Injector Size Recommendations

[Slim Mat]

Hello,

Recently I have discovered that the standard RB26 injectors are leaking. The leak is coming from the injector casing so it can't be repaired and new seals will not fix it. This leaves me with the choice of getting some standard RB26 injectors (440cc) or upgrading now to higher flowing injectors for the future.

I don't know whether or not a standard GT-R ECU will be able to handle the differences though. So, what is the max size I could go to with aftermarket injectors that will still work with the ECU?

Cheers

<--- PS. How do I change the engine type under my avatar

Edited May 25, 2007 by Slim Mat

[Adriano]

Only way to upgrade injectors with the standard computer is to remap it

[Ryan1200]

My tuner once said he had a customer that ran 600's in his 33gtr on a standard ecu. They dyno'd it with the 600's and it was a little on the rich but thought it would be ok, 2weeks later the aftermarket computer arrived they checked the tune again with the standard ecu and it ran near perfect mixtures everywhere. In saying that it would be advisable to check the state of tune before going to silly with it. Ryan

Edited May 25, 2007 by Ryan1200

[Adriano]

The standard computer must have been remapped

[Slim Mat]

Adriano,

Why must I get the ECU remapped?

Cheers Ryan1200

[Birnie]

ANY ECU opens the injector at a certain percentage at a certain load point.

It doesn't care what injector is there it just does the % it's programmed to do at certain loads.

If the ECU works the 440cc injector at 40% at load X (approx 176cc/min)

It will still open a 740cc injector at 40% (approx 296cc/min) at the same load point unless you remap/reprogramm your ECU to tell it otherwise.

[Ryan1200]

Ok what i should have said is when they first installed the big injectors it ran rich, 2 weeks of driving the computer must have started pulling fuel due to the rich 02 feedback.

[Adriano]

O2 feedback is only a fuel trim, of 2 or 3%, and only works in certain load cells. It also doesn't self learn, as the computer wont lean out the whole fuel map, just every time it goes into closed loop, which is mainly in running temp, cruise conditions it will try to pull fuel out, but it cant trim anywhere near enough out to compensate for bigger injectors

[R31Nismoid]

A GTR reprogramming itslef? thats a new one

[Ryan1200]

Fullload afr's are ok slightly on the rich side. He said the cruise light load mixture was alot better than when it left maybe the 2 to 3 percent was enough. Or yes the car may have had a reprogamed chip i guess but it was strange he said the tune was rich then 2weeks later wasn't too bad.

Edited May 28, 2007 by Ryan1200

[Slim Mat]

Yeah, car ECU's can learn/reprogram fuel trims like Adriano was saying. I was hoping that that would be enough, with an ECU reset (deletes fuel trims and relearns all data), but, it seems that Adriano is saying that it won't be enough and will only work slightly at some times.

Thanks for a better explanation guys.

So has anyone got some GT-R injectors laying around? Don't need full set even.

<--- P.S Has anyone figured out how to change that bloody engine type under my pic?

[SLIPPERY]

dont you like rb20 shitta spec?

i think its under 'my controls' at the top of the page and have a look around in there

Edited May 30, 2007 by SLIPPERY

[Slim Mat]

dont you like rb20 shitta spec?

i think its under 'my controls' at the top of the page and have a look around in there

Hahaha, noooo to RB20

GT-R FTW!!!