I love the sequential setup and would like to stick with it. However, that cast iron manifold sucks and the turbos suck. So I had a thought (and I know it won't be a cheap project) has anyone tried having a new manifold machined out of stainless steel? Not only would it be lighter, it could be machined to hold bigger and better (like ball bearing) turbos, especially for the secondary. A larger wastegate could also be machined into it. And you could still maintain the sequential setup. I understand this would involve a good deal of R&D but I think it would be worth it.

 

why not just cut pipe sections and a flange from Inconel instead?

 

I know SS is expensive, but isn't Inconel really, really expensive?

 

yeah... but you're talking about machining from a solid billet of SS... that's not gonna cheap either. you have to buy a huge block of material and then the machine time (precision=expensive) and all. you could probably do it better and cheaper by shaping some SS piping together properly w/ flanges and all because yes... the cast one = teh sucks

 

I can't imagine how long it would take (= $$$) to machine a SS manifold from a solid piece. You'd probably be looking at $7-10K by the time your done...

 

like this?
http://cgi.ebay.com/ebaymotors/ws/eB...category=33631

 

Ya, I'm not saying it has to be from a solid piece, I'm just wondering if anyone else has made a manifold that can maintain the sequential setup. If not, throw me some ideas, because 7-10k is too much, less than a couple grand would be better.

 

For a sequential set-up utilizing bigger turbos, the entire passenger side engine bay would have to be altered. Plus with bigger sequential twins, the Y-Pipe would have to be redesigned to fit the twins. Bigger twins would probably mean a larger IC would have to be used to achieve proper boost pressure capability. Too much $$$. Much easier to upgrade to Single Turbo.

 

that looks purdy... but i think i'll just wait and go single

 

New IC pipes, bigger IC, and all the rest of the stuff people usually do when upgrading to single would obvisouly have to be done. But pipe bending isn't that big of a deal. I restored a '53 chevy from the ground up last year, and I work on cars everyday. I understand how much work would be involved with this kind of project. I just have no idea how to go about the manifold.

 

this will work with a downpipe???

 

wouldnt just heat treating the origional manifold keep it from cracking? I am assuming the cracks develop from it baking and the pressure.

 

ist the heating, cooling reheating cooling cycle that gets its... you actually are "heat treating" it just by running your car. the material eventually reaches a fatique point and starts to fail.

 

It's not just cracking, that cast iron log is kind of heavy.

edit-I don't see how you could run sequential on that ebay manifold, I guess you could run parallel, but the plumbing would be a mess.

 

is that a manifold for the factory twins? I looks just like the ones for a single setup

 

GoRacer had a thread a while back about this kind of deal. Don't feel like searching for it

 

I found this http://www.re-amemiya.co.jp/new_part...w_fd_mani.html

And that's cool, but I'm talking about the turbo manifold itself.

 

just do this
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/joy-elation-prototyping-independent-twins-%5Bpics%5D-341531/

 

thats not even close to sequential. this entire idea is close to impossible and if it were done would cost 3 or 4 times what it would to upgrade to a single ball bearing turbo. That ebay manifold is the obx ssautochrome one for a single. That seller has no clue. that RE A manifold is for non seq.

 

but it will give you the low end of the sequential.

 

Honda...what makes you say that? What makes that setup spool any faster than non seq twins? It will absolutely not be as quick spooling as stock twins. I am sitting five feet away from 4 of those garrett T25s that he is using. I am half way through that exact setup myself and have done all the research.

 

actually if you make it with GT25R then it might be as good.

 

I agree

 

Here it is: https://www.rx7club.com/showthread.p...turbo+manifold

Oh and Neal, the issue isn't just the weight and heat etc...it's that the stock exhaust manifold is VERY restrictive. That's why you can never really make more than 400some odd hp off our twins, even tho it's long been held that they're capable of flowing more...simply because the manifold is so restrictive.

Look at the Supra twins...sure, it's a piston engine, and a V6 at that, but still, the twins on the Supra are SMALLER than ours, and they can make right about 500hp on 'em, simply because the exhaust manifold was designed so incredibly well as to create the absolute minimum turbulence and backpressure. Ours sucks, period. Also, since hp is torque * rpm / 5252, to get large hp, you gotta make lots of torque at high rpm. Prob is, on our stock UIM, you hit a nice flow restriction at right about 6250 - 6500 rpm. So, to say it simply, our exhaust system as a whole isn't designed to support making such large #s.

To date, no one has made a custom exhaust manifold for the sequential twins to really see just how much our turbos can flow...but Demetrious has a custom UIM if I'm not mistaken, which explains his beautiful torque curve...

 

I wasnt talking about anything performance wise, I was refering to durability. I have never heard of a seq setup that uses a aftermarket set up. I do know that FEED makes a non-seq SS manifold for twins. Someone was selling one in the classified section a while ago. Id be down for a seq manifold but the problem is you would have to have a die hard seq group to purchase it because otherwise people would just go single.