JMortensen

I'm pretty sure it was John Coffey who told me not to cross the straps. If you should lose one strap, the other will try to straighten and could pull the car part way off the trailer. You have to consider why the one strap would come off, probably something pretty bad is already happening. If you're going to be towing it a lot, you might consider installing hooks on the car and trailer front and back. I got the typical racer look hooks and modded them a bit to make stronger and I'm towing with the car attached to those. Most of the ones in the rear are just a flat plate bent at a 90 degree angle and the loop is horizontal. When you pull on it it's going to stress the bend, so I got Bryan at zccjdm.com to send me a set unbent and unpowdercoated, cut them and welded back together with the loop vertical and then gusseted top and bottom. Kind of a rough copy of what John Coffey had done on the ROD back in the day. I don't recall if you're running bumpers. If you are, especially with 280 bumpers you should be able to make something that will fit under the bumper and not be so obvious. In the back my tilt bed has about a 2' long 1/4" thick diamond plate section so I cut slots in that and hook the straps there. I was going to run D rings but knew that I would lose clearance under the splitter, and tube80z gave me the slot idea. That is a much better way to go if you're tight on clearance. In the front I had some 10,000 lb D rings welded to the tilt bed, as my 110V welder wasn't up to the task. I agree with Keith that winching on is nice and controllable. I have a 3500 lb Harbor Freight winch, works like a charm. Changed the cable out for rope as the cable got snarled pretty much the first time I used it. I can get the car on and off myself and not feel like I'm going to break anything. Mine tilts when the car gets about 1 foot away from the front of the trailer. I'm sure that varies from trailer to trailer.

It is lighter, the gear reduction allows for the use of a smaller motor. Relay, dunno.

If you have trouble getting the car on and off, back the truck onto ramps like you'd buy at the auto parts store to change oil. Really helps. Mine is a tilt bed, Still need the truck on ramps and some 4' boards to get my car on there. A Texas rollback style might do it, but just a 17' tiltbed isn't cutitng it, my race car is very low though. FWIW, my 17' tracks great. Haven't had any issues at all, even pulling my friend's S10 Blazer which was a lot heavier than my Z, obviously.

Without the fences I think you lose a lot of effectiveness with it laid flat. The wind tunnel testing results from the whale tail really surprised me. I wrote Simon McBeath at the time and asked what he thought was causing the downforce that was shown by the whale tail and how it could possibly be as efficient as it was, and that email got posted somewhere on this forum. He basically said he didn't know. I have the feeling - and it sounds like you do too - that the airflow around the back of the car and underneath it is significantly altered by the whale tail. Since the whale tail isn't allowed, I figured hanging that spoiler as far as possible out the back might get some of that effect. My intuition tells me that it's delaying the meeting of the airflow on top and above the car that causes the majority of the change. Since this one is on a hinge I can lay it flat if I wanted to, but I'm thinking that having it still operate at an angle will be more beneficial. Again, intuitively I'm thinking that a spoiler like this at a flatter angle with the wing on top might be the best combo that I can get out of this ruleset. This guy's youtube channel has a bunch of tests with different scale models in water. He doesn't calculate downforce, he looks at the streamlines over the shapes, and uses very simple analyses to evaluate different shapes, spoilers, etc. Things like the circulation of bubbles show wake drag, the overall direction of the flow off the back of the car indicates lift or downforce, etc. When I first saw these I thought it was way too simplified but the more I looked the more I think he's giving good info, even if you can't translate it to XXX lbs downforce at XXX mph. EDIT: Something is going wrong when I'm trying to link to this guy's channel or videos. Search Gray's Garage and you should fine it on youtube.

Sometimes it sucks to be right. Sorry.

Can't have side fences or gurneys like those cars did.

^^^This. With the modest goals the OP has, no need to redo the whole drivetrain.

That's my favorite spoiler, Keith. Looks good on your car too. Not legal for autox though. Needs to be flat for some stupid reason.

Here's the steep angle.

If your goal is only 350 bhp I'd be surprised if you couldn't get that out of the motor that you have with intake/cam/exhaust. I expect my lightly cammed L33 5.3 (better heads, higher compression) to put down somewhere around 325 to the wheels.

I've heard things like 50 lbs downforce at 50 mph, and apparently good drivers with cars that are well sorted can feel the difference at an autox. If it didn't work you wouldn't see it on every high level car that can run one. My class is so open because of the motor swap that I can do a lot on aero (except a diffuser), although I'm not likely to be able to compete with the Lotus that cleans up every year in X Prepared. Mark Belrose runs (ran? he was trying to sell it a few weeks ago) a VARA CP3 car in CA, he has a spoiler. Very fast from what I hear. Thing is built, 50mm carbs, button clutch, etc. Maybe that's the class you're trying to avoid, but it can be done from what I've seen.

Yes, one of Coffey's.

If I can get to a autox test day I'll be able to do back to back runs and see if the angle makes a noticeable difference. I kinda doubt it will. Once I get a wing on there, then I'll use oil to make sure the flow stays attached and adjust the spoiler accordingly.

I finally got around to building a spoiler. Was considering aluminum or Lexan, ended up with 1/4" Lexan, now I think AL might have been the better choice. I made the spoiler adjustable so I can move the supports between 3 holes, 1" apart, and even at the steeper setting an AL spoiler would barely cut any visibility at all. Anyway with some help from FB, I decided to use a piano hinge across the back of the hatch. Could have gone the full width of the car, but sticking with the hatch width is easier from the standpoint of building the thing, so that's what I did. Tom Holt had my trying to cut aluminum rod and thread it to mount the stays. Screwed around with that for an hour or so and said screw it. Went and got some fuel line, pinched the ends and bolted it to the brackets. Much easier, but not as pretty.

I'm running Black pads too on Coffey's recommendation. He said they were OK for autox after the first application. I just dragged the brakes up to the starting line, never had a problem.

That's right, legends spacer is the one. They're adjustable so don't need precise machining. On another forum they were talking about AL vs steel hubs and saying that AL hubs can be a problem because they expand more and change the bearing settings. I think the idea was that you need the bearings loose when cool so that they'll be right when warm. Don't know how you'd go about figuring out the right setting with a spacer, other than to set it while hot, which seems a bit fiddly, working with 300 degree parts and tiny allen wrenches, etc. You can see my gusset here:

Take a shim to your local gear shop. They usually have a wall with 50 different shims for different rear ends. Find one that is close and use it. About 10 years ago there was some discussion about the GM 12 bolt truck diff having very close to the same size. It's really just a placeholder, doesn't need to be an exact fit.

^^^ That makes me think of the uprights on Terry Oxandale's car. Remember he had lengthened the section under the bearing housing in order to raise the rear roll center and had welded an X in that space. Found it:

You're good then.

Isn't VIR super high speed? Shudder to think what happens if that lets go at 160 mph.

Would love to know what broke and where.

Hmm, the 225mm was really easy to drive, even with Mikunis and the relatively big cam. Impressive that you could hold down 400 lb ft without going to a race disk.

Probably a 4 cylinder owner. My friend had a 10lb Tilton on his L18 with 44s with a really stiff Nismo pp and it was difficult to get going. Another friend had a sub 10 lb flywheel in a 1G RX7. You pretty much had to rev it up and drop the clutch. Less torque = harder to drive light flywheel. L28 has a lot of rotating weight already and isn't so torque deficient. I had a 12 lb AZC flywheel with ACT pp and stock disk and it held down my 240ish whp L28 just fine with 3.70 and 3.90 gears. Friend of mine had 10 lb HKS on hers with SUs and 3.90s and later 3.36s and it was also easy to drive. My $.02, skip the puck disk if you don't need the extra capacity. I would suggest ACT's upgraded stock type disk. I can't remember what the friction material is, carbon/kevlar or whatever, with their heavy pp. If you're making too much power for that, I'd go to a 240mm disk before I did the puck disk.

There is not a lot of room for sure. My halo is right up next to the frame around the door and I had to move my seat towards the center otherwise my helmet would interfere and I couldn't hold my head up straight. You might be able to get the seat lower or maybe put the tube lower and bend it out a little farther, but there is a serious issue there either way.

240 frame rails are a lot shorter so if you plugged them onto a 280 rail they wouldn't hit the floor.