Has anyone actually seen a difference, and with that is it worth it?

 

Here are some specs for those injectors compared to the FWD VQ35:

FWD VQ35DE: 315cc @ 3.5 BAR (FBJC101)
RWD VQ35DE: 335cc @ 3.5 BAR (FBJC100)

Basically you'll run slightly rich if you leave your AFR untuned. If you try to compensate for the bigger injectors by pulling fuel to lean out the mix using a piggyback, you're essentially referencing a different point on the timing map and advancing your timing. You may see slight gains, but nothing significant, unless done in conjunction with other significant mods and AFR adjustment.

 

Well I already have exhaust intake and thermal spacers...i plan on advancing my timing, gutting the IM already....so do you think it would be worth while if did the injectors and got the max tuned with a afr controller? or would it just not be a big enough difference?

 

I think you'd need to see larger increases in airflow in and out of the engine (headers at least, probably a larger TB too) to get any benefit from higher flow injectors. Sort of like carburated engines. A bigger carb is not always better.

 

headers from cattman are in the near future...they make bigger tbs for the 02-03 max?

 

I believe some people are swapping TBs from other vehicles-Range Rovers if I remember right.

 

hmm ill have to look into that....

 

No point in increasing injectors unless your increasing air flow. Period. Say you had ported heads, cams, FULL bolt on, AND a way of tuning it 100%, then yeah bigger injectors would be a good idea. Unless you're Turbo, SC'ed, E85, Nitrous, or Built Motor, leave the larger injectors alone.

The stock injectors can handle 300 whp as they are. VERY few 350Z's have broken that barrier.

 

i dont think it was the TB, i believe it was the MAF

 

I run them in my maxima but i do have more air forced into the engine...

 

25cc injector upgrade won't do anything for you.

It's a matter of tuning which net you the gains.

 

how so?

 

i talked to a shop and they said tuning wont do much...really just restores lost power...the only way its worth tuning a na engine is if its really out of wack.........thats what they had told me

 

can we find any confirm of this?

 

if you just slap the z injectors in your car you will gain nothing except a lot of carbon buildup and kill your precats early. If you are less than 80% duty cycle on the stock injectors there is absolutely no point in upgrading. But if you are in the high revs a lot and the duty cycle is above 80% and they start to heat up, then it makes sense to upgrade the injectors.

 

Have you searched? Search 'LRMAF', there's your confirmation.

 

There's no point in using bigger injectors unless the car is starving for fuel. I'm running nearly all the bolt ons. When I dyno tuned it we had to lean out the fuel mix because it was running RICH. The injectors were providing more fuel than I needed.

I think you'll find that as you add more mods the car will run more rich. If you want to make power get a SAFC and dyno tune the car to add LESS fuel.

Forget about injectors unless you're running forced induction. At that point you'll need bigger injectors than the 350Z.

 

thanks for the useful reply....sick of people saying...have you searched....... no i have not searched as of yet they just posted about it, i never thought about it so i asked if anyone can confirm it, so i apologize that my question invoked you to ask if i have searched.... i asked in my thread to the people who were replying if they can confirm what they said, i dont spend 24 hours a day on a computer so it can be hard to search for everything you want to..with that being said if anyone actually knows it would be nice....sometimes also, people dont know what to search for, and some people dont know what certain acronyms mean....in this case however, it was nice that you posted a search for someone or me to try

 

thanks for the info, i plan on doing a dyno in the spring once the max comes out of hibernation, then after i do a couple more mods i will re-dyno and post the before and after

 

I have them on my car.... Just intake and cat back. it felt a little better pull up top but nothing major. Car doesn't smell rich at all. I can't really see any extra carbon build up on the tips but it's not something I look for. People (Paul and Merlyn) tell me I probably don't feel a gain from the z injectors, it's just lost power that I re-gained from the crappy clogged injectors I had. All I know is that I feel a little bit more in the upper RPM range. I'm sure this didn't help you at all but that's all I got.

 

bringing up a fairly old thread, AGAIN!!!... i have some 350z injectors, im not really looking for any "gains" my mods are I/H/E, block plate, i am getting the p0123 code which is injector1 malfunction IIRC, now i guess its best to replace all the injectors, my car is eating up way more gas and it is sputtering, most time i will have to use 30% throttle to get 10% performance then it all the sudden catches itself and speeds up, any extra tips??? or just pull the IM off and change em and im done???

 

P0123 is a TPS code, not injector.

What other codes are you getting? P0123 should only be set with additional DTCs, which you should fix first.

But yes, the Z33 injectors just drop right in, it's an easy install.

 

when i did mine and tuned out the difference (which was VERY small), I actually turned worse times at the track. If you compare the screens between the z injectors and ours, our screen is a lot more fine which I would expect atomizes the fuel better and maybe makes up for the difference in timing. If you want to go that route for advancing your timing then I would suggest bigger injectors than the FBJC100's

PS: the amount of misinformation in this thread is laughable. If you consider doing this for gains, look into the all-motor N/A tuning links before you believe anyone in this thread

 

Codes were
P0300
P1122
P0057
P0223
P0123

 

what do those mean according to the codes sticky?

 

idk u tell me lol

 

who are you?

 

P0300 - Multiple Cylinder Misfire Detected
P1122 - Electric Throttle Control Performance Problem
P0057 - Heated Oxygen Sensor 2 Heater High Voltage (Bank 1)
P0223 - Throttle Position Sensor 1 Circuit High Input
P0123 - Throttle Position Sensor 2 Circuit High Input

Bad TPS? I dont know 5.5 gens that well though. But I do know that most likely only one of these codes are the real issue. Fix that one and the rest will go away.

 

Diagnose the TB issue first. There is no separate TPS as on the VQ30, it's a part of the throttle motor assembly.

Did the TB sustain any damage at some point? Likely just needs to be replaced, or a harness issue.

 

^^^ its a VQ35... i cant recall anything going bad with the TB, never dropped it scraped it idk... i will for sure check it out... anything i need to do or look for in general???
EDIT: i must add that the spark plugs are probebly 2-3weeks old

 

who are YOU?

(what kind of question is that? what do you want to know?)

 

is there a sc option for 5.5 gen? I was under the impression that was a no go for 5.5?

 

There's also no point in porting VQ35 heads. It was a generic statement.

And you can supercharge anything, it'll just take a little more work than buying a pre-fabbed kit.

 

its a question....you dont post ****....who are you

 

im someone who has a pretty solid knowledge base but doesnt post that often. i mostly read. ive been a member for over a year...

 

Dude why even start going off topic??? are you really that curious to ruin this thread??? anyways back on topic... what should i do to diagnose a TB??? what am i looking or listening for???

 

no offense but the thread is about 350z injectors, not diagnosing a TB

 

If you know there is a sticky... why wouldnt you check it yourself??

Ive been in here every day for around 4 months (when I bought my max) and never seen or heard anything from you... so its understandable somebody might wonder who you are when you just jump in asking random questions...

It doesnt sound like your problems are coming from the injectors... man this is a major hassle I feel bad for you. I would have given up and taken to a mechanic by now... credit card ftw!

 

If you read his post... you would notice that he has 350z injectors and is having problems...

 

Im glad you know how to read lol