thehelix112

I'm going to disagree with the previous 3 posters here. I (think I) understand how a carby works, I understand how EFI works. At a very theoretical level, if the airflow into the engine is being resisted by anything (like the inertia of the fuel it is being used to move), its velocity will be different than if it is being accelerated (like if 60psi's worth of fuel is being sprayed into it in the directionish of flow). Whether or not this is in anyway significant I will not comment on. Dave

What 0.05 duration on the isky cam jeff? Dave

Race Car Aerodynamics: Designing for Speed - Joseph Katz Competition Car Aerodynamics - Simon McBeath Dave

All good Paul, I would love to bump into some ex-electramotive engineer willing to talk too. Dave

That is not always true OTM. A moderate spoiler on a relatively standard chassis can both reduce drag and increase downforce, as demonstrated by Simon McBeath in his book "Competition Car Aerodynamics". A nascar both reduced drag and increased rear downforce with a rear spoiler. The way this works is the rear spoiler redirects the air upwards off the back of the car which better draws up the air from under the car to fill the large separation region behind the boot. Dave

I agree Justin, HG should not be an issue with studs and correct tuning. Put some detonation detectors on your list, and an upgraded oil pump (TOGA for example). Dave

Nice. Wanna steal me the CAD source file? That'd be awesome. Dave

Could you be more vague please? Dave

Prox, ah that makes sense, I didn't realise. Paul, making 1000hp from any FI SBC isn't exactly pushing it if what I am told is true. (Especially dynojet hp). Who is to say said SBC wouldn't've made 1100hp with a more supercharged/NA type cam? That, and mentioning `trends' is not anything akin to an argument as to why less overlap is required. Do you have any known examples of L6 turbos that have made more power with less overlap? And what exhaust manifold/turbine housings were they running? I assume you have read this article, but if not: http://www.grapeaperacing.com/GrapeApeRacing/tech/turbochargers.pdf Page 6 is where it mentions camshaft selection. I do completely agree though that it is a complicated task to properly design a cam for a turbocharged engine. Good luck with it prox. Dave

The calibration of ABS/DSC/TC/EBD is extremely important. A good friend of mine calibrates the Bosch DSC for Australian release Fords/Holdens. He spends months recalibrating cars between engine changes (V6 to V8). Not only would you need the calibration for the Z's static weight distribution, but for the Z's specific CoG, wheel base, brake calipers front and rear, brake master cylinder, etc which all effect the weight transfer for a given brake pressure. Sure, it might work at a most basic level, but you could also end up spending a lot of effort/$ on a system with unreliable results. Dave

Jon, A performance turbo cam does not have small overlap. Stock turbo cams have small overlap to reduce reversion from restrictive exhaust manifold and turbine housings. Also prox, doesn't Z-Gad run a 2JZ? Not really comparable IMHO. Apples and oranges. What lift/duration works on a 2JZ head might do exactly nothing on a L. And one more thing, comparing advertised duration is next to friggin useless, get specs on 0.05" duration and go from there. I think camshaft design is a very complicated field, add a turbocharger and you've got more complication. The best you can do is listen to other people's experiences and try to work something out from there. FWIW I will be going with something around 240 deg 0.05 dur, and as much lift as I can squeeze into it. This should make max power close to 7000 I believe. Dave

Any prejudice against large wings is almost certainly developed in ignorance. The wider, longer (chord), higher, and further back a wing is the more effective it can be, as we all know. BTW, I think I might be wrong about the outside of the vortex travelling fastest. But I think it might be the inside. Anyone confirm? I could just go look it up, but my chair is way too cumfy. Dave

Hmmm.. whatever the specifics, creating a restriction to the flow at the supercharger is probably not something you want to be doing. I wouldn't mind betting that triangular shape was the source of much research and development at Eaton. If not, it probably should have been. Dave

I know what you mean about busy. Product delivery is in less than 4 weeks and we don't have a prototype yet. Eep. They ARE worlds apart. A z-axis vortex is produced BY flow separation. A x-axis (streamwise) vortex is produced on purpose to DELAY flow separation. Sure they both induce drag, but a x-axis vortex produces drag because it a, has a protruding generator, and b, reduces the static pressure downstream. Given the example we are talking about, this will reduce the pressure immediately after the generator from what it would be without the generator. But x-axis vorticies have an overall reduction in drag as seen by their effect in delaying z-axis vorticies (aka, flow separation). As I said, worlds apart. Regarding the wing, the question becomes whether the wing will have a larger increase in drag than a row of vortex generators, and if so, is the additional benefit of having non-vortex flow running over your rear wing element worth the drag penalty. I would guess it is. It wouldn't surprise me if (as was mentioned somewhere) the wing was developed for the WRC car, then added to the STI for homoglation purposes. Dave

The OUTSIDE of a vortex is where the air is travelling fastest, and thus has the lowest pressure. Your argument sounds logical to me Jon, and now I'm going to go and argue about vorticies and flow separation in this thread http://forums.hybridz.org/showthread.php?t=117165&page=2 Dave

The engine-bay when the conversion was almost finished. Have since added heat shielding and oil catch can. My first time out on the track, also here in video: http://video.google.com/videoplay?docid=-3267393565625239905&q=datsun+240z Me madly trying to fix the rear brake lines. I finished the rear disc conversion exactly 5 seconds before leaving for the track day. When I got there I realised I'd messed up a braided rear line to I had to redo it. I also forgot the bleeding tools so did the track day with the brake pedal on the floor. My first time at the drags, ran 12.834 @ 115MPH on 10psi with an open diff and hard 195 tyres: My err.. custom centre console from alu. Dodgey but it works. The two hoses you see are for my detonation detectors As she sits at the moment, all by her lonesome.

Hey guys, Here are the specs on my car as it stands and a blurb about it at the bottom. Details: Car: Model: 240Z Year: 1973 Colour: BMW Navy Blue (crows feeted to hell) Front bar: Not standard (?) Engine: L28: Block F54, Head P90 Compression: 7.4:1 Cam: Crow #58643 Intake: 212 deg 0.075" dur, 0.480" lift, Exhaust: 210 deg 0.075" dur, 0.495" lift Pistons: Standard Rods: Standard Crank: Standard Displacement: 2753cc (Standard). Oil cooling: Earls thermostat to 235x147x50mm Serck cooler. Balancer: Custom Chris Wood built using BMW Inline 6 balancer. Driveline: Gearbox: FS5W71C S14 SR20DET 5-speed Clutch: 5-puck cerametallic with 1110kg pressure plate Diff: Locked 3.54:1 R180 Driveshafts: Standard *cough* Tailshaft: Shortened with Dana Spicer uni-joints Fuel System: Tank: Standard Lift pump: Carter 110gph Surge: CM510 alloy around 1-2 litres EFI pump: Bosch 044 Fuel feed line: dash-8 (1/2" ID) line Fuel rail: custom Injectors: 460cc N/A S5 RX7 Regulator: Bosch adjustable rising rate Control/Ignition: Type: EFI - fully sequential injection Computer: Autronic SMC v1.99-2 Distributor: Scorcher custom hall-effect Leads: Sorcher 8mm induction Coil: Bosch 716HEC transformer type Ignition Module: Bosch Induction: Manifold: Standard 280zx EFI Throttle body: Ford XF Falcon 65mm Piping: 2.5" stainless Intercooler: ARE 520x300x90 bar and plate Turbocharger: 620hp Garrett GT35R (0.82 turbine housing) Exhaust: Manifold: Custom Ian Rowlerson: stainless, tigged, tuned length, split pulse collector, external wastegate flange External wastegate: Sub-zero 55mm dumping via a 2.5" screamer pipe Exhaust: 3" mandrel bent mild. No mufflers. Ends just behind diff Suspension and Wheels: Springs: Lowered Kings progressive all round Shocks: Gabriel POS, don't ask me why. Sway bars: Whiteline adjustables all round Street Wheels: 15x6.5 Starion Turbo with matt black centres. Street Tyres: 195/60R15 Yokohama AVS Race Wheels: F: 16x7 R: 16x8 Simmons B45 Race Tyres: 225/50R16 Kumho Ecsta V70A Performance: Power: unknown as yet 0-100kph: ~4.8sec Quarter Mile: 12.83 @ 115MPH, 10psi, 195 tyres, open diff. Calder: 1:11.6 Blurb: I have a navy blue 240Z that I purchased from a friend of a friend. Originally brought with blown head-gasket I drove it with the stock L24 and flat-top SUs ( ) until the SUs decided to develop a flatspot from between 1% and 80% throttle. Holding the throttle anywhere inbetween those two resulted in massive overfueling, a black plume of smoke three lanes wide on the freeway, half a rear muffler and a subsequent police detective motivated pull-over. After several 65 mile going 100kph->110kph, clutch, roll down to 100kph, repeat, I sourced a supercharged L28 replacement. After some clutch dramas during the install I drove the car like this for 6 months or so while I gathered together parts for a turbo conversion. Then in early 2005, after breaking the gear selector linkage on the 280z 5-speed in there I took the car off the road to do the conversion. After much saving and what-not I got the car running again in the specs above (after blowing out the countershaft front bearing in the 240Z gearbox I put in the slightly beefier SR20 gearbox which seems to be holding). I have had the car put on hold while I moved to the US, and am working on getting it over here so I can continue its development. These days most of my time is spent wishing it was here and planning/saving for the modifications I have got in mind when that day comes. The car, whilst borderline streetable in its current state, is destined to be a trailer-queen. I know it has a long way to go, so please no flames about being a try-hard racer, I am working on it.

It looks like (from net pics) the M90 pulley is 6-groove v-belt, with 6 grooves. The alternator pulley on the stock dampener is single groove, so one of the two will have to change. Not to mention do you really want to have your boost tied to your coolant flow? I would suggest leaving the alternator driving alone, and simply adapting a new pulley onto the front of the dampener. That is how mine worked when I was running a small SC14 supercharger. I am not sure on the specifics of the output slots, but I'll assume they are the openings in the housing where the air gets expelled? If so, adding any restriction between the supercharger and valves simply means there is more resistance to the supercharger as it tries to push the volume of air that it is geared to. If this restriction is too great it will just snap the belt, or in your case, the belt will slip. It will however make the air come out faster, but I think there will be less of it. You want as much air as is possible as pressure in the inlet tract is developed by more flowing into it than the engine can suck out. Dave

Urgh, I am sorry, I wrote that in a hurry on a break from work. I apologise for sounding so arrogant. That paper has loads of great information, thanks for the link. And apparently I didn't know that another term for `longitudinal vorticies' is `streamwise vorticies'. Dave

You mean this paper: http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf I've already read it. I believe I understand how and why vortex generators work, not only in the evo's application, but in general. Dave

Aesthetically it looks quite nice.. aerodynamically, it looks quite not. Dave

I was actually thinking it'd make a cool print(?) for a t-shirt. I'm going to try to do a 280YZ one soon. If its simple enough I'll even add in my aero-modifications. Dave

Geordie, Yes the angle of attack is relative to the airstream direction. No this does not make the force vectors negligible. It will change the path of the air over a wing (the point at which it seperates/stalls etc) but it will not affect the direction of the force the wing generates which I think(?) is generally approximated as perpendicular to the chord line. There are no dumb questions. Dave

289, Not entirely sure, I've never done glass etching. I've never done any art at all before. Sparky, She put the kit together herself just from bits and pieces. Basically some spray cans, a stencil cutting tool (kinda like a soldering iron with a really thin hot tip), some stencil sheets (translucent plastic that the tool can cut), and some canvases. Dave

Logan, A typical vortex generator creates vorticies (two) about the longitudinal (X) axis. The turbulent (as they are include a forwards component, constituting reversion) vorticies you mention are about the vertical (Z) axis. They are worlds apart. Longitudinal vorticies do not involve any reversion, hence I don't think of them as being turbulent. All they are is a flow that has a rotational component. As for the wing, I am not talking about the wing stalling, I am talking about as it is on a relatively high angle of attack, its resultant force vector will be back and up. The backwards component is drag, and the upwards component is lift. The question is whether this force vector has a larger or smaller impact on the vehicle as a whole, than the resulting increase in the rear wing's downwards and backwards vector, and decrease in the rear window's backwards vector. Hope that makes sense. Also, what size wind-tunnel do you have access to? Full-scale? Dave