sc14 supercharger info?

[TRAV-KE55]

Just wondering what performance people have accheived with these and at what boost levels, what engine, air temps etc.
any info appreciated., thanks guys.
Trav

[nick.parker]

Hi,
I have an SC14 on a stock bigport 8.0:1, 4AGZE (with custom ECU). Its running 12 psi, with a custom cam combo, 60mm throttle, 2.75" pipework (overkill) . This setup gave 15psi on stock cams. I dyno'd it at 150rwhp before extractors, 2.5" exhaust, custom cams and much better fuel mapping. Now I'd estimate I have about 165rwhp. I need to dyno it again.

This boost is achieved with stock crank pulley and 120mm retro-fitted SC12 pulley onto the SC14. Don't know the SC outlet temp, but after my water to air the inlet air temp is usually around 40 degs C. I should get my thermocouple out and become horrified!

Cheers, Nick

[mic*]

The SC14 as the name suggests, displaces 1.4L of air per rev. I would not reccommend a pressure ratio over 1.9:1 or shit will get REAL hot. Roughly i'd guess dont spin it any harder than 15,000rpm.

I have a factory 1G-GZE. I have put a 94mm EA Falcon A/C pulley & clutch on to a custom boss to mate to the SC14 for a bit of extra fun/heat.

Nick; i measured (top of peak) diameter for the standard SC14 pulley at 128mm. Sound right?

The smaller pulley made 12.5psi, up from the 9.5 stock. I have now eliminated the ABV and can make 13.5-14psi. I have a pre-charger WIIC (water injection) setup which i have not measured any results from yet, but i can say; it does not make any real difference to performance (stock ECU), but the post charger pipework is cooler to touch after an equivilent quick thrash. Need a thermocouple...

Anyone who is interested in the adapter boss to bolt the EA setup straight to the SC14, PM me and i can get you the tech drawing, or have one fabbed.

[nick.parker]

mic,
Yep thats sounds about right, people usually refer to them as 125mm....not sure where measured though. The SC12 have either a 125mm pulley (AFM GZEs) or the later high-comp, MAP gzes have a 120mm pulley.

Its fairly easy to put the 120mm SC12 pulley onto the SC14, I did this actually for better chassis rail clearance in my AW11 (more boost is an extra bonus!) as the SC14's standard pulley sticks out about 10mm further.

Cheers, Nick

[Cameron_Datto]

i made 13.5 psi on the stock pulley ratio of a Sc 12 with the sc14 supercharger fitted , your air temps get to hot at idle after 10 minutes idling without ABV , i was getting to 100 deg inlet temp , So i refitted the factory " ABV " But in opposite direction of air flow throught the valve ,This stopped ABV bleeding off boost pressure around 13spi and dropped the inlet temps to a Max of 50 to 60 deg after 10 minutes of running at idle speed .

[mic*]

Nic,

Tonight i welded the pulley up coz it was slipping. The funny thing is, i know it hadnt been until a point where i lost boost, this is proven by marks i made on the pulley. After welding it, went for a spin before, and got up to 16psi. Bit strange but

Problem now is that my water injection was hobbs switched at 10psi which comes on at such low revs that i drown it, so until i fix that its mega hot and more fuel hungry...

[mic*]

i made 13.5 psi on the stock pulley ratio of a Sc 12 with the sc14 supercharger fitted , your air temps get to hot at idle after 10 minutes idling without ABV , i was getting to 100 deg inlet temp , So i refitted the factory " ABV " But in opposite direction of air flow throught the valve ,This stopped ABV bleeding off boost pressure around 13spi and dropped the inlet temps to a Max of 50 to 60 deg after 10 minutes of running at idle speed .

I have the ABV blocked at the moment too which is also giving me more heat. But it bleeds boost until the ECU kicks in the clutch that isnt there anymore... And then again up top to prevent "overboost" - ghey...

I would still really like an idle bypass tho... even say switched at ~ -10...

Your charger is pre TB tho isn it? Whereas mine is post. I dunno if it still gets that hot spinning in vacuum? I kinda guessed that if there are limited air molecules to carry away the same amount of frictional heat...

[nick.parker]

Roughly i'd guess dont spin it any harder than 15,000rpm.

Thats way too high. Set a limit of around 9 - 10,000rpm and don't exceed it. Around this area is where you start risking damage to the 'cast on teflon' rotor coating. And due to the thickness of the cast on teflon, you cannot get the rotors re coated (you'd need a cast to put them in) as the coating is 500microns (0.5mm thick) most coating places do 50 microns. Also you really should retain a vacuum (idle) bypass valve to keep cruise (light load vacuum) temps under control.
I have seen failed SC's in a few 4AGZE with SC12's and big pullies driven really hard.
At one point I used the SC14 and a 168mm / 120mm pulley combo (giving 9800 sc rpm at 7000 engine rpm) this netted 18-19psi and shitloads of torque.Why would you try and run any higher than that with old technology! I ran it for 6 months with no problems. But something unrelated caused my crank pulley to crack, so I'm using the stock one for the time being, still with nice performance, and noticibly less SC whine ;-). I didn't thrash the engine all the time nor did I often rev above 6K - except for a few occasions when I tried some Wade 267 cams and it was happier at higher revs...the cams didn't suit the torquey nature of the car..but there are more suitable cams than the stock ones out there, that wont weaken the low end so much to get some top end gain.

Info on my setup is here: http://www.e-wire.net.au/~nrparker/M...new_engine.htm

Cheers, Nick.

[rick q]

A couple of you have noted that intake air temps rise significantly after long periods of idling when the ABV is removed or blocked off.

Why does the temperature rise?

[nick.parker]

Hi,

I don't yet know the physics behind why the heat is generated. The only job I imagine the bypass does is equalise pressure across the SC. And this somehow makes a big difference. It takes a while to heat the thermal mass of the charger, intercooler etc when sitting still (i.e. no cooling air stopping heatsoak except convection from the hot block etc)

On a similar note, I recommend clutching the Toyota SCs. When I played with running the SC all the time, I discovered it creates a fair bit of heat even when the resulting manifold is below atmospheric (i.e. vaccuum) and heated my water to air ICs water a lot when driving slow.

Cheers, Nick

[TRAV-KE55]

Whats the most output someone has had on a 2lt engine and at what revs, i want to try to get 170rwkw

[nick.parker]

While it might be possible, I estimate (based on my cars output) that 170-180 engine kW is about the most you could squeeze at the limit out of an SC14, using a 10K max SC speed.

[brett_celicacoupe]

i hope to make a twincharge setup using a SC14 soon. if the SC was programmed to switch off at an absolute max rpm of 3.5k, how high of a ratio could you run the SC to the engine before the belt will slip under accel etc? i also will be running it through a large IC so this should lower intake temps a lot.

and what sort of boost would this setup produce if the SC rpm was limited to 10krpm.

thanks for teh help in advanvce

brett

[nick.parker]

The belt doesn't slip from accel, rather from the amount of torque the SC needs, which goes up lots at higher RPM (SC inefficient). Practically every week I needed to tension the SC belt at 18psi boost on my 4AGZE. But some of this was traced to flawed oversized SC pulley, the guy that made it f#ked up the mahcing of the 5PK ribs, even though it looked ok at a glance...... But the slip occurred above 6- 6.5K rpm usually. With 12psi boost at the moment I never have belt slip at high rpm, and haven't tensioned the drive belt for months.

NOTE : I don't have an engine driven mechanical water pump on my block (went electric) so the SC belt is ONLY for the SC meaning I get better 'belt contact' on the crank and SC pulleys than a stock vehicle. A guy I know had belt slip problems with the std water pump sharing the belt too, at 15psi on an SC14.

In answer to your question, If you had a 2L (1G-GTE) a rough ballpark figure could be :-
10,000/3500 = 2.86 ratio. Engine need 1L per rev for 0 boost, but SC supplies 1420cc * 2.86 = 4.06L, say SC leakage (dependant of rpm/boost) is 20%, then approx 4.06 * 0.8 = 3.2L approx, into a 1L space would give 2.2bar boost, or 32psi. This is just a hack calculation and theres no way I'd try for that much boost...should get you started though.

Cheers, Nick.

[brett_celicacoupe]

ill probly only be aiming for 15psi max from idle => ~3500rpm, then something like 25psi from there onwards

thanks for the reply

rep for you

[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?

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