Stavros

Anyone seen this setup before?! I hadnt until about 10mins ago, but meant to have been around for 30 odd years... 200psi boost anyone



Used on super-stock tractors for tractor pulling comps and stuff (banned in most turbo drag racing as its "cheating"), a turbo, blowing into a turbo, blowing into a turbo, and so on connected like in the pic, more turbos, the stupider amount of boost possible with decent efficiency and flow...

There meant to be plenty of books and info on it with all the formulas, and pressure and flow charts, etc.

I wont pretend i know any more about it as i dont yet, but bloody wanna find out, this mental

sunny

iTrader: (1)

Thats the LICK!




...aint got the space though.

Seriously it's a bit like twin engined cars...why use 2 when you can get 1 to do the job properly.

Stavros

Its somthing to do with efficiency or flow or somthing, there IS a valid reason for it, what that reason is im not sure yet

They could use a single turbo thats capable of the same power, but they use 2-3-4 all connected to each other instead...

Soon as i can find out exactly the fuck why il tell you

Cam

I have seen a feature on a supercharged and turboed Lancia that used the blower to reduce lag but never the above setup...hmmm interesting.

Cam

Mike Rainbird

iTrader: (3)

It's called "compound turbocharging". It will be VERY big in the Cossie scene later this year.... Don't ask me any more than that, as I ain't telling .

RS_Rawli

CossieRich

iTrader: (1)

How mad does that look.

Mint FRST

iTrader: (1)

The huge dumper trucks used for opencast mining have been using that setup for years I believe aswell.

Paul Eggleton

I also think some old plane engines ran something similar to increase their max ceiling(altitude).

wes

So is this the kind of setup Dumped has Mike? One smaller turbo feeding one huge turbo....

Markb_s1

seem to recall some mention of Martin H having an extremely large turbo as "one" of his on his new car somewhere too.........

caprixpack

sure ive seen that somewhere before



this is a zackspeed capri with a 1.7 liter kent crossflow engine with 600bhp

Mike Rainbird

iTrader: (3)

Yeah, like he could think up something that clever . Watch out for a certain engine in the back of an Ultima.... .

Porkie

iTrader: (1)

So Ahmed is doing it then...

foreigneRS

very interesting

Jim Galbally

why bother putting a mad engine in a bug eyed ford scorpio

Disabled Account

You serious Jim????

Disabled Account

http://www.ultimacars.com/

Jim Galbally

course not

Stavros

compound charging is supercharger and turbo aint it mike, not what i put.

capri bloke- err, look at the pic you posted, its just twin turbo, nothing like what i posted

Mike Rainbird

iTrader: (3)

Steve,
Compound "charging" can be done with either a supercharger or two turbos, but it it where the air from one is fed into the other and is why it is called "compound" charging. I suggest you do a "google" search if you don't believe .

kennert

That looks rather funny
Samll lag free feeding a gt 40 then ??

Cheers Kennert

Stavros

yea alright cleverclogs

is there anywhere that fully explains how it works tho?

i know it has to be a bigger turbo feeding a smaller one, and so on, but have no idea barring that

kennert

http://www.vehicular.isy.liu.se/Publ...3443_OF_MG.pdf

IT's a 64 page scania study of compundturbocharging. BUT the secund turbine drives the crankshaft through an oil cupling of some kind.....

I too would like to read more about this compund charging?

Cheers Kennert

Stavros

from what i see written, say you wanted to run 3bar, both turbos only "sence" 1.5bar each, but it equals 3bar overall, which i doint get really

also says it had to be a bigger one blowing thru a smaller one, but no idea on size differences (dont look much in the pic i posted)

and how would it turn out, would you run a T34 blowing thru a T3 and itd have the combined lag of both, or what? (id guess not as the exhaust gas isnt split between them, the exhaust gas goes thru one then the other, maybe itl have the lag of only slightly more than the smallest one if it was on its own, fuck knows ).

did a goodle search and theres very little REAL tech info on it on the net , most of it is crap from people who dont really know, most of them mixing it up with sequential turbo setups.

from what i can see the reasoning for it is above about 40psi even the best turbo is no good, and turbos blowing thru turbos doubles it all up

says it makes charge temps huge tho, which is understandable, and surely power would still be limited by the flow of the smallest turbo exhaust housing! Tho i guess you could run a huge wastegate or 2 to bypass it.

kennert

what I don't get is if the little turbo boost low down and the big takes over.....how will the big turbo boost more air when it's coupled with the small turbo that by nature can't deliver that much air ????????????

ADUSR33

steve dont get any funny ideas

Rob

because the smaller turbo is being feed pressurised air, where on a "normal" single turbo setup it would be having to draw in air at atmosphere

Flow characteristics will change

Rene

seems odd to me as you would be well overspeeding the smaller turbo

Stavros

adus- dont worry, i wont, tho id love to know how this works. bearing in mind it seems to only be of use when running 40psi+ its only really good on diesels, where modded ones can run 150+psi boost

rene- i thought that but i think its the other turbo blowing thru the smaller one, the smaller one dont have to be at the same speed- look at a turbos housings, there a LOT of room between the wheels and the housings for airflow thats nowt to do with the wheels, they not a positive dispacment device

SeanT

The best way to do it is smaller one blowing through bigger one until certain rpm where a valve opens to let more air into the bigger one. You get the ultimate power of the big one and the lag of the small one (but a "lump" on the changeover unless very carefully set and adjusted) With a small engined car (ie. less than about 4 litres) it's viable to replace the small one with a supercharger to minimise lag.

Stavros

no, thats not the best way, its just a way, infact binning a sequential setup like you mention is one of the FIRST mods they do on RX7s and Supras that have that as std

the only way to run megaboost is this staged setup

Rene

Steve i can see you point on the housings being so far away but isnt there still a bit amount of air going from turbo to turbo ??

and what do i mean by "they not a positive dispacment device"

You are right on the binning the first 2 fookers on Supras and RX7's though

kennert

having the small turbo last seams really wierd to me.??????????????

Markb_s1

same here, but if you look at having it the other way round that doesn't really make sense as far as ultimate performance goes.

Stavros

well they used on vehices running 200psi boost and over 3000bhp so i think they know more about it than we ALL do

unless you want to go disagree with them

SeanT

Sorry, wasn't paying attention to the first post, so, one turbo drives the other then....
One way to keep ACT well down!!

foreigneRS

tractor pulling is so cool. but if i had 3000 bhp at my disposal, i'd be using it to accelerate, not to pull a lump of iron through a field

Thrush

iTrader: (1)

I always thought that one turbo blowing into another, bigger, turbo then onto inlet plenum was sequential turbo's????

How is this different then? (not disputing, just don't get it lol)

Stavros

no, sequential setups are different, and vary depending on the application, but NONE of them blow thru another turbo, they all blow into a common pipe after the turbos.

Thats the difference with this setup, its NOT made to decrease lag or whatever like sequential setups, this is to be able to do extreme boost levels that isnt possible with a single turbo.