Dave's Subie Fah-Q

[BustedUjoint]

nice write up Dave! Glad to actually see some useful information come out of TST for once ;)

[DaveSTi]

Originally Posted by BustedUjoint

nice write up Dave! Glad to actually see some useful information come out of TST for once ;)

haha thank you!

[ndubz]

Very nice info dude. Im glad to see Ive done alot right lol. The "me too" ftmfw

[Khellen]

Originally Posted by DaveSTI

Hey, you wanted the big monster...now you've gotta feed it...and it only eats one thing...your cash.

Haha epic. Great writeup! Wish this was around when I was starting to build my car, would have saved a LOT of looking at 50 seperate threads on Nabisco. I think this convinced me to pick up roll center adjustment kit. Also feel better about my choice of picking up an 18g for my car.

Btw...how are you liking your evo X compared to your old sti?

[DaveSTi]

Originally Posted by Khellen

Haha epic. Great writeup! Wish this was around when I was starting to build my car, would have saved a LOT of looking at 50 seperate threads on Nabisco. I think this convinced me to pick up roll center adjustment kit. Also feel better about my choice of picking up an 18g for my car.

Btw...how are you liking your evo X compared to your old sti?

Thank you, I'm glad that you found the information useful!

The roll center kit will also increase roll stiffness up front due to its effect on the camber curve so you won't need to run the front swaybar as stiff with one.

The Evo is exactly what I wanted. It's comfortable over the rough stuff, quiet inside, has a lot of features to play with, handles better than my old STi did, and is as quick in a straightline with just an air filter and a reflash.

Hard to beat it for the money.

[Khellen]

Originally Posted by DaveSTi

The roll center kit will also increase roll stiffness up front due to its effect on the camber curve so you won't need to run the front swaybar as stiff with one.

I've got adjustable front and rear 27mm whiteline sways both set to 25mm atm. Is the stiffness from the roll center a huge difference or just a tad bit stiffer? It's not my DD so it's not a big deal, just not sure if I want it much stiffer on the street.

Btw, you are dead on about the BC coilovers, I love mine but they have no travel. On the highway when I hit bumps even set on medium they send me airborne haha.

Originally Posted by DaveSTi

The Evo is exactly what I wanted. It's comfortable over the rough stuff, quiet inside, has a lot of features to play with, handles better than my old STi did, and is as quick in a straightline with just an air filter and a reflash.

Wait, a stock suspension evo X gsr handles better then your fully modded STI? Or are you comparing stock to stock?

[DaveSTi]

Originally Posted by Khellen

I've got adjustable front and rear 27mm whiteline sways both set to 25mm atm. Is the stiffness from the roll center a huge difference or just a tad bit stiffer? It's not my DD so it's not a big deal, just not sure if I want it much stiffer on the street.

Btw, you are dead on about the BC coilovers, I love mine but they have no travel. On the highway when I hit bumps even set on medium they send me airborne haha.

it's a noticeable difference for sure. since you're set at 25mm all around, you're good with the sways...i ran the 27-29mm front bar first and that was overkill with the coilovers spring rate then the RCA kit.

haha, yeah they're fun like that!

Wait, a stock suspension evo X gsr handles better then your fully modded STI? Or are you comparing stock to stock?

STi was faster in the midrange but around the same in the quartermile since it had to be shifted into 5th gear.

Evo with the rear swaybar and on the advan tires is all over the STi in the turns....the STi on RE070s would push at its limit while the Evo hits the same mph or higher in turns and stays neutral. At an autocross, I was running in BSP without the rear sway and was a few tenths off of an 05 STi with coilovers, etc. for most of the morning.

It's just a better handling platform, IMO. The car pulls .99g stock. does the slalom in over 72mph stock. for comparison's sake, the stock STi did .92g and 67mph. With all the mods on my STi, i'm sure those numbers improved, but I'm not sure by how much....especially around a track. At the very least, the Evo is more forgiving at the limit and seems to have a much deeper dig into a curve without requiring me to really work the pedals or wheel. It's a lot more intuitive to go fast in.

[Khellen]

My coilover spring rates are 10k / 8k. It's a stiff ride, but its definitely a decent ride until I hit large bumps (due to the lack of travel).

Hmmm...may have to pick up an evo X for my next car, sounds to good to pass up.

[DaveSTi]

Originally Posted by Khellen

My coilover spring rates are 10k / 8k. It's a stiff ride, but its definitely a decent ride until I hit large bumps (due to the lack of travel).

Hmmm...may have to pick up an evo X for my next car, sounds to good to pass up.

Wow that is stiff for the GD...my T2's were 9k/7k and I was contemplating knocking them down to 7k/5k for a street car.....the T2's have almost two more inches of travel than the BCs too!

It's an amazing car. I don't hand out praise for OEM setups very often, but Mitsu nailed the mark on this car. Very little to improve on unless you want an all out track car (and the Evo X piloted by Ryan Gates cleaned house in TA this year).

[TROLL]

Dave... I had always believed that it was a common misconception (even with shops) that 'adjustable' swaybars can adjust from 23, 25 or 27mm for example... however this is technically incorrect because the 27mm swaybar is actually a measurement of the diameter of the bar, which never changes. What does change is the mounting point on either end, which should instead be arbitrarily thought of as soft, medium, stiff. Further, every bar is different since materials and design vary from one to the next.
From what I'm reading here I think you'll disagree, but I'm hoping you can explain what your thoughts are on this one.

[DaveSTi]

Originally Posted by TROLL

Dave... I had always believed that it was a common misconception (even with shops) that 'adjustable' swaybars can adjust from 23, 25 or 27mm for example... however this is technically incorrect because the 27mm swaybar is actually a measurement of the diameter of the bar, which never changes. What does change is the mounting point on either end, which should instead be arbitrarily thought of as soft, medium, stiff. Further, every bar is different since materials and design vary from one to the next.
From what I'm reading here I think you'll disagree, but I'm hoping you can explain what your thoughts are on this one.

Oh, I won't disagree with you at all because you are 100% correct!

The diameter of the bar is what drives the initial soft "setting" on bars. Like you stated, a Whiteline 27mm is 27mm in diameter. Here is where swaybar math gets fuzzy...

The increase in bar stiffness comes from the location of the mounting holes on the bar...closer to the bar, the stiffer it is. Now, how much stiffer are these holes? That is where the construction of the bar comes into play as well as the location of the mounting holes. This is explained in a percentage increase.

By using the known effective bar rate of 27mm (let's make this easy and say its 500 lbs of effective rate), Whiteline can say that the next hole mounting location is 50% stiffer. Well, that translates into a 750 lbs effective rate which would be the same effective rate as running a 40.5mm bar.

Obviously these percentages and numbers are not correct vs. the real 27mm-29mm bar, but I wanted to explain how the measurements became rated in mm as opposed to effective rates. The better suspension companies will tell you what the percentage increase is, what the effective rates are, and what the equivalent bar diameter would be as well...If not, the math is relatively simple given a percentage and base effective rate.

Does this help make it clear as mud? Swaybar math can be really fuzzy since I've run across manufacturers (*cough* Perrin *cough*) that don't do it right...I actually went into some math on this very issue in my Evo member journal if you'd like to see more concrete numbers behind how diameters are arrived at on adjustable bars.

[DaveSTi]

Here's a link to real examples for you, Bryan.

http://www.tristatetuners.com/forum/...&postcount=324

[TROLL]

cool, thanks for the response. glad to be able to confirm the swaybar 'myth'

[Khellen]

Very interesting facts. Guess I'll just have to stay soft in the future.

[DaveSTi]

Originally Posted by Khellen

Very interesting facts. Guess I'll just have to say soft in the future.

Honestly, it doesn't matter how you say it, it's all based off of effective rate.

That's all a swaybar does.

[jgartland]

Great read. Thanks for the write up!

[JB'sLGT]

fixed

Originally Posted by DaveSTi

Oh, I won't disagree with you at all because you are 100% correct!

The diameter of the bar is what drives the initial soft "setting" on bars. Like you stated, a Whiteline 27mm is 27mm in diameter. Here is where swaybar math gets fuzzy...

The increase in bar stiffness comes from the location of the mounting holes on the bar...closer to the bar, the stiffer it is. Now, how much stiffer are these holes? That is where the construction of the bar comes into play as well as the location of the mounting holes. This is explained in a percentage increase.

By using the known effective bar rate of 27mm (let's make this easy and say its 500 lbs of effective rate), Whiteline can say that the next hole mounting location is 50% stiffer. Well, that translates into a 750 lbs effective rate which would be the same effective rate as running a 40.5mm bar.

Obviously these percentages and numbers are not correct vs. the real 27mm-29mm bar, but I wanted to explain how the measurements became rated in mm as opposed to effective rates. The better suspension companies will tell you what the percentage increase is, what the effective rates are, and what the equivalent bar diameter would be as well...If not, the math is relatively simple given a percentage and base effective rate.

Does this help make it clear as mud? Swaybar math can be really fuzzy since I've run across manufacturers (*cough* Perrin *cough*) that don't do it right...I actually went into some math on this very issue in my Evo member journal if you'd like to see more concrete numbers behind how diameters are arrived at on adjustable bars.

[DaveSTi]

Originally Posted by JB'sLGT

fixed

Thanks...had a mental block on that.

[Khellen]

Yep, still learning tons of stuff from this post. haha

[jesse096]

I like the dialog in some of your lines haha!

Good write up! If I get a Subie, I'll deffinatly refer to this thread!

-Jesse