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John Coffey

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Everything posted by John Coffey

  1. John Coffey
    My point was that we made no change that would have increased the fuel or air used in the engine so the "increase" in horsepower was just an anomaly of the chassis dyno. IMHO, chassis dynos are tuning tools and not to be used to generate bench racing horsepower numbers. In the past I've had two identical L6 engine built to SCCA ITS specs, one was a L24 and the other was a L28. Same carbs, same cam (stock), same headers, same ignition, etc. Probably as close to same as possible. The L24 engine made more horsepower then the L28 because I could spin it to 7,500 rpm and tune it to take advantage of that rpm. The L28 made more torque and was easier to drive on the street. If I remember correctly, the L24 made 190hp on the engine dyno and the L28 made 181hp on the same dyno.
  2. John Coffey
    Horsepower numbers... My racing 3L made 325 hp on Kinetic/Sunbelt's SAE certified engine dyno. It made those numbers repeatedly on different days. The engine was shipped out here to SoCal and put in my race car. Jim Thompson came out and we spend 1/2 a day verifying the installation at Superior Automotive's chassis dyno in Anaheim. 282hp to the rear wheels is what we measured. We did some tweaks to the install due to some cooling concerns and went back the next day. 294 hp to the wheels with no changes to the tune, fuel, etc. The car did not magically pick up 12 horsepower.
  3. John Coffey
    I've seen a 2.4L L6 engine make 208hp on a SAE certified engine dyno running a "stock" cam, SU carbs, headers, and a good ignition. That's a $6,500 road racing ITS engine build. For these L6 engines, its not about the parts, its about the care and effort put into the build. That's why professional engine builders like Rebello, Sunbelt, Slover, etc. can make more power with much less then the garage builders. Just slapping on a cam, headers, and triples will get you very little for the cost. Its all about the time and effort put into the parts selection, blueprinting, installation, testing, and tuning.
  4. John Coffey
    Actually, Nissan Motorsports USA has one new 4.88 110mm ID ring and pinion available. $660 last time I checked.
  5. John Coffey
    I've flat towed 240Zs using the tow hooks and I've had race cars pulled out of the mud using the front tow hook mounts and the rear bumper bracket mounts. These cars are not fragile little paper oragami sculptures. If your'e going to do this often, remove the front tow hooks and make brackets that bolt to the tow hook mounting points using all the bolt holes. You can also add a brace to the bracket that goes from the bumper bracket mounting holes thus spreading the load out in four places and across six mounting bolt holes in the chassis.
  6. John Coffey
    Given the current levels of technology in TIG and MIG processes there's no appreciable difference in the strength of proper welds in carbon steel and aluminum. Where TIG has advantages is in stainless steel, nickel steel, titanium, magnesium, berylium, and other more exotic alloys. But for anything on a 40+ year old Datsun MIG and TIG are equal.
  7. John Coffey
    Gas welding takes more skill then MIG, TIG, or Stock welding. Good luck...
  8. John Coffey
    Strut is the steel tube that is part of the suspension. Shock is the suspension damping unit installed inside the strut. Its all about bump travel. If you lower the car you reduce bump travel by close to the amount you lower the car. The S30 starts with about 3" of bump travel before you're on the bump stops. Lower the car 2", and now you have 1" of bump travel, which is inadequate for a street driven car. You can get about 1.5" of that bump travel back by shortening the struts and installing shocks with a shorter shock body. ALL shocks installed in struts must be positioned at the top of the strut tube. This may require a spacer under the shock in the strut.
  9. John Coffey
    A good welder can do anything on a car with the crappiest equipment found in the gutter. A bad welder will destroy anything on the car with the best equipment money can buy.
  10. John Coffey
    "This is a race only part and we will not sell it for a street driven car."
  11. John Coffey
    Tooting my own horn. Installed on probalby 25 racing S30s around the world including two S30s that are running the East African Safari rally next week. http://www.betamotorsports.com/products/products_main.php?cat=3&scat1=41&scat2=25
  12. John Coffey
    Read the HybridZ link above. I've written it all out.
  13. John Coffey
    The 5020-F springs are progressive and are design to coil bind the top 3 or 5 coils. The gaps in the remaining coils give 1.5" to 2" of bump travel before coil bind. Ideally you're on the bump stop before then but most 40+ year bump stops are rotted away and few people replace them when installing new springs. The Tokico HP 280Z springs are a better choice for any any S30.
  14. John Coffey
    Ignore offset and focus on backspace when ordering custom wheels. I used to run a 15 x 8 custom wheel with 4.5" of backspace but I had to run coil overs to gt the proper clearance. Some people claim to fit this wheel with the stock 5" OD springs but I'm skeptical. I haven't heard the term roll couple in a while. Currently in suspension setup we treat each end of the car as as separate item and roll couple may only come into play when calculating total roll stiffness as part of the anti-roll bar design.
  15. John Coffey
    I have never, ever seen a hub fail at the center. Not from curb impacts, not from lateral overload, not from stress risers and resulting fatigue failures. The failed hubs I've seen bend/fracture from the wheel stud hole out to the edge of the flange. That's on 240Z, 280Z, 350Z, BMW E36, and Porsche 944 hubs. On a 240Z front hub the material at the flange is at its thickest at the hub center. Has anyone else seen a failure from the hub center (honest question, not being sarcastic).
  16. John Coffey
    I used to think that too until I watched No Country for Old Men. I don't want to meet Anton Chigurh.
  17. John Coffey
    Take the oil pump off the engine and remove the distributor. Remove the shaft and inspect it.
  18. John Coffey
    Check the ungreased and uninstalled wheel bearing rattle, play, and spin spec in the FSM.
  19. John Coffey
    Disconnect the front brake line at the MC and the brake lines at the calipers. Squirt a whole can of Brake Kleen through the lines. Blow air through the lines after. Reattach the lines and bleed. Also, check the pushrod in the booster to make sure its going all the way back. Sometimes it needs to be shortened a bit.
  20. John Coffey
    Again, all the SU mods listed above are for track use where you're at full throttle or nothing. On a 200hp track 240Z running SUs the throttle is a light switch: brake, turn in to the corner, slap the throttle to the floor. In some cases the mods above will not allow the car to idle and you will have to keep it running by blipping the throttle.
  21. John Coffey
    It depends on what your goals are. A mild cam upgrade will work with the stock exhaust manifold but you might get a little more with a good header. For racers that little more is well worth the effort because the car spends so much time at full throttle. For a street driven car that spends, maybe, 2% of its drive time at full throttle, its probably not worth the effort to swap out the manifold for a header.
  22. John Coffey
    There will probably not be any performance difference between the stock exhaust manifold and any of the headers mentioned so far in this thread. IMHO, if you take the money you would spend on a header and spend it cleaning up the inside of the stock exhaust manifold, port matching it to the head, and getting a real ceramic coating done (not JetHot Sterling) then you'll be better off for your intended street use with a stock cam.
  23. John Coffey
    We're not cruel at all. We're just a dose of reality in an automotive world filled with fantasies.
  24. John Coffey
    And now to answer the question... Simple performance suspension mods will generally not decrease the value of a 280Z: Shocks Springs Urethane bushings in a few key area Anti-roll bars A +1 upgrade for the wheels and tires generally doesn't have a negative affect on the value of a 280Z. Upgrading the ignition, adding a mandrel bent 2.5" exhaust system, installing a K&N air filter in the stock air box are generally OK to do from a value perspective.
  25. John Coffey
    "This is my Wife's car and it currently is worth 19K" Then that is the most valuable 280Z in the USA right now.
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