I was looking around for different turbo Ideas and stumbles across a compound turbo setup (not the same thing as a twin turbo). This looks like an amazing setup, all the boost of a large turbo and the throttle response of a small turbo!

This is how it works. Basically a smaller less powerful turbo, (faster spooling turbo) is used to spool up a larger more powerful turbo (slower spooling). Being that pressure ratios multiple, this type of set-up can yield a large amount of dense air very quickly.
Translation = lots of boost and very quick spool! Another huge advantage to this type of set-up is that it's capable of running more boost than any single turbo. This is how tractor pulling guys achieve 200 psi boost.

300ZX streetfighter video
YouTube - Marc's 2JZ Turbo Compound Setup

video of the 300ZX 700hp (aka streetfigher) beat a 1002hp C6 corvette!
Roll Racing-23 1000whp C6, Compound turbo 700+ whp - Car Videos on StreetFire

Here is an article from borg warner on compound turbos
Regulated Two-Stage Turbocharging for gasoline Engines .

What do you guys think? If a vendor made a compound turbo kit for the LNF Cobalt would you purchase it?

 

there is a guy doing one/shop on a sky, I have been following it on facebook, pretty neat stuff
the aim is 600whp
http://www.facebook.com/#!/profile.p...00001304390942

 

i say no because it would be a BITCH... not imposible but a bitch...

 

No. The turbo going on my car will be able to make 600hp by itself. The compound is nice because of the power curve you will have but it's not something I will need.

 

Doubt there's enough space in the cobalt to fit two turbo's, it'll definitely be a tight fit on that sky.

 

Which is why they were doing a remote-compound-setup.

 

me and a friend were looking into doing a set up like this on my car. there is a lot more room in the engine bay than you think in these cars you just have to move a few things around a little . Our idea was to actually use the factory turbo and one equivalent to a gt35 or a little larger to be able to run say 15-16 psi up top much more efficiently. think of all the heat you will be getting rid of up top and you would still have the same throttle response down low..... How many people would be interested in a kit like this if it could be done for the same price as ZZP's big turbo kit?

 

It would be cool to have but not for the price you would have to pay..

If it's cheap I'll buy it

 

I'm the sky with LNF building a compound turbo: https://www.cobaltss.net/forums/adva...-build-223923/

you can also follow it on facebook, which is under my signature.

If you are ready to drop at least $5k on engine internals and labor........then you can start thinking about compound kit which will cost a lot of money as well. The compound kit will be useless, if your block will not be able to handle it. Same thing with your tranny/clutch/etc....

I am very fortunate that many shops sponsored me for my build, or else I will not do it.

It is just too financially exhausting, IMO.

 

I wonder if just adding a Larger Turbo with the one we already have would work? Our turbo has almost zero lag as it is. We just need a Larger one along side it to really kick some ass!

 

that's what I thought first, actually. It is a lot easier, and you'll have more space!

Plus the tubing running underneath your car (big turbo's compressor outlet's tube going back to the small turbo
s compressor inlet), will act as an intercooler as well.....which is a plus! Interstage-intercooling right there!

But you have to consider the lost of thermal velocity/heat loss from the small turbo's exhaust/dp...going to the big turbo (turbine inlet). That's a long tube of travel.
You also have to add pump for turbo oil of the big turbo.
Then when it rains or deep puddle...you have to worry about the big turbo's air filter sucking water But if you drive your car only summer...you don't have to worry about it. My car is a daily driver.....so I have to worry about a lot of things
So those are a couple of things to consider.



I changed plans, and decided to have both turbos inside the engine bay.

So good luck bro. It will be very interesting build!

Keep me updated!

 

Try it! Before, I wanted to use my k04 turbo with my gt3582r turbo compound set-up.

but I changed my mind. I would like more power than gt3582r so I ended up upgrading both turbos

Always consider matching the turbos. There's no science behind it, currently its a black art.

That guy on the video you posted is my friend Marc. We talked last year for hours about his compound turbo....and he's the one who pushed me to do compound set-up as well.

You can't just stick two different turbos and expect good results.

He told me that after their first succesful attempt of compound turbo.....they immediately changed turbos hoping to get more whp. Unfortunately, after putting in two larger turbos for their set-up.......instead of getting more whp....they lost both whp and tq. The compound set-up became so sluggish.

so matching turbos is a sensitive thing

 

Thanks for the info Lipstick. Your build is going to be ridiculous. I hope you make EVOs cry!

Yeah 5k is a lot of money not to mention the extra for the compound turbo it self. I know ZZP makes an upgraded engine for the LNF (about 5k). I bet that could handle a compound turbo. Now if ZZP can just build the compound turbo for the LNF and mass-produce it, hopefully it would bring the cost down a little.

 

thank you

is the ZZP upgraded engine already have aftermarket sleeves?

I highly recommend having sleeves on your block to make it more stout.

Like what I already mentioned, you also have to consider your clutch/tranny/axles.

plus selling a compound turbo kit...is tough. I'm not sure if ZZP will be willing to spend time on RnD on it.

That guy Marc is from boost logic. I know that Boost Logic tried selling these kit about 2 years ago to supra owners. I know there's a lot of supra guys VERY interested. But I'm not sure if they stopped selling it or its still available or sumthing. I dont know why. Lots of factors involved........
I only know one supra who has it. Other people backed out...

compound turbo is not for everybody.......

 

ZZP's uses gen 2 blocks. So there rated at 700 or so as is. They have made 62x with Ryans lsj which has a gen2 block. If I was going to be drifting or autocrossing a compound setup would be nice, but for drag racing it's not needed.

 

how about trying to spool the big turbo off the line?

My friend Kevin Jewer, who actually is another guy with compound turbo set-up on his DSM is another guy who influenced me. He used to have 1.01 T4 GT4294, but used a nitrous, to spool it. He runs mid to high 9seconds on it. I believe its around 600whp

When he went compound turbo (t3 50 trim and 1.32 T6 s475 turbos) , he was able to go 8.80 sec @ 156mph.

Kevin did the compound turbo...to see if it really works. He did all the work himself, and he's happy he did it.

some of his videos: http://www.youtube.com/watch?v=vhiKLm9E6UA



But you are VERY right, most drag racers, dont need the wide power curve of compound turbo.....since you guys are always at the high rpms

this is why I mentioned, compounding is not for everyone!

 

Ehh here is Kurt Brown at the dsm shootout this past year. No problem coming off the like with the 2 step. The 2step helps ALOT lol

YouTube - Curt Brown 2010 Buschur Sport Compact Shootout

And here is my friends srt4, no nitrous. AGP Zeta 3.2

YouTube - ERABBIT23 9.87@149.53 Top View

 

hey man, I was trying to find that pic you posted of the v6 mani built for a compound by the company doing yours,where is it? this is Thomas Z btw.

 

I was wondering what our current stock blocks/pistons are rated for... I had hear some murmurs n the past from folks about when a car has its Horse power assigned to it once its been through its test phases, that there is a certain percentage above which, the block can go above without harming it... and I thought it was 100% ( Saftey standards and testing ) ... so for example, our cars come with 260, so we could theoretically do up to 420 on the original block and pistons, obviously not reccomended, but theoretically doable... most folks will only do 50%of that... I dont know if this is the case, but I've heard some stuff on this before.... any one hear anything like this?

 

The motor would last a good time at 400-430whp I would say. Thats prolly conservative.

 

are you talking about this?


It is not from my company.......it is a good manifold to follow!!!

 

ah yes that it,(my bad I though it was your shops work)regardless its just a awesome pic.

 

the stock LNF rods, start bending above 400whp on the sky/solstice side


I won't push it above 450whp even with a great tune..........or even extra protection such as water/meth.

 

From reading everything I am less sure of a compound turbo setup. I though a compound turbo was superior to any one single turbo, however if drag guys aren’t doing it, auto x guys aren’t doing it, 2012 Indy car isn’t doing it, 2013 F1 isn’t doing it, Rolex 24 isn’t doing it and manufactures aren’t doing it. There must be a reason they are not making a compound turbo system.

So, it’s all about power band right? I’m guessing a compound turbo is gives you a wider power band, however if you have one large turbo and never fall out of the power band then is it pointless to do a compound turbo?

Here is my theoretical scenario for everyone to discuss:
You have 2 identical cars.
Car 1 has one large turbo (600hp@7000rmp 600tq@4500rmp)
Car 2 has a compound turbo setup (600hp@7000rmp 600tq@4500rmp)

Who would win in a ¼ mile, 40-120, 60-100, 100-150, 0-100-0, autoX, oval?

 

compound turbo is not being used alot by Drag racers since, they dont need the power at lower rpms. Plus the complexity in tuning and fabricating of compound turbo is a pain in the buuutt. Financially it is very expensive too. So why would they go with compound? There's no reason. My friend Kevin, which I showed video....did a compound turbo on his DRAG CAR....because he wana see if compound works. And he was very happy with the results...and made his car faster....w/o the use of nitrous.

AutoX guys dont use compuond turbo due to many reasons. First, they dont want to go to a higher class. Second, the top end power is not necessary on their sport. They just need the low and mid range power. Third, I mentioned above (complexity reasons). Plus lots more.

other Race organizations, might not even let cars with a compound set-up join. I'm not really sure about their rules and regulations.

If you have a large turbo, it will fall out of power band....since its just peak power.....especially if you're just driving around town Drag cars will not fall out of their power bands, since they're WOT all the time.

If you want a street car that has low/mid/top power......compound turbo is awesome. Bring it at the drag track...it will still be awesome. Bring it to time attack or autoX...it will still be good. If you have one, you can enjoy those events with a compound set-up.

And the two cars that you are trying to race (big turbo vs compound)...it is kinda unrealistic tho. A compound turbo set-up will have a tq that will come ALOT sooner. Their powerband will be soooo different Only thing that will have the possibility to be similar is peak power

Anyways, I know that in AutoX....compound will kill the big turbo no questions asked.

1/4 mile.....it will be a toss up

Road Racing.....I'll go with compound....