Gears 3.73 Question/Suggestion

[KDubb619]

Need recommendations from all you knowledgeable gear/electronic buffs:

I recently installed 3.73's on my 2002 GT with AOD-E (4R70W Tranny).
I'm using the Superchips 1725 Max Microtuner with the 91 octane tune with custom shift points/pressures.

The good: Car pulls HARD from stop up to 65 MPH (I'm happy) My 60ft's are way imrpoved
The bad: Car does not downshift to raise my RPM's when 65 MPH or above, my trap speed is down only by 1-2 MPH.

I want either:
(1) The ability to raise my RPM's by downshifting so my car pulls harder at 65+
(2) Increased high-end through a bolt-on recommendation (power adder).

Thanks for any help ahead of time.

Kasey.

 

[fellamansteve]

Can't you adjust the shift points with the tuner?

 

[KDubb619]

I'm still messing with the shift options but it seems to not change much.

It used to pull hard at 65+ but now it's gone, I know the gears aren't causing this (at least I think).

I'm going to try some more tweaking with the tuner.

Thanks for the reply,
Kasey.

 

[MaxedGT]

Your probably not able to down shift at that speed into second anymore due to the gearing change. That's what I found when I changed to 3.73's. I used the default Superchips performance settings and went from a stock 14.3, to 14.1 best 1/4 mile. Later ported the plenum, K&N, magnaflow catback and Steeda underdrive pullies, ran a best 13.773. Run 13.8 consistantly. I found the last combo helped below 3000 rpm and above 5500 rpm. Mines an 01 GT.
That's one thing I miss after changing gears, it went like a bat out of hell when it downshifted to second at highway speeds before.
But now I'm .5 quicker in the quater mile and 4mph faster.

 

[triggz]

Make sure you let completely off the throttle before stomping it. The 4R70W is picky about when it wants to downshift in stock form, changing gears makes it crazier.


I know since I've installed 4.10s in mine, theres a few sweet spots where I can stomp it and the downshift to 1st/2nd will break em loose and tear ass down the road.

 

[KDubb619]

Thanks for the input from everyone

MaxedGT,
I think I'm going to get the pulleys and maybe either a new plenum or port my stock one, sounds like that combo is working for you. I have the tuner maxed on shift points between 2 and 3 hoping it sustains second gear longer, we'll see (fingers crossed).

triggz,
Excellent input, I have found that sweet spot also with my 3.73's, happens right around (+/-)40 MPH, when the car shifts, the wheels bite hard and chirp...kinda' nice since it never did that before. Gears are the ultimate torque multiplier! I'll give your suggestion a shot...you're right about the tranny being picky, and it is even moreso now that the new rear end is in!

My 1/8 best with gears is 9.318 with a 2.145 60 ft. I'm hoping to learn how to launch better with these new gears...I mostly spend about half a second in the starters box spinning my wheels Suggestions???? My launch RPM's are around 1500.

 

[myanarchy]

Suggestions???? My launch RPM's are around 1500.

Yeah. Run the RPMS up to about 3500 and get a decent set of DRs, or go up to 4500 with a good set of slicks

 

[Quadgod]

What gear & RPM is the car in when going through the traps in the 1/4 mile ? I'm curious about both 3:73's & 4:10's. Gears are next on my list & I'm looking for the right choice.

 

[MaxedGT]

Thanks for the input from everyone

MaxedGT,
I think I'm going to get the pulleys and maybe either a new plenum or port my stock one, sounds like that combo is working for you. I have the tuner maxed on shift points between 2 and 3 hoping it sustains second gear longer, we'll see (fingers crossed).

triggz,
Excellent input, I have found that sweet spot also with my 3.73's, happens right around (+/-)40 MPH, when the car shifts, the wheels bite hard and chirp...kinda' nice since it never did that before. Gears are the ultimate torque multiplier! I'll give your suggestion a shot...you're right about the tranny being picky, and it is even moreso now that the new rear end is in!

My 1/8 best with gears is 9.318 with a 2.145 60 ft. I'm hoping to learn how to launch better with these new gears...I mostly spend about half a second in the starters box spinning my wheels Suggestions???? My launch RPM's are around 1500.

I was quite surprised by my gains with the last combo. I was scepticle that plenum porting would help much but with the spacer it worked out great.
I installed an air bag in the rr spring. set at 12-14 psi. Do a good burnout till the tires are smoking. Then left foot on the brake and right on the throttle till the rear tires are almost going to brake loose. Then just hit it hard on launch. With my street tires Goodyear Eagles ZR, that works best, as long as the track is good. A lot of guys suggest only a light burnout with street tires, but I found smoking them good works best. 60 ft consistantly under 2.1, best of 2.03. But It's hard on tires. I'm gonna have to get some drag radials. I'm not sure how much drag radials will help my e/t's. I think you need a high stall torque convetor to make the most of sticky tires.
My best 1/8, 8.845 @ 79.80 mph.

 

[MaxedGT]

What gear & RPM is the car in when going through the traps in the 1/4 mile ? I'm curious about both 3:73's & 4:10's. Gears are next on my list & I'm looking for the right choice.

I'm in third gear with 3.73 and auto at about 99-100mph. Rpm is still pretty low,
but I 've never caught the tach at the end. I'd suggest 4.10 for 1/4 mile with an auto, unless you spend a lot of time on the highway. Most guys who go 3.73 regret they didn't go 4.10.

 

[KDubb619]

Quadgod,

Haven't run the quarter yet, but in the 1/8th I hit the trap at about 5400 RPM @ between 75-76 MPH with 3.73's.

MaxedGT,

I don't use the waterbox with my street tires because the pro's get pissed when we do that...something about water getting into the treads and depositing onto the track??? I saw one dude nearly throw blows over it.

I'm very surprised that pulleys and porting the plenum can make such a difference in times. Cool though! Motivates me!!

Does the airbag help much with launches? I'm looking into slicks still, which I know will help my times. How will the torque converter help with sticky tires though?

I may be full of dumb questions but I'm just starting to drag race...improving my ET every week, can't ask for more!

Peace,
Kasey.

 

[MaxedGT]

Quadgod,

Haven't run the quarter yet, but in the 1/8th I hit the trap at about 5400 RPM @ between 75-76 MPH with 3.73's.

MaxedGT,

I don't use the waterbox with my street tires because the pro's get pissed when we do that...something about water getting into the treads and depositing onto the track??? I saw one dude nearly throw blows over it.

I'm very surprised that pulleys and porting the plenum can make such a difference in times. Cool though! Motivates me!!

Does the airbag help much with launches? I'm looking into slicks still, which I know will help my times. How will the torque converter help with sticky tires though?

I may be full of dumb questions but I'm just starting to drag race...improving my ET every week, can't ask for more!

Peace,
Kasey.

The air bag does help 60ft times. At least I find it makes my launches more consistant.
To take full advantage of sticky tires, guys with manual transmissions launch at high rpms. With an automatic you need a high stall torque convertor to get the revs up at launch and get into your power curve, to get the same effect.
I don't know how much of a gain sticky tire give with a stock torque convertor. Anyone out there know?