Allison 5sp: Lb7: 37 tires and 3.73's
- Thread starter diesel53
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Yes, unless you do twins. James, chevy1925 has been running that set up with twins for a while. Maybe he'll chime in. The recommendation for 37's is 4.56's.
Not sure how twins would help beside just adding more power. And 4.56 is going to kill highway mileage? It's not going to be a towing truck I'm just not sure how much power that tall gearing will suck from me.
The gearing won't make up for the added weight and increased unsprung weight of your lift/wheels/tires. It will "feel faster" but you won't see much difference at the track.
That's kind of what I thought because you may increase acceleration but you lose speed at the same time. So do you think it's worth changing? They measure 36 inches on the truck and weight per corner is 113 pounds.
Your bfgs are probably lighter but I've been semi weight conscious with my set up.
Nope. My tires prior to this weighed 125lbs per corner. These weigh 110lbs per corner. (Wheel weight included on both). The difference from that was noticeable.
Unless you tow, wouldn't spend the cash. Twins would be a better way to go
Unless you tow, wouldn't spend the cash. Twins would be a better way to go
What tires did you go to?
Thanks for the input, I appreciate it. And I think if I mess with a turbo set up id end up having to build a motor haha. Trying to stay away from that.
I never had an issue when I was running 37s 
Did notice a little bit when I dropped back to 35s but I just had to feather the pedal more
If your truck pulls ok though the gears then I wouldn't mess with it. drag racers gear the truck to be at the top of the power band at the traps. If your truck pulls fine down low then I would leave it
Did notice a little bit when I dropped back to 35s but I just had to feather the pedal more
If your truck pulls ok though the gears then I wouldn't mess with it. drag racers gear the truck to be at the top of the power band at the traps. If your truck pulls fine down low then I would leave it
I run 37's on my LB7 with stock gearing. I don't have a problem at all. Tires are Pro Comp Xtreme AT's. For tread wear and quietness they're hard to beat.
Nick
Nick
I'm running 4.56's with my 37's. I like the low end torque with the gears but mpg's suck. I've thought about dropping down to 4.11's to get better mpg's.
I mean, we all know low gearing is just a cover up for a weak engine
No but really, with 35s I wouldn't change the gearing. With 37s and a stockish tune I would think about changing the gearing. JMHO-if you have a built trans and if you tow a lot twins; the truck will do just fine with stock gears and 37s
No but really, with 35s I wouldn't change the gearing. With 37s and a stockish tune I would think about changing the gearing. JMHO-if you have a built trans and if you tow a lot twins; the truck will do just fine with stock gears and 37s
37s+twins+towing=bent rods
I meant on a 400ish HP tune, but yea I should have been clear about that. Never know who will miss read one of these threads...
Really as long as you don't get greedy the stock turbo will do just fine-but if you do upgrade your air system I would go twins since it might be a pita to stay on top of a big single.
Really towing (assuming you are not retarded) the killer is the heat, the stock cooling system can't take 500 HP for really more than a few minutes
Lol you guys are too funny.
Ya I would not be comfortable twining unless I built the motor up to handle it.
For now I will see how the truck pulls when I get the bigger tunes on it. It pulled pretty well with the stock Trans race tune already. If its still not enough ill do 4.56 gears.
Ya I would not be comfortable twining unless I built the motor up to handle it.
For now I will see how the truck pulls when I get the bigger tunes on it. It pulled pretty well with the stock Trans race tune already. If its still not enough ill do 4.56 gears.
Re-gear it..it was one of the best moves I made..especially towing in the 65mph range..3:73's like to jump between 4 and 5 when driving in the hills. Plus you get kill off a ton of lag, city driving is where I felt the biggest improvement...I'm at like 2100rpms at 75 I think..I'll check soon as I get home..
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I have to send my ECM back to tony. Waiting for my q45 to get done so I have something to drive while I do the Trans and ECM in my truck.
I just don't think I'll be towing much if at all so it hasn't been a big concern. I really hate having to scream a motor on the highway, if you are at 2100 at 75 that's not as bad as I was thinking. I haven't ran Calcs on speed and rpm yet