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Discussion Starter #1
A friend of mine has an 01 2500 with the 8.1. Ive been trying to help him find some performance parts like headers, cai, tune. I dont think he wants to do anything internal quite yet. I know there is a guy on here with a green 2500, hopefully he'll chime in.
 

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Blown Big Block
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For a tune definelty get a BlackBear pcm, for cai pick whichever he likes, but even with my blower I cannot outflow the factory airbox, good luck finding headers for the 8.1 I got The Other Guys headers,, but they are out of business, scrap the factory boat anchor exhaust and go with either a Magnaflow or Flowmaster dual in single out. Those items should wake it up nicely.
 

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HOT AIR BALLOON OWNER
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Tune will really wake it up, Nick on here has been working his up on the cheap to see what it'll do. Ran in the 14s with the basic bullshit.. intake/exhaust/tune.

I can only assume the cam is comical at best as it's dead quick around 4600rpm so I'm confident a cam will add some stupid power gains on the cheap.

Stainless Works mades/made LTs for it too.
 

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Discussion Starter #4
I talked to him again. He has a k/n cai and no muffler. I called stainless works and they said the headers for the 03 and 04-05 wont fit the 01 as far as a direct bolt up. They did say people have made them fit with some cutting and welding but its hard to justify cutting up $700 headers. Ive heard tog headers are good for the 8.1 but I cant find them anywhere. What cam would you guys recommend? His truck has a 6" lift with 35's and he tows occasionally. He said he wants to atleast maintain fuel mileage if not improve it; he said if he can reach 10mpg then he'll be happy.
 

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GMFS slowest truck :read:
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i guess this is where im supposed to chime in...

tune, cheap intake, and corsa catback got me a 14.92 timeslip. nothing great, but it is a 6900 lb truck. Tune makes the biggest difference...for shits and giggles (and to see what the fuck is up with my transmission :( ) i put the stock tune back on. its VERY comical. on 265s its tough to spin tires. tuned, i can light both rears up into 2nd. I dont think from a dead stop it will chirp them stock...lol. The tune has some decent TQM and also a horrible PE delay and 8.1s have false knock. cut that out, add a little timing, slightly desensitize knock sensors, go out and have fun. my WOT timing was near 28-29* before i started over tonight...on stock tables you are lucky to see 20+.

There is not a whole bunch of aftermarket stuff out there for them. They have tons of potential, but the market just isn't there. Good luck finding used cams, headers, etc like you can for the LSx motors...its 100% night and day difference when it comes to parts as to whats out there and having both a genVII bbc and a genIII sbc ive seen this so much first hand.

BTW...easy way to gain torque back is to go to a single 3" high flow muffler...stock piping is DUAL 3", which is rediculous, and if hes running without a muffler at all, hes losing so much scavenging, and with that, so much torque.
 

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HOT AIR BALLOON OWNER
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Hows about this for a cam?

220/228 (270/284), .530/.530 113LSA, 109ICL :banana-mario:

AND - lol @ no muffler.



In the time I can remember, I've seen ONE set of used 8.1 headers, SW long tubes. I see JBA short often, gotta be better than the crappy log manifolds... but I wouldn't expect much power until you get into the 3000rpm+ area for those. 1.75" primary is what I'd go for due to the low RPM nature of the 8.1

Whipple used to have an IC'd kit, yes intercooled! But, finding one of those will be comical at best.

You could run a butt turbo on it and use a Dmax IC, +7psi into nearly 500" would help.
 

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GMFS slowest truck :read:
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5,501 Posts
Hows about this for a cam?

220/228 (270/284), .530/.530 113LSA, 109ICL :banana-mario:

AND - lol @ no muffler.



In the time I can remember, I've seen ONE set of used 8.1 headers, SW long tubes. I see JBA short often, gotta be better than the crappy log manifolds... but I wouldn't expect much power until you get into the 3000rpm+ area for those. 1.75" primary is what I'd go for due to the low RPM nature of the 8.1

Whipple used to have an IC'd kit, yes intercooled! But, finding one of those will be comical at best.

You could run a butt turbo on it and use a Dmax IC, +7psi into nearly 500" would help.
you dont have to let everyone what i want for a cam for mine! hahaha.

unless you have real reason to build it quick, just find deals on shit. it happens, just rare occasions. 300$ for my corsa catback and 100$ for my intake. 100$ on my tune (dont have unlimited credits for HPT yet...). 500$ and ive knocked off easily .5 sec. shop around, be thrifty. dont build it in a week and let deals fall in your lap.
 

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Discussion Starter #8
I appreciate the help guys. As far as the exhaust goes, should he run true duals at all or no? If not should he go with the same set up as the sbc aka 3" y into a muffler with 2.5" out?
 

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GMFS slowest truck :read:
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duals are bad. period. NO scavenging at all. y it into a free flow 3" muffler and dump it how he pleases. i PROMISE there will be a decent increase in tq.
 

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Discussion Starter #10
ok cool Ill let him know. Is it ok to do a cat delete? Nicholas what did you get as far as headers?
 

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how do you y it into one there's barely any room before the muffler or after the rear most cat? And what would you suggest for a quieter muffler preferably louder than stock but little to no drone in the cab. I have a 2001 Suburban 2500 with the 8.1. Looking for some upgrades. Likely to be towing a lot this summer have a 31' Jayco trailer and would like to see performance and hopefully mileage increases. Thought about Flowmaster 50 or 70 series mufflers otherwise open to opinions. Thanks Greg
 
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