JMortensen

It's not the headroom that's the problem. It's the X in the main hoop. Even if you put a bent shoulder bar in like I did, the bottom part of that X will preclude the base of the seat from sliding back far enough.

You'll be alright then. You just won't be able to let your taller friends drive.

Tons of pics here or on facebook. www.facebook.com/Jon.E.Mortensen

How tall are you Jessie? Cage looks very nice, but looks like you might not have enough driver's seat clearance for someone 6' tall.

That's the regular LSD R200. The Nismo one has the shallower ramps. Yours will have the big spacer in it, so for Savage42's threads about extra clutches if you want to upgrade it.

Yeah, I think it's the C6 pan that is shallower than the LS1 pan but doesn't have the batwings.

I'm using a Kevco pan. I made mine shallow. Probably too shallow. I was concerned about the height to the xmember. When I bolted it up I found that the xmember and the trans were both about an inch lower than the bottom of the pan. Still has 5.5 qt capacity, trap door baffles, and remote oil cooler fittings (which I plumbed an accusump into). Only had mine out once to an autox, just got it running in October. I have a big oil pressure light and it never came on, FWIW. I believe the LS2 Vette pan is the shallowest of the stock pans FWIW.

Don't need 6061 either. Get whatever is cheapest.

Kinda like this shot:

Head is not junk. Could weld and fix. I read and was told not to expose anything more than the edge of the fire ring, but don't know if that is passable or not. If you're notching the block to match, you'll have a bit of gasket sticking out which may cost .0000267 hp.

Do you have a cage? Weld a nut to your cage and use that for the ground. Nice, solid metal. PM me your address and I'll send you some steel 1/4-20 nuts. I can't use them.

Camber gain won't be helped. Look at 74_5.0L_Z's sticky in the BWSC forum and he graphs out the camber curve. It's really linear. Have no idea if the bumpsteer will help in the ruts. Suspect not.

JTR is still around. Someone could just ask them how they came up with that 3/4" up and 1/4" out spec. I feel like I've repeated this here 100x, but for my car the difference before and after moving the pivot was night and day. There was one particular turn on one particular track that was making my car do an emergency lane change style swerve as I went over a bump. Also was sawing at the wheel a lot in sweepers. After moving the pivot up 7/16", the swerve was gone completely and the sawing at the wheel much diminished. It only did that swerve on that one corner, and the sawing at the wheel was only at the limit so this is one of those things I'd call a wasted of time for most people, but for racing was worth it.

Yes. A third is to raise or lower the rack. I have a slotted xmember with the LCA moved as high as possible with an aftermarket rack that was raised 3/4" with spacers and the tie rods spaced down to minimize the bump steer.

HF one works, although you can't buy rivnuts from them anymore, so once you run out, you'll have to get them from somewhere else. You can buy nuts from mcmaster.com. The steel ones are impossible to use with the HF pop rivet style tool, but the AL ones work great.

There are various recommendations. I think JTR says up 3/4 and out 1/4. I slotted the xmember and then moved the pivot up until the bumpsteer was minimized and that was more like 7/16" in my case. YMMV.

The cam swap is easy. I have the 5.3 in my 2006 GMC and it is done at 5500 rpm. If take the time to swap it even if you don't go bigger. Might want to check if you would need to upgrade the springs too. Not sure on that.

Nice, realistic expectations and looks like a good car to start with. Are you doing anything to the motor? Rated 310bhp stock, cam can bump that up quite a bit with no problems and the swap is easy. I used a 220/224 .581 on my L33. Haven't dyno'd mine but seems like should be in the 325-350 whp range based on what I've read online.

I'd suggest you do an all in one digital dash. That's what Id do if I could have a do-over. Mine (there is a wideband in the far right hole now):

Here is the link: https://www.linkedin.com/pulse/how-do-motorsport-ground-effect-diffusers-work-willem-toet This picture is a very nice long time average (allowing the fluid to dry well while running the wind tunnel). This picture shows a little better just how disturbed the flow has become. It probably comes from a slightly lower ride height than the previous picture. This change of flow state is significant and results in aerodynamic “hysteresis”. The two vortices hang on fairly well on the way down but, once burst, you have to come back up to a higher ride height than the burst ride to get the flow back into a nearly “symmetrical” state. The fact that burst and re-creation happen at different heights is what we call the hysteresis. This is why the plot of downforce showed two lines – they are for lowering and for raising the diffuser. Clearly drivers will hate the feel of the car if you allow it to get to these areas of performance change. Continuing to reduce ride height further, leads to reducing energy and attachment of the flow and ultimately to complete separation over the entire width of the inlet of the diffuser. Now the next interesting detail..... Here you can see that low angle diffusers don’t reach the same level of performance as those with higher angles (within the range tested). Once a critical level is reached the higher angle diffusers achieve the same downforce (at different heights). You can’t extend this to silly angles – we have tried! What’s interesting is that the highest angle tested has the largest ride height range at max performance. Those at slightly lower expansion angles fall away more as ride height is increased from the peak (remember 1% is a lot). Now why might that be? Now I’m not going to give away everything I know but one mechanism is this. If a body (or a large part of one) has substantial ground clearance then the chances are that there is air below that body which is relatively undisturbed. If true, then the higher the body, the more air is sitting there not being “used”. Conventional flow expansion in two dimensions is not going to take advantage of that energy (not “all” of it anyway). I often talk about how much energy remains in the air. Now the truth is that the car is moving and the air is (relatively) still so what I’m really talking about is relative energy given the velocity of the car. It’s just easier to think of the air moving for an old man who’s done years of work in a wind tunnel J. The vortices rolling up under the diffuser take high energy air from the outside of the body and introduce it into the diffuser but they also take high energy air from below the level of the body and mix it into the body of airflow that is expanding under the diffuser. That’s one mechanism that allows diffusers to remain attached even at high angles of attack. In Formula 1 diffusers are expanded both in side view and in plan view. This is in part because the height limit imposed by regulation is well below the aerodynamic optimum. There is still a positive impact on pressures and hence forces on the flat part of the floor. The trend towards running ever higher rear ride heights in Formula 1 will be in part because the entire floor can become a diffuser, in part because the teams have learned how to use vorticity to take advantage of all that air that otherwise passes under the car almost “unused”. If your diffuser or floor is wide, then there may be energy in the air inboard of the outer vortices which is not used. Image shows a section through a hillclimb car which I can show because it is my image. Even though this is not a conventional diffuser, you can see the vortices on the outboard parts of the floor section. The colours represent total pressure (energy) and the lines (line integrated convolution for the CFD techies) show airflow directions in the plane of the shot which is a cross section of the car near rear axle centreline. There is a lot of high energy air here not being “worked” yet and in a way the height won’t allow a single vortex to engage all of that air – a vortex has to be relatively circular in cross section. If you add an additional fence or strake (a vortex generator of any design really) in each side of the floor it is possible to roll up two more vortices which take advantage of that airflow energy to create downforce. This clearly isn’t an optimised design yet but it serves the purpose of showing what might be done. If I see high energy air exiting the floor of the car (at the most critical low ride heights), I look to find a way of using it. So, hopefully, this explains what fences in the middle of a diffuser do (some part of their function in any case). For additional reading there is a decent section on diffusers in Joe Katz’ book “Race Car Aerodynamics”. I think that has to do for one (monster) post – I’ll cover some other important aspects about diffusers in other posts (oh yes, there is much more!). Still here? WOW - I'm impressed you could stay awake! I love this stuff but it really is for aero nuts like me. For my other posts see :- https://www.linkedin.com/today/author/187006218

He is not on the forums that much. I will tell you that when I shut down my diff parts biz I talked to him at length several times about the CV binding issues. I sent him the technical drawings for my shorter Z31 shafts that I was making and he continued to make them. He is well aware of the CV binding issue. His 930 kit is something that I tried to get done to no avail, and we talked at length about that as well, and he incorporated the design changes that we talked about, which were specifically to allow for more plunge, into his design. If he says it fits S30s, I wouldn't doubt it.

Joe is a racer who preps mostly British cars: http://www.chequeredflagracing.net/ I would say he's a car guy. 930 CVs and shafts are not something new, so I don't know what part of that needs "proving". If they're using 300M joints, shafts, and stub axles, that's going to be as strong as they get too. As for the shafts bottoming, the 930 CVs have a lot of plunge depth. The stock Z31 shafts have about an inch and a quarter of movement as I recall. The 930 style probably has that much on each joint. Since this kit is only available for the R200, the difference in length between 240 and 280 chassis isn't a problem at all. Just put the shaft length in the middle and there will be more than enough plunge to compensate either way.

The problem with DSS's kit is it bolts to the stock companion flange and doesn't replace the stub axle. I know they advertise when they do use 300M, so I guess they're not in this application. DSS makes good parts, so I'm sure their CV axles are just fine, but they're evidently not using the strongest material, and they're missing the stub axle, so it's incomplete. Joe, congrats on getting that kit together. That's a kick ass kit you have there.

I think zero lift would be great, but that's not likely to be what you'll have.

I dunno. I think I'd want level or rake. Screw the drag, I want the front on the ground. Seen this, Keith? https://youtu.be/D59x_2PyUcc?t=8m7s