CVT swap? (Into 2005 Civic, replacing 4-spd auto)

[cRiPpLe_rOoStEr]

Originally Posted by CVTCivic

Nissan had some problems with their CVTs from Jatco, but that was a long time ago. I don't know how it's these days. I'm reading a lot through some Honda forums and the CVTs of these days seem very durable and reliable. When there is failure, it's mostly due to neglect and abuse (racing and brake-boosting, not the stuff we Hypermilers use to do a lot). It's important to change the CVT fluid, but that's also important on any other automatic transmission as well.

I'm only familiar with Aisin CVTs fitted to some Toyotas. I don't know about the CVTs fitted to Hondas.

[Ecky]

I've seen various figures quoted but can't say for certain. I have two data points, however:

1) In the G1 Insight, the CVT had an EPA (adjusted) highway fuel economy of 49, while the manual was 60. The manual has slightly taller gearing. Real-world, a manual peaks at ~100mpg @ 50mpg, while an auto will struggle to see above 70mpg at any speed.

2) My wife and brother both have 2007 Honda Fits. Hers is a manual (EPA 34 highway) while his is an auto (EPA 35 highway). The auto has a much taller top gear. Real world, he's averaging mid 30's mpg, while she's averaging low to mid 40's, despite shorter gearing.

[CVTCivic]

With my 10tg generation Honda Civic from 2016, the MT is also more fuel efficient:

WLTP (combined):
6MT: 5,9 l/100km = 40 mpg
CVT: 6,4 l/100km = 37 mpg

EPA (highway / city / combined):
6MT: 42 / 31 / 35 mpg
CVT: 42 / 32 / 36 mpg

[hayden55]

I think its an engineering dream that just isn't gonna happen. A lot of engineering programs in college forced us to use CVTs which are fantastic on paper for max acceleration max efficiency max bsfc but in the real world it isn't. But the problem is that it works for boring laymans who just press the go pedal from stop light to stop light.

[CVTCivic]

@hayden55
Hahaha you have absolutely no clue what you're talking about, seems like you are a real layman lol

[cRiPpLe_rOoStEr]

Originally Posted by CVTCivic

WLTP (combined):
6MT: 5,9 l/100km = 40 mpg
CVT: 6,4 l/100km = 37 mpg

EPA (highway / city / combined):
6MT: 42 / 31 / 35 mpg
CVT: 42 / 32 / 36 mpg

Even though the EPA procedure is somewhat biased to benefit the automatics, it's also worth to remind the US-spec gearing may eventually have some slight differences compared to the Euro-spec.

[EcoCivic]

Originally Posted by Ecky

I've seen various figures quoted but can't say for certain. I have two data points, however:

1) In the G1 Insight, the CVT had an EPA (adjusted) highway fuel economy of 49, while the manual was 60. The manual has slightly taller gearing. Real-world, a manual peaks at ~100mpg @ 50mpg, while an auto will struggle to see above 70mpg at any speed.

2) My wife and brother both have 2007 Honda Fits. Hers is a manual (EPA 34 highway) while his is an auto (EPA 35 highway). The auto has a much taller top gear. Real world, he's averaging mid 30's mpg, while she's averaging low to mid 40's, despite shorter gearing.

Wow that's a big difference! So perhaps I will be getting more MPG than ever once I get a 5 speed. I was wondering if I may lose a little highway MPG compared to the stock 4 speed auto because of the shorter gearing, but it seems that the higher mechanical efficiency of a manual trans often makes up for the loss from the shorter gearing.

I wish I could find the post again, but someone on Civicforums had a 7th gen Civic EX with a 4 speed auto and then traded it for one with a 5 speed manual (the EX 5 speed has very short gearing) and the 5 speed got several more MPG city and highway despite the fact that the shorter gearing had him running at 3200 RPM @ 70 vs the auto's 2700 RPM @ 70. Both cars were coupes with the same D17A2 VTEC engine.

[Fat Charlie]

Your top gear ratio may be lower than an AT's, but since you can actually control your gear ratio and the AT can't... MT FTW.

[CVTCivic]

Originally Posted by Fat Charlie

Your top gear ratio may be lower than an AT's, but since you can actually control your gear ratio and the AT can't... MT FTW.

At least most of the newer cars with CVTs have paddle shifters, do you can influence the gear ratio. But yes the MT will still me more fuel efficient but only if you're driving fuel efficient.

I drive my Civic X with the CVT way more fuel efficient than all the other Civic X with MT I know (forums and fuel tracking sites), because they drive normally and I'm doing a lot of hypermiling. If someone with the same car and a MT does hypermiling, I have no chance with the CVT.

Sorry for hijacking OPs thread and turning it into a basic CVT vs MT discussion.

[EcoCivic]

Originally Posted by cRiPpLe_rOoStEr

Even though the EPA procedure is somewhat biased to benefit the automatics

How exactly is the EPA's testing procedure biased? Do they assume that the driver of the manual trans doesn't know when to shift or something?