Positively Displaced

[Leon]

Haha that was a ninja post on my way to school, but looks like i was on the right line but got the induction system mixed up... Has anyone on here seen a Z with a rear-mounted supercharger or turbo system? Seems like there isn't really enough room for a supercharger system but a turbo system is possible with the use of a fuel cell under the rear hatch. I know I've seen a v8 Z with an alternator run off the driveshaft, seems like you could do a similar system with a supercharger, no?

Why drive a supercharger from the driveshaft, when it can be driven off of the crank? There are losses between crank and driveshaft which means there is less power available to drive the SC. Similar issues exist with remote mounted turbos, there is less heat and pressure available to spin the turbine than there would be if it were mounted right next to the engine. Sure, it'll work, but other than to be "cool" and "different" I don't see a reason to do so.

[luseboy]

Why drive a supercharger from the driveshaft, when it can be driven off of the crank? There are losses between crank and driveshaft which means there is less power available to drive the SC. Similar issues exist with remote mounted turbos, there is less heat and pressure available to spin the turbine than there would be if it were mounted right next to the engine. Sure, it'll work, but other than to be "cool" and "different" I don't see a reason to do so.

 

Haha i was merely wondering from a cool factor standpoint. I would be mounting mine in the engine bay

[Xnke]

Let's try to keep this thread focused on the right side engine bay mount, instead of cluttering it up with other mount locations or turbo/twincharging. I will be updating this thread with the progress, until it becomes difficult to follow.

 

That said, I gave been in contact with several cam grinders, unfortunately only one has been very helpful. have tried several times to get in touch with Ron at Isky after the initial request for a supercharger specific recommendation, with no response as of yet. Dave at Crower Cams and I had a longish chat on the datsun valvetrain and cam development, trying to work out what lobe profiles we can fit on the stick and keep the wipe pattern in place. I will be sending in a cam core for him to measure and a few followers to work with, along with some photos and drawings of the valvetrain.

 

I have an N42 head on the car now, with dished pistons installed. I will be prepping a P90 head for use at a later date, but that will come later this winter.

 

More photos this evening, progress on the intercooler has been good.

[Xnke]

Been working on the tensioner assembly tonight. Had to put a LOT of thought into this one! Waiting on welds to cool off before I start making the rest of the bracketry.

 

EDIT: The photos finally got hosted!

 

This is the hard way to make this panel...but it worked fine.

 

 

One more panel like that and the intercooler is complete and ready to fit into the car.

 

Started on the tensioner assembly. I took apart a stock A/C tensioner to see how it worked, then built a larger, stronger copy. The proper belt tension for a six rib belt is 180lbs working tension, and for a new belt, 210lbs for a few minutes of running, before retensioning to 180lbs. This means that the idler pulley needs to hold 210lbs PLUS 40HP of drive power from the crank!

 

Here's the sliding post assembly:

 

 

The sliding post assembly is cut from 1045 carbon steel, then quenched and tempered to approximately the same specification as a grade 8 fastener.

 

Tensioner bracket bolted to the engine

 

 

And all the pulleys in place:

 

 

Hoping to have enough of the work done to get a tentative belt size (it's looking like a 51" belt will be the right length) this weekend.

Edited October 26, 2012 by Xnke

[Xnke]

too tired to post a real update...will edit later. The 51" belt is too short...a 54 or 55" belt will be the correct size.

 

 

[Xnke]

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.

[redzedturbo]

you will be fine with a 14'' jake i think thats whats going on mine in the near future ie TAX TIME....

[Xnke]

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:

 

 

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

 

Edited October 29, 2012 by Xnke

[luseboy]

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!

[Xnke]

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.

[luseboy]

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.

[Xnke]

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.

[SleeperZ]

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

 

Technically, they don't suck, they blow.

[Xnke]

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)

[bradyzq]

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.

[Xnke]

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 October 30, 2012 by Xnke

[bradyzq]

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?

Edited October 31, 2012 by bradyzq

[Xnke]

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 November 1, 2012 by Xnke

[Xnke]

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.

[redzedturbo]

Jake i say we make a die to cut them out of dead soft aluminum and call it a day. If i blow another gasket on the #6 exhaust port im going to blow a gasket in my mind.