JC050's 91 Charade G102 - Road & Track

I bought my car in 2006 with 97000km’s, it was in very good condition. It was originally supposed to be a cheap runabout to tide me over until I could get myself another motorcycle (I had just written my trusty old Honda VFR off).

It came with some rubbish 13" tyres, but after upgrading to a set of 14" alloys and a set of Dunlop DZ101’s I really started to enjoy the car and decided it was worth keeping. After that I got an MRT twin outlet muffler, and then just kept going. My objective was always to have a car that was fun to drive on the road that could also do the odd track day, which I finally got round to doing in 2016.

Track Day 2016:


Current Mods:
1.6 Detomaso Block. Decked by 0.4mm
1.5 HE-E Head - Skimmed by 1.5mm, ported.
Approx 11:1 CR, 1mm squish band
Flycut HD pistons
Camtech Stage 2 regrind camshaft - adjustable via offset bush
Megasquirt ECU
MX-5 260cc Injectors
Coil Pack Ignition with custom crank trigger wheel
CAI with K&N filter
Modified Detomaso headers
2" exhaust system with MRT twin outlet muffler
A101 190mm clutch
Strut Brace
Applause vented & slotted front discs
Applause rear discs
Gtti front seats
15" Panasport wheels with 195/50 Bridgestone Re003’s

Some pics below of the various mods:


Flycut Pistons:

Engine, CAI & Coilpack:

Crank Trigger Wheel & Pickup


Regrind Camshaft vs Std


Currently the car probably produces around 120hp at the wheels, I haven’t been able to dyno it recently due to clutch issues (the 1.3 clutch slipped after doing the swap) and then 2nd gear went!

Future Mods under consideration:
Coil overs
Bigger brakes

The ITB’s were going to be my next mod, but blowing 2nd gear has been a bit of a setback. I am waiting on some spare gears to get it rebuilt and back on the road.


Wow, impressive stuff. Just a question, why the HE-E head and not the detom or a HD-E from an applause? Does the 1.5 head boost CR?

Wow. Some time has gone into this. Very impressive. Sorry to hear about gearbox but it’s a common problem with them. I do have a rebuilt gearbox from an f2 if local if interested.

Prior to the HD conversion I ran a HE-E 1.5 in the car for 2 years.

The 1.5 has quite different intake ports to the 1.3 / 1.6 head, and although they are small in stock form I was able to develop a port & bowl shape I liked. As I already had a ported and skimmed 1.5 head, I decided to re-use it, rather than porting and skimming the HD head.

There was some info around previously that mentioned the HC, HE and HD head combustion chambers were different sizes, but my measurements on all 3 came out exactly the same at 42cc.

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1.5 Intake Port - after porting and smoothing.


Ah fair enough, why redo the work when it’s already done. I had heard that the combustion chambers where different sizes but I could never understand why Daihatsu would do thagt/need to change them for an engine of similar capacity in the same family.

Good to know about the capacities, means I’ll have a spare head when get around to my engine.

As all 3 motors (the 1.3, 1.5 and 1.6) have the same bore size and combustion chamber size, but different stroke lengths, Daihatsu vary the size of the piston dome to get the same compression ratio (9.5:1) in all.

So the 1.3 has large domes, 1.5 is smaller and the 1.6 is almost a flat top.


I had actually wondered specifically what differed between the engines to science the different capacities. I had thought stroke as I know is the pistons are interchangeable. Makes sense for them to only change the piston rather than both piston and rod to achieve the same CR.

@viblu, from what i have read, differences are the crank and piston heights, rods and heads are exactly same.

Interesting @Mokeman, I’d love to strip some engines down and actually compare the differences. Maybe I’ll do that when I strip the 1.6 and 1.3 I have. :laughing:

So HC pistons in a HD would raise the compression ratio? or the other way around?\

HC pistons in an HD would increase compression.

HC Pistons in HD - 11:1 Compression
Perfect N/A setup but timing critical
HD Pistons in HC - 7.8:1 Compression
Perfect Turbo setup low - mid boost range

Also HD block is 10mm taller to allow the extra stroke. That’s why you have the different timing belts.


So based on what you said mokeman, a HD block with hc pistons, shaved head and a decked block should be pushing up to high 12s on CR? How much can you take from the head/block before you need to start considering valve reliefs in the pistons?

Camshaft lift, duration and centreline also play a part in whether valve relief is needed on the pistons. It’s not an easy question to answer.

Awesome car. Were the MX5 injectors a straight swap?

Yes they were. They are exactly the same shape as the blue injectors you get on a 1.5 Charade, so they fit right in the standard Daihatsu fuel rail and use the same seals. They are the red MX5 injectors from the 1.8 mk2 model.

As I mentioned earlier in the post I had run a 1.5 motor in the car previously. Even with the 1.5 I managed to get 90% duty cycle with the 180cc HD injectors. I had to get bigger ones before I put the 1.6 in. They now run closer to 70%, which leaves me some scope for the ITB’s I am still thinking about.


Good call about the cams, I was just assuming a performance cam would be installed. Is there argument for lift/duration vs CR? For example having a cam that has huge lift ect may cause you to have a lower CR engine due to clearances, where’s a smaller lift ect cam can allow you to increase the CR? Am I right in saying that? I suppose it’s all about finding the sweet spot.

From the few blokes I’ve known to play with h series, the bare minimum or you will get head gasket issues. Take that with a grain of salt though but they said the head is soft and shitty