Fuel economy and the KL-ZE



  • **So, anyway, I have this long-standing theory that a bigger, more powerful, more torquey (crucially) engine nailed into a car can, with the same type and style of driving, increase the fuel economy of the car. Top Gear kinda showed evidence of this when they ragged a Prius round their track (16mpg) and had a BMW 330 following it as closely as it could (18mpg), but it's not really the same thing.

    Then it struck me yesterday that the KL-ZE in an MX-3 is absolutely the perfect example. Bigger, more powerful, torquier engine nailed into a car.

    So. Anyone with a KL-ZE MX-3 (or any other engine-swapped MX-3 for that matter)… what fuel economy were you getting from the original engine, and what fuel economy are you getting now in normal driving?

    (for the purposes of the question, I'm ignoring other changes like gearing [including wheels], weight reduction and suchlike, though I'm aware they can have an effect - sometimes quite a marked one - on fuel economy)**



  • got 88 miles out of a full tank ( 11gal ) = 8mpg
    that was a full tank at start of track use ( 1hr ) and then journey home. So one tank lasted prob about 1hr40mins.
    And that was of course super unleaded, so yes a Ze is a bit thirsty.

    When using my Ze for work i roughly averaged 15mpg. That was B road driving. So again not economical driving!



  • I found that with the KLZE in it was about 4-6 mpg worse than the K8. Under normal driving and 8-10 under heavy revs.



  • @81017e351e=Garfy1981:

    got 88 miles out of a full tank ( 11gal ) = 8mpg
    that was a full tank at start of track use ( 1hr ) and then journey home. So one tank lasted prob about 1hr40mins.

    **I got 22 (compared to 34 normally) from the K8 on a track day :D

    So… what's the consumption figures for the stock MX-6 ZE? I can't imagine, pulling 600lb less, an MX-3 ZE would be any worse. Surely?**



  • think for some reason ze's always run slightly rich when installed into mx3, mine has always only just squeezed through emmisions.
    Im sure megasquirt would be able to sort this out, find more power and possibly improve fuel comsumption.



  • I was usually on 27 mpg with ZE and probinator chip, and it ran rich as fook.

    Now running megasquirt & coilpacks, and I'll have to get back to you on that! Alot of tuning to go but shooting for at least 30 :)



  • @6df3516931=Garfy1981:

    got 88 miles out of a full tank ( 11gal ) = 8mpg
    that was a full tank at start of track use ( 1hr ) and then journey home. So one tank lasted prob about 1hr40mins.
    And that was of course super unleaded, so yes a Ze is a bit thirsty.

    When using my Ze for work i roughly averaged 15mpg. That was B road driving. So again not economical driving!

    Don't know what mine is on track but its less than that!! How much mileage did you do on track?? I cannot make my tank last a whole day, it gets to just over a quarter of a tank and then I start to get fuel starvation round corners, so i have to go fill it up LOL. K8 was definately more economical than ZE, but no as much fun :lol:



  • I have 2 ze's… My DD - most of my driving nowadays is in the city so I average about 25mpg with a kl36 ecu and 626 (mx-6) tranny (4:11 gearing)... when taking it on the highway I get close to 32 mpg.

    My racecar - this has a mx-3 tranny (4:39 gearing) with a k8 chipped probinator ecu... this gets around 22mpg and about 27 on the highway

    the biggest difference honestly is the transmission between my 2 ze's I'm sure if I had a 626 tranny in the race car I would see improved mileage.



  • when tracking ( brands hatch ) filled it to full at station just up road from it. On last session ( 4 of 4) i had quarter of tank, on constant full throttle it was pulling enough fuel to keep fuel light on but off throttle it filled back to quarter. Did not have any problems and never have with fuel starvation on corners even with fuel light on? maybe you have some crap in your tank?? dirtyfuel filter?
    Have mooneggs/mechanic or anyone else had mx3gulf problem with starvation? without straying too off topic.
    Anyhow in summery the ze could possibly be fairly economical if it didnt make such an addictive redline noise :D
    oh gulf, think track is just over a mile according to site so i looked at youtube video and calculated number of laps x 4 sessions for an average think of 45 miles?



  • @5f0961ebc9=Mooneggs:

    I have 2 ze's… My DD - most of my driving nowadays is in the city so I average about 25mpg with a kl36 ecu and 626 (mx-6) tranny (4:11 gearing)... when taking it on the highway I get close to 32 mpg.

    My racecar - this has a mx-3 tranny (4:39 gearing) with a k8 chipped probinator ecu... this gets around 22mpg and about 27 on the highway

    the biggest difference honestly is the transmission between my 2 ze's I'm sure if I had a 626 tranny in the race car I would see improved mileage.

    **Forgive me if I'm leaping to assumptions, but those would be US mpg? If so, that's incredible (30 average, 38 highway for the daily; 26 average, 32 highway for the track car)…

    (unless you already converted them, given the audience?)**



  • My normal driving ( I enjoy my driving but not too aggressive, atleast not stupidly so )

    I've got 3 mx3's….

    1.6 auto I get 30 mpg
    1.8 I get 28 mpg
    ze with probinator chip (they run richer than kl31 ecu) I get 21 mpg

    No idea of motorway milage as I don't do any.

    I did spend £10 in about 5 mins once in the ZE when I was dragging it at a local racecourse, so it depends on what your doing, but a ZE uses noticably more than the 1.8.

    But on the flipside it is way faster.

    Get a mx-6 gearbox for the taller (better economy) 5th gear.
    Get a straight neck ZE and kl31 ECU.



  • @2660e02263=Famine:

    (unless you already converted them, given the audience?)

    oops a little bit of failure… my MPG (miles per gallon) is US not converted... what exactly is the conversion? do you use kilometers?



  • @eb4b1f7ef4=Mooneggs:

    @eb4b1f7ef4=Famine:

    (unless you already converted them, given the audience?)

    oops a little bit of failure… my MPG (miles per gallon) is US not converted... what exactly is the conversion? do you use kilometers?

    1 gallon (U.S.), 3.785 litres British gallon 4.546 litres Simples :wink:



  • @ba3278be2a=Mooneggs:

    @ba3278be2a=Famine:

    (unless you already converted them, given the audience?)

    my MPG (miles per gallon) is US not converted… what exactly is the conversion? do you use kilometers?

    **Gulf gives the 3 decimal place answers (though technically a US gallon is exactly 3.785411784 litres - a conversion I've been doing so much that I can tap it out on the numeric keypad without thinking :lol: ), but a rough rule of thumb is "add 20% to US".

    So your KL-ZEs run 30/38 (road car) and 26/32 (track car) converted to miles per Imperial gallon. Which is about the same in the case of the road car as I get from my stock K8.

    What octane fuel do you run (and this wll also require a conversion - rough rule of thumb is "take US octane and add 4" - because we use different measuring scales for that too)? I'd hazard a guess you use premium/93 - the equivalent of our super/97-99?**

    @ba3278be2a=Mooneggs:

    oops a little bit of failure…

    **Nah, no failure. Just you happen to use different measuring standards in the US, particularly in motoring, to everywhere else in the world, but then so do we. Most of the world uses kilometres and litres/100km, we use miles and miles/gallon (Imp), you use miles and miles/gallon (US). Most of the world uses metric horsepower (PS/cv/Ch), kW and measures torque in Nm/Kgm, we both use imperial horsepower (hp) and imperial torque (lbft or ftlb). And octane ratings can be anything, anywhere - we use exclusively the RON system, which is retarded, and the US is pretty much alone in using the PON/AKI/Octane number (which, for anyone who cares, is the RON [research octane number - a bench test] + MON [motor octane number - a bench test using real world conditions] all divided by two. Since MON is usually 8 lower than RON, give or take, the average is usually 4 lower and that gives the difference between your octane and ours).

    But it's all good, because I speak American :D Spent some time over there (7 states so far), got married over there and intend to emigrate there by the end of the decade.**


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