O.E. Size Rally Springs [Archive]

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odi

10-28-2008, 09:26 AM

Hey guys,

I was considering pushing the Ground Control kits for our cars with agx's and D-specs. But doing the math it would not be that great of an outcome. Considering Eibach or even swift Springs block height limits travel and the cost to set it up with minimal coil bind is not economical.

I can do a run of springs of a specific rate for front and rear that would be a O.E. replacement (will fit on original struts, agx, d-specs...). I can make the free length longer for raised ride height. If enough of you guys want springs, I will make them.

I need some feedback on spring rates desired and also what year of wrx to model after. I will also need a wrx at the shop to throw on the prototypes and make sure ride height is good. I will consult with a engineer about all of our demands.

Springs would cost around $330 for a set.

KevinWelker

10-28-2008, 09:37 AM

Odi, I would say you should go with the 04+ rear springs for the Impreza. They take a different top mounting but are pretty common these days.

As for rate I would say something like 225/195 would be suitable for gravel use although I am not sure if the dampers would handle that.

If you can't find any other cars I might be able to lend you my 2004 STi.

odi

10-28-2008, 09:42 AM

Thanks Kevin. The original dampers would not be able to handle an increased spring rate well. But the affordable options like agx's and d-specs would be perfect with some firmer rates. I tried 230/210 on my 2002 wagon. It felt very aggresive but could be a bit too much for many.

williaty

10-28-2008, 09:42 AM

Yeah, definitely go with the 04-07 style spring as you'll have the biggest market for them and it's very easy for the 02-03 guys to convert to that style. With the STi take offs being 224/192 and basically stock ride height, you'll need to be different. I would suggest either 225/225 or 250/225 and a 0.5-1.0" lift from stock ride height.

rollo

10-28-2008, 10:03 AM

Hey Odi.. you have an Evo at the shop though huh? :D

odi

10-28-2008, 10:10 AM

You and I would be the only ones to benefit from gravel products for an EVO. :-(

rollo

10-28-2008, 12:07 PM

Well I can think of about ten others, but yeah I see your point. Shame though.

Rally OBXT

10-28-2008, 12:52 PM

I would say 225 front and 200 rear and raising the car 1/2" to 1". It seems to be what most people here want. 250F / 225R is also a good rate, some people run it for stage rally.

STiXT6

10-28-2008, 07:18 PM

I would totally be down for a set. I need to get rid of these Tein Ss that the guy before me put on the car.

JacksonRally

10-28-2008, 07:39 PM

1'' lift kits now available

http://www.dirtyimpreza.com/forums/showthread.php?p=103087#post103087

Rally OBXT

10-28-2008, 08:06 PM

^^ Very nice Kyle. This is good because now you don't have to get a "lifting" spring. This would work very well with some of Odi's upgraded O.E. size spring rates.

williaty

10-28-2008, 08:16 PM

Man, that is A LOT for those lift kits.

JacksonRally

10-28-2008, 08:36 PM

Man, that is A LOT for those lift kits.

In comparison to what? Please provide more info....

I am providing a complete front and rear lift kit with hardware. I believe this is a fair price for a high quality product.

Kyle
JacksonRally@gmail.com

blkhatch

10-29-2008, 10:37 AM

im down for springs. i think it would be a great upgrade for people who do not want to spend the cash on coils. will go great with JR's lift kit.

williaty

10-29-2008, 10:41 AM

The problem with not making taller springs (utilizing the JR shims) is that we already have a spring that does that and costs only $50. The Feal springs will have to be meaningfully different to sell well.

lorenkb

10-29-2008, 10:59 AM

I want a set of WRX wagon specific springs with 225/200 rate. I don't want to shim, and I don't want the weird ride height given by STi springs on a wagon. Stock or slightly lifted (no more than 1"). However, there's enough caveats thrown in there that I don't see this spring combo selling well. :?

Oh, and Kyle you whore, don't you have your own thread for your lift kit? :punch: :tongue:

JacksonRally

10-29-2008, 06:43 PM

Oh, and Kyle you whore, don't you have your own thread for your lift kit? :punch: :tongue:

Haha I also have your discounted prices for your body panels....now your gonna have to wait :punch:

lorenkb

10-29-2008, 10:42 PM

williaty

10-29-2008, 10:46 PM

*Points at checkbook*
You want some more of this? I thought so. Now gimme my prices you bastard!
*Slaps Kyle with checkbook*
This forum rules!

BTW, yeah, if you can get me the rates used on a rally car, I can tell you the resultant frequencies. Or vice versa, I just need to know for sure one end of the equation or the other.

I know SoJ published the WRC Group N specs/setups for their cars the year after they ran, so if someone can remember where that is, the data is there.

ArcticWolf

10-29-2008, 10:57 PM

This page? http://www.subaru-sti.co.jp/e/GRN/tec_info/index.html

williaty

10-29-2008, 11:00 PM

:huh: That looks like the right page but it doesn't list the spring rates. Dunno.

ArcticWolf

10-30-2008, 12:15 AM

Another thought on spring rates... does anyone know, or have all the info to calculate, what suspension frequency is common on modern rally cars?

Rates of 225/200 would put an 07 wagon at ~1.6/1.8 Hz. I've seen reference to autocross guys shooting for a range of 1.9 to 2.2, and rally cars as low as 1.2. I'm all for choosing different spring rates if there is a better frequency to shoot for for our purposes (rallyx with some occasional abuse on the rough stuff).

Reference I believe you are remembering from is Don Alexander's High Performance Handling book ( http://books.google.com/books?id=BJUVdn5SMBgC&pg=PA41&lpg=PA41&dq=rally+car+suspension+frequency&source=web&ots=rO6xg__Gvx&sig=A4l1xHD3f8otsHcUbnNp6YFZv3o&hl=en&sa=X&oi=book_result&resnum=6&ct=result#PPA41,M1 ), Page 41 if that link sucks.

To memory, the word around the campfire is the stock STI springs are very similar to about what the rally cars use, and I've a nagging suspicion that Subaru tweaked them to be general purpose (rough capable, leaning towards tarmac), and a slight nod to our crappy roads. The JDM STI pinks aren't much higher in rate (250/220ish), likely tailored to japan's smoother roads. The tarmac/gymkhana springs are what they claim to be, tarmac only (325+/275+). NorthUrsalia's website lists DMS 50mm gravels as 275/225, and to memory SubieGal's wagon runs 225/180. EDIT: Tein Gravels are 252/196.

So really, stock STI springrate give or take (lower rate? progressive?), with more clearance.

blkhatch

10-30-2008, 06:28 AM

what would the hieght be with sti springs on a wrx sedan?

lorenkb

10-30-2008, 08:44 AM

BTW, yeah, if you can get me the rates used on a rally car, I can tell you the resultant frequencies. Or vice versa, I just need to know for sure one end of the equation or the other.

Wait, so you have curb weight, unsprung weight front/rear, and weight distribution front/rear for one of Subaru's rally cars? Cough it up man, I want!

Reference I believe you are remembering from is Don Alexander's High Performance Handling book ( http://books.google.com/books?id=BJUVdn5SMBgC&pg=PA41&lpg=PA41&dq=rally+car+suspension+frequency&source=web&ots=rO6xg__Gvx&sig=A4l1xHD3f8otsHcUbnNp6YFZv3o&hl=en&sa=X&oi=book_result&resnum=6&ct=result#PPA41,M1 ), Page 41 if that link sucks.

To memory, the word around the campfire is the stock STI springs are very similar to about what the rally cars use, and I've a nagging suspicion that Subaru tweaked them to be general purpose (rough capable, leaning towards tarmac), and a slight nod to our crappy roads. The JDM STI pinks aren't much higher in rate (250/220ish), likely tailored to japan's smoother roads. The tarmac/gymkhana springs are what they claim to be, tarmac only (325+/275+). NorthUrsalia's website lists DMS 50mm gravels as 275/225, and to memory SubieGal's wagon runs 225/180. EDIT: Tein Gravels are 252/196.

So really, stock STI springrate give or take (lower rate? progressive?), with more clearance.

Yep, thats the book. Hooray for google books!

I really think the suspension frequency given in that book for rally is on the very low end of things. Unless I'm missing something it's impractical to go as low as 1.2 Hz on our cars. You can get the total weight up to 3600 lbs, shave 20 lbs per corner in unsprung weight, and with 200/185 spring rates the frequencies are still up at 1.37/1.56

So... assuming STI rates are similar to those used on the rally cars, and that there isn't some crazy difference between the sprung weight per corner on our cars VS the rally cars, I'm sticking with wanting 225/200 rate springs.

Slim

10-30-2008, 09:31 AM

USDM STI Pinks. 223/195 FTW!

I love these springs. =)

odi

10-30-2008, 12:04 PM

If most of you guys are happy with using STI springs than there would be no need for me to make springs.

Are most of you guys ok with the lower ride height of the STI springs?

ArcticWolf

10-30-2008, 01:50 PM

I really think the suspension frequency given in that book for rally is on the very low end of things. Unless I'm missing something it's impractical to go as low as 1.2 Hz on our cars. You can get the total weight up to 3600 lbs, shave 20 lbs per corner in unsprung weight, and with 200/185 spring rates the frequencies are still up at 1.37/1.56

So... assuming STI rates are similar to those used on the rally cars, and that there isn't some crazy difference between the sprung weight per corner on our cars VS the rally cars, I'm sticking with wanting 225/200 rate springs.

FWIW, the stock suspension on a 2.5i (and the WRX, give or take a minor amount) is 1.32/1.39. So no, not really practical without a lot of extra height, or using the struts to do the spring's job. I'm assuming 60/40 split, and no people in the car - just using the curb weight.

Oh, and the curb weight of a WRC car is 1230kg. They go under, and add things to raise it back up to the 1230 minimum, while fiddling with the weight distribution. Dunno what the final distribution is like, though.

williaty

10-30-2008, 05:41 PM

If most of you guys are happy with using STI springs than there would be no need for me to make springs.

Are most of you guys ok with the lower ride height of the STI springs?
I'm really happy with the USDM STi take-off rates. I'm less than thrilled with the height. I, personally, would like spring with the STi-rates I have now, but a ride about an inch higher to help me keep my headers and ALK out of the dirt.

RA Limited

11-03-2009, 08:56 PM

I agree- i'd like STi rates but more height in the spring, so i don't have to deal with/buy spacers. An extra inch or two (over the STi spring) would be fine for the D-Specs, right?

Sorry for bringing back an old thread.

ALSO- i was given a set of stock (black, not pink) JDM STi Springs, need to verify if they are 04 or 05... do we know what the rates are on them?
Is an 04 JDM STi the same as 05 in the states (as in- 114.3)? Don't most of the models here precede the states by a year (in regards to subaru)?

williaty

11-03-2009, 08:59 PM

If they're just base JDM STi springs, they're only a little stiffer than USDM WRX springs. The JDM Spec C car is the one that has the same rates as the USDM STi.

Rally OBXT

11-03-2009, 09:44 PM

Wow, this came back after sitting for a year? Interesting.

RA Limited

11-04-2009, 02:34 PM

If they're just base JDM STi springs, they're only a little stiffer than USDM WRX springs. The JDM Spec C car is the one that has the same rates as the USDM STi.

They are black, and they came off a 04 or 05 STi my friend bought new. I need to ask him the year. Not all JDM STi springs are pink.

rallyimprezive

11-05-2009, 01:30 PM

I agree with what has been said about STI rates. And that it would be great to have a little more length. BUT, the real trick is to keep the strut cycling in its optimal operating range. That is where ODI's inserts come in.

So Odi, if the STI springs are a bit short to work well with your inserts, then you could probably sell a cool package deal that includes longer springs with STi rates.

I would buy them.

rallyimprezive

11-05-2009, 01:34 PM

Wow, this came back after sitting for a year? Interesting.

I think it is because the perfect "weeked rally warrior" suspension still hasnt been found for a reasonable price.

rollo

11-05-2009, 01:42 PM

Chris are you really rocking a Sambar? Where are the pics of that? :D

Rally OBXT

11-05-2009, 02:45 PM

I think it is because the perfect "weeked rally warrior" suspension still hasnt been found for a reasonable price.

It has, you just aren't looking hard enough. :mrgreen:

Struts = Tokico D-spec or KYB AGX's
Springs = USDM Sti

simple, rugged and cheap.

rallyimprezive

11-05-2009, 07:42 PM

It has, you just aren't looking hard enough. :mrgreen:

Struts = Tokico D-spec or KYB AGX's
Springs = USDM Sti

simple, rugged and cheap.

seen that combo, seems pretty popular. Just seems like it would a tad low. No?

Rally OBXT

11-06-2009, 08:17 AM

Depends on what car you have.....I have a CG, so the springs gave me a small lift. If you have a GD, it won't lift you at all. If you are looking for a small lift, you can get the Jackson Rally strut spacers.

Personally, if I was on the market for a new suspension, I would go with the FEAL strut inserts and STI or similar springs.

rallyimprezive

11-06-2009, 08:23 AM

jbrady

11-21-2009, 01:36 AM

What are these "inserts".....
The Sti spring are very popular but we need the sti rates with an inch lift without a strut spacer so we get that extra inch of bump travel thats so important especially since with the sti spring they bring ya down close to the stops. Im currently running WRX springs again on my 02 WRX and it lifted me back up about an inch over the STI springs. My Ohlin Fixed Perch have been revalved to give me more compression damping which has proven a very good setup for me. But having the STI rates would still be best i think.