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Xnke

Positively Displaced

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As soon as the belt is fitted, I'll send the ZX damper off to be rebuilt, and start working on the charge piping, and relocating the coil pack from the passenger's strut tower...it will have to be moved to clear the supercharger. The bracketry will receive some NVH additions, and then I'll start mounting the brackets to the car, making the final adjustments, and figuring out how to get my dual 12" electric fans to clear the belt. One of them looks like it'll be touching the belt, and that will simply not work. I think I can get by with a single 14" electric, or I can go back to the stock fan and hope I have room to clear both the radiator and the crank.

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The problem isn't blade diameter, it's depth off the radiator. I don't have nearly as much room between the radiator and the water pump in an S30 as you do in the ZX, Ernie.

 

Anyway, here's the work from this evening:

 

IMAG0026-1.jpg

 

And the room I have to work with for an airbox:

 

IMAG0027.jpg

Edited by Xnke

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Not sure if it's an option in your case but I have heard of people cutting out the stock rad support and fabricating their own. You might be able to push the radiator a bit farther forward. You also might be able to push the engine back a bit, though that is a bit extreme. Maybe set up a pusher-fan set up? I know it's not ideal but it might be sufficent...

 

Probably stating the obvious and not helping worth a damn but you never know!

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Nah, radiator and core support are staying put. I don't have time to do that kind of structural work on a car I drive every day. The radiator currently has two 12" fans on it, which draw a buttload of current, but I couldn't find a 14" fan that I could work the mounting out on. They were all too thick in the motor housing area.

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Haha makes perfect sense, that'd take quite a bit of work. Have you looked into a mishimoto fan? They seem to be pretty slim. How bad would it be to use a pusher system from the front? Not sure if it would make sense at all, or if it would be better to run the fans sandwiched between the intercooler and radiator or in front of both.

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Pusher fans suck. They really aren't very effecient as far as getting the job done goes...they work, but not well.

 

a proper puller fan, with a shroud, will do a much better job. That, combined with ducting the radiator infront of the core support, and ensuring that all the air coming in the front opening of the car MUST pass through the radiator, will do much more than trying to go to a less effective fan setup.

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Doing some math this morning, and the current drive ratios will land me with a theoretical 9.5lbs of boost.

 

For reference:

 

{[supercharger Displacement/(1/2 engine displacement)]*Drive Ratio*14.7} - 14.7 = Theoretical Boost

 

In this case:

 

{[1.032/1.4]*2.23*14.7} - 14.7 = 9.5lbs

 

Taking into account intercooler drop, which we'll guess at 1-1.5lbs, that should net me 8-8.5lbs, if the super was perfect, and my engine was perfect. Engine is about 80% VE stock, ported head and cams can bring that up to 87-90% for a very well sorted street engine and 95%+ for a race engine.

 

At my current drive ratio, the M62 will be spinning 15,164RPM at a crankshaft 6800RPM. I shouldn't need to go much higher than that, but I'm safe for peak excursions to 18KRPM. (for reference, at 7000RPM, my alternator will be spinning 21,000RPM...)

 

Here's a rough attempt at picking numbers off the compressor map and generating a table: (no, it's not exact...but it's within a few CFM and the efficiencies are within a few tenths)

 

2000 engine RPM, 225 blower cfm, 65% efficient

3000 engine RPM, 335 blower cfm, 66% efficient

4000 engine RPM, 460 blower cfm, 65% efficient

5000 engine RPM, 625 blower cfm, 61% efficient

6000 engine RPM, 710 blower cfm, 57% efficient

7000 engine RPM, 812 blower cfm, 53% efficient

 

2.2CFM is about 1HP, so theoretically the airflow at 7000RPM would support about 370HP. At that blower speed, it will require 36HP right off the top, so cut that back down to 334HP, call it 330HP. This is the absolute maximum crankshaft horsepower possible with this blower in this configuration. 80% of this (pretty well generally accepted for a stock L28, stock cam, with a perfect tune) is 264HP. Factor in 15% for driveline loss, and 224HP would be at the rear wheels. So, a stock 140RWHP engine would be bumped up to 220ish HP with this setup, assuming a perfect tune and a stock cam. We're doing a lot of handwaving here, but most of the numbers are pretty generally accepted and can be worked backward to get pretty dang close to right. For instance, a canadian guy running the same blower at 6PSI, intercooled, on a bone-stock L28, with aftermarket engine management and a dyno tune, produces 255RWHP That's a bit more than I figured with the handwaving, which means I'm just being conservative here. (I am quoting the figures I can find from 280Zedx's build here)

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Your handwaving may be closer than you thought, sadly at the crank though.

 

I just looked up 280Zedx and saw the post where he mentions his car (or engine, not clear in the post) dynoed 225hp and 245 lb*ft torque.

 

IMO/E, a stock 280Z should be at about 140HP at the crank, not wheels. Perfection at 6psi should yield 140 * (6+14.7)/14.7 = 200ish HP at the crank, minus parasitic blower losses plus stuff I didn't calculate.... Note that stock a 280ZXT is 180HP at the crank on similar boost for comparison, but probably on lower compression. That's my version of handwaving!

 

Not trying to dump on your project at all, just saying that pulley juggling may be needed if you have a power goal of 225 at the wheels.

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Guess you haven't dynoed many stock 280zs, have you? Most factory engines in good condition *do* put down those numbers to the wheels. Also, comparatively few dyno sheets that you find here are engine dynos, almost all of them are chassis dynos. Also, the L28et at 180hp is SAE net, not gross (crank hp minus accessories).

 

EDIT:

 

Did some more looking around, it was Z-ya's Camden supercharger that I was thinking of. His setup was not intercooled, as the supercharger was mounted directly to the intake manifold. From October 23, 2006:

 

I have a JCR SC (Camden) on my L28 race car, and so far I've got 255WHP out of it at 8psi. I'm running very conservative timing (20 deg at 8psi).

 

Hear are the details:

 

- F54 flat top block and pistons.

- P79 head (round port 6:1 header)

- 2mm Gasket (8:1 CR)

- Comp Cams 280 dur, 460 lift cam

- Intake and exhaust ports matched

- Camden supercharger and JCR intake manifold

- Megasquirt running Extra code v029

- Ford EDIS-6 ignition module

- 36-1 crank wheel with VR sensor

- Chrysler coil pack (uses GM HEI plug wire connectors)

- Six 370cc/min Ford Thunderbird injectors

- Stock ZX FPR

 

The Camden unit used in the JCR kit is larger displacement, at 112 cubic inches, but is a two-lobe straight-rotor unit that is less efficient overall. Camden's website states that the unit will produce approximately 750CFM at the maximum recommended rotor speed.

Edited by Xnke

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Correct. I have not dynoed any stock 280Z/Xs, but looking around the net saw that 120-130HP was average. At 140 you're in Tony D territory!

 

Regarding stock 280ZXT horsepower, we're saying the same thing.

 

I realize that most dyno sheets out there are from chassis dynos rather than engine dynos, but 280Zedx doesn't mention which.

 

If 280Zedx made 225 at the wheels, would you think that 30whp difference (255-225) is good bang for the buck considering that one is a race engine with a cam and is running 2 more psi on a bigger blower, not to mention no distributor? I don't! There should be a bigger gap between the 2. That's why I am sticking to my guesstimates.

 

All I'm trying to do here is potentially reduce your expectations for 6psi (and, I suppose 8-8.5psi) on a stock engine.

 

PLEASE show me I'm wrong! I'd love to be, because it would mean you're blasting around in a much quicker car than I would have thought. And, after all, isn't that the goal? B)

Edited by bradyzq

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You have to look at the details. 140RWHP is pretty common on a clean, well-sorted stock engine. 280Zedx is running a stock L28, with a stock head and a stock (tiny) cam. And puts down 225HP. I don't have a stock engine in my Z, it's a 2.9L with a mildly ported head (35mm intake ports, heavily worked exhausts, moderate valve unshrouding, and profiled valve guide bosses) and a mild camshaft profile on a 107.5 LSA. Z-ya was running a lightly worked head (port matched, NOT ported, there is a difference of 40+ hours of work there in some cases) with a cam a little smaller than what I currently run in the N/A car. Also, the Camden blower might look bigger as far as displacement goes...but it's a two-lobe, that moves LESS air than the Eaton does, at every RPM in the table, AND has a much lower rev limit. It's limited to peak 13,000RPM, and at that speed moves a maximum of 750CFM. The M62 is rated to 14,000 continuous, 16,000 peak. At 13,000RPM, it's moving just over 800CFM. Also, eventually I'll be stepping up to the TVS1320, which will move 1,320CFM. That will be a year or better, though.

 

The same cam I'm currently running, in what I would call a mildly prepped N/A race engine (similar spec with lower compression and slightly less displacement than what I run on the street every day), with a very similar intake manifold, produced 170RWHP. I have not put my car on the dyno yet, due to low-RPM tuning issues that I believe are related to the brake booster vacuum leak I currently am working on fixing. I will be dynoing the current engine BEFORE the supercharger is installed, to get a good baseline. The current head is a mild port job, and will be used until the new head is finished and installed.

 

The first cam core has been sent off to Isky for the initial regrind, which will be a mild lobe profile with a wider lobe separation. A second cam will be sent out to Dave at Crower Cams to be cut to what he thinks will be a good profile, on a similar lobe separation. I have a five gallon bucket of rocker arms that are about to be sent out to delta camshaft to get reground later this week. (shipping is gonna be a ***** on that...)

Edited by Xnke

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Got the super mounted up yesterday, and everything clears so far. I will DEFINITELY have to figure out a fan, the exisiting setup just isn't going to work. I'd have to move the engine back two inches (doable, but a lot of trouble) or go to a different fan setup (also doable...but not ideal, really.)

 

Intercooler piping will be interesting, the charge pipe will have to come off the super at a 45* angle, then into the intercooler at a 45* angle, then out of the intercooler at about a 15* angle into the manifold.

 

Went to the parts yard today, so i'm broke as **** for a little while. Have to cover the current bills, get back on top of things, and get the silicone ordered for the charge piping, have to hunt down two more of the DSM 450cc/min blue top injectors, and order a stack of manifold gaskets...the fel-pro gaskets are just getting worse and worse.

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Waiting on material to show up now, it'll arrive thursday. The new intake manifold will be a junkyard sheetmetal version of Monzter's spectacular CNC machined ITB madness, using runners that will be 10.5" from the cylinder head face to the end of the velocity stack, 1.5" ID, and angled up about 14* from perpendicular to the cylinder head face. It's going to be a tight fit, obviously, but it WILL fit in an S30, and a single-throttle version will be fitted to an S130 for a turbocharged application.

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Hi Xnke,

 

I'm following this thread with great interest. What you've done so far looks great and has given me some ideas on my current build. I'm currently trying to figure out how I'm going to run a serpentine belt on my setup. After seeing how you have set up your pulley/tensioner I think I'm going to route mine similar to you. I've never seen a sliding tensioner like your doing. How does it work? All the tensioners I've seen swing in an arch.

 

My build is a little different, but there is a lot of similarities. The biggest difference is I'm using a rotrex c81 supercharger, but locating it in almost the same position you are. I bought a BHJ damper that has an 8-rib pulley attached to it instead of the v-belt pulley. I'm using an 8-rib alternator so I can line all the assessories up. I think this will give me a little space to the radiator and fans.

 

On your posts about estimating the horsepower your set up will make, my best guess is that you are being conservative. Corky Bell wrote a great book called "Supercharged! Design, Testing and Installation of Supercharger Systems". When I was planning my supercharger build I created a spreadsheet that used all the relavent equations from his book. I followed his workflow on designing my supercharger system in how it was applicable to what I was trying to achieve. There's a lot of good advice in his book, especially on avoiding detonation, which was my biggest concern. I'm not expecting my actual power numbers to come out exactly as calculated, but it at least was something to use that wasn't a blind guess and should get me in the ballpark. If you want the spreadsheet to play around with I'd be glad to send it to you.

 

Keep up the excellent work. I'm looking forward to watching this build and seeing the final outcome too.

 

Rob

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I looked at a serpentine belt configuration, but how are you planning to run the water pump? It won't work the same as it would on a conventional serpentine setup, since MOST of the ones I'm familiar with wrap rib side on the crank and flat side back around the water pump. I am running A/C also, so it wasn't going to work for me.

 

Anyway, this project is far from dead...just haven't been updating it here due to work on the manifold, which is down in the fabrication section.

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I just read through your intake manifold thread too.  You are a very good and resourceful fabricator.  Was that a fire extinguisher you used for the plenum?  I just bought a custom intake that was very similar to what I wanted.  If I had your welding talents I would have tried to make one too.

 

It's pretty cool someone else is doing a very similar build at the same time.  Different types of superchargers, but a lot of similarities. I think yours will be more torque oriented and my will build power at the higher rpms. 

 

This is the spreadsheet I used to figure out what blower and pulley sizes I needed.  I'm pretty sure this would work for yours too, just some of the variable values are different.

 

post-11209-0-72407100-1354753538_thumb.png

 

https://docs.google.com/spreadsheet/ccc?key=0AsePDCmbU5HudGhDSG5HYUtBbk5CVUtkNTl3RTdmc2c

 

post-11209-0-39263800-1354754102_thumb.jpg

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Keep in mind the actual locations of the parts...your alternator is drawn quite high on the block. You need to ensure you have at least 50% belt wrap around the crank pulley, and shoot for no less than 30% on your accessories. Also, serpentine belts are designed to be run at a VERY specific belt tension, or they WILL slip. The only reason I'm using a manual tensioner assembly is that I already check my belt tensions every week, and it was quicker to package. I would seriously consider a spring-loaded tensioner assembly. If you are using an serpentine belt, then the tension should be at a minimum 25lbs*8ribs=200lbs. Consider this when you build your tensioner and idler setups.

 

And yes, actually...that is two fire extinguishers that got welded together for the main plenum.

Edited by Xnke

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Ya serpentine's need a lot of pressure.  The belt tensioner on my mini cooper s (supercharged model) is quite hefty.  I put a smaller pulley on my charger and needed about a 4 foot bar and some heft to get it un-tensioned.  Would be interesting for someone to do a full serpentine conversion.  Seems like a lot of work for little gain to me, but hey, what do I know?  Is it possible to weld onto a dampened pulley? I have a powerforce crank pulley on my L28 and it only has 2 threaded holes on the outside... any way of attaching a serpentine pulley on the outside like you've done with the stock pulley?

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You shouldn't weld on something like that unless you know exactly what it's made out of. Call Powerforce and ask, would be my thought.

 

I had the tape on the car last night, getting an idea of what has to move where to get the drive belt on. The radiator needs to move 1/2" forward, or I need a thinner fan than the Hayden Trans-Kool that's on the car now. If the core support was flat, instead of having those 1/2" raised panels that the radiator mounts to, then I'd have just enough clearance, I think.

 

The radiator is a 240Z 3 row copper unit. I am pondering moving to a 280Z (taller) aluminum 2-row (thinner) radiator.

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