So I have an 03 Tahoe z71 with 3.73s stock, and I'm about to install a truetrac in the rear and was wondering if I should change the gears to 4.11s or just keep the stock 3.73s... I plan on installing a TSP Chopacabra truck cam, long tube headers, tbss intake, and getting it tuned and I've already got the transmission fully built. I'm also planning to throw on some 22 inch honeycombs with tires that match stock tire diameter. Current mods so far are the built racing tranny, and the volant CAI.
4.11s or 3.73s?
- Thread starter Mrwick_02
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Alex_M
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2wd or 4wd? If you're 2wd, I'd say there's no reason not to. If you're 4wd I'd say it's not worth the effort.
It is a 4x4 but I barely use the 4x4... I do understand that I would have to change them in the front diff too and I'm willing to do that... Would like to do some 4x4 launches.
rockola1971
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4.11's youll gain alot off the line and lose some top end. 3.73's You'll lose some to alot off the line and have your topend intact. It all boils down to that UNLESS you are making a towing vehicle that you intend to haul with alot.
So you're making a racecar out of a SUV? "That's heavy man!" --Cheech
So you're making a racecar out of a SUV? "That's heavy man!" --Cheech
I was thinking the same. And yeah I'm trying to make it fast... I've seen some tahoes run 13s-12s which is pretty impressive... I probably won't be able to get to that point unless I throw boost at it but it would still be fun.
Alex_M
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You'll gain a little bit off the line, not a wild amount. If it's in the budget it can't hurt, but you'll see more off the line gains for similar money by going to a stall converter (if you haven't already). If you plan to boost in the future I'd doubly stick with the 3.73s. It will only diminish your returns going to 4.11s.
The lower the gear, the smaller the pinion size and therefore you stand a better chance of damage to that pinion under very heavy torque. Your call at that point and changing both should also not be done on the cheap. The quality gear kits will be $$$.
What kind of stall converter would be good?... It has a stock converter. I don't plan on boost, I want to make as much power as possible N/A.
Well what's the most torque you've seen out of a 5.3 N/A... I plan on making as much power N/A as possible on a 5.3.
I like a small amount of power out of my stock engine. I was wanting more out of my Z71 with the 3.42 gear and then won the raffle at BBP for a traditional tune on mine and that power I wanted is now there. The other alternative was a 3.73 gear, like I had in my 02 LT. What you are wanting to do is not in my realm. My info was just that, info to keep in mind about changing gears.
MrMonte
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I went from 3.73 to 4.11 when I swapped out the 10 bolt rear for a 14 bolt in my 1999 Suburban. The extra low end power was well felt.
Alex_M
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Lots of companies make them, but I don't have experience with any of the big companies. I have a guy local who does all my converters for me however I want them.
That depends on how deep your pockets are and how far you want to go. With the mods you listed you're going to see decent gains. Texas speed has a dyno chart on their listing of that cam with 400 lb/ft at peak. That is certainly measured at the crank, and with headers and no accessories for sure. You will probably see 300 lb/ft at the ground with that combo if I had to guess.
If we're talking quarter mile times, 13s would certainly require boost. You're sitting on a low 19, high 18 second truck where you're at. Stall converter, cam, headers, a good tune, I could see you in the 17s. All this is dependent on altitude of course, and track. These are generalizations.
The biggest limiting factors you face are as follows, in order:
-Maintaining drivability, and even adding some peppiness on the street. By far the biggest issue. Addressing other issues will negatively impact this one and vice versa (except weight).
-Weight
-Cam
-Compression ratio
-Torque converter stall speed
-Heads (can address compression ratio)
Also, if you are wanting to have fun 4wd launching the thing, you may want to look into addressing the weak tie rods.
It really all comes down to what you want to do with the truck, but is sounds like you mostly want a street truck. If that's true then sure, I'd say throw a 2600 stall converter and 4.11 gears in the thing. For a street truck, that should be a pretty happy combo with cam and headers. You could also, when the cam is installed, have your heads worked over a bit. Fresh 3 angle valve job and cleaning up the ports a bit by someone who knows what they're doing. If it were me, I'd find a set of 862 heads on Facebook marketplace or similar. I'd go ahead and have that set worked over and ready to throw on, then sell your take offs. Minimize down time.
swathdiver
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With a 22" wheel you're not going to have much sidewall for good launches, even in 4x4 so the 4.10s would be moot to my way of thinking. Same for the converter unless that camshaft kills your bottom end. But man, I've seen some 6.2 trucks just leap off the line with 4.10s and be gone in a flash!
I just really want honeycombs... You think 20s would be better?... I think the smallest honeycombs are 20s and those would be the stock gmc 1500 slt rims from 2014 to 2018.
swathdiver
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They would certainly be better for traction and ride, just not as good as 17s or 18s for traction and ride. All projects have trade offs, you'll have to decide which things take priority.
Mudsport96
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4.10s for what you say you want to do.
Idk how much highway driving you do, or if this is just a play toy weekend thing. But if you dont highway much go to 4.56s for best acceleration
Loss of top speed is not important really as NA you probably wont have the room to top it out in the 1/4 anyway. And the "Mexico street racing" you would need a decent amount of road to top out 3rd even a C/I 5.3 would have trouble pushing these barns over 130 anyway i would think.
3.73s at 6000 153mph
4.10s at 6000 140mph
4.56s at 6000 125mph
Those are in 3rd since it is 1:1 and likely the only gear you will be able to pull to redline NA so if you are worried about losing top end dont... you will by far need gearing for acceleration.
65 mph cruising rpm in 4th
3.73 1860
4.10 2050
4.56 2300rpm
All with a stock height tire.
Again you will be doubleing price as it is 4x4.
Idk how much highway driving you do, or if this is just a play toy weekend thing. But if you dont highway much go to 4.56s for best acceleration
Loss of top speed is not important really as NA you probably wont have the room to top it out in the 1/4 anyway. And the "Mexico street racing" you would need a decent amount of road to top out 3rd even a C/I 5.3 would have trouble pushing these barns over 130 anyway i would think.
3.73s at 6000 153mph
4.10s at 6000 140mph
4.56s at 6000 125mph
Those are in 3rd since it is 1:1 and likely the only gear you will be able to pull to redline NA so if you are worried about losing top end dont... you will by far need gearing for acceleration.
65 mph cruising rpm in 4th
3.73 1860
4.10 2050
4.56 2300rpm
All with a stock height tire.
Again you will be doubleing price as it is 4x4.
Yeah I get you... I'm also planning on doing the 2019/2020 brake upgrade which requires a 20" rim minimum, so I guess 20" honeycombs it is.
4.11/4.10s it is as I do a fair amount of highway driving... 50/50 highway and city driving.
swathdiver
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I think you'll find it easier to locate 4.10s as they use a 10 tooth pinion gear and 41 tooth ring gear common with the 3.42s and 3.73s for the front and rear.
The 4.11s use a 9/37 pinion/ring gear and I don't see them much for the front differential anymore. Yukon Gear might have ring and pinions in that ratio for both ends though.
I miss 3.90s.
