BQR280Z Posted June 10, 2008 Share Posted June 10, 2008 Here's a shot of the Ford GT diffuser after I narrowed it for the Z. I will cut into the rear valance and set the horns up into the valance. Then carry the stripes through the diffuser. The leading edge will be above the lower edge of the rear control arms and the lower edge of the differential. I know not all the benefits of a true flat bottomed car, but I like it and I think it looks good. Bill Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted June 10, 2008 Share Posted June 10, 2008 I know this is the wind tunnel section but if i had that to put on my car i doubt i would care to much if it worked or not lol Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 10, 2008 Share Posted June 10, 2008 The key to making diffusers actually function is to get the strakes close to the ground. On a street car, that is also likely to get them knocked off, but if you want it functional, put it as low as you dare. Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 10, 2008 Share Posted June 10, 2008 What about having strakes that can swivel up and down? If you hit a bump or goe up a driveway the strakes just swivel up. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 10, 2008 Share Posted June 10, 2008 What about having strakes that can swivel up and down? If you hit a bump or goe up a driveway the strakes just swivel up. Sounds like the ground effects F1 cars from the old days. I don't see why that wouldn't work. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted June 11, 2008 Share Posted June 11, 2008 Urethane rear diffuser anyone? Sounds like there could be a market for one. Is that Wisconson Cheese Yellow? Nice I like it. Let us know how it works and looks. Quote Link to comment Share on other sites More sharing options...
cockerstar Posted June 11, 2008 Share Posted June 11, 2008 Lets see some pictures as soon as you get it mounted! Looking great Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted June 11, 2008 Share Posted June 11, 2008 What about using the rubbery stuff, lawn molding I think it is called, that some people put on the front of their air damns? Quote Link to comment Share on other sites More sharing options...
garvice Posted June 11, 2008 Share Posted June 11, 2008 Damn that is going to be cool Quote Link to comment Share on other sites More sharing options...
BQR280Z Posted June 12, 2008 Author Share Posted June 12, 2008 The color is actually Viper Race Yellow, with white stripes. I put gold pearl in the clear and now for the new paint job it will get diamond dust in the clear also. The new 15 gallon aluminum fuel cell lets me mount things tighter under body than the original tank would have. Thanks for all your comments, I think it is going to look great. I'll post some pics as soon as I get it hung and more when the paint and everything is finished up. Bill Quote Link to comment Share on other sites More sharing options...
BQR280Z Posted June 12, 2008 Author Share Posted June 12, 2008 Here is a shot of it in place, once tucked up into the final mounting place the sheet metal between the strakes will be flush with the bottom of the valance. Matching my stripes through the curved strakes will be a job for my line lasers. Bill Quote Link to comment Share on other sites More sharing options...
bjhines Posted June 13, 2008 Share Posted June 13, 2008 It looks like the middle area needs some aero devices ahead of the diffuser. Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted June 14, 2008 Share Posted June 14, 2008 Well, it looks good and it should do something. I like it. Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted July 22, 2008 Share Posted July 22, 2008 I don't mean to thread jack, but on my WRX, I put a STI diffuser under there and it helps keep the back of the car cleaner and a little more stable. But, I bring this up because the Subaru part is very cheap and might be easy to work with. Here is a picture below Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 22, 2008 Share Posted July 22, 2008 I don't mean to thread jack, but on my WRX, I put a STI diffuser under there and it helps keep the back of the car cleaner and a little more stable. But, I bring this up because the Subaru part is very cheap and might be easy to work with. Here is a picture below How did you measure the effect of the diffuser after installation? Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted July 22, 2008 Share Posted July 22, 2008 How did you measure the effect of the diffuser after installation? By sight and butt dyno. Visually, the back of the car doesn't get as dirty as quickly. I drive the same roads and park in the same spot day in and day out. Also, when I am driving in the rain or snow, the back window and bumper don't pile up with snow like before (without the diffuser). By butt dyno, I used to drive this section of road between LA and Phoenix all the time and there are a couple stretches that I enjoy doing some high speed runs. I noticed that the car's butt feels more planted and doesn't have the wiggly butt effect when the diffuser is on. I did the drive 2 times in 2 weeks, once with, once without. Both days had similar wind conditions and temperatures. Nothing else on the car changed to my knowledge such as suspension settings, tire pressure, or actual hardware. I would assume that Subaru wouldn't add a piece of aero gear to their STI if it didn't do anything. The STI benefits from a complete bottom cover set that goes from front to back, the other impreza models depending on trim level get some or none. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 22, 2008 Share Posted July 22, 2008 By sight and butt dyno. It looks like it's too high off the ground to really have the effect that a diffuser should have, based on the wind tunnel testing that I've read about in Racecar Engineering and elsewhere. I'd like to see some hard numbers from cfd or a wind tunnel to prove it's effectiveness. Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted July 22, 2008 Share Posted July 22, 2008 The ride height of my wagon is a little lower than that of an STI. I would assume that Subaru would engineer their product to be effective at the height at which the car is delivered... but I'm not an aero engineer, so I am just guessing that parts like this aren't installed for the fun of it. For keeping the back of the car a little cleaner from dirt, snow and rain, it is noticable for me. The top of the tailgate where it meets the glass used to collect lots of road grime and dust. Now, that spot is even like the rest of the car. For the stability effects, there is a change once the car gets above 80mph or so. It's not one of those changes like from a really loose rear end to massively planted, you might just notice that the car feels a little more confident. But again, I have no data to back it up, and since the STI was not offered in a wagon for 2006, I can't compare the two... and a sedan comparison is most likely not fair since the STI model has a massive wing, rear vane spoiler and more underbody aero parts. I think if anything, it smoothens the air as it leaves the undercarriage and that should be worth something. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 22, 2008 Share Posted July 22, 2008 I would assume that Subaru would engineer their product to be effective at the height at which the car is delivered... but I'm not an aero engineer, so I am just guessing that parts like this aren't installed for the fun of it. I would assume they would sell anything they can make money on. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 22, 2008 Share Posted July 22, 2008 I would assume they would sell anything they can make money on. Well, they are something that Subaru currently competes with, so there may be something to it. I've heard claims from Mitsubishi/Subaru on their aero testing and the top-end version's slightly better cd/stability from such things. I'll see if I can dig the stuff up. If you'd seen the underside of an STi without it, you might not be quite as doubtful of it's "help". That being said, I know I certainly won't claim to be able to notice a difference on public roads... Quote Link to comment Share on other sites More sharing options...
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