Boost Addict's 08 WRX Project - 233whp/334wtq - Pics, Vids, Dyno
03-04-2009, 04:14 PM
#106
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Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
When ordered as a full package, we will obviously present it for '09s as well by omitting the turbo. Lucky you!
03-13-2009, 11:48 PM
#107
Registered User
iTrader: (2)
Join Date: Feb 2009
Location: Pleasanton, Ca
Posts: 211
Car Info: 09 WRX Wagon, and 99 RS
So we spent several hours on Church's dyno yesterday, testing over and over to discover what was causing the intermittent boost cut I was hitting at the top of 4th gear. And why was I hitting 19-20 psi when the tune called for 15 at that rpm? It seemed the first run after each test was helping, then after a few more runs, it was the same issue again. We tried swapping pills from the boost line and the wastegate line, as the boost line appeared to be machined out slightly larger: no dice. We tried running no pill on the wastegate side, again... no fix. Then we thought, let's just remove both pills altogether. Again, same issue! It was starting to get pretty frustrating as nothing would fix the issue, and it was consistently just overboosting over 4500 rpm. Shawn's right hand man even suggested shimming the wastegate assembly closer to the turbo with 3 little washers... roughly forcing the gate open an additional 1/4 inch. Again, no fix.
However, we did notice a rattle develop after the shims were put in place. Initially we thought it was a heat shield, and after careful inspection... it wasn't. We then realized that as the wastegate was "fully" opening, it really WASN'T. The arm would only turn about 15 degrees, as opposed to a full 90 degrees. Ok, I think we're on to something now.
My buddy and I were racing around the web on our phones looking for answers... Does the WG really need to be bored out? It's not the boost solenoid, as that's responding perfectly well. It's not the pills at this point preventing the bleed out. So what is it? Finally, the right question was asked... "What downpipe are you running?" A friend of my friend had known someone with the same issue.
So here's what we know, and here's what we think:
We know, the Invidia DP was designed for the '08's without any anticipation that in '09, Subaru would put in a turbo with a larger wastegate. Fact.
We know, there's a plate built into the Invidia bellmouth collector that divides the exhaust and wastegate gases.
We know, there's an internal rattling sound during idle and deceleration coming from the back of the turbocharger, on the turbine side. This rattling sound was introduced when we shimmed the wastegate assembly closer to the turbo.
We know, by observation, that the wastegate is not opening fully.
We know, through dyno data, that the hotter it gets, the issue gets worse and we see increased overboosting.
We know, as heat increases, metal expands.
So here's what we think: The plate dividing the exhaust and wastegate side of the bellmouth on the Invidia collector is preventing the wastegate from fully opening. Considering all the observations and facts above, we're left with no other conclusion. We all nodded in agreement and I scooted off as Shawn had several appointments waiting (we were supposed to only be there for an hour, the favors this guy does for us
).
Afterwards, I made a quick call to Invidia to inquire whether or not they are aware of this probable issue. Sure enough, without denial, the rep admitted that it has been an issue in some applications. Apparently, it has not been consistent enough to yield a redesign... Or, not enough end-users meticulously tune their cars and monitor it's parameters the way I do. His suggestions? Just grind some of the plate off. Normally, I'd expect a manufacturer to fix the issue for me, but given the circumstances and time constraints, I was thankful enough that he openly admitted that it may be the cause. So this Sunday, we're hoping to take some pictures for you guys while we grind the divider plate, install the injectors and new fuel pump. Then it's off to the dyno again on Tuesday to see what this thing is really made of.
However, we did notice a rattle develop after the shims were put in place. Initially we thought it was a heat shield, and after careful inspection... it wasn't. We then realized that as the wastegate was "fully" opening, it really WASN'T. The arm would only turn about 15 degrees, as opposed to a full 90 degrees. Ok, I think we're on to something now.
My buddy and I were racing around the web on our phones looking for answers... Does the WG really need to be bored out? It's not the boost solenoid, as that's responding perfectly well. It's not the pills at this point preventing the bleed out. So what is it? Finally, the right question was asked... "What downpipe are you running?" A friend of my friend had known someone with the same issue.
So here's what we know, and here's what we think:
We know, the Invidia DP was designed for the '08's without any anticipation that in '09, Subaru would put in a turbo with a larger wastegate. Fact.
We know, there's a plate built into the Invidia bellmouth collector that divides the exhaust and wastegate gases.
We know, there's an internal rattling sound during idle and deceleration coming from the back of the turbocharger, on the turbine side. This rattling sound was introduced when we shimmed the wastegate assembly closer to the turbo.
We know, by observation, that the wastegate is not opening fully.
We know, through dyno data, that the hotter it gets, the issue gets worse and we see increased overboosting.
We know, as heat increases, metal expands.
So here's what we think: The plate dividing the exhaust and wastegate side of the bellmouth on the Invidia collector is preventing the wastegate from fully opening. Considering all the observations and facts above, we're left with no other conclusion. We all nodded in agreement and I scooted off as Shawn had several appointments waiting (we were supposed to only be there for an hour, the favors this guy does for us
).Afterwards, I made a quick call to Invidia to inquire whether or not they are aware of this probable issue. Sure enough, without denial, the rep admitted that it has been an issue in some applications. Apparently, it has not been consistent enough to yield a redesign... Or, not enough end-users meticulously tune their cars and monitor it's parameters the way I do. His suggestions? Just grind some of the plate off. Normally, I'd expect a manufacturer to fix the issue for me, but given the circumstances and time constraints, I was thankful enough that he openly admitted that it may be the cause. So this Sunday, we're hoping to take some pictures for you guys while we grind the divider plate, install the injectors and new fuel pump. Then it's off to the dyno again on Tuesday to see what this thing is really made of.
I have an 09 WRX. I have ordered an Invidia DP, a Perrin TMIC, and am going into EQ for install and a tune next Saturday. Soooooo....from the sounds of this post, the Invidia DP is going to be problematic for me. I guess I should just get a different DP?? Or is the grind down going to be something that can be done in with no problem? Other DP's (like Perrin) don't seem to have that divider plate at all. Is it usefull, just poorly designed for 09? Don't really know what to do here. Any advice you could give?
Also, was the install of the Perrin TMIC simply bolt-up? What did you do to the scoop channel (that plastic thing inside the scoop that channels airflow directly into the stock IC)?
Thanks...Advice is much appreciated.
03-17-2009, 12:31 AM
#108
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Hi,
I have an 09 WRX. I have ordered an Invidia DP, a Perrin TMIC, and am going into EQ for install and a tune next Saturday. Soooooo....from the sounds of this post, the Invidia DP is going to be problematic for me. I guess I should just get a different DP?? Or is the grind down going to be something that can be done in with no problem? Other DP's (like Perrin) don't seem to have that divider plate at all. Is it usefull, just poorly designed for 09? Don't really know what to do here. Any advice you could give?
Also, was the install of the Perrin TMIC simply bolt-up? What did you do to the scoop channel (that plastic thing inside the scoop that channels airflow directly into the stock IC)?
Thanks...Advice is much appreciated.
I have an 09 WRX. I have ordered an Invidia DP, a Perrin TMIC, and am going into EQ for install and a tune next Saturday. Soooooo....from the sounds of this post, the Invidia DP is going to be problematic for me. I guess I should just get a different DP?? Or is the grind down going to be something that can be done in with no problem? Other DP's (like Perrin) don't seem to have that divider plate at all. Is it usefull, just poorly designed for 09? Don't really know what to do here. Any advice you could give?
Also, was the install of the Perrin TMIC simply bolt-up? What did you do to the scoop channel (that plastic thing inside the scoop that channels airflow directly into the stock IC)?
Thanks...Advice is much appreciated.
Is it there for a purpose? Sure it is. It's there, theoretically, to divide the exhaust and wastegate gases to prevent the supposed turbulence that would create back pressure in the downpipe collector. But in all honesty, I don't think grinding it down will make much of a difference in terms of efficiency.
The Top Mount intercooler is a very simple bolt on. just loosely bolt it down, adjust it, making sure all hoses are in place, then secure it down tightly. Be careful not to strip any of the bolts.
As far as the rubber ducting is concerned, I just left mine as is. When the hood shuts, it seals onto the TMIC. While it does smash itself in a bit, it doesn't bother me at all.
Best of luck. Let us know of your results!
03-22-2009, 11:32 AM
#109
Registered User
iTrader: (2)
Join Date: Feb 2009
Location: Pleasanton, Ca
Posts: 211
Car Info: 09 WRX Wagon, and 99 RS
Had the work done at EQ yesterday. Here is the review:
https://www.i-club.com/forums/showpo...24&postcount=1
Basically they cut off the divider on the DP, so that it wouldn't be a problem. Perhaps it would have been "best" to grind down the wastegate side of the flange so that the wastegate door would have more clearance to swing open past the flange...but I just don't think that it matters all that much. If you really want to have no back-pressure from the wastegate, then get a divorced WG....otherwise aren't you just splitting hairs? It is all turbulent flow anyways.
The TMIC fit perfectly, and the stock hood scoop ducting fits pretty well with the new TMIC as well. I think that the ducting would be perfect with a little modification....which I have an idea about.
As I posted in the review, the car is making great smooth and safe power. So to sum up:
Invidia catted DP, with the divider flange cut off.
Perrin TMIC,
Hallman MBC,
Tune by Ed.
16.5 psi peak boost, ~250 WHP @ 5600 rpm, ~270 ft-lbf @ 3600 rpm, doesn't drop...still ~260 ft-lbf @5000 rpm...and SMOOTH all the way. And a little better gas mileage on the freeway. ~1-2 mpg.
Oh, and I asked Ed not to go over 16.5 psi, since I wanted safety first. I imagine that if I had wanted, he could have gotten another 5-10 WHP out of it. So I am getting better than stock STI power for ~$2k. Since I am not boosting the heck out of it, could probably have done nearly as well with the stock TMIC...which would have cut the cost to ~$1200. Not bad IMHO.
https://www.i-club.com/forums/showpo...24&postcount=1
Basically they cut off the divider on the DP, so that it wouldn't be a problem. Perhaps it would have been "best" to grind down the wastegate side of the flange so that the wastegate door would have more clearance to swing open past the flange...but I just don't think that it matters all that much. If you really want to have no back-pressure from the wastegate, then get a divorced WG....otherwise aren't you just splitting hairs? It is all turbulent flow anyways.
The TMIC fit perfectly, and the stock hood scoop ducting fits pretty well with the new TMIC as well. I think that the ducting would be perfect with a little modification....which I have an idea about.
As I posted in the review, the car is making great smooth and safe power. So to sum up:
Invidia catted DP, with the divider flange cut off.
Perrin TMIC,
Hallman MBC,
Tune by Ed.
16.5 psi peak boost, ~250 WHP @ 5600 rpm, ~270 ft-lbf @ 3600 rpm, doesn't drop...still ~260 ft-lbf @5000 rpm...and SMOOTH all the way. And a little better gas mileage on the freeway. ~1-2 mpg.
Oh, and I asked Ed not to go over 16.5 psi, since I wanted safety first. I imagine that if I had wanted, he could have gotten another 5-10 WHP out of it. So I am getting better than stock STI power for ~$2k. Since I am not boosting the heck out of it, could probably have done nearly as well with the stock TMIC...which would have cut the cost to ~$1200. Not bad IMHO.
04-14-2009, 01:05 PM
#110
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Had the work done at EQ yesterday. Here is the review:
https://www.i-club.com/forums/showpo...24&postcount=1
Basically they cut off the divider on the DP, so that it wouldn't be a problem. Perhaps it would have been "best" to grind down the wastegate side of the flange so that the wastegate door would have more clearance to swing open past the flange...but I just don't think that it matters all that much. If you really want to have no back-pressure from the wastegate, then get a divorced WG....otherwise aren't you just splitting hairs? It is all turbulent flow anyways.
The TMIC fit perfectly, and the stock hood scoop ducting fits pretty well with the new TMIC as well. I think that the ducting would be perfect with a little modification....which I have an idea about.
As I posted in the review, the car is making great smooth and safe power. So to sum up:
Invidia catted DP, with the divider flange cut off.
Perrin TMIC,
Hallman MBC,
Tune by Ed.
16.5 psi peak boost, ~250 WHP @ 5600 rpm, ~270 ft-lbf @ 3600 rpm, doesn't drop...still ~260 ft-lbf @5000 rpm...and SMOOTH all the way. And a little better gas mileage on the freeway. ~1-2 mpg.
Oh, and I asked Ed not to go over 16.5 psi, since I wanted safety first. I imagine that if I had wanted, he could have gotten another 5-10 WHP out of it. So I am getting better than stock STI power for ~$2k. Since I am not boosting the heck out of it, could probably have done nearly as well with the stock TMIC...which would have cut the cost to ~$1200. Not bad IMHO.
https://www.i-club.com/forums/showpo...24&postcount=1
Basically they cut off the divider on the DP, so that it wouldn't be a problem. Perhaps it would have been "best" to grind down the wastegate side of the flange so that the wastegate door would have more clearance to swing open past the flange...but I just don't think that it matters all that much. If you really want to have no back-pressure from the wastegate, then get a divorced WG....otherwise aren't you just splitting hairs? It is all turbulent flow anyways.
The TMIC fit perfectly, and the stock hood scoop ducting fits pretty well with the new TMIC as well. I think that the ducting would be perfect with a little modification....which I have an idea about.
As I posted in the review, the car is making great smooth and safe power. So to sum up:
Invidia catted DP, with the divider flange cut off.
Perrin TMIC,
Hallman MBC,
Tune by Ed.
16.5 psi peak boost, ~250 WHP @ 5600 rpm, ~270 ft-lbf @ 3600 rpm, doesn't drop...still ~260 ft-lbf @5000 rpm...and SMOOTH all the way. And a little better gas mileage on the freeway. ~1-2 mpg.
Oh, and I asked Ed not to go over 16.5 psi, since I wanted safety first. I imagine that if I had wanted, he could have gotten another 5-10 WHP out of it. So I am getting better than stock STI power for ~$2k. Since I am not boosting the heck out of it, could probably have done nearly as well with the stock TMIC...which would have cut the cost to ~$1200. Not bad IMHO.
nice results!We should be hacksawing that down pipe lip in the next couple weeks!
05-11-2009, 01:47 AM
#111
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
An update folks...
The stock clutch is officially gone.
It had been shuddering for the last month upon any gentle activation in 1st gear, but performing flawlessly upon any aggressive launch, until recently. I first discovered the passing of the clutch on Thursday morning while cruising in 4th gear. I down-shifted to 3rd for a moderate sprint. The speed didn't really increase while the RPM simply shot up without any resistance. Immediately, I figured the clutch had simply overheated momentarily. So I let the car cool down and took it out again several hours later. Got to the highway, tried accelerating in 5th (high load) and sure enough, the clutch had quit at just shy of a young 12,000 miles.
While this may sound like a premature failure to some, there are some things that should be taken into consideration. First and foremost, this clutch has been withstanding a lofty peak 334 wtq for the last several months in comparison to the pre-production figure of 236 wtq. Remember this graph?
Across the entire rev band, that is a significant torque increase which will very obviously take a toll on a clutch designed for the more modest curve. The original clutch had also gotten me through at least 8 trips to the drag strip consisting of a minimum of 3 runs per trip. Finally, the oem clutch has a delayed release when instantly dumped at a high rpm. This cooks the clutch in the name of preventing that immediate shock from abusing the actual drive train. Smart move.
So the car has been at the shop since Friday. I'm getting a new OEM clutch kit and new flywheel for good measure put in tomorrow morning. I flirted with the idea of upgrading to a sportier clutch and possibly a lighter flywheel while it's apart, but stuck to my philosophy of keeping a weak link. I've often discouraged people from upgrading their clutches, unless the clutch will simply not hold the torque you put through it once in gear. Obviously, many people recommended that I upgrade anyway. Naturally, I questioned myself quite a bit, did some research on flywheels and clutch kits and simply couldn't decide. I was invited to something of a dyno day that my tuner, Shawn Church, had going on with some MazdaSpeed folks. While there, I surveyed his opinion only to find that it solidified my own thoughts. But while I go about explaining the strain a strong clutch can place on a drive train, he cut through the explanation and made a very simple comment; a comment I'll never forget, and one I'm likely to echo for years to come. "The clutch is your fuse in an All Wheel Drive car." 8)
So what about the flywheel? I'm personally not a big fan of lighter revs in a street car. It can add a degree of difficulty to daily putts around town, which this car is used for most of the time. By that, I mean gentle take offs from lights will require more concentrated modulation of the throttle to avoid jerky starts or high let offs. The stock unit served me well, and so the stock unit it shall be. So what's next?
During my WRXs little hiatus, I've been driving around a 2003 V6 Mustang Coupe. The car is bone stock w/ 17 inch bullitt wheels being the only modification. I am going to just put this out there as it is my honest observation. The suspension felt considerably more composed than that of my WRX. For the record, I am on 17x8 rotas wrapped in 235 sticky Kumho XS rubber. The only modification to my actual suspension is the STI Pink Springs. I've mentioned before, that since I added the tires, the actual characteristics of the handling had worsened. I didn't realize how bad it really was until this weekend. Now, I'm not saying the Mustang would out handle the WRX through corners, but it sure as hell felt better. The current setup on my WRX produces an unacceptable amount of body roll that is put to shame by a live axled 'Stang. Furthermore, highway ride is gentle, yet composed, in the Mustang. My WRX, on the highway, will do the Macarena over every little bump, and continue wiggling even after the songs over. So what's the deal? We can send thank you cards to a stiff-walled, sticky tire combined with a luxury-soft set of shocks. Oh, and the Pinks? They've been divorced from my shocks since day one, and their relationship has worsened since the tire upgrade. On the stock rubber, the STI Pinks actually felt like a pretty decent improvement! So none of these parts can be blamed individually. It's when they were forced to work together that made them a bad combination. Like Ringo taking over the drums for Tool. It just doesn't work out.
A set of coilovers and sway bars were a plan for sometime down the line. They have just risen to the top of my priority list and I'm doing research as we speak. I am looking into getting them dialed in for a firm, well composed ride while dropping the front of the car about an inch. That said, I will soon have my STI Pinks for sale along with my STI front lip. The front lip already has some significant scratches on the surface that can probably be sanded out. The good news, is that it has no chips or cracks, but it won't be long if the front is lowered any more.
The obtrusive divider is still in the downpipe, and our website is still being worked on. My upgraded injectors and pump still remain in the trunk pending installation and re-tune. We've been so busy making contacts, overcoming set-up issues, and researching companies we want to work with that the clutch failure almost came as a, "Hey, let's start working on the WRX again!"
Thanks for your time.
The stock clutch is officially gone.
It had been shuddering for the last month upon any gentle activation in 1st gear, but performing flawlessly upon any aggressive launch, until recently. I first discovered the passing of the clutch on Thursday morning while cruising in 4th gear. I down-shifted to 3rd for a moderate sprint. The speed didn't really increase while the RPM simply shot up without any resistance. Immediately, I figured the clutch had simply overheated momentarily. So I let the car cool down and took it out again several hours later. Got to the highway, tried accelerating in 5th (high load) and sure enough, the clutch had quit at just shy of a young 12,000 miles. While this may sound like a premature failure to some, there are some things that should be taken into consideration. First and foremost, this clutch has been withstanding a lofty peak 334 wtq for the last several months in comparison to the pre-production figure of 236 wtq. Remember this graph?
Across the entire rev band, that is a significant torque increase which will very obviously take a toll on a clutch designed for the more modest curve. The original clutch had also gotten me through at least 8 trips to the drag strip consisting of a minimum of 3 runs per trip. Finally, the oem clutch has a delayed release when instantly dumped at a high rpm. This cooks the clutch in the name of preventing that immediate shock from abusing the actual drive train. Smart move.
So the car has been at the shop since Friday. I'm getting a new OEM clutch kit and new flywheel for good measure put in tomorrow morning. I flirted with the idea of upgrading to a sportier clutch and possibly a lighter flywheel while it's apart, but stuck to my philosophy of keeping a weak link. I've often discouraged people from upgrading their clutches, unless the clutch will simply not hold the torque you put through it once in gear. Obviously, many people recommended that I upgrade anyway. Naturally, I questioned myself quite a bit, did some research on flywheels and clutch kits and simply couldn't decide. I was invited to something of a dyno day that my tuner, Shawn Church, had going on with some MazdaSpeed folks. While there, I surveyed his opinion only to find that it solidified my own thoughts. But while I go about explaining the strain a strong clutch can place on a drive train, he cut through the explanation and made a very simple comment; a comment I'll never forget, and one I'm likely to echo for years to come. "The clutch is your fuse in an All Wheel Drive car." 8)
So what about the flywheel? I'm personally not a big fan of lighter revs in a street car. It can add a degree of difficulty to daily putts around town, which this car is used for most of the time. By that, I mean gentle take offs from lights will require more concentrated modulation of the throttle to avoid jerky starts or high let offs. The stock unit served me well, and so the stock unit it shall be. So what's next?
During my WRXs little hiatus, I've been driving around a 2003 V6 Mustang Coupe. The car is bone stock w/ 17 inch bullitt wheels being the only modification. I am going to just put this out there as it is my honest observation. The suspension felt considerably more composed than that of my WRX. For the record, I am on 17x8 rotas wrapped in 235 sticky Kumho XS rubber. The only modification to my actual suspension is the STI Pink Springs. I've mentioned before, that since I added the tires, the actual characteristics of the handling had worsened. I didn't realize how bad it really was until this weekend. Now, I'm not saying the Mustang would out handle the WRX through corners, but it sure as hell felt better. The current setup on my WRX produces an unacceptable amount of body roll that is put to shame by a live axled 'Stang. Furthermore, highway ride is gentle, yet composed, in the Mustang. My WRX, on the highway, will do the Macarena over every little bump, and continue wiggling even after the songs over. So what's the deal? We can send thank you cards to a stiff-walled, sticky tire combined with a luxury-soft set of shocks. Oh, and the Pinks? They've been divorced from my shocks since day one, and their relationship has worsened since the tire upgrade. On the stock rubber, the STI Pinks actually felt like a pretty decent improvement! So none of these parts can be blamed individually. It's when they were forced to work together that made them a bad combination. Like Ringo taking over the drums for Tool. It just doesn't work out.
A set of coilovers and sway bars were a plan for sometime down the line. They have just risen to the top of my priority list and I'm doing research as we speak. I am looking into getting them dialed in for a firm, well composed ride while dropping the front of the car about an inch. That said, I will soon have my STI Pinks for sale along with my STI front lip. The front lip already has some significant scratches on the surface that can probably be sanded out. The good news, is that it has no chips or cracks, but it won't be long if the front is lowered any more.
The obtrusive divider is still in the downpipe, and our website is still being worked on. My upgraded injectors and pump still remain in the trunk pending installation and re-tune. We've been so busy making contacts, overcoming set-up issues, and researching companies we want to work with that the clutch failure almost came as a, "Hey, let's start working on the WRX again!"
Thanks for your time.
05-11-2009, 10:19 AM
#112
Registered User
Join Date: Apr 2009
Location: Fremont, cA
Posts: 34
Car Info: 2004 WRX Hatchback
I know absolutely nothing about my subaru or the upgrades you are making but it makes me incredibly interested to see what I can do with mine if/when i apply the time and resources needed... Your car looks amazing and the results are even better.
05-21-2009, 01:43 AM
#113
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Happy to hear that man and thanks for the compliments! If you ever have any questions, feel free to PM or ask here and I will do my best to help!
05-21-2009, 01:44 AM
#114
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Update 05.20.2009
My research for Coilovers is complete. After a lot of reading, discussion and thought, I've ordered a set of BC Coilovers and selected a custom set of spring rates. In the meantime, I also set up a retail relationship with BC, so Treble Racing will be carrying BC Coilovers very soon for anyone interested.
Some Facts:
HOW TO PROMOTE UNDERSTEER - Heavier spring rates in FR, Softer spring rates in RR, Higher tire pressures in FR, Lower tire pressures in RR, Positive camber in FR, Negative Camber in RR, Stiffer sway bar in FR, Softer sway bar in RR.
HOW TO PROMOTE OVERSTEER - Lighter spring rates in FR, Heavier spring rates in RR, Lower tire pressures in FR, Higher tire pressures in RR, Negative camber in FR, Positive camber in RR, Softer sway bar in FR, Stiffer sway bar in RR.
A Little Background:
The vehicle drives off the lot with an abundance of UNDERSTEER. It's got the right formula for it, after all (Positive FR camber, Negative RR camber, Heavier FR spring rates, Lighter RR spring rates, 20 mm FR sway bar, 15 mm RR sway bar). When we added the STI springs, we didn't know the spring rates. We only read that it promised an overall stiffness over stock. Good enough to try, we though... So we ran the set and felt they were a pretty significant improvement over stock with both response and reduction in body roll. Mind you, we were still on the stock wheels and tires. Then came the proverbial wrench...
We bought an 8-inch wide wheel and employed a stiff-walled, 180 Treadwear Kumho XS rubber in a fat 235 width to stick to the road better. The result in grip was enormous! However, the overall impact on the vehicles handling dynamics was negative! By reducing the amount of give a tire has against the road, the force is then absorbed more so by the springs and struts. Suddenly, it was Understeer City all over again, and the dynamics felt significantly worse than stock. The stiff tires coupled with a soft set of OEM struts made the highway ride suffer in terms of stability. Over average bumps, the vehicle would bob and bounce... Unacceptable!
What's Out There?
We wanted to purchase a set of coilovers for the project car that we can also sell to the public. This allows us to give people drives, and provides us a very real experience that we can communicate over to our customers. I looked into design, features, durability and warranty. I will not directly compare each set that we have access to, but for the sake of comparing spring rates, I will mention what's significant.
Suspension Package:
FR: Spring Rate
RR: Spring Rate
Subaru OEM 2008 WRX:
FR: 2.7 kgf/mm (151 lbs/in)
RR: 2.4 kgf/mm (137 lbs/in)
Subaru OEM 2009 WRX:
FR: 3.9 kgf/mm (217 lbs/in)
RR: 3.5 kgf/mm (194 lbs/in)
BC Racing BR:
FR: 6 kgf/mm (334 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
BC Racing BR (Custom Rates for Boost Addict/Treble Racing):
FR: 8 kgf/mm (445 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
Cusco:
FR: 7 kgf/mm (390 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
Megan Racing Street:
FR: 6 kgf/mm (334 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
Tein Basic:
FR: 6 kgf/mm (334 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
Tein SS-P:
FR: 6 kgf/mm (334 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
HKS Hipermax III:
FR: 7 kgf/mm (390 lbs/in)
RR: 6 kgf/mm (334 lbs/in)
What Did I Select?
BC Racing gave me the option to select whatever spring rate I wanted. If I exceeded the supplied rate by more than 2 kgf/mm, they would re-valve the dampers to match. I remained within spec by raising the FR rate by only 2 kgf/mm. Considering that I have plans to dial in some Negative Camber in the front and add a larger rear sway bar down the line(both of which promote oversteer), I felt that the supplied 6k/8k pairing may be slightly too aggressive in the rear. And since the '09 WRX already is supplied with 3.9k FR spring rates, I felt that I'd rather raise the FR spring rate, rather than drop the RR rate.
What Do I Hope To Achieve?
I expect the Coilovers to be on my car within the next 2 weeks. My Kumho's are wearing fast and I'm planning on my next set of tires will be Falken Azenis RT-615s in a wider tread and smaller overall diameter(245/40/17 vs the current 235/45/17). Considering the fairly heavy rates I've selected, I imagine the tires should start getting a bit of a workout in the corners. I will play with the compression/rebound rates and report my findings back.
My overall goal is to achieve a very firm and solid highway ride(at the willing sacrifice of some comfort). I want the car to feel planted during cornering with minimal body roll. I am also expecting corner rotation to improve significantly while still remaining slightly on the safe side with a touch of understeer at the limit. Expect a complete review.
My research for Coilovers is complete. After a lot of reading, discussion and thought, I've ordered a set of BC Coilovers and selected a custom set of spring rates. In the meantime, I also set up a retail relationship with BC, so Treble Racing will be carrying BC Coilovers very soon for anyone interested.
Some Facts:
HOW TO PROMOTE UNDERSTEER - Heavier spring rates in FR, Softer spring rates in RR, Higher tire pressures in FR, Lower tire pressures in RR, Positive camber in FR, Negative Camber in RR, Stiffer sway bar in FR, Softer sway bar in RR.
HOW TO PROMOTE OVERSTEER - Lighter spring rates in FR, Heavier spring rates in RR, Lower tire pressures in FR, Higher tire pressures in RR, Negative camber in FR, Positive camber in RR, Softer sway bar in FR, Stiffer sway bar in RR.
A Little Background:
The vehicle drives off the lot with an abundance of UNDERSTEER. It's got the right formula for it, after all (Positive FR camber, Negative RR camber, Heavier FR spring rates, Lighter RR spring rates, 20 mm FR sway bar, 15 mm RR sway bar). When we added the STI springs, we didn't know the spring rates. We only read that it promised an overall stiffness over stock. Good enough to try, we though... So we ran the set and felt they were a pretty significant improvement over stock with both response and reduction in body roll. Mind you, we were still on the stock wheels and tires. Then came the proverbial wrench...
We bought an 8-inch wide wheel and employed a stiff-walled, 180 Treadwear Kumho XS rubber in a fat 235 width to stick to the road better. The result in grip was enormous! However, the overall impact on the vehicles handling dynamics was negative! By reducing the amount of give a tire has against the road, the force is then absorbed more so by the springs and struts. Suddenly, it was Understeer City all over again, and the dynamics felt significantly worse than stock. The stiff tires coupled with a soft set of OEM struts made the highway ride suffer in terms of stability. Over average bumps, the vehicle would bob and bounce... Unacceptable!
What's Out There?
We wanted to purchase a set of coilovers for the project car that we can also sell to the public. This allows us to give people drives, and provides us a very real experience that we can communicate over to our customers. I looked into design, features, durability and warranty. I will not directly compare each set that we have access to, but for the sake of comparing spring rates, I will mention what's significant.
Suspension Package:
FR: Spring Rate
RR: Spring Rate
Subaru OEM 2008 WRX:
FR: 2.7 kgf/mm (151 lbs/in)
RR: 2.4 kgf/mm (137 lbs/in)
Subaru OEM 2009 WRX:
FR: 3.9 kgf/mm (217 lbs/in)
RR: 3.5 kgf/mm (194 lbs/in)
BC Racing BR:
FR: 6 kgf/mm (334 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
BC Racing BR (Custom Rates for Boost Addict/Treble Racing):
FR: 8 kgf/mm (445 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
Cusco:
FR: 7 kgf/mm (390 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
Megan Racing Street:
FR: 6 kgf/mm (334 lbs/in)
RR: 8 kgf/mm (445 lbs/in)
Tein Basic:
FR: 6 kgf/mm (334 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
Tein SS-P:
FR: 6 kgf/mm (334 lbs/in)
RR: 5 kgf/mm (278 lbs/in)
HKS Hipermax III:
FR: 7 kgf/mm (390 lbs/in)
RR: 6 kgf/mm (334 lbs/in)
What Did I Select?
BC Racing gave me the option to select whatever spring rate I wanted. If I exceeded the supplied rate by more than 2 kgf/mm, they would re-valve the dampers to match. I remained within spec by raising the FR rate by only 2 kgf/mm. Considering that I have plans to dial in some Negative Camber in the front and add a larger rear sway bar down the line(both of which promote oversteer), I felt that the supplied 6k/8k pairing may be slightly too aggressive in the rear. And since the '09 WRX already is supplied with 3.9k FR spring rates, I felt that I'd rather raise the FR spring rate, rather than drop the RR rate.
What Do I Hope To Achieve?
I expect the Coilovers to be on my car within the next 2 weeks. My Kumho's are wearing fast and I'm planning on my next set of tires will be Falken Azenis RT-615s in a wider tread and smaller overall diameter(245/40/17 vs the current 235/45/17). Considering the fairly heavy rates I've selected, I imagine the tires should start getting a bit of a workout in the corners. I will play with the compression/rebound rates and report my findings back.
My overall goal is to achieve a very firm and solid highway ride(at the willing sacrifice of some comfort). I want the car to feel planted during cornering with minimal body roll. I am also expecting corner rotation to improve significantly while still remaining slightly on the safe side with a touch of understeer at the limit. Expect a complete review.
Last edited by Boost Addict; 05-21-2009 at 05:35 PM.
05-21-2009, 11:40 AM
#116
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Meanwhile, my WRX is sleeping in the garage without a trunk. We've begun development on our Carbon Fiber Trunk that will be released in the very near future.
06-08-2009, 12:26 AM
#119
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
Folks,
With regards to my impressions about the new coilovers, I'll leave you with a few questions.
Want your 4-door sedan to feel as firm, planted and composed as the likes of a 911? Would you like an independently adjustable ride height that does not compromise your spring travel or pre-load? Care to reduce your body roll to almost nothing?
I have a lot to share about the BCs, but I owe it to myself and everyone else to spend some more miles behind the wheel before i can review them in full.
For now, I leave you with some more suspension components that I've ordered in the name of better bite, snappier response, better rotation, and putting a nail in the body roll coffin. Ladies and Gentlemen, behold:
Perrin 25mm Adjustable Front Sway Bar
Perrin 22mm Adjustable Rear Sway Bar
Perrin Front Endlinks
Perrin Rear Endlinks
Coming Soon.
With regards to my impressions about the new coilovers, I'll leave you with a few questions.
Want your 4-door sedan to feel as firm, planted and composed as the likes of a 911? Would you like an independently adjustable ride height that does not compromise your spring travel or pre-load? Care to reduce your body roll to almost nothing?
I have a lot to share about the BCs, but I owe it to myself and everyone else to spend some more miles behind the wheel before i can review them in full.
For now, I leave you with some more suspension components that I've ordered in the name of better bite, snappier response, better rotation, and putting a nail in the body roll coffin. Ladies and Gentlemen, behold:
Perrin 25mm Adjustable Front Sway Bar
Perrin 22mm Adjustable Rear Sway Bar
Perrin Front Endlinks
Perrin Rear Endlinks
Coming Soon.
06-13-2009, 10:58 PM
#120
VIP Member
Thread Starter
Join Date: Apr 2003
Location: Orange County, CA
Posts: 846
Car Info: 08 WRX - 401whp/408wtq
A few items on order:
You've already seen these. PERRIN 25mm Front Sway Bar, PERRIN 22mm Rear Sway Bar, PERRIN Front Endlinks, PERRIN Rear Endlinks:
Upgrading to a 2008 STI Brake Master Cylinder:
Upgrading to 2004-Spec Brembo Big Brake Kit:
And to finally complete my In-Car Electronics, I am adding in a Pioneer Premier F90BT - in-dash touchscreen Head Unit w/ built in GPS/Nav, Bluetooth (in lieu of the CiG-Blue already installed), iPod Audio+Video, DVD:
You've already seen these. PERRIN 25mm Front Sway Bar, PERRIN 22mm Rear Sway Bar, PERRIN Front Endlinks, PERRIN Rear Endlinks:
Upgrading to a 2008 STI Brake Master Cylinder:
Upgrading to 2004-Spec Brembo Big Brake Kit:
And to finally complete my In-Car Electronics, I am adding in a Pioneer Premier F90BT - in-dash touchscreen Head Unit w/ built in GPS/Nav, Bluetooth (in lieu of the CiG-Blue already installed), iPod Audio+Video, DVD: