.63 or .82 A/R ??

[Justin..]

dont know which to get on a T3 exhaust side of a turbo im looking to buy, anyone know which would be better suited?

[Smudger]

i lil bit of info for ya,

The A/R ratio of the exhaust housing refers to the size and shape of the scroll that is cast into the housing. It basically determines how restrictive the housing will be, versus how quickly the turbine will spin up. A lower A/R ratio (smaller scroll area, A) results in a more restrictive housing. This restriction speeds up the exhaust gasses and increases the amount that the gasses will expand. It's the speed and expansion of the gasses that causes the turbine to spin. So with a low A/R ratio, the turbine will spin up quicker, but as engine output and rpms increase, the restriction of the housing begins to build up too much back pressure on the engine, which reduces performance. A good rule of thumb for when there is too much back pressure is when the pressure in the exhaust manifold is more the half of the pressure in the cylinder. So basically, a larger A/R ratio will improve your engine's top end, while losing some mid range power and increasing turbo lag. A smaller A/R ratio will help the bottom and mid-range, but may effect the top end.

so really depends on what you want to go for, its difficult to tell which will work best on the engine you have (is it a 1.8 or a 2.0l?) but i would have said the .63 would be the best but some of the guys currently running turbo conversions might disagree and say the larger a/r is the way to go.

[Justin..]

its a 2.0 bbpt engine. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=120211050993&ssPageName=STRK:MEWN:IT&ih=002

unsre as howfar i want to take it because of gearbox reliabilty

[midge]

will be good to see this! should be in the 300's?
use a 172 box

[Justin..]

been searching for ages to get one and i need a cup one aswell because of the mechanical speedo drive? or are all 172 boxes mech drive?

[MAXIBOY]

hi mate give vince a ring at CR turbo,s too. he will give you a good price on them too.

http://www.crturbos.co.uk/

[Justin..]

cheers ill do that. any idea on what would be better? im still undecided

[MAXIBOY]

Q) How much boost will this engine run?
A) A very common question, but one that can only be answered in regard of what other parts you have fitted i.e. Turbo, intercooler and ECU? Simply these components (rods and pistons) have been used at over 3 bar of boost on other 4 cylinder 2.0L Turbo applications. We have used them in house to 385BHP, have not gone further due to traction and transmission (450BHP should not be a problem?)

nice... :D .......i,m this spec and above

[Justin..]

lol i would be nice to see that but i dont think my bank would :lol:

[Crossers]

I can't see how so much power is usable in a Willy!

Mine, i'm concluding, is too powerful; wheelspinning in 4th in the dry is just crazy! Sure its fast, but it needs toning down a touch. I have to really concentrate when putting the power down, firstly to stop me floating off the road, secondly to keep some tread on my tyres!

There's no need for a huge turbo on these cars mate, T3 i think is too much.

Paul

[MAXIBOY]

hmmm l.s.d

[Smudger]

if it where me id be tempted to go for a large T25.

quick spool up will still power up nicely through the rev range and will produce a healthy amount of torque.

Some thing around the 230bhp mark would be plenty with the same amount of torque would be quick enough

[stan]

hmmm l.s.d


hmmmmmmm LSD :D

[Coops]

.63 mate, larger would be silly, mines a .63 iirc and its laggy as hell at 250bhp already :oops: :lol:

[Justin..]

:D .63 it is then :D

[dhay14]

.63 for a 1.8
what about for a 2.0 Low compress?

[105epwr]

dont know which to get on a T3 exhaust side of a turbo im looking to buy, anyone know which would be better suited?
i think both may be to big ie LAGGY i ran a .48 on my rs turbo which was laggy it was 242bhp with a peak boost of 26psi and held 24psi stage 3 cossies run .48 and will flow 300+bhp
a .48 comes std on 4wd saffs thats my opinion anyway

[Justin..]

.48 wasnt an option with the t3 ex housing thought?

[Coops]

mines t28, am not sure on a:r now, i will have to check and get back to you mate tbh :oops:

[kj16v]

Whether it's a T2x or T3 doesn't matter. It's the trims and a/r's that decide it. Definitely best to speak to a turbocharger builder and explain what characteristics you want.

BTW if you go for a T3 then you can get them very cheap from the US. Much cheaper than yu could here.

[Justin..]

i looked into it but import tax would be a silly amount

[Justin..]

i looked into it but import tax would be a silly amount

[105epwr]

.48 wasnt an option with the t3 ex housing thought?
On a standard rs turbo the a/r housing is .36 on the t3 and a stg 3 hybrid runs the .48 on a t3 for the rst as i said its std on the 4wd saff cos!

[105epwr]

oh yes was runing a 60trim comp wheel as well=was very laggy ie nothing below 4k.
if you get mappable management with a anti-lag facillity then you are talking!!!! :twisted:

[Crossers]

Mine's .48, but not that laggy .

Paul

[kj16v]

oh yes was runing a 60trim comp wheel as well=was very laggy ie nothing below 4k.
if you get mappable management with a anti-lag facillity then you are talking!!!! :twisted:

That's not lag your talking about there. That's the boost threshold and anti-lag won't help. Everyone gets lag mixed up with boost threshold but two completely different things.

Mine's a T28 with (IIRC) .86 a/r exhaust housing and, like yours, it's not up to much before 4000. It's not particularly laggy though.
I have a manual boost controller - as opposed to just a bleed valve - and that really does the job. brought the boost threshold down by 200 rpm.

[Coops]

to clear it up, threshold is where it starts making boost, lag is how long after this threshold it makes full boost aint it?

[Justin..]

Aye that makes sesne to me coops

[kj16v]

Nearly. lag is the time it takes to spool up between gearchanges while it's above the boost threshold

[Crossers]

.86, thats rather large!!

Mine's good at just after 2000rpm, prob due to the small housings i have.

Paul