katman

Last time I looked anything but a stock front diff mount was illegal in ITS, so I don't know about it being a "popular" part in that class of racing.

It did not have a crossover. That may help, however, we did do some limited testing with different lengths of secondary pipe (the pipe between the collectors and the Y that finally brought it all into 1) after the headers, and the sooner you collect it ino 1 the better. For our application anyway. I doubt the crossover would help much in a 6 cyl. I think you'd still be worse off than with a single, but I could be wrong.

OMG, I'm amazed at the effort and detail in this thread. I was too lazy to put Xenon bulbs in my Z so I bought the whole damn BMW, E46 330ci. Now I feel cheap... I'm gonna go apologize to my Z...

In the very early 90's we ran a dual exhaust on the ITS car behind Clifford Research headers with 20 inch long megaphones on each pipe straight out the back. 108db on the back straight at the old Road Atlanta and it was the sweetest sound. But two things killed that setup- SCCA lowered the sound requirement to 98 and we discovered the dual exhaust cost us about 10 hp....

Broke the needle clean off in 7 laps, on a 325 degree gauge. To break the needle off you had to go past 325, down across the bottom of the gage, and run the needle into the stop at zero. Us, and least a couple other competitors, went through the gammet of different fluids, bearing preloads, etc. before happening upon the BG MGC. Some guys still puke fliud out after every session and change fluid constantly, even with Redline green. Don't know if they use the MGC or not. In our case it wasn't the LSD as much as it was the gear ratios. At 3.7 and below we could run all day. At 3.90 and 4.11 we'd be puking fluids before 10 laps at RA before the MGC. In ITS you couldn't use a cooler, so once you generated more heat than the diff case could shed it was stinky time.

Awfully short primaries on the NA. What's the application?

Actually I have a set. Boy is this thread, uh, historic. PM me and we'll work something out.

Why bother with the clevis at the LCA end?

Main hoop diagonal vs X brace to rear: I think a properly located diagonal in the plane of the main hoop is the most efficient and stiffest way to protect the driver's head against a rollover. You basically form a truss with the peak at the driver's noggin'. An X-brace to the back with no diagonal has some lateral stiffness for the case where the roll contact is on the side, but for pure vertical you have to rely on the bending stiffness of the hoop bar. Not good. With the diagonal both lateral and vertical impacts are resisted- no need for the X-brace IMHO. I don't see the X-brace as very efficient for any anything- a waste of tube. Not sure what the sanctioning bodies who require it are thinking.

snicker...Not at Road Atlanta. A lot depends on the track. At RA the only thing that holds up is a Hawk HT-9, now obsolete. The HT-10's that replaced them are close. Also takes 3 ducts to each side: one to the "can" that splits the air over each side of the disk, one to the underside of the caliper to cool the hub and bearings, and one between the wheel and the top of the caliper to blow over the outermost diameter of the pads where the heat is the greatest. Rear brake balance is critical here too. On the other hand, you can run Hawk Blues with no ducts at Roebling Road all day long.

No diagonal in the plane of the main hoop? Nice big kink halfway up the main hoop with no horizontal from kink to kink? I wouldn't race with that cage!

"Door bar design seem to be good enough for Subaru Rally cars:" Since when are they any smarter than anybody else? I'da told them the same thing. Nice work though!

Nice work. Like to see the main diagonal before you weld it in. I prefer my door bars about 5 inches apart with a couple verticals spacing them- stiffer and breaks upt the space where pieces of the other guy's car can penetrate when you get T-Boned. Did I say nice work?

Because every time we run one in a race car the LED falls out. Had one in a 1970 Mustang way back in the day and loved it. Quit using them when we had failures in race cars. Too many other good options...

Not to mention the fact that a Unilight isn't is as good as any Nissan electronic distributor.....

I'm with John. There's lots wrong with this car that you proly don't even see yet.

John's right, of course, you're a "tweener". And Koni/Bilstein will proly not want to put in the time to really figure out what you need- they're dig up some ole full race or hot street recommendations. Face it, we're talking old cars. I'll offer up my "old guy who spends more time in a Caravan than a Z" opinion again: For anything that doesn't get to the track on a trailer, I'd err on the side of soft and here's why. First, I've /owned/driven/built several nice 240Z's that were in the 115R/145R-185F/185R range with typical "other" street mods on several race tracks at various times and have had as much or more fun as I have in a full out ITS car. And been nearly as fast. Tires have more to do with cornering speed than another 50-100 in/lbs of spring at the level of driving most people we be doing on "track days". Second, it's a lot easier to get up to speed during a weekend in a softer car than a stiffer car. It might not be the ultimate potential of your car, but let's be realistic about the point of a track day. Fun, not tenths. Third: shocks for a streetable car are easier to come by, cheaper, and not as critical as shocks for a stiffer car. I doubt anybody in the 200-250 range really has the shocks that are "best" or appropriate. I bet damn few ITS racers are capable of knowing what they have or need either. Fourth: I don't like the long term affects that stiff springs have on Z chassis' and other parts. The shock loads are huge (for the right shock). and finally: If the vavling isn't spot on, and you're actually good enough to know it, you're in for another revalving, and maybe another... [aside: this really really pissed me off when SCCA caved to the class whiners and outlawed remote reservior adjustable shocks for ITS].

John's right, of course, you're a "tweener". And Koni/Bilstein will proly not want to put in the time to really figure out what you need- they're dig up some ole full race or hot street recommendations. Face it, we're talking old cars. I'll offer up my "old guy who spends more time in a Caravan than a Z" opinion again: For anything that doesn't get to the track on a trailer, I'd err on the side of soft and here's why. First, I've /owned/driven/built several nice 240Z's that were in the 115R/145R-185F/185R range with typical "other" street mods on several race tracks at various times and have had as much or more fun as I have in a full out ITS car. And been nearly as fast. Tires have more to do with cornering speed than another 50-100 in/lbs of spring at the level of driving most people we be doing on "track days". Second, it's a lot easier to get up to speed during a weekend in a softer car than a stiffer car. It might not be the ultimate potential of your car, but let's be realistic about the point of a track day. Fun, not tenths. Third: shocks for a streetable car are easier to come by, cheaper, and not as critical as shocks for a stiffer car. I doubt anybody in the 200-250 range really has the shocks that are "best" or appropriate. I bet damn few ITS racers are capable of knowing what they have or need either. Fourth: I don't like the long term affects that stiff springs have on Z chassis' and other parts. The shock loads are huge (for the right shock). and finally: If the vavling isn't spot on, and you're actually good enough to know it, you're in for another revalving, and maybe another... [aside: this really really pissed me off when SCCA caved to the class whiners and outlawed remote reservior adjustable shocks for ITS].

I'd proly go with an Illumina and slightly lower spring rates for a dual pupose car.

I'd proly go with an Illumina and slightly lower spring rates for a dual pupose car.

Valvoline Racing still has about .2% zinc I think, and Kendall GT-1 Racing used to have about .16. We used that in our IT cars with good success. However, I don't think the GT-1 Racing is available anymore, and their conventional high performance oil is only about 0.13.

"the motor pulls so much air it sucks more fuel then it really needs on su's hence the leaking shafts being a good thing to let some more air in to lean it out a bit" Riiiight.

"not true." Ok, I'll bite.

Most SU poblems are caused by worn throttle shafts - which most rebuild kits aren't going to address. I'd buy rebuilt carbs from Z Therapy. Better than new.

Piston engine airplane engines use multi electrode plugs for longevity. After one electrode quits being the favorite (gap increase or whatever) the next one is ready to go. Since airplane engines have dual magneto's you can have the polarity different on each one. Standard proceedure was to clean and gap the plugs, then test them (yup, spark only goes to one electrode at a time), and then rotate them so they would be on a different mag for the next 100 hours. That way, metal that was deposited from center to outer would then be redeposited from outer to center and visa versa.