260DET

Could be that a single TB on a plenum makes more torque while individual TB's make more horsepower?

Replacing the rear hatch and glass with a fiberglass and polycarbonate substitute saves heaps. Importantly it is 'high' weight which influences body roll and hence handling. An original 240 bonnet is a lot lighter, too.

All 10mm new, all 9mm minimum except 2/79 - 8/81 @ 8.6mm, in this country.

Dunno about anyone else but I wag school a lot. Now about how revalving the rear shocks to increase the compression damping dramatically improved rear end grip.....................

Yes, black. And if you really want to be fussy a very light coat of flat black. But I wouldn't bother. In fact, for the little difference it makes, any dark colour should be OK unless your engine cooling is extremely, extremely marginal.

With a well tied in roll cage you can use very stiff springs on the track. One advantage in doing so is that you will not need big anti roll bars but you will need the very best shocks. Some Z's successfully use Proflex remote cannister fully adjustable shocks, which are definately not cheap. Very likely you will have to be prepared to play around a bit with your spring rates to get the best front/rear balance. Getting that balance and adjusting the shocks to suit will be the key.

Thanks John, a proper track test will follow so I'll look out for the condition you have mentioned. The effective spring rate at the front is likely to be a bit less than 100% of the actual spring rate due to caster, track and camber changes which have resulted from moving the bottom of the struts out and forward? Hope to get the whole car and it's front and rear axle loads weighed next week so as to put this spring rate thing in perspective.

In what sort of situation is a pitch problem likely to show up, John? On the undulating road test this morning it felt as solid as a rock although on that particular public road it was impossible to push the car anywhere near its apparent limits. Car feels like it would have to be pushed up to at least 150kph through dips etc on a second/third rate road before the suspension performance could be properly evaluated. Shock bump valving has been changed, so that the rears have 25% less than the fronts, if that is relevant.

From memory one or two of the original bearings in my box were Nachi. Providing they are made in Japan they should be OK.

Most of the transmission backlash in my car is due to the stub axles being a bit loose on the gear splines in the R200 diff. Apparently quite common.

I rebuilt a Nissan, not a T5, five speed gearbox recently. A workshop manual will be in my fussy opinion essential although the Nissan manual I used was not the best as to the reassembly sequence. You may need a press to get all the bearings off but basically its a home workshop job. There are a couple of items, circlips and the countershaft front bearing shim, for which several optional thicknesses are available. Can't comment on your kit, mine included the right transmission specification NTN bearings.

One thing you may wish to think about now is what shock inserts (cartridges) you are going to use. Because, if the car is likely to be lowered more later, you will need shorter inserts then. You can put spacers under shorter inserts now and remove them later.

From memory, the book is out on loan, Fred Pughn's book How to Make Your Car Handle says that many cars are designed to have a significant scrub radius but he doesn't say why. Perhaps some scrub radius gives better steering feel?

Here is some data on anti sway bar rates which may be compared with spring rates so as to judge the effect that a sway bar has. The sway bar rates were provided by a contributor to this forum and take into account the leverage factor. To compare various sway bars I have used the Diameter Conversion Chart from http://www.whiteline.com.au. Front : 22mm bar - 268 inch/lbs, 23 mm - 321. Rear : 20mm bar - 86 inch/lbs, 21mm - 105, 22.5 - 139. Using the Diameter Conversion Chart, substituting a 28mm bar for a 22mm will increase the rate by 162%, ie from 268 inch/lbs to 702, if my maths is correct. Which nicely illustrates the huge influence a large sway bar has on suspension rates compared with the spring rate itself. Plus, as johnc indicated, consider the effect of coupling the independant suspension together with any sway bar, particularly a large bar that exceeds the spring rate by several times. To every action there is an equal but opposite reaction applies with a vengance.

Good, I'm going to do it. You seem to think of everything Ross C.

Using the stock first gen strut assy, it appears that the only way to reduce the scrub radius is to use larger diameter wheels/tyres, and/or, relocate the wheel inwards. Yes, the 280ZX strut seems to be better designed in this regard, particularly as it is possible to locate the top of the wheel/tyre under the lower spring perch and so closer to the strut tube. Depending on the diameter of the wheel/tyre of course.

One really good thing about this forum is the comments sometimes made which get the brain thinking. Someone said something about redrilling or slotting the three holes at the top of the body structure itself rather than mess around with adaptor plates or whatever. While my car has adjustable lower control arms for camber and same with the tension rods for castor, it seems like a good idea to relocate the top strut pivot points (insulators) as well for several reasons. On examining the location of the three insulator bolt holes, it seems possible to retain the inner hole location, the hole nearest the engine, and rotate the location of the other two holes towards the back about 20mm. This will both give a bit more castor and negative camber. I can't see any downside to this. Easy to do and the final camber/castor setup can be done using the existing adjustable components. Importantly, whatever extra castor gained means the wheels will have to go forward that little bit less to get 5 degrees, recommended by Johnc I think.

IIRC scrub radius and king pin inclination are related. One problem with a Z with 'outset' front wheels ie wide wheels which are mounted further out from the hub than stock, seems to be the condition of steering kick back when you hit a large bump when turning. Not bump steer which is similar but which can occur when driving straight. Steering kick back seems to be related to a change in scrub radius, whereas bump steer is related to an out of sync front suspension/steering arms situation. Now I'm not clear on any of the above so comment invited.

One thing I learnt the hard way in the wet was to back the Koni rear shock rebound setting right off. Lucky it was on a race track so some embarassment was the only penalty as it happened. A nicely executed 360 onto the infield. 8)

LedFoot, congrats on your sensible approach. Wish I had done the same instead of learning the hard (expensive) way. Can't really answer your question on wheels although the topic has been discussed on this great forum in the past. The fronts are the problem, particularly if you fit four spot calipers which often require the wheel to be moved out to clear. Which can be easily done by using Datsun 240K hubs which will gain about 10mm 'outset'. In which case with 15" wheels the front guards will usually have to be rolled using tyres around 215 X 60 size. Which is what I have done. So you can see that you need to consider any brake upgrade at the same time. A possible brake solution is to use two spot sliding calipers which may not require more outside clearance so you can use stock Z hubs. Let us know what you come up with if you can.

Thats about it LedFoot, except use poly strut bar/tension rod pads. With the sway bars there are several OE choices available which IMHO are all you need, although the heavier aftermarket Superpro brackets are better than the OE ones so you can then use the wider Superpro poly bushes as well.

Testing the car on a wet skid pan facility is a good, safe way of finding out how the car performs in the wet. Plus it is fun and you can refine your driving technique at the same time.