18x11/18x13 vs ACR 18x10/19x13 for track car

[Magnus_]

I've been reevaluating my setup for next year.

Currently I run 18x11 and 18x13 wheels on the car.

I noticed many track rats though run the ACR wheels.

I like to bring at least 3 full sets of wheels/tires to the track. (R100, R6 and a wet tire I haven't decided on yet)

Am I better off switching to the ACR sizes or sticking with the 18x11 and 18x13 setup?

I'm PLANNING on doing the entire NARRA schedule in 2013.

Thanks.

- Keith

 

[VJR3]

NARRA is a great schedule to run, I hope to do the same next year.

Stick with the 18's especially the 11 inchers up front, they run 315's no problems, even 335's if u want to get nuts

Comp coupes run 18's all the way around............19's tires are alot more money then the 18's

If you can swing 3 sets of tires I would run R6's and A6's...use the A's when you want to blitz off your hot time for time trials............wets not a biggie, your not going to want to run a viper in the rain......the R6's and A6's do great on a damp track, no standing water though

 

[Boxer12]

I would get a set of 19's, esp since you are running the same (R) compound tires. Give yourself a higher 4th gear top speed option for the bigger tracks like Road America. Also, the Michelin slicks (ACR-X spec) are a couple seconds faster than Hoosiers for a lap or two. That is one reason most guys running 19's. Plan to buy a set a weekend for your qualifying lap if you really plan to be competitive.

PS-Last time I checked, you can't get R100 in 19" sizes. You will have to run Michelins, A6 or R6 on those 19" wheels.

 

[steve911]

18's in all 4 corners if you have the stock 5th and 6th gear trans ratios are the way to go. It pulls harder in the lower gears and allows you to use 5th (if you want) at Road America. Don't quote me on this exactly, but I believe that 335-18's on a 3.07 diff will net out to a 3.11 or 3.13 (something like that).

I ran A-6's and loved them. I now have some NOS Hoosier NARRA SPEC slicks that I just picked up from Hoosier that I can't wait to try. I have one set scuffed in and they seem way better the A-6's and R-6's that I have.

 

[redtanrt10]

Magnus, I'd stick with the 18's all around, the 11" front's work well with the 315's and for the rear the 345 35 18's are as tall as the 345 30 19's so the rear ratio doesn't change. (If you run the 335 18's the rear end goes to about 3:21). There are 5 or 6 ACR's running consistently here in SoCal, vast majority (if not all) are on 18" foreglines and OZ's. good luck, Mike

 

[challenger&viper]

,,,,, by mistake

 

[Magnus_]

Lots of good info. Thanks everyone!

I was hopping to run hoosier tires for the contingency. I'm only planning to do TT1 next year and my plan was to warm up on the R6's and then switch to the R100's for the timed lap.

Looking forward.

 

[steve911]

What are you running for suspension in your car? Spring rates, sway bars etc? TT1 or TT2

I've been reevaluating my setup for next year.

Currently I run 18x11 and 18x13 wheels on the car.

I noticed many track rats though run the ACR wheels.

I like to bring at least 3 full sets of wheels/tires to the track. (R100, R6 and a wet tire I haven't decided on yet)

Am I better off switching to the ACR sizes or sticking with the 18x11 and 18x13 setup?

I'm PLANNING on doing the entire NARRA schedule in 2013.

Thanks.

- Keith

 

[DrumrBoy]

Give yourself a higher 4th gear top speed option for the bigger tracks

Good point. Its very nice to have that option......you can manage "effective ratio" for whatever your circumstance. There are plenty of times when you can pick up a few tenths by not shifting to third or fourth as well as 5th.

 

[Boxer12]

More info-As far as weights and measures goes, the 345/30/19 is about three quarter inch taller than a 345/35/18 (measured, not calculated) and 5 lbs lighter (in A6 rubber). The 19 has a lower sidewall, and I find it faster than the 18's (I have tried just about every Gen IV tire combo including R100's in 18" size (which is about 1 3/4 in shorter than a 19) except Michelins, but everyone says they are faster than a Hoosier A6 for one lap, one time). I have a set of 335/30/18's on the shelf and although I haven't run them on the Gen IV they measure about 1 1/2" less diameter than a 345/30/19.

Also, if you have stock tranny, you are at a disadvantage. I think 5th gear in the stock tranny is useless, and you will lose a lot at tracks like RA. You also might want to have a spare diff with gears for shorter tracks if you really want to be competitive. Just my experience.

 

[Magnus_]

What are you running for suspension in your car? Spring rates, sway bars etc? TT1 or TT2

Moton clubsports, 900/1300 springs.
Stock swaybars.
TT1

Boxer, I agree with you. 5'th gear is useless in the stock trans.

I only did one NARRA event this year, Road America. Now, granted I do have 5000+ miles on that track, My car was just barely broken out of the TT2 class into the TT1 class and I felt competitive enough to my satisfaction. I'm not looking to absolutely dominate here, but more so plan my purchases carefully for the setup that is a work in progress.

Point being, if the end-result with proper a proper trans/gear config for each track means 18x11/18x13 setup is superior than 18x10/19x13 (ACR), then I'd like to purchase additional wheels and new tires for that setup. I don't want to invest more into my wheel/tire setup when down the road I'll have to sell all 4 sets of wheels again for a new set.

Hope that makes sense.

 

[steve911]

Time to upgrade the sway bars. The stock gen 3 -4 swaybars arent really up to what you are going to ask them to do. If you dont want to do any fab work, the 1st gen Comp coupe sway bars were solid bars as opposed to the tubular ones in the street cars and slightly larger in diameter.

They made a heck of a difference in my car. Give Cory a call @Snakeoyl Products as I believe he has a set or two. there are other choices also each with varying amounts of fabrication required.

 

[Viper X]

More info-As far as weights and measures goes, the 345/30/19 is about three quarter inch taller than a 345/35/18 (measured, not calculated) and 5 lbs lighter (in A6 rubber). The 19 has a lower sidewall, and I find it faster than the 18's (I have tried just about every Gen IV tire combo including R100's in 18" size (which is about 1 3/4 in shorter than a 19) except Michelins, but everyone says they are faster than a Hoosier A6 for one lap, one time). I have a set of 335/30/18's on the shelf and although I haven't run them on the Gen IV they measure about 1 1/2" less diameter than a 345/30/19.

Also, if you have stock tranny, you are at a disadvantage. I think 5th gear in the stock tranny is useless, and you will lose a lot at tracks like RA. You also might want to have a spare diff with gears for shorter tracks if you really want to be competitive. Just my experience.

Check this link on Hoosier rears: http://www.tirerack.com/tires/tires.jsp?tireMake=Hoosier&tireModel=R6

The info above in red is incorrect on Hoosier R & A6 tires, per Tire Rack. The 345 x 30 x 19 rears are exactly the same height, i.e. 26.8 inches as the 345 x 35 x 18's. No difference.

The tread width is .3 wider for the 345 x 35 x 18 and it's a pound lighter than the 19 in the R6. The A6 is slightly different, i.e. the 18 is only .2 inches wider and the two tire types weigh the same. Their is no advantage running a 19 inch rear tire, unless you want to pay about $40 more per tire, and the 19 x 13 inch rear wheel is heavier than the 18 x 13 inch rear wheel with most brands.

You will get a shorter sidewall with the 19 inch rear tire which is less forgiving, IMHO, i.e. less sticky than the 18.

Try them both, I have, then you decide which one feels better for you.

On the R100s, I've also tried them and the rears are very short for the Gen IV ACR that I drive, and my ACR is pretty low. Trying to practice with the the taller R6s, then switch to R100's may make you slower as they will change your shift points, which, depending on the track, might cost you some time.

You many want to practice with R6's on Friday, then run A6's Saturday morning for your best lap time. A6's don't take the heat nearly as well as the R6's do, so be careful with them on a warm afternoon or just switch back to the R6's.

On the 5th gear ratio subject, there are very few tracks where you will need 5th gear. RA may be one of them, never run there. My 09 ACR easily does 160 mph at the top of fourth gear and this is enough most of the time, even on "Roval" tracks. I do shift to 5th at the end of the front straight at Auto Club Speedway, Fontana, CA when I'm just running laps, but I don't really have to. I just want my engine to live longer. If I were on a "hot lap" for time, I' stay in 4th.

The best bet on this subject is to change to the 2010 revised 5th gear.

Good luck,

Dan

 

[Viper X]

Time to upgrade the sway bars. The stock gen 3 -4 swaybars arent really up to what you are going to ask them to do. If you dont want to do any fab work, the 1st gen Comp coupe sway bars were solid bars as opposed to the tubular ones in the street cars and slightly larger in diameter.

They made a heck of a difference in my car. Give Cory a call @Snakeoyl Products as I believe he has a set or two. there are other choices also each with varying amounts of fabrication required.

Sway bars do make a difference. The OE stock sway bars in the Gen IV ACR are solid and are an exact fit for the hollow sway bars in the Gen III cars, i.e. no fabrication necessary. Don't forget to upgrade the sway bar bushings from OE rubber to polyurethane. Archer Racing can supply these for you.

Good luck,

Dan

 

[Magnus_]

I guess here's my next question,

Why does the ACR-X come with 19's in back?

 

[Viper X]

I guess here's my next question,

Why does the ACR-X come with 19's in back?

Good question for Dodge / now SRT. Likely, price and availability were considerations. They likely had 100's of 19 inch rears being made, so making a few more or simply painting some was easy.

The Comp Coupe, their premier race car until lately, runs 18s at the rear.

What size tires is the new GTS R running out back? Don't know but would guess 18s.

There are many other questions regarding the ACR-X and its OE equipment. The most obvious to me would be: "Why did they chose the KW shocks when better racing shocks are available?"

The Comp Coupe came with Motons.

Why did Dodge chose American Racing Headers when the Comp Coupe team selected Belanger Headers?

The questions go on and as above, likely price and availability were the main factors in their decisions and sometimes ultimate performance, but not always. I'm hoping this will change under the SRT banner and more focus for Viper will be on performance. In fact, I'm betting it will!

Dan

 

[Magnus_]

Dan, you're a plethora of information. Thank you very much!

- Keith

 

[Max]

Hi all,

what would be a good wheel size for the track for a 2010 ACR?

I can't find any spare ACR wheels anywhere. What specs should I look for when I search for alternative wheels?

I will most likely put slicks on those wheels.

Thank you very much,

Max

 

[Magnus_]

JonB@PartsRack probably has ACR wheels for sale, and can also set you up with 18x11/18x13 wheels as well, like a set of OZ wheels.

 

[steve911]

Sway bars do make a difference. The OE stock sway bars in the Gen IV ACR are solid and are an exact fit for the hollow sway bars in the Gen III cars, i.e. no fabrication necessary. Don't forget to upgrade the sway bar bushings from OE rubber to polyurethane. Archer Racing can supply these for you.

Good luck,

Dan

Actually the first generation of comp coupes came with larger solid bars than the Gen 4 does now. Its pretty amazing I think, how heavy each bar is, but they sure work... They also came with adjustable end links to help chassis set up.

 

[steve911]

JonB@PartsRack probably has ACR wheels for sale, and can also set you up with 18x11/18x13 wheels as well, like a set of OZ wheels.

I run the black OZ 18's when I am on slicks. Strong and lightweight to boot.

 

[Viper X]

I run the black OZ 18's when I am on slicks. Strong and lightweight to boot.

The OZ wheels in 18 x 11 and 18 x 13 seem to be the hot ticket for track wheels right now. Call Jon B at Partsrack.

You can buy adjustable sway bar end links for the Gen III and Gen IV Viper from Dodge Motorsports South. Talk with Tom Francis.

Good luck,

Dan

 

[steve911]

The OZ wheels in 18 x 11 and 18 x 13 seem to be the hot ticket for track wheels right now. Call Jon B at Partsrack.

You can buy adjustable sway bar end links for the Gen III and Gen IV Viper from Dodge Motorsports South. Talk with Tom Francis.

Good luck,

Dan

The end links from dodge south require the tapered holes in the sway bar to be drilled out. Once you do that, you wont be able to go back to the stock ones as they need a tapered hole to work.

The adjustable ones from SnakeOyl still retain the tapered ends that go through the bar, and are just as strong as the ones from Dodge. I have a set of each, Dodge South on my '04 and SnakeOyl's on my '06 coupe.

Steve A.

 

[JG01]

Try the Michelins -

I ran the Michelin slicks last Sunday for 50 laps at the 2.75 mile Nola track. They are 3 seconds faster than the R6 setup. The big difference is your ability to hold more speed through the corners. The tires still look good enough for another 50 after swapping sides. The Michelins cost more but last longer too. I did see a slight fall off in times after 20 but they came back hot around lap 40. Again, 3 seconds faster.

 

[Viper X]

The end links from dodge south require the tapered holes in the sway bar to be drilled out. Once you do that, you wont be able to go back to the stock ones as they need a tapered hole to work.

The adjustable ones from SnakeOyl still retain the tapered ends that go through the bar, and are just as strong as the ones from Dodge. I have a set of each, Dodge South on my '04 and SnakeOyl's on my '06 coupe.

Steve A.

I've installed several sets of the DMS south adjustable end links on two 09 ACRs and no drilling of the sway bar ends was necessary. Just use the correctly sized bolts.

 

[Viper X]

Try the Michelins -

I ran the Michelin slicks last Sunday for 50 laps at the 2.75 mile Nola track. They are 3 seconds faster than the R6 setup. The big difference is your ability to hold more speed through the corners. The tires still look good enough for another 50 after swapping sides. The Michelins cost more but last longer too. I did see a slight fall off in times after 20 but they came back hot around lap 40. Again, 3 seconds faster.

The Michelin slicks, used by the Viper Cup series, are very fast when new, are more expensive than the R6s and wear out twice as fast as the R6s, so life cycle cost is very high. If you want more speed for a short time, try the A6s. They are almost as sticky as the Michelins, cost less and last longer.

JG01, be careful then they cord as one lap will feel OK, then they'll cord and grip goes away with little warn.

 

[Max]

Thanks all for your feedback... O.Z. seems like the way to go.