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Javelin
Javelin GRM+ Memberand MegaDork
8/20/18 11:13 p.m.

Dad couldn't sell his Cobalt SS/SC and I've been looking for an S/ST-class car to build for autocross because being stuck in CAMC with a foxbody is annoying. Perusing all of the SCCA Solo rules I noticed that although the SS/SC is in the same ST/SP/Mod classes as it's much better younger sibling, the SS/TC, it is classified different in Street. The SS/TC has to play with really good cars in DS, the SS/SC is all the way down in GS! GS has been dominated by the Focus ST, but the SS/SC ran a better C&D Lightning Lap (and with 2006 tires versus 2014 tires...) and is lighter by almost 400lbs depending on trim. With a factory Quaife LSD and a shorter wheelbase, it should theoretically out-turn the FoST. GM is notorious for bottling up HP with the exhaust system, so a cat-back should help. I'm not a good enough driver to even think about going to Nationals, but this could be a Regionally competitive car. Thoughts?

CyberEric
CyberEric HalfDork
8/20/18 11:25 p.m.

Color me interested. 

What are stock rim widths? Just looked, the SC car makes 205 hp, pretty big discrepancy to the ST, but if it can fit the same tire and is really 400lbs lighter, It might offset the power difference.

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 12:21 a.m.

In reply to CyberEric :

As far as I can figure out, the SS/SC is a 17x7 205/50R17 or an 18x7 with 215/45R18. The FoST is 18x7 with 235/40R18. SS/SC is 2991 lbs curb weight on a 103" wheelbase and the FoST is 3248 lbs on a 104.3" wheelbase. So 250 lbs, not 400 lbs, but still significant. I imagine popular equipment will vary that greatly. So the SS/SC is 14.6 lbs/hp stock and the FoST is 13.0 lbs/hp. 

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 12:38 a.m.

In reply to CyberEric :

If I'm reading the Solo rules correctly, Street now has unlimited tire size as long as it's 200TW and fits on the stock rim width, and is +/- 1" in rim diameter. I can go 16"-19" on the SS/SC and even run different front/rear configurations. Hmmm.

Pete Gossett
Pete Gossett GRM+ Memberand MegaDork
8/21/18 5:30 a.m.

In reply to Javelin :

How much front camber can you get within Street rules?

Ian F
Ian F MegaDork
8/21/18 5:31 a.m.

In reply to Javelin :

That is correct. Essentially carry-over text from the "R-Comp" era (except the added diameter variation).  However, unlike Hoosiers, 200TW tires don't like being pinched, so squeezing more tire onto a 7" rim will only serve to lighten your wallet as far as performance improvements go. Thus a 205 or maybe a 215 is about all you can effectively use.

Pete Gossett said:

In reply to Javelin :

How much front camber can you get within Street rules?

Whatever is factory or dealer adjustable through either OEM parts or sometimes camber bolts.

gumby
gumby GRM+ Memberand Reader
8/21/18 6:21 a.m.

The tire is gonna handicap your effort. FoST oem is 18x8 not 7. Many S classed FoST are wearing 17x8's with 255 tires.

MINIzguy
MINIzguy HalfDork
8/21/18 7:17 a.m.

You can get around -2° camber once you grind the strut, factory alignment procedure too. Can't do camber bolts. You should probably do 225/45/17 all around, which is the same size as the FRS/BRZ so tires should be cheaper. Throw on a rear sway bar, everybody talks about the Powell bar, and some decent shocks and it should be fun.

I had a blast with my bone stock SS/TC on all-seasons. I've given it hard thought to make mine a D street car next season, as long as the winter doesn't kill it. It'll follow the same recipe.

Dave M
Dave M None
8/21/18 7:53 a.m.

My Solstice shares a lot with the Cobalt SS....and it's a blast. The Ecotec has a lot of untapped power potential to say the least. Go for it!

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 9:21 a.m.

In reply to MINIzguy :

Thank you!

NickD
NickD UberDork
8/21/18 10:07 a.m.

Another advantage the Cobalt SS has over the FoST, is that the CSS/SC has an actual mechanical limited-slip, vs the FoSTs ABS-style system. On longer courses, you won't be punishing the brakes as much.

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 10:56 a.m.
Javelin said:

In reply to CyberEric :

If I'm reading the Solo rules correctly, Street now has unlimited tire size as long as it's 200TW and fits on the stock rim width, and is +/- 1" in rim diameter. I can go 16"-19" on the SS/SC and even run different front/rear configurations. Hmmm.

My Focus ST is my 4nd Street class car and 5th car specifically bought for AutoX. I've spent a lot of time reading the rules and asking the right people questions. 

You're reading the rules mostly correct. 

if you want to run the LSD... you'll be working with whatever wheel size came on that option package. or if multiple options were available, you have to choose 1. so if 17's or 18's was available, you have to run wheel sizes +/- 1 inch of 1 diameter. you can't chose both.. 

also, if the option package with the LSD involved any other parts, spoiler/seats, etc. You have you install the full package to be legal. 

now back to the numbers, as Gumby Said the Focus wears 18x8's and almost everyone runs 17x8's nationally so you're at a large disadvantage there. 

I'm running 245's for nationals, but a lot of the class does run 255's.
 

MINIzguy said:

You can get around -2° camber once you grind the strut, factory alignment procedure too. Can't do camber bolts. You should probably do 225/45/17 all around, which is the same size as the FRS/BRZ so tires should be cheaper. Throw on a rear sway bar, everybody talks about the Powell bar, and some decent shocks and it should be fun.

Now it sounds like Chevy did give you one advantage if there is indeed a TSB allowing for the enlargement of strut holes to get negative Camber. You would need to be able to prove this for national competition. 

Now the Focus has been running the class the past few years, but the GTi with the updates a few years ago has become a popular alternative, although with a only 7.5 inch wheel. 

This year the 2018 Civic Si has become the new hot contender. almost all the people who bought G street cars in the past 12 months bought Civic Si's. WIth about a degree of negative camber and a real diff people seem to really like it. 

The Curb weights are also a bit misleading... We've got a SCCA G Street Solo Group on Facebook and people have been openly sharing weights and the ST built to the rules(spare tire removed, which is 50 lbs by itself, exhaust with no muffler and thinner tubing from the catalytic converter back and downsized wheels and a 1/4 tank of gas) race weight is down at 3050 lbs. the Civics are around 2800 flat and the GTi's are 3100+. 

So the civic's have basically all your weight advantage, have a real diff and get camber, but have a full inch more tire than you with their 17x8 rims.

Now, i'm not saying don't build the car, but definitely understand that you're going down a path that's not what is considered to be a recipe for success at the national level. 
I'm the first to say it's better to be at your local autox in an uncompetitive car, than at home not driving. But I definitely want you to be evaluating this build with eyes wide open. 

Now, While the 200TW tire's don't "like" pinch as the Hoosiers did as Ian F says, they still work very well while pinched and it's the popular opinion of most people is to pinch tires at a national level. Pretty much all of G street pinches 255/40R17 on a 17x8 if they can afford to. 

E street is Pinching 225/45R15's on 15x6's of the 99/2000 miatas or the 15x6 15x7 stagger of the MR2 Spyders. 


EDIT: added quoting because I was making MiniZ crazy with my replies only. 

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 11:01 a.m.

In reply to spacecadet :

Thank you. The LSD was a stand-alone option in the SS/SC cars. The wheels were also stand-alone, but thank you for clarifying that I have to stick with one of them. It was pointed out to me somewhere else that the BRZ/FRS/86 run a 225/45/17 successfully on a 17x7 and that they were an affordable price because of the popularity.

MINIzguy
MINIzguy HalfDork
8/21/18 11:13 a.m.

I pointed out the tire sizes a few posts up!

Anyway, looking at the numbers, I don't thing the SS/SC will do that well against the FOST because of the power and tire disadvantage. I've never driven a FOST so I don't know how much better the Cobalt chassis is. I'll probably try again after this year to class the SS/TC in G street to play with the FOST/GTI/Si because on paper, they look to be comparable.

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 11:15 a.m.
Javelin said:

Dad couldn't sell his Cobalt SS/SC and I've been looking for an S/ST-class car to build for autocross because being stuck in CAMC with a foxbody is annoying. Perusing all of the SCCA Solo rules I noticed that although the SS/SC is in the same ST/SP/Mod classes as it's much better younger sibling, the SS/TC, it is classified different in Street. The SS/TC has to play with really good cars in DS, the SS/SC is all the way down in GS! GS has been dominated by the Focus ST, but the SS/SC ran a better C&D Lightning Lap (and with 2006 tires versus 2014 tires...) and is lighter by almost 400lbs depending on trim. With a factory Quaife LSD and a shorter wheelbase, it should theoretically out-turn the FoST. GM is notorious for bottling up HP with the exhaust system, so a cat-back should help. I'm not a good enough driver to even think about going to Nationals, but this could be a Regionally competitive car. Thoughts?

Also, did the Foxbody not just get an allowance to go to CAM-T? not that that's much consolation with the cars like the Dusold Designs Camaro now legal for CAM-T in 2018 with a custom aftermarket ABS system. 

 

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 11:17 a.m.
MINIzguy said:

I pointed out the tire sizes a few posts up!

Anyway, looking at the numbers, I don't thing the SS/SC will do that well against the FOST because of the power and tire disadvantage. I've never driven a FOST so I don't know how much better the Cobalt chassis is. I'll probably try again after this year to class the SS/TC in G street to play with the FOST/GTI/Si because on paper, they look to be comparable.

Yep, I saw your comment about the hole grinding as well, which was why I made the point to say he'd have to prove it. 

EDIT: added quoting because I was making MiniZ' crazy with my replies only. 

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 11:17 a.m.

In reply to MINIzguy :

Somewhere else apparently means your post! blush Sorry!  I know the FoST is more power and more tire, yet the SS/SC was quicker in the Lightning Lap and runs better 0-60 on 10-year-older technology tires. The big autocross equalizer though is the differential. The FoST is an e-diff that uses ABS and is notorious for killing brakes and the SS/SC has a mechanical Quaife unit.

The problem is the new Civic SI is also G Street. 3002 Lbs, 205HP, 18x8's, helical LSD, IRS. Still slower to 60 than the SS/SC but I imagine the chassis will have some advantages...

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 11:19 a.m.

 

Javelin said:

In reply to spacecadet :

Thank you. The LSD was a stand-alone option in the SS/SC cars. The wheels were also stand-alone, but thank you for clarifying that I have to stick with one of them. It was pointed out to me somewhere else that the BRZ/FRS/86 run a 225/45/17 successfully on a 17x7 and that they were an affordable price because of the popularity.

a quick google and wiki search says that's not the case, but again. if you have the documentation from Chevy to prove that, then you're good. also I heavily expanded my original comment, I hit post before i meant to. 

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 11:28 a.m.
MINIzguy said:

I pointed out the tire sizes a few posts up!

Anyway, looking at the numbers, I don't thing the SS/SC will do that well against the FOST because of the power and tire disadvantage. I've never driven a FOST so I don't know how much better the Cobalt chassis is. I'll probably try again after this year to class the SS/TC in G street to play with the FOST/GTI/Si because on paper, they look to be comparable.

Sorry, I should have mentioned you directly when talking about you comment on both Camber and the Twin's Tire sizes. 

spacecadet
spacecadet GRM+ Memberand New Reader
8/21/18 11:34 a.m.
Javelin said:

In reply to MINIzguy :

Somewhere else apparently means your post! blush Sorry!  I know the FoST is more power and more tire, yet the SS/SC was quicker in the Lightning Lap and runs better 0-60 on 10-year-older technology tires. The big autocross equalizer though is the differential. The FoST is an e-diff that uses ABS and is notorious for killing brakes and the SS/SC has a mechanical Quaife unit.

The problem is the new Civic SI is also G Street. 3002 Lbs, 205HP, 18x8's, helical LSD, IRS. Still slower to 60 than the SS/SC but I imagine the chassis will have some advantages...

Like I said above, in my accidental ninja edit, it's the new popular choice.

But, it's not my favorite. I'm a big fan of the Focus, I LOVE the 270 LB ft of torque and 252HP. I drove the civic last fall and thought it was great, but loved the power of the focus on the street and couldn't pay thousands more for a Civic Si, I paid $20k for my ST1 Focus ST when I bought it in December. I drove the Civic Si again about a month ago just to see if I felt any different after owning a focus for 7 months and I still am a bigger fan of the Focus. The focus is not without fault, but when I found out the Civic guys are having to do a pedal dance I was completely turned off to the car. 

MINIzguy
MINIzguy HalfDork
8/21/18 12:13 p.m.
spacecadet said:

Like I said above, in my accidental ninja edit, it's the new popular choice.

But, it's not my favorite. I'm a big fan of the Focus, I LOVE the 270 LB ft of torque and 252HP. I drove the civic last fall and thought it was great, but loved the power of the focus on the street and couldn't pay thousands more for a Civic Si, I paid $20k for my ST1 Focus ST when I bought it in December. I drove the Civic Si again about a month ago just to see if I felt any different after owning a focus for 7 months and I still am a bigger fan of the Focus. The focus is not without fault, but when I found out the Civic guys are having to do a pedal dance I was completely turned off to the car. 

Ahh all the quoting and responses have me confused reading this thread. There's plenty of documentation online for the strut grind, I have it bookmarked on a forum and also have it on All Data.

I've thought of going into G street a few times. I never really liked the FOST I sat in with the Recaros, but I've never driven one either. I test drove a Civic Si and it felt slow, but it was a nice car to be in. I really gotta find somebody to let me snag a co-drive in both cars to see if I like it over the Cobalt. I wish my current car was eligible but SCCA thinks it should play with the Camaro and CTR. There is a Cobalt SS/TC going to nats this year, so I'll be sure to pry his brain on what he thinks. I'll be there this year, most likely in my STX BMW.

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 12:19 p.m.

In reply to spacecadet :

I have an SN95, which is a fat foxbody, and it's stuck in CAMC.

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 12:23 p.m.

In reply to MINIzguy :

Please don't put the SS/TC in GS! That car is world's better than the SC and on paper should stick it to the FoST and Civic Si.

MINIzguy
MINIzguy HalfDork
8/21/18 12:28 p.m.
Javelin said:

In reply to MINIzguy :

Please don't put the SS/TC in GS! That car is world's better than the SC and on paper should stick it to the FoST and Civic Si.

"On paper"

There's a NNJR SCCA guy that wants the SS/SC in HS cheeky When the stars align and both cars get reclassed would be a joyous day. I'd buy an SS/SC in a heartbeat and run in both classes.

Javelin
Javelin GRM+ Memberand MegaDork
8/21/18 12:31 p.m.

In reply to MINIzguy :

I would totally run Hooptie Street in the SC!

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