Does anyone know if it's safe/not when driving on the highway to downshift from 5th directly to 3rd? I sometimes do this to pass someone on the hwy. faster & in looking for the higher end of the hp/tq curve. The tach will 'pop' from 2.5-3K rpm to 5K-5.5K rpm (which sounds kind nice on the JWT as well)! ;D But will there be excessive strain on the tranny and/or clutch?

Thx in advance for your feedback.

 

Aside from the normal wear of revving up your engine... there should be any problems... 3rd is good up to about 80+ mph at redline.

 

Thx!

 

rev match it and all will be well

 

Oops, I'm a "lurker" in rev matching. Can you offer some pointers?

Thx!

 

Just blip your gas when shifting between 5th and 3rd to raise your revs up to around 4/5K. This will match the revs of the engine and trans when letting out on the clutch. It puts less wear and tear on the clutch.

 

does going from 5 -4 just not do it?

 

it does it fine but everyone with an intake knows that they just "have" to gun it WOT at any opportunity. grrrrrrr i'm addicted........

 

You can easily pass a car by downshifting to 4th gear, but the "in yer face" pass will require a 5 to 3.

Seriously, if you are going 75mph, let's say, downshifting to 4th gear doesn't give you much oomph at all...

 

I wouldn't go from 5th to 3rd at 75MPH.

 

Much appreciated! Yeah, when I downshifting from 5th to 3rd to pass, the growl of my JWT at 4K/5K is a bit addictive (but I also look to tap into the top end of the hp curve).

Thx to all who provided feedback! peace

 

It doesn't make sense only because there is only like 1k more to go before redline.

 

Small correction/addition here 3rd at 6500rpm indicate's a speed of btwn 90-95mph.4th at 6500rpm is good for 130mph.5th gear is a waste as it is good for only 10mph more

 

Stygian;

I think GreenMax is trying to explain double-clutching (something everyone had to know how to do in the "good ol' days" before all manual transmissions had syncros). Professional(non-drag)racers and big-rig truckers have this down to an art. I am neither of the above, but I learned it at high performance driving school many years ago.

Obviously, what you're tring to do is minimize drivetrain "shock" and get max acceleration as well. To do this, you need to have the transmission and engine turning at the same speed BEFORE you complete the downshift. It'll take some practice, but after a while, you'll be able to accomplish the following in less than a second:

1) Shift out of the higher gear into neutral.
2) With your foot off the clutch, in neutral, "blip" the throttle to get your revs just slightly above where they'll be when you complete the downshift.
3) Put your foot back on the clutch and complete the downshift.
4) If you're looking to accelerate, get on the gas pedal. If you want to slow down, leave your foot off the gas pedal.

I tend to use this "technique" as much as possible and the clutches on every vehicle I've owned lasted more than 200,000km. And I tend to drive just a little aggressively

That's my 3 cents.


BTW, Mike @ Superior was blown away when I told him about your post re: clear corners.

Mark

 

Thanks for the info! I think i need to go back to driving school.

{QUOTE]
BTW, Mike @ Superior was blown away when I told him about your post re: clear corners.
Mark [/QUOTE]
Gee, I hope you mean "blown away" in a good way! We're you able to get your clears through Mike?

 

Yes, the gearing is correct, but in terms of usable power, you need 5th to get to top speed. 4th can redline at 130, but the VQ will just be done and out of torque at 120, better off shifting up to 5th to top it out. When driving hard, I tend to shift 3-4 at ~90, 4-5 at `115-120, and wind out 5th. It's the only way, until the VI comes along. Then, you can redline in 3rd and 4th

DW

 

Gee, I hope you mean "blown away" in a good way! We're you able to get your clears through Mike? [/QUOTE]

Yes, he was a very happy guy - I helped him navigate to your post over the phone. He thought it was extremely cool.

It turns out that he lives less than 3km(Kingston & Midland area) from me and even knows the owners of the restaurant where my son works.

He says that the clears should be in my hands (or my son's) by April 15.

Thanks again, BTW.

Mark

 

Well, I think it makes a lot of sense if you are racing. 75mph-90mph punch in third gear is faster than a 75mph-90mph punch in 4th.

 

What you really want to do is rev match - not necessarily double clutch.

All you need to do to rev match is blip the gas to bring you up to the proper rpm for that gear.

For example on my 5th gen, the difference between each gear is about 750 rpms at the same speed. So, at a given speed, 3rd gear will turn about 750 rpms more than 4th and 1500 rpms more than 5th.

You push in the clutch, hit the throttle enough to give you 1500 rpms and then put it in gear. When done correctly it will be seemless - but you'll have to practice. I actually have my blip down to 750 rpms and when I do the 5th to 3rd I blip twice quickly. Works like a charm.

You don't need to double clutch as the synchros take care of everything.

 

I agree that double clutching isn't 100% necessary, but it will save your synchros and clutch a lot of wear and tear and the downshift will be even smoother, if done correctly.

What happens in the method you describe, is that the transmission doesn't get up to the same speed as the engine until after you've made the downshift.

With double clutching the transmission and engine are at the same speed before (or just as) you take your foot off the clutch, so the clutch and synchros have very little load placed on them as the downshift is completed.

Mark

 

I tend to agree with Max Gator, let the synchros do the work. Double-clutching is too much effort for the possibly little decrease in wear and tear on the synchros. I feel like deja vu having discussed this on some other thread. Another thing to consider, the weakness of the maxima tranny, at least the 4th gen Maximas, seem to be the bearings, not the synchros. Nissan seems to have gotten the synchros part right. My original tranny went 120,000 miles. My bearings went. When I replaced it, the original tranny still worked, the clutch was fine, synchros etc. The bearings were just noisy as hell whining in all gears, but they still worked.

DW

 

If you really want to save your clutch, just don't use it. It is very easy to shift the maxima without the clutch.

As for double-clutching - there may be some benefit. I really don't know how much. However, it is not necessarily smoother. When I downshift and rev match correctly, you can't even tell I shifted.

 

... of course it's very easy to shift w/o the clutch, but you are going to be "scuffing" the clutch a little whenever you shift like that. And the synchros and bearings might get a little tired of it after a while...

I think that double clutching and rev matching are probably equally smooth if done correctly, but I'll bet that I could tell that you'd downshifted - unless, of course, you have an amazing amount of soundproofing in you car...or I've gone deaf.

What you may not have considered is that both Stygian and I live in the Great White North (a.k.a. Canada) where 5 speeds tend to get a little "notchy" when it's cold (below 32F), so there are times when rev matching may not be the best choice.

Have a great Easter, Passover, or whetever you care to celebrate this weekend.

Mark

 

2 words: Redline MTL

Redline MT-90 is very popular. I use it. In winter, though, it gets a bit notchier than the normal silkiness that the MT-90 gives. Still not as notchy as stock, but there's a change. MTL is a little thinner, so should suit your climate better.

DW

 

Yep. MT-90 here.