katman

Mo' pressure = mo' wasted horsepower. Your call, but I've run 7400 rpm under race conditions with an oil cooler, drilled 280Z cam AND spray bar, with narrower than stock rod bearings at 68 psi hot no problemo. Stock N/A turbo pump.

I was always fond of about 6 inches at the bottom of the rocker panels for a street/track car. Much lower than that and you end up teetering over speed bumps.....

JETDRIVER: I've talked with him not too long ago. I'll email you off line tomorrow with his number.

The strut spacers were intended to correct bump steer when you lower the car, they have a little effect on camber. For the street a half degree negative isn't such a bad thing. Around a degree you start noticing increased wear. My experience anyway. On a 280ZX as you lower the rear you also change toe there, so other mods have to be done to the control arm attachments to correct that. Suspensions are like Mr. Rubik's cube, you change one thing and it affects several other things.

A 225/45-17 will only be about 0.2 inches bigger in diameter than a stock wheel/tire. Anyway, just drill another same diameter hole on either side of the existing strut tower holes, directly inboard and outboard, and file out the remains to form a slot for each of the three strut tower holes. Typical camber plate setups for Z's run about $500 to do the 4 strut towers and require much more work than the poor man's version.

As you lower a Z the front will toe out. How much depends on how much you lower it. Camber will also change to the negative side initially. Whether or not you need to correct it again depends on how much you lower it. As you decamber the front wheels the toe moves back in. Count on an alignment and some way to adjust the camber. The cheapo method is to just slot the strut towers.

Yeah, that's right. However, if the weight of the car is the same as it was with the stock springs, then they would both be compressed to what you are calling the "stiffness" at the compressed height. Your ride height HAS changed and you have the exact same stiffness. Regardless of where it's compressed it has the same rate, which means as far as handling is concerned the characteristics are the same as stock as far as weight transfer. All you have done is raise the ride height. Maybe not enough to notice. Sorry.

What's the application? If it's anything near stock then balance, straighten, and resize if necessary. If it's race then a beam grind and shot peen is nice. Titanium is REALLY nice.

He teach you wrong, Grasshopper. Makes no difference how long the spring starts as long as the weight of the car makes it compress beyond what the constraint of the shock is. If the ride height didn't change, then the spring rate was the same, and the rate at the loaded height is the same. As stated previously, stiffness is a function of wire diameter, material, coil diameter, and number of coils. stretching one out 10mm and then compressing it back doesn't change the stiffness. Recovering faster has more to do with shocks than springs. Transistions are shocks, steady states and ride heights are springs. I'm with Bob. All cars handle great at 9/10ths.

Nope. Regular stand, engine supported from the back, no problemo.

Last one I measured was 3.500 inch circular and that was for an L24. They compress to thinner than stock, about 0.040 versus 0.049.

Huh?

Like johnc said, typical ITS 240Z. No flares. 8 point SCCA cage, 14x7 wheels, 225-50 Hoosier S03 rubbers, 400/350 spring rates, 5-1/4 inches at the rockers, and SERIOUS shock development. Interestingly ITS rules don't allow the cage to pass through the firewall, so just a strut bar up front. Sorry, no website.

Real east coast SAE calibrated 203. I never thought I'd see it in an ITS motor. A couple years ago we discovered something in the header configuration and it took until this year's ARRC rebuilds to figure out how to match the carb side of the equation. As usual, Sunbelt persued the science, not the smoke and mirrors. Kudos to Jim.

Not to mention the fact that a Z suspension is already a "coil over". Now if you're anticipating a lot of spring swaps looking for the ultimate AutoX or road race setup, then an adjustable spring perch with 2.5 ID springs and camber plates, blah, blah, blah, makes a lot of sense. But for a street car I've made some great handling cars by whacking a few coils of some 280Z rears for a grand total of zippo dollars.

That'd be about right. Most of the numbers bantered about by GA-Z Club members are products of Sunbelt's engine dyno, so that's real SAE calibrated hp and not some inflated sales pitch. Always start with more cubic inches (L28) on the bottom end unless constrained by rules. With 9.5 compression, pump gas, mild cam, 1.5 diameter primary headers, 2.5 diameter exh with Dynomax or Borla muffler, modified EFI or carbs, 200hp is easy with a stock bottom end (say $1500 for the peripherals and minor machine work). 225 easy after an ITS type rebuild (1-2% leakdowns, balanced, blueprinted, spec valve job) with the same peripherals (add another $4000 for the machine work and new parts). 250 NA with all of the above, a Sunbelt cam and a $1000 day on the dyno. 300 NA with all of the above and a couple grand in headwork, or about $10k total. No problem. All it takes is money....

Well, our data acquisition system measures 1.45g at turn 6 at Road Atlanta, and about 1.2-1.3g in most other corners on DOT approved tires (Hoosier S03, like what was the DOT thinking?) for an ITS prepped 240Z so yeah, +1g lateral is possible on a 1977 280Z but not so's you'd want to drive one on the street that way. For the street, urethane bushings everywhere, slightly stiffer springs and bars, real shocks, lowered, and hideously expensive ten thousand miles if yer lucky tires, and you might get near a g and still be able to go over a speed bump now and then.

For the street I'd stay away from welding the diff. No fun dragging around one tire or the other all the time. In th rain it promotes wicked understter and eventually breaks other parts due to the added stress. The rest sounds like fun though.

Been there, broke that. On the street with mild motors the Nissan R160's usually last a good while. Not however under AutoX or ITS racing. For a 4.11 or 3.90 we always use the R180 from the front of the 4wd Nissan trucks.

Uh, how big is said budget? That pretty much determines lots of things, and sorta helps us cut to the chase regarding what parts/options etc.

Me thinks Dan J. actually has V8, but the pics of the L engine cars with a dual exhaust I'd bet are hurting themselves versus a single. Even for built motors.

John is of course right, rear brake cooling is generally not an issue even in ITS racing. The undercar ducts because of their ground proximity usually just serve to redirect small pebbles and other foreign objects into the brakes. For a quarter window mounted NACA duct a la NASCAR it'd probably only be effective with the door windows up because of the sharp leading edge and goofy airlow about the rear quarter with the door window down. Note the smooth leading edge of the B pillar on your typical Winston Cup car. They also put 3" fans in line with the ducts if need be to coax the air in.

Lots of shops will claim to be able to rebuild a Z motor, but you'll never end up as good as factory unless you spend big bucks for something like a Sunbelt (since you're in GA). Best value for stock is to buy a factory reman shortblock and then have Sunbelt do an ITS level prep on the old head.

Awesome exhaust work Dan. What's the basic config of your engine? All our work with the L6 says a dual exhaust kills the power, but since you have a crossover tube I'd pay to see how your system compared to a more conventional 2-1 single with your engine. Looks good.

Actually we're limited to 0.5 point increase in comp ratio over stock, or 9.5:1. Usually use one of the early E31 combustion chambered E88's and take off less than 0.020 or you end up exceeding the compression ratio allowable. You're also allowed 0.040 overbore. Lots of time spent on carb and exhaust tuning, and horrendous amounts of development in reducing friction without platings (banned a couple years ago). Almost zero leakdowns. Meticulous machine work, assembly, and dyno tuning like John says. Of course Rebello has claimed 200 hp for an ITS motor for years, but that's West Coast numbers