4th Gen V8 - Which First, manifolds or Catback?

[JGardner]

Hi all, I think I've done a pretty exhaustive (pun intended) search and while there's plenty of advice on either subject, I don't have the budget today to do both.

I'm fairly certain that i do indeed have a cracked manifold so am planning on replacing with the Doug Thorley shorty's that are now being produced. The tick is fairly pronounced upon a cold start but pretty quickly dissipates. The rest of the exhaust is also fairly rough and rusted through between the muffler and resonator / tailpipe.

My first inclination is to fix the exhaust manifolds, but between the manifold cost and the installation it's going to be expensive. I'm fairly mechanically inclined, but with how tight everything is around the headers and the potential of breaking a stud, I'd rather pay someone to do the work.

My argument for doing the catback first is that i'm not yet getting any exhaust errors due to failing cats. I've got 230k so I wouldn't be surprised if they show up sooner or later, but I figure why replace them if its not necessary? I am also fairly confident that i can do the cat-back work myself.

Any thoughts supporting one direction or the other would be greatly appreciated.

Thanks!

J

 

[Range]

What year 4th Gen do you have?

 

[JGardner]

Sorry, I should update my signature. It's a 2005 Limited

 

[t-man]

Can you pay someone to do the manifolds and then do the rest by yourself? It is pretty easy once you get away from the motor. If not, do the cat-back first. Mine ticks like crazy all the time and doesn't cause any codes yet. just drives me nuts....

 

[Range]

Correct me if I am wrong but isn't the early 4th Gen V8's something that DT did not make exhaust manifolds and/or headers for? I've looked everywhere for a place that will do headers. Mine is a 2004 but seeing that yours is a 2005 which I think is the VVTi the situation may be different?

 

[KrazedJD]

I have been looking at this, and hate that there are options. Are you in a state that you can do the mid pipes, pretty sure it will mess up the computers emissions checks.

 

[t-man]

Correct me if I am wrong but isn't the early 4th Gen V8's something that DT did not make exhaust manifolds and/or headers for? I've looked everywhere for a place that will do headers. Mine is a 2004 but seeing that yours is a 2005 which I think is the VVTi the situation may be different?

05-09 V8 are vvt-i

 

[JGardner]

I have been looking at this, and hate that there are options. Are you in a state that you can do the mid pipes, pretty sure it will mess up the computers emissions checks.

Unsure what exactly you mean by mid pipes. If you're talking about removing the cats and not replacing it's not something I am overly interested in. If and when I get the Thorleys I'll probably go with high flow cats.

 

[JGardner]

Correct me if I am wrong but isn't the early 4th Gen V8's something that DT did not make exhaust manifolds and/or headers for? I've looked everywhere for a place that will do headers. Mine is a 2004 but seeing that yours is a 2005 which I think is the VVTi the situation may be different?

The DT Shorties are a relatively new option, but only for the VVTi (2005-09).

Here's a link to the manufacturer page: Doug Thorley THY-563-SS-C, | Doug Thorley

And to a pretty big thread about how they came to be and who is using them: http://www.toyota-4runner.org/4th-gen-t4rs/108131-interest-custom-built-4th-gen-v8-4-7-doug-thorley-headers-18.html#post1897984

 

[Range]

The DT Shorties are a relatively new option, but only for the VVTi (2005-09).

Here's a link to the manufacturer page: Doug Thorley THY-563-SS-C, | Doug Thorley

And to a pretty big thread about how they came to be and who is using them: http://www.toyota-4runner.org/4th-gen-t4rs/108131-interest-custom-built-4th-gen-v8-4-7-doug-thorley-headers-18.html#post1897984

Yeah I've read that damn thread way too many times hoping DT would come on and say "ok, we've decided to do 2003-2004 V8 headers"

 

[JGardner]

I can absolutely understand that hope and the frustration of not having options

 

[the great him]

Yeah I've read that damn thread way too many times hoping DT would come on and say "ok, we've decided to do 2003-2004 V8 headers"

these can be used on the 03-04 one if im not mistaken, you just have to block off the secondary air ports... i could be wrong but i believe that is all that is needed.

 

[t-man]

I believe, but could be wrong, you could cut off the part of the flange with the air injection and put it right on your 03-04. Some bolt pattern.

 

[JGardner]

Lots of talk about the headers / manifolds. Good to see the interest!

Any more thoughts on doing the headers or a catback first?