View Full Version : cast manifolds are steel headers for turbo?

06-06-2005, 06:29 AM
Well for now I've dropped the idea of doing a twin turbo system on this car. Mostly due to p[ackaging concerns.

Here's where I'm at as of now. I'll be running a Garrett GT42 located in the upper passenger-side corner where the battery is/was. I have to option for charge pipes. I can either fabricate tube-style headers that curve upwards and bring the dirvers side charge pipe in front of the engine to the turbo flange. Or I can run a stock Ram Air IV cast manifold and bring the charge pipe under the engine and up towards the turbo flange.

Now I've heard from different camps on the benefits or a header over a cast manifold and vis-versa. The cast manifold does not loose heat like the header which is good for spool characteristics and they are generally very tough.

On the other hand, header style would flow quite a bit more air out of the cylinders effecting back pressure. You can run a little bit more aggressive cam profile with this design.

What's everyone's opinion on these two different setups? Any ideas or suggestions would be great.

06-07-2005, 09:07 AM
Tube headers look better, normally perform better, and if sized correctly you should not notice a difference in spool up. Get them coated if you are worried about escaping heat(inside and out).

06-07-2005, 10:40 AM
FYI if youre thinking of making turbo headers out of mild steel tubing they will not last very long unless you use weld L's (weld L's=heavy steel pipe) and even coated the thin wall mild steel tubing breaks down from the heat (BTDT). If youre making headers out of stainless you'll be fine as long as the welds are good and the design of the headers can support the weight of the turbo (lotsa complaints of cracked headers from ppl with off the shelf SS headers).

SS not only tolerates the heat but is a lot less thermally conductive than mild steel so if you have them coated SS helps with under hood heat.

Cast manifolds have been proven at the drag strip to go mid 10s in a 3500lb vehicle and are about as durable as a rock but they are heavy and look horrible if the rest of the under hood area is nicely done. Bascially they kinda stick out like a sore thumb on a nicely done car IMO. However if you use cast iron manifolds for a turbo application your worries of heat damage and structural strength are minimal which makes them attractive if you arent after every last 1/10th of a second in ET and just want to drive the car worry free.

My .02

06-07-2005, 02:10 PM
If i go tueb style header it will most definitely be created from heavy guage stainless steel. I've witnessed kits' build from mild guage steel fall abart rather quickly.

06-07-2005, 06:04 PM
Here is how I have done my 69 Camaro so far. I must have walked 5 miles around the front of my car trying to figure out how I was going to package everything. I used 16 gage 304 1 5/8" stainless for the headers. I also made a mount for the turbo that attaches to the alternator mount and is braced down to the fuel pump block off plate. The turbo is a GT42R and although I have not weighed it, it must be in the neighborhood of 35 to 40 lbs.. I wouldn't even think about installing it without some kind of mount or bracing.

Anyway, I hope this gives you some ideas.


06-07-2005, 11:50 PM
can you explain your wastegate placement??? it appears to be on the exhaust side of the turbo...how would that work??

see pic for the manifold I have/will be using....simplifies installation a lot (I hope)

06-08-2005, 09:51 AM
The wastegate will stay approximately where you see it in the photo. There will be a 1 3/4" pipe coming off above the flange where the 2- 2 1/2" pipes come together. I have a double slip joint that will be welded to the v-band flange on the inlet to the wastegate.

I posted int the Welcome section and was asked the same thing. There is more info on my car there.


06-08-2005, 10:34 AM
ah...that clears it up! Only thing I forgot to say is: nice install !!

I don't read the welcome section much (sorry)...I have so many posts to read each day I have to skip some things.......

but keep us posted on your project Tim.....


06-08-2005, 07:08 PM
TTR installation and packaging wise your route might actually be the best for my situation. The poncho heads have exhaust ports that angle down towards the ground at almost 45*. This is causing packaging issues, especially with the brake booster on the drivers side. I think your packaging may be a solution.