Horsepower gains?
- Thread starter nvsteve
- Start date
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swathdiver
Full Access Member
What is the axle ratio?
3.73 posi gear. Yes it hunts gears. No pull below 3000 rpm on long grades. Shifts down to 2nd gear which winds rpms to around 4500 which makes me nervous. Non towing performance is ok for such a heavy vehicle. Engine seems to be good, no oil consumption. Transmission was rebuilt about 5k miles ago and shifts fine. I like the car otherwise but wondering whether I should sell it and get something newer with bigger engine.
swathdiver
Full Access Member
Ok, what size tires are you running? What motor is in there, the L31 SBC? Ideally, you want the engine to be at the peak of its powerband, torque, when towing. The L31s peak came in at 2,800 RPMs. Of course, too much gear then takes away from daily driving until you add gears to the transmission and or raise the torque band of the engine.
Mechanic421
06 Denali XL
I am pulling up some good grades. I never tow in od. And when I hear it unlock the converter I let off some and let it slow some before it kicks down to second. I don’t like the 4500 pulls either.
swathdiver
Full Access Member
Ok, I think the trans in those is a 4L60 and if so, the truck will be turning about 2800 RPMs @ 69-70 MPH in 3rd gear.
Slow down or get more torque. Shorty Headers might add about 10-15 ftlbs of torque, a camshaft upgrade maybe 15 ftlbs more. Might first do 4.10s which would cost less if it's RWD than the other two. Oh, almost forgot, who does tunes on those older trucks? That's what I would do FIRST!
Finishing my thought on 4.10s: At 70 with them, you'd be turning about 3100 in 3rd or 2200 in 4th, not likely to drop into 2nd anymore which would be over 5100.
Time for a Duramax diesel rig with the Allison Transmission. Absolutely the best towing rig I ever owned.
swathdiver
Full Access Member
I miss my '88 F-SuperDuty with 7.3 International, ZF 5-Speed Manual and Dana 80 with 5.13 gears.
Mechanic421
06 Denali XL
Yes u r right, but we all can’t afford a duramax.
I can't afford one either unless I found a nice used one. I don't tow anything so it is not needed.
https://eugene.craigslist.org/cto/d/springfield-2002-crew-cab-chevy/7020662545.html
From around here with no rust.
https://eugene.craigslist.org/cto/d/springfield-2002-crew-cab-chevy/7020662545.html
From around here with no rust.
Tonyrodz
Resident Resident
Towed a 53' enclosed trailer with 2 Lambos with that setup in a Silverado, we drove from Nj to Cali. That baby didn't even breathe hard! Awesome setup!
drakon543
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my 97 has intake shorties and basically a muffler swap. 265 70 17s and im not sure on the gearing. ive towed an 04 f150 i think it came in at 5900lbs or something. it did a pretty good job there but again not sure on the gearing.
Intake = bad idea (no real gains, just a lot of hot air)
Headers and exhaust = good idea (nearly any vehicle will benefit from this)
PCM tune = good idea (nearly any vehicle will benefit from this)
Maybe the exhaust and tune together would make a noticeable difference.
Regearing the truck is the most straightforward way to solve your problem.
Headers and exhaust = good idea (nearly any vehicle will benefit from this)
PCM tune = good idea (nearly any vehicle will benefit from this)
Maybe the exhaust and tune together would make a noticeable difference.
Regearing the truck is the most straightforward way to solve your problem.
