Injector Change Poss Prob??

[S15_Spec_R]

I have just got a set of Nismo 740's to replace my Nismo 550's. I was told that its a case of plu and play, is this true (does the injector slide out easily or do I need a tool). The other thing is My Apexi ECU and PFC needs to be told about the change, so if I put the 740's in will the car still run fine?

Am I entitled to have the software and connection to my Apexi ECU with my own hardware of course.

The 550's have only been in for under 1000 miles. Just want some guidance on swapping them over and that the car will stil run until I get the ECU updated.

Thanks, Keith

 

[sushiming]

shouldnt be a problem with the ecu after a remap

the injectors have a bolt which hold them in place...i cant remember what size tho either a 8,10

nismo dont do 550 only 555 just wanna check with ya i know HKS do 550 ?

 

[S15_Spec_R]

Cheers for reply Shu, they must be 555's then (I wasnt paying much attention to the garage as there were oilcoolers, relocation, fmic other electrical and defi stuff going in). I know theyare nismo 55sumthing

So the bolt holding the bar across the inj is all that needs removing and the inj is just pull out? Its not clicked inand wil need force?

I will remap once the 740's are in but my concern is that I will have to drive it but the ecu will think its running the 555's - dont want overfuelling or under if you know what I mean.

 

[sushiming]

u will have to remove the intake mani to get to the injectors...

 

[gunner93]

S15 Spec R

Whats the reason you are upgrading to a 740cc?

 

[S15_Spec_R]

S15 Spec R

Whats the reason you are upgrading to a 740cc?

Well I have a shopping list (prob like everyone else)which includes a stroker kit so in essence I want to be up around 400hp mark. My PFC shows inj duty as upto a max of 93% at 1bar of boost so I assume 555's are not going to cope with my remap to 1.2bar (this is what I wanted initially) but Hyeline have let me down. Need to find someone with a rolling road to remap that are good at it too.

I also got the 740's cheap so it could not be passed, why is it overkill Gunner?

 

[S15_Spec_R]

u will have to remove the intake mani to get to the injectors...

Really, gawd dang it. Is this straight forwardish (gaskets need to be replaced or sensors etc?)

 

[sushiming]

as i remmeber its not too hard and no i didnt replace them....i didnt replace it my self but i didnt watch carefully how it was done tho

 

[dcoghlan]

i replaced mine myself, and you have to remove the intake plenum so you get access to the injectors on the rail.

Use the right sized screwdriver as the screws holding the caps over the top of the injectors are tight, and you may make a mess of the head of the screw.

Also be careful pulling out the old injects... they will be held in extremely tighly, and don't loose the o-rings.

Be careful putting in your new injectors as you don't want to damage the pintles on them when putting them in.

As for the PFC, you can adjust this yourself to get the car running. I went from STD to 740cc injectors and changed the settings in the PFC myself so I could drive the car untill it went to get a full tune. It will run fairly rough and sound like its got big cams in it untill you get the PFC tuned to idle with the injectors properly.

 

[Nicely]

As Dale says, there is no need to remove the fuel rail. If you've done the job before, you can just undo the plenum, with nearly all pipes, etc still attached, and tilt it away to gain access to the injectors. The mentioned screws which hold the caps on are REALLY made of cheese. Its worth having a small set of moule grips if the screwdriver fails. I found the quickest and easiest way to remove injectors is using a standard pair of moules. Grip the injector JUST tight enough, twist and pull. Job done.

YOU MUST FIT NEW O RINGS!

As also mentoned, you need to pop the new injectors in cleanly. Apply a small finger covering of engine oil around the O rings to allow the injectors to pop in unhindered. Pinching an O ring when fitting an injector can cause fuel to piss everywhere under 3 bar of pressure...

 

[gunner93]

Well I have a shopping list (prob like everyone else)which includes a stroker kit so in essence I want to be up around 400hp mark. My PFC shows inj duty as upto a max of 93% at 1bar of boost so I assume 555's are not going to cope with my remap to 1.2bar (this is what I wanted initially) but Hyeline have let me down. Need to find someone with a rolling road to remap that are good at it too.

I also got the 740's cheap so it could not be passed, why is it overkill Gunner?

I've been maxing out my stock injectors as well under 1 bar of boost which is strange because many with similar setups dont max out like mine. :no:

 

[S15_Spec_R]

I've been maxing out my stock injectors as well under 1 bar of boost which is strange because many with similar setups dont max out like mine. :no:

Stock are 480's though arent they? After reading something on here about selectingthe right inj and that not to go above 80% duty. Might have read it wrong.

Thanks for the info guys I think I might leave it to the pros, anyone know of a good rolling road tuner as I dont think there is one in wales.

 

[gunner93]

Yes from the injector calculator guide, theoretically I should be using 600cc for stage 1 mod @ 1bar which will yield about 230-ish whp dynoed based our our local RON rating & climate humidity. Puzzling is, many S15 with similar stage 1 setup like mine dont max out on their 480cc injectors. These are folks whom have done spirited driving with speeds over 160mph. My hunch is probably pointing towards the quality of tuning.

 

[S15RKM]

i replaced mine myself, and you have to remove the intake plenum so you get access to the injectors on the rail.

Use the right sized screwdriver as the screws holding the caps over the top of the injectors are tight, and you may make a mess of the head of the screw.

Also be careful pulling out the old injects... they will be held in extremely tighly, and don't loose the o-rings.

Be careful putting in your new injectors as you don't want to damage the pintles on them when putting them in.

As for the PFC, you can adjust this yourself to get the car running. I went from STD to 740cc injectors and changed the settings in the PFC myself so I could drive the car untill it went to get a full tune. It will run fairly rough and sound like its got big cams in it untill you get the PFC tuned to idle with the injectors properly.

I did mine myself went to 555cc and the hardest part was getting the old ones out man they are tight,and be careful when installing new ones.

I really need to get a bit more familiar with my PFC I had my car tuned at RC Developments ( they are in Warrington if thats any good to you S15_Spec_R) but I now have a Z32AFM and looking for some 740cc's so will have to alter some settings in the PFC before I can get to the tuners again, dcoghlan/Nicely are there any web sites that run through the settings/setup of the PFC in English,I did find a couple but they weren't brilliant,any info would be much appreciated:thumbs:

 

[S15_Spec_R]

After looking at the plenum chamber I think I could replace the injectors. Is it just 4 (2 bolts and 2 nuts) nearest the strut? If so I could tilt it enough? Would new washers be a must if they are only 1k old? If not where would you purchase the washers from.

 

[Matt_S]

If you mean O rings. Err, me personally I dont like engine fires, so rather than run the risk of pissing fuel all over a nice hot engine I paid the £7 odd at Nissan for new ones (8 in all - 4 big, 4 small).
ANd theres more to it than just the four bolts n nuts you see. Its a bit of a ballache tbh and although I did mine myself, I was at APT and they offered me advice on the best way of not snapping bolts and what to do to get them out as easily as poss.

 

[gunner93]

Did a full on-road retune, advance ignition timing by 2 deg and lean out AFR up to half throttle. The knock is under 20 but water temp and injector is still the weak link at full boost. Look like bigger injectors, bigger radiator and Nismo thermostat in unavoidable now.