Sport 1.4i DSI engine improvement question

[guest5056]

hi! I just bought a 2nd MK1 Jazz sport 1.4i DSI. im not sure if the engine in this model is really low powered but i just cant feel any power from them. I mean my Fiat Punto 99' 1.2 feels a bit more punchier than the jazz. by the way I dont have the Fiat anymore but I own another car a 08 Honda civic 2.2 diesel which have some crazy torque. im not sure if im expecting too much from the jazz since im so use to the acceleration of the civic.

[VicW]

The 'Sport' has the same power engine as a normal Jazz, about 88hp, so you are not going to get rocket performance but using the gearbox helps as even the DSI engine doesn't mind being revved.

There is no comparison between the Jazz and a 2.2 diesel Civic !!

Vic.

[culzean]

The GD DSi engine is an 8 valve engine with 2 sparkplugs per cylinder,  it was designed as a frugal engine of medium power and does tend to 'run out of breath' above about 4,500 RPM due to amount of air that can be admitted to cylinders by the single inlet valve per cylinder (ironically this is the point where the Vtec engine really starts to sing). i-DSi is really an engine designed for easy driving about town - it is capable of motorway work,  but not as happy there as the GE i-VTEC.

Take no notice of the 'Sport' or Si designation on Jazz models,  it only refers to styling and not engine power (power is same as 'normal' models across the range).

I have a 8th Gen Civic 1.8 VTEC petrol  and  it is a gem - and no comparison to 1.4 DSi Jazz.  Some misconception here about Diesel 'torque' though - the Diesel engine may have more torque at the flywheel but that is a result of the longer piston stroke (bigger crank diameter) required to get the huge compression ratio required by Diesel engines,  which limits the revs to just over 4K,  the petrol engine revs to 7K.  Actual torque at the road wheels is the same for both engines - it has to be because 0-60 time and top speeds are identical for 2.2 Diesel and 1.8 petrol (that is what the gearbox is there for). 

here is a great article on UK 'Civinfo' site

http://www.civinfo.com/index.php?page=bhp

[guest5056]

thanks for the reply guys. a bit technical for me though. lol! im not really comparing the jazz to the civic as you can not compare a 1.4 petrol to a 2.2 diesel. im just saying that im so used to the punch of the civic that i might be affecting my expectation from the jazz. i know that 1.4 wont give much but like culzean said it runs out of breath about 4500rpm, which bring to my point that i felt that the car is under power. but that is all clear now.

so does that mean that fitting a nice induction kit and a racy exhaust system is just a waste of money for this car?

[JazzyB]

what model of jazz needs is the 1.5 vtec unit as sold in other countries. Why Honda UK won't have it god only knows but I have asked many times.............

[culzean]

so does that mean that fitting a nice induction kit and a racy exhaust system is just a waste of money for this car?

if you want to tune a Jazz get the one with the 1.4 i-vtec engine (GE model)

[guest5056]

I wish I could get another jazz but unfortunately im stuck with this one. I got this from a very good offer with a friend of mine (those that you cant refuse). anyway its not that bad. the engine is good enough for a daily run around car.

[SuperCNJ]

A cold air induction kit will help a little but don't expect any significant gains.

If you are desperate to get some extra power, you could look at bolting on a supercharger. There are companies that have tuned the 1.4 dsi engine to extra a touch more power. But as someone stated above, it really was not an engine that lends itself to be tuned.

What the 1.4 dsi engine lacks, like many other honda petrols is torque at low revs. Honda concentrate their torque in the mid and high rev range to provide a balance between good economy and performance when required. This is further reflected in their vtec engines.

There are ways you help with this but to be honest it'll be too expensive for the little gain you will get.

The cheapest way to help with performance as with all cars is to reduce weight. Don't load your car with any unecessary weight, things some people have done include: replacing spare wheel and jack with tyre weld, remove rear seats, change battery (already quite lightweight - but some have gone for far lighter supercapacitor ones), lightweight wheels etc...

[culzean]

There are ways you help with this but to be honest it'll be too expensive for the little gain you will get.

The cheapest way to help with performance as with all cars is to reduce weight. Don't load your car with any unecessary weight, things some people have done include: replacing spare wheel and jack with tyre weld, remove rear seats, change battery (already quite lightweight - but some have gone for far lighter supercapacitor ones), lightweight wheels etc...

Looked at lithium battery for my motorbike, certainly lighter but at over 4 times the price of the standard Yuasa lead acid to save maybe 300gram a total waste of money (and Boeing Dreamliner airliner fires were caused by Lithium batteries ). Would never willingly replace a perfectly good spare wheel with tyre weld either.  If you are into tuning you need to get VTEC lump and get it chipped - defo cheapest way as the engine is 12/16V as standard (for economy one inlet valve stays closed till about 3.5K then starts to work - making more power but using more fuel - chipping can bring VTEC point to lower revs and increase injector times etc )

[SuperCNJ]

There are ways you help with this but to be honest it'll be too expensive for the little gain you will get.

The cheapest way to help with performance as with all cars is to reduce weight. Don't load your car with any unecessary weight, things some people have done include: replacing spare wheel and jack with tyre weld, remove rear seats, change battery (already quite lightweight - but some have gone for far lighter supercapacitor ones), lightweight wheels etc...

Looked at lithium battery for my motorbike, certainly lighter but at over 4 times the price of the standard Yuasa lead acid to save maybe 300gram a total waste of money (and Boeing Dreamliner airliner fires were caused by Lithium batteries ). Would never willingly replace a perfectly good spare wheel with tyre weld either.  If you are into tuning you need to get VTEC lump and get it chipped - defo cheapest way as the engine is 12/16V as standard (for economy one inlet valve stays closed till about 3.5K then starts to work - making more power but using more fuel - chipping can bring VTEC point to lower revs and increase injector times etc )

I wasn't thinking of lithium batteries - which I suppose if you're desperate you could consider. You may not be aware, but "super capacitors" are really gaining momentum and some have actually built ones that can start a car consistently well. These weigh a fraction of the OEM battery.

But as for lithium batteries, there are different types. Generally Lithium Cobalt Oxide, Lithium Nickel Manganese Cobalt Oxide and Lithium Nickel Cobalt Aluminium Oxide? LiCoO2 is considered less safe at high discharge and gets hot which I suspect could have been used in the incidents that you mention. But in terms of energy density, they are very good.

Tyre weld is fast becoming popular alongside run flat tyres with OEM manufacturers. My car (BMW 1-series) came like that and I think BMW are heading in that direction now to save weight and the need for road side repairs.

As for changing the engine, I agree having a vtec engine is by far the best way to get extra power and is more flexible in turns of tuning. Although staying with an NA vtec engine will only get you so far - as I found with modifying my EP3-R over 7 years. I think the OP just wants a little more power, and especially torque at low revs - not a track animal. So I guess changing the engine is probably not an option... ?

[madasafish]

I'd sell the car and buy something faster.
Cheaper, more effective and insurance will cost a lot less.

(You are going to tell your insurers?  )

And of course, the MOT emissions test will be more difficult with a modded car..

[culzean]

You may not be aware, but "super capacitors" are really gaining momentum and some have actually built ones that can start a car consistently well. These weigh a fraction of the OEM battery.

very aware of super-capacitors (and their limitations) - they have high energy density and OK for storing energy for shorter periods and giving high discharge current for short periods (ideal for starting an engine), and are OK for EV's for handling the regen power or if they are charged very regularly . What they are not good at is storing energy for longer periods, and they have linear discharge characteristics which means that as they discharge their energy their voltage falls rapidly to zero (unlike a normal car battery where voltage drops hardly at all as it discharges).  The ideal combination at the moment would appear to be a super-capacitor for starting and a smaller 'regular' battery for longer term storage.

have also spoken to people who have used run-flat tyres and they all seem to be of opinion that they are 'stiff' and not nearly as compliant as normal tyres (as you would expect as sidewalls and beading have to be strong enough to stay on the rim with no air in them)..   I think the extra <10Kg for a regular spare is well worth leaving in the boot.   

[SuperCNJ]

You may not be aware, but "super capacitors" are really gaining momentum and some have actually built ones that can start a car consistently well. These weigh a fraction of the OEM battery.

very aware of super-capacitors (and their limitations) - they have high energy density and OK for storing energy for shorter periods and giving high discharge current for short periods (ideal for starting an engine), and are OK for EV's for handling the regen power or if they are charged very regularly . What they are not good at is storing energy for longer periods, and they have linear discharge characteristics which means that as they discharge their energy their voltage falls rapidly to zero (unlike a normal car battery where voltage drops hardly at all as it discharges).  The ideal combination at the moment would appear to be a super-capacitor for starting and a smaller 'regular' battery for longer term storage.

have also spoken to people who have used run-flat tyres and they all seem to be of opinion that they are 'stiff' and not nearly as compliant as normal tyres (as you would expect as sidewalls and beading have to be strong enough to stay on the rim with no air in them)..   I think the extra <10Kg for a regular spare is well worth leaving in the boot.   

Hope my last post didn’t come across as patronising… wasn’t doubting your knowledge. Just that not a lot of people know about the advances in super capacitor tech.

The latest supercaps work well as they do retain enough charge (apparently) even after leaving the car unused for a little while which I have to say surprised me, but as you rightly say, they will lose power eventually. So one of the ways is to couple it with say a small LFP battery as a form of back up.

As my wife does a lot of short journeys each day, I actually bought her a tiny lithium emergency battery for her GD which is no bigger than a large box of matches to keep in her glove box, weighs around 250-300g and will start a car many times over on its own. I could imagine manufacturers making an integrated cap based battery that has something like the emergency battery I have bolted on, weighing no more than 1kg total one day. This is probably the beginning of the end of SLA batteries.