New to Supercharges, have SN2000 & have some questions

[ed1le]

Picked up the Iroc in my signature last weekend and have some questions about the combo, boost potential, power potential, etc. Car runs, seems tight but had either an intake leak or headgasket (prior owner had intake off and after re-installing discovered coolant in oil). Regardless, yanking the engine to freshen since there's coolant in the oil. I've read that the SN2000 maxes out around 8lbs of boost. My set up has a procharger intercooler so wondering if that would help increase the boost any? Also, engine has Comp Cams C305 cam w/ 1.6 roller rockers; would I be better off w/ a blower cam of some sort? As a wicked idle, just curious if there might be a better matched cam that could help make more power. The other question is, what's the power potential of this combo currently? ZZ4 block w/ forged rotating assembly, compression is 9.2, there is some port work done to the heads on the intake side (have intake off already), has 30# injectors, 58mm TB, 1-3/4 SLP headers, etc. Lastly, there's an NEX 125hp wet nitrous setup on it. Claims to have never been sprayed but curious what concerns, if any, there might be w/ nitrous & boost. Contemplating just selling the kit but not sure.

[Michael]

Hi and welcome to SCH.

Congratulations on your new purchase. On paper, it looks like one heck of a ride... prior to the coolant leak that is.

I'll try to answer at least some of your questions.

To say an SN2000 maxes out at 8psi boost is very misleading. The maximum boost of any centrifugal supercharger is based just as much it's design (impeller and scroll profile, volute diameter, intended RPM, flow-rate, etc...) as what it's bolted to. An engine that has a relatively low flow rate might see 8psi-9psi boost from an SN2000. Conversely, an engine with a relatively high flow rate might see only 4psi-5psi from the same SN2000. I can tell you that an SN2000 on a stock ZZ4 engine with a TPI fuel system will see 6psi-6.5psi (assuming the blower is spun at it's optimum RPM). However, in the case of your engine, you've not only got a TPiS Miniram intake, but higher flowing (and ported) heads. This will affect how much boost you'll get from the blower. How much? I don't think it would be unreasonable to expect to see between 5psi-5.5psi. But that's just a guess... neither of us will know until you bolt everything back together and see for yourself.

On the subject of the ProCharger intercooler and whether it helps to produce more boost, I'd have to say probably not. This topic has been discussed on the forum here several times over the last while, and the general consensus is that at boost levels below 10psi, physical intercoolers (whether they be air-to-air or water-to-air) actually cause a drop in overall boost pressure. The reason for this is due largely to the added volume the supercharger has to fill introduced by all the additional piping and plumbing along with the heat exchanger itself. In the case of your SN2000, even if it were producing 8psi, the intercooler might prove to be more of a hinderance than a benefit.

In regards to the cam, this becomes a bit of a judgement call on your part. The beauty of these old SN-series superchargers is that they are a nice "accent" to the power you're already producing. In other words, even if the engine was never built for a blower, bolting a Paxton SN series blower to it serves to nicely heighten the power output without any serious engine modifications needed after the fact. So if the cam in the engine wasn't a "blower" cam, it was OK; the power increase was substantial enough to out weight the less-than-ideal cam. However, for optimum power production, it's best to get a blower cam. Of course, this isn't as easy as just calling Crane or Comp Cams and ordering an off-the-shelf cam. Ideally, you'll want to know vitals like flow numbers of the intake and heads before calling the cam supplier. With all the information they'll need, they should be able to make an informed recommendation of the cam you should install.

Using nitrous with boost is becoming much more common place nowadays. The nitrous acts as a gaseous intercooler for the hot air coming from the supercharger's discharge outlet. There's a good set of articles on gaseous intercooling on the forum here, under the Intercooling / Aftercooling section of the site.

Unfortunately I wouldn't want to harbor a guess as to who much power the engine you're outlined will make, as there are an incredible number of factors which can effect that. I don't think it would be outrageous to say the engine combo as you've listed it, would see upwards of 400bhp, but that's just a guess which could be way off.

I hope that helps somewhat.

[antoine]

I would just redo the headgaskets and leave the cam in the car but install 42 pound injectors and get it tuned to be safe. Your camaro sound like what I have now I have a 1988 iroc

[ed1le]

Thanks for the repsonses.

Antoine - after some thought I've decided to keep the cam since I know it all worked well together before I took it apart. I can get it back together & fine tune it from there.

Michael - So if I understand correctly, the better flowing the engine, the less boost the SC will make? I assume this is b/c there isn't as much time for the boost to build vs. a more restricted engine (such as stock intake, heads, etc)? If I switched pulley sizes, could I increase boost that way?
Also, it sounds like I might benefit from removing or at least disconnecting the intercooler for now. I guess I can play with it and see how it feels but what you're saying makes total sense. I never really gave these things much thought but understand how more volume could decrease the amount of pressure.
As for the nitrous, it's a 125 shot right before the throttlebody so does that still help cool the intake charge?

Lastly, any recommendations on replacement head gaskets? If cylinders look good, I may not even pull out the pistons, just mic & replace the bearings after having crank polished (if all looks good). Thoughts? Thanks!

[Michael]

So if I understand correctly, the better flowing the engine, the less boost the SC will make? I assume this is b/c there isn't as much time for the boost to build vs. a more restricted engine (such as stock intake, heads, etc)?

In a nutshell, yes you're correct.

If I switched pulley sizes, could I increase boost that way?

Yes, this is possible, but up to the maximum intended RPM of the blower, which is about 39,000 rpm. You can spin it faster, but any more than about 41,000 rpm and all you'll be producing is more heat.

It's important to remember that these ball-drive superchargers are an old design. Volute and impeller design has come on in leaps and bounds compared to these old units, which are heavily limited as to how much flow and boost they can produce. the only really effective way to increase the boost from these old ball-drives is go with a VR-4 kit and upgrade the impeller and scroll cover. This will effectively double the flow rate (CFM) and boost.

And as I'm sure you're going to ask, "So where can I get a VR-4?", there are two sources: look for a used unit/kit through the usual sources (eBay, Craigslist, SCH classified section, etc...) or call Paradise Wheels and get your name on the waiting list for one.

As for the nitrous, it's a 125 shot right before the throttlebody so does that still help cool the intake charge?

Yes, absolutely.

Lastly, any recommendations on replacement head gaskets?

When I replaced the head gaskets on my Corvette's L98 engine (which is almost identical to a ZZ4 crate engine) I went with a set of Felpro 1010 gaskets. After a lot of research and discussions, they were considered "the best" option. They aren't cheap (about $50 each) but I haven't had a problem with them.

You could also consider a set of Cometic MLS head gaskets. These weren't available when I replaced the head gaskets on my car, but I know a lot of people swear by them. If you're planning to run a lot of boost one day, you might want to consider them.

I hope that helps.

[antoine]

Felpro 1010 is what I have on my camaro l98 with afr

[Blown5.9ZJ]

Go with the Felpro 1010, I use the 1080 (same style, just for mopars) in my Jeep with no problems.

[ed1le]

Got my Felpro 1010's. Waiting to pull the short block out to freshen up due to the coolant contamination. Heads passed the pressure test, however, there was some detenation damage around the combustion chamber of cyl 8 and they're going to have to weld in the pitting and then mill both heads. Waiting on a cost. Guess I'll be selling the N2O kit to fund the head repairs but don't really think it's necessary anyway.

[ed1le]

Also just got on the list for the next run of VR4's that is supposed to happen sometime after the new year.

[antoine]

With a vr-4 42 pounders are a must

Also just got on the list for the next run of VR4's that is supposed to happen sometime after the new year.

[ed1le]

I plan to upgrade the injectors and probably add a blow-off valve as well. First, I want to get it back together and sorted out as is right now and then do the upgrade. I just want to get on the list and have the VR4 so when I'm ready to upgrade, I'll already have it. Car needs some other stuff sorted out though and a good tune.
I was able to get in touch with the guy who originally built the car (he sold it to the guy I bought it from a year ago who, I think, sprayed it & popped a head gasket) and learned a lot about the car. It ran consistent 12.6's at 109 he said and he bought the spray to get into the 11's. However, while playing w/ the spray, blew a head gasket. He fixed it and then didn't mess with the spray anymore and sold the car. I'm guessing the guy I bought it from did the same thing. Anyway, doing a lot of research, the car should be running low 12's without the supercharger based on the current combo and that the cc305 is one of the better cams for a supercharged miniram'd (Stealth rammed or LT1 for that matter) engine like mine. Also, knowing it has an off the shelf TPIS chip in it, I think a nice custom burnt one would make a huge difference. There was also an issue he said with it running rough & performing poorly when it went into closed loop mode so there's an issue I need to work out there. So, I have plenty to keep busy for the time being.

[antoine]

Tpis chips are no good I had one paid 500 for level 5 chip I sent it back for a refund.

[ed1le]

This is a level 6 and obviously not worth squat either.

What exactly is your setup?

[antoine]

1988 camaro iroc 5.7 .030 over ,afr eliminator 195 75cc,svo 42 pounders,tpis big mouth intake and runners,58 mm throttlebody,hooker shortys,borla exhaust,speed pro piston Lf-2256,sn-93 old one now sn-2000, 700 r-4 built by me with a continental 10 inch non lockup 2400 rpm stall,3.42 gears and chip done by mark

[ed1le]

sounds like a nice set up. Do you post over on thirdgen.org? Who is Mark?