Any Good Low Boost Single Turbo?

[bradsm87]

-9 would be the better choice for 300 wouldn't they?

roughly around the 15psi mark is all you should need given a 2.6 needs around 18

this is all subjective as head and flow have a fair factor here too.

Yeah the -9's are another option to consider but I'd prob prefer for it to make the power "easier" even if it means laggier. I like the 76 trim turbine wheel on the -5 which will mean less back pressure.

[bradsm87]

Look at the compressor map for the Borg Warner S300SX 83-75, I would be leaning towards one of those with the 1.00a/r twin scroll T4 turbine housing if I were doing what you are looking at doing.

Will look into it. Cheers.

[zebra]

Why are we limiting boost?

300kws no matter what boost will still have the same cylinder pressures so why have a laggy as shit Gt35R when you could have a Gt3071 which would give a much better torque curve.

Manifold boost is just that...its in the manifold...doesnt have much effect on cylinder pressures...that is what VE is about.

If you want to bleed of cylinder pressure reduce the lobe centre separation on the cams, or leave the exhaust valve open a little longer via the Variable cams the EZ30 has.

[paulr33]

i agree with zebra

get the smallest single you can get that will flow what you want

then boost is simply a matter of checkign the compressor map to find out what pressure = what flow

twins wont give you the response you want

ie

twins that make 300rwkw

single that makes 300rwkw

the single will come on earlier and make more response/torque

but the twins will flow more progressively in the top end

so you basically want the smallest big single with a housing that doesnt choke vs twins or a larger big single

[badhairdave]

A little left field; nugget 3040 (3082), something i normally wouldn't recommend.

big comp, small turbine and .82 housing to try and get some response out of it.

you'd be skirting the bottom of it's peak island but the 82mm 56T compressor in .7a/r cover will flow 50lb/min at 1.75 pressure ratio and only just drop below your 70% target.

You aren't pushing the shit out of it so the smaller turbine with smallish housing wouldn't be choking it up, maybe even consider a 1.06 twin scroll, so exhaust back pressure should remain reasonable.

The mismatch may make it a bit lazy, but the high comp should make up for it.

???

i dunno, just thinking out loud...

[Lithium]

The logic is sound, but in my experience the lag/response of a GT3082R is so close to a GT35 that you may as well go with a GT35 and have the better match and even less MBP... just my opinion.

[bradsm87]

i agree with zebra

get the smallest single you can get that will flow what you want

then boost is simply a matter of checkign the compressor map to find out what pressure = what flow

Doesn't work like that. The 3L motor at high boost will try and push itself way off the map at high boost on a small turbo, getting way to hot. It won't just stop where I want it to stop.

[Rolls]

Why are we limiting boost?

300kws no matter what boost will still have the same cylinder pressures so why have a laggy as shit Gt35R when you could have a Gt3071 which would give a much better torque curve.

Manifold boost is just that...its in the manifold...doesnt have much effect on cylinder pressures...that is what VE is about.

If you want to bleed of cylinder pressure reduce the lobe centre separation on the cams, or leave the exhaust valve open a little longer via the Variable cams the EZ30 has.

Completely true but higher boost generally results in higher intake temps which is what the issue here is, high intake temps with stock pistons and high comp = detonation which I imagine is the problem.

Personally I think you are simply asking too much, there isn't any easy way to do it that wont result in either lag, or unacceptable intake temps. What is the main reason you are not keen to open the motor up? Cost?

Edited January 13, 2011 by Rolls

[zebra]

Completely true but higher boost generally results in higher intake temps which is what the issue here is, high intake temps with stock pistons and high comp = detonation which I imagine is the problem.

Personally I think you are simply asking too much, there isn't any easy way to do it that wont result in either lag, or unacceptable intake temps. What is the main reason you are not keen to open the motor up? Cost?

Simple Soulution...

WMI

[bradsm87]

Yeah cost, time, and the risk of it being not done right.

I know I'm sort of asking a bit much based on what's out there but it's a shame because if they put a bit of r&d into specific low boost compressors with the technology they have today, there could be some really good options out there. Rotary owners would especially benefit hugely from such a turbo.

Edited January 13, 2011 by bradsm87

[Lithium]

To do it you need a bigger compressor, I don't think there is any cheating that... so essentially you need to look at something like a GT4094R or bigger which it sounds like is pointless.

However, imho you are trying to perform a pointless match, you don't NEED that wide an efficient compressor map as I doubt the EZ30 is going to use it. I reckon a GT3582R would be fine, just tune it suitably and put the least restrictive possible hotside on it. Use alcohol, and keep the mixtures fat. If it breaks, and its tuned sensibly - its because its a weak motor.

[Rolls]

and put the least restrictive possible hotside on it. Use alcohol, and keep the mixtures fat. If it breaks, and its tuned sensibly - its because its a weak motor.

If you are running low boost wouldn't you want the most restrictive hot side on it? As if you only run 10psi you want to get it spooled as fast as possible and 10psi isn't going to choke even the smallest gt35 hotside? and surge isn't going to be an issue as we are only running low boost (I think).

Edited January 13, 2011 by Rolls

[bradsm87]

If you are running low boost wouldn't you want the most restrictive hot side on it? As if you only run 10psi you want to get it spooled as fast as possible and 10psi isn't going to choke even the smallest gt35 hotside? and surge isn't going to be an issue as we are only running low boost (I think).

Nah because then the plenum to exhaust manifold pressure ratio will be shit, no matter what boost. Like at full noise at 13psi, there might be 20psi in the exhaust manifold with a .63, 15psi in the ex manifold with a .82 and 12psi with a 1.06.

[Rolls]

Nah because then the plenum to exhaust manifold pressure ratio will be shit, no matter what boost. Like at full noise at 13psi, there might be 20psi in the exhaust manifold with a .63, 15psi in the ex manifold with a .82 and 12psi with a 1.06.

sure but at what point does it become unacceptable for tuning?

[33GTRV]

Take some advice from me, i have had ALOT to do with these engines. I had a S/Charged EZ30 in my brumby. The motors themselves respond extremely well to a small cam upgrade and exhaust, and depending what model outback you got it from, a snorkelectomy. As for forcing it, unless you are prepared to throw some serious money at it, dont bother. I had walking cylinder liners, never ending headgasket failure, cracking valve seats ect ect. Keep it N/A, carry out a few simple mods and reap the rewards. PS, the knock sensors in these engines are particularly sensitive, especially the drivers side one. Good luck on your endeavours

Cheers, Allan

[bradsm87]

Faaark that sounds scary!

Tell me more about yours when it did work. what supercharger did u run? how much power?

Cheers

Edited January 13, 2011 by bradsm87

[33GTRV]

hey brad. I ran a vortech on a custom bracket, i had no aircon so i used the aircon mounting bracket holes on the top of the block. To get it in i had to run an oil cooler where the radiator was and i ran a vz Gen 3 radiator mounted in the boot. HP figure was an unknown, never had the thing dyno'd. We made up a custon billet adaptor plate to go from the EZ30 to a GC8 wrx 5 speed and ran a MRT centre spool for rwd only. was a very fun piece of gear, used to rip some of the biggest skids ive ever seen and was pretty much death with doors in the wet. We adapted a megasquirt to run it all and i can safely say, ill never ever ever ever ever do that again, was a pita. If you have your sights set on Boosting one of these i have been chatting to a mae of mine and he seems to think u may get away with a S/Charger and low boost, about 6psi. Give the bump sticks a quick regrind and get some headers made with a 2 3/4" exhaust and a rising rate fuel reg and you could run it of a factory computer. If you dont mind me asking, whats it going in?

Cheers, Allan

[bradsm87]

I'm buying a 2007-2008 Liberty 3.0R Spec B wagon. Will start off with handling mods. I am pretty set on boosting for the power delivery. Maybe a good efficient supercharger is the go for reliability. That way the only thing limiting backpressure is the exhaust. A new Whipple W100AX has a peak adiabatic efficiency of 81% which is higher than any turbo so charge air would be cool. Team that up with a big water to air intercooler and it could be a winner. I would actually like to gain some experience with superchargers.

It would look tuff with a GT bonnet cut out under the scoop with a visible supercharger hanging up into the scoop!

Edited January 16, 2011 by bradsm87

[33GTRV]

ahh. we have an outback 3.0R premium with the same engine and 5speed auto as the specB's for a soccermums car. The missus wont let me play with it too much as she has seen what happens, it usually gets out of hand pretty quick. Be careful with the suspension mods as they are very touchy on the alignment side of things. Ive seen alot of cars with larger wheels and a set of springs destroy tyres fast. If you are looking into that area, i suggest a set of adjustable strut tops and a set of camber bolts for the bottoms. Make sure you get a good wheel alignment tech, not some 19 year old dickhead from bob jane that thinks a toe and go is all it will need. They are pretty touchy in the suspension dept so a full 4 wheel alignment after any suspension mod is recommended. Also, look into getting a set of equal length headers as the stocko ones are about as crude as they come. Good luck with it mate

[bradsm87]

cheers for the info mate. Yeah I have a local place with a brand new insane alignment machine and an awesome switched on bloke that operates it. Will get camber bolts for the front struts and offset bushes for the rear upper arms if i can't get the rear camber where it needs to be.

Yeah equal length headers will be a must if i go down the supercharger track.