sc14 supercharger info?

[nick.parker]

Yep,

Better to keep the SC speed lower and it will last a LOT longer. Around 15psi on my engine I think is reasonably comfortable for the SC14. On yours this same SC speed (2L not 1.6L) would give around 9-10psi. You've got to think about what you want to happen at cruise too if you car is a daily driver.
For a while I had some moderate (267) cams and torque was reduced a fair bit around 2000-3000 (cruise speed in AW11). And it was so annoying, to do 100k's on the freeway, the manifold vacuum had to be needed to be 80 - 90kPa which was above the superchargers 'turn on' threshold at 70kpa. And moving the threshold higher results in a kick in the back when the SC engages...I went to milder cam setup in the end and now its cruises at and above 100kph with less than 70kpA. But then my engine is 1.6L and 8.0:1 compression too.

Cheers Nick.

[brett_celicacoupe]

the car probly will be a daily driver but the SC will only be operational when i need to be going fast.....so through traffic, ill prob just leave it off and open a 1jz TRC TB to act as a bypass.

this should prevent the belt from being stressed from OFF/ON switching. what i plan to happen is the SC will turn on, then 1/3 of a second later, the 1jz TB will close. this should bring the boost on smoother instead of BAM, 10psi

however the SC will only turn on when the vacuum reaches a certain point

another question;
when the SC kicks in, is it a massive jolt to the system?

[mic*]

I need to go measure my crank pulley coz i dunno what size it is but it is a standard 1G-GZE crank pulley. The SC14 pulley is now 94mm.

With standard cams, I make up to 15.5psi (~4500-6500), building from 14psi at 2000rpm. I can boost harder, quicker, but the car just doesnt respond (as) well by going WOT at those revs.

Brett, to turn the SC off at higher revs i am assuming you wish to clutch the SC? When i fitted the Falcon A/C i fitted the electro clutch too. Even the Clutch face bolted hard up against the pulley + electro magnet could not hold more than 12psi before slipping - revs didn really matter (until like 5500) but hit 12psi - big squeeling noise. I kinda knew it wouldnt hold but wanted to know fer sure.

So my point is it will be hard to clutch the kinda pressure ratio's you want. Something to think about.

Rick, my theory as to why the SC gets so hot un-bypassed under vacuum is; pressure ratio. The SC is essentially trying to pump an absolute vacuum agaist the TB (excusing the little idle bypass). I imagine there would be VERY low instantaneous pressure pulses at the inlet of the SC. It would be working quite hard with even less air molecules to carry away the heat. With the bypass some of the air goes round in a circle but the pressure ratio across the SC is mroe or less equal so less heat id generated in the first place, and there is less price at the crank to drive the SC.

I now have my factory ABV hooked up to a post SC vac/boost line, with a restrictor in between. Works a treat

[mic*]

the car probly will be a daily driver but the SC will only be operational when i need to be going fast.....so through traffic, ill prob just leave it off and open a 1jz TRC TB to act as a bypass.

this should prevent the belt from being stressed from OFF/ON switching. what i plan to happen is the SC will turn on, then 1/3 of a second later, the 1jz TB will close. this should bring the boost on smoother instead of BAM, 10psi

however the SC will only turn on when the vacuum reaches a certain point

another question;
when the SC kicks in, is it a massive jolt to the system?

My clutch used to kick in just before zero vacuum which seems to be pretty late compared to 4A's? And yes there was a jolt, not massive. I was constantly hitting the clutch point at whatever throttle position, then having to back off the throttle for smooth "daily driving" .

I much prefer the drivability of constant drive... But it is gonna shorten my chrger life...

[brett_celicacoupe]

im also wondering if you need some sort of pressure release valve for the intake piping when the TB closes?

plumback ofcourse

[mic*]

im also wondering if you need some sort of pressure release valve for the intake piping when the TB closes?

plumback ofcourse

If i understand you correctly, the answer is;

No. SC is post TB on a 1G. But as you still need a bypass around the SC to stop the heat under vac. Its just circulates at a low pressure then, relatively even pressure accoss SC inlet/outlet and therefore minimal crank loss...

[mic*]

Also, in regards to above post. The belt spins constanlty coz the crank does... The pulley spins on a bearing on a boss which bolts to the SC. A splined shaft goes through all that and has a "clutch face" bolted to the end of it. This will be stationery (SC not spinning) unless and elctromagnet in within the pulley is engaged, and then the clutch face is forced to stick to the spinning pulley and drive the charger.

I have been trying to think of a way to have a smaller pulley (ie my EA pulley) yet still have clutched operation. As you spin the SC harder, the clutching force required goes up. Yet the space you have to house the magnet is smaller... The only obvious solution is an impractically big crank pulley. And even then, the capacity of the standard clutch has not increased with the load...

Anyone know if you can step up the voltage without frying the electromagnet - i assume its 12volts stock? Scary thought tho coz the EA one pulls about 3.5 amps and its like half the size of the SC14 E.M...

[brett_celicacoupe]

how about changing the material used on the clutch face......i was thinking something along the lines of a motorbike clutch disk.

[AE101LEV]

im curious to know the sorta qtr mile times with a SC14 on a Gze does (on average)

[mic*]

im curious to know the sorta qtr mile times with a SC14 on a Gze does (on average)

Dunno coz mines on the 1g twas built for... sorry. Ask Nick.

Brett,

Just for your interest; After the EA pulley slipped (as was highly expected) against the standard clutch face - even tho the the clutching material parts lined up - i bolted them hard up against each other.

It still slipped + 12 psi or + 4500rpms.

So, in true no-patience-wana-drive-it-now-so-to-hell-with-it style, i unbolted the clutch face, took it off, covered it in 2pac epoxy and bolted it back up hard. This was great for a week. Then the epoxy cracked as you would imagine.

Since i loved the drivability of permanently driven SC, and the economy was not greatly affected i got it welded. I removed the surclip retaining the pulley and had the face tacked to the pulley whilst on the car. Then removed it and welded it up.

My SC is now borderline fucked after a week. The reason: The hole for the spline in the clutch face was not perfectly centred somehow which meant the lobe shaft bearings got a flogging, and Ive got teflon all thru my intake

Joy.

[mic*]

Anyone got a spare SC14 laying around...

[nick.parker]

If you look on MR2OC (as in www.mr2oc.com), a guy there ran a 13.5 with an SC14 and about 18psi. While the SC14 doesn't enable monstrous HP figures, the drivability is better than great and low end torque just insane from a 1.6L. I ran my SC14 setup at 18psi for six months and the low/mid torque was heaps of fun. Not much on the street can acelerate as hard just using the gas pedal off idle revs with no clutch dumping.
Cheers, Nick