Why did infiniti skimp on the differntial and transmission?

[Infinitiguy19]

When Infiniti was building the first gen Q45 why did infiniti use Viscous Limited slip and a OK but not great transmission?

The differntial from what I have read is not the best and is some what weak and HP eating, From what I read the VSLD can't take much of any beating is only good for daily driving.

Why didn't Infiniti use a clutch type differntial or any other for that matter?

The transmission from what we all know could be better its just that the TCU is slowing it down, But Infiniti should have had an option for a 5 speed.I know though that Infiniti made a Luxury sports car but part of a sport car is a 5 speed usually.

Why not build a better stonger transmission or have the option for a 5 speed?

To me it seems like they put a great deal of money on the engine and interor and skimed on the above two.

Flame if you want because its been a long time since I was flamed.

[F1SportsFan]

Just be glad you have at least some kind of LSD!

M45 = No LSD.

[Infinitiguy19]

What kind of differntial do you have?

[Jesda]

I agree, but the Aisin 5-speed on the LS400 was bad enough to make me dump the car. I don't own a Q45 now for fuel system annoyance reasons.

My ideal luxury car looks like a Cadillac, has the interior of an Audi, is powered by Nissan, has seats from a Lexus, and handles like a BMW. Parts would be as cheap as a Lincoln. I'm not asking much.

[sijoko]

When Infiniti was building the first gen Q45 why did infiniti use Viscous Limited slip and a OK but not great transmission?

The differntial from what I have read is not the best and is some what weak and HP eating, From what I read the VSLD can't take much of any beating is only good for daily driving.

Why didn't Infiniti use a clutch type differntial or any other for that matter?

The transmission from what we all know could be better its just that the TCU is slowing it down, But Infiniti should have had an option for a 5 speed.I know though that Infiniti made a Luxury sports car but part of a sport car is a 5 speed usually.

Why not build a better stonger transmission or have the option for a 5 speed?

To me it seems like they put a great deal of money on the engine and interor and skimed on the above two.

Flame if you want because its been a long time since I was flamed.

You would be hard pressed to find luxury cars with LSDs in them. Most rely on the traction control system to do some of the things that an LSD would do.

The reason that Nissan went with the viscous LSD is because it is doesn't need adjustment and it is not obtrusive.

The trans is a weak spot only because of the soft shifts but what do you expect from a luxury car. Any decent trans shop can fix the shifting issue for you by upgrading the valve body.

The trans gear ratios are another issue altogether, but if you have enough power you can get away with even 1 gear. So, IMO, if you turbo your car, you won't feel the effects of the gearing as much.

[Infinitiguy19]

Great responces all of you, That was kind of what I was looking for but I would like to have Q45tech share his imput on this one too.

[maxnix]

I would like to have Q45tech share his imput on this one too.

If you had read his previoius posts, you would not even have asked such a DA question.

[MinisterofDOOM]

You would be hard pressed to find luxury cars with LSDs in them. Most rely on the traction control system to do some of the things that an LSD would do.

The reason that Nissan went with the viscous LSD is because it is doesn't need adjustment and it is not obtrusive.

What I find curious is that Nissan did BOTH. TCS and LSD don't seem like systems that interact in a positive way. At least not the super-basic TCS that Nissan uses. Seems to me like TCS is best used with open diffs where the rear tires can be allowed to rotate at different enough speeds to maintain traction through turns. No slip, but still a difference between the two tires. Maybe Nissan's system wasn't smart enough to know the difference (wouldn't surprise me considering how crude it is).But with an LSD, under much power both tires will want to rotate at the same speed (meaning one is going to slip). And that means that TCS is going to restrict the whole axle to the best possible speed of the tire with the least traction. It's not "even" and it doesn't contribute to consistent SPEED in the car. Just consistent traction since you're going far too slow for one tire to break free and just slow enough for the other.

I DETEST the Q's TCS system. Even in winter. All it does is restrict available power without asking the driver first. It takes control of throttle away from the driver. It is UNSAFE. Imagine accelerating into heavy traffic into a tight but manageable gap. Moving at a good speed, you try to slip cleanly into the opening. But a rear tire hits a slick spot and BAM there goes your power thanks to "traction" control. Car behind you has to hit his brakes to avoid hitting you, and the moron behind him probably rear-ends him. All this comes courtesy of your car's view that it is smarter than you. If you had no TCS intervening, the spinning tire would slip for a moment (STILL providing some thrust!) and then regain traction and you'd be off. Minimal slowing, thanks to the LSD allowing the opposite tire to maintain power.

I'm extremely glad the Q's TCS OFF switch actually turns it off unlike many other cars where it only pretends to turn off until it once again decides it knows better than the HUMAN driver.

The trans gear ratios are another issue altogether, but if you have enough power you can get away with even 1 gear. So, IMO, if you turbo your car, you won't feel the effects of the gearing as much.

Tall ratios CAN be nice with enough power. when you have 4 gears and 3 of them are "viable" you're in a good spot. Of course, that assumes the trans controller is smart enough to pick the right gear and know what you're trying to do. THAT was Nissan's big weakness with their 80s/90s transmissions. They're some of the dumbest transmissions I have experience with. They delay on power-downshifts and often pick the "wrong" gear. Their more recent offerings are MUCH better (I quite like the 5 speed auto in my dad's '04 Maxima). Much more "transparent" and better at guessing what I want it to do. With the Q and the '93 Max I have fallen to manually shifting the car because I'm sick of waiting for it to keep up with me. This is why I want a manual trans in the Q so badly. I want the car to do what I want instead of messing around with inferior automatic programming.

[Infinitiguy19]

What I find curious is that Nissan did BOTH. TCS and LSD don't seem like systems that interact in a positive way. At least not the super-basic TCS that Nissan uses. Seems to me like TCS is best used with open diffs where the rear tires can be allowed to rotate at different enough speeds to maintain traction through turns. No slip, but still a difference between the two tires. Maybe Nissan's system wasn't smart enough to know the difference (wouldn't surprise me considering how crude it is).But with an LSD, under much power both tires will want to rotate at the same speed (meaning one is going to slip). And that means that TCS is going to restrict the whole axle to the best possible speed of the tire with the least traction. It's not "even" and it doesn't contribute to consistent SPEED in the car. Just consistent traction since you're going far too slow for one tire to break free and just slow enough for the other.

I DETEST the Q's TCS system. Even in winter. All it does is restrict available power without asking the driver first. It takes control of throttle away from the driver. It is UNSAFE. Imagine accelerating into heavy traffic into a tight but manageable gap. Moving at a good speed, you try to slip cleanly into the opening. But a rear tire hits a slick spot and BAM there goes your power thanks to "traction" control. Car behind you has to hit his brakes to avoid hitting you, and the moron behind him probably rear-ends him. All this comes courtesy of your car's view that it is smarter than you. If you had no TCS intervening, the spinning tire would slip for a moment (STILL providing some thrust!) and then regain traction and you'd be off. Minimal slowing, thanks to the LSD allowing the opposite tire to maintain power.

I'm extremely glad the Q's TCS OFF switch actually turns it off unlike many other cars where it only pretends to turn off until it once again decides it knows better than the HUMAN driver.

Actually on the issue of the TCS, I drove today in 30* weather with about 6+ inches of snow (Of course I only drove on the parts that were recently plowed, Lucky for me I had a plow infront of me ) But I owe my life to y car seriously . I installed my Micheline X-Ice tires today but still they were useless compared to TCS.

With out TCS I would have had to drive about 15 MPH, But with TCS I was able to drive 30 MPH (The road was empty and I didn't do anything stupid).

But really I think Infiniti desinged TCS for snow and rain but ecpecially for snow.

Trust me TCS is a life saver and it works with cruise control.

But I tried to get up the hill with TCS off and it was nearly imposible with out making a scene.

Trust me TCS rocks and for those that want to speed or have "fun" disable it at your own risk.

I LOVE TRACTION CONTROL.

[qship96]

I agree, traction control on the Q is essential in snow/ice and extremely helpful in the rain.....with over 200,000 miles of experience behind the wheel of my Q with traction control, it has saved me plenty of times on wet roads and made driving on snow/ice passable using only all season tires.I would not own a Q without traction control, period.

[Infinitiguy19]

Exactly, what other car can you find for a decent price (If properly maintained) that has the control of a Q45?

Honnestly the tires were useless with the TCS, But I will admit I don't have the experince or a veteran driver so obliously TCS is a must for me and other new or safe drivers.

Honestly i don't feel safe in any other car, And I would'nt buy a new one because they are too porly built, So one more reason to restore and maintain these fine engineering marvels.

[Infinitiguy19]

I was going to make a new topic but I thought why spam NICO?

Q45Tech says that the 1990-1993 Q45 transmission combined with a 1997-2001 Q45 Differential will in a way equal out to 4:11 Differential.

Is the 1997-2001 Q45 differential in anyway better made to last longer than the 1990-1996 Q45 differential?
Modified by Paul Wall at 8:57 PM 3/3/2010

[qship96]

How much longer do you want? both my transmission and diff are still going at almost 247,000 miles.

[Q451990]

I can see an argument for the transmission being a weak spot - but the differential? It's pretty much bulletproof with regular fluid changes. You mention that it may not withstand extra abuse from boost, etc. - but that's not the designer's problem.

As for the transmission, a M/T in a non sports car sedan is simply not profitable. How much demand is there for the m/t in the I30 and G35? Sadly, not much.

Try to keep in mind that what was cutting edge 22 years ago when the Q was designed might not be as impressive these days... Compare the engineering of the Q to similar 1990 model cars, and it was lightyears ahead.

Heath

[maxnix]

I don't think any of the BMW models avaialble with MT exceed 5% of sales for that model.

Much different in the 60's and early 70's when they were introduced. All 4 cylinder and most I6 had manual 4 speed.
Modified by maxnix at 10:10 AM 3/4/2010

[1991q45]

you know some sports cars does'nt come with a manual transmission. imo a transmission thats built right can handle just as much as a 5spd can.

i have 161 k on my baby and the lsd still work's.i love the fact that this car does'nt get stuck in the snow. don't like the fact that when you press the gas the wheel spin you kinda go sideways.

and the previous owner must've have done some transmission work because the shifts are firm and sharp as hell.

ministerofdoom i dont know if you were trying to be funny but that story was funny

[paranoidjack]

I agree, but the Aisin 5-speed on the LS400 was bad enough to make me dump the car. I don't own a Q45 now for fuel system annoyance reasons.

My ideal luxury car looks like a Cadillac, has the interior of an Audi, is powered by Nissan, has seats from a Lexus, and handles like a BMW. Parts would be as cheap as a Lincoln. I'm not asking much.

Oh man, I think I'm going to take a beating for this one...

http://www.hyundaiusa.com/buil...nesis

[paranoidjack]

I can see an argument for the transmission being a weak spot - but the differential? It's pretty much bulletproof with regular fluid changes. You mention that it may not withstand extra abuse from boost, etc. - but that's not the designer's problem.

As for the transmission, a M/T in a non sports car sedan is simply not profitable. How much demand is there for the m/t in the I30 and G35? Sadly, not much.

Try to keep in mind that what was cutting edge 22 years ago when the Q was designed might not be as impressive these days... Compare the engineering of the Q to similar 1990 model cars, and it was lightyears ahead.

Heath

or better yet, compare the 90 Q with ANYTHING from 1978 -80 on those same points. Good luck!

[Infinitiguy19]

Oh man, I think I'm going to take a beating for this one...

http://www.hyundaiusa.com/buil...nesis

But I am sorry if I worded it wrong. But I am looking to see if the FGY33 rear differential is a s good as the G50 rear differential?