F50/VK45 ignition timing.

[StarPD]

I just learned that ignition timing on this series is completely controlled by the ECU, and that no adjustment is possible. Bummer.

Perhaps in the future, hopefully not too distant, some enterprising soul will develop and offer an upgraded ECU for the F50 a la the one offered in this forum for G50. The four stage arrangement would be ideal.

[elwesso]

honestly there is probably much less need for the ECU. Youll notice in G35 the "ECU upgrades" do not give much HP gain, rather they just make it feel like theres more HP by adjusting the way the throttle by wire works.

I would say most of the 340HP vs the VH45s HP comes from the ECU, the OBDII ECUs are more powerful thus they can build in much less safety factors because they can react faster...

So even if we could come with an ECU tune it probably wouldnt give the 30HP we see in G50s.

[StarPD]

Thanks for the reply, Elwesso. I wish there was a simple and relatively inexpensive way to bump HP in my 2005 F50, but after reading your response here, and previous readings of posts regarding the dismal performance gains with the old intake/exhaust improvements, it's not to be.Sigh, I'd sure like to have another 30 or 40 HP but apparently it's just not in the cards. Oh well, looks like I have to focus on handling.

[elwesso]

proabbly the best way to get some more acceleration would be to put a higher numerical gear in the rearend. Your Q has like a 3.1:1, if you could bump that upt o a G50 diff (like 3.5:1) youd be in business!

[StarPD]

Thanks for the suggestion, but I like good fuel mileage too. I'm spoiled.My last Q, a '94 Q45t routinely provided 21 mpg in the city in the summer. On a 7200 mile vacation trip, I AVERAGED 25.5 mpg, incuding all local driving. I took all reguar US highways, through all small towns, with only about 100 miles total Interstate. Now that winter is here, between the colder air and the ether-diluted (For smog control) fuel, it dropped to a miserable 19 mpg.

My new to me 2005 standard Q45 is hard pressed to give 17 mpg, and that's with a lot of freeway driving. I think that with a 3.5 rear end it would be considerably lower, something I wouldn't like too much.

As I said, I'm spoiled. Yes, I want to have my cake and eat it too.But I sure would like another 30 or 40 HP.Not to be, so handling will be my new effort.

My '94 "t" model had a Stillen FSTB, which helped a little, and along with the HICAS, despite body lean in turns, was balanced and tight, with positive feel. While my new 2005 has a FSTB standard, it still is a little more vague despite having 20" wheels. I'd like to do something to firm up the shifts, not much, just a little, and to remove some of the flaccid feel in the steering. I'll be searching for a rear sway bar to remove or reduce the understeer, and possibly some harder bushings in the steering linkage.I intend further to replace the 20" wheels, which I don't like, with OEM 18" Premium wheels, and replace the present Sumitomo tires with Yokohama ES100s. Hopefully, that won't degrade handling too much, but will improve the harshness in the ride while helping steering response. The ES100s are suposed to have great turn-in and overall steering response while tracking true on straights, as well as improved traction.

My '94 "t" was great in corners, and even with the stock BBS forged "lace" pattern 15" wheels and Yokohama AVS DB tires, I used to love drifting it in turns. The new Q corners a lot flatter, but seems more cumbersome. I'd like to sharpen handling and steering response without making it ride like a truck.

I'm open to any suggestions you might have that would point me in the right direction. I suspect that I'm not the only F50 owner that would benefit from tips on improving handling without too much compromise of ride. F50s seem to be the red-headed stepchildren of Q45s, with little in the way of parts upgrades or interest in discovering ways to bring it closer the the G50.

Thanks again.

[maxnix]

1.) My last Q, a '94 Q45t routinely provided 21 mpg in the city in the summer. On a 7200 mile vacation trip, I AVERAGED 25.5 mpg, incuding all local driving. I took all reguar US highways, through all small towns, with only about 100 miles total Interstate. Now that winter is here, between the colder air and the ether-diluted (For smog control) fuel, it dropped to a miserable 19 mpg.

2.) As I said, I'm spoiled. Yes, I want to have my cake and eat it too.But I sure would like another 30 or 40 HP.

3.) While my new 2005 has a FSTB standard, it still is a little more vague despite having 20" wheels. I intend further to replace the 20" wheels, which I don't like, with OEM 18" Premium wheels, and replace the present Sumitomo tires with Yokohama ES100s. Hopefully, that won't degrade handling too much, but will improve the harshness in the ride while helping steering response. The ES100s are suposed to have great turn-in and overall steering response while tracking true on straights, as well as improved traction.

4.) My '94 "t" was great in corners, and even with the stock BBS forged "lace" pattern 15" wheels and Yokohama AVS DB tires, I used to love drifting it in turns. The new Q corners a lot flatter, but seems more cumbersome. I'd like to sharpen handling and steering response without making it ride like a truck.

1.) On AZ CA reject crap-gas? Are you sure you didn't have the display set to metric?

2.) You probably could barely discern that amount of increase.

3.) Going to 18" is a good move, and there are better (lighter and stronger) than OEM wheels if you want to pay. The ES100 is designed for a lightweight car. Read the tire sticky. I also once had Yoko AVS dB.

4.) You have discovered the fundamental suspension design difference between the G50 multilink and the later FY33, y34 and F50 MacPherson strut, besides other calibrations geared towards luxury. Scour the JDM market for springs and shocks.

[StarPD]

Thanks for the feedback, Brian. I'll keep your words in mind as I progress in my quest to improve handling. I'm a believer in an accumulation of small improvements rather than seeking major changes that frequently result in unintended consequences. Regarding tires, I'm especially sensitive to handling and response. Most of the tires I might otherwise consder are too expensive considering the cash outlay I just made buying the car. I'd love to have PS2s, but they're too spendy for me right now, especially in view of their limited mileage. The BFGs and Goodyears are good, but at around $275 each, plus mounting and balancing, road hazard and sales tax, I'm lookikng at near $1400. That's more than I care to invest right now.

Comments from others are welcome and appreciated, especially about tires.

I knew the G50 pretty well, but the F50 seems to be another animal. I really like it a lot though, and if I can just clean up a few minor things, I think it will be a satisfying ride.

[Q45man1]

I have an 02 F50 and replaced the dealer installed Nexen tires with Dunlop Sport Maxx. It is a good summer tires and bought from Tirerack for $125.00 each. It has a load index rating of 100. The downside is the thread life of 20K.

I replaced my stock springs with JDM swift springs. It is a subtle change with slight firm ride. It's still riding with the OEM 18" rims. So far I like it.

[StarPD]

Thanks Q45man1. I'll research that tire.Any comments on it regarding traction, both wet and dry, and turn-in response?

[maxnix]

Well, just remember that tires are the only part of the car in contact with the road, so they determine about 95% of handling/braking limits, provided the suspension is up to as new OEM less normal wear (not worn out). Compromise here, and nothing else matters much. Every old car purcahser faces the upgrade expense to keep up with tire technology. You have a better head start than most if you still have OEM wheels. Sell the dubs to some newb.

I guess that means the $30K (engine delivered to their door) 5.1L Impul VK45DE upgrade is not happening soon? They have an ECU if your rich aunt dies and leaves you in the money.

[StarPD]

maxnix, I am in the process of lookikng for some OEM 18" wheels. I'd like to swap my current 20" one and tires for a good clean set of 2005 Premium Q45 wheels, and plan on buying new ties to go along with them. Problem right now is the money I had to lay out to get the car. Meanwhile, if I keep the wheels and tires, driving on them will reduce their value. Right now they only have around 800 miles on them, and are like new.

I have my dealer looking around for me, and plan on checking with my local Discount Tire store, where I buy all of my tires, and know the manager.Still not sure about the tire I'll use. At first I was going to get the Yoko ES100, but have been advised here that it was designed for light cars. Load rating is the same as OEM though, so that may not be as critical as thought. I'm checking out the Dunlap Q45man1 suggested, and will continue to research tires. I'd like the Goodyear D3 or the BFG equivalent (K2?), but they'll run me around $1200 or $1300 installed, balanced, with road hazard warranty and sales tax, more than I can handle right now.

Still checking and looking, and asking for further tire suggestions from fellow members.

Thanks.

[maxnix]

Read the tire sticky in Infiniti General and all tire/suspension threads by Q45tech. Reading at tire rack will help also.

Joe did have take offs in the past. He has good deals on Nismo and Volk Racing wheels also, but you may have to order. Some of the rear wheels from the Track model Z may work well.

Always spin up and test runout on a used wheel before you purchase. Tolerances are very tight and cruising speed vibrations have been a problem on the F50.

[elwesso]

just remember that all the suspension can do is make sure the tires stay on the ground properly.. The tires still have to do all the work~

[maxnix]

just remember that all the suspension can do is make sure the tires stay on the ground properly.. The tires still have to do all the work~

Exactly! And all new tires are pretty good, and an imiprovement over worn tires.

It is their perofrmance at 10K and up that determines how well constructed they are. And how much money you have spent and will spend to keep them in balance and waring evenly.