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jgkurz

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Posts posted by jgkurz

    What causes this brake issue?

    in Brakes, Wheels, Suspension and Chassis

    Posted · Edited by jgkurz

    Hi All,

    I have the typical Toyota 4x4 S12W front brakes and 240sx rear disk brakes on my 77 280Z. All parts are new and bedded in properly. I have bled and vacuum bled the system till I blue in the face using ATE fluid. I use Porterfield R4S pads and have excellent fade resistance. The master cylinder is a 280ZX 15/16 type. I have even participated in a HPDE track day where I punished the brakes with no issues or severe fade. I have an adj proportioning valve that is biased safely towards the front. The suspension is all new and urethane most everywhere possible. The car's alignment is spot on and tracks and handles well.

     

    For some reason the front right brake will lock up if I mash the brakes in an emergency stop. At the drag strip the other night I hit the brakes a bit hard and again the front right will lock. Below is a picture of an emergency brake at probably 80mph.

     

    Any suggestions what is causing this? Should all four lock if the pedal is pressed hard enough? BTW, this skid was not intended and was a bit unnerving. Thanks for your comments.

     

     

    post-388-12738110823675_thumb.jpg

    Ross' Sleeper Z

    in S30 Series - 240z, 260z, 280z

    Posted · Edited by jgkurz

    The rear suspension is on hold until I can get Arizona Zcar's rear parking brake setup. Dave is working on it. He test fit it the bracket and caliper but the stock cable does not work with it. He needs to design a new cable.

     

    I disassembled most of the front suspension. The suspension parts are going to be powder coated and reinstalled with urethane bushings everywhere.

     

    I had an external wastegate put on my exhaust manifold and an oil return fitting welded on my oil pan. PowerFab Automotive in Houston did all the fabrication work for me. I dealt mostly with Nathan in the beginning. Once we got down to the specifics I talked to his welder (I don't remember his name). This is the way it should be. I like to talk to the guy who is actually doing the work. The work was done very quickly despite the fact that they looked very busy. I dropped the parts off on Friday around 11:00 and received a call that afternoon that the work was done. I picked up the parts Saturday afternoon. I'll probably have PowerFab build my down pipe and exhaust when it's time.

     

    And without further ado, here are the pictures.

     

    Nice short wastegate pipe and compact TiAl MV-S wastegate.

    img_3351.jpg

     

    PowerFab's wastegate pipe places the actuator housing about 1/4 inch from the block.

    img_3353.jpg

     

    Another camera angle

    img_3355.jpg

     

     

    The welded exhaust manifold looks great. I read your whole thread but didn't see what caused you to abandon the turbo header. Can you elaborate? I purchased a header a while back and ended up selling it because it used a T4 flange and clearances were questionable. I also run A/C. The smallest GT35R vband T4 turbines I could find were.68 non-divided and .78 divided if memory serves. I didn't want to go backwards regarding turbo lag so I stayed with the cast iron manifold.

     

    -John

    Clicking from rear when backing up - R200LSD or U-joint?

    in Drivetrain

    Posted · Edited by jgkurz

    The LSD does absolutely nothing unless you're turning.

     

    Thanks Jon. I was hoping you'd see my post and reply. Actually I'm glad to focus on something other than the diff. Much cheaper.. :)

     

    sounds stupid, but it could be one of your driveshaft to diff bolts sliding back and forth in its hole. I had this happen once, really strange noises, like the ones you're describing.

     

    Interesting. I will pull the driveshaft to inspect the u-joints and bolts. That would be any easy fix.

    Clicking from rear when backing up - R200LSD or U-joint?

    in Drivetrain

    Posted · Edited by jgkurz

    Hi All,

    I have a strange noise from the rear of my 77z when backing up. The description is very similar to the below thread however my drive shaft is not hitting my swaybar.

     

    http://forums.hybridz.org/index.php?/topic/74366-clicking-noise-when-backing-up

     

    In summary, I hear a click clack click clack from the rear of my car when I back up the car. It happens often but not every time. On a rare occasion I can hear it slightly going forward. I only hear the clicking after letting the clutch out at low speeds in 1st or reverse. I'm am positive the rear CV shafts or brakes are not to blame. I believe the problem is either the R200 LSD or a U-Joint.

     

    I put some hard miles on my car at a track day and since then I have noticed the click clacking.

     

    Questions:

     

    1) Could worn or slightly low diff gear oil cause my LSD clutches to make this noise? I use Amsoil synthetic without a friction modifier (as recommended)

     

    2) If it's a U-Joint, I assume I take the drive shaft out and check for smooth moving joints?

     

    3) Could a wheel bearing cause clicking? When the car is jacked up the wheels spins freely and without freeplay. Not a fun job to change one of these.

     

     

    Thanks!

    Insider deal to buy used Ferrari

    in Non Tech Board

    Posted

    Driver or car? They can actually do very well on a race track:

     

     

    This guy is a bit wimpy (typical street Ferrari driver) but I didn't see anything bad from the car. I would have to shoot most of these Vintage drivers - they just cruise down the center of the track. 'Course, there is a shining example of why you probably should keep the Datsun.

     

    I enjoyed the video. It looked like he was taking it easy on the car and only passed when there was plenty-o-room on the straight. Personally if I was driving a Ferrari I'd have a hard time letting an Alfa, Triumph or Datsun guy think he was faster than me :mrgreen:. The white 260zed was a bit brazen I thought.....

    Garrett GT35-R surge questions.

    in Turbo / Supercharger

    Posted

    Mid corners... don't even get me started on boost threshold coming in halfway through a corner and loosing traction. It was the reason for the whale tail being added to my 240Z...

     

    Unfortunately the whale tail is only helpful at higher speeds. 2nd and maybe even 3rd gear corners probably wouldn't benefit.

    Garrett GT35-R surge questions.

    in Turbo / Supercharger

    Posted

    I am not trying to say make a dyno queen with a bigger turbine housing, but if you are not coming back down below 3500-4000 rpms when shifting do you need a .63 housing? Its all about compromising things at this point.

     

    That might be fine for a drag racing application but an oversized turbine on the street, autocross or even for road racing would make power delivery a PAIN to modulate. Sure, a BIG turbo will usually make more peak power but can also make your engine feel like a 2-stroke. Like you say, it's about compromise. Peak power is only one part of the equation.

    Wilwood versus 4x4 vented .. pro's vs con's

    in Brakes, Wheels, Suspension and Chassis

    Posted

    I run the Toyota S12W calipers with Porterfield R4S pads. I have been surprised by their stopping ability even after an 82deg F track day at PIR with my near 3000lb 280Z. Front straight and rear straights both were both between 130 and 140mph. I still had acceptable pedal and fade after several laps. I'd love to have a setup like the Arizona Z race calipers/rotors but I'm not sure the extra braking capability would be that helpful with a car that is on the street mostly. The big calipers and rotors also may not save much weight. Just my .02C

     

    One other tidbit. I highly recommend painting your calipers with VHT brake caliper paint. I used black but there are other colors. It's looks much better behind a nice wheel vs a rusty caliper.

    Garrett GT35-R surge questions.

    in Turbo / Supercharger

    Posted

    Phil, I highly recommend you not go to a larger turbine. The .63 is a perfect match for the L28. You might get more peak power from a .82 but the spool would noticeably suffer. Like you, I used to have a highly custom internal gate. I could never get it to stay closed no matter how big my spring was. All porting the wastegate offers is to provide a larger surface area for exhaust pressure to push on the flapper door. Remember, the higher the boost the less wastegate size you need since most of the exhaust is used to move the turbine. As a fix, I made a custom divorced wastegate port that allowed a 40mm Tial external gate. All my problems were solved. The fabrication was a pain but I can almost guarantee that your boost issues will be gone. You may still have a surge problem with stock components but the boost flutter would be gone. Let me know if you want more detail. Your car should easily be over 400rwhp.

     

    I'm curious on one other point. Are you really running a 2mm head gasket with stock pistons and a ported head? If the answer is yes and your combustion chambers are worked over you are well under the stock 7.4:1 static compression. That's too low in my opinion.

     

    P.S. On an external gate, the rule of thumb is boost should not exceed 2.5x the spring pressure. 2x is preferred.

    Any spec clutch reviews

    in Drivetrain

    Posted

    Check this out:

    http://forums.hybridz.org/showthread.php?t=109674&highlight=SPEC+Clutch

     

    Vette, Viper, and Supra guys love them, but they have a really bad rep on Datsuns.

     

     

    I ran the 323 Spec clutch for a bit. It would slip and chatter as soon as boost hit and my engine torque peaked. I tried two separate new clutches before giving up on Spec. Tech support claimed the clutch was rated to far exceed my power and that there was something wrong with my installation. I had a custom clutch built next and haven't had a problem since (about three years of abuse)...

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