Im going to pull my plenum soon to replace hoses, upgrade injectors to 555's etc. I heard that the old style injectors(90-94) are more prone to failure than the new style. So to convert to the new style I would need to get a 94+ lower plenum or have my current one machined and solder the new connectors to the harness right? I don't want to spend all the money on the 90-94 style upgrade and have one or two of them go out after 10k miles or so. Anyone have any problems on their 90-94 with just upgrading injectors? I have heard of some not even lasting 3k miles!

 

Are you referring to the stock injectors prone to failure depending on style? Or that the new Nismo 555 cc injectors that are made in the old style are prone to failure?
Seems to me that if the injector is bad to begin with, it'll go bad regardless. That's why they should be tested before installation. Maybe many ppl are assuming that because they're new that they'll work fine outta the box. Injectors are relatively easy to check with a mulitmeter.
I could see maybe a few isolated instances where a bad injector got to market. I haven't heard of brand new injector failure though.
Don't forget though, just installing larger injectors won't give you more power. The ECU needs to be programmed for them.

 

Can you leave the ecu alone and add a SAFC to tune with the new injectors?

 

Why not go with the PE 850cc kit sold by Z1? It comes with the fuel rails and the lower intake manifold. It's not that much more than buying the 555cc NISMO injectors separately.

 

Yes I know my eprom will need to be reburned. I have been reading about some people having problems with the old style Nismo upgrade injectors after a few thousand miles. Maybe they just got a bad batch of injectors, who knows. I heard that the newer style was more reliable and wanted to hear what you guys thought about it. I mean my stock injectors are fine for the time being but I will probably upgrade to bigger turbos later on down the road and need the added fuel delivery. 91zxtt, do you know anyone with the kit and are they having any problems?

 

No, I haven't heard anything about those. Z1 hasn't been selling them for all that long. I plan on going with those, when the time comes.