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Discussion Starter · #1 ·
I just bought a 2005 300c rwd I would like to make it a back up race car. I am thinking a torque converter a tune and slicks would make it run 12.90 ish I can not find any racing tires for a stock rim what do you guys use and what is the best tuner for the car. Any advice on what actually is worth the money would be great too. Has anybody ever tried to put 15" rims on the back so they could use a real slick also?
 

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Discussion Starter · #2 ·
I would love advice on what brand converter,tuner, rims back spacing and size, tires, to get and any other general racing tips for this car. I am very experienced drag racer but this is my first newer model chrysler.
 

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I'm rather slow ,but I don't think those mods will get you 12.9's. i would more than likely think low 13's. Paramount-FTI tc for the win. With stock bits I would think a 2800 stall would be nice. B eal careful with slicks and DR's on your stock half shafts. They will snap with a good hook.
the best tuner hands down for ou cars is the Diablosprt. they are now made i 2 varieties. The in-une and the trinity. They both have the same tunes but the trinity is more feature packed. You might find and old predator out there(diablosport's original tuner) but if use you must find one that is un-married from the previous car
 
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Couldn't agree more with the above... He's even being generous on low 13's with just those mods.

Your not going to break into the 12's with a converter, tune and a set of slicks as your only mods. I really hate to be the bearer of bad news... Also a set of true 'slicks' on the back of a stock 5.7 diff will leave an axle at the line the first time you flash the converter past 2800 on a launch...

If you truly want to run 12's in a 5.7 then your going to need a cam... Period. The stock car just doesn't have enough to get you there. Low 13's on full bolt ons but to get through into the 12's with full bolt ons will require either some hella short gears and a stall, or a cam... But just a converter and slicks won't get you there...

Precision Industries converters are great, lock well, creep well, stall perfectly... You can get certain 16" wheels over stock 5.7 rear brakes but not all.. 17-18" are perfect. If you run drag radials on stock gearing and axles with a converter your on borrowed time... If you run slicks you may get one or two passes. I recommend an r/t axle upgrade or a swap to a whole 09 or newer chally diff and axles...



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Yamabob really said it right in all cases, just wanted to back that up by saying the stock half shafts aren't all that great so I would suggest switching them out. Best thing to do is look up the Getrag in the gear you prefer. And you have some work to do besides the items you mentioned if you want to get into the 12's. I have 150 shot ZEX, Trinity and the basics (exhaust, intake) and don't come near the 12.9 area. However, a lot of that is also the fact that my wheels rob a lot of power from me. But still, I doubt those numbers are in my sight even with slicks. Diablosport is the best solution for your tuning needs.
 

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I would highly recommend you contact this company for a converter. I have used a number of them on my '00 Camaro when I was racing, and they make the best.

www.converter.cc
 

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Cam, intake, headers, exhaust, 2800 stall converter, Paramount transmission build, Getrag or DSS 3rd member kit with axles (3.73:1), consider spraying.

This is a big, heavy, 4 door sedan and 12.9x is a bit faster than what this car will do with just your planned mods.

16" aftermarket or 18" stock wheels with an 15 - 18 mm offset are recommended. If you go wider than stock, change the offset or you'll rub. You'll want to measure the inside diameter of the wheel to insure it clears the brakes if you go with a 16" wheel.
 

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Basically look at the mods in my sig... Remove nitrous, rear diff and stall and you have a 12.7-12.9 car... ;) Cam only I just broke into the 12's... No cam I was 13.2-13.4... :)

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I just bought a 2005 300c rwd I would like to make it a back up race car. I am thinking a torque converter a tune and slicks would make it run 12.90 ish I can not find any racing tires for a stock rim what do you guys use and what is the best tuner for the car. Any advice on what actually is worth the money would be great too. Has anybody ever tried to put 15" rims on the back so they could use a real slick also?
Read this---> https://www.google.com/url?sa=t&sou...gQFjAA&usg=AFQjCNHyE0Cw94dconwiZO3Lh0z4zcrgKg

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I think everyone has covered everything fairly well. One more HUGE variable is weight reduction. If all you want to use it for is a back up race car, then remove weight (passenger seat, rear seat, stereo/radio, spare tire, etc., etc.). You can most certainly gain a few tenths just by stripping her down.

Also, once you get your DiabloSport tuner, install a 180 T-Stat and change your fan settings. Mine was running around 218-220 degrees at the track and now runs around 190-195. That alone is 2-3 tenths in the quarter mile.

GL! :fing02:
 

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Discussion Starter · #11 ·
You guys are great I think axles are my first step I hate braking. Where is the cheapest place to get them and what axles do you recommend. The most power i would ever hit them with would be maybe 550 and thats doubtfull unless i spray it. I think the cam swap will happen when i do the converter also i guess this helps a ton. let me know where to order the axles and what axles will work
 

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They wont be real cheap but DSS has some nice ones. I went with a set from a Challenger RT (in my case a 2012). A lot beefier than stock( I also added his 3.06 Getrag LSD and hubs). I think I paid 1500 for all shipped to me. It bolted right in.
Once you start getting up there in power a good idea is to add a Stage 2 valve body to that tranny. With just basic bolt-ons I wouldn't be too concerned but if you get to that 400hp mark I would for certain.
 

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I think everyone has covered everything fairly well. One more HUGE variable is weight reduction. If all you want to use it for is a back up race car, then remove weight (passenger seat, rear seat, stereo/radio, spare tire, etc., etc.). You can most certainly gain a few tenths just by stripping her down.

Also, once you get your DiabloSport tuner, install a 180 T-Stat and change your fan settings. Mine was running around 218-220 degrees at the track and now runs around 190-195. That alone is 2-3 tenths in the quarter mile.

GL! :fing02:
I questioned removing my passenger seat before but was afraid of the impact sensor below the seat. Any input there?

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I questioned removing my passenger seat before but was afraid of the impact sensor below the seat. Any input there?

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Unfortunately no. I have not done it myself. Had a buddy at LX forums in TN that removed his for racing. He never mentioned any problems getting everything back together before he sold it. Not much help...sorry.
 

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Discussion Starter · #15 ·
Has anyone on hear used the 3.92 gears I see you can buy a whole upgraded rear end for 1800 bucks with axles with the 3.92 I was curious what rpm 75 mph would be with stock tires. Does anybody now what the stock gear ration is in a 300C and if some of them came with posi? Mine acts like it just trying to put together the best battle plan. What ratio of overdrive does the car Have I can figure out rpm from that also thanks for all the help
 

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2.82 is stock ratio on a 5.7 C... none came with posi how ever the traction control actually makes them appear to lay rubber with both wheels... but it's technically not... SRT cars have 3.06 and they wake up a 5.7 car however are nothing drastic. Forget anything above a 3.73 for highway use... 3.92's will get you out of the hole like a banshee but at 75 you will hate the manners. IMO 3.23 is ample for these platforms before other mods are exhausted. 3.55 gears are also a very nice in between if you favor more track and town use. 3.73's are a great track gear and fun on the street.. but highway you will be piling on the revs. I run 3.06 to propel my C into the mids 12's, only so much tq multiplication I want to do, prefer good old fashioned power. IMO I would build the power first and then back it with a good gear depending on the manners of the motor when your done. If I had done 3.73's as I planned off the get go I would have loved the instant jump, but now I have globs of power honestly I wouldn't be able to ground it all without running drag radials or slicks on the street which isn't practical. If you go 3.92's say hello to 12mpg on the highway! lol

See here and you will see the general consensus is anything more than a 3.23 on the street is pretty much useless for traction...

http://www.lxforums.com/board/showthread.php/203203-Whats-the-best-rear-end-gears-to-get

I have to agree... I drove a Superbee with 3.55's and 3.73's and both ways it would vaporize rear tires on a dime... his 0-60's plummeted and the car was faster before gears on street tires.. then came the drag tires and it was an animal on the track... but it wasn't usable day to day...
 

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look at my signature, take off the nitrous and you have a high 12 sec car with drag radials. I have only ran the car 2 times on nitrous (75 shot) and ran 12.5 but was spinning off the line even with drag radials. good luck
 

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As others have already said, slicks or DRs are a bad idea with stock half shafts. I broke a half shaft with stock tires on my SRT, and all it had was a canned Predator tune. I do tend to drive with a heavy foot and made probably close to 100 passes at the track before it broke, so that probably contributed to the problem. The bottom line is that if you run DRs or slicks on your car and it has stock half shafts, they are running on borrowed time and will break soon.
 
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