 1000# spring will feel as firm as perhaps a 400# coilover from the extra bind.
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