That makes sense. So my next question is, why not stainless? :P I don't doubt that the SCH40 steel will hold up really well considering the rather weak EGTs of a piston engine compared to a rotary, but in bulk the supplies in stainless aren't much more than mild steel. Of course it requires much more fussy welding.

And why stainless for the intercooler piping instead of the much lighter aluminum? I used to make mine with stainless before I had the equipment to weld aluminum.

Hope it doesn't sound like I'm picking you apart...I just want to understand your decisions.

What EMS are you going to run?

 

Nice work, keep the updates coming!

 

I like to use low carbon steel for turbo manifolds because when you weld it the heat affected zone (HAZ) has composition that's very similar to the base metal, therefore the weld has a very similar grain structure to the base metal grain structure. This is because there isn't enough carbon or other alloys to form brittle crystalline structures. Stainless on the other hand will rapidly form brittle crystalline structures at the HAZ. Even though stainless has better creep resistance than low carbon steel, if you consider in the composition at the HAZ, the low carbon steel welds have better creep resistance than stainless welds. You'll notice most properly welded stainless manifolds will crack in the HAZ. (If they crack in the center line of the weld, that is just a bad weld -- wrong filler, little penetration)

Other minor reasons are low carbon steel expands less than stainless steel, don't need to back purge low carbon steel, low carbon steel warps less than stainless steel (not only when welding, but during service too).

You are right, stainless steel weld elbows cost about $1 more than steel in bulk. So cost really isn't a factor.

Ideally, the ULTIMATE manifold would be thick cast stainless steel! I'm planning to make a kit out of this if this works out well in the future. When I get to that point, I will definitely be making cast stainless manifolds because the cost will be justified, the setup well be proven, and there will be no welds to crack


I used to make aluminum intercooler piping before. You're right its lighter. For my current setup, it'd be about 6lb lighter. Aluminum on the other hand is absolutely garbage in terms of being scratch resistant! After a couple times removing the piping in and out of the car, they'd be scratched easily. **** even putting them on the work bench meant they'd get scratched! I can throw my stainless pipes onto the table, across the room (don't ask me why), and they don't get scratched or dented. Another reason is cost. I can get stainless mandrel bends for a lot cheaper than aluminum mandrel bends. $13 vs $22 on average. So it costs less, looks better (yes I've got ricer tendencies hehe), and weighs slightly more -- this is why i use stainless over aluminum.

 

Man, that car was looking good tonight. Nice work Zeeshan

Subscribed.

You me and Ken need to get together for drinks at your place

 

I agree, welding stainless can be very easy to get wrong. Controlling heat and keeping the oxygen away will go a long way to help carbon embrittlement but of course the only fix is to anneal the whole manifold after. Not exactly a practical measure for most people.

That will be very impressive. I don't know anyone making a cast stainless manifold in the rotary world.

 

sounds good matt!

 

intercooler pipes welded!







spacing between the weld puddles is in an effort to save filler and gas :P

 

bead rolled the intercooler pipes

 

Bead roller....*drool*

 

aaron if you need your ic pipes beaded you can come use it

 

so beautiful.

 

downpipe coming together slowly. still gotta recirculate the wastegate dumps. thanks to my buddy brian for helping me out major under the car.
right side setup:


left side setup:

 

 

Zee that looks awesome!! Ill definitely swing by this week

 

Nice work Zee!

Ken, let me know when you're going to swing by and I'll come join you guys.

 

Dual turbos

 

This things come a long way from when I saw it last winter. Great work man keep it up. Ill have to come check it out too