I have just finished the piping for the twin scroll.

I am waiting for the flange should be here tomorrow.

I haven't decided yet whether or not merge the wastegate or just come off one tube. I will try using one tube first then if it doesn't slow the turbo down enough I'll tie both in. Thoughts??

I am building this on my 83 then transferring everything over to the 86 when done.

I will be going from a T4 .58 hotside to a .48 divided housing (very close to T3 .82)


I was worried about the downpipe but 3" fits through just fine

I don't have good camera (ha for those who have seen my other pics) here so these are just phone pics.

 

Looks good Sid.

 

question??

I didn't think about this when starting initially (*** U ME) that the flange for the turbo and the NA headers are the same??

If not I'll have to pick up another turbo crossover and chop the flanges off

 

Sorry Sid, I never checked. Hell, cut all the flanges off and just v-band it.

 

Whats the benefit to a twin scroll design?

Are there 2 separate impellers with 2 separate housings, though sharing a common shaft? Do you end up with a smaller diameter impeller and thus less inertia and faster spool?

 

I think the the wastegate off one of the tubes will work fine. had to on a few, but MANY aftermarket manifolds that work well, have this design built in.

I vote separate all the way.

individual pulses. a more constant pulse.

kinda 3 phase electricity vs single. Smoother power

 

cuz it goes to 11.

 

From what I understand it uses the individual exhaust pulses to spool faster and if you look at the turbine housing it has 2 smaller openings vs one large one and they both hit the turbine wheel in separate areas giving a broader pressure against the wheel.

The Idea IMO is to be able to utilize a larger hotside but still retain faster spoolup.

Evo guys are big on it

 

why for that funny bend near the turbo ??Steering ? I'm on the other side .My calculations of pipe cross sections came up with one was to half the standard XO pipe to set up for the same area it was equal to 2 pipes that were i think 1.2 or 1.4" Dia any how I found that twin 1.5" pipe would still flow better than the single .
so I think the twin 2" you have is too big to get something responsive .
as for waste gate it's seems school out for summer on that one we still are not sure about the amount of flow need ed in the hotside for hardcore E85 (high compr)
after the last findings of there being less in the exhaust than a similar petrol engine i would tend to go smaller .
mine are 2" for the first bend than 1.6 for the second 2 bends but I'm not realy happy with them as they have crappy steps in the pipe i would like to do some nicer ones later with sand bent 40mm tube and no joins

Despite the Opinoin I do still love your work Sid and hope it works great
are you going to wrap them up ?

 

nice work sid cant wait to see the results

 

Sid,
As always, you are up to something...Evo's you say? Is this what the desig is roughly based on?

 

Yes steering, quite the PIA really

Yea I was concerned with the size of the pipes. I realize I don't need this big but, I had a set of headers that were made for a one off project I did. Also I figured that if it did give a better response than the current setup that it would be fine and I can always make some smaller units (much easier for bends).

So it is a test of sorts.

The plan is to finish these and make a DP. then install them on the 86 see what a direct difference it is... then put the turbo ported head back on this engine and at that point I will dyno it again.

If all works out I should be able to have both cars running mid winter. If not the other car will be twin charged anyway so spoolup will be of little consequence.

 

Patrick it is actually from larger diesel engines. They don't rpm very high so they needed to make the most out of each cylinder pulse. The Evo's and Subies have just taken hold of it in the last few years. There may have been others in the interim but the diesels were the first.

Thanks again guys first go around things aren't as pretty but good for testing.

 

Toyota also thought it was a reasonable Idea badging it "twin entry turbo" in the late 80's and have a family of turbos with twin integral wast gates named CT i think from Hitachi

 

Are you trying to decide whether you like twin scroll design vs. twin turbo? Or just want a design from both sides of the spectrum? Very interesting project!