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Headers & Cats installed

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
After buying the D3 headers & cats last spring, I finally got them installed... Initially I thought I'd take them to a shop to get installed, but I decided to tackle them myself.

It was a huge pain! :)

I got one side in over a weekend, and it took a couple of trips to the store to get the right tools. But the other side went on in about 3 hours without a problem.

I ended up doing it on a set of four jackstands and without having to lower the engine cradle. (the service manual states you can only do this by lowering the entire engine - which is why I thought I wanted to take it in to get done)

The exhaust note has changed a bit, but not a huge amount... I have a rough tune that was done for my by Wait4me but it'll be going in to Hennessey for dyno-tune when I get a chance in the next few weeks. I'll post the final dyno numbers with all my mods then.

Photos follow:











 

Popbigguy

Seasoned Member
Joined
Oct 17, 2008
Messages
705
Location
Lincoln, NE
My XLR/V(s)
2007 XLR-V RII'07 RIII'08 SA'09 CO'10 NCSC'11 PA'12 BG'13 MT'14 VBOBX'15
What do you have in after the "cats" now??
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
What do you have in after the "cats" now??

just the stock exhaust... I like the dual-mode sound... quiet for everyday, loud when I turn on the bypass... and with the headers, its definitely loud when the baffles are open. :)
 

Cadillac Tech

Seasoned Member
Joined
Oct 16, 2008
Messages
3,843
Location
Cicero,Indiana
Those are beautiful headers! Great job installing them yourself...very tough job.
 

onalaska

Seasoned Member
Joined
Jul 7, 2009
Messages
533
Location
Coldspring, Tx
My XLR/V(s)
2006 Infared XLR-V
Richard, that looks like a project. I also read in the service manual where it said "remove powertrain" to replace the exhaust manifolds. I couldn't believe it, but then found the process involved to remove the powertrain and basically you lift the body off the powertrain. Wow! Glad to hear there is another way to do it.
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
Richard, that looks like a project. I also read in the service manual where it said "remove powertrain" to replace the exhaust manifolds. I couldn't believe it, but then found the process involved to remove the powertrain and basically you lift the body off the powertrain. Wow! Glad to hear there is another way to do it.

Ya - it looks like GM started doing that back with the F-body cars (firebird/camaro) and saw how you lift the car off the engine and its cradle... doesn't sound like fun - which is why I didnt' think you'd be able to do the manifold/header swap with the engine in place... but alas, I learned you can! :)
 
A

Animate

Guest
Even the stock system looks like it would flow well. Did you happen to weigh new vs old?
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
Even the stock system looks like it would flow well. Did you happen to weigh new vs old?

I didn't weigh them, but the stock manifold was much heavier - maybe twice?

Don't forget that the new headers also had high-flow cats.

It also changed the sound of the exhaust.
 
5

556393

Guest
new exhaust

What tools did you have to buy in order to replace he exhaust? Did you notice a difference in horsepower? Are you willing to say what you did to replace the manifolds? Thanks, from a fellow knucklebuster.
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
What tools did you have to buy in order to replace he exhaust? Did you notice a difference in horsepower? Are you willing to say what you did to replace the manifolds? Thanks, from a fellow knucklebuster.

simple hand tools... yes... I just replaced them - there's nothing to say - unbolt and they come out.
 

WVsunnydays

Active Member
Joined
Apr 27, 2014
Messages
27
Location
North Canton, Ohio
My XLR/V(s)
2006 platinum XLR-V
Thanks for your write up?

After buying the D3 headers & cats last spring, I finally got them installed... Initially I thought I'd take them to a shop to get installed, but I decided to tackle them myself.

It was a huge pain! :)

I got one side in over a weekend, and it took a couple of trips to the store to get the right tools. But the other side went on in about 3 hours without a problem.

I ended up doing it on a set of four jackstands and without having to lower the engine cradle. (the service manual states you can only do this by lowering the entire engine - which is why I thought I wanted to take it in to get done)

The exhaust note has changed a bit, but not a huge amount... I have a rough tune that was done for my by Wait4me but it'll be going in to Hennessey for dyno-tune when I get a chance in the next few weeks. I'll post the final dyno numbers with all my mods then.

Photos follow:











I really appreciate your sharing this information with us other "V" owners. Your write up has been a Godsend for me. I have wanted to put a header exhaust on my 2006 XLR-V for quite a while but wasn't sure such an animal even existed. I e-mailed D3 but they never responded. I will call them now after reading your post. Do you have your Dyno tuning results yet? I would be very interested to see if the headers add any appreciable HP.

Do you still have your stock exhaust on your "V" or does it have a Corsa? I already have installed a Corsa exhaust and a Volant CAI on my 2006 "V".
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
I really appreciate your sharing this information with us other "V" owners. Your write up has been a Godsend for me. I have wanted to put a header exhaust on my 2006 XLR-V for quite a while but wasn't sure such an animal even existed. I e-mailed D3 but they never responded. I will call them now after reading your post. Do you have your Dyno tuning results yet? I would be very interested to see if the headers add any appreciable HP.

Do you still have your stock exhaust on your "V" or does it have a Corsa? I already have installed a Corsa exhaust and a Volant CAI on my 2006 "V".

I didn't end up getting a dyno run done for just the headers... many mods and many runs later I can't tell which mod provided what amount of power change.... at the time I was also struggling with some engine problems that was giving us false readings (vacuum, leaks, etc)

I have found that contacting D3 via phone is often better than email - their email box tends to get over run so lots of messages get forgotten

In the end, I put a corsa exhaust on it.... i'll say that its pretty loud - its quiet when cruising without any drone but when you get on it the exhaust trumpets pretty loudly

Good luck with your mods!
 

WVsunnydays

Active Member
Joined
Apr 27, 2014
Messages
27
Location
North Canton, Ohio
My XLR/V(s)
2006 platinum XLR-V
Dino results

I didn't end up getting a dyno run done for just the headers... many mods and many runs later I can't tell which mod provided what amount of power change.... at the time I was also struggling with some engine problems that was giving us false readings (vacuum, leaks, etc)

I have found that contacting D3 via phone is often better than email - their email box tends to get over run so lots of messages get forgotten

In the end, I put a corsa exhaust on it.... i'll say that its pretty loud - its quiet when cruising without any drone but when you get on it the exhaust trumpets pretty loudly

Good luck with your mods!

Would you be willing to share your dyno tuning results for your XLR-V as it is currently set up?
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
Would you be willing to share your dyno tuning results for your XLR-V as it is currently set up?

I think the last time I had it dyno'ed was about 3 years ago and it put down 399 - which was totally wrong... since then I found a clogged cat, a vacuum leak, a mis-programmed blower bypass, etc... so I need to get it done again but haven't had the time... I tried to go this past Saturday but it was pouring rain
 

hdduane

Seasoned Member
Joined
Jan 15, 2015
Messages
59
Location
Tucson, AZ
My XLR/V(s)
2004 Black Raven XLR
I tried to goggle xlr headers today and could only find some made by magnaflow. Has anyone have any experience using the magnaflow headers? :dunno:
 

XLRVette

Member
Joined
Dec 21, 2013
Messages
18
Location
Vancouver, BC
My XLR/V(s)
2008 XLR-V infra-red/ebony
Magnaflow headers

I tried to goggle xlr headers today and could only find some made by magnaflow. Has anyone have any experience using the magnaflow headers? :dunno:
hi hdduane I bought my 08 v with new magna flow headers and exhaust` looks and sounds great
 

richardyoo

Seasoned Member
Joined
Jan 1, 2009
Messages
308
Location
Houston, TX
My XLR/V(s)
2006 Silver XLR-V
hi hdduane I bought my 08 v with new magna flow headers and exhaust` looks and sounds great

Do you have a photo of the magna flow headers? What do they look like?
 

WVsunnydays

Active Member
Joined
Apr 27, 2014
Messages
27
Location
North Canton, Ohio
My XLR/V(s)
2006 platinum XLR-V
Are The Headers Worth The Cost?

Richard, I've followed this thread with interest for about a year now hoping to learn whether or not putting long tube headers on my XLR-V would be worth the cost and effort. I've been waiting to see what your dyno results showed for RWHP boost due to installing the D3 headers, but alas, nothing has been posted.

FYI, I called D3 on 4/23/15 and ordered the headers with high flow cats for $1995. They said the headers were discontinued but they would be making a run early in the summer of 2015 and took my order. I waited and heard nothing. When I finally called them in June, they said they could no longer get the high flow CATS, and, oops, the headers would cost $2500 now if I wanted them. I have other options at significantly lower cost now.

So, back to my original question, are the headers worth the cost and effort? If the headers only add 10 RWHP, which is what my dyno engineer says, that is pretty expensive. What say you?
 

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