JMortensen

Considering the fact that his cage didn't tie into the suspension at all, I suppose he needed all of the stock chassis for its stiffness. As far as the aero, what did he have? A box from the dam to the radiator (which he said the guy at the wind tunnel poo pooed), vortex generators, and a spoiler. I think that was it. Maybe a splitter? I don't have VGs but I have a plywood splitter and big spoiler and sheet aluminum box to the rad.

Just as a counter point, I had my 70 set up with L28/ZX 5 speed, R200, Autopower roll bar, Recaros, full carpet with a lot of extra sound deadening mat, and it was 2350, which is supposed to be the curb weight of the later 240s. I think there is a couple hundred pounds in the unibody alone. If you're looking to keep it stock, then you can make the case that the 280 is better because it is more rigid, but I think if you start reinforcing the chassis on either, you can get an equally stiff end result, and miles stiffer than the 240 or 280 chassis as they were delivered. My early 240 now has LS V8, T56, gutted, I think it's a 12 point cage with lots of stiffeners including SFCs and strut tower bars, stitch welded, 15x14 steel rims, huge widebody, FG hood and hatch, Lexan side and rear windows, etc. Weight: 2352. Look at something like Mike Kelly's car which was a 280 with similar amount of cage tubing, LS, T56, F8.8 rear, etc and I want to say his ended up at 2800+.

I think the main advantage is in the pistons. You can get digressive 36mm pistons. In fact I think that's what you get out of the box. 30mm is linear, and you can't swap them out.

30mm gland nuts won't work on 280 housings and 280 housings are a prerequisite for 36mm pistons which is what the 3KGT and BMW run. I've got a set on my car too, but they won't do either of us any good in converting to Bimmer struts.

If you do camber plates and somehow adapted them to stock springs, you'd go down 1.5 and 2.5. If you go coilovers you'll start 1.5 and 2.5 down and then can lower with the spring perches from there. Again, IMO, I'd run the bumpsteer spacer in front to correct roll center and not worry about it in the rear. The rear doesn't have dynamic toe change and camber change is pretty linear, and the roll center will likely be higher than front and above ground, so it's a way-down-the-list thing to do after making camber, caster, and toe adjustable, reducing friction in the bushings, sway bars, better struts, chassis reinforcement, etc. Interestingly on the corner weighting, I recently listened to one of Ross Bentley's podcasts I think it was, and they were talking about the relative advantages of diagonal corner weights vs front corner weights, and the guy he was talking to was saying that having the front corner weights even was more important that getting the diagonals even, as this means less likelihood of locking up a tire under braking. First time I had heard that, and it would imply that moving the battery to the back is probably counterproductive on a Z.

Gland nut is an issue as is converting it to double adjustable, which IIRC requires remote reservoirs. I don't believe you can buy them DA from Bilstein, have to buy the reservoir, weld on the fitting and DIY. Sure would be nice to find an easier solution...

Be sure to post what you do on the Bilsteins. I've been looking at modifying 3000GT Bilsteins. Others have done it in S14s, but it's a big PITA and I haven't done it for that reason. If there is an easier to work BMW solution, I'd love to see it and I'm sure I'm not alone. Best of luck!

The issue with lowering the car and altering the geometry in the front has mostly to do with bumpsteer. The camber curve is very consistent throughout the travel. The caster curve is affected, but that's minor. The bumpsteer curve on the Z is crappy out of the box. You can run the bumpsteer spacers to get it back to where it was (crappy) or you can make it adjustable and minimize it. You can do this with a bumpsteer spacer kit from a vendor like Apex Engineered, or you can drill out the steer knuckles and run shims to fix. Bumpsteer shims are commonly available circle track parts. FWIW I do run bumpsteer spacers to help with the front roll center and have the bumpsteer adjusted with the shims to counter both issues. https://www.apexengineered.com/store/p11/Front_Tie_Rod_Kit.html http://www.colemanracing.com/Bump-Steer-Bushing-Kit-P4444.aspx As it is the roll center in the rear is quite a bit higher than the front and I can tell you from personal experience with a low race car that even very low, the rear roll center is still above ground and higher than the front roll center, which are, generally speaking, the things you want. You can weld a new pin tube under the stock one, Ben Cort did that on his autocross car, and Terry Oxandale modified the bottom of the strut housing to make it longer to raise the rear roll center higher, but it isn't the first thing that I'd be worried about. It's pretty far down the list of things to do IMO. 2 way Bilstein struts are not low dollar. They are very good, but there isn't a bolt on option for them for the Z, so you'll be fabricating to get them on your car. If you want a low dollar solution, there are weld on adjustable struts that are not as good from vendors like Tein and BC Racing. They run ~$1000 or so for the set of 4, and you get coilovers in the process. Be careful sectioning the rear struts on a 280. The tubes are longer and the top insulator is taller in the rear of a 280 than the front. You can just get a 240 or 280 front insulator and run that on top of your stock 280 strut and that drops it down an inch with no sectioning required. If you run camber plates front and back, that accomplishes the same thing but you'll drop the car roughly 1.5" front and 2.5" rear. If you section the rear strut tubes and change out the strut top, you'll have trouble getting the rear of the car high enough. You can literally set the frame of the car on the ground and still have several inches of suspension travel left if you screw this up.

The turbo is bolted directly to the head on that EcoBoost motor, so that's going to make exhaust pretty simple I think. It might also make upgrading the turbo more difficult. Not sure what kind of power you are after, Richard, but here's a vid where they did intake/exhaust/tune on a Mustang and gained 113 hp and 96 ft/lbs:

Yep.

No quality control? How long have these been for sale? Since Ross was selling them at Modern Motorsports, maybe 15 years now? How many have had this problem? Sheesh.

That's the old 2.3L. Heavier than a V8, BTW. I'm thinking the OP is talking about the EcoBoost 4, which makes 310whp out of the box. I am biased because the worst car I've owned was an NA 2.3 Mustang, but I sure wouldn't go that way...

Just put the supports off of the hoop on the sides, they'll fit in around the hatch window. Mine go from the sides of the hoop just below the bends to the top of the strut towers. That one shown above is terrible. If there is a fore/aft load on the main hoop if the car rolls, there is almost no support for it. Would fold like a mousetrap.

If you're planning any aero mods in the back skip it, as it creates massive flow separation and lift. If you check the windtunnel testing info in the FAQ, you can see it has the highest rear lift number of any of the tests. Makes me wonder what people are thinking when they put on the Pantera hatch and a spoiler or wing, or the worst combo, roof spoiler with Pantera hatch. It also increased the drag by .2 which is the equivalent of setting the wing that was tested for its highest angle of attack. So you get all the drag of pulling a wing through the air, and quite a bit less than none of the downforce. If you are just in it for looks, it appears to me like there will be plenty of room for a roll bar. Most of us try to get the main hoop of a roll bar as close to the rear fenders as possible and as tight against the map light area as we can, that's still well forward of where the hatch is though.

If you can fab up that tilt frame and the fender liners and all that, you could make a mold and do a FG version. It's tedious but not that difficult.