You have anymore pics or updates today. I just think that people like you who think out of the box and have the fabrication skills to back it up are awsome. Keep up the good work and keep us updated.
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This setup on a 4g63 is gonna be sick man! I'm curious as to what/ how you're going to control boost, one MBC for each turbo fed off one pressure source maybe?
Very nice! I am glad that you routed the wastegate from the first turbo into the inlet of the second. Before I saw that pic I was worried that you were just going to dump it to the exhaust.
I just hope that the wastegates flow good enough. At least half of the entire exhaust flow is going to go through that first wastegate once you are into boost.
Seems like this setup should be able to make some rediculously high pressure ratios.
Boost control will be by the wastegate springs only. No boost controller - at least not for a while.
I have a 'T' on the 60-1's compressor cover for both wastegates. And of course, the 16g's wastegate uses the top port to reference the higher atmospheric pressure due to the 16g's new inlet pressure.
And yes, I ported/blended the hell out of the compressor outlet of the 16g before welding to it.
Quote:
Originally Posted by bpestilence
Very nice! I am glad that you routed the wastegate from the first turbo into the inlet of the second. Before I saw that pic I was worried that you were just going to dump it to the exhaust.
I just hope that the wastegates flow good enough. At least half of the entire exhaust flow is going to go through that first wastegate once you are into boost.
Seems like this setup should be able to make some rediculously high pressure ratios.
Yeah, both wastegates are going to be working O/T often. That's one big reason what I recirculated the 16G's gate. The OE cast manifold and 7cm turbine housing will become a restriction at some point, but the wastegate will be diverting a large amount of that exhaust energy around the restriction and directly into the path of the T4 turbo. Perfect.
I re-routed the 60-1's wastegate simply because I'm getting old and am willing to try having a quietier WOT. For once, I'd like to hear that turbo (i mean, those turbos) spool.
The 44mm gates should be fine. I'd hate to think I need larger.
Last fall, I figured out what it's flow rate would reach if I maxed out each compressor. IIRC, it was somewhere in the 120's PSI. Assuming of course all other restrictions aside. I won't even be tickling the thing to get what I want out of it.
____________________________
-Paul Volk-
'99 GSX
'91 TSI
No new turbo progress pics. We're having our company car show this weekend, so that kills my free time to work on the car. So close to having it done for the show...
Just for shits and gigs, here's some progress on the rest of the car. Excuse the blurry pictures of the dusty parts. Everything needs a bath at this point anyway. Including the camera.
New front bumper. Yay! No more blitz!
And I finally gave myself the comfy leather seats that I missed having. Can anyone guess which car they came from?
____________________________
-Paul Volk-
'99 GSX
'91 TSI
Yeah, both wastegates are going to be working O/T often. That's one big reason what I recirculated the 16G's gate. The OE cast manifold and 7cm turbine housing will become a restriction at some point, but the wastegate will be diverting a large amount of that exhaust energy around the restriction and directly into the path of the T4 turbo. Perfect.
It wouldn't work well to dump the 16G's wastegate anyways would it? You'd be losing a lot of exhaust energy that is very much needed for spinning the larger turbo.
Won't the compressor on the smaller turbo be a restriction to the 2nd turbo? Won't the compressor on the smaller turbo be a restriction to the 2nd turbo? I suppose the bigger one will pretty much be sucking air through the 1st by some point but wouldn't it still be somewhat restrictive?
I'm also wondering, when you do turn the boost up, if the wastegate should maybe be set to a lower boost pressure (like 20psi max) on the smaller turbo since that would minimize the exhaust back pressure / restriction. If nothing else, the smaller turbo could have a really soft wastegate spring (and a boost controller to raise the boost substantially) so it can blow open with exhaust pressure.
I'm eager to hear the results for the HP, spool, and of course, reliability. Great work so far
The whole setup looks awesome, can't wait to see the finished product to see what kind of numbers it makes.
What kind of seats are those and where can I get some?
Tom
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-Tom
-Red 95 Talon TSi AWD w/ Built 7-bolt
Like I said before, the exhaust manifold and plumbing is going to be the most important part, because it's actually going to see the total pressure differential across the walls of the piping and restriction of two turbines. As long as everything holds the heat and pressure you should be set, especially with the coatings to help hold thermal energy. Dialing in the cam timing will be interesting too I imagine.
Quote:
Originally Posted by knochgoon24
So, if they get SD to work on the Evo 8 ECU...
It already does, depending on which ROM image you use and how willing you are to deal with annoying CELs. In order for us DSMers to take full advantage, they just need to get it working on a ROM image that doesn't throw a code for the cam/crank sensors, for example: the European or Australian domestic market ROMs.
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Zack H.
R.I.P. '97 TSi AWD
Last edited by Defiant; 05-27-2009 at 09:16 PM.
Reason: Let the Moderators moderate.
I think this setup fails in design. the first turbo is simply in the way of making power. The compressor side is fine. Its the exhaust side that will not work like you hope. The 16g will overspin and die very quickly, the second turbo will not recieve enough exhaust energy through that small wastegate Compound turbo setups work well on diesels where they should stay. Diesels tolerate very high boost pressures because the engine itself runs off autoignition point of fuel/air charge.
The AMS design staged twin turbo was brilliant by design compared to this setup. They only had a few days to get car ready for event . they feared they wouldnt have enough time to work out bugs so they had to abandon the project.
Won't the compressor on the smaller turbo be a restriction to the 2nd turbo? I suppose the bigger one will pretty much be sucking air through the 1st by some point but wouldn't it still be somewhat restrictive?
:
The 16g compressor is 2nd in line on the intake side which means it will pull the air through the larger compressor. By the time the larger compressor is doing any work the 16g will just be compressing the air even more so there won't be any restriction there either.
Yeah, I see that now. It still seems like it would be a restriction though to me. That tiny compressor can only flow so much no matter how you're cramming air into it right? I think the turbo's would have to be designed specific for a setup like this to make the most of it -- compressor and turbine sizes. It definitely seems like there would be some compromises having a setup like this, but I'm not saying they aren't worth it -- fast spool and low end torque, yet good top end hp too. If you set up your engine (and everything else) for very high boost, it would probably work quite well. It's definitely added complexity and weight, and it seems like a lot to fit in a small space if used on a street car. On a drag car, you can make things fit easier than a street car. Are you going to fit a radiator in there? If so, I take it you'll have pusher fans on the front of the radiator.
Quote:
Originally Posted by 94awdcoupe
The 16g will overspin and die very quickly, the second turbo will not recieve enough exhaust energy through that small wastegate
The wastegate will be bypassing a lot of that small turbine of the 16G though. He may need a larger wastegate on the 16G since I assume the bigger turbo will be doing most of the work in the higher engine rpms. All the exhaust will be going to the 2nd turbo, not just the exhaust wastegated off the 16G.
The 16g doesn't care how much pressure there is entering it. All it cares about is volume. So if you have two times as much air coming out of the larger air than normal it wont matter as long as its compressed enough to stay within the capabilities of the 16g. The biggest issue that i have heard of being potential blowout of the 16g compressor cover. Not because of volume but because of feeding already compressed air into the inlet and compressing it even further.
How do you plan on combating all the extra heat radiation? Your basically throwing another DP up there with that exhaust re-routing for the second turbo. Not to mention you have another bare turbine shitting heat all over the place as well.
I think this will work but keeping functional for the street will be the largest PITA. And as stated before, I think the 16g can take the abuse of being force fed... but for how long?
Also, after looking at one of your pictures... it looks great, but how accurate will one WBo2 be so far downstream of the exhaust? Yes, it's right after the 2nd turbo... but won't all that extra exhaust plumbing give potentially richer than usual gas time to burn up before being read thus causing excessively rich conditions from the combustion cycle? I don't know if that makes since but it's just something I felt I should bring up. Also, where will you put the narrowband? Would it help to have a metering device between turbines at all?
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92 TSi- 6/4 - Auto to Manual
Man. that is just one awesome setup, one thing i'm trying to figure out is what turbo map you would base your power on roughly? I'm actually wondering if you compounded two 14b's into one would you be able to make say 400 instead of about the 300 max of one 14b, or are you limited to the flow of one of either of the turbos?. I definitely think some meth injection, E85 and maybe even a water.air IC would keep things coole enough to DD the car. I may have to drive to where you're at just to see it first hand and beg for a ride
Im pretty sure 2 turbos of the same size would just make the second turbo usless since it would be pulling the compressed air and the first turbo couldnt keep up with the demand of the first one. Remember this is basically multiplying the ability of the smaller turbo to create boost. So you need the bigger turbo with the ability to flow a larger volume to feed the smaller turbo and make it work.
I think this setup fails in design. the first turbo is simply in the way of making power.
Care to cite anything to help form this opinion to fact?
Quote:
Originally Posted by 94awdcoupe
The 16g will overspin and die very quickly,
What makes you think the 16g will "overspin"? You do know that exhaust energy controls the speed of the compressor wheel, not the inlet pressure of the compressor, right?
Quote:
Originally Posted by 94awdcoupe
the second turbo will not recieve enough exhaust energy through that small wastegate
It won't have to. It will also receive the exhaust exiting the 16G's turbine housing.
Quote:
Originally Posted by 94awdcoupe
Compound turbo setups work well on deisels where they should stay.
Funny you say that - I was originally turned onto this idea by a guy that did it on his 2.3L pump gas Ford Ranger. He hits 30 psi by 3000 RPM's and was trying to source out a clutch that doesn't die immediately.
Quote:
Originally Posted by 94awdcoupe
The AMS design staged twin turbo was brilliant by design compared to this setup.
Yes, it was an awesome looking set-up. But it was a sequential set-up, not a compound set-up.
99gst racer, dont mind the peiople who want to say it wont work. It is a proven system on plenty of vehicles and it CAN work. Lets just hope that your design is sufficient to prove it to the nay sayers.
Yup, they're Celica leather seats from an '05 model. They're awesome thus far.
Quote:
Originally Posted by turboglenn
Man. that is just one awesome setup, one thing i'm trying to figure out is what turbo map you would base your power on roughly? I'm actually wondering if you compounded two 14b's into one would you be able to make say 400 instead of about the 300 max of one 14b, or are you limited to the flow of one of either of the turbos?. I definitely think some meth injection, E85 and maybe even a water.air IC would keep things coole enough to DD the car. I may have to drive to where you're at just to see it first hand and beg for a ride
I plan to use both compressor maps to determine how efficient they are operating, but I don't know how you would calculate HP with them. I planned to estimate power with the good ole butt dyno and a good datalog. And eventually dyno it sometime this summer.
I figure more really dense air and more fuel - Should have a very large flow and overall power output. At least, that's what I'm hoping for.
A direct port meth injection kit is coming up on the list. If I need more, I do like the idea of a nice A2W intercooler set-up. I can't think of a possible solution that I like any better. Ohh, and I'll be at the Shootout this year if you want to check it out.
Quote:
Originally Posted by tenn-gsx
99gst racer, dont mind the peiople who want to say it wont work. It is a proven system on plenty of vehicles and it CAN work. Lets just hope that your design is sufficient to prove it to the nay sayers.
He has a right to his opinion. I just saying - if you want to disprove something, then at least back it up with an intelligent rebutal.
I'm not saying this is the cat's ass - yet. I'm just extremely optimistic right now and I want to hear thought behind reasoning.
However it turns out, I'll share. I sure hope the design performs well. It's about the only way it could fit in the 2G bay. lol
____________________________
-Paul Volk-
'99 GSX
'91 TSI
Good job on the fabbing skills, but I gots a question for ya, or anyone that want to take a crack at it??
So basically all in all your doing a sequential twin turbo set up, right? I read about 75% of the thread and was wondering, dont you need alot of solonoids and vacume line junk to controle tho's turbos of yours?? What I mean is, once the smaller turbo starts to spool first, while its at max boost, it pre-spools the 2nd turbo so it can take over from there. Right? What stops the smaller turbo from recieving all the exhaust gas and re-directs it to the bigger turbo that way it can produce max power with efficiency?? Or what is going to happen at that point on your set up??
I used to own a 3g Rx7 with a 13b-rew rotary engine, and they are equiped with "true sequential twin turbos", and I am not kidding, those things had about 20ft of vac line with lots of solonoids to controle them. I could have full boost(9-10psi) at about 1,300rpm, all the way to 4,500-4,700rpm, and then theres a "change over" to redirect the exhaust gas to the bigger turbo and continue with full boost(about 14-17psi) to redline(around 9k rpm).. At the "change over", it would be such a big power difference that it would kick my ass end out and be hard to controle? It was a huge PITA, because I would have to let off the throttle! And then all all the vac lines would get blown off, then you had to dig in a cramped engine bay to find the one that blew off?? Took hours sometimes??
Anyways, why wouldnt some one try them turbo's out? You could run them in Paralell mode(non-seq), and esentially have the same thing. Here is what they look like? They might be a good setup for a 4g63T? They are like T25's to a 1.3 rotary? With more of a punch..
99gst_racer, I have the same seats in my 2g talon..lol.. Just got them installed about 2 weeks ago, but in cloth?? Great minds think alike,lol...Haha
So basically all in all your doing a sequential twin turbo set up, right?
A compound turbo setup is not the same as sequential.
Compound doesn't 'switch' between turbos, the exhaust and air go through both of them all the time. There are no valves or controls other than the wastegate on each turbo.
Paul, I don't know how you'll determine the efficiency islands on the compressor maps. With the intake air being compressed twice, the efficiency of the larger turbo is going to be changed as if it were feeding a larger engine with a changing displacement (changing with the amount of boost the 16G is applying). The 16G is going to be pulling vacuum through the 60-1's output even when the 60-1 starts making boost, up until the 60-1 overruns the flow through the little compressor. That will make the pressure ratio across the bigger compressor a lot lower over all points and act like higher atmospheric pressure at the larger compressor's inlet.
A compound turbo setup is not the same as sequential.
Compound doesn't 'switch' between turbos, the exhaust and air go through both of them all the time. There are no valves or controls other than the wastegate on each turbo.
I understand what your saying about a compound turbo setup, but wouldnt it be even more efficient if the exhaust gas got re-directed to the bigger turbo when its at the upper rpm's?? Sounds better in my mind, but I am no turbo expert by far? I know my opinion is not going to make the OP change his mind on his setup, but this is for, I guess you could say "arguements sake" and efficiency? From what I have read and heard, turbo's like HOT exhaust gas's, hotter the gas, the more energy it has stored. I would think that alot of that heat is disapated through all the piping and by the time it gets to the 60-1 turbine, is significantly cooler then when it was just pushed out of the head?? Thus not operating at a great enough performance level?? And not to mention the compressor side of the turbo. say that if you hav 2 air compressors hooked to the same air line, and 1 a/c is bigger then the other, the bigger one will try to over power the small one and basicaly make the smaller one pointless to use?? Right?? Just asking here, so dont flame me or anything,lol.. Its a learnig process, so take it easy
Last edited by duwackerTSi69; 05-24-2009 at 10:14 AM.
Reason: mis spelled words
Much of the exhaust gasses will bypass the smaller turbo by going out the wastegate. It will probably take some trial and error to get the boost set right on each turbo, but I think if they are set independently of one another and the right settings are found good results could be had. I think a setup like this will allow for and possibly require higher boost than what would otherwise be ran.
On dieselpowersource.com, which I think is linked to previously in this thread, they had less exhaust backpressure at high boost levels than with a single turbo. With a small turbo being maxed out you may have twice as much pressure in the exhaust as the intake, but they were not far from equal at 60psi with.
. Seriously. 
What makes you think the 16g will "overspin"? You do know that exhaust energy controls the speed of the compressor wheel, not the inlet pressure of the compressor, right?
Or what is going to happen at that point on your set up??
