full boost in 5th---is it a no-no?

Since I've been on this forum, I stumbled upon a few threads where for some odd reason, some forum members loose their 5th gear. Then I think I've read that this gear is not that strong compared to 2nd or 3rd, and therefore is prone to failure if the 5th gear often sees a lot of boost.

 

Is this true? Should we really avoid full boost in 5th? Cause I noticed that if you're cruising at, say 65mph, and you want to pass in 5th, you can easily reach full boost in that gear in no time. Looking forward to hearing from transmission gurus..

BAC5.2 where are you ?

it happened to me too but I wouldn't be worried though. I think its jsut a small number of pople that this has happend to respectively.

BAC5.2 where are you ?

 

^

 

it happened to me too but I wouldn't be worried though. I think its jsut a small number of pople that this has happend to respectively.

 

Aren't you a bit paranoid though now? Do you avoid boosting in 5th now that you lost that gear once?

bump .

 

Maybe I should PM BAC5.2 to give us some feedback and probably confirm if the 5th gear is indeed weaker than the others.

 

 

Aren't you a bit paranoid though now? Do you avoid boosting in 5th now that you lost that gear once?

 

 

No worries for me. I sold my LGT 6 months ago But i did have the car for 3 years after the 5th gear thing happened to me and i never worried about it happening again. I beat the piss out of my car so i always expected things to break over time.

I'd be more worried about overshooting boost targets and knocking than damage to 5th gear...

Downshift and go.

Downshift and go.

 

I do that sometimes, but there are times I'm just a bit lazy and let the cruise control does its job. And if I hit a long uphill section on the freeway with the CC on, I may reach max boost in no time and stay in high boost for a while, as the CC is trying to maintain speed in 5th.

What the hell kind of hills are you driving up on the highway

What the hell kind of hills are you driving up on the highway

 

. I don't know.. Think about highways in the Rockies or something.

 

 

I guess, when I say 'a while' it could be 5-10 secs. I mean the boost may not exactly stay at max level during that lapse of time, but it'll definitely be high.

you worry too much.

I know. But still, I want to know.

I've held full boost in 5th for over a minute. I wouldn't advise it.

I've held full boost in 5th for over a minute. I wouldn't advise it.

 

So you would not pull the tunnel or Vail Pass in 5th to maintain 60-65 mph?

Is the tunnel or vail pass uphill? I don't know how LGT's are geared, but in my legacy if I were trying to maintain 60mph +/- 5mph I'd probably be in 4th gear, being in 5th I probably would have to floor it the whole time.

Is the tunnel or vail pass uphill? I don't know how LGT's are geared, but in my legacy if I were trying to maintain 60mph +/- 5mph I'd probably be in 4th gear, being in 5th I probably would have to floor it the whole time.

 

7-8% uphill grades easily held at 60-65 mph by cruise control in 5th gear (probably 1/2 or less of throttle would be my guess) with my current mods. When I want to accelerate to maneuver around traffic I DO downshift to 4th. On the downhill runs never less then a 4th gear downshift to hold speed; using the brakes mostly. Also run the smallest (4451, I think) Long Cool tranny cooler.

If you need to hold more than 2-3lbs of boost for more than 10-15 sec, you should probably be in the next lower gear. Can the car do it? Absolutely, but it's unneeded stress.

If you start the hill a little fast speed, the engine will be more in the power band and have a easier time of climbing the hill.

 

5-10 seconds is not that long.

 

Back in the boosted Honda day's the general rule was no more than 15 seconds under full boost. But those cars were never turboed from the factory.

BAC5.2 where are you ?

 

Bump

 

I would still want to know if the 5th gear is 'weaker' than the others.

I'd be more worried about overshooting boost targets and knocking than damage to 5th gear...

 

Agree with this.

However I can climb 10% + grades in 5th just tickling the pedal and maintaining speed, I just wouldn't go WOT for long periods, use a lower gear.

Agree with this.

However I can climb 10% + grades in 5th just tickling the pedal and maintaining speed, I just wouldn't go WOT for long periods, use a lower gear.

 

I agree. Though, the question remains whether that gear is weaker than the others. I am just curious.

I dont think its weaker, just that its the gear that sees the most mechanical stress due to the gearing itself.

I read something somewhere before (I can't remember, I'm old) where they discuss the types of metals used in manufacturing the different gears in an STI six speed. I believe some gears were super high strength steel and some others were of lesser strength. I would venture to say 5th is made of a lesser material.

That's some cold hard facts there.