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1G Twin scroll manifold for twin scroll 18/20g

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OGDSM1989

Proven Member
248
34
Feb 7, 2016
San Antonio, Texas
I have looked a bit on here and google a little less.
I am after a true twin scroll manifold for a 1g that will use a twin scroll 16g modded to either a 18 or 20g. I would prefer that the manifold would be a cast piece ( stock looking ) but a tubular that has twin wastegate ports .... top mount would be cool. This will be for a future build consisting of a destroked 2.4 block around 2.2L running on E-85, 2g head and evo 3 intake mani.

My questions ,

Are there any manifold already in production cast or tubular that fit this or am I looking at a custom build ?
What is a good size wastegate ? ( Those with experience concerning twin scrolls please chime in )
E-85 what woule be a good fuel system to power this kinda setup / ( Never used E-85 )
 
I have read his thread and had exchange with another DSM'er regarding a manifold. Looks like the only way is custom , either using two cast manifold ( evo 3 w/ 1g flange ) or a custom tubular .....so now I am going to make some calls and see if one of these custom shops / fab shop have any ideas on what they can do.
I will get a true twin scroll manifold for my 1g cast or tubular .... I think that for a daily it will yield the best results. Especially a 2.2L 20g ..I would think could see 375-400 hp on E-85.
 
I would see about getting a stock X manifold and having a dsm flange welded on then the holes countersunk/aligned as needed. That would be the most cost effective.

I had the same thoughts as you, cast would retain the spool and longevity. A tubular is way easier, but costs a bit more and would alter spool a little bit. As far as power, I don't see why with a very good setup you couldn't get 425-450. There's a single scroll suby on nasioc with a billet 20g/9 blade turbine making over 400hp, full boost was around 36-3700rpm. With twin scroll and a more efficient IC and cylinder head I don't see why 450 couldnt be achieved.

If u need some parts I have a complete X turbo/mani/o2 I won't be using anymore.
 
94awdcoupe is kinda where the idea came from .... I will send a pm.. I just hoped / wondered if more people had done this and maybe they had some hidden knowledge they would share. I am surprised that not more people wouldnt be interested in this setup ... I mean really a twin scroll 20g, decent spool and air flow and your using Mitsubishi parts. No better sleeper then that as long as it looks factory and not all cobbled together.

I personally would rather run a twin scroll 20g instead of some massive Holset40x , 35R variant .... but I am a little older now and have had my fair share 37R's and other custom built turbos. I want something that can take the kids to saturday local shows, coffee on sundays and maybe a few friday night test and tunes ...... a 20g should do all that and maybe a little more.
 
I am a little older now and have had my fair share 37R's and other custom built turbos. I want something that can take the kids to saturday local shows, coffee on sundays and maybe a few friday night test and tunes ...... a 20g should do all that and maybe a little more.

More people aren't running setups like this because of the cost and effort it takes to do it right. Anything twin scroll on a DSM is going to be a custom job, especially if you're trying to retrofit a 20G to a TS manifold and such. I'm not even sure a 20G TS turbine housing exists.

For the time and effort you'd have tied up in doing a custom 20G TS setup right, you could choose a variety of other turbos that have similar performance characteristics for a fraction of the cost and effort. That is, unless you can do all the machine and fabrication work yourself. In that case, it may be feasible.
 
From what I understand from talking to and reading threads that 94awdcoupe has been contributing to he has been trying to get it a bit more mainstream, or at least show people it can be done without it being a massive headache because the evox setup is similar to our own. In all reality some people reading this post have probably had to do more fabrication trying to get their ebay front mounts to fit right then what would be needed to make this setup work...

The main issue with it is, as it will continue to be for anyone owning a DSM (as pointed out to me a while ago by Brett) is quite simply that it is an out of date platform, If this was an evox turbo going onto a ford focus st? There would already be R+D being done on it if it was this close, those cars are everywhere now, it's the new subaru. Unfortunately it is up to us, the community to push the issue and maybe reach out to one of our vendors and see if it is something they'd be interested in pursuing. If we could do a twinscroll swap and be in it and have a TS20g setup bolt on for around 1500? People would be all over it, I think it'd be the 68hta sale all over again.
 
19gsx91 those are my thought exactly, .... Although sadly GSTwithPSI is correct on the fact that the time and fabrication needed usually outweighs the gains those said FAB shops and Vendors would want to see before even considering making this stuff for us on our dated platforms. DSM ( 85% of us ) are extremely loyal to the brand ... some of us have new new cars / performance cars but still spend our time and money on this platform ( 30% maybe 45% ) out of loyalty. I suppose 30% willing to spend the money while maybe 15%-20% have the money to spend is not enough to get the attention of vendors like BEP, Frontline Fab, etc etc that have the tools and machines necessary to make these kinda parts .... Looks like smashing two manifold together and using take off parts from other more " in the moment" vehicles is the way forward at this point.
 
I still say that there are some vendors,boostin comes to mind first, that if there was enough of a push, with someone providing a base template and a few guinea pig cars we might be able to see something happen. I'd gladly drive my car out to them and let them do R+D on it for a few months if it meant the entire community would see something come of it. that or maybe I'd have a one off twinscroll setup :sneaky: STM is half an hour from my house but I've only ever seen 2 dsms there that didn't belong to people that work there. I'll mention something to Emery next time I see him though.
 
After thinking a little bit last night, I thought why not someone like FP who already has a manifold cast that bolts to our 1g heads and 2g heads ...... so that half the equation is done, next would be designing the twin scroll flange that adapts the new Evo X turbo since they orientated it back the way that ours sits.
I know its not super easy or cheap, but I am guessing that they would a bunch ... their manifold ( just opinion ) is one of the most sought after cast pieces around and I would bet that building a twin scroll cast mani that fits the Evo X turbo would be just the same. They could even design a new cast Evo X mani and reach both platforms.
 
To be blunt, the development costs are simply not going to be recouped by the sales it would bring in. Very few would buy it because it will be more expensive than the other options on the market, and it wouldn't provide enough of a benefit for most buyers to justify the added costs. Too risky for a shop to do all the R&D work only to sell a few of them. Shops like FP and others simply don't spend enough time focusing on this platform anymore - they hardly even visit the forum to answer questions about their own products anymore. It's sad, but that's business. That might create some opportunities for smaller fabricators to step in, but it's still only a small opportunity.
 
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Good point, that's why I suggested going to them with a working design similar to what 94awd had done that way most of the R+D had been solved, but you're right.. It's outdated.. I could still mention something to Emery though as they did just release some new exhaust pieces for a 2g so they haven't completely checked out, he might want to pursue it further, considering how much those guys like to break records. When I see him next I'll ask and see how far it goes, maybe not far.. but it's worth asking right?
 
The biggest issue is going to be the cost vs hp goals that you have for the car and wether what you are using the car for. Twin scroll is great dont get me wrong but is generally overlooked unless you are limited to a certain size turbo for class restrictions.
 
For me it's a "have your cake and eat it too" I'm actually switching from a "new" 68hta back to a 16g because I'm not impressed with the spool time, I love the punch of the turbo but I've got nothing but lag until about 3700rpm, then it's game on. no good if I want to pass someone in 4th doing 50. But I'll be monitoring this thread because I'd really like to see what input some of the more.. home fabrication minded members have to offer.
 
I think an already sorted out setup is a possibility for a vendor, but even then, it's not the hardest or most expensive thing in the world to do, and if you have to have it, just get the parts and do it.

This manifold ($350)
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With a dsm flange ($30-$100)welded in place of the X flange, and you get a sub $1k equal length twin scroll td05 based setup. even factoring in cost of a new hotside (~$350-400) you'd be sub $1500 for a damn nice 20g setup that should spool like a banshee and make some awesome numbers, especially on e85 or race gas.
 
So the concept of having a twinscroll manifold is to separate the exhaust gasses from the other cylinders that are going to interfere with each other. So the only way this is going to benefit you is if you have an twinscroll turbine housing.
 
The good news is that there's a lot of evo guys that are ditching they're "smaller" twinscroll turbos to upgrade so it could become a viable upgrade if the conversion was ever figured out, if any of us watch the evo forums, I'm sure they're just as active, if not more so then we are.
 
There are a lot of options when it comes to twinscroll housings but what are you trying to achieve? Fast spool? big power?
 
I think what the OP is after is just a twinscroll swap, to be put simply, a fast spooling (sub3500rpm I'd assume) hard hitting (Think 20g/FPgreen territory) setup, the fabrication isn't out of this world as it's been done before, we keep bringing him up but I feel like If we mention 94awdcoupe enough he'll finally chime in,

I think he just wants to know what's all involved. Chris and Brett are correct in saying that with us being an outdated platform there won't be any aftermarket support, but tametalon provided at least one answer to the OPs question, buy a tubuluar manifold and swap the flange for a dsm. We are kinda straying off into some grey area though now that I re-read OPs original post, and to OG sorry for the detour the thread took.
 
If youre running a tubular manifold with a dsm flange on a single scroll housing... you have stepped away from the twin scroll conversation and now are strictly talking about what tubular manifold will reap the biggest rewards for quick spool. In that case, probably whatever one has the shortest runners.
So you are now back to a cast manifold from FP or evo3. the evo manifold has a more pronounced divider than the fp at the collector, so that would be the closest to a twin scroll manifold LOL.

UNLESS the point was that a twin scroll turbine housing was somehow sourced and the options of manifolds was now in scope. in which case, just cut off thr flange of whatever tubular it is that you have, and have a dsm based one made that matches the inlet divider of the new housing.
however you are sacrificing inlet area on the divider itself, so that now becomes a negative for ultimate flow capability. the dsm flange bolt pattern is only capable of permitting a certain inlet area.

as is, money will likely have to be of no consequence for this ride to end.
 
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The biggest issue is going to be the cost vs hp goals that you have for the car and wether what you are using the car for. Twin scroll is great dont get me wrong but is generally overlooked unless you are limited to a certain size turbo for class restrictions.

Cost vs HP is assuming that everyone is looking or chasing HP. Yes more HP is the a portion of the reason for doing an upgrade like this, but its not the driving factor. For me its really more about having a newer OEM part that also comes with some extra HP, driveability , more useable torque and HP curve then a standard "old" 16g .... stock appearing "sleeper" status.

No worries about the detour, sometimes detours lead us to the exact place we wanted be ... sub 3500rpm would be awesome for something like a Green but I really like to use Mitsu OEM parts. The tubular manifold is not out of the question as Curt was eluding too ... and I always sadly agree that our "outdated' platform gets us very little support from vendors.

Tametalon posted a great tubular manifold that uses the Evo X turbo which is in the ballpark of what I am after ... why not just use the Evo X turbo on here and the turbo built into a 20g ? I thought the Evo X turbo was a twin scroll ? .. If not what housing is twin scroll and how small or close to a 20g can I get ... using CHRA ?
 
It you want TS so badly, delete ac, power steering and relocate the alternator. After that you can bolt up a stock evo setup. Easiest and cheapest way to do it.
 
I'm getting confused, because that's what I was alluding to the entire time, making an evox based TWINSCROLL setup work on a 1g, thus the suggestion of taking the TWINSCROLL manifold and putting a dsm flange on it and bolting an evo twinscroll turbo and then having some sort of custom downpipe... I feel like some of the guys didn't read this thoroughly. Yes.. the evox turbo is indeed a twin scroll and everything is set up fairly simliar to how dsms are from what i've read and seen, without the need for all the relocation that lasthope suggested. I guess the only way to do it is to try right?

Not trying to come off as rude but I'm not really sure everyone's on the same page..
 
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