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Any dyno numbers from the headers?

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Old Apr 21, 2010 | 09:57 PM
  #21  
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The average tq is where it's at.

UNDER the curve, people...under the curve.
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Old Apr 21, 2010 | 10:02 PM
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Looks like I'm going catless then.
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Old Apr 21, 2010 | 10:04 PM
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only way to go IMO!!! Minus the eco restrictions in your repspective states LOL..sorry guys!
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Old Apr 21, 2010 | 10:45 PM
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Maybe a stupid question,but how many people with catless DP have had there car tuned.With out a proper tune,couldn't you burn up your pistons?

I'm stuck between warrenty and the problems with the headers(whistle,etc),if I keep the cat on there is no real gain since in chocking at the cat.but if I go catless,I have to worry about check points,SNIFFERS,smog,etc...With the couple of gains I've read about,I think it is worth it,and then I don't...O well carry on....
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Old Apr 21, 2010 | 10:51 PM
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Originally Posted by 1CL3ANSUP3RSPORT
Maybe a stupid question,but how many people with catless DP have had there car tuned.With out a proper tune,couldn't you burn up your pistons?

I'm stuck between warrenty and the problems with the headers(whistle,etc),if I keep the cat on there is no real gain since in chocking at the cat.but if I go catless,I have to worry about check points,SNIFFERS,smog,etc...With the couple of gains I've read about,I think it is worth it,and then I don't...O well carry on....

YOu don't need a tune but I got one.
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Old Apr 21, 2010 | 10:58 PM
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Originally Posted by AlabamaGuy
YOu don't need a tune but I got one.
W/O a tune wouldn't it run to lean,which possible burn up your pistons?
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Old Apr 22, 2010 | 04:04 AM
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Originally Posted by DavidGXP
our engines put out 335 ft/lbs at the flexplate.

Our intake ducting is rather small too. Almost all LS motors have a 4" tb opening (not butter fly) and have MAF housings that are around 3 3/4-roughly 4". Our engines have a 3.5" tb opening with 3.25" maf inlet and outlets. Pretty much V6 stuff guy's.

I thought they put out 323lbs at the flexplate.

Bare with me because I'm use to the maf and TB being referenced in mm but, I thought the LS4 came with a 78mm TB, if that's the case then it's plenty for what most LS4's will ever see. I'm not sure about the maf though, does anybody know what size it is?

....one more thing..... watch it on that V6 stuff
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Old Apr 22, 2010 | 04:08 AM
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Originally Posted by 1CL3ANSUP3RSPORT
W/O a tune wouldn't it run to lean,which possible burn up your pistons?
if you are talking about the effects going catless then no, it will make absolutely no difference. However, you do have an after cat O2 sensor that will get angry so it should be shut off or you'll throw a code.

After getting headers you don't have to get a tune but you should.
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Old Apr 22, 2010 | 05:54 AM
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Originally Posted by AlabamaGuy
The average tq is where it's at.

UNDER the curve, people...under the curve.
Exactly.
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Old Apr 22, 2010 | 06:47 AM
  #30  
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Originally Posted by JDMC5
if you are talking about the effects going catless then no, it will make absolutely no difference. However, you do have an after cat O2 sensor that will get angry so it should be shut off or you'll throw a code.

After getting headers you don't have to get a tune but you should.
Alright,thank you sir...
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Old Apr 23, 2010 | 02:44 PM
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Ya i would watch it on the v6 stuff...I have three friends with the v6 and they all run low 12's and they are no where near maxed out. My car is almost completely maxed and i am lucky to get into the 12's.

When i do the install i am getting, inspection, new brakes all around, tranny fluid flush, replacing the cat with a straight pipe, new thermostat, plus the header install. Its going to be expensive. Thats why i am waiting.
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Old Apr 23, 2010 | 06:28 PM
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Originally Posted by JDMC5
I thought they put out 323lbs at the flexplate.

Bare with me because I'm use to the maf and TB being referenced in mm but, I thought the LS4 came with a 78mm TB, if that's the case then it's plenty for what most LS4's will ever see. I'm not sure about the maf though, does anybody know what size it is?

....one more thing..... watch it on that V6 stuff
Dam, it is 323.
It's the O.D of the MAF and TB that determines the pipe dia. So, even though we have a 78mm tb (butterfly) we have dinky tubing compared to other LS motors. Also the intake opening maybe 78mm, but its necked down right after. It's a big pile of junk IMHO. GM, had to compromise between the V8an 4cyl 9DOD) plus they had to design stuff around our exhaust crossover pipe so I have no hard feelings. I still think our MAF is rather small, it just doesn't make since to change it because we can't flow anything more then what the intake will use. All 4.8-6.0 truck motors and LS6's and LS2's have the same type of MAF. They are calibrated differently but they use the same housings which our much bigger then ours.
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Old Apr 23, 2010 | 09:46 PM
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Originally Posted by DavidGXP
Dam, it is 323.
It's the O.D of the MAF and TB that determines the pipe dia. So, even though we have a 78mm tb (butterfly) we have dinky tubing compared to other LS motors. Also the intake opening maybe 78mm, but its necked down right after. It's a big pile of junk IMHO. GM, had to compromise between the V8an 4cyl 9DOD) plus they had to design stuff around our exhaust crossover pipe so I have no hard feelings. I still think our MAF is rather small, it just doesn't make since to change it because we can't flow anything more then what the intake will use. All 4.8-6.0 truck motors and LS6's and LS2's have the same type of MAF. They are calibrated differently but they use the same housings which our much bigger then ours.
Damn that was hard to read...
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Old Apr 23, 2010 | 09:55 PM
  #34  
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where did you pick up the torque under the curve??? close to our stall setting??
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Old Apr 23, 2010 | 11:23 PM
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Originally Posted by GXP25
Damn that was hard to read...
agreed! trust me I know how crappy the LS4 intake is but the TB is plenty big and with a decent air intake your TB- forward should be pretty low restriction. I'm uncertain on the MAF size though. You could always run a mafless setup or a bigger maf but I doubt there would be more than 5hp gains at the 300-350hp level.
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Old Apr 23, 2010 | 11:26 PM
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Originally Posted by Sittingmongoose
Ya i would watch it on the v6 stuff...I have three friends with the v6 and they all run low 12's and they are no where near maxed out. My car is almost completely maxed and i am lucky to get into the 12's.

When i do the install i am getting, inspection, new brakes all around, tranny fluid flush, replacing the cat with a straight pipe, new thermostat, plus the header install. Its going to be expensive. Thats why i am waiting.
you do have all the boltons but your car is by no means maxed out, bigger cam, turbo etc.

You could shave off quite a few buck if you did it yourself.
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Old Apr 23, 2010 | 11:45 PM
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Originally Posted by Bryan921SS
where did you pick up the torque under the curve??? close to our stall setting??
I'm making like 240 something lb-ft at lockup. And it literally gained pretty much everywhere.
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Old Apr 24, 2010 | 07:58 AM
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Originally Posted by DavidGXP
*snip* I still think our MAF is rather small,...
Inner diameter of the LS4 maf is 78mm. I don't think it's the limiting factor.

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Old Apr 24, 2010 | 10:17 AM
  #39  
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Originally Posted by TiredGXP
Inner diameter of the LS4 maf is 78mm. I don't think it's the limiting factor.

Agreed!! I think the main factor is the intake. All by itself it's way to restrictive.
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Old Apr 24, 2010 | 12:23 PM
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The intake and maf arent really restrictions till we start putting a lot more power down. And yes i know a more aggressive cam would help but i wonder how much considering my car didn't respond to the ls6 cam. I want the shop to do it because i know they will do a great job plus i work everyday and cant be without my car for the 4 or 5 days it would require for me and my friends to do it. Also i have a feeling that whole intake crossover issue and welding of the downpipe will require a little more know how than i have.
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