Zsane

This condition, or are other cars differant?

I'd like to hear opinions about this condition! Anyone care to elaborate their thoughts?

Lowering the car lowers the center of gravity, good! leaving the control arm pivot points in the stock location also lowers the roll center, a measured point, one line running 90 degrees from the top of the struts, intersecting with a line from the ball joint pivot through the control arm pivot, and the last running from the centerline of the tire to the two first lines intersection, where this last line crosses the vehicles vertical centerline is the roll center. To get more stability the point of the center of gravity and the roll center should be moved closer together, by lowering the car and leaving the control arm pivots alone, or not using bump steer spacers, this relationship remains the same but lower, by using the bump steer spacers, or raising the control arm pivot points, or both, the center of gravity is still lowered but the roll center is raised or brought closer to the center of gravity point. Think of the roll center as the center pivot point of the car as viewed from the front, side to side, and the center of gravity is the weight on the end of a rod, the distance between these two points is the rods length, or leverage, the shorter the distance the less leverage the weight of the vehicle has to induce roll! You need to lower the center of gravity to the roll center, not the ground, and if the roll center moves down with the center of gravity, the leverage remains the same. Good suspension geometry also reduces the movement of the roll center as the suspension goes through rebound and compression. You’ll have to take lots of measurements and make drawings to scale to map your set up on paper, make changes and see where things go. The exact center of gravity will be a bit more complicated to come up with. Have fun!

Ok, I made the calculations for blower size, boost, and supercharger rpm's and pulley sizes for an L28 using the math in the book "SUPERCHARGED! Design, Testing and Installation of Supercharger Systems" by Corky Bell and this is what I came up with. An 168ci L28 with 170 HP @ 5600 rpm has an airflow value of 217.78 cfm to support 350 HP you'll need airflow of 433.67 cfm, and a pressure ratio of 2.06 which comes to 15.56 psi boost. An Eaton M60 displaces 60ci per rev. and would have to turn 12,490 rpm to achieve this, this is close to the max of it's operating range but not above. With a 2.5" diameter blower pulley, the drive pulley would need to be 5.58" in diameter. Using an Eaton M90, the blower speed would need to be 8326 rpm, well below the max operating speed, with the same 2.5" blower pulley, the drive pulley would have to be 3.72". The M90 blower at it's max could flow 625 cfm at a pressure ratio of 2.94, and a blower speed of 12,016rpm, still less than the M60, boost would be 28.54 psi and a theoretical HP rating of 500hp. drive pulley would need to be 5.36" in diameter. and of course more fuel would be needed for all applications just as with a Turbo setup, and intercooling as well. So the Eaton blowers could put out some power on a Z car if set up correctly, I have a stock 77/ 280z sitting here that we never drive and I think this would be a great test mule for just a project, blower can sit on the passenger side and run through the intercooler in front of the radiator and back into the intake manifold, throttle body will be with the blower unit on the passenger side. Now to start gathering parts, low boost to start and more if that goes well.

The old syle roots blowers create lots of heat, most of them ran the carburation through the blower which cooled the unit and the charge a bit, they are not very efficient, the Eatons are a roots type, but the rotors are twisted and are much more efficient, should be used with the throttle body upstream of the unit with FI injectors downstream, an M90 displaces 90ci per rev and the M60 60ci and the M45 45ci, the cool part is setting up a bypass so the blower can be turned on or off, the M45 on the Mercedes SLK has a clutch like an AC unit. The Eatons will give good bottom end where the ATI Prochargers or Vortec units will give better top end boost, the Eaton runs cooler than the old style roots type but with a smaller pulley and higher boost would work fine with an intercooler, as will the centrifugal units. The screw type are compessors so should be sized for application like a turbo, the Autorotor screw type are very efficient and actually create most of thier heat at idle instead of in boost, Kenne Bell and Whipple use this configuration, cost is high but coming down, the Mazda Mellinia unit is a screw type and could work as well. Supercharging is the way of the future as can be seen by their increasing application in the industry, higher efficientcy than in the past, bypassing for economy or power, and streetability from good low end boost. We need to jump on this trend and see what we can do.

Don't cut away from the short side, build it up if you mess with it at all, this has to do with equal flow around the head of the valve, a straight port ninety degrees of the valve head will promote even flow around the diameter of the valve and increase flow, once it gets past the valve it will make the turn and exit just fine, the valve is the obstruction you need to deal with. Cutting away at the short side promoted uneven flow around the valve head and will reduce overall flow numbers. I know many may disagree but I feel strong about this from my initial testing and can't wait to proove this on the bench. Anyone with a die grinder can cut away at thier ports, but not everyone can grab the tig and build up areas inside there, I'm talking about reshaping not reducing ports, just don't mess with the short side radius.

I have a bunch of photo's to post, I will be scanning them and posting soon, these old mags are great!

At this point it looks like I'll be using two large structural aluminum angles, there are some 3" x 6" x 3/8" chunks at work I can use, very strong stuff T6 used for anchoring custom commercial window frames to high rise buildings, I work for a large Architectural Glaizing contractor so we have lots of large steel and aluminum items as these laying around, as well as the machinery to fabricate it. I'm planning to bolt one angle to each side with the returns facing each other under the diff, both legs will have to be shortened and then I was planning to bolt a flat bar under the angles to tie the two sides together. The front mount will bolt through the plate and angles, another set of angles or a piece of tube could be incorporated between the vertical legs of the angles to act as a safty loop, that would be easy, first things first. The vertical mounting location of the angles will be critical to ensure that the axle flanges and driveshaft flange are in the proper locations or optimum locations. I was thinking of using slots rather than holes for mock up so there will be adjustment available to get the geometry correct, and once the proper locations are determined a final set will be fabricated using holes so that the position of the diff cannot shift. As far as axles are concerned I will find a set off another Supra along with the stub axles and go from there, I will remove the axle flanges from the diff first to see if any possible swaps with those can be done. Right now I want to make sure I can mount the thing in the car, one step at a time, but I will move forward as quickly as possible and post my progress. I was planning on having an access hole or slot in the bottom of the mount directly under the driveshaft flange to aid in installation and removal of the bolts. I understand the need to lift the drive shaft up to the flange after it is slid into the trans. It could be changed to a top mount config. but the fact is that the driveshaft will pass over the front diff crossmember and swaybar in any configuration. Hopefully there will be room to slide the shaft above the diff and then forward into the trans, but I can't tell until the diff is mounted into the car, if room doesn't permit this, it may be possible to unbolt the diff from the mount and lift the nose out of the way for shaft installation. I could mount the angles so the return legs face away from each other and bolt directly to the front diff crossmember, but the crossmember will still have to be dropped for install this way, unless the center is cut out and you have the rear mounted sway bar. Either way I'll make it work.

My scanner is on the blink so I just took a picture of the picture, it could be a bit distorted, I have more pictures of that car but I want to get them scanned so they're accurate and then I'll post them. The picture is much larger, but I had to reduce it to post.

This is from an original Bob Sharp Racing catalog add (1978), note that the rear quarters have dzus fasteners attaching them to body. Nice Look! Check that rear wheel.

This is from a 1978 Camel GT Monterey Triple Crown program guide. If anyone wants a larger version I can email it to you, lots of other great photos in this thing as well.

Well here's the general plan for the front, either 1/4" steel or 3/8" T6 aluminum, one u-channel or two angles and a flat bar, will need an access hole below the flange to get to the bolts, may put some slots here and there for weight purposes and a strut running from front to back underneath u-channel, rear mount will be another angle bolted to the top in place of that stock Supra mount, above the diff cover extending past the cover and hanging down to the bar.

Sorry guy's, but you can't compare the best setup Z suspension with any modern Formula One or IRL setup. Yes those IRS systems are the best in the world, the letters IRS is where the comparison ends. Accuracy and consistency is where it's at in a suspension, even with your geometry correct on all accounts, without a torsionally ridged chassis the geometry goes right out the window with any flex, and bushings, do you have any in your setup? Well there goes your geometry as soon as you put a real load on it. I know, you car out handles anything on the road! it's all relative, see what it does behind a car built for handling. Just like a kid screaming about how fast his buddies 5.0 or Camaro is, then he goes to the drag races and after the Top Fuel cars run, the car looks like his granny is pushing it down the track with her walker. He then remembers that is was fast as hell pulling away from that housewives Volvo the other day, Hummm! The IRS advantage: smoother ride over rough pavement, if set up properly, reduction in unsprung weight allows the tires to follow the surface better! Disadvantages: a more complex system that bottom line cost more to setup properly, most production designs compromise optimum geometry and deflection characteristics for cost, the major disadvantage is the ability to put power to the ground, minimal anti squat! High powered cars without rear weight bias (like a Hybrid Z) will have PROBLEMS getting optimum performance and handling. Note the word, problems, I didn't say , it can't be done. The bottom line is both can work great or bad, it just depends on the setup, and on another note, MacPherson strut setups were originally created for cost and simplicity reasons not performance. Except where required by race sanctioning bodies in production-based classes, you don't find them on many race cars do you? With that said, I still love my Z!

Sounds good, 6" rods? stainless hollow stem valves? titanium retainers?

I was thinking about messing with a supercharger setup for an L28 too. I helped build a supercharged Harley and it works great, gobbs of low end torque. If you set it up right you can run a clutch on the supercharger and a bypass, then you can have power and economy, the Mercedes SLK runs this setup with an Eaton M45, that displaces 45ci per revolution, the T-Bird Eaton M90 would work well on a L28, made for a 3.8 liter and fairly efficient heat wise, can be intercooled as well, there are several length snouts available as well. all these pipe dreams, no money, no time, just started a fat job so it's almost time to play ball. This site got me going while I was out of work, check out the archives, some insane discussions, way out there. http://www.theoldone.com/

Check here. http://www.bgsoflex.com/megasquirt.html

oop's, sorry for getting mixed up! wrong model

Backfiring through the carb is a lean condition, check for vac. leaks, fire it up and spray carb cleaner anywhere it could be leaking, throttle shafts included, be carful with the carb cleaner on a hot exhaust, if you have a leak, the idle will jump right up when you hit it with th e carb cleaner, I've heard propane will do the same thing, but I never tried it, I always use carb cleaner, never fails!

Am I seeing this right? An R200 with R180 Flanges, and mustache bar? If so, is this common?

Just picked this up at my local Pic-N-Pull for $50. I'll see if I can make it work. Out of a 1987 Supra, 7.5" carrier with 4.10 gears. Any comments?

http://www.linfoot.net/

http://overboost.com/pix.asp?image=./images/214/full/DSCN3588.jpg http://overboost.com/pix.asp?image=./images/214/full/DSCN3589.jpg http://overboost.com/pix.asp?image=./images/214/full/DSCN3591.jpg

You guy's win, a chopping I shall go!

I plugged #'s into my desktop dyno and this is what I got. 400ci, 10:1 comp w/performance heads 2.02 int/1.65 exh, single plane intake, 850 carb, solid roller lifters, .700 lift 298int./ 302 exh duration cam, large tube headers w/mufflers: 498hp @ 6500rpm 468ft.lbs torque @ 4500rpm same accessories as above 327ci 489hp @ 7000rpm 409ft.lbs torque @ 5500rpm I say 327ci with rear end gearing 2.89 or 3.02 mabe higher if you still can't put the power down without spinning too much, and much slower piston speeds with the 327ci. Stock combo's at http://victorylibrary.com/mopar/m-table-c.htm

torque x rpms divided by 5252 gives you hp right? so 100 ft.lbs at 5000 rpm = 95hp sound right! 850 at 2800rpm = 453hp 810 at 5200rpm = 802hp don't want to be negative, but. lets go the other way. hp x 5252 divided by rpm = torque so 224hp x 5252 = 1176448 divided by 5200 rpm = 226 ft.lbs hp sound right, torque has to be wrong.