pparaska

Yes, I've heard/read this for years - a smaller engine with the same cam will be more radical. I wonder how much of this is really just based on the stroke and the usual large rod/stroke ratio. Past threads on this board and chevytalk refer to sites the go into an engine's stroke, rod length, intake valve closing point and dynamic pressure. I have a spreadsheet on my site that does this calculation : http://members.home.net/pparaska/VvsP.xls I got the equations from: http://victorylibrary.com/mopar/cam-tech-c.htm Other than differing rod/stroke ratio and stroke between two engines, I don't know of any other parameter that would make one engine see a cam as "larger" (more radical) than another. Also, so cam catalogs (Crane?) list different cams for different sized engines in a family based on a desired power band, etc. The smaller displacement cams will tend to have less duration for the same power band listed in a category.

I believe Derek joined a month or so ago.

Scottie, I tried to find a spec page in all the Celica links I could find on those sites, but I never found a vehicle weight. If you can get in touch with the guy, see if you can find out how much do they weigh stock. And the engine weight.

Ross, Terry, It's not the tension loads that worry me. It's the bending loads. Slip on spacers, no matter how nice, can spin on the hub, unless they are put on so tight as to stretch the lug bolt. Friction to keep things put is not good high load design, IMO. The US Navy practices taught me that. I agree that adding the concentric lip at the outboard end is good, as is having a nice fit around the hub pilot diameter, as this will limit slippage. On the front, this is probably o.k. On the rear, I'd not try it. If you have the room (thick spacer), I'd prefer seeing a bolt on set up. This way the bending loads are lower since the lugs are relatively short. Having a 4 inch lug for a 2.5" spacer (just pulling numbers out of the air) is just un-nerving to me. If the spacer slips (counting on friction here seems risky to me) by spinning (at the drive wheels) then the lugs bend over a long moment arm (from the nut to the hub) and lug failure can result. On the front (non-drive wheels) this lug bending can't occur with good concentric slip-ons.

Looks Sweet! Those AFR's are pretty! Nice bird too BTW, is that a Zinfandel in your hand as you are installing the polylock on the number 1 exhaust rocker?

My Z when it was Persimmon (color #110)

Jamie, that DOES sound extreme - I love the sound of that project!

The pics are pretty bad, but here they are: http://members.home.net/pparaska1/image/rearbumper/bumper_reinforcement.jpg http://members.home.net/pparaska1/image/rearbumper/bumper_from_aft.jpg http://members.home.net/pparaska1/image/rearbumper/bumper_from_sideaft.jpg

I cheaped out and added a polyurethane bumper with a stud into a hole I drilled in the stock strap. People tell me I'm going to break it though. I could make that thing pictured for about $25 to $30 in materials.

Dan (74_5.0L_Z), your spreadsheet is HERE Maybe SuperDan can put it on the HybridZ site? It's almost 3 MB, and I don't have too much space left.

The issue of spacers, large offset wheels, and increased loads on wheel bearings is a bit tricky. You have to consider only one thing here: If you keep the center (across the tire) of the tire in the same place in relation to the hub flange, everything is fine as you've not offset the center of the tire tread from it's original location. If this relationship is kept as stock, the bearings will be loaded as stock, and all is fine with them. In this case, all you are doing is in effect adding a spacer to the wheel mounting surface of the wheel to move it towards the center of the car so as to keep the center of the tire in the correct side-to-side location with respect to the wheel mounting surface on the hub. That's the wheel bearing issue anyway. Wheel studs: The only issue I can see is that whatever studs you have on the car do not get overloaded. Adding very long studs and using a thick slip on wheel spacer is asking for trouble. If it's only a 1/2" thickslip on adapter, I'd not worry too much. Much more than that and I think that you need to move to a bolt on adapter that is heald to the hub with the stock studs and nuts and has another set of studs protruding from it to mount the wheels onto. For this type of arrangement (bolt on adapter), the length of the studs and more importantly the length that the bending loads on the studs act at away from the surface they protrude from on the hub or the adapter is near stock and they should be fine, if good quality hardware is used. Of course, a good strong material and good structural design of the adapter is important as well. Pete Paraska Master of Science, Mechanical Engineering, (Solid Mechanics concentration) (in case you were wondering if I had any qualifications to be making the above claims)

Try to use more jack stands. That way the front and rear of the car can't bend down from the center of the car. Doing one side at a time is a good idea - that way you aren't weaken/softening the car as much as if you cut both floors. The measurements were to find out where the suspension pickup points and other things were before I cut the frame rails, floors, etc. out (not all at once), to see if the car was square and straight, and to be able to fix any problems as I put the engine frame rails back in the car.

quote: Originally posted by Mikelly: With Coil overs Pete Paraska is running 9 inch wide wheels and 245-45-17s in the rear and NO flares. Jim and I are both running flares... Mike Actually, they are 255/45-17s

I restrained myself from putting a relay on the parking light/running lights . I doubt it's needed as the switch should be able to handle the load IF EVERYTHING ESLE IS OK.

Cool! My sister had one of those when she was in high school - fun little tossable car with a neat little body style. That thing is pretty light, so I'd think it'd give Scottie a run for his money with similar engine mods .

quote: Originally posted by 240Z Turbo: pp, you are correct. At the same dynamic compression, a lower static compression motor will make more power. So is it possible to get good low rpm torque and throttle response with the lower static compression setup, say 7:1?

I'll try to get some pics posted of my rear bumper install tonight. I was thinking about the polar moment of inertia influence when I made the stiffening member that goes behind my stock bumper, but decided what the heck, I'd rather save the rear panel (NLA from Nissan) if someone taps the car in a parking lot or something. That stock bumper is so thin it's ridiculous.

I'm confused. On my 240Z, the headlight rings (were stainless stock, now powdercoated matte black) hold the sealed beam into the headlight housing. Without them the headlight would fall out. I guess the 76 is different?

Cool thread! Grumpy, you first state that making the car fast we can do 3 things: lower it's mass, lower it's drag, and raise it's horsepower. For "fast" (speed) only drag and power matter. For "quick" (ET) all three matter. In fact, all the equations you list have NO mention of mass of the car there. The way I see it, the only thing removing mass from the car will do is to lower the rolling resistance a tiny bit (but you'd over come that effect to add downforce to keep it planted) and the amount of time to get to terminal velocity. Were you just testing us?

A simple 4 link may not be the cat's meow for handling, but add a Panhard rod, etc. and it won't be HORRIBLE, IMO. Try to keep the rear and the linkages, brakes, wheels, tires light, and the unsprung weight won't bite you so bad for cornering.

Sorry, haven't logged in here in a while. To replace the stubs, remove the halfshaft, then the big nut that holds the companion flange (that the halfshaft was bolted to on the outboard end). The nut will be peened over if it's stock. Grind the peened area away and use a long board to lock between some of the lug bolts on the stub axle and get a big breaker bar to loosen the stub axle nut. Now remove the companion flange, and use a slide hammer to pull/hammer the stub axle out of the strut housing. You can use a block of wood and hammer to hammer it out from the inside where the nut goes on instead, if it comes easily, but don't hammer too hard or it might cause a crack at the end of the threads near the splines on the stub. That's if you care about the stub axle. The inner bearing will be stuck in housing (tap it towards the diff from the outside) and the outer bearing should be still pressed on the stub axle. Take the tubular spacer off the old stub axle and use it when reinstalling the new or original stub axle. To replace with another stub axle or the same one with a new outer bearing pressed on (I suggest taking it to a machine shop to have the old one pressed off, and the stub axle shotpeened and magnafluxed with a new bearing put on in their press), I like to install the new inner bearing and use it as a guide when starting the stub axle and outer bearing back into the housing. You'll have to tap the inner bearing back in (on the outer race) to seat it in the housing when done. Install any copper washers, the companion flange, the large washer and use a new 280ZX stub axle nut and torque to spec. Hope that helps,

yeah, yeah, that was me. I did both: support each end of the car on multiple jackstands that I shimmed to get even loads onto and also took measurements with a plumb bob, tape on the floor and measured the height of the pickup points above the floor marks. I then laid the measurements out to see if there was any non-squareness or asymmetry between the measurements side to side. Diagonal measurements help here too. So after I cut the floor out and was about to weld in the subframe connectors and floors, I checked the critical dimensionssure nothing had moved. I even reinstalled the T/C bracket in a more symmetric location on one side, as it was out by a 1/4" laterally before I started tearing the car apart. And you guys wonder why it takes me so long...

(Darned Macintosh - lost my entire post!) I'd start looking at the connectors in the circuits and the ground for them. Relays on the headlight circuit that's fused should not have enough current draw to get the fuse even warm. Same for the park/running light circuit. If all is well, these fuses should not get hot. The connectors should ALL be inspected and cleaned, and the ground on the inner right fender (beneath the wiring harness, in the first foot of harness from the firewall) should be cleaned and rebolted. Also make sure you have a good ground strap from the engine to the body. The other thing to look at is the underside of the fuse box. The little riveted connections of the clips to the copper strips that connect them corrodes (since one part is copper and the other brass, with a slight electrical nobility difference between them). The best way to fix this is remove the fuse box, push the fuse clips through the plastic case, and clean and solder the riveted area, making sure not to build up solder on the side of the connection that rests against the plastic case underneath. If there's too much buildup, the clip won't fully seat and will fail to lock into place in the plastic case. Just a little dab 'll do ya .

Great point ScottieGNZ, about boost, intercooling, HP. Boost is in some ways a measure of the restriction in the intake tract after the engine has ingested all the air it can. If you had a few huge turbos on even a small engine turning even high rpm, the boost would be larger with a restrictive intercooler, piping, TB, manifold, head ports, etc. than with all those areas enlarged but making more power and torque. The effect of actually cooling the intake charge is yet another reason that boost is not really the only thing to look at for power production - a better intercooler will have less loss and more heat rejection, making more power with less boost indicated at the turbo. New idea I'd like to see addressed: I've heard that larger combustion chambers, even with the attendant lower compression, allow for more power production, since there is more room for the mixture above the piston at all times in the induction and power stroke to make power with. So a lower static compression, but running the same cylinder pressure dynamically with more airflow from the turbo(s) could give more power? Does this make sense?