Bought a Paxton Superchager for 3.2, what to expect and how to improve?

[Ds1]

I just bought a Paxton SN2000 supercharger kit here on the forums and want to be ready to install when it arrives. The kit includes all the major components but no belt, oil lines, charge/intake piping.

It includes a chip and BEGI FPR. I will want to run very conservative boost on my 3.2 (7psi absolute tops). No intercooler came with these kits. Here is a picture if you aren't familiar: http://forums.pelicanparts.com/uploads18/paxton+engine1303260668.jpg

I don't care about making huge power, I just want some kick in my butt and reliability. Since I have to make the charge piping anyway, would it be worth it to try and squeeze in a small intercooler, and maybe a blow off/bypass valve? (It was always intersting to me that these never had a BOV in the kit).

In the picture you see the AFM AFTER the supercharger which seems silly to me (why put it under that extra stress). I can just put it in the front of the SC, right?

I have an old MAF kit laying around too from Autothority - maybe I could use that too? Worried about the fixed air temp sensor though.

I will be running a boost only gauge in the clock location - should I bother with installing an AFR gauge too? If so, can I use the old O2 sensor location or do I need to keep that for my DME to work right?

Lastly, I don't have AC and the system seems to use the AC pully. I have seen other pictures without AC and there is some auxiliary pully installed. Any idea about that?

Give me your input! Should be a fun build.

[Tippy]

I was a Vortech guy, but Paxton created the centrifugal SC AFAIK - so respect goes to them.

I can't express to you how important an IC is. These blowers run cooler than turbos due to like 50-60k RPM impeller speeds, but they still heat the air a lot.

An IC is a win-win. More power and safer. Look on eBay for cheap intercoolers (also cheap aluminum piping and silicone couplers). CXRacing and Treadstone offer very cheap IC's too.

You must use a BOV. Compressor surge is pretty rough as the impeller is driven by the crank. You can pick up these from base kits from guys upgrading to larger, higher end ones for cheap.

You'd need another bung for your WBO2.

[Ds1]

Great response, thanks. I have to try and figure out how the heck to plumb the intercooler but I'll do a CXRacing cheapy.

Any BOV recommendations? I have a Forge dual diaphragm BOV on my turbo Miata but I kinda hate the ricey "tu-tu-tu" sound it makes when the 2nd diaphragm closes. But it is nice that it seals perfectly at idle which would be important for the 911 since I'm running a AFM and not standalone ECU with AIT. Maybe a Bosch recirculating type fed back into the intake?

[Tippy]

No need to feed back boost from BOV, just vent to atmosphere. My 3.2 was using an AFM too with Protomotive chip.

My BOV is an HKS I ran on my Vortech back in the mid-90's. On my Vortech, it sounded like a hurricane when I let off. Now, I run it on my turbo and it sounds like when you disconnect an air hose off an air compressor.

[tobluforu]

If you have an air dam up front with a cut out, you could always run a water/air ic. Yes its a lot of plumbing and not as efficient, but its better than nothing. I would also start with a smaller pulley and shoot for 5 psi max and then move up after you get the hang of it and have it dialed in.

[prschmn]

Boost control with a supercharger is controlled primarily with pulley diameters. But a bypass
setup is well advised-blowers are tough on belts without it. If you're spinning the blower fast enough to make more than you want it's just wasting horsepower doing it.

[Ds1]

I was considering Air/Water but it's complex and HEAVY. Also agree on the 5psi. I will be running the stock clutch for now too so I want to go easy on it.

Tippy, where was your AFM located vs the BOV though? I heard that if the BOV is AFTER the AFM and vents to Atmo then the car will go super rich during shifts and not run right since the air it metered isn't getting into the engine.

[prschmn]

BOV must be after the air flow meter-and not vented to atmo--what you heard is correct

[Ds1]

Ok. I want to put the AFM before the supercharger to help with lonevity, too, since I have to make the charge pipe anyway.

[Tippy]

Originally Posted by tobluforu

If you have an air dam up front with a cut out, you could always run a water/air ic. Yes its a lot of plumbing and not as efficient, but its better than nothing. I would also start with a smaller pulley and shoot for 5 psi max and then move up after you get the hang of it and have it dialed in.

Whoa! Wrong direction. Start with a larger pulley to slow the blower down (blower side that is, not crank).

[Tippy]

Originally Posted by Ds1

I was considering Air/Water but it's complex and HEAVY. Also agree on the 5psi. I will be running the stock clutch for now too so I want to go easy on it.

Tippy, where was your AFM located vs the BOV though? I heard that if the BOV is AFTER the AFM and vents to Atmo then the car will go super rich during shifts and not run right since the air it metered isn't getting into the engine.

My BOV is right after turbo compressor outlet pre-IC and the AFM was after the IC. It never failed from boost like others had stated over the years.

The AFM had boost going through for many years without a hitch.

[911SauCy]

Water/Methanol injection, properly tuned, will blow your mind.

Lowered IAT's, no det, more timing, more power

I tossed an off the shelf kit on a roots style blown Buick I had. Properly tuned, the methanol helped gain another 48whp/54ft lbs, on a car that made 348whp total. Obviously, outcome on the 911 would be different but big gains/piece of mind would be possible

[tobluforu]

Originally Posted by Tippy

Whoa! Wrong direction. Start with a larger pulley to slow the blower down (blower side that is, not crank).

yeah, that's what I meant, whoops.
I only have experience with one blown car, and that was a dodge viper that has a novi 2000 blower on it. So a Porsche setup compared to a viper is apples to oranges, but the basics are the same. I ran an 8 lb pulley towards the end and that car was wicked fast.

[Ds1]

Originally Posted by 911SauCy

I tossed an off the shelf kit on a roots style blown Buick I had.

Do you remember the kit? Was it able to run without electronics, ex. off a boost signal like an FPR?

[angelny911]

chime

[Ds1]

Been reading about meth injection... Very cool, would save me a lot of IC plumbing, but the fact that I have so many failure points (switch break, leaks, electrical failure, forget to add water) is scary. Everyone says 7psi is safe on a non-IC motor anyway, hmmm...

[Tippy]

Originally Posted by tobluforu

yeah, that's what I meant, whoops.
I only have experience with one blown car, and that was a dodge viper that has a novi 2000 blower on it. So a Porsche setup compared to a viper is apples to oranges, but the basics are the same. I ran an 8 lb pulley towards the end and that car was wicked fast.

My friends 06 made 750 hp and over 800 tq with a Procharger IIRC, man that car pulled hard!

[kuehl]

DS1,

I've played around with a blower on my 87 for several years, boost ranging from 3 to 8 psi, pump gas.

Depending upon your ambient air temps coming in, you can get away without
an IC at 5 psi however your do lose HP without. When summer temps get hot you will notice it quickly.

I've run mine with the stock AFM after the blower and 2 bov's in between the blower and the AFM, no issues.

Initially I had a rising rate FPR, however because they can be 'funky' switched over to a fixed higher FPR, larger injectors, along with mods to the DME FI pulse widths and timing maps (thank you Sal).

I'd be cautious over 5 psi on stock engine (long term wise things do get hammered and worn), avoid aftermarket pistons with high tops unless you plan to twin plug and if you do ...better rings; I had my engine in and out twice learning about that.

Be aware of blowing into the crank or oil tank.

A good wide band with a gauge in your face is mandatory; it tells you a lot about what's going on and warns you of things ahead.

Boost gauges, ... it is what it is once you have your ratio's set, but good to know when you are near the top (where things can go wrong fast).

Presently I'm playing (the hard way) with 3.5 jugs and pistons 9.5:1; you can have just as much fun stock.

[Ds1]

Originally Posted by kuehl

Be aware of blowing into the crank or oil tank.

Thanks! Good info. I was thinking 5psi too. FPR should be fine for that low of boost.

But - what do you mean by the above? I know you cut the oil tank return line in the SOK instructions.

[Ds1]

I wonder if 5psi intercooler AND meth'd would make as much power (but safe) as 7-8psi