Mark 3 Engine design

[mikebore]

The Mk 3 brochure says it has "a brand new 1.3L i-VTEC petrol engine..."

Assuming they don't mean it is not a used one (haha) anyone know what is the difference in engine design in the Mk3? I can find no real info about it.

The Mk2 brochure says it has a SOHC (S for single I assume), and the Mk3 brochure says it has a DOHC (D for double? or direct?...but wasn't the Mk2 direct as well?)

I think the Mk2 had a 16 valve with variable timing, although the hybrid used an 8 valve engine (I think). What about the Mk3? I seem to remember reading that the variable timing gave more power over 3000 rpm.

I found this article but difficult to relate to what is in UK 2015-2016 cars

Thanks for any links or info.

[guest5589]

The article you posted refers to the L15A1 engine that was an option on the 1st Gen Jazz (GD). It was never offered in UK but was available in rest of the world.

As you correctly figured

SOHC = Single overhead cam, can be 8 or 16v
i,DSI = 8V engine
DOHC = Dual overhead cam, 16V engine

The GK engine (3rd Gen Jazz) uses Intelligent Variable Valve Timing and Lift Electronic Control (i-VTEC) + VTC (Variable Timing Control)

Here are some specs of the new GK engine:

1.3 iVTEC Earth Dreams
Power (PS)= 102ps@6000rpm
Torque (Nm)= 123Nm@5000rpm
0-62mph=11.2 seconds
Max Speed=118mph

Specs of old GE Engine

1.3 iVTEC
Power (PS) = 100ps@6000rpm
Torque (Nm) = 127Nm@4800rpm
0-63mph = 11.5 seconds
Max Speed = 113mph

The old engine was not direct injection

[mikebore]

Thanks very much for that!

The only bit that doesn't quite gel for me is that while I had my Mk2 (SOHC) for three years, I always thought it was a sixteen valve engine.

Maybe I am getting confused between extra valves and extra spark plug. Does the Mk 3 have two plugs?

[Paulwhitt20]

The MK 1 DSI ? Had two spark plugs per cylinder.

I thought the MK 2 was an I-vetch. With one spark plug per cylinder. Probably 16 valve.

[guest5589]

Thanks very much for that!

The only bit that doesn't quite gel for me is that while I had my Mk2 (SOHC) for three years, I always thought it was a sixteen valve engine.

Maybe I am getting confused between extra valves and extra spark plug. Does the Mk 3 have two plugs?

Sorry I got that mixed up as I was putting down info for all three engines.  Indeed SOHC engine from GE is 16v I have amended my post. It got a bit confusing because there was a Jazz before the GD so the current Jazz is actually 4th Gen.

[mikebore]

Thanks!

[mikebore]

I have now ploughed through the manual of my Mk3 SE, and found in the Specs section, on page 582, that the engine is described as SOHC, contrary to the brochure which says DOHC.

I am a bit doubtful that the Mk3 has Double OHC. This would be a very significant change and I feel they would have made a bit more of it in the marketing.

I think SOHC and DOHC are both single with the D meaning direct, and Honda have been a bit sloppy about sometimes using SOHC and sometimes DOHC. Just my hunch.

[Paulwhitt20]

Too many TLAs and ETLAs

[guest5589]

DOHC is a standard term for twin cam engines and SOHC for single cam ones.
UK brochure says it's a twin cam

http://hondakarma.com/data/attachment-files/2015/10/91674_Jazz_brochure_2016_v2.pdf?version=1349

[mikebore]

Agreed, so maybe the manual is just a typo, carried through from the Mk2.

If the Mk3 is a DOHC (which it could well be since I see there have been DOHC versions before) it is a bit surprising to me they don't make more if it....but I see that generally they don't say much about engine configurations, just highly technical descriptions like "brand new".

[mikebore]

There seems very little on the UK Honda website about engines, but this link from Honda NZ describing the 1.5 and 1.3 versions is very clear, as is this one from the US.

The manual is just a typo.

[DWF]

I have found that the new 1.3 engine is quite a "two stage" unit with nothing happening below 2,000RPM and then a rapid response from 3,000 on. Also the first gear is a little short I think. Don't tell Honda but, I hit the rev limiter last week while pulling away in a spirited fashion which is something I have never done in my last two Jazzs

[mikebore]

I have found that the new 1.3 engine is quite a "two stage" unit with nothing happening below 2,000RPM and then a rapid response from 3,000 on.

I am still getting used to my Mk3, but it is certainly very different from the Mk2. I am not quite sure how to express it but what you say, plus I have the feeling that the CVT feels more like a conventional automatic, with noticeable change points.

This is consistent with these words taken from this Honda press release:

"For the 2015 Jazz, Honda’s popular, optional CVT is a newly-developed unit delivering better fuel economy and significant improvements to driveability. An all-new CVT control logic was developed specifically for European markets to deliver the direct and linear feeling expected of a manual transmission. This results in vehicle speed matching accelerator pedal position more closely for a more direct feel, while engine speed increases proportionately to accelerator pedal position for a more linear feel.
The CVT’s driveability is given a more natural ‘multi-gear’ feel through the use of new control software exclusive to Europe which simulates seven speeds and provides optimised gear change mapping. Two new additional programmes provide situation-specific enhancements."

The emphasis is mine.

[John Ratsey]

I have found that the new 1.3 engine is quite a "two stage" unit with nothing happening below 2,000RPM and then a rapid response from 3,000 on. Also the first gear is a little short I think. Don't tell Honda but, I hit the rev limiter last week while pulling away in a spirited fashion which is something I have never done in my last two Jazzs

The low end is Atkinson cycle and configured for economy, not performance. The switch over is, I would guess, somewhere between 2500 and 3000 rpm. The CVT version is capable of fairly effortless cruising at 70 mph with the engine well under 2500 rpm.

[VicW]

I have the feeling that the CVT feels more like a conventional automatic, with noticeable change points.
The CVT’s driveability is given a more natural ‘multi-gear’ feel through the use of new control software exclusive to Europe which simulates seven speeds

This is what the '7 speed' option did on the earlier CVT box fitted to the GD/Mk1 and was,in my opinion, a waste of time and money that could have been spent elsewhere.
One of the points of a CVT is that it is completely smooth and seamless in it's function, why make it something it isn't?
Maybe it is to make it more acceptable to the magazine road tester brigade who have never understood the CVT anyway.

Vic.