Supercharging the Subaru NA engine

[turner_822]

I thought I would start this post for everyone to show what they did for their supercharger build so that those who are interested can see what can be done/needs to be done. I am doing this because when I was looking to do it (being new to cars) I found it very difficult to find an overview of what needs to be done.

I'll get the ball rolling...west_minist/Tradewind feel free to correct me. I don't particularly care; but if everyone keeps their posts roughly the same format it will be easier for viewers to scroll through the different builds/models. I did not include prices, if you want accurate prices (i.e. not out-dated) ask the providers/PM.

CAR
Model - MY08 Liberty 2.5i, 5MT, ADM (95,000km at start of build)
ECU - Denso (Pre-boost ECU Tuning done by west_minist of XRT)
Pre-Build Mods:
-2.25 inch cat-back system (X-Force) with universal hi-flow cat
-Lightweight/underdrive pulley kit (go fast bits). Needed to be replaced with non-underdrive pulley (Perrin) or it would have underdriven the supercharger.
-Cold air intake with K&N filter
-Front/rear strut bars

STAGE I
SC Kit
Raptor (ProStreet) Supercharger kit, including intercooler with 6psi pulley. Kit includes all components of the supercharger and intercooler with the exception of the mounting point for the mass air flow (MAF) sensor. This meant the blow off valve (BOV) pipe provided needed minor modifying. The kit also included 310cc fuel injectors which were just enough, anyone looking to go stage II should get better ones.
Extras:
-WRX mass air pressure (MAP) sensor (OMNI 3-bar)
-Tuning by west_minist of XRT (previous NA tuning meant that the supercharger tuning was discounted)
-For tuning I bought and installed the following gauges from Innovate Motorsports: Wideband (air:fuel), oil pressure/temperature, exhaust gas temperature (EGT)
Results
NOTE!! Tuning was still in progress, and now that injectors have been changed for stage II it will remain unknown how much power west_minist could have squeezed out of it. One un-confirmed gear pull showed 161kW

v4 SC Dyno.png (68.94 KiB) Viewed 5513 times

STAGE II
This is what I am getting for stage II, bearing in mind this is an ongoing process at the moment.
-From Raptor SC: a 9psi pulley for the SC and 2nd radiator for the intercooler system.
-From XRT: more tuning by west_minist
-From TechWorks Engineering: headers (4-1 HO) to complete the exhaust system and achieve hi-flow now the engine is boosted, and a valve spring/retainer kit for added reliability.

6.JPG (21.28 KiB) Viewed 5548 times

-STi Denso Pink Injectors (510cc rating, independantly tested to 565cc)
-Deatschwerks DW200 in-tank fuel pump (255L/hr)

Results to follow. Currently running the stock clutch so see what happens. If (or rather when) it fails I will research and considder what to do. A heavy duty clutch may result in something much more expensive breaking...like the gearbox!

Related post (containing all relevant website links):
http://forum.liberty.asn.au/viewtopic.php?f=15&t=18309

[west_minist]

I have a NA car and this makes me very excited. lol. Once everything hold together, I cannot wait to see the final results.

Cheers!!!

[SegR]

Good post Nick. Why the MAP sensor?

[west_minist]

Good post Nick. Why the MAP sensor?

To read pass 5psi.

[blademaster]

good write up.

Same again for preface Gen4s. However, if you have a preface Gen4 with a Hitachi ECU, you will either need a Ecu replacement or.... well I don't actually know the other option.
My Stage 2 pulley arrived!

Hey Nick, where did you mount your radiator? Got a pic?

[turner_822]

My Stage 2 pulley arrived!
Hey Nick, where did you mount your radiator? Got a pic?

I have installed my new pulley and been testing...having some serious fun. Tiniest bit smaller in size but makes a real kick! I am awaiting 2nd radiator and will post pics then

[west_minist]

SC Boost Comparison - 3rd Gear Dyno SAE.png (56.24 KiB) Viewed 5423 times

[blademaster]

Nick, what I can't seem to understand is the Torque difference between our cars. You are at 9psi and I am at 7 and you got 277Nm?? I am missing something =/

[jslayz]

Different dyno?
Tune?
Petrol?

J

[west_minist]

Addtional cooling is not in yet. Also maybe road, environmental conditions, etc. Petrol playing a part too. But when the cooling is added, let us wait and see.

[blademaster]

True (though both our cars should be running 98)

West did my tuning, and I gotta go back there once the new pulley is on. It is still a big difference though (and there wasn't much difference in kW @ 7psi)
and I need a service
and I need the fender ding fixed (sorry J, won't be on that cruise until I get the hideous fender ding fixed =P )

[turner_822]

True (though both our cars should be running 98)

West did my tuning, and I gotta go back there once the new pulley is on. It is still a big difference though (and there wasn't much difference in kW @ 7psi)
and I need a service
and I need the fender ding fixed (sorry J, won't be on that cruise until I get the hideous fender ding fixed =P )

I just had full service changing everything, went to iridium spark plugs (1 grade cooler as per Tradewind's instruction) and superlight shockproof oil (cant remember #) for gearbox and diffs. I always run 98, also octane boost/clean every few tanks but not when logging.

Only other major difference we have is ecu?? I don't have a clue about the differences between the denso and replacement you used. Have you done exhaust/cat?

[blademaster]

Yah I've done exhaust and cat; almost equal-length 4-1, 3in pipe and then Y-pipe to 2x 2.5in. Magnaflow centre and 2x Magnaflows at the back

My next service is going to be pricey as I want the clutch changed to the organic HD type.

[turner_822]

My next service is going to be pricey as I want the clutch changed to the organic HD type.

I am still thinking hard about my clutch...a HD clutch I fear will strain other more expensive bits like the gearbox. My mechanic and Tradewind feel ideally I would want something a bit tougher then stock; but NOT too tough. I plan to research a little while seeing just how long my stock clutch lasts. Hasn't missed a beat so far (5,000km) but I look after it and never put it under a heavier load then the stock engine would have dished out (well I at least try lol)

[blademaster]

The gear box should be able to handle it, I was running an Excedy organic HD clutch with my 5 speed @ 7psi, and I can't imagine another 20 or so kW breaking the gearbox/diffs. It is waay easier to launch the car with a HD clutch =)
are you getting any shuddering on take-off?