[s-hendrix]

Hey everyone first post here and relatively new to Sami/Jimnys. Just curious... I have a chance to get a clean '90 Jimny RHD Kei in great condition with low miles which has been imported from japan. It is one of my dream cars but not sure how the 660 will hold up as an offroader that can still cruise at 100kmh + on the hwy. I was curious if anyone here has one what their experiences are and also if a g13 swap is an option without loads of fab work. I would feel guilty pulling out the 660 but i'd like to be able to take it on the hwy for road trips rather than towing it. Thanks guys!

[J--A--C--K]

With the right gearing for your tyres it will be fine.
Search Hedgepig in the rigs section gwagon started with a 660 turbo in his awsome build.

[s-hendrix]

Awesome I figured it would be the about the same. Just wasn't sure if transmission and Tcase and what not matched up. I'll keep digging and will check out his build.

[J--A--C--K]

viewtopic.php?f=4&t=13839
Warning there will be much suzuki envy.

[Gwagensteve]

s-hendrix, where are you located?

There is no problem holding 100km/h on the highway with a 660. My car was/is silly heavy and it was OK - (not great, but OK) but in a light SWB it won't be a problem - and weight is the key. Have a look at how the Japanese setup their Kei cars - as light as possible.

Power matches a G13, torque is 15Nm down on the G13, but with an upgraded intercooler, small boost increase and opened up dump pipe torque would easily match a G13.

These are a strong and fun motor.

Now some provisos.

There is very little english language support or tech for the F6A, especially in Jimny trim. (the cappuccino variant was sold outside of Japan, so there is better support for that) Parts availability can be a bit of a chore. The guys in the US who import the 4WD carry trucks can help with some engine parts.

These engines work their turbos VERY hard - they are always on full boost, mine used to run 10psi at a constant cruise. In a 25 year old car, you're going to need to consider turbo replacement. There are some other small IHI turbos that can be used, but you're going to struggle to find them outside of japan. I have had turbo failure in my car and none of the turbos I've seen on these cars are very fresh.

The japanese can be a bit lax on servicing their cars and don't seem to see any point in decent air filtration, so it's common to see turbo compressors physically worn from ingesting dirty air.

The 660 car is basically a mix of SJ410 and SJ413 - engine mounts are SJ410, radiator is bigger than SJ413, gearbox is a 5 speed version of the SJ410 box but with a unique bell housing bolt pattern and ratios. The transfer and diffs ran very low ratios to keep highway revs up - my guess is they spin around 4500rpm on the highway standard. - in any case, pretty much all the driveline parts of the car are unique and very hard to source.

The EFI system is very simple - they run MAP only and no oxygen sensor, so they're in open loop constantly. I had problems with fuel pressure in my car and always suffered from terrible fuel economy - I suspect someone had played with the injectors or something at some stage.

They really are great fun but they are also pretty impractical due to the difficulty of getting parts.

As for swapping in a G13 - it would be a fairly involved job, akin to fitting one to a SJ410. Also consider you'll need to delete the EFI fuel pump, the air filter is on the wrong side, instrument cluster would need to be swapped, and then the gearing will be really screwy with the lower revving motor. Engine mounts are completely different.

I'm contemplating building another 660 car - (I've built three, but one was never completed) I like the idea of a crazy light sierra, my thing is really heavy and that's hard on driveline and defeats some of the Suzukiness of the car, but I'd need to get my 660 rebuilt and engine management properly sorted. I have a 1GZZE CT20 turbo which will really wake the little motor up, with predictable results on drivability, but that would suit the silly point of the build.

[vet 180]

I would not swap a G13 in. the 660 is a cool little engine

[s-hendrix]

Gwagensteve wrote:

s-hendrix, where are you located?

There is no problem holding 100km/h on the highway with a 660. My car was/is silly heavy and it was OK - (not great, but OK) but in a light SWB it won't be a problem - and weight is the key. Have a look at how the Japanese setup their Kei cars - as light as possible.

Power matches a G13, torque is 15Nm down on the G13, but with an upgraded intercooler, small boost increase and opened up dump pipe torque would easily match a G13.

These are a strong and fun motor.

Now some provisos.

There is very little english language support or tech for the F6A, especially in Jimny trim. (the cappuccino variant was sold outside of Japan, so there is better support for that) Parts availability can be a bit of a chore. The guys in the US who import the 4WD carry trucks can help with some engine parts.

These engines work their turbos VERY hard - they are always on full boost, mine used to run 10psi at a constant cruise. In a 25 year old car, you're going to need to consider turbo replacement. There are some other small IHI turbos that can be used, but you're going to struggle to find them outside of japan. I have had turbo failure in my car and none of the turbos I've seen on these cars are very fresh.

The japanese can be a bit lax on servicing their cars and don't seem to see any point in decent air filtration, so it's common to see turbo compressors physically worn from ingesting dirty air.

The 660 car is basically a mix of SJ410 and SJ413 - engine mounts are SJ410, radiator is bigger than SJ413, gearbox is a 5 speed version of the SJ410 box but with a unique bell housing bolt pattern and ratios. The transfer and diffs ran very low ratios to keep highway revs up - my guess is they spin around 4500rpm on the highway standard. - in any case, pretty much all the driveline parts of the car are unique and very hard to source.

The EFI system is very simple - they run MAP only and no oxygen sensor, so they're in open loop constantly. I had problems with fuel pressure in my car and always suffered from terrible fuel economy - I suspect someone had played with the injectors or something at some stage.

They really are great fun but they are also pretty impractical due to the difficulty of getting parts.

As for swapping in a G13 - it would be a fairly involved job, akin to fitting one to a SJ410. Also consider you'll need to delete the EFI fuel pump, the air filter is on the wrong side, instrument cluster would need to be swapped, and then the gearing will be really screwy with the lower revving motor. Engine mounts are completely different.

I'm contemplating building another 660 car - (I've built three, but one was never completed) I like the idea of a crazy light sierra, my thing is really heavy and that's hard on driveline and defeats some of the Suzukiness of the car, but I'd need to get my 660 rebuilt and engine management properly sorted. I have a 1GZZE CT20 turbo which will really wake the little motor up, with predictable results on drivability, but that would suit the silly point of the build.

Thank you so much Gwagensteve for the comprehensive info! I have been doing tons of research and it has been difficult tracing down much of anything about this car. I hope you don't mind me using you as a resource when issues on the car arise.

As for me, I am in the US. My name is Shannon and I am 28. I have owned all sorts of trucks/cars and a RHD Jimny has been one I've been keeping an eye out for some time now. Turbos are nothing new to me so swapping that out will be no problem at all. I tend to be pretty mechanically inclined but I am less experienced with 4x4's so still have tons to learn. By no means do I have any plans to turn this into a mudder or rock crawler but I will use it for minor off road use like going to the river and stuff. I would like it to be stable at highway speeds so any recommendations on a suspension setup are welcome here. I ride a 106cc 2 stroke scooter regularly so I am not afraid to travel slower than everyone else on the road but I don't want to be so slow that I cause accidents so 60mph will be a good goal. Does it stress the motor to run 60mph for extended periods of time? In most cases it wouldn't be for longer than 5-10 minutes since my work commute is about 7 miles away from home but there are other places i'd like to take it so with that in consideration there will be times i want to take it further. I tend to be good at hoarding parts so i will continuously search for a spare turbo and jump on one when i find it to hold onto until the time comes for me to need one. Any other parts that need to be replaced frequently that i should keep an eye out for? Im happy to see that you have had luck squeezing some extra power out of these motors I may not need it but i'm sure i'll want it. If it is a sacrifice for lifespan (pretty much any power increase is) I will avoid it. I would like to make this sucker last as long as possible. Maybe down the road i'll consider a motor swap but for the time being I will keep the 660.

I believe yal have the most impressive Zuk forum and I will continue to be active on here. I will update yal when the car arrives so that yal can see it.

[s-hendrix]

OK so interesting development. Found out the Jimmy is a 1989 550cc. I got them to drop the price quite quite a bit and am still getting it. Any big differences between the 550 & 660? Liability issues to expect or recommended mods?

[Gwagensteve]

There's nothing in it - the change from 1989 to 1990 saw a change in Kei class rules - capacity increased from 550 to 660cc.

I don't believe there are any other significant differences. Obviously power and torque are slightly lower in stock form.

There's no problem with relatively extended highway driving with these motors. They are a fully engineered factory model - the engines are tough and last well. The biggest issue will be the condition of the motor and turbo after 26 years. The exhaust side of these motors is restricted (that's both wastegate, turbine housing and manifold) to limit horsepower and increase low rev responsiveness. There's little flow left at 4000rpm. As a result, the exhaust side runs hot - it will glow red after even a few minutes on the highway. It's OK - they all do that - but it is alarming initially. Letting them idle down after a prolonged run and keeping good oil up to them is wise.

I'll explain a little more about Kei - power is capped by government regulation at 67hp or thereabouts (it's changed a touch through the years) but torque is completely unregulated. 67Hp is easy to make with an atmo 660cc motor - the turbo is there to fill the torque curve out. As such, the turbos are tiny and spool boost <3000rpm in stock form. However, by 5000rpm they're out of flow, so from 5000-7500rpm the motors are pretty slack and doughy in throttle response. The challenge with a power increase is keeping the boost threshold at a sensible level, especially with the lower total RPM potential of the SOHC/2valve F5A/F6A. I owned a cappuccino - with DOHC and 4 valves per cylinder, these motors will spin to 9000rpm, but the stock turbo really won't permit it. I have bene for a ride in a Cappuccino that was making 180Hp. The boost threshold was jus over 5000rpm and the car ran 26psi of boost. The transition onto boost was pretty violent so while the numbers are there, the power delivery is a nightmare for a 4X4 application.

Suspension? Old Man Emu - just buy a complete kit with the softest available springs.

In relation to long term ownership - I wouldn't swap away from the 550/660cc motor. I would keep your ear to the ground, and keep in contact with the guys bringing the Carry trucks into the US. Keep on the lookout for an F6A DOHC motor (cappuccino) these are a much, much nicer motor than the F5A SOHC, or a K6A. The K6A is still in production in Japan and is a DOHC 4 Valve per cylinder all-alloy motor with timing chain and knock sensing. These motors are much more refined. They were used in the Samurai body shape with coil springs from 1996 onwards and are still used in the Jimny body shape now. Getting hold of one of those motors will be the business. The Carry trucks coming into the US have the non-turbo version of this motor, so parts are available locally to you.

The turbo is an IHI RHB31. As far as I am aware, the F/K series motors are the only application for this turbo. Upgraded versions of this turbo are available from Suzuki Sport. The next IHI turbo up the tree is an IHI VF33 - it's the small turbo on the Subaru Legacy B4. These will unlock loads of power, but, predictably move the boost threshold WAY up. I sourced a pair of CT20 turbos from a Toyota 1GGTE 2.0litre 6 cylinder for the motors I was working on, but they needed rebuilding and I never pursued it, but one of these will flow about 90hp of air in stock form which is ideal. Exhaust manifold will need to be custom.

Obviously, engine management will need to be addressed with any replacement turbo.

Be very mindful of ignition timing and fuel quality. With no 02 sensing or knock sensing, these motors will detonate if they get hot or are too advanced. Feed it the best fuel you can get and keep an ear out for detonation.

In relation to the rest of the driveline, I'd swap out parts for USDM Samurai parts as you encounter issues. There's no kudos in running the narrow track Kei axles etc. Swap in Samurai axles and gear them 5.12 or 5.38 using front Tracker ring and pinions - then you can buy repair or upgrade parts locally. Likewise, if you have trouble with the (unique) transfer, swap it out for a Samurai transfer with 6.5 gears in it - don't waste time trying to find the JDM 660cc transfer parts, you'll drive yourself mad.

Keep the car light and the revs up and you'll have happy times!

Steve.

[s-hendrix]

Gwagensteve wrote:

There's nothing in it - the change from 1989 to 1990 saw a change in Kei class rules - capacity increased from 550 to 660cc.

I don't believe there are any other significant differences. Obviously power and torque are slightly lower in stock form.

There's no problem with relatively extended highway driving with these motors. They are a fully engineered factory model - the engines are tough and last well. The biggest issue will be the condition of the motor and turbo after 26 years. The exhaust side of these motors is restricted (that's both wastegate, turbine housing and manifold) to limit horsepower and increase low rev responsiveness. There's little flow left at 4000rpm. As a result, the exhaust side runs hot - it will glow red after even a few minutes on the highway. It's OK - they all do that - but it is alarming initially. Letting them idle down after a prolonged run and keeping good oil up to them is wise.

I'll explain a little more about Kei - power is capped by government regulation at 67hp or thereabouts (it's changed a touch through the years) but torque is completely unregulated. 67Hp is easy to make with an atmo 660cc motor - the turbo is there to fill the torque curve out. As such, the turbos are tiny and spool boost <3000rpm in stock form. However, by 5000rpm they're out of flow, so from 5000-7500rpm the motors are pretty slack and doughy in throttle response. The challenge with a power increase is keeping the boost threshold at a sensible level, especially with the lower total RPM potential of the SOHC/2valve F5A/F6A. I owned a cappuccino - with DOHC and 4 valves per cylinder, these motors will spin to 9000rpm, but the stock turbo really won't permit it. I have bene for a ride in a Cappuccino that was making 180Hp. The boost threshold was jus over 5000rpm and the car ran 26psi of boost. The transition onto boost was pretty violent so while the numbers are there, the power delivery is a nightmare for a 4X4 application.

Suspension? Old Man Emu - just buy a complete kit with the softest available springs.

In relation to long term ownership - I wouldn't swap away from the 550/660cc motor. I would keep your ear to the ground, and keep in contact with the guys bringing the Carry trucks into the US. Keep on the lookout for an F6A DOHC motor (cappuccino) these are a much, much nicer motor than the F5A SOHC, or a K6A. The K6A is still in production in Japan and is a DOHC 4 Valve per cylinder all-alloy motor with timing chain and knock sensing. These motors are much more refined. They were used in the Samurai body shape with coil springs from 1996 onwards and are still used in the Jimny body shape now. Getting hold of one of those motors will be the business. The Carry trucks coming into the US have the non-turbo version of this motor, so parts are available locally to you.

The turbo is an IHI RHB31. As far as I am aware, the F/K series motors are the only application for this turbo. Upgraded versions of this turbo are available from Suzuki Sport. The next IHI turbo up the tree is an IHI VF33 - it's the small turbo on the Subaru Legacy B4. These will unlock loads of power, but, predictably move the boost threshold WAY up. I sourced a pair of CT20 turbos from a Toyota 1GGTE 2.0litre 6 cylinder for the motors I was working on, but they needed rebuilding and I never pursued it, but one of these will flow about 90hp of air in stock form which is ideal. Exhaust manifold will need to be custom.

Obviously, engine management will need to be addressed with any replacement turbo.

Be very mindful of ignition timing and fuel quality. With no 02 sensing or knock sensing, these motors will detonate if they get hot or are too advanced. Feed it the best fuel you can get and keep an ear out for detonation.

In relation to the rest of the driveline, I'd swap out parts for USDM Samurai parts as you encounter issues. There's no kudos in running the narrow track Kei axles etc. Swap in Samurai axles and gear them 5.12 or 5.38 using front Tracker ring and pinions - then you can buy repair or upgrade parts locally. Likewise, if you have trouble with the (unique) transfer, swap it out for a Samurai transfer with 6.5 gears in it - don't waste time trying to find the JDM 660cc transfer parts, you'll drive yourself mad.

Keep the car light and the revs up and you'll have happy times!

Steve.

You sir are a fountain of knowledge. I can't begin to thank you for your help and patience. I've never encountered someone this helpful with your knowledge so much thanks.

Im not even sure where to begin to address your points.

I did a bit of searching for Old Man Emu and didn't see anything specifically for this year model of course searching in the US market might pose a challenge but i'll keep looking. Suspension will be my first and only mods for awhile only because I think all cars should be enjoyed with the stock motor for a period of time to get a feel for you car and find problems, likes, wants etc.. to gain a solid understanding of what to mod rather than just slapping stuff on.

I am familiar with turbo'd vehicles so paying attention to KR and what not is nothing new thankfully. Also i'll run 93 octane as i had in my current vehicle.

Thanks again for everything and i'll keep you up to date. I believe the car is shipping out tomorrow and should be on my doorstep Wednesday or Thursday!

[Gwagensteve]

Suspension for any year Suzuki samurai will fit your model.

Steve.

[s-hendrix]

Gwagensteve wrote:

Suspension for any year Suzuki samurai will fit your model.

Steve.

That's even better news! Thanks dude!