480cc injector flow-rate

[Nicely]

There has been a bit of dispute recently (not on this forum) over the actual flow-rate of 480cc injectors. Some people will just blindly say its 480cc @ 3 bar. Someone has said that its 440cc @ 3 bar (based on what it now obviously an error in the PFC manual). One thing was certain - no-one knew for sure and no cencrete info could be found. Until now.

I now have the flow-test results from two separate sets of 480s. Mine and another SXOC member's.

Mine returned 540cc @ 40 psi (approx. 585cc @ 3 bar)
The other set returned 528cc @ 40psi (approx. 570cc @ 3 bar)

3 bar is the standard pressure used for injector ratings.

Based on these results, it would actually have been closer to rate them as 555s... However, it is fairly safe to say that if your 480cc injectors are flowing 480cc, they are underperforming :nod:

 

[Hank S15]

wow, that is great info!

n00b mode on/ those are standard Spec-R injectors right? \n00b mode off.

Greetz,
Hank

 

[Nicely]

Yes, mate. Well, sort of...

JDM Spec R Manual = 480cc
JDM Spec R Auto = 370cc
JDM Spec S all models = 370cc
JDM Autech = 480cc

ADM Spec R and S = 480cc

 

[Meddy]

What duty cycle did they flow test the injectors at?

 

[Nicely]

I won't have the full report till Wednesday. At the moment I only know that they have tested at 60% (I think) and full flow. I'll post up the full details when I get them back.

 

[Meddy]

I won't have the full report till Wednesday. At the moment I only know that they have tested at 60% (I think) and full flow. I'll post up the full details when I get them back.

Ok its just that you would expect the flow at 100% to be higher than the 480cc as thats quoted at a 80 odd percent duty isnt it?

 

[Nicely]

The entire area seems to be a big mystery, so any info would be gratefully received.

 

[Meddy]

The entire area seems to be a big mystery, so any info would be gratefully received.

My understanding is that running injectors on or around 100% isnt a good idea. So manufacturers quote the flow figures at 80 odd percent 85-86 I think although I wouldnt take that as gospel. However obviously you can essentially obtain any flow figure you like by either upping the fuel pressure or changing the duty cycle when taking the measurements.

Also I dont think the measurement method is exactly amazing. They simply put the injector in a rig, set the duty cycle and the fuel pressure then dump the fuel into a measuring cylinder. After a minute on a stop watch/timer they stop the rig and read of a cc from the cyclinder, so with human error Id guess the figures provided are going to be plus or minus a good few percent.

 

[Nicely]

Well, if that's the case (and it seems quite plausible), they come in at about 490-500cc at 85%.

EDIT: after checking this, EVERY duty recommendation I've come across states not to exceed 80% of the maximum flow rate at 3 bar (43.5psi) when calculating injector sizing.

 

[Yakozan]

Very interesting find
Keep us updated on the actual flow. Would love to hear that they're 555s
That could mean Jez-chip safe

But I kinda doubt that we would be so lucky

 

[Nicely]

The info that I have now found (with Meddy's help) points to the flow rate being about right. This also clarifies the flow rate of some 555s someone else had tested too, as they seemed high as well. Jez reckons that they should be 444s going by the ECU. Apparently the Nismo catalogue has them listed as 444s too. However, the evidence shows they are closer to 480s.

 

[Nicely]

Got these back today. Full details are:

372cc @ 60% 6500rpm 7ms
540cc @ full flow

That's at 40psi. For 3 bar, that would be approx 404cc @ 60% and 587 @ full flow.

As mentioned 80% of the full flow figure @ 3 bar would be 470cc. Taking into account that the flow rate is better at 60% than 100%, I'd say that the ACTUAL 80% 3 bar flow rate would be around 480-500cc.

 

[Topper]

:thumbs: good work :nod:

 

[Yakozan]

Nice detective work there Nicely :thumbs:
now it's settled once and for all

 

[Nicely]

Except for the fact that the Nismo catalogue lists the standard S15 injectors as 444cc (I'm told) and, according to Jez, the ECU is setup for 444cc.

However, the result speaks for itself. I think its safe to say they are 480cc.

 

[Yakozan]

Well Apexi and Nismo could have got the info from the ECU?
why Nissan would make the ECU think they're 444's is a mystery. Hungover engineer??

 

[Nicely]

Well, absolutely PMSL! :rotfl:

Emailed Nissan Japan to ask what size injectors were fitted to the Spec R MT and what pressure they were tested at. Just got a reply back saying that the pressures were 2.5 bar at idle and 3 bar at full power. They couldn't tell me the size as they couldn't find it in their service manuals...

 

[Topper]

thats funny

 

[S15R]

they replied you in english?

 

[Topper]

I have called and e-mailed Nissan Japan and all times its been English :nod: