For those of you that remember the infamous "Gear" post from several months ago, don't worry, I know that gear ratio changes don't add horsepower etc...

Having said that, I recently purchased a pair of P275/40R17 BF Goodrich Drag radials. If I replace the taller rear 295/45ZR18 Goodyear F-1s with the smaller diameter drag radials, this will obviously change the final drive ratio and should help lower 1/4 mile ETs.

F-1 = 28.45"
------------ X 3.55 = 3.94
T/A ~ 25.63"

How many guys out there have used smaller diameter tires/slicks and what is your take on the increased 1/4 mile performance.


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1999 Black Roush-Lowered Lightning - w/Super Chip (YEEEOW!), JBA Headers, Power Surge air kit, AAD Cobra hood, carbon fiber dash kit, CD Changer, Towing Package,Grey Rhino, clear corner lenses.



[This message has been edited by sixpipes (edited 01-10-2000).]

 

The 255 5016 DR`s that I am using are 26"tall. I hit the traps at around 5000 RPM,

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99 SVT Lightning
BLK. #1476 5/20/99
2 Chamber Flowmasters
Downs Air Intake
B.F.Goodrich Drag T/A`s
Superchips
A-pillar Phantom Boost Guage
Redline Water Wetter
Sportmaster Flip tonneau
Tow package
CD changer

Best run to date
13.064 @105.33

"Empty Pockets Racing"Drag Race Team NJ-DE

 

Spirro,

I guess that puts you at 3.96. I've been thinking about doing a gear swap. Isn't there a 3.92 kit anyone?

Does anyone have any idea as to how much a gear swap would affect mileage? My L is my daily driver... Mostly city miles... Could mileage actually improve since it would be easier to get the truck rolling?

Also, not to stir up controversy like the previous hp vs. gears thread, but with higher revs at any given speed, wouldn't the sc spool up sooner? Wouldn't this increase boost and hp contributed due to the increased boost a given speed?

[This message has been edited by LightningDammitt (edited 01-05-2000).]

 

Alot of the guys around here put a small tire on 95 lightnings. It did make them quicker. I put 17 inch 285-40-17 on my 99 silverado with weld wheels and i actually got slower by .4 in the quarter mile. ON the fords i think it always works, on chevys, i think the 3.42 gear is the best .I had a 96 vortec350 in a choo choo truck with 3.42 i went to a 4.10 and i was running .5 seconds faster with 295-50-15 than 3.42 w/275/60/15 go figure?????????????. the truck was only good for 95mph in drive. and in overdrive i could slowly bring it up to about 120mph , the only problem is soon as i hit the gas too much it would drop in drive ,redline and slow down. I never will know if that chevy spec could have been altered.It was a rocket in its time though. i was running 14.9 while 95 lightnings tweeked a little bit were running 15.2-14.9. My 99 5.3 silverado ran a best of 14.6 with a chip and exhaust and dimantled thermostat

 

BADDASSSVT-I'm very impressed with 14.6 from just a chip and exhaust. Where did you run at, with what kind of tires, and what was your axle ratio?

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Black 99 Silverado 5.3
HPP3, Stull Billet Grill, Gibson Super Truck, Custom Fresh Air Intake, GTS Tail Light Black Outs, "Leveled" 2" In Rear.
15.02 @ 90mph with 2.7 60'

 

seems as if some chevy owners may be checking us out over here!

 

1999 chevrolet 5.3 LS 5.3 3.42 gears and factory posi (limited slip)short box(black)

Flowmaster muffler 1 into 2 strait back to rear bumper.

I snapped out the thermostat, because it is part of the housing for 99s. I think they might make one now though. The truck ran really cold without a thermostat.

Hypertech Programmer III
6100 rev limit
+9mph 1st to second shift about6000rpm
+9mph 2nd to 3rd shift about 5900rpm
with tuning and i told the computer i got a 180 thermostat.

17x11 rear weld split six wheels (rear)
17x8 front
285/40/17 and 255-50-17

2+4 lowering kit

I have the slip from new england dragway right here. you will be surprized at the 60ft times im sure.I got this time with the factory tires with normal air pressure on a pretty decent night.on APRIL 30,1999@ 8:43pm
R/T....580
60FT...2.104
330....6.098
1/8....9.416
MPH....74.38
1000...12.26
1/4....14.696
MPH....92.35

I noticed a big loss using the weld wheels,(alot shorter than stock).My best was 14.9




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1999.5 LIGHTNING
WHITE #3700
DOB:8/17/99
CD CHANGER
TOWING PKG
TONNEAU CONER {FACT.}
STOCK
13.88ET
98.86MPH
NE DRAGWAY N.H.

I now have superchip and downs intake I am just waiting to install in APRIL 1/04/99

98 YAMAHA BLASTER
97 HONDA 600F3 WHT/BLK
99 VW BUG GREEN
TAYMIA SVT LIGHTNING
WHITE R/C TRUCK
BBURAGO WHITE 1/18
(painted) LIGHTNING

USED CAR DEALER
SELF EMPLOYED
RAYMOND MACE
N.H.

 

Oh yea i forgot to tell you, I raced a black lightning in the summer. on Rte 101 in epping to raymond on and off. I noticed a bolt coming on strong.First time for me. He got behind me, i punched it.my truck only went to 128mph until shutting off.All the way to 128 the lightning did not gain one inch! My truck was a screamer.I atribute some of this to him having 3 peole in the cab while i was solo.we then were at the toll booth (separate lanes on purpose)we both punched it. I was absolutley even with him up intil 70mph and he started getting about a half nose on me and we went two separate ways.I was not impressed at the time.I think first he had more weight, second he probally had an earlier model that was slower . I set up my chevy so i could hang with lightnings, I went by the times they posted in mags.14.4-14.2 .After that i was very happy with the "right" modifications i had done to the chevy.Im glad I bought my lightning, cause now seeing mine does ,13.8 i would be pi$$@% for a lightning to smoke me by 4 cars.I figured i spent 20k and 1k on mods HA HA HA HA and that putts spent 30+k for that? WOW. But we all smarten up sometime. after my mods ill be running 13.4 or so Now i realize my chevy had no real chance of being a lightning smoka.YOU REALLY CANT COMPETE WITH THE LIGHTNING FOR 30K.NOWHERE NO HOW PERIOD......

 

Amen Brother!!!!

 

Pic of my Drag T/As on progressive wheels.




Pic of the Lightning after a little photoshop exersize.




The truck will actually sit 1" lower than the photo indicates due to the difference in stock 18" and Goodrich 17" tire profiles.


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1999 Black Roush-Lowered Lightning - w/Super Chip (YEEEOW!), JBA Headers, Power Surge air kit, AAD Cobra hood, carbon fiber dash kit, CD Changer, Towing Package,Grey Rhino, clear corner lenses.




[This message has been edited by sixpipes (edited 01-08-2000).]

 

That really looks SWEET!

 

Sixpipes,

These questions may have been asked before but: exactly what size are the tires, and did it throw off the speedometer?

thanks,
Mike

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99.5 Black Lightning
PowerSurge Cone Filter
JBA Jet-Hot coated headers
Flowmaster muffler
So-Cal Lowering Kit; Cal-Tracs traction bars
Watter Wetter
Lo-Jack

 

Brimstone -

I haven't actually had them on the truck yet. The above picture was a product of a little photo shop magic. I will be putting them on next Friday, when I go to the 1/8th mile track here in Denton. Tires are P275/40R17 on a 17x9.5 rim.
I'm not a fan of the smaller diameter tire look, but I couldn't find an 18" drag radial or a 45 series 17" drag radial. According to my calculations, the speedometer should be reading 65mph when I'm actually doing 60mph.

Thanks for the comment BADASSSVT.

[This message has been edited by sixpipes (edited 01-09-2000).]