I was going to just unveil this at completion but being as I started this in 2012 I figure I could do with some motivation!
The car was acquired for £800 as a rolling chassis listed in a local car forum. It had no engine, no bonnet, no seats, surface rust, no spoiler and a badly fitting bumper. The previous owner needed to rebuild the engine but lost interest. It was yet another Rx-7 ready for breaking and scrapping.
How it all began... bonnet not included
About me
I'm a mature student, on a very slim budget. I've been modifying Mx-3s for years, going through many iterations:
KLZE 2.5 swap into 1.8 v6
KLZE supercharged with clutched M62 Eaton
KLZE on T595 throttle bodies
KLDE with t3t4 turbo at 291bhp
B5ZE on evo 8 16g turbo
I've loved Rx-7s since I first saw them, and found them incredibly exotic in appearance.
Why v6
Engine budget - I can't throw 3k into buying a rotary, having it rebuilt and buying all the ancillaries. I love the rotary engine but it's just not for me right now.
Fuel economy - from reading forums and talking to owners it seems sub 20mpg is realistic. It's a quick performance car but that's thirsty. I aim for 30+mpg mixed driving at the same power levels.
The challenge - this is as important as the first point. I've always liked doing my own thing. I prefer to see things that aren't normally done. Bolt on modifying is fun and easy, but it doesn't provide the challenge or push your creative requisites.
Why KL Mazda
Lightweight, compact V6.
Made by Mazda. I like to approach this with a mindset of a V6 option by Mazda.
Bonnet (hood ) clearance.
Available in 200hp naturally aspirated form.
Proven performance 291bhp with an eBay £140 turbo and £120 scrapyard engine with 0.5 bar from my Mx-3 days
I have a lot of parts and spare blocks already and the knowledge of the engine.
Easy to work on.
Reliable. My first K series engine ran for 150,000 miles.
Glorious soundtrack.
Project Rules
The shell must be entirely reversible to rotary if required.
Maintain front mid-engine, rear-wheel-drive layout as far as possible.
Keep weight to equivalent or less than the factory rotary twin turbo.
No butchering the firewall.
No movement of key components including the steering rack.
---------- Post added at 08:59 PM ---------- Previous post was at 08:56 PM ----------
Mock ups
SketchUp
Before I even bought the shell I wanted to make sure the KL was going to fit comfortably. One of the core principles of the project was to maintain the Rx-7s integrity: no cutting firewalls, no moving steering racks. The compact nature of the KL excelled here. It required no modifications to the engine bay nor scoops in the bonnet. To check this I visited the shell, measured up then mocked up the key dimensions in SketchUp, cheap and nasty
Lets get real
I needed to see how things were going to be laid out. I had an old 1.8 K8 which shares the same external dimensions as the KL. I took the crank out and was able to just lift the block in by hand, which made things easy to manage. The result was pleasing. Things were fitting in nicely.
K8 Rx7 v6
One long ass gearbox. The K series block looks tiny!
Adapter plate MDF
The next key step was deciding how to combine my power source to the gearbox. I debated using the KL flywheel VS the Rx7 flywheel and clutch assembly. In the end I decided to keep it simple. Rx7 from the flywheel onwards. I began measuring and drawing up CAD files. After a bit of a learning curve I was ready to make my own MDF prototype.
I printed out my drawings, glued them to MDF and got cutting and drilling. Things seem to be lining up nicely.
K8 Rx7 v6
Still front-mid engine layout, much rejoice. Lots of room for turbo parts and cooling!
I then began mocking up a very crude flywheel to crank adapter.
Thicknesses were modified to maintain all original gearbox clutch and starter function. Maintaining the core principle of no butchering.
The bell housing was scanned to assist accuracy in hole placement.
Sketch up mock was made of clutch interface. I didn't wan't to have to pay twice for manufacture.
Before long I had finished the CAD. The flywheel adapter was to be manufactured in a steel comparable to the forged factory crankshaft. This could not be a point of failure!
The adapter plate was intensely irritating to finalise. Holes clashed, but ultimately it would work out.
---------- Post added at 09:00 PM ---------- Previous post was at 08:59 PM ----------
Adapter plate trial with bell housing:
rx7 kl v6 adapter plate
That was a relief...
And the flywheel spacer fit too! Nice lightweight exedy flywheel for FD3S. Whole clutch/fly assembly weighs in same as standard KL and less than RX-7 assembly.
Changing the v6 from transverse to longitudinal logically implied moving the oil pick up to the new deepest point.
Custom sump to match and fit in the rx7 subframe:
I wanted my intake manifold to flow from the front back. Unfortunately the coolant neck was in the way... so chop and weld time:
The car was acquired for £800 as a rolling chassis listed in a local car forum. It had no engine, no bonnet, no seats, surface rust, no spoiler and a badly fitting bumper. The previous owner needed to rebuild the engine but lost interest. It was yet another Rx-7 ready for breaking and scrapping.
How it all began... bonnet not included
About me
I'm a mature student, on a very slim budget. I've been modifying Mx-3s for years, going through many iterations:
KLZE 2.5 swap into 1.8 v6
KLZE supercharged with clutched M62 Eaton
KLZE on T595 throttle bodies
KLDE with t3t4 turbo at 291bhp
B5ZE on evo 8 16g turbo
I've loved Rx-7s since I first saw them, and found them incredibly exotic in appearance.
Why v6
Engine budget - I can't throw 3k into buying a rotary, having it rebuilt and buying all the ancillaries. I love the rotary engine but it's just not for me right now.
Fuel economy - from reading forums and talking to owners it seems sub 20mpg is realistic. It's a quick performance car but that's thirsty. I aim for 30+mpg mixed driving at the same power levels.
The challenge - this is as important as the first point. I've always liked doing my own thing. I prefer to see things that aren't normally done. Bolt on modifying is fun and easy, but it doesn't provide the challenge or push your creative requisites.
Why KL Mazda
Lightweight, compact V6.
Made by Mazda. I like to approach this with a mindset of a V6 option by Mazda.
Bonnet (hood ) clearance.
Available in 200hp naturally aspirated form.
Proven performance 291bhp with an eBay £140 turbo and £120 scrapyard engine with 0.5 bar from my Mx-3 days
I have a lot of parts and spare blocks already and the knowledge of the engine.
Easy to work on.
Reliable. My first K series engine ran for 150,000 miles.
Glorious soundtrack.
Project Rules
The shell must be entirely reversible to rotary if required.
Maintain front mid-engine, rear-wheel-drive layout as far as possible.
Keep weight to equivalent or less than the factory rotary twin turbo.
No butchering the firewall.
No movement of key components including the steering rack.
---------- Post added at 08:59 PM ---------- Previous post was at 08:56 PM ----------
Mock ups
SketchUp
Before I even bought the shell I wanted to make sure the KL was going to fit comfortably. One of the core principles of the project was to maintain the Rx-7s integrity: no cutting firewalls, no moving steering racks. The compact nature of the KL excelled here. It required no modifications to the engine bay nor scoops in the bonnet. To check this I visited the shell, measured up then mocked up the key dimensions in SketchUp, cheap and nasty
Lets get real
I needed to see how things were going to be laid out. I had an old 1.8 K8 which shares the same external dimensions as the KL. I took the crank out and was able to just lift the block in by hand, which made things easy to manage. The result was pleasing. Things were fitting in nicely.
K8 Rx7 v6
One long ass gearbox. The K series block looks tiny!
Adapter plate MDF
The next key step was deciding how to combine my power source to the gearbox. I debated using the KL flywheel VS the Rx7 flywheel and clutch assembly. In the end I decided to keep it simple. Rx7 from the flywheel onwards. I began measuring and drawing up CAD files. After a bit of a learning curve I was ready to make my own MDF prototype.
I printed out my drawings, glued them to MDF and got cutting and drilling. Things seem to be lining up nicely.
K8 Rx7 v6
Still front-mid engine layout, much rejoice. Lots of room for turbo parts and cooling!
I then began mocking up a very crude flywheel to crank adapter.
Thicknesses were modified to maintain all original gearbox clutch and starter function. Maintaining the core principle of no butchering.
The bell housing was scanned to assist accuracy in hole placement.
Sketch up mock was made of clutch interface. I didn't wan't to have to pay twice for manufacture.
Before long I had finished the CAD. The flywheel adapter was to be manufactured in a steel comparable to the forged factory crankshaft. This could not be a point of failure!
The adapter plate was intensely irritating to finalise. Holes clashed, but ultimately it would work out.
---------- Post added at 09:00 PM ---------- Previous post was at 08:59 PM ----------
Adapter plate trial with bell housing:
rx7 kl v6 adapter plate
That was a relief...
And the flywheel spacer fit too! Nice lightweight exedy flywheel for FD3S. Whole clutch/fly assembly weighs in same as standard KL and less than RX-7 assembly.
Changing the v6 from transverse to longitudinal logically implied moving the oil pick up to the new deepest point.
Custom sump to match and fit in the rx7 subframe:
I wanted my intake manifold to flow from the front back. Unfortunately the coolant neck was in the way... so chop and weld time:
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