The LHD JDM conversion project

[Hugabuga]

Hi Primemembers and Friends

I have started a new project, starting from a bare JAPANESE JDM chassis I bought in Germany this summer.
Car was involved in a very light accident and, because it was a RHD (Japanese car) it has begun to be savagely stripped, rather than being repaired, just for its good body parts to repair another one: the black LHD german one in the back of the picture.

Good thing is the JDM car was already registered in germany with german documents before its accident, so all the import duty taxes were paid with all the administrative issues solved to become a european vehicule with a small unconventional “NA1+7digit” Vin number instead of the usual 17-digit on

So, considering all the benefits from its documents, I couldn't resist and went to germany to buy the car, or what was left from it!

Here are the pictures I had to take my decision before I got there.

Chassis seemed straight and in its OEM condition/paint so that was just perfect to start a project!

Once I arrived in Germany, I managed to include in the deal all the parts he had not sold yet but removed from the car, like fenders, rear bumper, suspension arms, ECU's... I arrived too late to save the engine and the JDM 180km/h speedo unfortunately

Owner packed all the parts back into the car the best he could, with tape and plastic covers to last the 2000km journey to Portugal, and here is how I received the car loaded on a truck

At this point, car was already too far stripped and incomplete, for me to wish to rebuilt it as a RHD car!
That would make no sense for me, having all this trouble of rebuilding it, to remain a RHD car at the end with all of its inconveniences for a daily use in a LHD continent.

This car had begun to be cannibalized just because it was a RHD! So, I had to change its destiny, this car could not longer be a RHD

My main project is then to convert this JDM car into a LHD car, keeping all the JDM details I can of course :wink:

 

[shawn110975]

we are brothers from another life LOL

you need anything Hugo let me know I got you covered

I have everything you need like USD wire harness's etc.

 

[Hugabuga]

First step was to make sure chassis was not bent or deformed, even if the accident was very light I had to make sure it would worth my effort fixing it
Car was completely stripped and placed on a car bench.
Removing frame panels wikens the chassis, I wanted to make sure it would stay on its oem specs dimensions all the time so car will be kept bolt to the car bench during all the process of the conversion.
Being completely stripped also removed all weight and effort on the chassis, I can't imagine doing such a modification on a running car fully loaded just laying on its tyres

As I will be doing a full color change to Championship White, it was better to fully strip it before the conversion

My major concern was not to loose any of the chassis stiffness with the LHD conversion

There are 2 major LHD/RHD specific panels in the NSX:
-the footwell/firewall panel
and
--the dashboard upper panel, that goes all the way on top of the front shock tower frame.

Dashboard panel links both A pilars and the shock towers together
Firewall panell links the floor, the tunnel, the rails and dashboard panel togheter, that is simply the most crucial part of the nsx chassis!

 

[Spooler]

Quit screwing around and stuff some kind of V-8 in this one :biggrin:

 

[Hugabuga]

Spooler, perhaps I could fit 2 electric motors at the the front :wink:
Shawn110975: we are brothers in cars

Before I started to perform some surgery on the jdm, I had to find the firewall panel. These parts are too costly to get them new at the dealership, so I got mine from a breaker that sold me an nsx cockpit clip.

There is a lot of welding spot points to drill to remove the firewall panel, but at the end it finally came out in one piece the way I needed it

Just by looking at the panel, the brake booster will be the problem of the conversion...

- - - Updated - - -

If you carrefully look at the folowing pictures, the firewall panel links no less than 15 other panels togheter

That is the point when I had serious doubts about doing the conversion or not

 

[shawn110975]

don't give up if you do this your now a confirmed master of the NSX

 

[Hugabuga]

After carefuly looking at both RHD and LHD firewall panel I noticed they are very similar from the floor to that white bar (expect for the hole of the heater water evaporation tube... and some squary nuts pieces that can easily be removed)

So my crasy idea, is to cut the RHD firewall panel by its middle ( the white bar) and weld the complete LHD panel on top of it!
Panels will be paretially superposed, I will leave all weldings INTACT of the RHD panel from that white line to the floor

Advantages: I won't be messing with the tunnel, the floor, the side rails, that means 10 panels frame at least
I will leave 4 lines of welding spots of the RHD JDM panel untouched, that is about 60-70points not to worry about!

Good think is the NSX is hand built, means that welding points are done by hand, not a single car will have its welding spot located at the same place!
So,as the LHD firewall had to be drilled by its welding points to be removed, the drilled holes will not even match the welding points of the RHD panel underneath, that is just perfect to be used as a metal sheet support rather than welding 2 holes togheter! )

And, by welding a 2nd panel on top of the original one I should be reinforcing the structure rather than weekening it right??
At the end, if one removes the carpets, he shouldn't be able to notice the modification as he will only see a complete LHD panel :wink:

 

[A.S. Motorsport]

This is a very neat project.
Best of luck, if there is anything I can do to help let me know.

 

[Hugabuga]

Thank you AS Motorsport

The brake booster is located much lower and further away from the wiper cover trim in the RHD car. It is located so much further, that the wiper plastic cover trim is straight in the RHD but not in the LHD!
The brake booster and the master brake cilinder are the same, only difference there is due to the firewall panels themselves, the RHD has a bumpy fixing area for the booster of about 4cm high, while is is plan in the LHD! Don't ask me why I have absolutely no idea why they designed them that way

Here is a comparision pictures of RHD and LHD front bays

So, the first solution I found was to simply replace the brake booster with a more modern and compact one, so i could keep the original RHD cover, and the dashboard panel of course.

Brake booster is a low technology part, it exists since 1920, only job is to use vacuum "power" to help pushing a piston! And at the end if I would loose any brake efficiency because of the booster, I could always fit some nice 6-piston brake caliper setup to compensate it :biggrin:

So my route was to simply replace the brake booster for a much narrow and long one, so brake fluid reservoir culd be placed further away and that way I could keep the RHD upper panels.

This thing is huge but very thin, it is made of a single diafragm.
Searching on internet, I found some compact dual-diafragm boosters, much smaller in diameter but thicker because of the dual mechanism inside.
That was exactly what I was looking for, all I needed was to make sure the fixation pattern would be the same

But then I tought car won't never be a pure RHD or a LHD anymore..it would become some sort of handicraft modified car
And I would probably jut be shifting the design and room problem to another part of the car that I will only found out during the reassembling of the car, after all if Honda engineers desgined the LHD panel that way there must be a reason and they had all the time to test their solution.
I have only one shot after car is painted and ready for the reassembling

Plus, I would always be driving with the worries of an aftermarket brake component in my mind!

So I gave up the idea of using a different brake booster , car will be converted to LHD with genuine OEM LHD parts only :biggrin:

 

[A.S. Motorsport]

Yes that whole upper bulkhead is very different RHD vs LHD i know that for the strut bars it they had to be totally resigned to clear the wiper mechanism.
I know Honda did it similar on Legend and Vigor which where designed at the same time, (those cars had mirrored chassis even the glass on the Legend was specific)

Will you be converting the ABS system and wipers to LHD?

 

[Hugabuga]

My first idea was to keep the ABS and the RHD wiper yes, or perhaps a single wiper blade for a sportier look...but I gave up that route and decided to perform a FULL LHD conversion rather than some hibrid one. Car will become a LHD car in every single part

So, it was time to start the mod!
I cut the RHD firewall panel by that white line right above the 4th line of welding spots...and remove the top of the firewall

OH NO!!! WHAT HAVE I DONE!!!

A Good way to see it is that now I can only move forward in the conversion:wink:

 

[JRZ]

Looking good HUGO. At this rate, you'll be one of the top 10 NSX guru's in no time. Keeping this one for yourself?

 

[whrdnsx]

Hello Hugo
It's a challenging Job.
Here's the instructions for you, but in reverse.

http://www.nsxprime.com/forum/showt...-Conversion-Pics?highlight=diy+RHD+conversion

Good Luck!
let me know if you have any questions.

 

[Hugabuga]

Thank you Wayne. I read your post many years ago and I always planned to do the same mod one day. If we knew and could go back in time we would simply trade our cars instead of converting them!
But in your case you started from a complete running car, I would probably take the same route if my car was not as much incomplete as it was.
You related so many problems and differences that I decided to get rid of ALL of its RHD specific parts from the start.
My modification will be focussed on the chassis frame only
Finding LHD parts seems a much easier problem to me than trying to use and adapt several RHD parts like the ABS, wipers, heater, radiator tubes, harness and so on

I can't say at this point wich way is easier, all I know is I probably won't have the courage to do it on a perfectly running car.

JRZ I will probably need to sale one of my other nsx's to finish this one, but then I will probably keep it for a while, until I start a new build I have 3 other nsx's right now:tongue:


Now that the firewall was out, it was time to look at the upper bulkhead frame.

Honda part list suggests it is a unique huge part (#31),

I can't replace this complete part without unwelding all the car, this frame links the shock towers to the A pilars, I am not going to mess with that...or am I??

Carefully analysing the upper bulhead panel, by this dissected bulkhead pictures, I noticed it is actually made of 2 panels weld togheter!!

Panel #1 covers the shock towers and goes all the way to hold the windscreen, and is conected to the A-pliars of course.
It has all the RHD/LHD specific fixing points for all the front bay component as the wiper mechanism, the fuse boxes, the harness, the clutch oil reservoir and so on...

Panel #2 goes right under panel #1 , and is also connected to A-pilars
it has all the RHD/LHD specific fixing points for the interior cockpit components located under the dashboard, the heater unit and its matching air vents, some Ecu bracket and even the pedal assembly and the steering column fixing area.


Firewall panel goes right under the joining point of panel #1 and #2 (red circle in the picture)

Because of that anoying RHD/LHD specific bump shape of the firewall, I need to change the chape of that joining line of panel #1 and panel#2
I have only 2 ways to change its chape: by deforming it or by replacing it by the matching LHD section :wink:

My idea was then to cut panel#1 somewhere between the joining are to panel#2 and the bottom of the windscreen fixing location.
Then I would replace that front frame, as marked with tape on the poor JDM car, keeping all its upper section under the windscreen and the dashboard defroster untouched.

cut by the tape line, bulkhead and shock tower connection to the A pilars would remain untouched, and I will only be messing with the connection of one shock tower to another...right?

 

[A.S. Motorsport]

Do already have all of the sheet metal from the LHD frame? also are you using the factory welding diagrams?

 

[Hugabuga]

AS Motorsport: I have a LHD cockpit frame to play with, I do not have the factory welding diagrams but we can notice the welding spots very easily in the nsx so I guess I managed without them. To be honest I didn't know these diagrams were available

The link of the 2 shock towers was worrying me if I cut the upper panel.
Many performance parts manufacturer, like AS Motorsport himself, have some amazing reinforcement strut bars to reinforce that exact link, I would be doing the opposite by cutting it the upper panel!

The use such a strut reinforcement bar could dissipate my worries, but the welding of the 2 upper panels, being so thin and made of aluminium would still remain a poor link, and would still have the tendency to crack one day.

So, I used the same idea of superpositioning panels, exactly as I would be doing with the lower firewall panel!

I cut the red LHD upper panel from the mortal remains of that red LHD cockpit clip, to also include the shock towers!
It would then be welded it in top of the black RHD upper panel that will remains on top of the tower after the cutting.

Last chance before cutting the JDM upper panel is to place the LHD one next to it to make sure I want to do this!! :biggrin:

So, shock towers will remain linked to the A-pilars by their original welding spots to the upper panel
Both towers would become linked togheter by the 2nd red upper panel welded on top of what is left from the black RHD one, on top of the towers

 

[A.S. Motorsport]

Coming along nicely!
Yes, I have the welding diagrams and frame/structural replacement documentation from Honda here.

 

[Jhillen86]

super awesome project! good luck with this car!

 

[Honcho]

Amazing project! I haven't seen anything this ambitious since Anil did his NSX-RR.

 

[Spooler]

Here these are again as requested from Huga as we both share the same fantasy, original photo also .

With the driver we can see almost exactly how it would look !

Two smaller tunnels each side of chair replaces center ala MC... then all you gotta do is...:biggrin::biggrin:

Happy welding Huga.

re S









- - - Updated - - -

 

[Hugabuga]

Thank you Spooler, that would be the ultimate race car in my opinion, much safer and probaly more fun to drive. Technically it won't be too dificult to build, just cut that tunnel and have the water hoses passing inside the car, so that would be a perfect car to race during the winter time or driver would fry inside the cockpit because of the heat
Not so much fun for a daily driver, because there won't be any room left for a blonde... the MacLaren F1 has a single driver seat, but at least you can have 2 blondes in the backseats :biggrin:
Nice photoshop skills by the way

Because of the bumpy shape of that brake booster, the new LHD front upper panel won't fit on top of the lower RHD dashboard panel (panel #2 in the ealier picture), and neither the LHD firewall panel under it!
My first idea was to keep the lower RHD panel and adapt it, but it has so many LHD components fixing points under the dashboard that I decided to replace it as well.
All these 3 parts will be reassembled togheter like a 3-pieces puzzle

So again I did some more cutting to the red cockpit frame

There is has almost nothing to hold this THING togheter, all my rigidiy and stiffness worries are making sense now!
The use of a car bench to hold the JDM was reassuring me somehow, even if a bare chassis won't bend just by removing its front bulhead and firewall

So finally here are the 3 panels that I will be replacing in the JDM: le lower bulkhead panel, the firewall and the upper front panel

I made a mistake by unwelding the steering column bracket/support from the lower dashboard panel. My first intention was to keep the RHD lower panel, but because of the booster bump shape it is better to replace these 3 parts all togheter


So, it was time to cut the JDM and start to fit the new 3-pieces puzzle
First part to fit is the lower bulhead panel, it won't fit with the firewall in place, and it has to be weld on top of it before it gets covered by the upper panel.

The dashboard reinforcement bar goes on top of the lower bulkhead panel, so as for the rigidty of the chassis the bar takes the role over the lower panel :wink:
I left the fixing points of the dashboard bar to the A-Pilars untouched and made the cut after that area on purpose.

 

[Hugabuga]

Some fresh updating pictures.

The JDM car with the 3 RHD panels removed and the new LHD upper inner bulkhead section in place:

Officially at this stage is not a RHD car anymore....but neither a LHD yet....:biggrin:


Then the fiting and welding of the LHD firewall

Here some marks of the overlaying of the 2 firewall panel over the tunnel:
the LHD overlaying the lower section of the RHD

And the welding of the upper panel to the top of the firewall.

This one is my favorite: the poor guy taking a short break after a neverending welding job...

 

[Hugabuga]

More updating pictures :biggrin:

Finally the last frame panel to complete the conversion: the front upper frame, linking the 2 shock towers

After grinding the surface to smooth the welding points...

At this point, it was time to remove the car out of the car bench:biggrin:

And here it is, ready to be water jet cleaned to remove all the aluminium powder left on it from the conversion work!

The wonders of filling material and paint preparation have now started, any conversion mark and grinding scars must dispaear

Car is to become a Championship NSXR
Stay tuned :=)

 

[shawn110975]

your a beast if you need anything let me know I have everything even complete wire harness's brackets, bolts you name it I got it

but only for you Hugo

 

[Hugabuga]

Thank you Shawn, I will probably need some items but I am too far from the reassembling yet to make a list of what I need. I will keep you in touch

A final jetwash before the long paint preparation...
Afterall it's not everyday that we can wash inside an NSX with water
Even the undercarriage of the cassis was degreased

Here the new steering rack and heater evaporation holes on the lower untouched section of the car.
The old RHD holes will simply be closed with gommets...enough of weldings for this poor car!

As the engine bay is already black and car is to become an NSX-R replica,this part will be kept original and not be painted.
Idea is to preserve all the Japanese stickers intact for that final "JDM" genuine touch