zguitar71

I have seen the gear reduction machine, it resides at the MIT museum in Cambridge MA. it's pretty cool. On one end there is a shaft spinning away and on the other end there is a shaft in concrete and in the middle there are gears that moves slower and slower as you get toward the concrete side. The movement becomes imperceivable about 4 gear reductions back from the concrete block. I watched the machine for a long time, it is really hard to wrap your mind around the shaft never breaking on the concrete side.

Rolling the fenders will not do it, you will have to have flares. Read the group buy threads more and you will find more info.

There appears to be a spacer making up the difference on the 35 tooth gear so leave it off of the 3.9 gear and it should be fine. You might need 1mm spacers for the bolts because the 3.9 has 10mm bolts and the 4.37 has the 12mm bolts, search it and you will find good info about it. As far as a lower ratio, 4.37 is low already, did you mean Higher?

The other thing about R compound tires is the soft tread (when warm) will pick up all types of road debris like bits of glass or any other sharp item that could eventually work its way into the tire carcass running your tire. R compounds are really built for the track even though they are DOT approved.

If the air temp is warm and the pavement is warm the tires will get warm enough to rip around corners at a speed that cops would not like. If it is cooler, say 45 or 50 and you try to corner at the same speed as the warm day you could easily end up facing the wrong direction before you know it or under steer like crazy straight into a curb or worse traffic. Here in Montana the mornings are in the 40's to 50's in the summer so at the beginning of an autocross I have to be very careful but by the time noon comes around it in the 80's or higher and I can let it rip!

I auto-crossed a 240 with a 3.1 L6 in Emod for years and another in FP with a 2.8. The stroker car was my friends and the 2.8 is mine. We built both our cars to be street cars and autox/track cars with full interiors and a roll bar. Our club rents a course in Helena MT that was built for training the HWP. The track can be configured in many ways and has a straight long enough it is used as a 1/8 drag strip. I have driven the track configured tight enough to be considered an autox event and other times configured to be more like a track day (time trial?) with higher speeds. Both of our cars are competitive with C5 zo6's and newer (2004) 911's both stock and running DOT autox tires on both configurations. I have had a few fast times of the day awards with the stroker car. We loose time in braking compared to the other modern cars but the light weight makes up the difference in cornering especially in the slalom (we use 100' spacing for the slalom). Our cars have spherical bushings, 250/225 rear and front springs, Tokico 5 ways, sway bars, stock brakes (after market pads), front and rear tower braces, cantilever slicks and alignments for autocrossing. Not very expensive at all but effective. The trade off is too much body roll from the soft springs and poor braking on the track and a hard ride (5 ways help) on the street and we have to watch out for driveways and the tires wear fast. The brakes would never work for repetitive laps (heat) but for one lap at a time they are ok. A real e-mod or f-prepared car would kill us but against very potent stock cars they hold there own. I did go against a new C6 with DOT tires in the 3.1 zcar, I stayed about .5 seconds behind him all season, I would have to do more to the car to get there. We have the power but not the suspension and brakes. Not being able to put an integrated roll cage in the cars (head safety on the street) really holds us back compared to real race cars. 240's can be very good handling cars and can have some of both worlds but not the best of both. And after the race I would rather drive the C5 or 911 home on the 120 mile drive, Z's are loud and tiresome great around town, not for long distances.

Why do you need to go 140+, are you on a track? If you are there are plenty of track tires in the 14" size.

A narrower but stickier tire is better. The 20mm difference is not that much and R compound tires are usually much stickier than a street tire.

If it is a 4:70 and an lsd then it could be an r190 not 180. They look very similar in size, if you are not familiar with them you could easily think it is an r180. The 190's were a competition item (in the states) with either a 2 or 4 pinion gear lsd diff, the 4 pinion are stronger and worth more. I do not know how much they are worth, parts are hard to find and a 4:70 is going to be mostly desired by racers, it is too low for the streets. So if you are going to sell it you have a pretty small market. I have a 4:44 r190 in my car with a zx trans, I would not go any lower and could go a little higher idealy, it is good around town but on the highway it is a little low, 3500 rpm @75.

Search! Search "stroker" or "3.1" or "3.0" ect... and you will find more than you can read in one day. btw the crank is from a diesel Maxima (search that too).

Yes they use the same bushings.

This is my 240 with azc springs which lowered the car about 1.5", I was running 195/60/14's so the diameter was pretty small (23.2") The wheels are 14x7 -12 offset.

If your car has the stock motor you probably have enough low end grunt to leave the car in second gear. It will help with traction with out an LSD and slicks and your driving will be smoother. It might feel slower but often feeling slower is really faster in the end. We run between 4 and 6 runs during an autox depending on turn out and time. If I am going to experiment with a new technique I do it towards the later runs. That way I have the course memorized and I can compare the new driving style to my standard style and time differences should be from the driving not learning the course. Before I modified my car I almost never went to first and it worked very well.

Thanks for the info Jon. That was exactly what I needed to see. The diff is from a Skyline. I think I am safe on the R&P gears, the patter is not all that weird after all compared to some of the illustrations. I think new bearings and a Kaaz or Cusco are in order now. Thanks again.

I have an r200 (long nose) 4:38. I got it from a guy who originally got it from Arizona Zcar a while back when he was selling JDM r200's. Anyway when I got it it whined pretty bad. I have not used the 4:38 for a few years. I have no idea how long the diff was used in that condition, I put about 50 miles on it and gave up on it. I would like to put it back together with new bearings, lsd, a total rebuild. The ring and pinion have a wear pattern on them that is visible and on the pinion appears to be not in the right area. Is it possible the pattern is too engraved into the gears for them to be set up properly. I can feel the pattern with my finger tips, no dips or gouges or anything like that just a very smooth area where the gears contacted and not as smooth where they did not. How can a person tell if the gears are too worn to be used? Thanks for any info.

What color are those. They look great, I am looking at the rb wheels right now and I cannot decide on the color, yours look like the hyper black. Are they?

You might need a grit between the 220 and 1000. You need to get rid of the marks by the 220 with something more like 600 then to the 1000 and so on. It is just like finishing an instrument. I use smaller jumps. I start with 220 then to a 400 to 600 and so on ending with 1500 and then a final buffing wax. It is a lot of work but in the end your finish will be beautiful. You can get the swirls out with the 1000 but it will probably be faster going back with a courser grit first like a 600.

Do a search and you can find tons of info on this subject. The bolt pattern is 4X114.3 or 4.5" The offset for zg's depends on the width of the wheel. With the stock suspension stay at 4.5" of back space or less. I would run a -19 offset on a 8.5-9.5" wheel. Smaller than 8.5" and flares are kinda pointless. You can run a spacer to "fill out" the wheel well too.

you will need flares. The tires will go beyond the fender past the point of rolling the lip. Your wheels will have a pretty large - offset.

http://forums.hybridz.org/showthread.php?t=123538 This thread might help, the wheels are 15 x 8's but you should get the idea of the spacing needed. The +4 or +12 offset should both be good, using a spacer with the +12 gives better fitment options.

I have run the 15x9x23 Goodyear cantilever slicks for years now. They are the R250 compound. They fit the car without flares on 15x7 wheels with a -12 offset. The clearance is very tight and I could not go any lower than the AZC springs (which are too soft for the compound) that I run. I have a localy competitive FP z with a full interior that weighs 2300 lbs but I could never compete in a larger event than the local level. I have Paxed a few events though. I have also been on 2 wheel a couple of times and it scares the hell out of me. I am currently working on a dedicated racer but $ is tight so until then.... You could go into XP with the 3.1 motor the weight is calculated on the engine size but you would still need to cut the body and gut the car, ect.

Last I checked the min weight in FP was 2100 with a 2.8L (.75 X the displacement). 2200 if you go with oversized wheels (over 10" wide or 16" in diameter(100 lbs penalty)) which works out well if you can not get the car down enough in weight.

The camber bushings are not so much for gaining or decreasing lots of camber like a set of camber plates. They do not have very much adjustability. I have them on my car, I used them as a poor man's way of getting toe in on the rear wheels (1/8") and some extra camber (.75%). There is no problem with being streetable but they do transmit road noise far more than the stock bushings as well as more shock from expansion joints and such but I also have an ABS steering couplier too which transmits every thing, but you are more connected with the car as far as feeling the road. You might be able to get + or - 1 degree of camber with the bushings. If you are lowering your car then you will gain - camber that way too, you might put some of the camber back with the bushings. I would not worry about the tire wear, if you are into cornering then the -camber will help decrease the wear on the outside of the tires, if it is set right the wear will be even across the tire width. If you have - camber and you are doing lots of burn outs you will wear the inside of the tire. No mater what if you are driving hard do not expect the tires to last long anyway.

If you go with the coilovers you would not have to section the strut tubes since you are giong up not down thus saving instalation time and headaches. Seems like the way to go to me and you get a little more room to the inside for wider tires/wheels.

15x7 with +13 offset is a 4.5" back space. It will fit. The ZX can take more backspace than the Z could but the 4.5 BS would fit a z too.