Jump to content
SAU Community

Recommended Posts

From what I know a twin turbo is generally setup sequentially - ie one smaller turbo that kicks in sooner, and a bigger turbo that kicks in a bit later... much like the Subaru B4...

a Bi turbo is 2 same size turbos kicking in same time etc.. etc...

Whats better for which application?

The GTR is setup as a Bi-turbo (2 same size turbos kicking in same time)...

Has anyone set it up as a twin-turbo (say a HKS 2530 and a HKS 2540)... is it possible?

Anyone know how it would go?

Link to comment
https://www.sau.com.au/forums/topic/41930-twin-turbo-vs-bi-turbo/
Share on other sites

I know it says Twin Turbo under my bonnet....

Ok i may be wrong, just what i read somewhere about the definitions, can't remmeber where...

Was just interested to know if anyone ran a sequential setup... what the pros/cons are

Maserati are about the only ppl i know of that refer to twin turbos as Bi-turbos. Sequential turbo setups usually have common exhaust housing, and depending on the rpm/load etc a valve switches the flow of exhaust gases between the wheels, or variatons of.

I wouldnt go running a 2530 and a 2540 on an RB26, each fed by 3 cylinders. Have you seen how some aftermarket manifolds using balancing pipes, on a equal size twin setup may not be so critical, on a setup using different turbos it would be critical.

The back pressure would vary between the front 3 to rear 3 cylinders, meaning you would need an ECU like a Motec that could tweak MAPS for individual cylinders, as the scavenging effects of the sets of cylinders would likely vary.

What you are better doing is doing what tractor pulling competitors do and use series turbocharging...which is where the the first smaller compressor pressurises the air into the inlet of the 2nd larger turbo, whilst the exhaust gases are similarily plumbed into one another

Think of turbines on a jet, where they are multi stage compressors... this approach tries to copy that. But again on paper it works better then in practice due to the plumbing requirements, inlet temps etc etc, unless you are using trick fuels, and a tractor engine that due to its low rpm can run massive boost... you get the idea

The advantage of using twins is that you can still have high levels of flow (cfm) from smallish twin turbos, and as the wheels sizes are smaller, lower inertia etc etc can still be responsive despite each only beign fed half the exhaust gases. Then you look at the larger turbo with similar cfm capability as the wheels of the bigger turbo have higher inertia, meaning they need more cfm to spin the buggers... but this is also influenced not just by the size/weight of the wheels but the pitch of the blades/wheel design etc etc.

Basically like all engineering, its a matter of compromises, and seeing which best suits the requirements, withoug impinging on the negatives too much. Just thoughts...

The term Bi-turbo is just a bit of Euro-English...

It is like AWD vs 4WD, they really don't mean anything different. Really.

It is all just marketing. As I recall Mazda called their sequential setup

a Twin-turbo...

The Porsche 959 has an interesting take on the twin-turbo setup.

It had two equal sized turbos but it would only use one of them

(spooled up by the exhaust of all six cylinders) then it would

switch to both of them... Apparently it worked quite well.

I suspect setups such as on the Audi, Maserati and even the GT-R are

more to do with packaging than anything else. On a Vee engine a

turbo on each side just makes sense. Also a long engine like a 6-cyl

ends up with a big mess of pipes as a manifold.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...