inline engine twin turbo knowledge needed
Turbo Mini Forums

ok so ive been looking into how they set-up twin turbo's on inline engines and by looking at a picture of a lexus/toyota soarer the simply split the manifold.

in theory easy. but when we are talking mini wise (8-port or 16v head) would it not be a downfall only having 2 cylinders worth of exhaust gas to push a say t3 turbine?

i am going to run a t15 for rapid spool up or maybe a t2 (still planning to be honest) and then a t3 for the higher boost (possibly bigger to make it worth while but that is all money permitting)

i am just worried about the lack or reduced amount of gasses to push the turbine on the t3 or bigger side of things. would this hamper the whole set-up making it hard to get it too spool up and/or make make decent amounts of boost?

sorry that its a bit long winded but ive been looking at this for days and i have found alot of answers but there are just some things i need a more expert answer on such as these questions.

Cheers in advance, James.

Edited by James_H on 6th Aug, 2007.

Is it better to go the turbo/charger route? Only an idea, know jack about how to approach it.

yeah i was looking at this earlier also. i read that you end up going down the route of LOTS of plumbing and there is the fact of needing a 1-way valve in line so as that the turbo can pull that open under vacuum when it wants more air than the supercharger can let through and this makes it really restrictive. to get over this you can have two actuated valves to close off the supercharger and open a direct path to the turbo but then you are getting into even more plumbing and space etc etc.
and before anyone says..yes i know that twin turbo isnt exactly going to be easy to fit into a mini engine bay but i will be doing all i can to give my self more space and also save space in the construction. such as turbo box, full length webber box and the rest of it. i think that a twin turbo would work out better for a 16v mini due to the fact of less plumbing than a t-s/c and SLIGHTLY less space to taken up. i was just wondering if 2 port per turbo issue would be a big problem and if so if anybody has got any ideas to overcome this?!

damn do i ramble!

is there any need though? the a-sereis is a small lump, with the selection of turbochargers avaliable there will be soemthing sufficiently small for fast spool, but still efficient at high enough pressure ratios to produce serious power, all for less cost weight and complexity of 2 clunky old turbo's :)

for referene the msot common twin turbo setups i come across are RB26DETT, 2jzGTE and whilst not inline its setup is interesting, the EJ20 twin turbo subaru lump, googlin that shoudl brign up some good reading material :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Hi,
I don't think this will work on a small cc engine. With careful setup and turbo sizing it shouldn't be too much of a problem. Hopefully some of the 16volt people will help you out with this one.
What sort of use / power are aiming for?
Cheers,
Gavin :)

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My Mini build diary

well i have just blown my own plans out of the water as i have just seen fastcarls kad turbo and that gives the sort of figures i was looking at (more to be honest) and so its sort of abit pointless having two turbo's when i can get the power from one. have been reading alot of turbo build projects lately also and with the a-series it seems that not much boost is needed on a decent set-up to produce decent power.

my intentions where as a road going track car. i think that i may go single t3 or maybe gt28 (i think??? ball bearing t2-t3 hybrid??) money permitting, but i am still interested in this so would still love to hear the general opinion on it and any more info anyone has.

also if fastcarl could give any info on his car(i know its pure race set-up(well i think) but hey) such as what size turbo he has on it and the spool-up rpms etc etc that would be great

Cheers again everyone

I'm running 180banana's at 14psi at the mo on a 5 port, still more boost to go yet on a fair sized turbo.

it does however spool up very low down and is easy to keep on the boil.

i can imagine once i get the 16v head on it will improve some more although i dont know if low down torque will suffer.

i'm definately along the lines of the right sized turbo is more than up to the job with virtually no lag and enough capacity 200-250bhp.

Consider this:- A supercharger being blown through by a T3. Between the turbo and blower is a valve which opens under vacuum. This allows the supercharger to suck. You also have the supercharger geared very high, so that it is efficient still at low revs. As the turbo starts blowing, the pressure diff across the blower approaches zero AND SO DOES THE POWER REQUIRED TO DRIVE THE BLOWER. So, you have all the bonuses without all the pipework. Fitting all in will be fun though. It would be doable though.

Bugger off, I'm getting there.