coop

I like that poster too. There is nothing more fun than barreling down through those esses in a Z.

Not clamping the clutch all the way down with the clutch bolts can cause slipping and short or early clutch activation, not foot to the floor activation.

Rob, My ITS engine runs 10:1 comp with no problems although I've never run a tank with less than 100 octane. I'm not sure if 93 octane would work or not.

I'm putting 280zx rear brakes on my 240 per the SCCA E-Production rules. This is what I'd like to do but have some concerns. A friend is doing some research for me on this but I thought I'd run it by the forum just the same. I've also searched all over the web including this site but haven't found exactly this issue. I want to remove all the internal components of the caliper leaving only the Piston, Piston Seal, and Piston Boot. Then, I'll cut off the excess part of the Caliper Body at the point where the helical Push Rod goes through its passage. I'll then seal off the passage leaving a tight chamber for the Piston. I'll also close off the small air passage on the Piston. I'll then be left with a simple lighter caliper with very few parts to fail. The question is, what problem will I then be introducing? Will the Piston drag? Will it pull back too far? Is the helical push rod mandatory for adjustment? My mod looks as simple as the stock front caliper so I believe it should work just fine. Comments? Here is the caliper diagram:

I tried a set of steel drums and they cracked after one session under race conditions. They should only be used for ordinary street driving. I've used the aluminum drums for two decades on the race track and they never warp but do develop radial cracks after about three or four race weekends. They as all brake drums/discs should be constantly inspected if you race at the front.

Nice photos. Send more of the wife!

John, the Porterfield shoe compounds just don't have enough coefficient of friction though they do last forever. The Carbotechs have more bite but they are now having problems with some or their chemical suppliers as they were trying to help me out but couldn't. I do remember a long time ago some shoes that had some bite and yes, I think they were the Ferrodo Green Stuffs that I think you could get through Nissan Comp at the local Nissan parts counter. I like the idea of the grooving but am told that there may be a legality issue there so I never tried it. As far as Hardway's post goes, John, don't you think the best thing for him to do is just upgrade to rear discs and put in an adjustable proportioning valve?

Hey John, I've run Hawk, Carbotech, and Porterfield in various combinations and still get only about 2 - 3 hours out of my pads in my ITS car. I'm always complaining and messing with the shoes trying to get them to bite without dragging too much. It is an art to get it right and I still can't get enough bite in the rear. I start every(double)race weekend with fresh pads and play the shoes by ear, looking at/staring at and bleeding them often. As far as brake upgrades go, I would never spend money in that area on a street car unless I was going to do something like track days and only if I was going to really push it. That mod just isn't needed for autocross as even street pads and shoes work pretty well at autocross speeds. As far as serious racing goes, however, if the rules would allow, the first thing I would do is put simple disk units on the rear and sort them out over a season. I think that is what the vintage guys do and they seem to like it. Not totally sure but I think that is what the E-Production guys do too.

Greg Ira places 2nd again in the SCCA Runoffs E-Production class. He drove well but just couldn't pull it off. Sunday is the last day of races and can be seen on speedcasttv.com. BTW we took the regional championship out here on the left coast with a perfect 10 for 10, but the other day, the engine grenaded while testing at Reno. Four pieces of the motor chipped the windshield of the car I had passed. Later he walked the track and found the #2 rod in the esses. Can you say cha-ching $$$.

Rob, Here is a link to a video of the last three laps of a recent race at Thunderhill. Very conservative driving but my general line just the same. Coop

Great looking car Rob. What a great day at the track! Say, if you want, I can gen up a video lap of TH from my seat if you're interested in my line.

Steve, The reason the mirror sits so low is that my seat is slammed down on the floor. Mounting the mirror up high would require that I look at a greater angle off the driving line. I basically like everything right in front of me. For racing purposes only as they say. I use two long brackets, one on each end off the mirror, that I fabricated out of mild steel. Nothing fancy, just bent at right angles and hose clamped to the roll cage forward, upper, cross tube. It doesn't vibrate all that much but I use it for only a glance now and then as I'm otherwise busy. Now for a street car, vibration and a low mounting position would be a nuisance for sure. Jeff mentioned the panoramic mirror which seems quite reasonable.

Jeff, The Wink mirror is OK. I've had it for years and have never tried any other type so don't know about the panoramic mirror. As far as bump steer goes, IT rules don't allow bump steer spacers so the most that can be done, which I've done, is adjust the eccentric bushings to the 12 O'clock position to minimize bump steer. Also, I drive the absolute stink out of this car and am constantly making lots of very small and sometimes very large adjustments to the steering wheel throughout the course. It is at the limit most of the time as the back end is trying to come around. I also pitch the car when entering corners to set up the drift angles I want. Not everyone drives this way. It is a compromise since I am not allowed an aero package so I have to set the car up that will understeer in the tight stuff and oversteer in the fast stuff. At some courses such as Reno Fernley, I can only go flat through the extremely fast esses when I install the rear vintage spoiler. For sure, this is an old car with lots of limitations in the suspension so I just toss it, catch it, and then steer with throttle. Try teaching that at driver school. This all was way more difficult back when the diff was welded up. What a hand full. I've watched some of my friend's in car footage of the same races and when you look at their steering wheel, it hardly moves at all. They just turn into the corner and drive through with little or no correction. They are also a lot slower and are nowhere getting the most out of their cars. Most folks drive Miatas now which are amazing handling cars with good brakes. A friend sold his Z, hopped in a Miata and immediately went two seconds faster. He said that the Miata was much easier to drive so there it is. I refuse to go the Miata route. Not gunna do it, wouldn't be prudent(George H. W. Bush).

I'm looking forward to seeing your video Rob. Post it again when the link is fixed. Now that I'm sort of Youtube savy, here are two in car videos from this Summer. The first one is of a great race against national and, of course, our regional cars at Sears Point to include a 350Z, and the second is of me doing a huge spin out at Laguna Seca during qualifying. It was looking like a fast one too. Coop

That car on the point is actually a 370Z that has really been dialed in now and is running in the SCCA STO(Street Touring Over) class which includes cars like Vipers and Vettes. He has since added a wing and huge brakes and has gotten quite fast. He has more power, more brakes, and runs about three secs. a lap faster than I can. We do OK, though, with our 200 HP. BTW, I usually go like stink at the beginning of the race but the brakes go away as they are single disks/drums per the Improved Touring rules. All my competition knows it and just waits to pounce. This year, however, we've taken the first ten races in a row and have clinched the championship without even entering the last four races. We will take in Laguna at years end, just for grins. The plan is to retire the car from SCCA IT competition and fully convert to vintage, maybe with disk brakes and a real race engine. We'll see, that is if the wife vetoes the GT40 again. Coop

Will someone tell me if this worked? For the first time I've attempted to post a video on Youtube of a race earlier this year showing in car of the Z in action. Thanks, Coop

I've been using my reversable drill for decades to prime my Z's oil system. Just get about a 16" long 1/4" thick steel shaft (rough dimensions)from the metal salvage yard or Home Depot, etc. Put one end on a grinder to approximate the shape of the tip shown in Captain Obvious's photo(no fancy machining necessary) then afterward, put the other end into your drill chuck. Don't forget to set your drill to REVERSE prior to inserting the thing into the distributor hole and down into the slot in the oil pump, then let her rip. What I really like about this thing is that it verifies the spray pattern coming out of the spray bar. A bad spray hole is discovered instantly. Very cool. Can I get an Amen?

Can anyone point me to a pair of rear suspension link mount braces? You know the ones that are extra wide to enable mounting of the rear sway bar and that of course, hang down to locate the rear a-arm bushings? Mine are totally beat to hell, what with all the side loads and subsequent cracks, welding, re-cracking, and re-welding, etc. I'd like to find some fresh ones that I could beef up. Thanks

John, are they running the track in reverse direction?

You should go to Japan! There are no old cars on the road. The government doesn't want you to keep anything since if you did, you would not be supporting other workers by buying their new stuff. I wonder if there are some neat old items sitting around in junk yards over there? No one would know what to with it now though.

Yes, both temp and elevation have a big effect. The thing is, when it is 100 degrees in SAC, it often is 100 degrees in RNO. See what you get when you run the numbers for RNO at 100 degrees!

Oops, not 85% thinner but 85% of that at sea level(15% thinner).

Rob. I tracked down this cool density altitude site that has a density altitude calculator that is easy to use. You can even input relative humidity to really nail it down. There is even a link there to change over to a relative horsepower conversion. Here is the site: http://wahiduddin.net/calc/calc_da_rh.htm I ran some numbers and in Sacramento, a 100 degree day is like being at 2700 feet on a standard day. If I remember right, most of the time up in Reno, my density gauge reads about 85% as apposed to around 99% at Laguna Seca. This web site calculator bears that out. You basically only will put out about 85% HP in Reno of what you'd get in SAC since the air is about 85% thinner. Maybe some Webber folks or some dyno shops will have some pointers on which jets you will need based on what data you pass them. Just a thought.

Hey Rob. What really affects engine performance is air density. Air density is affected by the air pressure, air temperature, and the humidity. Pilots concerned about the performance of their airplanes use a term called "density altitude" that takes all this into consideration. They get an altimeter setting, get a temperature reading, and then they determine an "effective" altitude which they call density altitude. For example, if you live at sea level in Sacramento and it is 100 degrees outside on a day with a standard altimeter setting of 29.92 inches of mercury barometric pressure, then you will effectively be operating at some higher altitude (say 1000 feet since I don't have a density altitude calculator) where the air is thinner. The effect on air density caused by humidity, is readable but minimal compared to that caused by barometric pressure and temperature so most folks don't worry about humidity. You do, however, need to be concerned about pressure and temperature and their effect on density. You could do as the pilots do by listening to the local weather conditions on an aviation radio, then enter the temp and pressure on a wiz-wheel(calculator) to get density altitude to use as a reference for your jetting or you could do what I do. Use a DENSITY gauge that gives you a density reading to set your baseline. You can come by and borrow it if you want and I'll show you how to use it. What it is good for is once you are in a location on a given day, say up in Reno, you get your car tuned just right, then take a density reading. Then you go down to the Bay area and re-tune the car and take another density reading. Now you have two density versus jetting data points that you can draw a line between on a piece of graph paper. Where ever you go then, you just take a density reading and re-jet your carbs to to satisfy the line. Now this works real cool on my SUs as they are re-jetted with a twist of the knurled knob, but you would have to have a stash of jets handy all the time and it is a bit cumbersome on the Webbers. Now, all this is important to me since I race, and every HP is critical. I do a quick check of the density and re-jet the SUs as necessary just prior to every qualifying session and race and it works great. You, however, should look at the big picture. Are you going to do track days? Are you going to go cross-country over Donner Pass to the valley and how often? Are you looking for power, or economy on these trips? With the density gauge and your data line, you could jet your car for the conditions you will normally drive it under, say an average tune. Then on days when you head out to the track, you could do a quick fine tune just before leaving home. The possibilities are endless. I don't know why folks don't use this sort of thing more often. When I had Dave Rebello build and dyno my recent engine, he said that I had my carbs "right on." Now if I can only find out what is causing the engine fires....... Doh!

Sorry Rob, I could help you if you had the SUs on but not the Webers. I'll be doing some test drives out in the Palomino Valley soon to re-jet my rebuilt carbs so we are up to the same business. Wish I could help you! We should do some joint efforts out there. Nice long roads to wind it out.