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Thread: Building an Exocet for ST2/3

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    Default Building an Exocet for ST2/3

    Well, we've had the Exocet race chassis since March and have been doing quite a bit of fabrication to prepare the car for a racing career. On Monday we finally set the OCD aside and loaded it into the back of the truck to go to Powdercoating.... then the build will start in earnest. Hope that we can complete it and get some track time in - maybe in August?
    topowdercoat.jpg

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    From experience, the Exocet is slower than a Miata with the same power, despite being much lighter. The suspension geometry and aero issues handicap it. The few fast Exocets have big power and Hoosiers.
    Aero is key for ST2 and ST3 and the Exocet is an aero disaster. Good choice for autocross from an engineering standpoint (emotional attachment notwithstanding), you would be better off with a production unit body based project for ST2 IMO.

    Not trying to troll you, or rain on the parade. Just suggesting you might temper your expectations that may conflict with known data points.

    my .02


    edit: Moti needs to do a tube frame for the Miata rollerskate
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Agree with all the above points, including the tube frame edit.

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    Senior Member fatbillybob's Avatar
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    Not to worry! Your TrackHQ brother here has a fresh LS6 motor that will solve any aero problem a wimpy motor cannot overcome.

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    Senior Member bellwilliam's Avatar
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    Quote Originally Posted by fatbillybob View Post
    Not to worry! Your TrackHQ brother here has a fresh LS6 motor that will solve any aero problem a wimpy motor cannot overcome.
    Moti will spit on your LS6, he is a Ferrari engine guy now !!
    S1 Supermiata - 220whp
    13 Tesla, ma: no engine !!
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    I should also point out that NASA ST is power to weight class. The Exocets only intrinsic advantage over a Miata os the 600lb weight saving. That is lost when you fill out your NASA classing form.
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    Yes, the Achilles heel of the Exocet is its Aero and how much that comes into play is going to be track dependent. Below ~80mph the aero is not going to be that dramatic compared to a stock Miata but the ~800lb weight advantage is substantial. A substantial weight advantage helps acceleration, cornering, and braking. To say that an Exocet is slower than a Miata with the same power is simply a nave assertion. There are going to be a LOT of track configurations where an 800lb weight savings is going to trump poor aero. Another unsubstantiated statement is to assert there are “suspension geometry” issues – a rumor that a less-than-objective person would want to propagate. The reality is that Exomotive got the shock tower heights incorrect (too tall) but a long time ago came out with a simple spacer kit to address the “geometry issues”. If you failed to recognize or correct this issue, I can see why you had a poor experience.
    Like you, I’ve seen very few fast Exocets – in person or otherwise. Most builds are done on a very shoestring budget by persons with no racing experience. (Nothing wrong with that.)

    Finally, you have no clue what we’re using for power – do you?

    Spot us 800lbs and let’s meet at a tight track and we’ll see just how terrible a properly set-up Exocet really is.

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    Senior Member robburgoon's Avatar
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    giphy.gif

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    The Real Captain Slow Red_5's Avatar
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    ^^
    99 Mazda Miata SuperMiata #515 - AKA Sparky SOLD
    '91 Mariner Blue Miata project AKA Napoleon

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    Emillo - I'm really sorry that you didn't possess the skills to make a 13:1 weight to power ratio car get around a track faster than a 18:1 car. As for my own skills, I have no doubts.

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    I should also point out that NASA ST is power to weight class.
    OMG, really!! Holly %$&, we should have really researched this more before committing for this build. The things I learn today.... it is just amazing!

    Hmmmm.... in a power to weight class a 4000lb 400hp car is an equal to a 2000lb 200HP car in getting around a road course?? That advantage just ***poof*** goes away when you fill out the classing form! Amazing.

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    Senior Member fatbillybob's Avatar
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    Well we got a good forum here with lots of guys knowing lots of other guys here in person which includes knowing some of their talents. So before this gets out of hand lets all be cool.

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    BMW Master bawareca's Avatar
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    Quote Originally Posted by CoolTech View Post

    Hmmmm.... in a power to weight class a 4000lb 400hp car is an equal to a 2000lb 200HP car in getting around a road course?? That advantage just ***poof*** goes away when you fill out the classing form! Amazing.
    Well, the 200hp car will have advantage on a tight track and will be a disaster on a fast track. Over 80 mph you need power to go fast and the weight almost does not matter.
    Anyhow, cool project, it will be interesting to see the final product capabilities.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    CoolTech,

    Save the defensiveness and vitriol. The naivete you assess isn't there. We are the folks that brought the shock mounting point flaw to the public and triggered the shock mount extensions that are now optional.
    We have done quite a bit of testing on both an stock power and supercharged Exocet with a wide variety of suspensions and tire setups on a few different tracks.

    Our track experience with Miatas is well documented.

    Their only benefit over a Miata is weight. They suffer in suspension geometry and aerodynamics. Plenty of data points for lap times around the country from Exocets and Miatas that match our own experience.
    Power to weight in NASA is scaled, not fixed. Lighter cars get dinged to make up for their agility. ST2 cars make up their time on the fastest parts of the track vs a lower powered car like an ST4.

    These are facts, not conjecture. Facts that do not support a build with vastly inferior aerodynamics and compromised suspension geometry.

    Get bent out of shape, that's your choice. Again, just suggesting you approach your goals with an open mind. Regardless of the final results, I hope you and your team find it fun and rewarding. Unless you are a pro, that is all the matters in the end.

    In any case, me and everyone else on TrackHQ applaud your commitment to the project.
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    But obviously I just dont get it. -fatbillybob

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    Chest hair required Olitho's Avatar
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    Quote Originally Posted by fatbillybob View Post
    Not to worry! Your TrackHQ brother here has a fresh LS6 motor that will solve any aero problem a wimpy motor cannot overcome.
    Hey! I forgot you had an engine.

    Call me or text me. I might want to buy it.....
    To the right of The Sheriff. Isn't everyone?

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    Emilio - nice post... now you want to take the high road.

    I post the fruits of a lot of our labor and expense and you piss all over it - then you accuse me caustic criticism? Really? And now you speak on behalf of "everyone else on TrackHQ"? If you represent the voice of TrackHQ, I'm seriously out of here. My intent was to CONTRIBUTE to this forum - not to attack and ridicule the projects of others.

    You are one of a few that wants to maintain that the Exocet has a fundamental "suspension geometry" issue - and place this in the same category as the aerodynamic inefficiencies which are relatively well documented. As you know, the Exocet uses the front and rear subframes from the Miata as well as the PPF brace. The suspension (except for the top of the shock) all mount to these subframes. Front track, rear track, a-arm geometry are all identical to the Miata so maybe you can enlighten us as to what is at the root of this devastating suspension geometry issue.

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by bellwilliam View Post
    Moti will spit on your LS6, he is a Ferrari engine guy now !!
    I doubt it, Carl doesn't do el-cheapo V8 Ferraris, he's a Ferrari V12 kinda guy

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by CoolTech View Post
    As you know, the Exocet uses the front and rear subframes from the Miata as well as the PPF brace. The suspension (except for the top of the shock) all mount to these subframes. Front track, rear track, a-arm geometry are all identical to the Miata so maybe you can enlighten us as to what is at the root of this devastating suspension geometry issue.
    CoolTech, the Exocet does use the entire Miata rollerskate, but it's all set up at the wrong ride height.
    Whoever designed the chassis overlooked this very important detail (or made the wrong compromise) and by that designed a serious flaw that you can't really get rid off unless you raise the car / shock towers.
    Last edited by Blackbird; 05-31-2017 at 06:00 PM.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Just adding this for the benefit of those who are not well versed in Miata lingo, this is the "rollerskate".
    The entire suspension / drivetrain can be dropped from and bolted to the chassing as a single unit while connected by a torque arm known as the Power Plant Frame (or in short PPF).




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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    I don't think I ever took the low road. Read my first post with an open mind.
    Please highlight and quote any specific criticism, sarcasm or anything not based on direct personal experience. Quote any attacks on your character.

    If you like, I can quote yours.

    You are angry simply because I don't agree with you and had the temerity to voice it publicly.

    And yes I think I do speak for Thq. You are welcome here, that I can guarantee. Everyone here has shared their bat**** crazy ideas, mistakes and failures. We also share our successes.

    Man up an accept that not everyone will think you are gods gift to driving, or race car engineering.
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    Aside from their cost I never understood why people race them.
    But obviously I just dont get it. -fatbillybob

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