1 2
Snrub
Snrub HalfDork
5/22/19 9:43 a.m.

I noticed Exomotive debuted a prototype Exovette at UTCC. Has anyone heard any information about it? It appears to use a corvette donor vehicle. It can be seen here: https://grassrootsmotorsports.com/news/fastfriday-5-10/ Did anyone at Hyperfest to see it and have any impressions?

tomtomgt356
tomtomgt356 Reader
5/22/19 10:23 a.m.

It is a prototype using the exocet concept but using a C5 Corvette instead of a Miata.

https://m.facebook.com/story.php?story_fbid=1265902690232503&id=223661801123269&fs=1&focus_composer=0

NOHOME
NOHOME UltimaDork
5/22/19 10:31 a.m.

Does it come with a flush handle for the seat? Gonna need one.

 

Pete

spacecadet
spacecadet HalfDork
5/22/19 10:39 a.m.

2100 lbs was the weight of the prototype. Will be a potent package. 

aircooled
aircooled MegaDork
5/22/19 11:05 a.m.

VETTEKART!!

Patrick
Patrick MegaDork
5/22/19 11:12 a.m.

I’m all for it

Rodan
Rodan HalfDork
5/22/19 12:04 p.m.

Oh, yeah... laugh

Keith Tanner
Keith Tanner MegaDork
5/22/19 1:19 p.m.

Warren's been working on that for a while as a personal project, I'm surprised to see it being sold under the Exomotive name. It's a pretty clear extension of the Miata-based concept, because the Vette has a very similar rollerskate.

For a weight reference, the XXXocet we built a few years back using a supercharged Cadillac LSA weighed 2000 lbs. I believe the latest V8 Exocet we built was 1800. So there's about an extra 300 lbs in the Exovette. It would definitely be easier and less expensive to build than a V8 Exocet because it's a single donor. The original Exocet design was intended for an MOT-failed MX-5 with stock size tires and stock power levels, and even with the US redesign (significantly more structural integrity) you do start to get the feeling you're running up against a number of limits when you try to jam a V8 in there. Turbocharging the stock four puts it in a really sweet spot.

There's a significant size difference.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
5/22/19 1:25 p.m.

In reply to Keith Tanner :

That picture makes me want it more. It also makes me wonder if there are any tire clearance issues out to something like a 335. Becasue it looks like you could put ALL the tire on that. 

Keith Tanner
Keith Tanner MegaDork
5/22/19 1:30 p.m.

Tire clearance is one of the problems in the Exocet. That swoopy rear frame will clear a 185, but when you try to put real rubber on there you discover that the tire moves forward under acceleration and hits the frame. The one we most recently built had to use  15x10.5 wheels with a -18 offset, and let's just say you're not going to find those on Tire Rack. Hopefully Warren took this into account on the Exovette - I suspect he did.

accordionfolder
accordionfolder Dork
5/22/19 2:16 p.m.

In reply to Keith Tanner :

Wheel and tire packing in the exocet is so annoying - so limiting. I see some pretty swoopy tubes on the exovette, but I'd hope they accounted for it. Honestly I don't like the proportions of the exovette as much as the exocet. 100% agree with the exocet + mild turbo/super charging or a k20 unit is perfect. Playful, stupid fast on small/medium sized tracks, but not yet too scary for normal humans to drive. I wonder if the exovette would lose some of that fun? Without a full body you're never going to be the absolutely fastest with an exo car's aero disadvantage, but the cost to speed for an average exocet makes it great. Not sure if the c5 based car sweet spot/fiz factor still.

nderwater
nderwater UltimaDork
5/22/19 3:25 p.m.
Keith Tanner said:

There's a significant size difference.

Considering they both have the same powerplant, I'm curious how differently the new car drives with all that extra wheelbase.

Keith Tanner
Keith Tanner MegaDork
5/22/19 8:02 p.m.

A much longer wheelbase and a lower percentage of weight on the front wheels - due to both the engine placement and the transaxle setup. Looks like you sit a little further back in the Exovette so you'll get a bit more feedback from the back end but lose the "car is rotating around the shifter" balance of the Miata. Approximately 300 lbs more weight. I'm going to guess it'll be more comforting on high speed tracks but less nimble on tight ones - although it's possible the weight distribution might claw some of that back. I wonder how the polar moment compares? The Exocet also has a problem with your outboard elbow location, you have to drive with it hanging out of the car or jammed up against your ribcage. The 'vette may have enough room for a more natural position.

I just noticed the pushrod (or pullrod) suspension on the big boy. It could have rising rate suspension which brings in some interesting tuning options. It could also have falling rate suspension but let's hope not.

oldopelguy
oldopelguy UberDork
5/22/19 11:31 p.m.

As a fat guy I welcome our new larger overlords, eh, deathcarts.

Snrub
Snrub HalfDork
5/23/19 8:47 a.m.
Keith Tanner said:

I just noticed the pushrod (or pullrod) suspension on the big boy. It could have rising rate suspension which brings in some interesting tuning options. It could also have falling rate suspension but let's hope not.

Good catch, I missed that! It's obvious, but unexpected! Very cool.

Keith Tanner
Keith Tanner MegaDork
5/23/19 8:57 a.m.
oldopelguy said:

As a fat guy I welcome our new larger overlords, eh, deathcarts.

FYI, you can put a pretty big dude in an Exocet. Bigger than you can in a Miata. But the Exovette is obviously quite a bit wider in the cockpit, look at the space around that seat!

accordionfolder
accordionfolder Dork
5/23/19 9:57 a.m.
Keith Tanner said:

.... The Exocet also has a problem with your outboard elbow location, you have to drive with it hanging out of the car or jammed up against your ribcage. The 'vette may have enough room for a more natural position. ...

Funny - I have my seat pretty far forward so I feel like I have more elbow room in my exocet than my equivalent caged miata I used to run - though getting in is a lot harder with the halo seat in my exo....

I'm excited for more mainstream exo car options - I've seen a few relatively well done home built cars and a LOT of badly done DIY exo cars. Before my first event at their track I emailed NCM about their allowances for exo cars (some tracks are weird about open wheeled cars) and they specifically asked if it was an exocet or home built and quiped that "the ghettocet revolution is here ... and it's terrifying" in regards to the home built cars they see... 

jwagner
jwagner New Reader
5/24/19 11:30 a.m.

The Exocet is a small track monster because it's light and small and agile with good power/weight.  On a short track with a built K20 it runs with the big stuff.  However on a long high speed track the lack of aero becomes a limiting factor and the stuff you could handily pass on a curvy 2 mile track blows by you by the middle of the straight.  250HP and 1550lbs is great power/weight, but with the aerodynamics of a large brick it isn't that fast around a big track.  The Exovette looks to me like a bigger, higher power Exocet that would be better suited for bigger tracks, but that's where the lack of aero becomes a bigger deal relative to power/weight ratio.

I'd really like to see an aero kit for the Exocet.  Something like an integrated front wing/splitter/wheel fairing setup, and it would be more important for a high power Exovette.  Could do wonders for both Cd and downforce/balance and make the car a lot faster on track.  I wonder how much the lack of aero had to do with the Exovette 40th place finish at the UTCC, 20 seconds behind the full race Challenger?  I haven't' seen a write up of the event, was there something else going on?

Keith Tanner
Keith Tanner MegaDork
5/24/19 11:58 a.m.

The Exovette was very much in unsorted prototype form at the UTCC, so don't take the lap times as representative of what the platform is capable of doing. You're right that Exo..things have always fared poorly at the event, though. Exoskeleton cars are always going to be draggy by their fundamental nature. Cover up that exoskelton and it's no longer an exo. 

There is an aero Exocet in existence - one guy put a Catfish body on one, which is an interesting crossing of the streams. You'll have to watch out that you don't start working your way back up to the weight of a full body Miata as you try to streamline the chassis. At what point is it easier to pull weight out of the Miata instead? I don't know enough about the Corvette weights to comment there.

accordionfolder
accordionfolder Dork
5/24/19 12:51 p.m.
Keith Tanner said:

... At what point is it easier to pull weight out of the Miata instead? ....

Kind of ... because even if you get back to the weight of a miata w/o a cage - AND can have a same or less than drag (very possible if you're picking the body/undertray) + downforce AND you get the stiffness bonus of an exocet (IMO one of it's greatest strengths, right behind weight) than I think you're going to be ahead still. A miata w/ a cage is a bit heavier and that weight is pretty high up relatively speaking. Even then - w/ a full cage you're still going to see more flex since it's tied to the convertible unibody and weight up high I think. Well, that's my theory anywho, but I love how easy it is to work on my Exocet (the trans tunnel is removable in ~2 minutes!!, I can reach in through the side to access the engine! etc) - another often over looked bonus. Especially for track rats like me, are you really competing for anything or do you just want to pretend to be a race car driver for cheap (consumables/etc)?

Hopefully I didn't derail this too far....

Keith Tanner
Keith Tanner MegaDork
5/24/19 1:04 p.m.

I'm not sure an Exocet is any stiffer than a caged Miata. I'm also not convinced there's a significant difference in the vertical CoG - roll cages have to be above the driver.

My V8 Miata track Miata (with full weather gear, including electric windows) is right around 2400 lbs and includes pretty good aero. That's about 600 lbs heavier than the Exocet Sport we just finished with the same drivetrain. Add the cage to the Exocet, and you're around 500 lbs lighter than the weatherproof Miata. So there's your weight budget for making the Exocet slippery.

accordionfolder
accordionfolder Dork
5/24/19 1:28 p.m.

In reply to Keith Tanner :

An exocet is definitely stiffer than the average caged miata from my experience. It's a rare spec/track miata I've seen that the cage is tied to the front struts properly, that has triangulation to the front, that has good floors, etc....The exocet has real analysis done on it's structure.

I'm also unconvinced your v8 track miata is a good comparison, the necessary power goes down with lower weight and aero advantage. (what was that front windowless miata w/ a dyno'd 130ish hp that was fighting with the big boys in socal? I think it was a blackbird fabworx car?) A bodied exocet sport + k20 would be potent I think, but again - I'm just doing bench racing here. In real life I'm very pleased with my unbodied, 1.6 supercharged exocet - it's still way more car than I have talent presently.

Keith Tanner
Keith Tanner MegaDork
5/24/19 1:40 p.m.

I thought we were talking about power vs drag. I'm comparing two cars with the same powerplant but very different drag numbers. By the time you've made the Exocet work as well as the Miata aerodynamically, how much weight have you saved? Thus my track Miata is a great comparison. At higher speeds, weight is less important than drag. So how much extra weight would you add if you tried to make an Exocet as slippery as a Miata? And once you've determined that, is it easier to start with the Miata in the first place? It's a matter of reducing variables down to the basic questions.

The Miata has "real analysis" done to its structure as well. Since neither of us have any actual numbers to compare in that regard, it's not a worthwhile discussion. I do have the facilities to actually test the structure here at our shop, but I don't have an Exocet Race on hand or a good reason to tie up our development area to do it just for a forum thread.

accordionfolder
accordionfolder Dork
5/24/19 2:12 p.m.

**edit WOAH this is a big response - wall of text ahead - sorry, not sorry**

Lol, alright - here we go:


---------------------------------------------------------------------------------------------------------
"I thought we were talking about power vs drag. I'm comparing two cars with the same powerplant but very different drag numbers. "

This was my original thought that you responded to: "Kind of ... because even if you get back to the weight of a miata w/o a cage - AND can have a same or less than drag (very possible if you're picking the body/undertray) + downforce AND you get the stiffness bonus of an exocet (IMO one of it's greatest strengths, right behind weight) than I think you're going to be ahead still."


---------------------------------------------------------------------------------------------------------
"By the time you've made the Exocet work as well as the Miata aerodynamically, how much weight have you saved?"

Again, above, I'm saying I think (big emphasis on theory here, lol) you can get it back to the weight of the miata before exocet'ing (and lighter than your v8 car), but get a stiff frame, cage, and better aero - assuming weights from similar fiberglass bodies (circle track, etc). I **think** you're still getting more bang for your buck (though the time sink is real)- Though we're playing with cars on a race track, so it's all pointless money burning anywho.


---------------------------------------------------------------------------------------------------------
"Thus my track Miata is a great comparison. At higher speeds, weight is less important than drag."

But if that's how track times worked, we'd all be driving landspeed cars, eh? Corner speed and consumables are there, but lets be real here. I was implying it would be a lighter, **more aerodynamic** result than your v8 car if you did it right (hahaha, so much bench racing). But if we want to do apples to oranges, I doubt your v8 car is faster than an equivalently shoed c5/c6/c7 vette w/ the same driver (why aren't we all just driving corvettes!?)


---------------------------------------------------------------------------------------------------------
"The Miata has "real analysis" done to its structure as well. Since neither of us have any actual numbers to compare in that regard, it's not a worthwhile discussion. I do have the facilities to actually test the structure here at our shop, but I don't have an Exocet Race on hand or a good reason to tie up our development area to do it just for a forum thread."

But my point wasn't that you need to, but that you DIDN'T before you built your cage/car - unless I'm misunderstanding your statement? The car is based on a 20 year old unibody. Exomotive did the analysis BEFORE they built/sold, and you are getting a brand new "unibody" that's all - it's a pretty good foundation wheel fitment issues aside (though those are really annoying).


---------------------------------------------------------------------------------------------------------
And good lord who WOULD tie up anything in the real world for a forum thread?! lol - I just have a completely bat-s**t theory, and I think it holds more water than you're implying - that's all. I'm definitely not going to waste my time trying to eak out more performance when I can work on my driver-mod anywho - I've already gone so far left field w/ my exocet that **really** I probably should have stuck with my spec miata longer, but hindsight is 20/20... Exocet's do make the world's silliest autoX car though - I enjoy what I've built.

Keith Tanner
Keith Tanner MegaDork
5/24/19 3:04 p.m.

I'm just trying to look at how far you modify an Exocet before it becomes the wrong platform to start with. That's all. The Exocet has the advantage of lighter weight but as jwagner pointed out, they're freakin' bricks. By the time you've overcome that, is the Exocet still the right platform? That's the question. Not "is the Exocet the best fastest lightest stiffest thing ever", but at what point are you basically down the wrong rabbit hole?

You're assuming that it's possible to end up with a superior result based on...well, based in large part on the fact that you want that to be true wink I'm trying to figure out what it would take to get to the same level as a modified Miata. Like you said about your Spec Miata, if you start by looking at the end result you may find there's a better way to get there. I like Exocets. I've spent a lot of time in them, from stock four cylinders to the supercharged V8 XXXocet. But I'm willing to step back and look at them and try to figure out where they stop making sense. They're fundamentally bad at punching a hole in the air. How much compromise does it take to remove that fundamental problem?

Extrapolate all this to Exovette as you see fit.

FYI, my V8 Miata was comfortably faster than a C6 Corvette with much bigger rubber at the Targa Newfoundland. Wasn't the same driver, the other guy was better with a number of podiums and 10 years of experience at the event.

1 2
Our Preferred Partners
GI4IAM3md1sHXy1l5Npgfo8hk809m1sitwEo0bGOkhS09NR2CDgOQBpU1VzGa0fu