Just curious what's the collective experience with welded tubular manifolds around here? So far the only advice I'm reading is its not a matter of if they crack, but when. Can anybody help me understand approximately when? How big of impact does material choice have? (i.e. mild vs. stainless)

These are the manifolds I had in mind:
ETD shorty
BEGi S4
TurboTim/Shore Motorsports special link

I've got a big ol' GT3071R and I am concerned about spool and response. I'd like a 300HP daily driver that I can take to the track a few times a year. The ETD Shorty is praised around here in the spool/flow dept and appears to be treating eliminator77 (a.k.a. Mr 50 trim record over at m.net) very well.

I am trying to understand the spool/responsiveness versus reliability trade off compared with a cast iron manifold like BEGi's S5.

 

The thick wall tubular manifolds seem to hold up rather well. I have seen my work come back over a year later even in mild steel in remarkably good shape. Depends on the manifold, some have problems, but you find out pretty quickly when that is the case.

Mark

 

I haven't had any issues with any of my manifolds, I'm sure the ETD and BEGI stuff is top notch too. I really don't think a thick wall manifold is going to give you issues if welded correctly. I use schedule 40 pieces, not sure about ETD, I think they are schedule 10 (a little thinner). The next one I do may be schedule 10 to save weight and cut down on cutoff wheels.

 

like tim and mark said, as long as its done properly you should not have any problems with a tubular mani, even if you use schedule 10

 

I think the debate is still open on mild lasting longer than stainless in terms of cracking over time. I can't find the hard evidence though. Someone get a twin turbo V motor and put one of each on it.

I've had my mild tubular ETD mani on for 3 years and many miles and it's been ... invisible. I think it's sch 10 (.109 wall). for reference sch 40 is .140ish and 14 gauge is about .075".

 

My schd 40 top-mount manifold is holding together fine, granted it hasn't seen many miles yet.

 

Good to hear, but want to double check 'cause I'm getting the impression that these manifolds are dead nuts reliable.

So you guys are basically telling me that short of some quickly apparent manufacturing defect, I can subject the manifolds listed above to daily driving heat cycles, plus the extreme heat cylces from several all day track sessions (per year) and expect it to last as long as my turbo?


PS: I can't weld.

 

We do not yet know the longevity of the S4 manifold. It has been put thru the wringer on the street and dyno, but not on the track. We do have a customer who is building a track car with a S4 manifold, so we should know more about track reliability at a later date. To compensate for the unknown we have a two year warranty on the S4 manifold.

Durability and longevity will also depend upon how it is mounted. We mount ours with a support brace for a variety of reasons. 1. support 2. reduce vibration 3. reduce the likelihood of cracks. I do not know that I would expect it to last as long as the turbo. I would hope so, but reality may be different.

Stephanie

 

lol. I guess that bit about lasting as long as the turbo was a tad much wasn't it? But is five hard years too much to expect from a well made unit?

Also, what kind of impact on spool and response should I expect? That's my primary reason for considering a tubular manifold design given the large lazy turbine I've purchased.

 

We have had a couple running for 1.5 years. So far, so good. Is three or five years plausible? Probably.

We have found with the S4 manifold that the low end torque is so good, that the boost at the top end likes to spike. Hence the need for an external wastegate. So far, most dyno sheets of the S4 are more linear (like a supercharger). Which is nice.
Stephanie