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Thanks for the info Jared, Ill be visiting a few local performance shops tomorrow and will approach them with the theory and see what they say. So far an injector expert has given me the thumbs up with the idea and said its been done before and has worked well... so a few more oppinions before i attempt this... otherwise its Nismo 555cc's

Cheers

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Ok guys, yesterday i visited a mates workshop and approached him the the "shaved injectors" idea and funny enough, he had just tried this on a customers car (S15 200sx) and this is what he found:

- Car was very hard to fine tune on top end - Haltech E11v2 (ran too rich)

- Poor Idle (rough)

He said that this mod will work better on N/A engines due to the compression... Once the S15 was fitted SARD 650cc's, the issues went away. The hypothesis was that the altered spray pattern caused poor atomisation and the different flow patterns made it harder to tune...

Cheers

Ok guys, yesterday i visited a mates workshop and approached him the the "shaved injectors" idea and funny enough, he had just tried this on a customers car (S15 200sx) and this is what he found:

- Car was very hard to fine tune on top end - Haltech E11v2 (ran too rich)

- Poor Idle (rough)

He said that this mod will work better on N/A engines due to the compression... Once the S15 was fitted SARD 650cc's, the issues went away. The hypothesis was that the altered spray pattern caused poor atomisation and the different flow patterns made it harder to tune...

Cheers

The main reason they probably have trouble that the top end is to do with the fact that there is no pressure after the injector valve once it is removed. The valve itself is not designed to have the full pressure drop across it. Having the plate there actually means there is still some pressure after the valve & also makes it easier for it to close off again.

Rough idle would have to be one of the most common complaints I had for injectors that were sent in & found to have poor spray patterns. Had many very happy customers after diagnosing that fault :).

Most pintle valve injectors close by moving out into the injector body when the solenoid is switched off so if anything fuel pressure and spring pressure are what shuts the valve . By fuel pressure I mean inside the injector body itself . Any restriction downstream of it would cause a pressure rise between the multi hole plate and the injector valve itself though this is unlikley to help it close .

If I was going to do this I'd experiment with the pink top Pulsar N15 GA16DE injector because shaved they are supposed to give somewhere in the mid 400's cc flow rate . When you start to get into 500 + cc injectors for 4-500 cc cylinders the computer has to be capable of controlling them at low engine speeds , it has to be able to open and close them very quickly and time the injector close stage accurately . The tuner has to have a good handle on the whole sequential injection process with aftermarket ECU's because there's a lot more to it than just spray it in and fire the spark plug , some of the Haltech people had little interest in sequential injection prefering batch fire which is a bit crude in this day and age . I know everyone says PFC's are good at accurate large injector control so they must have good injector drivers to do it well .

BTW the shaved injector was always going to be a cheap option and possibly the only one available for some people . Its very possible that the aftermarket has found ways to gut the injector and surface the seat area of the injector body and valve to help get better spray patterns , we need someone on the inside to tell the story here .

Cheers A .

Well from what i have found out, this mod does work however tuning will be harder as well as idle quality will suffer... im leaning toward a highflow set of 555cc from Deatschwerks or 550cc Nismo's...

cheers

Edited by QRI05E
  • 1 month later...

I know of a workshop in Melbourne that highflows RB25 injectors. They actually have the parts so when they shave them the refit new caps to give the right feed rate, then the flow test them so you can balance the injector pulses. They do charge about 70 each including the parts needed, clean and flow test so not a bad option there either.

Nice find though disco.

I know of a workshop in Melbourne that highflows RB25 injectors. They actually have the parts so when they shave them the refit new caps to give the right feed rate, then the flow test them so you can balance the injector pulses. They do charge about 70 each including the parts needed, clean and flow test so not a bad option there either.

Nice find though disco.

By any chance do you know what the workshop is called? I'm in the market for injectors at the moment...

yeah very interesting thread, my foreman told me about this as they've been doing it to WRX's for ages but they were using a CNC machine to open up the holes in the pintle cap. they said the hardest thing was getting the flow rates the same but using the CNC made it alot easier, but the price was and is about as much if not more than a new set of 555 etc. each to there own.

Do Creatd Motorsport offer cash back for your old injectors? :D

Deatschwerks offer:

R33 Injectors - ~$25USD each (~$190 AUD for a set of 6)

R32 Injectors - ~$12.50USD each (~$95 AUD for a set of 6)

Given that it brings the price down of the Deatschwerks injectors by a reasonable amount. (Down to the $300 bracket if I remember correctly)

Not that I know of. Rob just high flows the injectors you hand him. I guess the diff then is do you need 555cc or up to 700+cc. The prices then fall into line a bit better. Either way the prices are better than new retail so you can't go wrong.

  • 2 months later...
  • 1 year later...
ive just 'shaved' a set of known ka24de 270cc injectors, will rig up a test bench for these and pulse them to grab a pic of atomization.

then will be sent out to deatchworks to be cleaned and actual cc/min measured.

Ill be getting the rb25de injectors I have done this too tuned very shortly on a MT8 so I will post back with results.

I have some back up injectors there if it goes to shit but. See how bad the idle is.

Any updates?

i know this thread is old but im thinking its better off bumping this one then starting again.

I have a set of S15 injectors im selling, have been offered a set of high flowed injectors to swap, am i better off getting the S15 high flowed a little bit more (enlarging the holes if thats possible), getting the rb25 high flow items or just buying a set of 700cc injectors.

A lot of people from this thread should have had plenty of time to asess these, how many still have them and are happy with them?

  • 9 months later...

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