510cc JDM injectors underrated?

[Sotarts]

I have yellow-top 510cc injectors from Evo III.

I keep hearing that JDM 510's from Evo III are underrated. Is that true?
How much are they underrated?

I'm currently tuning with GM MAFt and have set the injector size to 510 (and the car idles like garbage, and dies right away...). Should I set it to bigger injector size, how much bigger?

 

[psychlow]

I'd try 550's, if I was pretty sure the car was running rich.

 

[Sotarts]

I'd try 550's, if I was pretty sure the car was running rich.

Excuse me?

 

[psychlow]

Excuse me?

If you're sure that the car is running rich (black smoke in the exhaust, possibly wet spark plugs, etc) then bump up the injector size setting on the MAFT to 550.

 

[Sotarts]

If you're sure that the car is running rich (black smoke in the exhaust, possibly wet spark plugs, etc) then bump up the injector size setting on the MAFT to 550.

Isn't that a little extreme? Seriously now.

I have no catalytic converter, so black smoke a lot of times is inevitable. And "wet spark plugs" is just irrelevant... Black spark plugs would make more sense.

 

[kpt4321]

Use a damned logger to tune, don't bother guessing at what will work best based on the smell and color of the exhaust.

A test pipe doesn't make black some any more likely.

 

[psychlow]

And "wet spark plugs" is just irrelevant... Black spark plugs would make more sense.

I definitely agree with the logger suggestion. Only way to tune.

Indeed, if it's not dumping enough fuel to make them wet, it'll probably just leave a lot of soot, so yes. I was being lazy and didn't bother typing out everything. Point is, you know how to read sparkplugs and check. When I run rich at idle, I usually have fuel moisture on the plugs.

And no, I don't think an ~7.85% increase would be unreasonable.

 

[Sotarts]

Is there anyone that actually has info or data relevant to JDM 510's?

 

[midnght]

I can not find the site I have seen this on, but...

A guy got his tested at 536cc's.



Hope that helped.

 

[Sotarts]

I can not find the site I have seen this on, but...

A guy got his tested at 536cc's.



Hope that helped.

That helps 1,000,000% more than anyone else in this thread. Thanks!

Anyone else have relevant info?