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Why do twins have lower drive pressure than a single?

7K views 26 replies 18 participants last post by  adeso 
#1 ·
As the subject states, why do twins usually have less drive pressure than a single? I would think it takes more pressure to drive two turbos than one. Insight?
 
#3 ·
Just because they do! haha no i have no idea but someone alot more intelligent than us will come and set us strait!
 
#6 ·
good point you bring up!
 
#7 ·
How exactly is a rainbow made? How exactly does a sun set? How exactly does a posi-trac rear-end on a Plymouth work? It just does
 
#17 ·
x2^^^ the way i understand it is like this- with just a single stock charger when the exhaust comes out the manifolds and then up the uppipes into the exhaust housing of the turbo, so that little turbo can only use so much off that exhaust to spin the charger so the rest off it is kinda just backed up creating what we call drive pressure. Im guessing that when you run 2 chargers it reduces this effect because you have another bigger charger sharing that exhaust flow and therfore it can not build up so much pressure. Understand i know nothing about turbos and this post was just a shot in the dark as to how it works, hopefully trent or scott or rob will chime in here and desribe exactly why DP is reduced in a twin setup
 
#19 ·
The drive pressure is less bc the air that enters the stock charger is already pressureized by the aptmospheric charger...........

Thus it has to work a lot less harder to reach desired boost levels. So the vein position is pulled way out allowing as much air to flow through it and into the atmospheric charger resulting in low egts. With non vvt chargers it is done with exhaust housing/wheel choices to match fueling......

Not to mention you can burn more fuel that is injected resulting in a more efficient burn thus less energy is lost in heat through the exhaust............

And timing is generally pulled back a little so that helps also...............

It's not just one thing really it is a combination of several factors thats end result is the same power with lower egts............
 
#22 ·
Look at how a jet engine compresses air in stages and in turn has the stages of the turbine section driving the compressors. Multiple stages allow unbelievable compression ratios.
If you look at an old T-37 “Tweet” trainer engine (single stage) it looks very much like a huge turbocharger.
Twins are a two stage setup that takes place at different locations.
I wonder if anyone has tried a multistage single turbo?
 
#23 ·
Isn't the new Garrett on Fords somewhat like this...........

It has twin compressors and one exhaust housing...........
 
#25 ·
how does the posi unit in the rearend of a hemi work? IT JUST DOES hahaha
 
#27 ·
I have no way of following though though, just ideas lol
 
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