New (to me) 2005 Q45 questions

[StarPD]

After 105k of relatively trouble free miles and 13 years, I finally had to bite the bullet and get rid of my beloved '94 Q45t. It suddenly needed $7500 worth of work, and wasn't worth it. I spotted a beautiful 2005 White Pearl Q45 with no options, 24k miles and clean at the dealer, and bought it. It has 20" wheels on it (aftermarket American Racing). I immediately changed the oil to my standard, Mobil 1 Extended service 10w30.

As I understand from another thread here, I can have the dealer perform ITB-02048 update on it which will improve performance and drivability. Is that correct for this car?

It drives great, but I have a few issues and questions.

First, it seems to "push" in fast curves. Much more understeer than my '94 Q45t. VDS is "ON". Is this a function of VDS? What can I do to reduce this without greatly affecting the already stiffer than normal ride (due to the 20" wheels and very low profile tires)? Changing tire pressure balance F/R usually has some effect on most cars. Any suggestions regarding that on this one? I'm running 34 psi all-around now, 1 lb over spec.

Second, I am aware of the fuel pump, injector, and MAF issues in my '94. What should I be aware of and concerned about in my new 2005? And what can I do to avoid encountering problems aside from really good maintenance?

Third, I'm a firm believer in flushing the transmission and replacing fluid fairly frequently, like every 30k miles and diff every 60k. This car, as I understand it, has a sealed transmission. Should I change transmission fluid anyway?

What body and engine designations are correct for the 2005 Q45?

BTW, I'm an older guy, but I drive pretty fast, especially in curves and corners. Handling is as important as acceleration performance and throttle response. Any other suggestions outside of factory scheduled maintenance to get maximum life and reliability, and also best performance will be greatly appreciated.

Thanks for any help you guys can offer.

[Mobscene]

Welcome to the board.

I am a Arizona Member also.

Good luck on the tsb. Every dealership said they would NOT do it under warranty and you will have to pay 120 per hour for labor, plus the price of the gas pedal.

[ceningolmo]

I have no answers to your questions... but, welcome to NICO!

[Q45man1]

Welcome to NICO!

The TSB-02048 covers the 2002 Q45 and not model 03'-'06. Yours should be OK. It covers upgrading TCM, reprogram ECU and pedal upgrade.I just had my 60K miles maintenance done and all fluids are flush and Mobil 1 synthetic. Nissan factory transmission oil is the only one to be used. Belts are also checked.

Definitely your's have a firm ride with 35 series tires in place. I'm running dunlop sport maxx with 100 load index and 35psi all around. My ride is lowered with swift springs still ride very smooth.Post some pics and enjoy your Q!

[StarPD]

Thanks for the input.Any thoughts on the understeer?And again, anyone know the body/engine designations for the 2005 Q45?

[ceningolmo]

Body... as in chassis designation? I think F50 is what you are looking for. Original Q was G50, then Y33, followed by F50.

I don't remember on the engine code... I know original was VH45DE, followed by VH41DE. Latest one is VK45? Someone else will know this one.

[maxnix]

After 105k of relatively trouble free miles and 13 years, I finally had to bite the bullet and get rid of my beloved '94 Q45t. It suddenly needed $7500 worth of work, and wasn't worth it.

So $576.92 per annum in deferred maintenance was a deal breaker?

One should budget about $0,15 - $0.20/per mile unless one wants the car to slowly degrade into a doorstop.

Better luck with your F50!

[Mobscene]

Body... as in chassis designation? I think F50 is what you are looking for. Original Q was G50, then Y33, followed by F50.

I don't remember on the engine code... I know original was VH45DE, followed by VH41DE. Latest one is VK45? Someone else will know this one.

Yes it is a VK45DE Engine Code

[StarPD]

Great. Thanks.Now, anyone know engine detail changes between VH45DE and VK45DE outside of HP and torque increases?

[ceningolmo]

Well... everyone knows the VH45DE is better because I own one.

I don't know any other differences though.... but, someone will know.

[reid_houston]

Well... everyone knows the VH45DE is better because I own one.

I don't know any other differences though.... but, someone will know.

Last time I checked, the VK was rated 50+ horsepower higher.

According to the books to get the power, the VK uses cold air intake and light weight but strong titanium valves. VK also has continuous variable valve timing. VK is also paired to a 5 speed auto.

On the converse all the specialist on the forum say friction in the engine was reduced with the use of new piston rings causing some oil consumption. Also no mods readily avaliable for the VK unlike the VH. VK has not been time tested like the VH either.

[elwesso]

Anyone who thinks the VK is superior to the VH is not on expert on either motor thus their opinion should be taken with the appropriate grain of salt! The VK is OVER RATED whereas the VH is UNDER RATED... Thats all im going to say about this. Despite being 15 years older, the VH still remains the KING of Nissan V8 powerplants offered in the US....

To the original poster, your Q45t had a nice setup.. rear sway bar with HICAS and it probably handled better. G50s were blessed because we could get the Q45a rear sway bar and put it on our stock ones, adn that was nice,F50 does not have the same luck. That would take care of the understeer.

What did your G50 need that you HAD to get rid of it???

[maxnix]

The VK is an open deck design much like the VQ.

Both intake and exhaust camshaft timings are adjustable.

Intake plenum is variable.

ECM is OBD II.

Transmission is a lighter duty design.

Valve area is greater on the VH.

[Q451990]

StarPD,

Another major difference on the VK engine vs. VH engine is that the VH used HLA's (Lifters) whereas the VK uses bucket style valve guides that must be adjusted by shimming. According to Q45Tech, Nissan changed to this design to reduce friction - part of the increased HP numbers. His suggestion was that regular good oil changes and quality oil are even more important with that engine. Sounds like you already have that one covered.

I wonder if some of what you're experiencing with your steering issues has to do with the aftermarket wheel/tire combination. I would see if your dealership has another '05 you can drive with an OEM wheel/tire setup. Then you could compare and decide if a change is in order.

Congratulations on your new purchase! The '05 Q is sweet inspite of the differences between our G50 series Qs. I would love to have one, but I'm out of space in my garage!

Heath

[reid_houston]

Anyone who thinks the VK is superior to the VH is not on expert on either motor thus their opinion should be taken with the appropriate grain of salt! The VK is OVER RATED whereas the VH is UNDER RATED... Thats all im going to say about this. Despite being 15 years older, the VH still remains the KING of Nissan V8 powerplants offered in the US....

To the original poster, your Q45t had a nice setup.. rear sway bar with HICAS and it probably handled better. G50s were blessed because we could get the Q45a rear sway bar and put it on our stock ones, adn that was nice,F50 does not have the same luck. That would take care of the understeer.

What did your G50 need that you HAD to get rid of it???

Never stated one was better than the other, unlike yourself. Just stating the facts ma'am! It is what it is...

[BadQ45t]

Sounds like your made a nice purchase. I think the move would be to drive a stock one and compare. I switched to 19" rims and 35 series on my 97' and it handles alot different, the ride is a bit more harse in certain conditions, like harsh expansion joints going onto some bridges, but the handling is improved greatly.

I'd drive either an 05' you can find in that same area and see if you have the same feeling. Also, what kind of tire are they and what is the condition of them???

[StarPD]

My '94 Q45t developed a valve cover leak, needed an MAF, a fuel pump, a an A/C blower motor, new tires all around, had multiple door dings and both front and rear had been kissed by morons who park by sound. Also, the A/C would shift from vents to floor unbidden, and somtimes it wouls stop blowing air but would have a loud arir rushing noise. No one could find this problem. It also needed new plugs, trannny flush, cooling system flush, diiferential oil change, and drivers seat leather repair, plus new drive for drivers eat. The paint was finally going, and primer could be seen on most edges; sunroof, doors, trunk, hood, etc. It was so full of stone chips that it lokied like it had been hit with a 12 gauge from the front. Finaly, the transmission was vibrating and shuddering in 3rd gear.

That didn't count the things that were due to occur thanks to old age. Mileage wasn't high, but here in Phoenix, the sun and heat are hard on cars, even though we don't have a rust problem.

The engine was strong, delivered 20 mpg in the city and never used a drop of oil, but the rest of the car was just worn out. Too bad, because I really liked that car, and my wife loved it. She hated to lose it, but all things must pass.

[SonzofGod]

Do a search on the ITB-02048 update, I believe it is not needed past 03. At least, not the pedal.

NickSonzofGod