260DET

Nice work, it will add a bit of down force, no doubt.

Decided to do it, will make some VG's out of aluminium angle using the Mitsubishi 'delta wing' pattern and pop rivet them to the undertray. Will take some pics when its done, if I remember

When the capacity of semi trailing rear suspension is being discussed I always throw in this BMW video and will keep doing so until people say, 'not that bloody video again!' BMW did a lot of work on their semi trailing design, including changing the sweep angle, and Prodrive who prepared that particular car are not amateurs. It can be seen that there is a fair bit of suspension movement on that undulating piece of road, note also the amount of rubber laid down on some corner exits. I suspect due to a lot of toe in which as we know helps stability. Anyway, enough from me, going to look at that video, again

From a reading of McBeath's book Competition Car Aerodynamics it seems that the vortices created by VG's may inherantly lower air pressure slightly but this is not absolutely clear. However given that VG's are used on the top of aircraft wings I'm going to assume that they at least do not increase air pressure. What VG's will do is control air direction so this should assist in directing air along the length of the undertray, rather than have it spill off to the sides. Strakes would do the same thing but with them ground clearance becomes a problem whereas effective VG's can be just 15-25mm high. As Jon said, race car bottoms may be flat due to rules and, I guess, a lack of ground clearance given that bottoming out is not uncommon. Anyway if anyone can see a problem with the above comments please fire away.

Am in the process of making an aluminium front undertray for the project Z and was thinking about getting some of those stick on vortex generators to attach to the underside. The undertray runs from the front of the spoiler back to the engine Xmember, its a bit over one meter long and 670mm wide. It slopes down a bit from front to back but not much so the airflow under it should remain attached. In that situation its my understanding that VG's should reduce air pressure but I'm not sure. For practical reasons the VG's would have to be mounted ~200mm back from the front but I can't see this as a problem as far as results are concerned. So what is the opinion of the aero learned forum members? The rest of you may comment as well

Have heard that Nissan changed the semi trailing arm sweep angle, resulting in less camber change for the same amount of movement. Have not checked this myself though but if its so its a plus for a performance application.

If the car is in roll then its turning in a corner. My simple mind tells me that ideally in a turn both wheels should lean into the corner ie the inner wheel should have positive camber the outer negative. So my answer to the question is 'no', or perhaps more accurately, the question is irrelevant.

At last, yeay, an improved two seat S130 looking like a S130 should, just a matter of waiting.......and waiting......for one to turn up. Very nice, can't say here that it looks better than any S30 but

Is that finish what's called Shadow Chrome? Anyway those wheels look excellent and are not that heavy for that size, not light, but there are plenty heavier.

Thats what I was thinking, extending the airdam and lip right across the front. Alternatively the front could smoothly curve around to meet the wheel well openings, like a lot of modern cars are shaped there, as much as possible anyway. The resulting airflow would help extract air from inside the wheel wells which aids brake cooling too.

You had the same problem I encountered, front spoiler not wide enough to cover the front of the tyres. Started to make a mould for a wider spoiler but then sold the car. Your solution works if it is a bit blunt and unaerodynamic looking. Provision for front brake ducts? On the IC pipe routing, I assume it runs through holes cut in the inner guards.

Of course with strut front suspension there is the same camber change problem that you'll get with a semi trailing rear. I can't comment on your camber change/travel ratio question except to suggest that perhaps, and only perhaps, the amount of camber change at the front may be relevant to what would be an aiming point for the rear. Another way to look at it would be to ensure that at all times there is toe in at the rear, then setup the rest with that in mind. Don't know about you but a nice stable predictable rear end is a very important asset, perhaps more important than always getting maximum power down. Afterall, it no going to be a straightline (drag) car is it

Yeh I did have a bookmarked US private BMW site that had tech info on the competition spec rear end but can't find it now. Bit of a google should turn it up though. Z31 rear end may be worth checking out too, I believe the sweep angle was altered on it to give less camber change, compared with the S130. From the research that I did a well setup semi trailing arm suspension will give excellent power down on corner exit, better than the strut rear end on the S30 for example. The video I linked above is worth a good look. That BM rockets out of corners although it is laying rubber on a lot of the exits. A bit of squat can help power down, the Nissan multilink rear end on my project has been tilted forward to nullify anti squat for that very purpose.

This video shows what a rear semi trailing arm suspension can do in the real world of competition, if you are prepared to do the homework and spend the $. Which 99.9% of S130 owners are apparently not, tightarses.

A good SR20DET will be fine as will the rest of a good S30. With a few mods. Go for it.

Work on a Fairlady theme, that can be relevant yet different if thats what you want. Maybe a sort of sexier Rolls Royce nekkid lady thing

I'll be using ~1.3mm thick alumimium to make an undertray, may get it ribbed, with proper support that should be OK. For smaller items that thickness should be all you need providing the items are properly attached.

Just an observation. Once you start seriously modding its going to be contra to some damm thing, thats the situation in AU with the fun police we have here. What I will say is don't get 'your' engineer involved in every little thing that you are doing, look at the big picture and aim to basically comply with what is obvious. Get the message? With the S130 I checked out the basics then went ahead with the mods then got an engineer in at the end, no problems. Presentation and attention to detail helps give the right impression, too many 'modders' do rough work that attracts attention for all the wrong reasons.

You would do better for less in the US, S130's in decent shape bring good money in Japan. Although most of them are full of rust.

Well you could try another hobby, like hookers and coke. Only thing is with the latter you may end up with your health in bad shape, as well as the finances

Yeh Nissan should have fixed that, they have used the same one since the S30 days. There is a Nismo one available though, made of unbrokenum or something.

Bolt on ones are adaptors not spacers. Its an important distinction because Porsche for one use adaptors to vary track. I'd ask the engineer again, they are not always right first time. Oh and by the way, little 7" wide wheels are gay

Yeh I've seen them around that offset for sale, Skyline wheels. Can't recall which ones in particular but look on SAU for a start, here http://www.skylinesaustralia.com/forums/Sale-Private-Car-Parts-f12.html

You want to do things the hard way don't you, working off the original front instead of replacing it with a decent aftermarket airdam Anyway the first thing I would do is put deflectors either side to cover the front view of the tyres. They could be made from pieces of aluminium sheet and should reduce drag and improve air extraction through the wheels.

I'm not familiar with the weights but the only worthwhile bolt on front swap that I know of is the Toyota vented. Even that is getting dated as far as current braking standards go, it is not done much anymore as far as I know. The Arizona Z kit seems to be excellent value for money, I know of two kits that have been bought locally to me but not fitted yet.