gwhammy

This idea on twin wastegating has been rolling around in my head. What if you ran all of the air out of the little turbo into just one side of the big turbo. Then using an external wastegate, it would be ran into the other side of the big turbo. I know it would require some extra fabrication work but not a whole lot. This ought to give some extra kick to fire the big turbo off as you would have half the exhaust housing size but still have relief when you hammer it hard and the wastegate kicks open.

I know when I was setting up my twin setup I ran without the big turbo hooked up and the wastegate would keep the motor at whatever boost pressures I wanted. Does any of this make any sense or am I just having a pipe dream I've talked to some tractor pullers and they used to weld one side of the turbo scroll shut if they couldn't spool it. Kinda crude but effective back when all they had was stock turbos to work with.
How about some input on this or just tell me I'm beating two

Artsi_L

I've thought that very same idea myself as well. Originally I got the idea from ATS's web page on Aurora turbo's (see link below). Corky Bell's book on turbocharging has this flapper valve turbine housing idea presented. Who knows.. maybe that's where ATS got the idea from.

I think it would definately be worth trying out. To this date I have not been able to find any drawbacks on that wastegate venting arrangement.

I'm sure it'll work better than present way of doing the hot side piping on twins.

http://www.atsdiesel.com/ATSWebsite/...rboSystems.asp

RowJ

Interesting concept. Is your lag that bad... or is this a fun idea for a winter project and a 'pushing the envelope' kind of thing??
Is there room for everything?? Sounds tight.

Theory is interesting but my mind wants to say that in practice, it's not really valid. Can't tell you exactly why?? Have the Aurora's been proven to work well. Seems like little has been said, after the big introduction?

RJ

gwhammy

No, the lag is no problem with the setup I have. I'm just never satisfied going down the same road all the time. If I don't sell the k-31 I have I'm thinking about putting it on one of my trucks with one side blocked off and leaving the side with the wastegate open. That would make it a 10.3 mm exhaust housing with a 66 mm wheel. It will probably make to much exhaust back pressure but all it will cost is a little time. If it did work it would be neat to have a fast spooling 66 mm turbo with a big wastegate on it.

I'm pretty sure there is room for it all, both pipes will narrow at the big turbos flange. The main pipe could come out 2 in enstead of 3 and then have the side trimmed off of it heading towards the bottom flange. A 55 mm wastegate only 4mm short of 2 in too so they would cut together with a divider plate welded between them.

The 01 just got a good transmission in it and has a set of mach 6's coming for it. It's gona get either a drag comp,edge hot juice or a p-pump setup on it by Jan. Just a guess but I'm thinking the hy is not going to like the extra fuel. I don't think it likes the ez with 125 horse injectors to well!

I am kinda leaning towards the hy with a 3b or s400 under it and a 50mm wastegate to get around the hy's shortcomings. The reason for this thinking is I'm afraid the hy will start laying down before the bigger turbo comes on.

TheBigNasty

I agree...i want to see those drive pressures.

JDGnut

Hmm.. .. I've had all the parts to build that setup for about 9month.. just never built it... (Also would work on a big single..) but heard that they had tried this years ago.. and had turbo problems.. Might not be an issue with todays turbo's... Maybe one day I'll get started on it...

RowJ

You mention a 55mm or a 50 mm. If I follow what your saying, you might double check size you want on the Ext Wastegate? I ran a 38mm for 2 yrs and it handled 550 hp on an S300 turbo (KSB-1). Couldn't overdrive the 38mm at 40 psi. Just a thought.

I was accurately (I think) warned by 'Banshee' that going any bigger would cause flutter in the gate opening & closing. Never tried bigger so don't really know?

RJ

gwhammy

The one I have extra is a 50mm. I built a couple of 1.75 throttle blade type wastegates for a friend of mine on a twin turbo big block chevy a couple of years ago. With the hood off you could watch the wastegates work and they fluttered like crazy so I know what you are talking about. My 97 has a 38 mm external gate on a hx35 and you can hold it at whatever boost you want.

My only thinking on the bigger wastegate is to try to equilize the pressure on the choke using one side of the big turbo. It won't hurt anything at lower boost but if you are using say a 32 cm housing on the big turbo that would make you shoving alot threw 16 cm on one side.
I have all most all of the things needed to put this setup together I would just like to figure out which way to go so I don't have to do it two or three times like I usually do.

RonA

You ought to try using the k31 on the bottom in your '02. There was a 3rd gen recently that put in S300/k31 twins. He did 609hp on the superflow and couldn't get it over 1250 up in the hills. Turned into a street sweeper in 4th gear with a pedal mash. Put those new Mach 6's to use.

Ron

gwhammy

The k-31 I have has a 66mm cold wheel on it. I didn't figure it would be big enough for a twin setup. Didn't you tell me one time the one you were using had a 71 mm wheel on it? It also has a 20.6 exhaust housing on it which is pretty tight but it also has a wastegate which might offset the small housing. It would probably spool like crazy but how much horsepower do you think it would support? I know the top turbo will be either a hy or hx 35 with stock housings on them.
This is going on a 01 I have, my wife won't let me put twins on her 02. She likes the loud straight pipe and doesn't like how quite the 97 got with twins. Go figure!
I'm waiting with great anticipation for the 6's, but something has the be done with the poor stock hy before I take the 125 horse injectors out.

RonA

Mine measures around 70mm or so and has a 24cm housing. I did not know they made different sizes. 66 would be a bit small I think.

gwhammy

I asked this before but not sure I got an answer, I kinda got a bad case of CRS. Do you think I could get a bigger cold wheel and housing to put on this turbo? I tried htt turbo some on this idea but they couldn't come up with any numbers. Ron, do you know what kind of exhaust temps that truck had at 600 horse. You are the only guy I have seen that has said anything about the k series turbos.

signature600

Sure you could...Try City Diesel, Scheid, Haisley, Columbus Diesel Supply, Etc!! Someone should be able to get you the parts!!


We're changing the wheels in an S400 from 66mm to 74mm

Chris

RonA

You are going to start seeing more of them. NW Customs has been doing them for a while. Industrial injection is using it in their new smaller twins. I heard that the 609 run was down in the 1100egt range. They spool very fast, and the dyno runs are quick. Out on the road he said he could not get it over 1250 empty, even in the hills.

signature600

All this talk about twins makes me want to start BOMBing the 98 even worse....this really sucks

Chris