3 1/2 thdp

[et10sec]

has any modified a terry houston 3 1/2dp to fit after market headers? like kenne bell or atr headers.

 

[Louie L.]

It will not work with out hacking the heck out of the THDP. BTDT If you have a good fab/welding shop then anything is possible.

 

[John Wilde]

Originally posted by Louie L.
It will not work with out hacking the heck out of the THDP. BTDT If you have a good fab/welding shop then anything is possible.

If you have a good fab shop make the down pipe yourself.
It is to expensive to pay twice for the same work.

 

[mec108]

I can't belive that no one mass produce a 3.5 or larger down pipe to fit cars with atr/kb headers? GOD.... if I only had the skill to do it I could only imagine the amount of side money I could make? :

 

[ttypewhite]

3.5" DP are not that common. Just the guys with seriously fast cars run them(low 10s and faster). Making it fit with the heater box still in the car is a pain in the a s s. Without the heater box there, skys the limit, there is more then enough space.

 

[Russ Merritt]

With the heater box still there, just not enough room. Cotton jr and I ripped out my heater box and fabbed up a stainless 3.5 DP. While we were doing it, it didn't look possible to build it around the ATR headers with the box still there.

 

[mec108]

Question; My car has atr headers but no heater box. How bad do I have to" BUTCHER" the thdp to make it fit? Any recmmendations. THANKS

 

[Louie L.]

Ill give ya an example on fit. TSM racer Keith Egan ran several turbos this year. Both times the 3.5 in DP fit differently. Not because of the down pipe but the turbo flange differences. Hes had to cut the pipe and reweld. I had to clearance mine around the frame area. i never ran an AC box with it.

In other words , its a quality piece and it fits very well for how large it is. But lots of things will go into the fit of it in any one specific car. Motor mounts, body bushings, turbo mounting flange thickness..yad yada..

These problems occur with a 3 in DP but are not as amplified as with the larger. Now you ad the large collector area and crossover used with ATR headers, things get even tighter.

At this point you are better of building your own. I built a 3.5 out of mild steel as a template for a stainless unit i will some day build. So far the home made DP has done rather well so i dont wanna mess with it.

 

[JCotton]

We've modded the THDP to fit the ATR headers without too much trouble. Couple of cut and rewelds and they fit ok, with or without the heater box. We have actually made several DP's from scratch but do it with the car at the shop, or with the customer sending us their DS header and turbo. We only do it with external wastegates and no heater box cars.