A simpler ( and less engineering mindfield ) set up would be one after the other, however using 2 standard turbos would possibly negate the whole affair, as Shifty pointed out, it probably wont have enough coming from the exhaust to provide both turbos enough spin...but the picture does show 2 turbos of the same size ( although i can't see the fins on both )

Which way around though?

Larger standard size first feeding a smaller one? would this be similar to a larger wheel turning a smaller wheel, ie the boost from the larger will create higher spin in the smaller one, therefore boost at a lower rev range?
 
Badger said:
A simpler ( and less engineering mindfield ) set up would be one after the other, however using 2 standard turbos would possibly negate the whole affair, as Shifty pointed out, it probably wont have enough coming from the exhaust to provide both turbos enough spin...but the picture does show 2 turbos of the same size ( although i can't see the fins on both )

Which way around though?

Larger standard size first feeding a smaller one? would this be similar to a larger wheel turning a smaller wheel, ie the boost from the larger will create higher spin in the smaller one, therefore boost at a lower rev range?
Click to expand...
Normally the smaller turbo spins pretty much all of the time from low throttle settings. Because of its size it cant deliver the volume of air at higher engine speeds to maintain full pressure so then the larger turbo kicks in. The small turbo is to try and remove any lag as the larger one spins up and starts boosting. The output from the small turbo does not drive the larger turbo. Both feed into the inlet manifold and are exhaust gas driven.
 
Last edited:
Badger said:
This is more of a shed idea than spending a wad of cash on a pre built unit :)
Click to expand...

I know theres setups you can buy to bolt on that are expensive...

But theres nothing stopping you from buying a second hand bmw 320d or 330d vnt turbo and making one of those work...i bought a 320d turbo for £120

Just think it would look neater and actually be effective! Either way will be watching with interest!
 
Shifty1962 said:
Normally the smaller turbo spins pretty much all of the time from low throttle settings. Because of its size it cant deliver the volume of air at higher engine speeds to maintain full pressure so then the larger turbo kicks in. The small turbo is to try and remove any lag as the larger one spins up and starts boosting. The output from the small turbo does not drive the larger turbo. Both feed into the inlet manifold and are exhaust gas driven.
Click to expand...

I was looking at a Mazda Rx7 twin turbo set up, although there isn't much difference between the sizes of both turbos, the second doesn't kick in as such until over 4k revs, but we're talking a petrol ****el engine, so i have no idea how that compares to an old 2.5 doosel!

4x4tom said:
I know theres setups you can buy to bolt on that are expensive...

But theres nothing stopping you from buying a second hand bmw 320d or 330d vnt turbo and making one of those work...i bought a 320d turbo for £120

Just think it would look neater and actually be effective! Either way will be watching with interest!
Click to expand...

It's good to know the vnt's are available as stock fittings as i can have a mooch around :D

wangie46 said:
Heres a utube link to a 200tdi with supercharger in a. Series
YouTube - Broadcast Yourself.
Click to expand...

I would love to supercharge it, but lets me get past the twin turbo idea first :lol:
 
*scratch's head.

It's all abit confusing in places, can anyone define what a ' smaller' turbo should be, ie from what size engine? I would've thought anything upto 2l would suffice as small enough for the lower range...

I've seen a K03 off a 1.8 Audi/VW locally for next to nothing, worth a shot?
 
i asked today my friend who has remapping shop and he said that it´s better to do hybrid turbo. playing with rotor sizes or sumfing... i dont know what is in english? some thing to do with a/r ratio ?
 
Hi Mr Badger, if you are thinking of splitting the manifold to drive two seperate turbo's, my initial thoughts are; would you not need smaller turbos?? My strange brain is telling me the amount of exhaust flow to each turbo would be halved, limiting the pressure created by them...:D
 
andlover said:
i asked today my friend who has remapping shop and he said that it´s better to do hybrid turbo. playing with rotor sizes or sumfing... i dont know what is in english? some thing to do with a/r ratio ?
Click to expand...

I pinched this, i was looking into all the a/r stuff:

A/R Explanation
A/R is the rated volumetric efficiency of a turbos 2 sections, so to speak. Imagine if you have a garden hose spraying water out at a pinwheel
with the hose open ended, the pinwheel spins okay. Put a nozzle on it an the pinwheel will spin like mad.

There are issues with the nozzle on the end, you lose volume but gain pressure. With the nozzle off you gain volume, but lose pressure and you can't turn the pinwheel as much.

Simply put, on small displacement engines a smaller A/R is better, on large displacement engine a larger A/R is better due to exhaust volume.

A larger A/R will spool later and provide a higher power band, if your engine is capable of reaching the RPMS it should be used in.
Click to expand...

:confused: I think it's to do with the size of the exhaust and the distance from the centre of the wheel to the centre of the exhaust inlet?

Chrisfrain2007 said:
I remember seeing summat somewhere about a turbo being spooled by compressed air/gas instead of exhaust
Click to expand...

Interesting, but carrying gas canisters around isn't that helpful :lol:

mad git said:
Hi Mr Badger, if you are thinking of splitting the manifold to drive two seperate turbo's, my initial thoughts are; would you not need smaller turbos?? My strange brain is telling me the amount of exhaust flow to each turbo would be halved, limiting the pressure created by them...:D
Click to expand...

A good point, however i have read ( it eludes me now as i have 30 odd pages open ) that an amount of gas/exhaust from the engine is wasted, but i'm not sure if this equates to heat loss rather then power as such.

But 2 x 1.25l turbos would in effect produce the same as a 2.5l turbo at a lower rev ( 2 x 1.25l @ 8k rpm = 1 x 2.5l @ 4k rpm ), so the balance of running 2 turbos could be down to, say, 1x1litre turbo and 1x1.5 litre turbo....but something tells me it's not that simple....
 
I am getting a garret t28 off my mates old 200sx. It has the same turbine wheel and housing, but larger compressor wheel and housing, more boost through the range. :)
 
if the turbo is too small it can create lot of heat, or two tbo:s , i had a volvo t4 and it creates a lot of heat when boost is 1.6 bar .... in peak. i think it´s gona blow..
 
Karlos28 said:
I am getting a garret t28 off my mates old 200sx. It has the same turbine wheel and housing, but larger compressor wheel and housing, more boost through the range. :)
Click to expand...


Have you got any more details on that one?


Anyway still looking into it, sounds like a novel way to spend some evenings, mashing together bits of land rovers to see what the result is...
 
Look up pro chargers if there was space to fit one I'd want to fit one of them :-D

I think you could fit another one, is there any point as I don't think it would aid the engine in any way due to a diesel engine working at such low revs.
 
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