Any sources for a cat test pipe or is there a 03' GM Part number that would work in place if existing 04.5 LLY Cat ??


Thanks in advance

Its the same pipe used on the LB7. Just no cat.

I had the local GM parts guy doing some checking and he could not confirm that. I'm not doubting you one bit...just need a good GM part number and I can order it myself. How far back does the pipe go on the 03' ? He told me it went all the way to the muffler

Soapy, you can quote me on this: Find a new parts guy. Every duramax, be it lly or lb7 has the down pipe with a flange just after the cross member. If I were you, I wouldn't buy the GM pipe. I'm pretty sure it will cost you a ton. If you wish, I know the Dynomax number bolts right up just like a factory part. THe down pipe is part number 54194. Good luck with whatever you decide

Thanks for the help !! I'll look into the Dynomax #

GM will sell you a test pipe for a truck that came with a cat?

I just put a stock LB7 head pipe off an 02' on mine last night no difference what so every just a pain in the A** to get that dam converter pipe off I'm Going to put Banks on it when I get Time Turbo6600http://www.dieselplace.com/forum/smileys/Approve.gif

GM will sell you a test pipe for a truck that came with a cat?


No. "test pipe" is a euphemism for eliminating a piece of Emission control equipment, supposedly for trouble shooting purposes.....http://www.dieselplace.com/forum/smileys/Ermm.gif


Basically they are just installing front exhaust section without a CAT on vehicles that originally came with one. I believe the LB7 exhaust without a CAT will fit right in where the where the original was on either CAT equipted LB7's or on the LLY's which all have a CAT.


While I've not actually priced a GM supplied front pipe without a CAT, I suspect that as one of the above posts has said, it would be really expensive versus an aftermarket system.

Turbo6600,


Any noticeable difference in performance or EGTs without the CAT on? That Dynomax pipe is only $129 at Summit. Wondering if it's something to add to the birthday wish listhttp://www.dieselplace.com/forum/smileys/Big Smile.gif http://www.dieselplace.com/forum/smileys/Ermm.gif

You can go to almost any muffler shop, buy a piece of 3.5 inch pipe, then cut said kitty out and replace with small tach welds to hold in place then unbolt and weld all the way around. No leaks, works great just like the muffler replacement pipe.

The only bad part about cutting the converter out is if you ever have to have something major done to the truck (i.e. engine replacement, it might become an issue if the dealer wants to make it an issue. From what I've seen and heard modifying the emission system can void your warranty. I have never heard of it happening to someone, but the possibility is there. With my system, the stock exhaust is sitting on standby just in case the unthinkable would happen. Then, before I take it to the dealer, I can slide underneath, unbolt my dynomax system, put the converter back in there, and take it in. That way, the dealer has zero ammunition to void warranty, or surprise me with a large repair bill that I have to pay for. Just a thought....





Scott

There's also the need to re-install the CAT for yearly emission testing in some parts of the Country like where I live. Those of you who don't have diesel emissions testing yet, it's coming....http://www.dieselplace.com/forum/smileys/Dead.gif


Take a look at the recent edict by the EPA regarding, I believe 34 States, says they've got to do more to comply with existing regs. Let alone the new ones they've got in store for us.

Sounds like they are going to start in Weber county next year. Later! Frank

Is that dynomax SS? If not, anyone know where to get a SS "test pipe"? As far as a muffler shop--here in MI we have no emissions--period--but no shop will cut off a CAT!

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<DIV class=indent6> WLK-54194</DIV></TD>
<TD class=cellgry vAlign=top width=*>Pipe Turbo Exhaust 01-03 Silv./Sierra 2500HD/3500 6.6 Duramax</TD>
<TD class=cellgry vAlign=top align=middle width=60>Tomorrow</TD>
<TD class=cellgry vAlign=top width=100>
<DIV class=price>$129.88</DIV></TD></TR></T></TABLE>


the Dynomax setup is not SS, it's aluminumized steel


Above is the Summitracing.com part info

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This is off the Dynomax Website


Dynomax premium turbocharger down pipe #54194 for the 2001-02 Chev / GMC 2500HD /3500 6.6L Duramax diesel Pick-Up, all models, all wheelbases</TD></TR>
<TR>
<TD width="100%" colSpan=2> </TD></TR>
<TR>
<TD vAlign=top width="100%" colSpan=2>
<UL>
<LI>4" OD, mandrel bent, type 409 stainless, 15 gauge tubing.
<LI>Designed to mate directly to a Dynomax performance exhaust system or to the OE exhaust.
<LI>Utilizes the OE hanger location for an easy installation.
<LI>Lowers back pressure at the turbocharger outlet to increase engine power and improve fuel economy.
<LI>Dynomax system kits #19362, 19364, #19365, and #19375 are available to mate with this down pipe.
http://www.dynomax.com/images/54194.gif </LI>[/list]</TD></TR>
<TR>
<TD width="100%" colSpan=2> </TD></TR></T></TABLE>

Hmmmm... seems to conflict w/ what is said on the SummitRacing.com website






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<TD class=cellwht vAlign=top width=*>Exhaust System, Ultra Flo, Turbo Back, Aluminized With Stainless Muffler, Chevy/GMC Duramax Diesel Truck</TD>
<TD class=cellwht vAlign=top align=middle width=60>5-19</TD>
<TD class=cellwht vAlign=top width=100>
<DIV class=price>$346.39<SUP> 2</SUP></DIV></TD>
<TD class=cellwht vAlign=top width=70>
< style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px" =http://store.summitracing.com/left_menu.asp method=post target=leftframe>< = value=add name=>< = value=WLK-19364 name=part>< maxLength=2 size=1 value=1 name=quantity>< title="Click here to add WLK-19364 to your shopping cart." =":this.src='/images/browse_images/add_to_cart_f2.gif';" =image src="http://store.summitracing.com/images/browse_images/add_to_cart.gif" align=middle> /images/browse_images/add_to_wishlist_f2.gif (http://www.summitracing.com/mygarage/default.asp?function=search&amp;part=WLK-19364)</></TD>
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<DIV class=indent6> WLK-19365</DIV></TD>
<TD class=cellgry vAlign=top width=*>Exhaust System, Ultra Flo, Turbo Back, Aluminized With Stainless Muffler, Chevy/GMC Duramax Diesel Truck</TD>
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Mine should be here this week...I'll post the results and what material it is made out of once I get it.....

Mine should be here this week...I'll post the results and what material it is made out of once I get it.....

Just wondering if you got it installed, & if so, what the results are.

here is website page for pipe


http://store.summitracing.com/default.asp?target=search.asp&amp;type=bysummitpart&amp;se archtype=both&amp;part=WLK-54194&amp;x=19&amp;y=14

Late report on Dynomax pipe…. Installation was a breeze taking about an hour in the driveway. You do need to remove the hanging bracket that is mounted on the transmission, but it only has two bolts that hold it in place.

Results: Definitely throatier in the back…. you can hear the turbo noise
while idling if your standing near the rear. Normal driving there
was no difference.

The turbo seems to spool up quicker from a standing start.

There is noticeably more of a “Diesel” smell than with the Cat
on the system. (and yes I know it’s a diesel)

I have not had any check engine lights as noted by some members

The mileage average increased around 1 to 1 ˝ per the DIC

Hope this answers and questions

What exhaust system are you running? Stock 3.5" or aftermarket 4"? Did it contribute additional interior noise at idle, cruise, or WOT?

The pipe I used was the dynomax 4" There is no additional interior noise.

Sorry, I should have been more specific, what are you using from the converter back, stock or aftermarket?

hmm intersting that there isnt a code that pops up with the lack of a cat there. anything that adds more turbo noise is good in my books! http://www.dieselplace.com/forum/smileys/Big Smile.gif

Completely stock witht he exception of the 4" replacement pipe for the cat.

Right now I have a straight pipe where the muffler used to be. I was wanting to put this replacment downpipe where the cat is right now. By taking off both the cat and muffler, would it cause any codes to pop up. I have seen some people who have taken off just there cat, but not the muffler, and I didn't know if it would make a difference by having both off. Would it make it that much louder by not having the cat on there? Thanks for any responses.Edited by: codythom