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Old 09-03-2016, 08:31 AM   #41 (permalink)
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spyder2 - '00 Toyota MR2 Spyder
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Okay so I got the car, and got a chance to see the underbody while it was on a lift. No pictures, sorry I'll try to include some at some point.

The middle section of the chassis is around 1-2 inches higher than where the rest of the plastic underbody bits sit. Not good, it will take very large amounts of coroplast to fix :/

I may consider buying a full sized mid section brace and using that as a frame to hold a huge coroplast piece on, but they're kind of expensive and the car already has an aluminum "breastplate".

I misspoke about the front radiator vent. Looking at it closely, Toyota made the underbody vent quite aerodynamic. It has slits cut into the plastic blocking off half the area though, which I think I'll cut to free up some flow, while blocking the unruly flow that makes it away from that vent.

The car has a front underbody brace, which can be an attachment point for a sheet of plastic, if I am willing to use zip ties to do it. It's under the car so I guess no one will ever see it...

The rear is missing all the splash shields, which is a little annoying. I am trying to buy a stock splash shield for the engine and transmission, but will cut access holes for the oil drain plug and filter so it doesn't have to come off every single time. The stock engine splash shield is pretty smooth.

I recall 2-3 years ago studying the rear and concluding that an aluminum diffuser would be very easy to make, thus it's in the plans. I was originally getting kind of ambitious and thinking I wanted to bend aluminum sheet to make the strakes that block off the vortices from the rear wheels, but that's probably a bad idea, I'll go with plastic or rubber for easy cutting.

Front grille has TRD foglamps which block off some of the grille, but not efficiently. The mesh pattern plastic protecting the radiator was cut up for the foglamps unfortunately, and the radiator fins are pretty bent from eating 210k miles worth of rocks. I am considering taking the plastic mesh out completely, allowing for a perfectly smooth radiator duct that should be quite efficient. Since the opening is going to be much smaller, I imagine large objects going into the radiator won't be a huge concern...I hope?

Car is dropped I think 1.7" right now. It's a little low for psychological comfort, even though I haven't scraped it yet. Better to raise it a bit though, which will give up some aero due to more tire being exposed.

The rear deck is a little too low to hit the template, and I'm still debating whether I should get the Luxurypart spoiler or the Duraflex Type W spoiler. The Duraflex is really big, but apparently doesn't have good fitment.

VIS dropped the price on its hardtops again, so now I'm getting tempted. I think if I put dark window film onto the rear glass that it might not look so bad...

Racing mirrors are a lot of effort to mount to the car...maybe I can 3d print one?


Last edited by serialk11r; 09-03-2016 at 08:37 AM..
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Old 10-31-2016, 05:05 PM   #42 (permalink)
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Quick update, I haven't had much time to mod the car, since I've been busy with work, selling the FR-S, and cleaning the MR2 up. I did put in a PCV catch can the other day, which will help the O2 sensors and cat stay alive longer, which is some form of "ecomodding" I guess. Wrapped steel wire around normal PVC hose to make DIY cheap vacuum hose heh.

I've taken off the 225 racing tires and put on stock width (185 front 205 rear) street tires, which seem to have improved the rolling resistance a bit, maybe it's just in my head. Drag and lift should be slightly reduced, by how much i don't know.

Today I saw this on Spyderchat:

Someone made a mount plate for racing mirrors and is going to make a batch to sell! I'm going to buy a set with his group buy and put on the Pegasus Racing elliptical club mirrors:
https://www.pegasusautoracing.com/pr...sp?RecID=10133

Based on the shape, I am guessing their Cd is a good bit lower than the blunt rectangle stock mirrors, and they're also smaller too, perhaps just 50% the frontal area. The stalk is much much thinner than the OEM mirror stalk, and the mirror itself looks substantially smaller from pictures. The Cd of the racing mirror itself is perhaps something in the 0.2-0.3 range, from what I recall aerohead saying about mirror shapes. By contrast, the stock mirrors are basically a blunt rectangle, which has a very high Cd, perhaps something like 1 or higher.

If the mirrors constitute 10% of the car's aerodynamic drag, then I would expect these to shave 7% off the total drag of the car. I'm also dropping around 10 lbs of high up weight as well. If the mirrors only add say 6% drag to the car, it would save 4% of the total drag of the car, which still isn't bad. That should be worth 2-3% more freeway mpg.

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Old 11-05-2016, 02:20 PM   #43 (permalink)
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shape / Cd

These are for free-air,but will give an idea.It's important to get them away from the body as well

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