3:73 gears and Jmod Question - TCCoA Forums
 
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post #1 of 7 (permalink) Old 01-18-2005, 10:48 AM Thread Starter
 
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Exclamation 3:73 gears and Jmod Question

I have searched and the forums go around this and get off subject.

I have a 95 Bird with the 4.6L rollin on 17x9 rims/Mohawk Predator 245/45 tires. Traction on the tires are AA and TW is 400. Mods- TB CAI in front of tire w/ 9in K&N cone, TB spacer, True dual exhaust w/ Magnaflow mufflers, and BM shift kit. I get a bit of wheel spin off the line. It kinda picks up a tad bit and turns to the left a little.

1a. Are my tires slowing me down (the rims feel as light as the stock ones)?
2a. Is the CAI slowing me down where it's mounted?
3a. Would a smaller rim (16") improve times? Does the tire tire on the rim help out with traction?

I will be doin the mild Jmod this week (takin out the BM shift kit) and leavin the 1-2 spring and the 2-3 spring out.

1b. Will this increase off the line wheel spin?
2b. Will this bark 2nd gear or even 3rd?

I wanna put a T-loc and 3:73 gears in.

1c. With my tires, will the 3:73's ALONE improve my times?
2c. Will the T-loc with 3:73's improve times?

If I can hook up, I can run dead even with my buddy's 95 auto 5.0 Stang. He hooks up way better on his stock 16" rims.

I tried to make this orderly. I'd appreciate it if all questions were answered. Sorry about the on goin of the gears and Jmod questions.

Last edited by Nightmist_Outlaw; 01-18-2005 at 11:00 AM. Reason: messy
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post #2 of 7 (permalink) Old 01-18-2005, 08:49 PM
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I would have to say this from experience:
anytime you put a wider tire up front, it will slow down your times. its rolling, frictional mass-both weight, and rolling resistance are a factor-not to mention aerodynamics(tire still has to cut a hole in the air)

if you add 3.73's, traction will be harder to obtain, simply due to wheelspeed off the line. However, if you install a trac-loc, that will provide you with alot better "positive" traction. gears, without trac-loc will ruin your day at the races. period.

Anytime you get a wider footprint on the ground, your traction % improves. if you change the roll-out of the tire(shorter tire), your traction % decreases slightly. If the wheel is heavier, it will slow you down, since it is "mass".

The JMOD will not affect your launch, as it only effects shifts. Yes, with 3.73's, and any HP increases, a JMOD can "bark" into second gear, if traction is an issue. But into third, it is doubtful. But then again, once you feel the 2-3 shift with no spring, you wont care how it "sounds"...it will feel like heaven.

The best thing you can do is find the "optimal" air pressure to run. But a radial tire is designed to absorb impact. period. If your tire is under a load from a launch, your tire's sidewall will do everything it can to adhere to the pavement. But if you start running an air pressure that defeats the tire's purpose of absorbing impact, you will "light 'em up".

The best thing you can do with your set up is:
JMOD
front tire pressure to 36 minimum(for track use only)
rears to 30-35 psi(too low will hurt you due to sidewall flex/rebound)
3.73 w/trac-loc

if you want more "positive traction", you will need to deal with chassis bracing(see JL), or ET slicks/drag radials/better rear suspension set up.

If you want the best of 'streetability' and "drag strip launches", then you will have to spend some time practicing launch rpms, and rear tire pressures.

have fun.
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post #3 of 7 (permalink) Old 01-18-2005, 09:14 PM Thread Starter
 
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Thanks!

Thanks, that's what I wanted to know. What about the air filter is front of the tire, good or bad, pros n cons anybody?
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post #4 of 7 (permalink) Old 01-18-2005, 10:34 PM
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Quote:
Originally Posted by Blackicelsc
If you want the best of 'streetability' and "drag strip launches", then you will have to spend some time practicing launch rpms, and rear tire pressures.
The biggest problem is that the track and the street are completely different. I can get my car hooking up great on the street, put it on the track and I get my avatar. I have some slicks for spring just need to get them on some rims.

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post #5 of 7 (permalink) Old 01-18-2005, 11:27 PM
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nightmist, if your CAI is completely isolated from hot engine air and you've replaced the violin-case intake tube, then thats the best its gonna be
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post #6 of 7 (permalink) Old 01-19-2005, 09:59 AM
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Quote:
Originally Posted by dirtyd0g
The biggest problem is that the track and the street are completely different. I can get my car hooking up great on the street, put it on the track and I get my avatar. I have some slicks for spring just need to get them on some rims.

Alan

I find it truely amazing that a car can hook up on the street better than on the drag strip, which is *supposedly* a prepped surface.

I can smoke my tires for at least 75 feet off the line if i leave at 1500 rpms...but if I leave from a dead idle, it will hook up alot better. Of course, it is a full-street car...street tires, and still a 3.08-peg leg rear!

The problem I have with running slicks on a street car is, typically, the tires are the "breaking point". They will usually break loose before anything else does. I have seen too many "street cars" shed axles when slicks are applied. Of course, if you want to hook up... your options are limited. Install stronger parts, that can handle the torque-hit, and you will be running numbers far better than you would with stock/street parts.

alot of people dont even realize, even when you think you are hooking up, there is still some slippage happening. if a car gets 100% traction, then the drivetrain takes the full brnt of the "hit".

I dont understand the air filter question, in relation to "slowing you down". Is it protruding from the body of the car? Or are you just curious if it is effecting power output. The question sounds like you are asking if it is creating drag... but I assume it is still in the fender well. if you are drawing cool, fresh air...most likely it is helping, not hurting. But if it is drawing hot engine air...then it isnt doing squat...the benefits of a CAI are only that is it is drawing COLD air(C in CAI). Otherwise, its a HAI.(Hot air induction) Hot air is bad for making power(unless it is boost-fed via a turbo, in which case it shoudl pass through an inter-cooler to cool it before induction, but thats another topic!
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post #7 of 7 (permalink) Old 01-19-2005, 10:26 AM Thread Starter
 
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I am concerned about the sharp bend right after the MAF to go to the fender well. I "heard" it messes the reading up but I've never seen a CEL from it.
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