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Sluggish Silverado 4.8L

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Old 02-09-2011, 11:32 PM
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Originally Posted by gs7793
thats the way to go

i honestly can't belive they would put 4.8's in crew cabs...there really is no way to make that truck get out of its own way, especially pulling something with a load full of people, without voiding the warranty....

if you dont want to do an engine swap, look into putting a front mount turbo on your 4.8, thats what im going to do. kb racing on here sells super nice looking complete kits for 2500. foose04 on here make 623rwhp give or take a few, on his turbo 4.8 @15psi with an ls6 cam/springs (which is about a 150 dollar cam package used)......definately something to look into

or you can build your own turbo kit
Count me in on the 600+ rwhp lol but I'll start with lt headers first then work my way up
Old 02-10-2011, 07:35 AM
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Originally Posted by gs7793
thats the way to go

i honestly can't belive they would put 4.8's in crew cabs...there really is no way to make that truck get out of its own way, especially pulling something with a load full of people, without voiding the warranty....

if you dont want to do an engine swap, look into putting a front mount turbo on your 4.8, thats what im going to do. kb racing on here sells super nice looking complete kits for 2500. foose04 on here make 623rwhp give or take a few, on his turbo 4.8 @15psi with an ls6 cam/springs (which is about a 150 dollar cam package used)......definately something to look into

or you can build your own turbo kit
Are you serious? You think a 4.8 in a cc isn't cablable of getting out of its own way? I bet you $100 with full bolt ons, cam and milled heads, I run mid to low 13's. It will be later in the year likely before it's done, but with the gears and converter, without longtubes, I bet I can squeak a 14.5 out of it as long as traction isn't an issue (no dr's yet).

The 4.8 is weaker than the others in stock form, mostly in the torque catagory. Do you realize with a decent converter, torque (in the range the 4.8 lacks) is not even an issue. So then your working with a 15 hp difference with a 5.3?

BlackGMC ran the same kind of times that most run with cammed 5.3's. I know cajun and v8 were exceptions, but there is always an exception. There have even been people hit 13's with just bolt-ons.

Will I eventually change the engine, probably. But everything I'm doing will carry over.
Old 02-10-2011, 08:10 AM
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I ran mid 14s with intake, tune, full exhuast in my ext cab with 26" tires. If your worried about the warranty, at least put in some lower gears and that should help you out.
Old 02-10-2011, 11:46 AM
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I'm sure the gears you have in that thing are 3.23's, so thats a major hit. 4.8's in the Crew Cabs with those gears are horrible. At least some 4.10's and a 3000 Stall Torque Converter, ditch the flowmaster for a 3" single in/out magnaflow or something similar exhaust, get the tune, and I guarantee you will be much happier.

I guess I'm one of the few thats actually happy with my 4.8 liter, even with the few mods that I have, of course mines not a crew cab either. lol.
Old 02-10-2011, 12:04 PM
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Originally Posted by L33Z71
ditch the flowmaster for a 3" single in/out magnaflow or something similar exhaust,
Waste of money. Magnaflow will maybe increase HP what, 2 or 3? Not worth it IMO.

Everyone on this forum is on Magnaflow's nuts
Old 02-10-2011, 01:41 PM
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I've owned several sets of flows, first set was the 13" 2 chambers on my 90 GMC. They sounded good. I have a magnaflow now because I wanted something different. I like the magnaflow better. I liked the flows before they came out will all the b.s. models like the deltaflows etc.
Old 02-10-2011, 01:56 PM
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i had a 4.8 once hence the ONCE part lol. it was ok in a rcsb for gas and that was about it. u want power Like Gs said turbo or like i said built 6.0 it all comes down to how deep your pockets are just my two pennies.
Old 02-10-2011, 01:59 PM
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ohh and 2 the muffler conversation had both flows and magnaflow didnt see any gains over stock actually felt like a lost a bit down low over the stock setup, but i do like teh sound of the maganflow except that it drones like a ****
Old 02-10-2011, 06:40 PM
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I went with a wheatley tune, he seemed the most customer service friendly and answered a lot of my questions quickest. I went with the 87 tune for now, I'm gonna change the cam and put in 4.10 gears after this summer. I'll retune with the 91-93 when I get those put in. Is there a link to $2500 turbo? That maybe an option. Anyone know of any good performance shops in Miami/Ft. lauderdale area?
Old 02-22-2011, 10:18 PM
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https://www.performancetrucks.net/fo...d.php?t=477390


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