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11 Posts
Discussion Starter · #1 ·
I am building a J35A4 Exocet Racecar.
Originally hosted on which appears to be dead.
I might need about 10 text blocks to get up to date on this.

So it all started when I bought a junkyard J35A4 from a 2002 Honda Odyssey. It was cheap. I had originally wanted to build a K series, but the J was cheaper. I've been racing an F22c (S2000) for years, and had a few other Honda racecars, so wanted to stick honda powered.


I picked up a frame that someone had almost started, then left to rust in his backyard. It was a little cheaper than buying a new frame, and skipped the 4-6 month wait.

I rolled it against the wall and started removing the rust.

There were some pretty bad spots.

Really bad:

But I made progress:

Finally got some primer down

I decided to do sections at a time.

2 Coats of primer on the floor:

Eventually I was able to put rhino liner on the floors:

Meanwhile i started pulling apart what was left of the donor miata:

I only needed the Transmission, control arms, and rear subframe. This car must have seen some offroading?

Pressed the bushings out of all the control arms:

Cleanup the rust/dirt:


And gloss black paint:

I did every arm and knuckle/spindle:

Put the frame on wheels and upright:

11 Posts
Discussion Starter · #2 ·
Where i left off:

Finally got the chassis fully primed:

Trying to pick a shade of blue:

Picked my colors:


And silver for contrast:

Painting time

And the rear trans tunnel:

Removed to re-bush the differential

Had to burn some of the rubber off the mounts to go 100% polyurethane


Drilled control arms for zerk fittings too

Painted the diff, bought new axles, and reassembled the rear end

Sortof on wheels

Painting brakes

1st coat of blue (metallic cobalt)

Touchups between coats

And done... sortof:

Not bad...

Next... Got rid of the miata engine, and time to get to work on the V6.

11 Posts
Discussion Starter · #3 · (Edited)
Propped up the frame to drill and install rivnuts in the lower floor to route brake lines, fuel lines, and wiring.

Rivnuts installed:

Cleaned out the trans and cut a notch in it for the Honda starter:

Staged the front suspension inside, and minitec subframe/adapter.

Now for the Engine. Drained the old oil.

Removed the old oil pan, windage tray, and oil pickup.

New oil pan:

Did a valve job too

And while they were off, painted the valve covers:

Actually, the whole upper manifold too...


Then the springs too...

Had to keep the blue/silver theme even onto the coilovers:

Lowering the engine into place (actually did this 3 times to get the oil pan to seal, among other things)

And mated it to the transmission adapter, and put a few front control arms on there too.

Some friends came over and we dropped the frame on top.

Had to remove the upper intake manifold and lower runners to replace fuel injectors.

And also redrill the fuel rail to reverse-mount the upper manifold.

All reinstalled, the manifold now points forward:

A few cuts and holes drilled into the starter to fix some riding conditions.

And starter installed (once i ordered an extra long bolt):

Drilled up the frame for kick panels:

Painted and drilled up sheet aluminum kick panels. Gloss on the outside, Rhino on the passenger side.

Installed driver side kick panel and painted steering shaft.

Painted the brake booster and pedal brackets.

Installed brand new clutch and brake cylinders.
Had to fabricate all new stainless braided lines for everything.

Running the brake lines:

Steering and pedals in:

Trimming suspension to make it fit

This is why i painted the chassis instead of powdercoat. I dinged it up, but it's an easy respray.

Installed a prop valve to adjust rear brake bias on the center tunnel.

Made a quick throttle bracket to space the cable appropriately and improve clearance.

Test fit and drill up the forward transmission cover:

Painted the cover blue and installed a basic frame for a shifter boot.

Installed shifter boot and gave the floors a final coat of rhino liner.

11 Posts
Discussion Starter · #4 · (Edited)
Up next.... wiring. Started labeling connectors on a salvage minivan harness i bought.

Down the electrical rabbit hole...
Starting to cut open the donor harness. Most of this is probably going to go in the trash.

I'm missing a plug...

Cutting out wires and connectors i don't need.

Getting messy

Disassembled and stripped the donor harness.
Had to move all the plugs that were on the upper manifold, since it's flipped now.

Making harnesses for the rear end

Routing wiring and fuel/brake lines under floor:

Routing wires through firewall.

Painted aluminum box to house ECU, Relays, etc.

Beginning to fill it up

3D printed a switch panel to test fit/placement

Wired a killswitch, switch panel, and relays.

More wiring, loading basemap to ECU.

Headlights work:

Made a temporary intake.

Close enough to see if it runs

and it did:

11 Posts
Discussion Starter · #5 · (Edited)
Test fitting a radiator. Will have to fabricate some mounts out of 6061 to get it right.

Test routing some Radiator Hose.

The overflow broke off.

Added more wiring. Fan switch and CANBUS from ECU to dash.

Got a piece of aluminum laser cut to match the 3d printed switch panel. Painted it blue to match.

Installed it on the car:

And installed the switches into it.

After multiple attempts to make a seat mount. I bought one for a miata, trimmed it, and installed it.

Got another piece of 6061 plate cut out to make a mount for my digital dash.

Mounted the dash:

Mounted the seat finally.

Bolted a Lithium Iron battery to the rear passenger floor and installed cables.

Cut a piece of aluminum channel and drilled some lightening holes, then painted it.

Installed to brace Lexan windshield.

Installed a temporary half windshield made from Lexan.

Wing mirrors and a few other things go on:

Cut a piece of aluminum sheet to be the electrical box cover. Added compression and a blade seal.

Added sleeving to most of the wiring.

Painted electrical cover. Final route of Radiator hose. Made a proper intake.

Turned on the dash and loaded some gauges to start.

11 Posts
Discussion Starter · #6 · (Edited)
Getting organized:

Updated the dash to add redline, laptimer etc.

Masked off fiberglass clamshell and cut holes for some trailer taillights I found online.

Wired up tail lights to a Deutsch plug.

Got a piece of aluminum plate to bolt to rear end. Temp installed wing stands.

Locate the fuel cell position.

Base frame riveted on.

Temporary Fit-up of Fuel cell.

Painted and installed Fuel cell baseplate.

Final install fuel cell with new C-Channel and wired it up.

Rear fiberglass clamshell mounted.

Added tension cables to wing stands, and painted them.
This will reduce the fatigue on the frame mount bolts.

Wing installed. I swap out all the hardware for better stuff later.

Fire Extinguisher mounted.

Installed plexiglass side panels.

Numbers on the rear. Class may change to TT2/ST2 depending on weight/power results.

New Steering wheel. (Technically old wheel from old car)

Got some fuel jugs to match the colors.

And matching helmet too.

As it sits in the garage.

11 Posts
Discussion Starter · #7 · (Edited)
Had some tubes bent into shape for fender mounts. They mount to the hub and piggyback on the caliper bracket.

Painted the fender mounts.

Custom ordered some aluminum trailer fenders, painted to match.

Mounted on the car.

Got a full size piece of AR-Lexan to protect my face.

Test fit the exomotive hood. Doesn’t fit at all.

Cut the nose off to use as a radiator shroud at least.

Cut some grille material.

And nose all mounted.

Trimmed hood to fit but haven’t mounted it yet.

Attached some roll bar foam for safety:

And mounted a catch can to the firewall to collect oil.

Finally off to the track to test:

So far so good, but it needs some things. The clutch isn’t strong enough, the rear ratio is too short (for this track). Top speed is only 125 and it hits it early on the straight.

Upgraded trailer. No more Uhauls.

11 Posts
Discussion Starter · #8 · (Edited)
I also had issues determining fuel level with the cell, so I pulled off the rear cover to install a Fuel Level sensor.

New wiring for the fuel level and some additional switched power for gopro charging and other things:

And some lighter mirrors, with better adjustability.

Went to a shorter track where the gearing wasn’t as much of an issue. Clutch still makes it hard to put down power early in corners though.

Got a box from Japan:

It’s a new Ring gear and pinion. Putting in a 3.63 final drive will give me the taller gearing I need.

New stronger pressure plate and custom clutch disk from ACT.

I had a vacuum leak to fix. I’d used gasket to plug the EGR ports and it failed.

This should plug that oval port.

Removed the Exhaust, differential, axles, driveshaft, etc:

Disassembled my old differential because I need the cover. I just replaced those bushings anyway.

Touched up the paint on my exhaust Y-pipe while it was off the car.

To get to the transmission, I just have to remove the windshield, switches, and tunnel cover. Not too bad.

New OS Giken differential with my 3.63 gear.

Sealing up the Diff:


Transmission out of the way:

And new clutch installed:

11 Posts
Discussion Starter · #9 · (Edited)
Reinstall transmission.

Install new diff, and reinstall axles, control arms.

Install heat shield on starter to help hot start issues.

Made some bigger carbon endplates:

And new wheels (15x9 -13):

Briefly tried to use the stock Honda engine cover, but didn’t like it:

Dyno day again (dynojet for NASA classing):

Trimmed the hood, and mounted with 2 aerocatches and 2 quick latches:

Took many hours, but got it all adjusted and mounted:

Lack of power steering and slicks makes for a decent arm workout. Decided to try adding a steering wheel spacer to make it a bit easier.

Trimmed a piece of acrylic into a roof panel to see what it would do for aero:

1st lap of the track, it shattered. Oops.

But the new changes felt good. A lot faster than last time. Came 2nd/5 in TT3 by about 0.2 seconds. I had trouble with traffic early on.

Going to put on a rear swaybar and some other tweaks before the next track weekend.

11 Posts
Discussion Starter · #10 · (Edited)
Miata rear sway didn’t fit because of the exhaust hangers, so I made a bracket and floated it off the rear subframe with some couplings.

Made some turnbuckle endlinks using some heim joints / rod ends.

I wanted to make a splitter to smooth out airflow under the car. The oil ban is basically a block in the airflow at this point. Installed some threaded rod into rivnuts into the frame.

Piggybacked a hanging rod off the front sway mount using a coupling nut.

Cut a piece of dibond to shape. Used some clevis on the front rods to make my forward attach points. I riveted some pieces of T-extrusion 6061 aluminum to the splitter.

This is the basic idea to keep air from getting caught on all the engine.

To make an airdam, I cut some aluminum angle into many little clips:

Riveted the clips to the splitter in the shape I wanted.

Riveted some black ABS Sheet to those clips:

And done:

And installed:

4 Posts
Ok thanks! It seems like the J series pretty easily gets the same WHP as the rated crank power when in non minivan setting. So a 240hp J35A4 seems to be almost 240whp without the cats and a good intake

7,611 Posts
Ok thanks! It seems like the J series pretty easily gets the same WHP as the rated crank power when in non minivan setting. So a 240hp J35A4 seems to be almost 240whp without the cats and a good intake
What the engine can transfer to the wheels always depends on the drivetrain efficiency. These are for FWD's around 0.85-0.89 and for RWD around 0.80-0.86. So flywheel power multiplied with that efficiency factor gives you the wheel power. Most swapped engines produce more power because of CAI, H and the other bolts on stuff. That is most likely the cause why whp is equivalent to rated flywheel power.

7,611 Posts
I have wanted to J swap my '03 CRV for a while now. Reading through this thread makes me want to do it even more.
Would be amazing :p. Does the CRV offer enough clearance for the V-design and the exhaust nearby the firewall and radiator?
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