So I have injen cai, crawford plenum, headers, cats, UR crank pulley and injen SES exhaust.

Last night i beat a civic hatch with a GSR motor, a 240sx with a SR20det motor, but a frigging 2005 stock 350z kept up with me from a roll in 2nd gear about 4K on.

This had me scratching my head WTF.. Do I really need an ECU reflash that bad???? I was thinking the mods say GO, but the stock ECU says NO. Maybe someone can explain this to me.

 

What does the dyno say?

 

I have an 03Z and similar mods: Injen cold air intake, UR crank pullie, Injen dual exhaust, Kenitex Plenum V4, grounding kit, and no cats. I take the car out to the track a few times before and after every mod. I notice a difference everytime. So far I've manage to drop 7-8/10ths of a second of my 1/4 mile times from no mods to all mods. I have no ECU Flash but will consider it if the gains prove to be worth the money or if I'm in danger of BOOooommm.....

Dave

 

Hey Gus.

I will find that out on May 7th, I'll be going to dyno day with the G35 guys.

 

Yea, I notice a big different in butt dyno when a new part goes on. Could just be my head lol.

 

Well the dyno will be good so you can compare apples to apples, with cars in the same dyno and same conditions.

On our dyno days down here we have found that not all 350Z's are the same, we had one with every NA mod known to man and only dynoed 239 while slghlty moded ones were in the 250 range.

 

Did you reset you comp. after your recent installs?

 

Yup did all that. Dyno day will tell alot.

 

As we all find . . . not every Z car that rolls off the factory line was created equal. You could have had a less than average motor versus a better than average one, but hey, didn't the 05s get a little engine tweak? Combine that with the driver factor and that could explain the majority of your concern . . .

G

 

Well it was a good run, i knew i had a factory freak... btw im the "friggen 2005 350z" seriously i thought i was gunna get my *** handed to me... oh well, i still love his car... cant wait to get this baby dyno'd...

 

Here's another variable to throw into the mix . . . although I love my Volks, you're also running 19s. Nevertheless, both cars are quick and it gives you a good excuse to jump on the FI bandwagon

G

 

yea 19s will get ya

 

Ok, so I am a doubter on this hehe, bring out the scales... how much does a 19" volk SF-challenge 19x9.5 with 275/35r19 tires weigh.. and how much does the stock 18X8 (touring model) with 245/45r18 tires weigh. I can imagine the extra 1.5" width of both rim and tire MAY cause some weight gain, but honestly I don't think 1 inch of spoke on those wheels weighs anymore than 1 inch of tire sidewall w/ air, etc. Overall diamater should be staying roughly the same too.

 

keep in mind too that the farther the weight is away from center, the greater an effect it will have

 

also, they will slow acceleration no matter how light they are, they act, basically, like having a lower gear set.

 

Only the Track or 35th Anniversary 6-speed models.

 

This is only true if you change the height of your tires, most people keep the tire height the same by using a lower profile.

On another note if you have a set of 19's and a set of 17's that weigh exactly the same, you will be faster with the 17's, due to the fact that the weight is further away from the hub on 19's. When i went from my stock 18's to the 19's i have now, my gas mileage dropped by about 3 or 4 MPG. Look at cars that get tracked, no one serious about it uses 19's. The difference is significant but i still love my 19's.

 

Yes, you most likely need an ECU reflash. Your car may show decent A/F on a dyno but you need to (if you can) collect timing data as well at the same time. So many people get caught up on A/F ratios alone and although it is important, so is timing and this engine is particular about timing. The ECU reflash would help with both A/F, timing, Throttle body opening and RPM limit. I have very similar mods on my 03 with the addition of cams and TB and I increased my 1/4 top speed by 4 mph after I had my ECU reflashed. It took a couple of fedex trips back and forth to get it right where I wanted it, but once there OMG!! I used TS btw.

 

Not to beat a dead horse, but -
Our local Z club had a dyno day and those with the stock 17 inchers (24 lbs) consistently made more power - modified and unmodified. Compared mine (17in) with the much lighter 18 inch nismos (18 lbs) and there was a decrease in power of 5-6 rwhp. I would expect a similar drop going from 18's to 19's.

This can be attributed to two factors:
1. Increase of combined wheel and tire weight. Even though you've dropped wheel weight, you've most likely increased tire weight. Most of which is in the tread not the sidewall furthest away from the hub.

2. Wide section width tires may give you a better launch but will also create more rolling resistance. This is why you see dragsters with skinny front tires and cars going for land speed records at the salt flats with skinny tires.

I think you did good all in all if it was a track or anniversary model - not so hot if it wasn't.

 

I would have found a corner to cry in if i was that 239 dude. Man thats rough. I hope my Z doesnt have those issues after modding.

~AJ