steve91tt

I am in the market for a set of dedicated track rims and tires for my 240Z. I am currently running Eibach springs, Tokico shocks, larger front and rear sway bars. Rebello 3.0 under the hood. I like what I have read about the Toyo RA1 tires but I am not sure what the best size would be for my setup. I'm liking the sound of a set of 205/50ZR15's on a set of 15x7's like this... http://www.thezstore.com/page/TZS/PROD/WWC19/25-1067 I think this should get me the grip I need without rubbing, coil overs or fender rolling. It should also give me a little lower gearing as the radius of these tires are smaller than stock. Lower gearing would be nice as I have the stock R180 in the rear. The smaller wheel and tire is also lighter and cheaper. I haven't read about anyone running this sort of setup at the track. Is there a down side I'm not considering? Is there something different I should be looking at?

It's just south of Houston on Hyw 288. It's open to the public for track day events. The next open event that I know of is the "Red Meat and Racing fuel" evening BBQ and track time on the 24th. I would love to make it out to that one. Details on the following site... http://msrhouston.com/

16 turns, 2.4 miles. Very nice course for momentum cars like the Z. Thanks for the tire info. Time to go shopping!

I simply zip tied my iphone to the rear view mirror. I mounted it hanging off to the driver's side and put a piece of rubber behind it. Very securely mounted and still lots of mirror left to see what's behind. I run Harry's lap timer app on the phone. It uses the phone's internal GPS, accelerometers and camera to record lap times, graph lap speeds, graph g loadings, record video and lots of other statistics. Great little app for the track.

The car handles spectacularly well given the fact that I am running on 400 tread wear tires. I'm now in the market for a set of track rims and tires. I'll keep the current ones for daily driver use and swap them out when it's time to play.

I spent a great weekend running the driver's edge event here at the Houston MSR track. Tonnes of fun and the Datsun did great! Here's a couple of laps from the last session today.

Great build thread. Thanks for the link.

Thank you!

Sorry, what does mbt stand for?

Outstanding. Thanks Arne.

I am in the market for a new head for my 3.0 liter bottom end. I am currently using the stock 1973 E88 head and cam with about 10:1 compression. The car runs great if I keep the timing less than 30° total advance on 93 octane. If I run more timing or less octane then I get detonation. From what I have read much of the issue is the shape of the E88 combustion chamber. I like what I have read about the performance of the P79 or P90 head. I may loose a little compression compared to the E88 but it should flow much better in my setup and allow me to run more timing. Question: If I run a FI head with my stock SU intake will the intake runners line up or will FI notches in the head cause issues? Do I need to have the FI notches welded up?

The butterflies are adjusted by the unisyn. If you have them open too much but sync'ed then you should idle high but not have hesitation issues. Just an idea...you may have a vacuum leak. Now that it idles, have you tried a shot of carb cleaner directed around the intake gasket area and at the throttle shafts. If the idle changes with a squirt of carb cleaner then you have a leak. If it's at the gasket...easy fix. If it's at the throttle shaft...new carb(s).

Exactly what I want to start playing with. Tinker, tinker, tinker. It's a disease.

I'm in the market for a big valve head and cam to play with. I'd like to try my hand at some minor porting and polishing. If you know where I can find a solid one for a good price let me know!

I'd love to make it up to Cresson some time this year but there are still a few spots open at the Houston track for next weekend. Come on down if you've got the time.

I bumped it up a couple of degrees and did a few runs. I reproducibly got very light detonation near the top of 3rd gear. Nothing in 1st or 2nd just 3rd. The AFR was in the high 12's when it pinged so I'm pretty sure it's not fuel related. I did not get any pinging with throttle roll (at least none that I could hear). Backed it down a couple of degrees and all is good again, no more detonation. I will run a few gallons of 110 octane leaded mixed with a full tank of 93 octane at the track. That's what I did last time and the car pulled like a freight train. Can't wait!:classic:

I gave the 30wt oil a try in the dash pots. I did not notice any difference compared to the 20wt. The 20wt was a significant improvement from the AFT with regards to a lean spot on tip in but that seems to be near the best weight of oil for my setup so I'm going to go back to the 20wt. I think that's all the tinkering I'm going to do for now. I'm spending two days on the Houston MSR track next weekend (driversedge event) so I want to put some miles on the current setup to make sure everything is lined out. I don't want surprises on the track.

Agreed. The Mallory system never made sense to me. Great distributor though.

I hooked the vacuum advance back up and went for a test drive. All seems as it did without the vacuum advance but I guess that's a good thing. I also noticed that I had to force myself to drive below 2500 RPM. I find that I don't drive at that low an RPM very often unless I am accelerating or idling. As I understand it the Mallory vacuum advance has no effect while accelerating or idling or any condition above 2500 RPM so I don't see any advantage to it. But I also don't see a disadvantage so I 'll keep it hooked up for now.

I am running an RX7 electric fuel pump at the tank to boost the stock mechanical pump. The RX7 delivers about 4psi to the mechanical, it's nice and quiet, easy install and easy to find new or used. I will try hooking back up the vacuum advance this evening and see if things have changed now that I no longer go excessively lean on low RPM tip in.

I agree. I would love to turn the mixture nuts in a turn or two to lean things out at idle and WOT but when I do the car goes quite lean on the highway.

The advance curve I am using has all of the mechanical advance in at 2500RPM. The vacuum advance on the Mallory distributor will not allow advance beyond the maximum mechanical advance. Therefore, in my case, the vacuum advance only serves to increase the timing when cruising below 2500 RPM. I tried vacuum advance with my setup when I first got the distributor and the car tended to hesitate and buck more at at low RPM so I disconnected it. I now understand that this hesitation may have been partially caused by a lean condition due to low viscosity dash pot oil (discussed above). I have gotten rid of 80% of the lean condition by going to 20wt oil so I may go back to the vacuum advance. I may try 30wt oil as I am still a little lean on transitions at times. It may make things worse but it's a quick, easy experiment to run and I can't help myself. I must tinker!

I'm running 10:1 compression on a stock cam so I can't go much above 30 degrees of total advance without pinging. I have a Mallory dizzy so I can change the curve fairly easily. I will try giving it a few more degrees at idle and see what's what. Sorry never tried a colortune.

Thanks for the feedback guys.

No vacuum advance currently hooked up. I do get a little surging if I have it leaned out to cruise in the 16's. Good news...I changed to 20wt oil (from ATF) in the dash pots and the lean spot at tip in is gone (condition #5 in original post).