No twin turbo even thought of.

Initially I decided to change the hotside to a T3 to cut down on spool time. I would have had to either modify my current unit again or get another. Then I found this small T4 but it's entrance is in different location than my current unit (current is "on center").

No matter what, I needed to modify so I thought why not try something else...Twin scroll ..it may give the best of both worlds w/o stepping up to a DBB unit. Plus Holset doesn't make a DBB that I know of and the Garretts I have used don't seem to hold up to really high boost . I don't feel like spending the $$ for a DBB and be dissapointed when it either, doesn't do what I want ,or breaks.

The "twin charge" comment is related to another project altogether using a supercharger and turbo together.

 

i want to twin charge one of these :/

 

make sure to use 2 wastegates and make sure to not join the pipes anywhere, other wise you have defeated the purpose of a twin scroll system. Also that last bend is pretty sharp but if should work fine.

 

My bad, took twin charged to mean twin turboCharged.

 

Nice to see someone doing this,I am using a twin scroll gt35 on my 968turbo project.You can get away with one wastegate I think but both pipes have to go to it,bit of a challenge for you.Not sure if that hotside is big enough, how do you calculate that is is the same as t3 .82?

 

OMG how did I miss that project..WOW..

I really love the exhaust. I see the WG port is close to the flange. If I end up running off of both pipes I will most likely put it up there. IN the meantime I am going to tap just one pipe down low where the stock WG location is. I have seen twin scroll manifolds that have been configured both ways. Not sure how they compare.

Only time will tell. If I were running low boost I bet I would need to have both tubes tapped but I'm hoping that it will not creep with just one.

I am pretty sure that the T4 .48 is not too small. I currently use a .58 and it is way too big for street use.

I measured the entrance of both the .82 t3 and the .48 t4 to come to that conclusion for sizing.

Honestly I am hoping that it is smaller that the .82 t3 for spoolup puposes as this car will ultimately only be a 25 psi unit.

 

Well it is not ideal to only use half the cylinders to control the boost.

You will know pretty soon if the hotside is too small, it is a bit difficult to compare single and twin scroll sizes, not a lot of info(or options) out there, but general practice is that twin scroll should have a bigger a/r.I am using a 1.06 t3(the one in my avatar is an .82 t3), but time will tell if it is big enough, it should be comparable to .82t3 open.

Yea my project is a bit crazy...

 

I sujjest the WG hooked up to the hotside port closest to the turbo bearing housing these pulses will be see more turbine blade than the the ones in the other port .
so it would have more influence on turbine speeed than the other port

 

Excellent work Sid!
Looking forward to the results. Twin scroll is really the way to go. I'm very keen on something similar myself but I just hate working around the steering..

 

Adam,

That's what I was thinking. I have also been thinking about using 2 smaller pipes that stay separate all the way to the WG flange. IE: having a piece of flat stock separating the 2 at the end with the pipes cut in 1/2 mated together

Thanks Duke, yea theh steering is a PIA
I will clean that up at some point but even though it has a sharp bend there the pipe size should allow for enough flow

The darn flange was sitting in my mailbox on saturday. Probably a good thing b/c I have a little more time to think on it

 

Just a thought. Would it not be possible to run a custom twin scroll housing that had one of those attached or internal wastegates, thereby negating all these other issues? I know that they're not meant to be as good but I'm not sure why? Internal w/g that is.
http://www.timsturbos.com/HX40_DSM.html

 

That isn't a twin scroll just an internal WG

I haven't used an internal so I don't know how well they work.

Also the place where I pick my junk doesn't have any fancy stuff laying around

 

Yeah but that can be ordered in Twin Scroll housing and have internal w/g Sid. I just was really thinking about the concept of not having to find a place for a w/g in a twin crossover situ. More just an idea. Seems like ideally you would want 2 w/g, but then could they get out of sync? Therefore it just occurred to me while I was surfing around looking for something else that I saw that particular turbo.
You gotta go to a better standard of junkyard Sid.

 

the idea has merit as Integral gates are OK but they are only OK when the A/R is big enough.
PAT have have you seen these housings in GARRETT config?? as i believe them to be a Hitachi thing and not sure if compatible

 

The two smaller pipes merging is how mine was done, it is very important to keep the pulses separate, all the way to the valve.Two wastegates is ideal but that takes up a lot of room.

I tell you it is more of a problem with the steering if you are rhd!