Re: New Cruze Diesel Going For 50+ MPG? MZ4 Transmission May Have .61 6th Gear
.
The diesel Cruze automatic uses the M3D (9th gear = .62) transmission, the manual Cruze diesel uses the MZ4 (6th gear = .61) transmission.
.
50 miles a gallon could really bring notice to Chevrolet, and it's new Whisper-Diesel models. I have to admit I am really looking forward to a test drive.
.
Yes.... although there are different and 'tougher' EM concerns that all ( Gasser and Diesel ) must overcome going forward which make MPG 'harder'.
The 'new' 6MT ( MZ4 ) with the 0.610 final gear / sixth gear - and the accompanying 3.65 final drive is not an unusual thing with regard to either number together, or separately for a Six / Six + speed MT. We also need to keep in mind - all the other ratios are often, considerably lower especially to no surprise, first gear.
The new Nine Speed CAT with the top gear / eighth gear of 0.620 X a 3.17 final drive does stand out along the lines of what you suggest with regard to other Cruze combos.
But perhaps .... not as much or just for that purpose as some might assume - compared to outside of Cruze / Cruze type and class.
( Just going to skip all other greater than Six FWD ATs currenty offered of whatever type - to keep this manageable.)
With the larger gear spread compared to any and all other CAT types Sixes..... and with a TD in front - all that spread has to be well, spread around.
So a small but nonetheless significant 'amount' goes on one side of the (gear times final drive) six speed range and then, a bunch of gears and spread within the same (gear times final drive) bandwidth but shifted around by the final drive, and then yes, a distinctly taller add-on for the shorter / 'taller' 'highway' end.
Grossly over simplifying .... which is less a sin here for looking @ FE then other..... well sorta' on a first pass anyway.... you have;
....'basically' within acceptable difference, a 7th that equals the old 5th ( 1.00 x 3.17 V. 1.00 x 3.14 ) , an eighth that acts as bridge and is just a
little more sporty than the old 6th
when final drive effects are considered and then finally, the 'new' 9th of 0.620 - which really corresponds nicely to what a more modern but also not maxed out for FE - group of modern MTs provides.
Here,
6MT Gasser ( 3.818 - xxxx - 0.614 ) X 3.65
6MT Diesel (
3.550 - xxxx - 0.610 ) X 3.65
Not a whole lot of difference - all could be considered inside of normal Gasser versus Diesel range and or 'generic tuning' range.
_____
6CAT Gasser ( 4.449 - xxx - 1.00 - 0.742 ) X
3.14
9CAT Diesel ( 4.690 - xxx - 1.00 - 0.750 0.620 ) X 3.17
So looking @ top gear times final drive ( but still ignoring all the other that matters - like the Torque Converters in the ATs - which is 'ok' because you just assume they are locked - even if designed and equipped with constant slip ) you get;
6MT Gasser = 2.2411
6MT Diesel = 2.2265
6CAT Gasser = 2.32988
9CAT Diesel =
1.9654
Big difference for the Nine SP CAT versus
all the rest.
One other thing - the Nine Speed CAT is likely to have identical or very close to identical gear ratios in all other applications although as always, Torque Converters and Final Drives can and will vary - even if less so than in the past especially for the TCs.
