My compound turbo set-up

[jrohner]

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.

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.

 

[tenn-gsx]

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.

 

[WIDSM]

And I finally gave myself the comfy leather seats that I missed having. Can anyone guess which car they came from?

They look like Celica seats. Maybe..

 

[mach4g63t]

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?

 

[grantman10]

They look like Celica seats. Maybe..

+1 They look just like the seats out of my buddies 2001 Celica GTS...

 

[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

 

[tenn-gsx]

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.

 

[99gst_racer]

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?

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?

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.

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.

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.

I cant find pictures of that but a quick search found this new 1.9tdi with staged chargers
Fiat Powertrain: 1.9 JTD Twin Stage Turbo with 100 hp/liter

That almost looks like the exhaust routing of a compound set-up, and similar compressor routing to that of a sequential set-up. Looks interesting.

 

[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.

 

[99gst_racer]

Yup, they're Celica leather seats from an '05 model. They're awesome thus far.

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.

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.

 

[duwackerTSi69]

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.... Just got them installed about 2 weeks ago, but in cloth?? Great minds think alike,...Haha

 

[jrohner]

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.

 

[delta448]

Exhaust route = 2G manifold -> 16G turbine inlet -> 16G turbine and wastegate outlets -> 60-1 turbine inlet -> 60-1 turbine and wastegate outlets -> normal exhaust piping -> atmosphere

Intake route = air filter -> 60-1 inlet -> 60-1 output -> 16G inlet -> 16G outlet -> intake

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.

 

[duwackerTSi69]

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,.. Its a learnig process, so take it easy

 

[jrohner]

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.

 

[1sttimedsmr]

Holly guacamole! This is the sickest set up I have ever seen. Don't get it wrong, but I am thinking on copying your set up for my ride. Hope you don't mind.

 

[brian9397gsx]

i cant wait to see how this turns out. im a big fan of twin charging you see it alot in the diesel world but not so much in the gas engines which is kind of a bummer. also with what you have all ready said you will be using for fueling and your knowledge ive gathered so far i really think you know what your doing and have a good grasp on what needs to be done. cant wait for more updates

 

[dsm-onster]

It's a fVcking joke that there's even anyone even debating that this won't work. It's not like the slow bumbly exhaust of our diesel counter parts arn't doing this already. Any one who wants to debate combustion chamber pressure and knock, should relax and enjoy the fumes.

 

[dsmfa9nutter]

Insane to say the least. 1600cc's right?

 

[viperlp01]

Ya please stop saying this wont work... The hardest part is going to be tuning but isnt that always the hardest part when trying to reach 600 hp... Im waiting to see pics paul. Did you make it to the company meet?

 

[RipperXX]

I think it is amazing that no one has tried this yet

 

[v8s_are_slow]

Probably because not everyone has heard of it. Lol. I for one haven't heard of the compound setup until, well, this thread. Learn something new everyday I guess. Really hope it works out well for ya. I for one though want bolt-on parts cause the fab stuff can be a pain in the ass or trying to replace something that broke. Want everything as easy as I can get these days. Don't wanna spend 10 years trying to figure out the best tune for my ride. But hoping it won't be difficult for ya and hoping to see good numbers. I'd like to see vids of this thing running though.

I think it's funny though that you're talking about noise levels yet you're running the side exit exhaust. Lol. That's what I wanna do though but with a muffler on it. You doing anything for the rear bumper? Looking into the best ideas of not having the naked gaping hole in the back for where the exhaust is suppose to be. Anyway, good luck on this thing.

 

[rush2252]

that isnt for the exhaust its for the external o2 dump

 

[v8s_are_slow]

Oh yeah, that's right. It's late. Forgot about the dp pics he posted up. Was just looking at the bumper and forgot all about it. Nevermind!!!

 

[RipperXX]

If people would go to a book store and look, theres actually a few good books on turbo charging...I did this a few months back, and I learned a few new things. For one, how to actually read a compressor map .








Again OP, I am kinda surprised no one has tried this yet, I am very interested in how well it works out for ya. If you have the funds it would be very interesting to log air temps at a few different points. Like ambient air temp at the intake, one in the charge pipe going from the big turbos compressor to the small ones, and one on the outlet of the small turbo, and then the TB. Also I think the idea of a water to air IC system might be something to consider if you have the room for it and $, time etc. At any rate good luck with this, keep us updated!