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bonjo2
bonjo2 GRM+ Member
11/23/22 3:02 p.m.

I figured I would do my next build on the Grassroots Forum, vs. Miata or Locost.

GOAL.   High Down Force, F1-Like, Street/track monster...

Modified Exocet Sport Frame.  Big V8.  Turbo.  Paddle Shifters yada, yad, yada..

 

bonjo2
bonjo2 GRM+ Memberand New Reader
11/23/22 3:05 p.m.

 

Colin Wood
Colin Wood Associate Editor
11/23/22 3:32 p.m.

You had us as "big V8" and "turbo."

Excited to see how this turns out for you–which will likely be an absolute riot that makes lots of angry noises.

birdmayne
birdmayne GRM+ Memberand Reader
11/23/22 3:38 p.m.

Uh yes, tell me more

rustomatic
rustomatic HalfDork
11/23/22 4:38 p.m.

That sounds amazing.  Are you a Formula One driver?

Mr_Asa
Mr_Asa UltimaDork
11/23/22 5:16 p.m.

Very nice.  Sounds like a good recipe for wearing the brown pants.

11GTCS
11GTCS Dork
11/23/22 6:22 p.m.

Yes please, you’ll fit right in here. Help me understand the performance potential  of an Exocet with V8 power as well?  I’m guessing the “are you an F1 driver” question is a hint? devil

MyMiatas
MyMiatas Reader
11/23/22 6:58 p.m.

No one has determined what differental that is!??  The V-8 looks like a new crate motor from GM. No dust or water spot on that intake.....

jwagner (Forum Supporter)
jwagner (Forum Supporter) HalfDork
11/24/22 11:53 p.m.

Just hit the Watch Topic button, should be an interesting thread. 

Exocets are pretty light in the tail end and I don't expect the V8 to make it better.  Running a bunch of aero should do a lot of good, at least at higher speeds.

bonjo2
bonjo2 GRM+ Memberand New Reader
12/3/22 11:15 a.m.

Far from an f1 driver.  Mostly a fan.  I had always been low or no tech, so this will be different.  ECU, GCU, TCS, ABS and One Gauge, tablet etc.. = too many computers...

want something for crazy fun rides, track day, drag race, cruises, autocross etc.. no changing tires, all fun, nothing serious

Up, Down and clutch by wire, er TPS sensor

bonjo2
bonjo2 GRM+ Memberand New Reader
12/3/22 11:18 a.m.


valve body modification test complete!

bonjo2
bonjo2 GRM+ Memberand New Reader
12/3/22 11:32 a.m.

In reply to MyMiatas :

LS3 from previous build. TSP cam, trick flow heads etc.. 492 rwhp.   Rear end from 2021 SS camaro, with under 500 miles.  Trans BMW 750 6k miles valve body some sort of M sport model.   Ebay/craigslist etc.

SV reX
SV reX MegaDork
12/3/22 11:35 a.m.

Watching...

singleslammer
singleslammer PowerDork
12/3/22 10:37 p.m.
bonjo2 said:

In reply to MyMiatas :

 Trans BMW 750 6k miles valve body some sort of M sport model. 

This is something that I feel like I need to research.

fouckhest
fouckhest New Reader
12/5/22 9:23 a.m.

Oh wow, this looks like its going to be good! cool

Shifted
Shifted New Reader
12/7/22 8:19 a.m.

This is great!  We're planning on placing an order for an Exocet "Race" in a couple of months, and hunting for a donor Miata.  Any tips on the Exocet ordering process are welcome.

 

I'm looking forward to following the progress on your build.  Looks awesome so far!

 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
12/7/22 5:01 p.m.
singleslammer said:
bonjo2 said:

In reply to MyMiatas :

 Trans BMW 750 6k miles valve body some sort of M sport model. 

This is something that I feel like I need to research.

There is a guy on rx7club with (I think) an LS2 and a twin clutch trans from a BMW.  Probably this unit.  The fun was calibrating the trans controller himself, and 1st gear is typically painfully low on these type of transmissions to minimize how much clutch slip is needed.   But he raves about how awesome it is.

bonjo2
bonjo2 GRM+ Memberand New Reader
12/10/22 2:48 p.m.

It's an HTG Gearbox Control Unit, GCU.  It's supposed to work with the DBW to blip etc.  based on videos online, shifts faster than I can.  So, only two pedals, go kart style.


This week I hope to get engine placement sorted out.  There's a ton more room than my previous car, but figuring out where to place turbo a challenge.

 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
12/10/22 6:25 p.m.
Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
12/10/22 8:04 p.m.
Shifted said:

This is great!  We're planning on placing an order for an Exocet "Race" in a couple of months, and hunting for a donor Miata.  Any tips on the Exocet ordering process are welcome.

 

I'm looking forward to following the progress on your build.  Looks awesome so far!

 

Ordering process is fairly straightforward but production takes time, so don't order the week before you want to build :)

The powdercoating offered by Exomotive is very good quality, but has two problems: increased shipping cost, and you cannot modify the frame without grinding off your pretty powdercoat. The frame doesn't have brake line brackets and grounding points and the like on it, so I like to built it bare and weld on what I need, then tear it down and get it coated (or painted) locally. It doesn't take as much extra time as you'd think, and you end up with a better end result.

Aluminum floor is lighter but not as strong. Your call there.

Cycle fenders have always sucked.

te72
te72 HalfDork
12/10/22 10:54 p.m.
Shifted said:

This is great!  We're planning on placing an order for an Exocet "Race" in a couple of months, and hunting for a donor Miata.  Any tips on the Exocet ordering process are welcome.

 

I'm looking forward to following the progress on your build.  Looks awesome so far!

 

Keith hit the high notes, but I have my own criticisms. The instructions on Exomotive's site are likely from an early build, as things seem to have changed in production as time went on. At best, they're to be considered generic guidelines. For example, the bulkhead plates, at least in the Race chassis are quite tricky to rivet into place. Why these weren't just welded in steel of a similar gauge like the floors, I will never understand. Would save time, headaches, and tool purchases to do the drilling in such tight quarters...

 

The "complete brake line" package they sell is a joke. Half of the lines are complete, the other half are DIY. I've built hundreds of hoses at work over the years, never had a single one come back or give me this much trouble. You wanna know our secret? We use crimp on fittings. The old style ferrule and twist on style fittings are simply outdated, and a significant waste of time and money. If you're lucky, you get it right on the first try. If you're like me, you get it on, try to bleed the brakes, only to find out that you made a mistake. So you get to take the line off, take it apart, clean it, rebuild it, and try again. If you're lucky, you get it right on the second try. If you're like me... well, you get the point. If you're able to fabricate hard lines, this is less of an issue. I've never been good at bending hydraulic lines, unfortunately. Likely a matter of having proper tools, but it's just a job that you do once, why spend good money on tools you won't use again? If you can pressure test your lines before putting them on the car and filling them with fluid, that would also mitigate the issue, somewhat.

 

Better option than Exomotive's brake line kit? Have someone like Pegasus Racing build them for you.

 

Order the deeper wiring tray from Speedcircuit. Otherwise it's just wasted space between the wiring tray and transmission tunnel.

 

Speaking of the transmission tunnel, the hole that's in there when you get it isn't likely big enough. I had to trim quite a bit out, and I still can't shift into 5th or 6th. Reverse is also quite difficult. Maybe that's something unique with my setup, but it's not really an issue on track.

 

Seat fitment... ugh. How Exomotive got this so wrong is beyond me. Two issues come immediately to mind. One, the cross rails are spaced for stock Miata seat rails. Have you ever seen one of these with stock seats? Likely not, because stock Miata seats are less than ideal for a Miata. You NEED a proper seat of some sort for an Exocet, full stop. Problem here is that the sliders they sell, as well as seemingly most seat brackets, won't cover the distance between those rails. So you have to make adapters. Just one more step that really should be done during production. Better yet, add a third cross rail so your seat can bolt up properly.

 

Seat mounting issue number two is a bit more bizarre. If you are able to get your seat to mount to the included tubes, your ribs are basically right on the outer "door" bar. Perhaps not a huge issue on an autocross car, but where there's traffic, I want a bit of space between the squishy bits and the bars... so my seats are mounted up and as close to the transmission tunnel as possible. This has the unfortunate side effect of making it difficult to adjust harnesses.

 

Speaking of harnesses, would be better if the sub belt mounting point was on the rear bar as opposed to the front. Being so close to where it mounts to has the side effect of leaving the sub belt's buckle sit between your thighs, not particularly comfortable.

 

Allllll that said? Once you get the thing sorted out in the slightest, you'll be having too much fun to really care about the hurdles you overcame to get there. On that note, to the OP, I suggest wearing brown pants. Even in BP form, at least in autocross situations, these things are a riot. You're crossing a full threshold of silliness here, and I fully support you in that pursuit. =)

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
12/10/22 11:29 p.m.

I always prefer to build hard lines than do a complete brake system in flex lines. You can bend them by hand if you want, or get an inexpensive bender from HF for a couple of bucks - I've only used mine a couple of times. You do want a good flaring tool but a good flaring tool will always come in handy. You can also buy pre-terminated lengths of nice straight hard line from auto parts stores, which makes it just a matter of lego.

If you don't want to fabricate hard lines, figure your lengths and order complete lines from Fragola. They'll be fully crimped and ready to screw fittings on to, because life is too short to screw around with putting fittings on braided stainless -3 lines :)

jwagner (Forum Supporter)
jwagner (Forum Supporter) HalfDork
12/11/22 2:38 a.m.
Keith Tanner said:

I always prefer to build hard lines than do a complete brake system in flex lines.

I agree.  Buy some NiCopp brake line and the tools and learn to do by doing.  We were first timers on brake hard lines and didn't hit anything that wasn't doable.

te72
te72 HalfDork
12/12/22 10:15 a.m.

Brake lines a matter of preference, perhaps? I've never done them on the same car twice... In the case of our Exocet, have two seasons on the car, no complaints about the brake lines (which are end to end flex lines) or the braking system as a whole.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
12/12/22 12:28 p.m.

In theory, there's still a bit of flex in flex lines so you can get a slightly softer pedal with it. Also, that flex will lead to more difficulty in threshold braking as you've added a spring rate to your pedal/caliper interface. In practice, however, I'm not sure it's enough to matter. But hard lines are my choice as they're basically indestructible unless you let them rust or you don't anchor them properly. They're also able to bend at a smaller radius so you get a cleaner install. I would say they're more work for a better result, but I'm not sure they're actually any more work by the time you've wrangled the flex lines into position.

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