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Is upgrading injectors a "requirement"?

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#1
stvegtr

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My car is 2018 Gtr premium 

all stock

 

Is upgrading injectors a "requirement" if I'm just doing:
 

3 inch Catless Downpipes and 4 inch full straight pipe?  (no resonator/ no mufflers)

 

I have no plans of doing any modifications in the future other than full straight pipe exhaust. 

 

Cause my local shop is telling me that it is perfectly ok not to upgrade injectors since its just exhaust, 

there are also many members in my local Gtr club who have changed to catless downpipes WITHOUT upgrading injectors  also (no check engine using armytrix CEL terminator ), the only difference is that, they are running Armytrix full exhaust with mufflers and valves, while for me I have planned to use 3'' Armytrix Catless downpipe and 4 inch full straight pipe. 

 

They have doing this for a long time, but I've read some sources that downpipes will max out stock injectors so I'm confused. 

 

However, I also dont want to change parts unless they are required cause i want to keep my car stock besides exhaust 

 

 

as of now, my car is all stock, no tune whatsoever, turbo boost is also all stock. 

 

I dont join races, but do occasional WOT to redline. Temperature in my area ranges from 85-95F

 

 

 

Thanks in advance

Hope someone can help me decide.


Edited by stvegtr, 18 June 2019 - 03:46 AM.

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#2
5ive

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no u dont need upgraded injectors but u can make more power with upgraded injectors if they it all depends on the air fuel mix ratio and how much boost u run. A good tuner will take care of everything. Some tuners take more risk and go 98 % fuel duty ratio or some like to keep an bigger safety margin. So go get a good tuner, or leave the tune stock and put in cel terminator.

 

greetings,

Robert


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#3
stvegtr

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no u dont need upgraded injectors but u can make more power with upgraded injectors if they it all depends on the air fuel mix ratio and how much boost u run. A good tuner will take care of everything. Some tuners take more risk and go 98 % fuel duty ratio or some like to keep an bigger safety margin. So go get a good tuner, or leave the tune stock and put in cel terminator.

 

greetings,

Robert

 

 

Hi thanks for the reply,

 

actually the stock power is enough for me, I just want loud sound 

 

 

so basically my plan is safe for the car?

3''catless dp with cel terminator/ catless DP with o2 defouler (no check engine), 4'' full straight pipe

no tune, stock everything except for the exhaust set up

 

 

do you know about how much injector duty I'll have? 

 

by the way I do occasional WOT to redline

 

Regards


Edited by stvegtr, 18 June 2019 - 05:09 AM.


#4
5ive

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U have stock injector duty car will run as intended by nissan with injector safety margin as planned by nissan. Only if u go more power u will run more injectors. Your local shop advice is correct. Just be prepared sometimes the mechanic does everything right and still a turbo stud breaks it will take more time so you have to pay more. It's kinda like a force mayor it happened on my gtr.

 

greetings,

Robert.


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#5
Tim

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no u dont need upgraded injectors but u can make more power with upgraded injectors if they it all depends on the air fuel mix ratio and how much boost u run. A good tuner will take care of everything. Some tuners take more risk and go 98 % fuel duty ratio or some like to keep an bigger safety margin. So go get a good tuner, or leave the tune stock and put in cel terminator.
 
greetings,
Robert

  

U have stock injector duty car will run as intended by nissan with injector safety margin as planned by nissan. Only if u go more power u will run more injectors. Your local shop advice is correct. Just be prepared sometimes the mechanic does everything right and still a turbo stud breaks it will take more time so you have to pay more. It's kinda like a force mayor it happened on my gtr.





 
greetings,
Robert.



Robert is absolutely 100% correct, thank ya Robert for giving the man solid advice
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#6
stvegtr

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U have stock injector duty car will run as intended by nissan with injector safety margin as planned by nissan. Only if u go more power u will run more injectors. Your local shop advice is correct. Just be prepared sometimes the mechanic does everything right and still a turbo stud breaks it will take more time so you have to pay more. It's kinda like a force mayor it happened on my gtr.

 

greetings,

Robert.

 

 

 

Thanks alot Robert for the advise :) 



#7
stvegtr

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by the way 

 

which is better for stock gtr?  3" or 3.5" catless dp 
(combined with 4" catback)

are there also differences in sound? 

 

thanks



#8
Guido

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You can probably go on youtube and find some sound videos of different down pipes and exhausts.


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#9
stvegtr

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You can probably go on youtube and find some sound videos of different down pipes and exhausts.

yeah I've watched lots of videos however
cant really tell the sound difference based on videos alone 

I think I want 3.5'' catless DPs 
however, wouldnt it be too much for my car since my car is all stock and will not be getting a tune. 
i'll just be using an o2 defouler. (so no check engine light) 



#10
thehelix112

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Super loud stock power gtr?

But why?

Dave

#11
stvegtr

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Super loud stock power gtr?

But why?

Dave

 

Few days ago, I had installed 4'' full straight pipe (no mufflers/ no resonator) from Y pipe to back

but still on stock downpipes, however, its not loud enough :)

 

 

Saw this video on youtube
https://www.youtube....h?v=WsmlQEyrVBU

is this the sound of 4'' full straight no mufflers w/ Catless Dp?

I mean based from the video, its loud, but not like "super" loud? 

 

Majority of the guys in my local Gtr club runs Catless DP, however, they have mufflers at the back (Armytrix).

A full Armytrix 90mm exhaust w/ Catless Dp is louder than my current set up which is Stock Dp and 4'' straight pipe to the back.  

 

 

Closest one I've heard I think is a guy running Tomei 4 inch with Catless Dp, but Tomei still has small mufflers at the back, its loud but it sounds awesome to me.

 

I actually haven't heard a legit 4'' full straight pipe (no mufflers) w/ Catless Dp before in person. I guess its almost the same sound as Tomei?

 


Edited by stvegtr, 19 June 2019 - 08:50 PM.


#12
Guido

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In my area, there is a city called Seal Beach and when you drive through, there is a sign that says "loud exhausts will be ticketed".  I thought that was funny since so many American muscle cars are loud as shit.  But they have to catch you as well.

 

I like the sound of my stock exhaust.  It sounds nasty enough and it's hard enough to hear in the car as it is with the R888 tires without a louder exhaust.



#13
thehelix112

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In my area, there is a city called Seal Beach and when you drive through, there is a sign that says "loud exhausts will be ticketed". I thought that was funny since so many American muscle cars are loud as shit. But they have to catch you as well.

I like the sound of my stock exhaust. It sounds nasty enough and it's hard enough to hear in the car as it is with the R888 tires without a louder exhaust.

+1.

I switched my midpipe (to one with two mufflers) coz Joe gave me a cracking deal on his old one. Sounds great to my ears.

#14
Guido

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Where in LA are you?



#15
thehelix112

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Where in LA are you?

Westside. East edge of Mar vista/palms. You?

#16
Guido

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I'm in Fullerton and work in Seal Beach.  I daily drive my GTR.


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#17
droptopp

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You can not add downpipes and leave the car on the stock tune. I mean you can, but the car will run like crap.

As others have mentioned you will max out stock injector duty cycle pretty quickly if you are running the proper tune.

Assuming in Orange County you will be running either 91 or E85. If the latter you will need injectors regardless.

If you want to open it up a bit and do not want to tune (why wouldn’t you though), add the Y-pipe and an axle back without mufflers. Can run that without tuning but will run rich on stock computer.

Good luck

Edited by droptopp, 20 June 2019 - 12:48 PM.

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TSM Billet Crank 4.1 w/ CP billet pistons, TSM Elite Prime turbos, TSM Wet Sump Oling upgrade, flex fuel, ETS mid and down pipe, STM titanium axle back, STM race FMIC, ID2000’s, Shep One K with drop gears and all the goodies., DS Axles, Volk Saga 18” 10/12” (MT ET Streets), Advan GT Premium 20” R888. 1450+ hp / 1210+ tq

Old setups : Alpha 9 w/ AMS 3.8, GTX3582R Gen II w/ AMS 4.1 billet crank, GTX3582R Gen II w/ AMS 4.0 big bore billet crank and of course FBO E85.

#18
stvegtr

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You can not add downpipes and leave the car on the stock tune. I mean you can, but the car will run like crap.

As others have mentioned you will max out stock injector duty cycle pretty quickly if you are running the proper tune.

Assuming in Orange County you will be running either 91 or E85. If the latter you will need injectors regardless.

If you want to open it up a bit and do not want to tune (why wouldn’t you though), add the Y-pipe and an axle back without mufflers. Can run that without tuning but will run rich on stock computer.

Good luck

 

thanks for your reply

sorry what do you mean "run like crap"? 

like in what way? 
will the car be slower or temperature issues or other issues? 

 

actually majority of my local gtr club are running Catless Dps No Tune (Using o2 defouler/ CEL Canceller) but the difference is that they have mufflers at the back (armytrix). while mine is full straight. (would that matter?)

 

kept asking them if the car runs well, they said yes.

 

so I'm quite confused.   

 

 

just to clarify:

If i'm on stock tune with Catless Dp and 4'' straight pipe, the injectors will NOT max out, the car can safely run,  but will not run well?
 
If i have a "proper tune" for Catless DP, injectors will "automatically" max out? or can the tuner control injector flow so I wont need to upgrade injectors?  
 

 

thanks 



#19
droptopp

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Tuners can chime in - but rule of thumb is if you swap downpipes you need a tune.

Full decat will throw P0340 cat codes. Which can be eliminated by 02 defoulers as you mentioned.

But you will get bad boost spikes while on nissan oem airflow based boost control

Cobb & ecutek have re-written the boost code for full control for that extra air flow which is expected from adding downpipes.

Edited by droptopp, 21 June 2019 - 08:12 AM.

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TSM Billet Crank 4.1 w/ CP billet pistons, TSM Elite Prime turbos, TSM Wet Sump Oling upgrade, flex fuel, ETS mid and down pipe, STM titanium axle back, STM race FMIC, ID2000’s, Shep One K with drop gears and all the goodies., DS Axles, Volk Saga 18” 10/12” (MT ET Streets), Advan GT Premium 20” R888. 1450+ hp / 1210+ tq

Old setups : Alpha 9 w/ AMS 3.8, GTX3582R Gen II w/ AMS 4.1 billet crank, GTX3582R Gen II w/ AMS 4.0 big bore billet crank and of course FBO E85.




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