Downforce Comparison.
actually i agree a well designed undertray is important to a smooth performing sportscar. but if i remember correctly you've been advocating your undertray-less evo running so well all these years haven't u?
Yes I have been advocating that. As I have made perfectly clear I absolutely HATE the undertrays. HATE them. The factory piece is a complete pain the *** to take off and tieing the cars on the dyno with the undertrays are a PITA too. Drop a wrench, bolt or nut and it gets stuck on the undertay and you have to find it, PITA.
My car with no aero ran 9.77 at 148.3. Now I am not willing to use a bigger turbo I am working to find another way to make it go a little faster.
My car with no aero ran 9.77 at 148.3. Now I am not willing to use a bigger turbo I am working to find another way to make it go a little faster.
Originally Posted by Trojan man;
by NO means am I an aero expert, but generally lowering a car reduces the amount of air forced underneath it which reduces the drag. That's about the only part of aerodynamics that makes sense to me. Otherwise I still can't figure out how a lexus ls430 is more aerodynamic than a vette...
I have been working on a complete virtual model of an Evolution a little bit in order to address issues such as this. The problem is the modeling software I started with is not that user friendly and I am not that familiar with it. If I want to use the software I like, I have to remotely log into a server which slows everything down dramatically almost to the point of being worthless. My plan is to make a couple models, one of which I will run in Fluent or another CFD (Computational fluid dynamics) program. We will see but it is not an easy task and I do not have that much time.
Nothere:
I hatchbacks are less aerodynamic than their sedan counterparts. Now by hatchback I mean something like a geo metro, or a vehicle converted to a station wagon (i.e. the evo wagon or Audi Avant). Now what I think you meant and what you described by the Plexiglas from the roof to the spoiler on the evo is a Kammback. Some kammbacks, or so they are sometimes wrongfully described, actually have a steep slope which almost makes it function like a hatchback. A great example of a kammback vehicle is a toyota prius. You are correct in that if you convert a sedan so a kammback, it would become more aerodynamic. I was just trying to correct the term "hatchback" you used in your one post. A true hatchback vehicle would be worse aerodynamically while a kammback design would be better aerodynamically than their sedan counterparts. Not that it matters but here it is.
Nothere:
I hatchbacks are less aerodynamic than their sedan counterparts. Now by hatchback I mean something like a geo metro, or a vehicle converted to a station wagon (i.e. the evo wagon or Audi Avant). Now what I think you meant and what you described by the Plexiglas from the roof to the spoiler on the evo is a Kammback. Some kammbacks, or so they are sometimes wrongfully described, actually have a steep slope which almost makes it function like a hatchback. A great example of a kammback vehicle is a toyota prius. You are correct in that if you convert a sedan so a kammback, it would become more aerodynamic. I was just trying to correct the term "hatchback" you used in your one post. A true hatchback vehicle would be worse aerodynamically while a kammback design would be better aerodynamically than their sedan counterparts. Not that it matters but here it is.
Last edited by topnitroracer; Sep 21, 2007 at 09:09 AM.
David what cd did you find on the VII? Also if someone could rent one of those windtunnels you see in lots of tv ads what would you think it might cost? I remember years ago in Road and Track about a Fiero and comparing the base model to the more sporty with more aero parts and lower stance and the cd dropping from .34 to .30 or something. Is it a fair assumption that the IX or VIII would benefit a similar drop in cd being lower with springs or coilovers? I know that on my 1G it felt like there was a little less throttle required at speed on the highway after I put new spring/shock combo on it. I too am very interested in aero.
David I guess I should have been less lazy and searched for wind tunnel testing. I was just wondering if you could rent a wind tunnel and test various parts. The answer I found was yes you can but its expensive and usually done by aircraft builders and race teams. I did find this link from sportrider comparing bikes. http://www.sportrider.com/tech/146_0106_aero/
and they a quite unaerodynamic with cd like 60 and the windtunnel rents for $1500 an hour! So much for that idea.I still am wondering how much the cd would lower when lowering the EVO?
and they a quite unaerodynamic with cd like 60 and the windtunnel rents for $1500 an hour! So much for that idea.I still am wondering how much the cd would lower when lowering the EVO?
Last edited by PlanoEvo; Sep 22, 2007 at 06:59 AM.
Hey Dave, I have some pics that I found from a previous poster that has drag values for the IX. I think it was a from magazine but I don't have the magazine, just pics from it.
Cd=0.383
https://www.evolutionm.net/forums/sh...d.php?t=250787
Cd=0.383
https://www.evolutionm.net/forums/sh...d.php?t=250787
