Is the alternator belt worth removing for the track? I have no power steering and no A/C already, and I have UDP. Basically there is only one short belt running the UDP and the Alternator. Is the difference worth it? I have a manual fan switch wired (to keep fans open between runs) and I don't want to kill the battery.

 

OH YEAH! The alternator is the hardest thing to physically rotate. It will free up the most power. It's an easy way to shave .05 to .1 in the 1/4 mile. And your car will survive for a couple hours of straight driving if your battery is sound.

Do what I do, wire in a multimeter to the battery source in your fuse panel and keep an eye on it while your at the track. Try to limit the time you leave your ignition ON. I forget what the minimum voltage your motor requires, but it's lower than you think. If it cranks by itself, then you're fine. It's been so long since I've removed my alternator belt and went for a record breaking run.

 

How much trap speed did you gain? Also was it a CONSISTANT .1 gain?

If that is true, this is good news. I am going back to the track this weekend, with slicks, hoping for some low low 13s.

When I ran 13.32 my second best run was a 13.35. The difference is that my best 60 foot was 1.75, and the 13.35 run was with a 1.85 60 foot. .1 on the 60 foot usually gives .2 in the 1/4, so if I had done that run with a 1.75, I might have pulled a 13.15 or so.

So that, plus alternator belt removal, ECU reset (hadn't done it after switching back to VQ35 knock sensor) and some (maybe) cool temps, well... you know what I'm getting at.

 

Don't be so quick to start thinking 12s. It might be setting you up for a disappointment. Just do what you can and accept 13.1s if they come. I say wait until winter when you can race in a 40 degree weather.

Was it a consistant tenth? I don't know. But I'm very sure it's a consistant gain in power! I have never run the 1/4 mile 3 runs before and after my aternator belt removal. But it's a gain in power than can usually be felt on the street in the butt dyno. Which I think to be 2 tenths in the 1/4 mile before you can feel it in the butt dyno. But take that as a grain of salt. I am trying to be conservative here when I say you can shave .05 to .1 at the track.

Just make sure you're water pump is still working. On the VE, it's connected to my PS pump. Otherwise, I would have lost my PS belt a long time ago for the track.

But it sounds like you're serious about those 12s. If so, then you really need to go all out. Get slicks, get rear skinnies, remove carpet, sound deadening, bumper supports, muffler and anything else you can spare. 12s are possible if you go all out!

Check out my mods list for some ghetto track ideas. I've listed all of my mods. I keep nothing secret from those who want to have awesome track times.

 

Rice math alert! haha just kidding.

 

Haha. I try to be very conservative in my estimates. I realize that the faster you are, the harder it is to shave that extra tenth in the 1/4 mile. But weight reduction can be much more useful than removing the alternator belt. I say, do everything all at once and reap the benefits at the track.

 

Heh.. and you laughed at me two years ago when I told you to pull the belt when you got to the track.

 

I don't remember that. I wasn't thinking clearly two years ago.

I started doing this when I remember you posted something about it on the other forum. And you said it's a noticable gain in power.

 

Yup.. then you argued with me on how stupid it was for about two days- that you'd lose power from the ECU not seeing proper voltage... I finally told you to STFU until you went to the track and tried it, and you came back a few days later thinking I shot you in the *** with NAWZ or something.

 

I'm sorry, I don't remember that arguement. I do remember I was concerned about the motor getting the voltage it needed to make peak power. But I am pretty sure now that the motor has no problem making peak power on only 11 volts.

BTW, you got any other ghetto track tips that I can consider?

 

Yeah. As long as I beat 13.32 I'll be happy. Jime ran his best time without Alternator/PS and AC belt.

 

dude, you're the master of ghetto track tips.

now if you needed some road course help, I could help ya there....

 

There wouldn't be issues with the engine overheating or anything, right? I mean, I know the VQ uses a timing chain driven water pump, but it just seems wierd running the engine with absolutely NO belt, just the stupid UDP spinning for no reason.

 

As long as your water pump still works once all the belts are off, you won't have a problem. My water pump is belt driven, so I either have to make my own electric water pump and remove all my belts or always have one belt while I drag race.

Have you considered taking your UDP to a machine shop and have them mill off the ribs that you don't need anymore? I know on the VE crank pulley, the AC rib is the outer most part of the pulley. So if you gut your car and lose the entire AC system, then you have no reason for that extra rib on your pulley. Mill that off and save even more rotational mass. MadMax024 did that on his VE without any problems.

You should be able to beat 13.32 if the track and weather conditions are the same, if not better, than your previous track visit. You really need to pay attention to the weather b/c that can be your best mod if it works in your favor. Just figure up your air density for your previous track visit when you ran 13.32 and then figure up the forcasted air density for the track day you plan on going. It very well may be hotter and you might be just wasting your time. But if the conditions are the same as before or better, then I say do it and go all out. If you're this close to 12s during the summer months, then without doing any other modifications, you can reach 12s just by having colder winter weather.

 

The weather during the day will be pretty much the same (80 degrees), but when temps drop around 7-8 PM, that's when it gets interesting. Back then I ran 13.32, 13.38 and 13.35 around 8:30 PM. Also humidity will be dropping a lot for tomorrow.

Gonna drop the tire pressure some more in the slicks, remove passenger seat and alternator belt, see what it gives. It will take me only about a half-hour to prep the car, and I race all day (two programs, 10 AM to 4 PM and 4 PM to 11 PM).

Would it be beneficial to unplug the alternator AND remove the belt? Or just remove the belt?

If all goes well I'm not going there alone, so you guys might see some videos

 

Awesome! Keep an eye on barometric pressure also. That alone can sway your track times almost a tenth in either direction throughout the day. I always have to figure up all the weather information before I consider going to the track. Usually, I can estimate my track times within 5 hundreds of a second on my very first run of the day. After I get a couple time trials, I can then estimate my track times within 3 hundreds for the rest of the night. But knowing the effects of weather is very important; even when trying to break new records like you are doing.

Unplug alternator? I don't see a reason to do that. Now, removing the alternator completely... that can shave a few pounds! By removing your passenger seat ALONE can shave over 5 hundreds in the 1/4 mile! That is WELL worth it! You need to shave more weight bad!

If you drop the tire pressure too much in your slicks, things can sometimes get a little floaty on the track. Plus, it can actually hurt your trap speed AND your ETs, even though you had a better 60 foot. Just set your car up so that it can launch without a single chirp of the tires. But, you want to have as much pressure in your slicks as possible, but still have great traction. If you race all day long, you'll figure out your optimal tire pressure. Just make sure you get a tire gauge accurate enough to tell the difference between 12.6 and 12.9 psi. A half pound of pressure is a big difference with slicks, especially when you start getting faster. Also, keep a logbook of everything you did to your car when you raced. Write down track conditions, tire pressure, curb weight, tuning info, coolant temp, launch rpm, and any comments you have about that specific run. This will help you when you race your car in the future.

If you launch at a high enough rpm and your clutch holds, then I don't think you'll bog. Good luck!

 

I haven't run without the alternator yet, just the ps and a/c.

 

More bench racing:

According to this my car is making about 260 HP at the crank:
http://www.dsm.org/tools/calchp.htm

If I remove both passenger seat and rear seat (100 lbs) I would need about 4 more hp to run 12.99 with a perfect 60 foot.

I'll shut up now.

 

Just an update on this subject.

I took off the main belt and tried turning the alternator Aaron and it turns very freely on the 3.5, it will even spin a few revolutions after I spin it by hand so I don't think it is much of a drag when not putting out power.

Here is what I did. I found out which wire it is that cuts off the alternator output and put a manual switch on it. When I turn it off voltage drops to 12-13 and when its on it varies between 13.5 and 14.5. There is a noticable change in engine noise and rpm when the switch is turned on and off. So I am just going to switch it off before I run and then turn it back on at the end of the run. I know its not suppsed to make any difference at low voltage but I read a dyno report from somewhere that the guy lost 17 HP because the voltage was below 12 so I am not too encouraged by that. So just to be safe I will leave it connected. I did a couple of runs on a deserted road yesterday with the wideband and there is a noticable difference in the TPS percentage as well as the acceleration (RPM/sec) with the switch on and off.

I will try on sunday at the races and see how it goes.

 

So the butt dyno agrees there is a difference? Can you tell me which wire it is? I'd love to try that for Saturday's race.

BTW, is it a simple switch just like your manual fan switch mod?

 

Mine is a brown one and yes its just a simpe switch, I tired a WOT switch but the only one I had left was N/O and I need a N/C one like for the DR Mod.

From what I see on the 4th Gen drawing its a W/R wire (white/red) that does the same thing. Its not a heavy wire around 14-16 gauge.

If you want to try it quickly just unplug the connector close to the alt, if its the right one you will hear the difference in the idle.

 

On the alternator on my VE, I can easily tell that it's harder to turn the alternator than it is to turn the AC pulley (when AC isn't engaged). Jime, do you find that the alternator spins just as easy as the AC pulley or and idler pulley spins?

 

Its not the same as the idler but pretty much the same as the AC pulley, there is some weight to it but it spins very easily. Not sure if Nissan changed their alternators or not but I do remember you saying yours was somewhat difficult to spin.

 

I didn't mean it was physically difficult to spin. I just meant that I can feel much more resistance in turning the alternator than I do by turning the AC or idler pulley. If I try to spin the alternator and let go quickly, it won't 'free spin' by itself for more than a half turn. But if I spin the AC pulley or idler pulley and let go, then it 'free spins' more than a few rotations.

 

No there is hardly any resistance but the rotor is still turning unlike the A/C so the flywheel effect is there, but once it starts spinning it does free spin a few revolutions after I turn it by hand.

 

Jime, I cut and removed the plastic on the red and white wire that goes into the alternator, then connected a wire from both cut ends to a switch. Now the car won't start.

So I removed the wires and switch, and twisted the red and white wire back together, but it still won't start. Cranks but won't start. Yet, the car is getting power, clearly. The lights work fine, the radio/CD player, the fan, everything works, but it won't start. WTF?

The other day I unplugged the alternator and it started fine, now it just wont.

 

Oh oh, don't sound good. I hooked mine up to a switch and tried it on Sun but after 2 runs each way I think it worked better hooked up. I am getting around 14.5-14.8 volts with it connected and down to mid 12's with it off. Got a new battery, one of those spiral ones from CT and the voltage seems to be higher than a standard one.

 

Any idea what I should do?

 

Having the alternator disconnected should have no bearing on whether the car will start or not. Has to be something other than that. Are you sure there is nothing else that has changed?

Try unplugging the connector and see if that does anything. Other than that I have no ideas.

 

I unplugged it and it didn't change a thing.

The only other thing I did at the same time is install this fuel fitting instead of the 2k2 damper at the end of my fuel rail:

http://www.sx7r.com/fuelfitting.htm

I'll re-install the damper and see if it changes something, but I don't see how this could affect anything.

EDIT: Stupid error, had nothing to do with the alternator. Nevermind, that'll teach me not to work on the car at 10 P.M. with the flashlight on.

Anyway, I plugged the switch and honestly, I don't think there is a difference. Would have to try it on the track though.

 

I bet you guys would gain alot more power if you removed your wheels too.

 

Genius!

What about the engine? It weights 200 pounds, that's .2 right there.

 

I remember the good old days when I removed everything from my car to lose a .1

Everybody called me a ricer but at least I took a stock car down to 16.9 while most people only could get 17.2

Racing NA feels so good. You don't have to worry about when to start the nitrous and about the tranny slipping.

 

More or less, I get a bit nervous when I shift into 3rd sometimes.

 

Removing the brake rotors would be a nice touch as well...

 

I already bolted on 10.2 inch rears that i have

Big day comming soon some times will fall