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Sr Injectors Max Out@6,5k Rpm!

West

By West,
in Engines & Forced Induction

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West Grand Master

West

Posted
Posted

Good day all,

my mate has a Red Top SR20DET, offcourse with all the usual mods + PFC but for some reasons the injectors max out at only 9psi and hit 100% duty cycle already.

I forgot to mention its a 92model 180sx RED TOP. Meanwhile my other friend has a 95 model 200zx and making 187kw@wheels ( black top ) and runing 16psi and injectors only max out then.

i believe both engine has the same injectors rating, why one run 100% at only 9psi and other can reach up to 16psi?

can your injectors be so dirty, old to cause such consequensive or its the fuel pump?

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nfi Community Regular

nfi

Posted
Posted

One is tuned leaner than the other.

I am guessing that the pfc on the (redtop) car is running way to rich. Get the redtop car tuned properly and that won't happen.

Do you have a dyno sheet of the redtop car tuned? If you do, make sure the afrs are above 11.5 but under 12.0 roughly for a reliable street car.

Thunderbolt Rising Star

Thunderbolt

Posted
Posted

I had the exact same problem with my redtop. Was maxxing out not only the injectors, but also the AFM at around 150rwkw. This wasn't so noticable in day-to-day driving, but at the strip it was causing me to back the boost right off. Have since changed to Z32 afm and 740cc injectors and have not looked back since.

West Grand Master

West

Posted
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Posted
I had the exact same problem with my redtop. Was maxxing out not only the injectors, but also the AFM at around 150rwkw. This wasn't so noticable in day-to-day driving, but at the strip it was causing me to back the boost right off. Have since changed to Z32 afm and 740cc injectors and have not looked back since.

I see, i thought injectors duty is somewhat we can input signals in and make them to work either 80% or 90% at certain points.

nfi Community Regular

nfi

Posted
Posted
I see, i thought injectors duty is somewhat we can input signals in and make them to work either 80% or 90% at certain points.

You can but its not quite as simple as that. You basically have two tables and a correction map for air density vs timing. One is for ignition timing and the other is for injector timing. With too much timing the car will have to run excessively rich not to ping and that is what I am guessing is happening to you.

Putting bigger injectors with the power you have is a band aid. The car will run WAY better getting in tuned with your existing injectors rather than buying bigger ones. Not only will it make more power being tuned with the existing injectors but it will also be much nicer to drive in terms of throttle response and the linear nature of the power delivery as well as using much less petrol.

Seriously get it tuned asap... You won't regret it ;) With the stock turbo your car should make around the 160-175rwkw mark. But all dynos will show slightly different figures. They are just tuning tools.

If your in sydney PM me and I will suggest a place to go who will do a good job. A proper tune is also cheaper than injectors as well!

Thunderbolt Rising Star

Thunderbolt

Posted
Posted

Mine was tuned, but was still maxxing out (may have been the AFM reading well over 5000mv but yeah). Drivability is very nearly as good with my 740cc injectors and z32 afm, so I wouldn't worry too much if you decide to go bigger injectors.

Can't see how bigger injectors is a band-aid solution (considering you would get it tuned anyway). Band-aid solutions come when you adjust the fuel pressure to get more out the injectors.

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