STX Weight

[murph]

Ever wonder what a ZHP can get down to in SCCA Solo STX trim?

As part of my suspension build weekend I corner weighted the car. With essentially all the weight-saving allowances of STX, almost 1/4 tank more gas than I'd run in competition, and a 2003 non-sunroof ZHP, it weighed in at 3,088 lbs. So without the extra gas, that's somewhere around 3,065 lbs. With a lighter exhaust, dumping the fogs and HIDs, and lightweight brakes it could probably be in the 3,025 lb range.

Hope that's helpful for any of you interested in trying STX. Hopefully later this season I'll have some results as to whether the ZHP can be competitive. I think it will.

[bcleaver]

Hey Matt, do you know off-hand the race weight of some of the competition: wrx, e36, rx-8?

[M0nk3y]

Removing Headlights and Fogs aren't allowed in STX.

The ZHP can be very competitive if you have good tires, suspension, and sway bars....and a good driver.

When we had a 330ci with Hankook R-S3s run (he only ran once). He put down a good enough time to get third in STX (0.4 seconds behind a Impreza, and 0.1 seconds behing a RX-8)

[az3579]

Hey Matt, do you know off-hand the race weight of some of the competition: wrx, e36, rx-8?

I once drove a C-Stock fully prepared RX-8 and it weighed in the 2900's.

[Mike V]

I autocrossed my zhp for the first time this past Sunday. The lack of an LSD in this car is very frustrating. With DSC completely off, the unloaded inner wheel was spinning like crazy. With the electronic "diff" on, it was too intrusive. I've been autocrossing for 9 years and this is only my 2nd time running a car with traction control. I forgot to turn it off at all during the first run and that sucked. My 2nd run was nearly 2 seconds faster. :)

[M0nk3y]

I autocrossed my zhp for the first time this past Sunday. The lack of an LSD in this car is very frustrating. With DSC completely off, the unloaded inner wheel was spinning like crazy. With the electronic "diff" on, it was too intrusive. I've been autocrossing for 9 years and this is only my 2nd time running a car with traction control. I forgot to turn it off at all during the first run and that sucked. My 2nd run was nearly 2 seconds faster. :)

TC on any BMW is a huge walking cane.

[danewilson77]

TC on any BMW is a huge walking cane.

I want an lsd....:shifty

Droid! Srs Legitness!

[az3579]

TC on any BMW is a huge walking cane.

This. I live with it; turn the TC off (completely). You won't be going as fast as you want with it on, no matter how much better you think it is with it...

[Mike V]

This. I live with it; turn the TC off (completely). You won't be going as fast as you want with it on, no matter how much better you think it is with it...

If that's how my post sounded, that's not what I meant. I did go quicker in raw time with the DSC in the electronic diff mode (or whatever it's called) but that was just because I had a cleaner run. I was happy with my time with the 2nd run (DSC completely off), so I was just experimenting with the diff mode on that 4th run for the heck of it. I didn't like it because it was still too intrusive (you can really tell it uses the brakes for the 'diff' function). Either way, it was frustrating autoxing this car without an lsd (old PS1s didn't help either though) but DSC completely off is quicker, even though the inside rear will spin.

[UncleSmitty]

I'm still amazed that my 21-year-old e34 525i pulls better out of the corners than the ZHP... bleh. Thanks very much BMW.

Iso quality LSD at a reasonable price!

[az3579]

If that's how my post sounded, that's not what I meant. I did go quicker in raw time with the DSC in the electronic diff mode (or whatever it's called) but that was just because I had a cleaner run. I was happy with my time with the 2nd run (DSC completely off), so I was just experimenting with the diff mode on that 4th run for the heck of it. I didn't like it because it was still too intrusive (you can really tell it uses the brakes for the 'diff' function). Either way, it was frustrating autoxing this car without an lsd (old PS1s didn't help either though) but DSC completely off is quicker, even though the inside rear will spin.

My bad; though you meant that you were faster with it on. lol

The TC/DSC system doesn't do anything with the diff, unfortunately. Even if it was some sort of electronic diff, I think that would be better than the straight-up open mechanical diff that we have in our cars. The TC/DSC system as far as I know it is pretty much automatic and electronic control of the brakes on all four corners, not much more. I think someone once posted up how the ASC+T/DSC system works; have to find it.

[mimalmo]

What did PEI330CI on E46 Fanatics get his car down to with all of his weight reduction?

[danewilson77]

What did PEI330CI on E46 Fanatics get his car down to with all of his weight reduction?

Good question.

http://forums.bimmerforums.com/forum/showthread.php?t=961380

[MasterC17]

If I remember correctly PEI330Ci was down around 2700-2750lbs. It's not too difficult to get to 3000lbs if you're willing to give up some amenities. That's my goal.

While DSC is definitely very intrusive I don't mind TC too much, not sure if I'm faster with or without it on. The name of the game is to be smooth - something I need to work on.

[az3579]

If I remember correctly PEI330Ci was down around 2700-2750lbs. It's not too difficult to get to 3000lbs if you're willing to give up some amenities. That's my goal.


Well yeah, but to get down to that weight, I'm pretty sure that car is unbearable to drive on the street. Heck, I'd be hard pressed to believe it's even street legal...
The only way I see of reducing weight by about 600 pounds is to do some massive work to the body and only putting in the bare essentials to make the car work.

[bcleaver]

If I remember correctly PEI330Ci was down around 2700-2750lbs. It's not too difficult to get to 3000lbs if you're willing to give up some amenities. That's my goal.



Depending on what motorsport/class you're setting up for sub 3000lbs is very doable. However, as the thread is titled, getting below 3000lbs for scca STX class is a real challenge. The OP's car has damn near every weight allowance possible and he's just over still

[MasterC17]

Depending on what motorsport/class you're setting up for sub 3000lbs is very doable. However, as the thread is titled, getting below 3000lbs for scca STX class is a real challenge. The OP's car has damn near every weight allowance possible and he's just over still

I was referring to just generally getting below 3000 lbs not in a specific class - I know in STX it would be much harder.

[M0nk3y]

Depending on what motorsport/class you're setting up for sub 3000lbs is very doable. However, as the thread is titled, getting below 3000lbs for scca STX class is a real challenge. The OP's car has damn near every weight allowance possible and he's just over still

In STX doing and weight modifications isn't legal.

[murph]

Removing Headlights and Fogs aren't allowed in STX.

Removing foglights is legal in 2011, that changed with the new wing rule. I wouldn't remove the headlights, but I may downgrade from HIDs to the Halogens. Gotta pull the HIDs and weigh them. They're nice, so if it's only a pound or two I'll probably leave them on.

[murph]

Hey Matt, do you know off-hand the race weight of some of the competition: wrx, e36, rx-8?

The E36s are around 2,850, (328 has a non-sunroof option that 325 does not, which seems to offset the motor weight difference) I think the RX-8s are around 2,750, and the WRXs are just under 3,000 lbs, though keep in mind they're also limited to 245mm tires. Terry is giving it a go in his 3,600 lb 2011 Mustang, but I don't think that pig will fly. Jason Rhoades is building a '69 Camero, which sounds like it might be somewhere around 2,700 lbs, and have lots of torque, but may really struggle suspension-wise.

[az3579]

The E36s are around 2,850, (328 has a non-sunroof option that 325 does not, which seems to offset the motor weight difference) I think the RX-8s are around 2,750, and the WRXs are just under 3,000 lbs, though keep in mind they're also limited to 245mm tires. Terry is giving it a go in his 3,600 lb 2011 Mustang, but I don't think that pig will fly. Jason Rhoades is building a '69 Camero, which sounds like it might be somewhere around 2,700 lbs, and have lots of torque, but may really struggle suspension-wise.

I'm almost certain E36's are a lot heavier than 2800 lbs. I once saw a scale show an E36 M3 at a hair over 3000lbs. Heck, my E30, which is more basic, was a few lbs shy of 2800.

Sent from my DROIDX

[bcleaver]

In STX doing and weight modifications isn't legal.

I guess it depends on how you define 'weight modifications'. You can swap out stock exhaust for custom (###), lightweight battery (#), seats (##), etc.

[M0nk3y]

Removing foglights is legal in 2011, that changed with the new wing rule. I wouldn't remove the headlights, but I may downgrade from HIDs to the Halogens. Gotta pull the HIDs and weigh them. They're nice, so if it's only a pound or two I'll probably leave them on.

Ah, Good Call


I guess it depends on how you define 'weight modifications'. You can swap out stock exhaust for custom (###), lightweight battery (#), seats (##), etc.

Exhaust is allowed, along with battery. Once you touch the seats it's a no-go I'm pretty sure and you change classes

[az3579]

Exhaust is allowed, along with battery. Once you touch the seats it's a no-go I'm pretty sure and you change classes

You can change seats. The seats have to be fully upholstered and there are a couple of other guidelines I can't remember at the moment.

Sent from my DROIDX

[murph]

I'm almost certain E36's are a lot heavier than 2800 lbs. I once saw a scale show an E36 M3 at a hair over 3000lbs. Heck, my E30, which is more basic, was a few lbs shy of 2800.

I've seen the top STX cars on the scales myself. The M3s weigh a lot more than the non-Ms, the lightest of those are in the mid to upper 2900's, which is part of why some say they wouldn't be overdogs in STX. (I respectfully disagree)

[M0nk3y]

I've seen the top STX cars on the scales myself. The M3s weigh a lot more than the non-Ms, the lightest of those are in the mid to upper 2900's, which is part of why some say they wouldn't be overdogs in STX. (I respectfully disagree)

IMO M3s should be thrown into STX. They get murdered in STU by the 4 bangers.

[bcleaver]

IMO M3s should be thrown into STX. They get murdered in STU by the 4 bangers.

It's true that M3's don't have a great class to play in, but I think they would be overdogs in STX. STX is a great class now with a lot of variety in competition between the WRX, RX-8, 3 series and civics. Putting a car in there that would probably dominate, just to give the M3 drivers a place to play doesn't make sense to me.

[spencers]

I recall seeing notes from SCCA that the M3 is being reclassed for next year

[M0nk3y]

I recall seeing notes from SCCA that the M3 is being reclassed for next year

I hope they do.

I hope the M Coupes can also get a ST Class.

[spencers]

I hope they do.

I hope the M Coupes can also get a ST Class.

Eh, looks like it's CSP. See page 7:
http://www.scca.com/documents/2011%20Tech/2012%20Solo%20Rules%20Proposals%204-25-2011.pdf

Appears S2k will be the biggest competition.

[M0nk3y]

Eh, looks like it's CSP. See page 7:
http://www.scca.com/documents/2011%20Tech/2012%20Solo%20Rules%20Proposals%204-25-2011.pdf

Appears S2k will be the biggest competition.

...Still Stupid.

There should at least be a ST class for cars that can't class in the already predefined classes. I don't want to run against people against slicks.

Of course, I still do it for fun...but I always have the other side of me who wants to go up against a car with similar characteristics...and beat them.

(Like in STX. I was always neck and neck with another E46 and a Cobalt)

[murph]

The non-M are legal for STR, and still plenty fun, why didn't you pick up one of those? There are a million car choices out there, most of them aren't going to be competitive in the specific autocross category you'd like to compete in.

[Mike V]

...Still Stupid.

There should at least be a ST class for cars that can't class in the already predefined classes. I don't want to run against people against slicks.

Of course, I still do it for fun...but I always have the other side of me who wants to go up against a car with similar characteristics...and beat them.

(Like in STX. I was always neck and neck with another E46 and a Cobalt)

Does your region do a PAX'd street tire class? KC region started doing separate street tire and novice classes this year. They are both ranked by PAX. An additional PAX is applied to give the driver an idea how he does overall (since the PAX index assumes that the car is on R-comps).

[M0nk3y]

Does your region do a PAX'd street tire class? KC region started doing separate street tire and novice classes this year. They are both ranked by PAX. An additional PAX is applied to give the driver an idea how he does overall (since the PAX index assumes that the car is on R-comps).

One region around here does. I did that and I came out first in PAX. Absolutely murdered the 3 E36 Ms that were in it as well...pretty enjoying.

The region I go to often does not.

[zhp43867]

What weight reduction is permitted in STX? I am having a hell of a time trying to decipher the SCCA rules.

[murph]

Front seats, wheels, exhaust, headers, shocks, springs, swaybars, battery, intake can all be lighter than factory, then there is getting down to minimal options, like no-sunroof, halogen headlights.