Interest in Custom built 4th gen V8 4.7 Doug Thorley Headers

[cjsmuscle]

Will be keeping an eye on this thread and the 03-04 headers if they are ever a Group Buy!

 

[nivlak]

Can I also make a HUGE suggestion to the rest of the group. The factory Y-pipe is the worst designed y-pipe i have seen. There are a few replacements. I just got a magnaflow replacement and I'll post up the differences hopefully later this week after SEMA is over... But I think this is one of the BIGGEST reasons for the failing headers. So much backpressure at the Y that the exhaust is seriously choked. Also, the factory manifold/header design is trying to force air to make a 90* bend, which causes so much turbulence. This is the reason these headers make extra gains. The ceramic coating helps hold heat in, keeping velocity high, and also helps prevent excessive engine bay temps. You really shouldn't have any concerns for losing the heat shields because of the coating.


2003-2004 V8 headers
1. Tollboothwilley
2. CruzadoBlanco
3.
4.
5.
6.
7.
8.
9.
10.

Add me to the list!

 

[derekdevasia]

Add me to that list too, my headers are so cracked that I failed state inspection for it last year.

 

[JDinh4R]

Add me to that list too!

 

[KaseyMcc]

DAMN IT! It would be months before I have the funds for it the DT headers but I am definitely interested since I started getting the "tick" a couple thousand miles ago.

 

[xcvgi]

Depending on price, absolutely!

 

[theory6]

Can I also make a HUGE suggestion to the rest of the group. The factory Y-pipe is the worst designed y-pipe i have seen. There are a few replacements. I just got a magnaflow replacement and I'll post up the differences hopefully later this week after SEMA is over... But I think this is one of the BIGGEST reasons for the failing headers. So much backpressure at the Y that the exhaust is seriously choked. Also, the factory manifold/header design is trying to force air to make a 90* bend, which causes so much turbulence. This is the reason these headers make extra gains. The ceramic coating helps hold heat in, keeping velocity high, and also helps prevent excessive engine bay temps. You really shouldn't have any concerns for losing the heat shields because of the coating.


2003-2004 V8 headers
1. Tollboothwilley
2. CruzadoBlanco
3.
4.
5.
6.
7.
8.
9.
10.

Add me to the list if you're able to get anything going for the 03-04 V8 4th gens....

 

[isdriven]

My truck has been in the shop since last week getting the headers installed. They took them off last week, I had the cats welded on within a day but got back ordered on gaskets. Gaskets arrived on Saturday and I had all delivered for first thing Monday morning. The shops comments are that the headers are not mechanic friendly. Apparently getting the nuts back on are a real challenge as the tubes are in the way. Hopefully getting the truck back tomorrow for the weekend.

Any update? :naughty:

 

[tollboothwilley]

I have a cracked manifold! Was on the fence on what to do. Sign me up Scotty.

Curious - is it bad for the car to drive with the manifold leak?

With headers cracked it will cause you to use extra fuel - with an increase in fuel you can also foul the catalytic converters. Its not great, but you will be ok for a little while.

 

[tollboothwilley]

Can we use the muffler/resonator of a Tundra 5.7 in our 4.7? I was driving next to one yesterday and i liked the sound. It sound throaty like a truck. I guess we can use an aftermarket muffler as well.
For those that have installed the DT headers, what mufflers did you install?
Are there any exhaust sounds recorded somewhere?

Most people who have the DT headers are not running any different exhaust yet as far as I know. You can use several options, but most will have to be cut/welded in to fit.

Are there dyno results? Does low end torque change?

I am waiting to hear back on dyno info - but am in contact with them. You will most likely have some change in low end torque as the entire RPM band will be changing with exhaust that doesn't have to make a 90* bend. It will be a drastic improvement in almost every way though. I am baffled at why the Toyota designers did what they did on this exhaust.

My truck has been in the shop since last week getting the headers installed. They took them off last week, I had the cats welded on within a day but got back ordered on gaskets. Gaskets arrived on Saturday and I had all delivered for first thing Monday morning. The shops comments are that the headers are not mechanic friendly. Apparently getting the nuts back on are a real challenge as the tubes are in the way. Hopefully getting the truck back tomorrow for the weekend.

Welding in the headers is a tedious process from the normal bolt in process, but they are doing this to retain CARB legality.

I would measure the headers vs OEM and cut the pipe while on the car through the side of the engine. Hold them in place and tack weld the pipes, then remove, fully weld, and bolt them on. This is how I plan to do it. Not easy, but nothing crazy.

No matter what, still a 100% better option than replacing with a factory pipe that is going to keep cracking.

I'm interested in the 03-04 (as long as some kind of cat is retained)! But: it's going to be some time next year before I have the funds... moving is a b$%#h.

DAMN IT! It would be months before I have the funds for it the DT headers but I am definitely interested since I started getting the "tick" a couple thousand miles ago.

DT expects the final product will not be done til around the 1st or 2nd week in Jan - so you have some time.

Will be keeping an eye on this thread and the 03-04 headers if they are ever a Group Buy!

I will be hosting a GB for sure. I know the retail is around $700-750, I think if we have 10+ we will be able to do $100 off or possible even more.

Depending on price, absolutely!

Any update? :naughty:

Talked on the phone with Mike today - he expects that around 45 days til final product is ready. They are not 100% the same as the 05-09 because they have slightly less room. As such, they required a modification to the design slightly. But shouldn't be too far off

 

[tollboothwilley]

Ok - So I have compiled the list people who claim to be interested with a GB

From normal experience, we see about 50% of people who claim to be interested actually participate. The more we have participate, the more the price goes down.

As of yet, we do not have a "final" price point so no way to say exactly how much they will be or have price points. However, Lets just assume a price point of $600 or so for a Group Buy for now.

2003-2004 V8 headers Group Buy Interest List
1. Tollboothwilley
2. CruzadoBlanco
3. the great him
4. sr3tlaw
5. Jagerzel (on the fence)
6. V8Man
7. jp8900
8. Bob J
9. V8Limited4wd
10. wmiranda
11. wracks03s
12. wracks03s (another set)
13. BusinessHippieRH (time frame)
14. nivlak
15. derekdevasia
16. JDinh4R
17. KaseyMcc
18. xcvgi
19. theory6
20.
21.
22.
23.
24.
25.

 

[Mikep.]

I was at SEMA yesterday and ran into Dough Thorley headers. Saw these and had a lengthy discussion with Mike Johnson. They are working currently on the 03-04. I told him I would try to get a group buy set up possibly, if you guys want to do that. It would make it better for all involved. They are hoping to get them done within a week or 2.

I know there are a bunch of 03-04 looking for these. Mike told me that the 03-04 have a bolt in cat, so these would not be a weld-in setup. It would make this an easier install for those who are hesitant due to the welding that the 05-09 require.
Who would be interested in a group buy? We do not know final cost, but we can assume $650-700 is approximate for a group buy price. (Could possibly go a little lower, I'll work with him through my parts business to see about getting the best price)

If ours will be bolt on, I am definitely interested.

 

[JoeG]

If ours will be bolt on, I am definitely interested.

Same here!

 

[stoopid911]

Add me to the 2003-2004 list as well

 

[tc05runner]

So just to be a hundred percent sure, the 05-09 will need to be welded to and existing cat or pipe beyond the header and not bolt on, right ?

 

[isdriven]

So just to be a hundred percent sure, the 05-09 will need to be welded to and existing cat or pipe beyond the header and not bolt on, right ?

That is correct. It is not a bolt on application.

 

[Range]

Add me to the list PLEASE!!!

2003-2004

Did I say add me to the list please?

 

[truckhigh]

i would be interested in the 03-04 v8 in the near future.

 

[kyle_uran]

For around the $600 price point, i'd be interested in 2003 headers. What type of gains would you expect?

 

[Az4runnin]

I am interested as Well for 03-04 GB. Start Saving Now.:dancin: