thehelix112

I vote sticky too!

20 atmospheres is harder to believe than a 20000hp electric motor? This is NASA, not a high school science project. Dave

http://www.bsmotor.com/turbo/kalkuler.html Plug in the values there, select the TO4-V map, and you can see that at 2.36 PR and 20lb/min (3000rpm) you are well into surge. I don't know what electronics/boost controller you have but you need to set a rpm-dependent map that gradually feeds boost in as rpm rises. I am in the same situation with my GT35, 20psi is the limit until past 4500. Dave

Hey Simon, I would think you're looking to reduce the drag as much as possible. So set front and rear toe to as close to zero as possible. Adjust the handbrake so they're backed off a touch and definitely not sticking. I don't have my milliken & milliken book with me or I'd look up what effect camber has on rolling resistance. It may be worth while leaving any front camber you have on there. I don't know if you have adjustable shocks but I'd be softening up the back as much as you can, letting some air out of the tyres to make the contact patch longer. Depending on how many goes you get I would be experimenting with launch rpm. Go one low, go one high, compare 60' times, work away from the one that was better in both directions until it starts to get crapper. Oh obviously do a nice little burnout, after the other guy, so you're not waiting there for 2 minutes with your rubber cooling down. I am (unhappily) not as familiar with the Motec M48 as I would like to be, but if you have time/inclination you could maybe set up antilag so you can leave the line with boost at your disposal without having to dump @ a relatively high rpm. Best of luck and let us know how it goes. I ran 12.83 @ 115MPH on 10psi with a 2.2 60', open diff and 195 pirelli P400. I expect you'll wipe the better part of a second off that. Dave

For those interested: Reynolds Number (Re) = (pVL)/u p is density, u is viscosity, V is velocity, L is length or a rough size of the model. For air: Re = 67778 VL (units: V m/s, L m) Re = 6300 VL (units: V ft/s, L ft) As others have said to get the same behaviour you have to maintain the reynolds number. So as you can see, if you are decreasing L by a factor of 25, you have to increase V by the same factor to maintain Re. Sorry if that was boring, I just learnt this last night and it helps me to regurgitate it. Dave

Quite right. And assuming I can control all other frictional losses (from 1st post: "gear ratio, tyre, tyre pressure, weather") I should be able to measure the difference in power required to maintain a set velocity, and from this deduce the difference in forces. Would you agree? Others have mentioned that the trick will be in resolution/repeatability, and I quite agree. But we'll see. I'm just wondering if I'm on the wrong track entirely, and hunting for others who have tried this before. Dave

Page 51: http://www.motec.com.au/pdf/MoTeC_Catalog.pdf Is what I'll be using I hope. Dave

Guys, I've been reading a little about aerodynamics lately and was thinking about how one would go about practically measuring drag and lift. I was thinking: for a given AFR ratio, at a given speed, and controlling everything else as much as possible (gear ratio, tyre, tyre pressure, weather), could you get a measure of the energy required from the injector pulse width required? That would give you something of a measurement of how much power/energy is required to move the car at a certain speed. For lift (as in negative), I was thinking you could just have a linear pot (which I hopefully have access to) between the suspension members to measure the height of the car. Controlling the bit of ground you went over and plotting the values against one another should give an indication any additional compression of the springs caused by downforce. Knowing the spring rate then lets you calculate the effective downforce at either end quite readily. Any thoughts? Dave

Not particularly useful to you I know, but: I also brought the manifold pre-fabricated and I also had all sorts of issues getting the wastegate to fit. Dump pipe was relatively easy if a little finiky. Stick with it, you will appreciate it in the end. That thing will support substantially more hp than 90% of manifolds out there. Dave

DETONATION DETECTORS!!!!111one. Dave

Why not just add a 90 deg down on the end of the exhaust? I have a 90 deg down on my exhaust which finished at the end of the diff and I've never smelt anything. Dave

I'm sorry about the delay guys. I'm in Laguna Beach and have been for a couple of months. When I head back to Oz the engine is coming out of the car so I'll take some happy snaps then. Dave

Don't take this the wrong way, but do you have any evidence of that fact bob? Dave

Its like tubgirl, bad, distasteful, full of ****, but you've still gotta see it. Dave

I would also definitely be interested. Anyone going to be purchasing the forged fully counterweighted stroker crank? A cool $5000 or so. Hehe. Dave

Get yourself an IR gun. Measure outside, middle, inside. Middle is hotter, too much air pressure Middle is colder, too little. I'm sure someone else has more detailed instructions but thats the gist as I understand it. Dave

Any idea what car domain site it was from? Looks like a jap/pome/aussie car (RHD) with one helluva rear diffuser. Dave

Austin, I'm in the same boat. Books ordered. Cary, That is what I thought you were talking about, but I just wanted to check. Thanks. Dave

John, Thanks, sorry to appear lazy. With the first two series of pics, I can't really see whether the upwards diffusers leads into an open cavity above the flat underbelly that channels the air down the car? Is that the case? Dave

Is a front diffuser a rising section behind the lowest bit at the front? As seen in this pic: http://www.mulsannescorner.com/diffuser5.jpg Does this function to slow the air down, reducing pressure, at the same time as a high pressure zone exists above/in front? Sorry if thats not too clear, I'm still coming to grips with the majority of these concepts. Dave

6500? With what internals? For what application? With what cams/springs? Too many variables to make any call like that IMHO. Dave

Oh yes, pics please. Just ordered those two books. Just to stir the pot a little (read: threadjack), what are peoples opinions on the 280YZ kit's aerodynamics? Dave

One question though, what are you doing about venting engine bay air? The two mini-cowls you have on either side of the main one are facing the high-pressure zone of the windscreen and I think will not vent much? Dave

Rick, That looks absolutely awesome mate. I am very jealous. Some of the 280YZ examples on the RR webpage don't make me want to buy the kit, but yours and Ted Fishers are absolutely beautiful cars. Top work integrating the headlights too. Love it. Can't wait to see it painted. Dave

Strength. 71C gears are wider than 71A/B. Selector forks and shafts are also beefier. Dave