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Discussion Starter · #1 ·
Well as some of you may recall, I recently posted a 0-60 time of 4.04 seconds for my SRT-8, but according to the video the timer stopped at around 55mph and not 60. Some of you pointed out that the analog speedo is probably "lagging" behind by a couple ticks and that I should compare it to the digital speedo. Last night I did just that and video taped a 0-125 run:

http://www.titsup-racing.com/video/maggie/0-125.wmv

So yep, the analog speedo does in fact "lag" behind by about 5mph.

Last night I also decided to see just how accurate my speedos are at a steady speed. I didn't use a GPS, but rather the "old skool" method of holding a steady 60mph and using the mile markers on the highway in relation to my odometer. I concluded that my speedo is pretty close to being dead on accurate and is certainly off by less than 1%. Awesome.

I'm really looking forward to installing my 275/40/17 drag radials on the car since it will give me WAY more gear. The stock 3.06's will effectively become 3.42's! According to my calculations, the difference will be HUGE in the quarter. I will be able to go approximately 113.2 MPH in 3rd gear @ 6400 RPMs. If I find that the car is shifting to 4th just before the line, I'll simply use the autostick feature to shift and then bump the rev limiter up a hair (if need be). I don't think holding 3rd will be much of an issue thanks to the Predator.

Now for the good stuff on just how big a difference the 275/40/17's will make. Using one of the Predator dyno sheets for a stock SRT-8 with just a tune, I compiled a little chart of the RPMs and WHP seen in 3rd gear with the stock 245/45/20's and then the RPMs and WHP seen in 3rd gear with the BFG 275/40/17's. The results are astounding:

3rd gear RPMs & wheel HP realized in 1/4 mile with stock 245-45-20 tires (3.06 gears):

4300 - 305 WHP
4400 - 312
4500 - 323
4600 - 331
4700 - 343
4800 - 352
4900 - 356
5000 - 362
5100 - 366
5200 - 370
5300 - 373
5400 - 376
5500 - 379
5600 - 384

3rd gear RPMs & wheel HP realized in 1/4 mile with BFG 275-40-17 tires (effectively 3.42 gears):

4800 - 352 WHP
4900 - 356
5000 - 362
5100 - 366
5200 - 370
5300 - 373
5400 - 376
5500 - 379
5600 - 384
5700 - 385
5800 - 389
5900 - 392
6000 - 393
6100 - 393
6200 - 393
6300 - 393

3rd gear Average WHP realized in 1/4 mile with stock 245-45-20 tires (3.06 gears): 352.28 WHP

3rd gear Average WHP realized in 1/4 mile with BFG 275-40-17 tires (effectively 3.42 gears): 378.50 WHP

Average WHP gain in 3rd gear with the drag radials vs the stock tires: 26.22 WHP!!!

This is why gears make such a huge difference in drag racing!

Now of course this does NOT factor in torque converter slippage, but since that applies for both setups, it shouldn't really make too big a difference.

Sources: DiabloSport Predator Dyno Sheet, Gear ratios & other specs, Gear Ratio / RPM / Speed Calculator

Lastly, here is my proposed recipe for going 11.99 with stock displacement, stock compression ratio, stock heads, stock cam, no juice, and no power adders:

Mild Steel AirHammer CAI (just ordered it for their new super low price!)
JBA 3" exhaust
Magnaflow high flow cats
275/40/17 BFG Drag Radials on 17x9 OEM '03 Cobra SVT rims
3.42 effective final drive change (due to the rear tires)
ProTorque 2800 Torque Converter
A custom street tune with the Predator done by yours truly. I'll be tuning with a wideband and running 100 unleaded or 104 unleaded fuel for the track.

I project an [email protected] with those mods on a 50-60 degree day and good track prep. Bone stock 6.1 FTW (hopefully!) :knockout:
 

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I'll give you a 12.2-12.4 run.
Don't think you will break into the elevens, but a low twelve second time is pretty damn good.
 

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The tires will no doubt be worth a min of .3 if you are able to launch on them....
You will need a serious 60' (1.6X) to get anywhere close to that 11.99 so make sure you upgrade your axles first or you are in for a very bad day.

I am firm believer in the shorty tire (check sig)..... and with the ability to raise rpms via the diablo we have eliminated any reason to have to hit 4th gear.

Good luck man.
 

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Discussion Starter · #4 ·
I was just reading your signature and thinking that ET and trap is kinda disappointing for all those mods. Then I realized you have a 5.7! That's very impressive! I'm assuming you're on stock 5.7 halfshafts? Have you had any problems with them?
 

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While trap speed is a great indicator of top end HP it really isn't what I am after...the 5.7 is all about midrange torque and getting out of the hole. 111-112 is plenty of MPH to get to 11.9 if it is applied to the rear wheels correctly (ie killer 60').

After 150+ plus passes in my car I would say the 5.7 axles seem to have no problem living in the 1.7 60' range....Hell InferAl has been hitting 1.6's with no probs so far. The real trick would be putting the 3.06 gear in the 5.7 rear.....we are working on that.
 
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