Trying to understand something on how the CVT works. I'm into modifying my cars for more power. I have a question or two about the CVT transmission and wide open throttle.

From reading, when flooring it for all out acceleration, the rpm needle hovers at high rpm constantly. So, if you were to modify a Fit with a CVT transmission, would it be favorable to modify for best horsepower gains in this high rpm band (Ex: 5500-5800 or so)? Low end torque is important, etc, etc...I realize this and also realize this is not a race car. It is a hobby of mine.

But knowing this information would make the difference in me purchasing a 4-1 header (top end) vs 4-2-1 header for example. Or playing with intake tubing diameter for low end torque vs high rpm. Just trying to get all my ducks in order early on. Thanks!

 

Why not just buy the 6MT and actually drive the car rather than ride along?

 

I agree........plyx is true on a dyno chart where the lines for the tq and hp cross is where the engine makes the best power.

 

? Not following you on this one. ?? I want the CVT, not a manual tranny but that doesn't have anything to do about what I'm asking about.

 

There's a lot of MT snobbery around these parts.

 

Always has been.

 

I learned to drive with a small MT truck and as much as I would love to care it's more work than it's worth.

 

I'm saying, for performance purposes, a CVT will never come close to a traditional manual gearbox, it exists for fuel economy purposes for the average citizen. Nothing more.

 

Oh I follow you. Point taken!

I do a lot of bracket racing at the dragstrip. Consistency is very important however I do like to eek out as much performance as I can. I was told the same thing about autos on my Subaru Outback (back-n-the-day) and my RAV4 *Both Autos*. I just like to go against the grain. Not necessarily to prove otherwise but it feels hella good to do so.

All I can say is we'll see. I go into modding with an open mind and as an observer. You are probably right though. I just don't drive manuals.

 

Got it. I kind of assumed so based on the cars listed in your sig, but one can never be sure. Good luck with your rather unorthodox approach.

 

Bullshit. A CVT can keep the engine in the powerband ALL the time. No cutting the power to shift, no waiting for the powerband. This is why variated scooters and mopeds lay waste to manual ones.

Dual clutch transmissions are already replacing manuals, CVT'S will come shortly after they perfect it.

CVT + turbo = Always spooled.

 

Power is all about torque multiplication. The more you can quickly multiply the faster you'll go.

 

Very astute observation. When you do this multiplication six times quickly through different sets of ratios (6MT), it seems to pull harder than holding WOT and letting the CVT do a constant multiplication using an infinite set of ratios. It must be the direct linkage of the clutch, vice whatever indirect method they use in the CVT.
BTW, my daily driver for the last 17 years has been a Civic HX with CVT. Knowing Honda, I'm positive the new CVT's are more advanced, and could possibly be biased more towards performance instead of economy, but mine sure is boring to drive.

 

So very well said.

Back in the 50's everyone said autos would never have overtaken M/T's. They have today, surpassed, in terms of performance, and some, in terms of MPG!!!

Those who categorically conclude that CVT will NEVER surpase today's M/T's or regular A/T's are locked in the past and uncapable of thinking forward. Technology is way more advanced than what most of us think.

Don't get me wrong. I'm an M/T guy but am not stupid enough not to accept new technology. In other words, am an "old dog who can still learn new tricks".

 

From what I've seen, CVT's put cars just under redline at full throttle acceleration.

That's not the peak in most stock cars powerbands.

Its definitely not the torque peak.

 

But the CVT makes peak horsepower at 6500-6600rpm though right? And the CVT does keep the powerband at or near the red line? Good! I think is the info I was looking for.

 

they already did a DCT Vs 6 speed manual GK5 race in a hot version episode last year.

The DCT loses out horribly on launch (same as the CVT I would imagine) as they arent equipped with a high stall convertor and bog a little off the line so the manual car gets about a 4-5 car head start straight away. DCT also a little slower around the track but not sure if that was due to the DCTs lack of clutch/gear selection (it has 7 gears and paddles so I would assume you could keep the engine in its power band) so perhaps its just the extra weight.

So looks like the autos would lose both in a drag race and in a circut race.

For performace Manual for sure (at least with the GK5) for economy and daily cruising the CVT looks better.

 

when you say DCT over here that usually mean Dual Clutch Transmission so i hope that is not what you are referring to as dual clutch transmissions are completely different than a CVT. as for my experience with my CVT based car...well, i find it interesting to see the differences so far between the Honda CVT on the new Fit and the Note as the lag that someone mentioned on the new Fit when getting off the line is pretty much non-existent on my Note...maybe due to Nissan's implementation having an auxiliary planetary gearset to manage off the line low gear acceleration and high gear cruising? just throwing a guess out there, but i'm keeping an eye on this thread to see what others experiences are, pretty impressed with the new Fit though so far i have to say

 

Wanna be impressed even more??? Go to your neighborhood Honda Dealer and take that TEST DRIVE!!!

 

the hybrid fit has the dual clutch transmission and the race / comparison Hot Version did was between the RS manual and DCT hybrid (Hybrid supposedly with more power when you factor in the electric motors) and the RS was significantly quicker.

I own a CVT GK RS fit (for the past 8-9 months) so have a pretty good idea of how they drive and their short comings compared to a manual.

its not so much lag but compared to a 5000~6000rpm launch like you can do in a manual the CVT is a fair bit slower.