Greasy Gabe

I have a 2003 350z that I’ve done a decent bit of work to. I took it out to Rockingham drag strip for a test and tune event. Each run a had I was getting around 14.2-14.8. Which isn’t bad but should be quicker. My shifts were on point and quick, my fastest runs where when I would dump the clutch from 2500-3k rpms, and my slowest runs were when I would slip the clutch. Keep in mind this is a 1/4 mile prepped drag strip.
here are the list of mods that would effect my 1/4 mile time
1. Kenetix intake manifold v2 (the aluminum one)
2. test pipes and cat back (stock headers)
3. z1 cold air intake
4. wide body running 285/30r20 rear (the 20s weren’t super heavy maybe 23 pounds. I recently got new wheels though. They are 19s and I am running 295s on them, haven’t done a run on the new wheels yet)
5. z1 clutch and light wheighs fly wheel (full face clutch)
there are other mods but these would be the ones to effect acceleration. The car is definitely making less in the low end and more in the top end because my 1/8 mile was about a second slower than stock z times, but I was stuck getting the same 1/4 time that a stock z would.

so what do you all think it could be? Maybe how I’m launching? Maybe lack of back pressure? I am on stock tune as well so keep that in mind. Could it be my gear ratio running bigger wheels? Idk let me know what y’all think it could be and what could fix it. (I’ll try to add a video if I can find it) the video is of me dumping not slipping, and it was my fastest run. 14.2

DarkZ03

iTrader: (11)

All of the above, you aren't making as much power as you should because you've changed too much for the stock ECU IMO.

My fastest fun with some mild bolt-ons was 14.1 on track V1 wheels (light AF), so depending on your engine health I'd say you are where you should be.

Greasy Gabe

thanks for the info, this my about getting a tune, nothing crazy just want the car to know the mods I’ve done to it so it runs right.

OldManZ350

iTrader: (23)

A dead Stock 2003 Nissan 350Z, right from the showroom with a Pro Drive will go 13.90's all day long

Drag Racing is not easy to do well..........

Street Tires will not do good at all on the drag strip, no matter what you do. At your power level a MT ET Street Drag Radial would help you a Lot! you do need to go big so a 275/50/15 is the size, and you'll need some 15" wheels to mount them on.

You ET is slow likely because of the launch and a slow 60 ft time. What is yours? you need to be in the 1.80's of faster.

A good way to see if you car is making the power you want is the MPH thru the traps. this need to be on a good run without any mis shifts and stuff.

I've beed drag racing since the 1970's

Read my Sign

If you are serious about drag racing and what help, PM me.

Sincerely,
TimRod

iideadeyeii

iTrader: (6)

Post a time slip.
I don't believe that intake manifold adds any power non-boosted
The flywheel helps, but the heavier tires does not(adding ~3lbs per side)
Your gear ratio wouldn't change with that tire size. It's exactly the same diameter as stock

DarkZ03

iTrader: (11)

It's documented on here with a pretty long back and forth with myself and a few other members. They found the car to be faster on it and ANY DE making over 300whp NA has that manifold on it (outside of Sasha's or Micheal's cars).

bealljk

iTrader: (13)

Heres what I see -
Gotta get tuned with those mods is the biggest issue … I suspect your engine is making less power than stock without a tune

if you can go back to 18” wheels or the absolute lightest wheels that still give you a respectable traction patch … the rotational mass makes a difference (especially on a NA car).

What Tim said in that drag racing / launching / running the car down the track isnt easy and take experience, trial, error, and the ability to repeat what works best.

I wouldnt so much compare your times to other z times or other participants but rather compare them to your previous sessions - look to make improvements each time you go.

Other areas of insight - do your best to remove as much weight as you can from the car - especially the front half of the car … you can remove weight from the rear but you’re only decrease your ability to hold traction. Consider starting the night with 1/4tank of fuel. Weight reduction can be a drug and become addicting … so tread lightly.

Assuming youre running on DOT tires, consider droping air pressure in your rear-wheels to a sensible PSI - I would go down to 30psi and see how the car does. Theres many reason this ‘could’ provide benefit (increased traction patch, small diameter wheel, etc) but I would no go below 30psi on DOT tires. But try 30psi, 35psi, and 40psi and see how the car does.

I usually pop my hood between runs to get as much heat out of the engine bay. The DE plenum is a solid chunk of aluminum and holds heat and heat is the killer of performance.

Its not back pressure you want … it’s exhust scavenging and exhaust pulse resonation that assist with power gains from exhaust modifications - but seeing that you’ve already done exhaust work I would not mess with it.