On the F50

[StarPD]

After over 45 years of driving some of the highest performance cars in the business, including 10 new special ordered Corvettes, owning 2 G50 Q45s (one a "t" model), and now a 2005 Q45, after my recent 7345 miles cross country trip (22 States), I have developed observations and opinions that may be interesting for those considering buying an F50. My '05 now has 43,500 miles on it, and wears 245/45/18 Bridgestone RE050A Pole Position tires on 18X8 TSW "Kyalami" chrome wheels.

Note however that the 2005 has some improvements that may not be on earlier 2002-2004 versions.

First the Pros:Absolutely GREAT seats (new for '05). I have no *** at all, and they were so comfortable I didn't need any stops between gas fillups, no matter how many miles I drove in one day.Rain sensing wipers; calibrated perfectly and simply terrific in varying weather conditions. No car should be without them.Auto headlights; handy and convenient.Auto headlight leveling for heavy trunk loads is a boon for tripsFlat cornering like nothing else I've drivenNav system; route guidance is incredible, don't know how I ever did without it.Quiet and smooth.Excellent power; passing on hills is a grin maker.Excellent ergonomics and control layout.Low beam headlights are irrefutably the best in the business.Voice operation works, and is great for long highway trips.Audio controls on the steering wheel are great too.Fog lights actually add needed bright light just in front and alongside of the car, a big plus on winding country roads, while the low beams reach out further.Excellent fade free brakes in mountains.Uncommonly short turning radius.Superb climate control, and the dual zone feature is a boon for guys like myself with wives that don't like it "too cold".Separate top console compartment that opens from either side is VERY convenient, and main compartment under it is adequate for most items.Auto up and down for all four windows is handy.Power trunk open and close is a blessing, especially with power opening from the remote ( a button on the trunk must be pushed to power close it to keep people from hittiing others on the head and/or locking their remote fob in the trunk)."Manumatic" auto trans shifting arrangement is intuitive and convenient, no need to look down at the console to change gears manually.Sun visors with extenders and secondary shades is a brilliant idea. All cars should have them.Instrument design and locations are perfect, easy to monitor when driving in all conditions.Turn signal indicators on mirrors is another great idea, something else all cars should have.Compass in rear view mirror is handy for driving on unfamiliar roads, especially at night.

Cons:Extremely excessive understeer, car has to be muscled around high-speed curves and decreasing radius freeway cloverleaf ramps. A real workout in the mountains, and scary sometimes too.Vague overboosted steering lacks decent road feel and feedback.Poor part throttle response at low speeds. Don't pull out to pass a slowpoke in traffic unless you're prepared to floor it and embarass yourself.No illumination of steering controls makes night driving a challenge on unfamiliar roads and inclement weather. My wife's cheap Honda Civic coupe has illuminated steering wheel controls! (Fer cryin' out loud!)No auto door locks (which my wife's Honda also has)Seat controls moved from doors to bottom side of seats; no fun to try to adjust when driving at night in unfamiliar areas, especially in bad weather. A bad move to save a few bucks for Infiniti.No limited slip diff (What could they have been thinking? Traction control and VDC does NOT equal this feature. Poor sound system. Again, the standard audio system in my wife's Honda is better. Bose sucks, and Infiniti would do well to find a QUALITY premium audio company to supply their sound systems.High beams are the worst I've ever experienced in any car. Even with HIR bulbs, they only reach out around 20 yards further than the excellent low beams. FAR too much beam dispersion; lights up the sides of the road great, but doesn't reach out there where they're needed.Fuel and oil consumption is so-so; could be a lot better. Not as good as my old '94 "t" model.Semi-adaptive suspension is a great idea, but the standard setting should be a little softer. Not unbearable, but not up to what a luxury car should have. Considering that there IS a "Sport" setting, the standard automatic setting could be a little softer without sacrificing handling."Dead pedal" is even with the floor and of no use whatsoever.

Most of these items are different from G50s, most are improvements, a few are inexplicable shortcomings. In summation, the later F50s are superb road cars with the exception of the excessive understeer and inadequate high beams. Neither of these are easily remedied, nevertheless, it remains a benchmark for other luxry cars, especially performance oriented ones. All in all, with the exception of the two major flaws, I fnd the F50 to be a quantum leap ahead of the G50. I know one thing. I sure like mine, warts and all.

How about some comments from other F50 owners?

[slybydesignq45t]

I don't own an F50 but that was a good read.

[elwesso]

great read indeed. Maybe I could get you to take a few pictures of your car and we post that on the homepage...

Do you think that the F50 is as good as the G50 was when it was brand new (or for that matter, 3 years old)..?

[StarPD]

great read indeed. Maybe I could get you to take a few pictures of your car and we post that on the homepage...

Do you think that the F50 is as good as the G50 was when it was brand new (or for that matter, 3 years old)..?

Yes I do. In fact, with the exception of the two flaws I mentioned, I think it actually surpasses the G50 when it was introduced. The F50 is a wonderful car, and F-F-F-FAST!As for photos, you betcha. I have pix of "The White Pearl". How do I get them up here or to you for posting?Lemme know.

[mcrews]

George,I have on 02 Sport w 255/45/18 kuhmos on factory rims.Can't agree w/ the extreme understeer. It's not a 3 series BMW. It's a full size sedan. I not sure if maybe it's unique to your car?I realize you have a great deal of experience in other rides.

[StarPD]

George,I have on 02 Sport w 255/45/18 kuhmos on factory rims.Can't agree w/ the extreme understeer. It's not a 3 series BMW. It's a full size sedan. I not sure if maybe it's unique to your car?I realize you have a great deal of experience in other rides.

Thank you for the feedback. I appreciate it.You're right about my experience in other rides. I am much more sensitive to handling characteristics than most people after driving so many VERY high performance vehicles for so many years, including a number of 150+ MPH sedans, like my 425 HP '63 Impala SS 409, 425 HP '65 Impala SS 396, 350 HP '70 Camaro SS, 2-'94 Q45t and my son's '02 M3.

Car is at the dealer right now for oil change and diagnosis of the extreme understeer. I hope you're right, that it's something wrong on my car and not characteristic of all F50s. If so, it can be fixed, and will be a major improvement for me. I'll report back when completed.

Anyone else? I can use all the feedback I can get, and the more opinions, the better I can address the issue.

Thanks guys.

[elwesso]

ill be impressed if the dealer knows what understeer is...

[StarPD]

ill be impressed if the dealer knows what understeer is...

Perhaps with some dealers, but my tech is an experienced Infiniti Senior guy, and is pretty sharp. Besides, I provided a printed MS Word doc with a full explanation of the problem. Put the car in the shop last Wednesday. Tech said it would be around 2 or 3 days before he got to it, as he's rebuilding 2 motors on the floor. I expect to hear from them today or tomorrow. We'll see what happens, and I'll report back here on the results.

[StarPD]

Perhaps with some dealers, but my tech is an experienced Infiniti Senior guy, and is pretty sharp. Besides, I provided a printed MS Word doc with a full explanation of the problem. Put the car in the shop last Wednesday. Tech said it would be around 2 or 3 days before he got to it, as he's rebuilding 2 motors on the floor. I expect to hear from them today or tomorrow. We'll see what happens, and I'll report back here on the results.

Okay, just heard from dealer service department. Disappointing. They find understeer "normal", and cannot duplicate the knock in the steering wheel or the hum/whine coming from somewhere under or in the rear of the car. All suspension and steering components and bushings check out good, and no looseness or play is eveident anywhere in either system.

They advise it needs a wheel alignment, which I'm having them do, and wheel balance, which I'll have Discount Tire do. Engine, trans, and all sensors and controls check out okay, Consult II shows no codes. They are doing an oil consumption test which will take 1,000 miles.

Also, the encounter with the raccoon tore off part of one undercarriage splash shield and tore out the clips on the main one. I'm having the damaged smaller shield replaced (part is $165!), and the missing clips replaced. Damage to the front bumper is separate, and will be done by the body shop when I have the crunch I put in the rear bumper backing into a covered parking post repaired. Raccoon damage to the front bumper appears to be only paint damage, and the black plastic lower grille is cracked. I expect that to cost around $500 or so, in addition to the $775 for the rear bumper repair.

I'm disappointed that they find "nothing wrong" regarding the understeer and the inability to duplicate the steering wheel knock and hum/whine, but will pursue it further as time goes by. At least I'm on record complaining about these things.

[Q451990]

George,

Are your aftermarket wheels and tires the same as OEM in terms of width, offset, etc? There is almost always an unintended consequence when straying from OEM size... I put much wider tires on my Q and got a very distrubing lateral squirm on uneven pavement that didn't show up for about 5000 miles as they aged.

I think it might be worth your while to try to drive some other F50s on your dealer's lot to see if you notice the same understeer issue. That would help you determine for yourself if the understeer is normal.

Heath

[StarPD]

George,

Are your aftermarket wheels and tires the same as OEM in terms of width, offset, etc? There is almost always an unintended consequence when straying from OEM size... I put much wider tires on my Q and got a very distrubing lateral squirm on uneven pavement that didn't show up for about 5000 miles as they aged.

I think it might be worth your while to try to drive some other F50s on your dealer's lot to see if you notice the same understeer issue. That would help you determine for yourself if the understeer is normal.

Heath

Wheels are chrome TSW "Kyalami" 18 X 8, same size and offset as factory optional. Tires are Bridgestone 245/45Z18 RE050A Pole Position, same size as factory optional, and the RE050A is reputed to be the equal of Michelin PS2. I can't see them being different enough to cause such excessive understeer.

Dealer doesn't have any F50s on the lot I can drive, unfortunately. Actually, that's a good idea. I'd like to do that. I'm supposed to pick my car up tomorrow and I'll check that out again though. Thanks for the suggestion.

This is making me crazy. Somehow, I have to resolve it. I don't want to get rid of the car, but.........

[maxnix]

They advise it needs a wheel alignment, which I'm having them do, and wheel balance, which I'll have Discount Tire do.

I'm disappointed that they find "nothing wrong" regarding the understeer and the inability to duplicate the steering wheel knock and hum/whine, but will pursue it further as time goes by. At least I'm on record complaining about these things.

Check with Discount if they have the Hunter 9700. I know dealers are required to have them. Of course, ultimatley it is the operator that makes the difference. That is why I check out the highest 3 recommended Tire Rack installers in my area and use one of them as they tend to be independently owned and operated by the technician. No minimum wage pit monkeys here.

What do tread depths across each tire measure?

Good that you have your concerns on record as it might well protect you past warranty or at least give you legal recourse if Infiniti doesn't pony up.

[Aquaholic]

If you feel a knock in your steering/front end check the "dog bone" looking linkage between the front sway bar and the suspension (behind either of the front tires). There are two rubber bushings that are supposed to hold grease to lubricate the joints - there is no way to add grease.

One of mine went dry and now I have an annoying noise/feeling over bumps.

[StarPD]

If you feel a knock in your steering/front end check the "dog bone" looking linkage between the front sway bar and the suspension (behind either of the front tires). There are two rubber bushings that are supposed to hold grease to lubricate the joints - there is no way to add grease.

One of mine went dry and now I have an annoying noise/feeling over bumps.

I'll check it out.Many thanks for the tip.

[Q45tech]

Understeer is set by designers by having front roll stiffness greater than rear in excess of normal [say 54%/46%] weight distribution.

The 90-96 basic Q had a progressive from 58% to 68% front roll stiffness [3%- 13% understeer] as the front rolled thanks to the initial isolation of front sway bar until the bushings compressed.

The Q45t was 2.5% less [55.5%- 65.5%] due to smaller front bar and addition of a small rear bar [which progressively engaged as its bushings compressed.

The newer CIMA designs had the sway bar more directlly coupled to shock so it wasn't progressive. The Cima do not have a camber compenstation curve [due to McPearson struts] so this adds to the understeer as tires overload.

Stronger [higher load index] front tires is a workable solution.

You really cannot expect dealer technican to be automotive engineers.

[mcrews]

The newer CIMA designs had the sway bar more directlly coupled to shock so it wasn't progressive. The Cima do not have a camber compenstation curve [due to McPearson struts] so this adds to the understeer as tires overload.

Stronger [higher load index] front tires is a workable solution.

You really cannot expect dealer technican to be automotive engineers.

Q45tech,I am running 255/45/18 on stock rimms. 02F50 Sport,(up from 245) since that has a higher load index, would I feel less understreer?

[StarPD]

Understeer is set by designers by having front roll stiffness greater than rear in excess of normal [say 54%/46%] weight distribution.

The 90-96 basic Q had a progressive from 58% to 68% front roll stiffness [3%- 13% understeer] as the front rolled thanks to the initial isolation of front sway bar until the bushings compressed.

The Q45t was 2.5% less [55.5%- 65.5%] due to smaller front bar and addition of a small rear bar [which progressively engaged as its bushings compressed.

The newer CIMA designs had the sway bar more directlly coupled to shock so it wasn't progressive. The Cima do not have a camber compenstation curve [due to McPearson struts] so this adds to the understeer as tires overload.

Stronger [higher load index] front tires is a workable solution.

You really cannot expect dealer technican to be automotive engineers.

So, are you saying that as an alternative to changing front tires for higher load rating than the current 100W, to accomplish the same thing, I could increase front tire pressure to reduce understeer? Or should I increase rear tire pressure as you or someone else recommended in another thread regarding the understeer?

Seems to me that stiffening the front would increase understeer. Where am I going wrong?

With my '94 "t" model, I could actually drift the car around short fast corners with complete control. I don't dare try that with this '05 Q45.

FWIW, I had a 4 wheel alignment performed just this week along with rebalancing of wheels. Changed tire pressures from 34 front and 37 rear to 35 all around. Initial impression seems to indicate that understeer is reduced, to what I cannot make a valid attribution. I'll have to try it on a few decreasing radius freeway cloverleaf ramps to get a better idea of current steering/handling characteristics, and will report back on that. I'll also experiment with changing tire pressure balance if you can advise me which end I should stiffen up with increased tire pressures.

Thanks.

[StarPD]

So, are you saying that as an alternative to changing front tires for higher load rating than the current 100W, to accomplish the same thing, I could increase front tire pressure to reduce understeer? Or should I increase rear tire pressure as you or someone else recommended in another thread regarding the understeer?

Seems to me that stiffening the front would increase understeer. Where am I going wrong?

With my '94 "t" model, I could actually drift the car around short fast corners with complete control. I don't dare try that with this '05 Q45.

FWIW, I had a 4 wheel alignment performed just this week along with rebalancing of wheels. Changed tire pressures from 34 front and 37 rear to 35 all around. Initial impression seems to indicate that understeer is reduced, to what I cannot make a valid attribution. I'll have to try it on a few decreasing radius freeway cloverleaf ramps to get a better idea of current steering/handling characteristics, and will report back on that. I'll also experiment with changing tire pressure balance if you can advise me which end I should stiffen up with increased tire pressures.

Thanks.

Huh.No answer after 3 days.Screw me, I guess.

[maxnix]

I'll also experiment with changing tire pressure balance if you can advise me which end I should stiffen up with increased tire pressures.

Here's the deal. Since the tires are also acting like springs, the spring rate is affected somewhat when you vary tire pressures within their designed performance parameters.

But what affects tire tracking underdynamic loading and not extreme camber change is primarily slip angle. Ignoring camber, alignment and dynamic loading, in the the same tire, increasing load bearing capacity will decrease slip angle. By increasing tire pressure within its designed parameters, you are increasing that tire's load bearing capacity. Hence the advice to increase your car's unloaded pressures in the front till they exceed that of the rear tires. Load changes eveything, and should also change your tire pressures, primarily in the rear in a front engine RWD 4 door sedan.

Now if you have the same tires front and rear at the same pressures (ignoring suspesion geometry and dynamic loading again), increasing the load bearing capacity of all four tires does not change the overall balance, so no change in understeer vs. oversteer tendencies. Staggered wheel fitments can introduce serious compromises and actually increase understeer by fitting wider and higher load capacity (thus lower slip angles) on the rear.

Read Q45tech's earlier posts wherein he discusses slip angles in detail.

[StarPD]

Here's the deal. Since the tires are also acting like springs, the spring rate is affected somewhat when you vary tire pressures within their designed performance parameters.

But what affects tire tracking underdynamic loading and not extreme camber change is primarily slip angle. Ignoring camber, alignment and dynamic loading, in the the same tire, increasing load bearing capacity will decrease slip angle. By increasing tire pressure within its designed parameters, you are increasing that tire's load bearing capacity. Hence the advice to increase your car's unloaded pressures in the front till they exceed that of the rear tires. Load changes eveything, and should also change your tire pressures, primarily in the rear in a front engine RWD 4 door sedan.

Now if you have the same tires front and rear at the same pressures (ignoring suspesion geometry and dynamic loading again), increasing the load bearing capacity of all four tires does not change the overall balance, so no change in understeer vs. oversteer tendencies. Staggered wheel fitments can introduce serious compromises and actually increase understeer by fitting wider and higher load capacity (thus lower slip angles) on the rear.

Read Q45tech's earlier posts wherein he discusses slip angles in detail.

I asked what time it is, and you told me how to build a watch.

So, to reduce understeer, I increase which tire pressures, front or rear?Whew, man, this is like pulling teeth.

[maxnix]

So, to reduce understeer, I increase which tire pressures, front or rear?

By increasing tire pressure within its designed parameters, you are increasing that tire's load bearing capacity. Hence the advice to increase your car's unloaded pressures in the front till they exceed that of the rear tires.

But don't ignore the caveats about adjusting tire pressures to increasing static loading and the shifting of weight distribution.

[maxnix]

Study this.



And this.



From the discussion here.

zerothread/304741

All the simple answers are wrong or incomplete.