370cc injectors on a bolt-on only Maxima?

black_maxed95 · 06-10-2008, 08:45 AM

Hey guys, I need to replace my stock injectors so I figured I might as well upgrade now since in a year or so I plan on being boosted. However right now I am pretty much only bolted-on. Now I tried searching and it looks like I would need a aftermarket FPR also but I am at work and cant search too much right now. Most of the threads I read through were for people running boost so that doesnt help me now.

My question is can I run some 370cc 300zx injectors without other major changes besides a FPR? I dont have any tuning devices. I read that a 300zx MAF will help balance it out which I do have (not installed right now for obvious reasons tho).

What are the suggestions on this?

*NmexMAX* · 06-10-2008, 08:57 AM

Explain how you think a Z32 MAF will balance it out? If anything, that combo (Z32 MAF / injectors) will make you run richer than the injectors alone. You need a tuning device and a wideband. And, IMO, an AFPR is not a tuning device.

Why do you 'need' new injectors?

If anything I would wait it out until you went boosted, then toss in a new set of injectors relative to your boost level.

black_maxed95 · 06-10-2008, 09:08 AM

370cc injectors=more fuel
Z32 MAF=more air
Thats how...that is what I found searching, I didnt come up with that myself but it does make sense.

I realize a FPR is not a tuning device but it would be used to lower the fuel pressure so the injectors dont dump too much fuel in.

I admit I dont know much about this subject so that is why I am asking. But right now I have bad fuel injectors making my car run like crap and I figured I could upgrade now since I plan on going boosted soon. If its a bad idea over all I wont do it but that is why I am asking.

Im not 100% sure I 'need' new injectors but right now my car is hard starting and sputtering under hard acceleration. I have basically no power. I have gone through several other things to check and so far I have not found the problem. Fuel injectors were one of my next approaches.

**mtrai760** · 06-10-2008, 09:10 AM

I run 370cc injectors with a Z32 MAF and an adjustable fuel pressure regulator set to 34psi (stock FP). I have nothing else to control my A/F under stock (not boosting) conditions. When not boosting, my car drives normally, at 14.7 AFR. No starting or idling issues.

The big question that comes into play is how your car will act at over 50% throttle application, when your ECU goes to pure fuel maps and ignores AFR. I am boosted and have no issues, but I would think that you would run rich under those conditions.

I ran my 240sx with Z32 injectors and a stock MAF NA for a few months before I installed my turbo system, and did not have any running issues. The ECU's of the two are really not that different. I think you can get away with it, you just may run really rich under hard acceleration while NA. You will have to play around with it to be sure though.

black_maxed95 · 06-10-2008, 09:18 AM

Quote:

Originally Posted by mtrai760

I run 370cc injectors with a Z32 MAF and an adjustable fuel pressure regulator set to 34psi (stock FP). I have nothing else to control my A/F under stock (not boosting) conditions. When not boosting, my car drives normally, at 14.7 AFR. No starting or idling issues.

The big question that comes into play is how your car will act at over 50% throttle application, when your ECU goes to pure fuel maps and ignores AFR. I am boosted and have no issues, but I would think that you would run rich under those conditions.

I ran my 240sx with Z32 injectors and a stock MAF NA for a few months before I installed my turbo system, and did not have any running issues. The ECU's of the two are really not that different. I think you can get away with it, you just may run really rich under hard acceleration while NA. You will have to play around with it to be sure though.

Thanks, thats alot of what I wanted to hear. Soon I also plan on getting a wideband and a AFC also so that will help.

What FPR do you use?

*NmexMAX* · 06-10-2008, 09:24 AM

I was going by this:

Stock ECU, Z32 MAF, 550's...explained

black_maxed95 · 06-10-2008, 09:26 AM

Also I can only use 95-96 300zx injectors?
I look on ebay and I find alot that listed for 90-96. Im not finding much for the purple tops, most are dark red.

**nismology** · 06-10-2008, 09:48 AM

Quote:

Originally Posted by NmexMAX

Explain how you think a Z32 MAF will balance it out? If anything, that combo (Z32 MAF / injectors) will make you run richer than the injectors alone.

The Z32 MAF will lean things out regardless of which injectors are being run.

*NmexMAX* · 06-10-2008, 09:52 AM

Quote:

Originally Posted by nismology

The Z32 MAF will lean things out regardless of which injectors are being run.

By being slightly larger in ID,

**mtrai760** · 06-10-2008, 11:08 AM

Quote:

Originally Posted by black_maxed95

Thanks, thats alot of what I wanted to hear. Soon I also plan on getting a wideband and a AFC also so that will help.

What FPR do you use?

I use an AEM universal AFPR.

**Nealoc187** · 06-10-2008, 11:27 AM

I have 370s in my car temporarily since I'm using side feeds right now instead of top feeds with the 3.5. I have my base FP set at like 28psi I think (never adjusted it. car fired up on the first crank after the swap so I never bothered to mess with it) - z32 maf and emanage blue. a good amount of tuning on EB was required to get the AFRs where they should be. pulling fuel in the very low rpm/idle range and adding fuel most everywhere else.

black_maxed95 · 06-10-2008, 11:34 AM

Quote:

Originally Posted by mtrai760

I use an AEM universal AFPR.

Does that have a guage built on to it? I was looking on ebay and it didnt look like they did. The OBX universal ones looked nice and had gauges. They were cheaper too but obviously OBX isnt going to be as good of quality as AEM.

Quote:

Originally Posted by Nealoc187

I have 370s in my car temporarily since I'm using side feeds right now instead of top feeds with the 3.5. I have my base FP set at like 28psi I think (never adjusted it. car fired up on the first crank after the swap so I never bothered to mess with it) - z32 maf and emanage blue. a good amount of tuning on EB was required to get the AFRs where they should be. pulling fuel in the very low rpm/idle range and adding fuel most everywhere else.

thanks for the info, I should probably get a wideband and AFC also.

**mtrai760** · 06-10-2008, 11:41 AM

Quote:

Originally Posted by black_maxed95

Does that have a guage built on to it? I was looking on ebay and it didnt look like they did. The OBX universal ones looked nice and had gauges. They were cheaper too but obviously OBX isnt going to be as good of quality as AEM.

thanks for the info, I should probably get a wideband and AFC also.

No, I purchased a 0-100psi gauge from Jegs, and I have a electric fuel pressure gauge in the car. I trust AEM a lot more than OBX, but there are good FPR out there that are cheaper than the AEM.

*mowgli29* · 06-10-2008, 12:21 PM

Quote:

Originally Posted by mtrai760

I use an AEM universal AFPR.

sorry this is a little OT...how much did you pay for it?
Are the $50 ebay AFPR's crap?

95BLKMAX · 06-10-2008, 12:42 PM

Quote:

Originally Posted by black_maxed95

[....] should probably get a wideband and AFC also.

SHOULD? more like you NEED to get those things PRIOR to installing the 370s so the car will run right.

But with that working all together, you'll be just fine

**mtrai760** · 06-10-2008, 01:28 PM

Quote:

Originally Posted by mowgli29

sorry this is a little OT...how much did you pay for it?
Are the $50 ebay AFPR's crap?

I paid around $150 for mine a year ago. Keep in mind that you will also need to purchase fittings for it, which can get expensive.

I have no experience with the ebay ones, I know some people use them with no issues.

*t6378tp* · 06-10-2008, 01:47 PM

Stay away from cheap afpr, I had a name brand afpr and had problems with the diaphram blowing out. And trust me you do not your afpr going bad.

*NmexMAX* · 06-10-2008, 02:03 PM

Nismo unit is ~ 120$ from Courtesy.

95BLKMAX · 06-10-2008, 02:12 PM

Quote:

Originally Posted by mtrai760

I paid around $150 for mine a year ago. Keep in mind that you will also need to purchase fittings for it, which can get expensive.

I have no experience with the ebay ones, I know some people use them with no issues.

Indeed. I bought a greddy knock-off on ebay for $55 when I first did the swap. The sucker didnt last more than 3 months before it got stuck internally and whored the pressure to 75psi and would not adjust down from there.

I then called Justin from ImportCarPartsPro and I got a Fuelab AFPR for $139shipped.... it was expensive for SO worth it. Super dupper high quality piece.

locknuts · 06-10-2008, 07:27 PM

Quote:

Originally Posted by t6378tp

Stay away from cheap afpr, I had a name brand afpr and had problems with the diaphram blowing out. And trust me you do not your afpr going bad.

+1 defently buy a qualilty peice. i got a knock off one off ebay. and i hooked it up for about a week and before i knew it i had gas spewing out the vaccum