drivemusicnow
15+ Year Contributor
- 1,444
- 30
- Nov 15, 2004
-
Germany,
Europe
Soooo as it goes, I've finally saved enough pennies to revamp the suspension for my 1g track car. I'm a graduating senior mechanical engineering major and am taking a very analytical approach to this. This would be all well and good except my analysis is leaving me without an ideal choice. I've separated the components and these are my thoughts on each. (This is assuming a full track car, bushings/active toe etc, and measurements have been taken care of) Due to class rules/restrictions, I'm not going to be relocating any of the suspension components
Struts/dampers
KYB, Megan/Ksport/d2, tein: The dampers on these products are generally terrible. They do have the positive aspect of being super cheap.
Koni: the OTS yellows, while being a technically good shock don't provide the performance I'm looking for. They are too soft in compression, and the rebound adjustment is typically only good for matching the shocks. While Dennis Grant may think they're the best option, I think with a little creativity we can do better. My backup option would be to have them revalved however at ~75$ per corner, that increases the cost significantly.
JIC: The stock JICs have been proven to have bad dampers. They've also proven to support fast cars when purchased from Mueller. The people that have shock dyno'd them have responded with similar amounts of disgust. Being the engineer that I am, I refuse to pay close to $2000 for the shocks from John Mueller without knowing what I'm buying.
Hotbits: I like this option with a few concerns. The shock has been dyno proven, they offer a DA option for a bit more money and I can have them rebuilt easily and cheaply. The negatives are the initial cost (2146$ for the DAs, without front or rear top mounts) add the cost of their top mounts (we'll discuss lower) or making my own and you end up with almost 2700$ for something that is as of yet, mostly unproven in a road course setting.
Koni Race Dampers
Now, most of the koni race offerings are expensive or unusable, but
Koni just happens to make a series of dampers that is quite interesting to me. I've been talking to Phil at truechoice about the possibility of using either the single or double adjustable (8611 or 8610). Unlike most of their race dampers that are eyelets on both ends, these are insert style replacement dampers with threaded strut rods. The SA are listed at 187$ apeice, while the doubles are close to 310. I think what they did here is take standard koni yellows, shorten the shock body, increase and narrow damping forces and offer it as a generic part rather than vehicle specific. I was also hoping that some one had some blown stock struts they could take some measurements for me, or that I could purchase them. I really would like to make the koni race shocks a viable option, but I just don't have the time right now to go searching through 50 classifieds emailing people for stock struts.
Top Mounts
The two off the shelf options are RRE's and Ground controls. RRE's is superior because of the 3 piece design that allows for better shock articulation. The disadvantage of both is that they're built for a stock shaft size and I'm not sure if the koni race shocks or the Hotbits use the same size (have emails out to find out). The Hotbits have the option to come with their own top mounts however they do not separate the car weight forces from the damper forces which is known to prematurely wear the spherical bearing. They also don't use a thrust bearing which can make adjustment on the car more difficult.
Spring rates
There are a couple different ways to solve for this. The "correct" way is to solve for the roll stiffness front and rear which includes suspension geometry, springs, and ARBs. I'm still calculating this as I don't have the ability to measure a couple things right now. I go to a heavily automotive biased university, which allows me access to some pretty cool pieces of suspension design software. I should have an analysis prepared in a couple weeks. (that is, if finding a job and finishing up my 24 credit hours of classes doesn't stop me) Either way, hypercoil springs and I'm initially trying them without helpers, and 8 inches tall. I'll update this as I go. (initial, un checked and guestimated numbers give me rounded values of 450/450 front and rear with stock bars, and 450/400 with the RM rear bar)
I'd like to hear some thoughts and opinions. I've got too much time into this that I might be too close to see something obvious. I'm willing to put about 2500$ into it, but I'd obviously like to do something cheaper.
Struts/dampers
KYB, Megan/Ksport/d2, tein: The dampers on these products are generally terrible. They do have the positive aspect of being super cheap.
Koni: the OTS yellows, while being a technically good shock don't provide the performance I'm looking for. They are too soft in compression, and the rebound adjustment is typically only good for matching the shocks. While Dennis Grant may think they're the best option, I think with a little creativity we can do better. My backup option would be to have them revalved however at ~75$ per corner, that increases the cost significantly.
JIC: The stock JICs have been proven to have bad dampers. They've also proven to support fast cars when purchased from Mueller. The people that have shock dyno'd them have responded with similar amounts of disgust. Being the engineer that I am, I refuse to pay close to $2000 for the shocks from John Mueller without knowing what I'm buying.
Hotbits: I like this option with a few concerns. The shock has been dyno proven, they offer a DA option for a bit more money and I can have them rebuilt easily and cheaply. The negatives are the initial cost (2146$ for the DAs, without front or rear top mounts) add the cost of their top mounts (we'll discuss lower) or making my own and you end up with almost 2700$ for something that is as of yet, mostly unproven in a road course setting.
Koni Race Dampers
Now, most of the koni race offerings are expensive or unusable, but
Koni just happens to make a series of dampers that is quite interesting to me. I've been talking to Phil at truechoice about the possibility of using either the single or double adjustable (8611 or 8610). Unlike most of their race dampers that are eyelets on both ends, these are insert style replacement dampers with threaded strut rods. The SA are listed at 187$ apeice, while the doubles are close to 310. I think what they did here is take standard koni yellows, shorten the shock body, increase and narrow damping forces and offer it as a generic part rather than vehicle specific. I was also hoping that some one had some blown stock struts they could take some measurements for me, or that I could purchase them. I really would like to make the koni race shocks a viable option, but I just don't have the time right now to go searching through 50 classifieds emailing people for stock struts.
Top Mounts
The two off the shelf options are RRE's and Ground controls. RRE's is superior because of the 3 piece design that allows for better shock articulation. The disadvantage of both is that they're built for a stock shaft size and I'm not sure if the koni race shocks or the Hotbits use the same size (have emails out to find out). The Hotbits have the option to come with their own top mounts however they do not separate the car weight forces from the damper forces which is known to prematurely wear the spherical bearing. They also don't use a thrust bearing which can make adjustment on the car more difficult.
Spring rates
There are a couple different ways to solve for this. The "correct" way is to solve for the roll stiffness front and rear which includes suspension geometry, springs, and ARBs. I'm still calculating this as I don't have the ability to measure a couple things right now. I go to a heavily automotive biased university, which allows me access to some pretty cool pieces of suspension design software. I should have an analysis prepared in a couple weeks. (that is, if finding a job and finishing up my 24 credit hours of classes doesn't stop me) Either way, hypercoil springs and I'm initially trying them without helpers, and 8 inches tall. I'll update this as I go. (initial, un checked and guestimated numbers give me rounded values of 450/450 front and rear with stock bars, and 450/400 with the RM rear bar)
I'd like to hear some thoughts and opinions. I've got too much time into this that I might be too close to see something obvious. I'm willing to put about 2500$ into it, but I'd obviously like to do something cheaper.