"shaved Injectors" ?

[discopotato03]

Personally i run rx7 ser V squirters which are thought to be bad in the spray pattern dept., but im getting similar fuel economy to Cubes (10L/100km) with his GTR injectors.

People here with r33's are getting the same economy (if not worse) with their supposed better quad squirters.

Everyone tunes for the 12:1, so if we all get the same fuel economy and AFR's then i say go for it, as spray pattern wont mean much to the final product -UNLESS its a big dribbler

I'm still waiting for feedback from the States about a fellow using Nissan SF 270cc injectors shaved to 550cc in a V6 Probe Turbo . He did this a year or so ago (pre turbo conversion) and with a "basic" piggyback (I think) called Mega Squirt , said he got factory idle - std injectors were ~ 220cc .

Our big issue is cost , everyone would use Nismo 555's or even the Red S15 injectors except for the $900 or $450 + price . Even if fuel consumption suffered by some small amount to use up the difference in fuel cost would take some time . Fingers crossed the PFC is as good as everyone says it is .

When I can find one I intend to de cap a pink top GA16DE injector which I believe are side feed and have it tested alongside an R33 GTR injector , in theory this makes for two single pintle valve injectors of around 440cc . Provided the spray pattern is similar/same then that makes an easy upgrade for my R33 and cheaper than S15's . If it then runs out of fuel well I suppose decapped 270's at 550 odd should be ok .

As I mentioned before I previously used Bosch 403 injectors which are a single valve 503 cc injector and when clean really moved some fuel on the test bench , probably very similar to the RX7 ones . Ages ago I asked SK about RX7 injectors as an RB26 upgrade and he had no problem with them . He said the issue was getting enough fuel in at the boost threshold phase .

Till then have to wait and see .

Cheers A .

Cheers A .

[QRI05E]

Just spoke to a fuel injection expert and he said this mod is "certainly feasible" just need a rising rate fuel pressure reg + decent tune and should be all sweet. He commented that he has seen it done on WRX's with no drama's... Power Flow Injections in wetherill park told me that a "high flow" of an injectors is simply increasing the pintle size on the cap and ballancing the hole sizes... internally nothing is touched!

Keep us posted on the results guys!

Regards,

Sarkis

[discopotato03]

Yes I'm sure those in the know would rather keep it under wraps . So highly likely people have been paying big money for very little difference over standard fare . You gotta love market forces .

Cheers A .

[discopotato03]

Spray pattern reported to be good .

[sinistaGTR]

when we get this all confirmed can we make a sticky or new thread with what exactly is done how much and results etc just so ppl dont have to read through pages and pages this is turning out really well with these injectors

[WogsRus]

Yeah i am about to talk to a mate that does nothing but fuel injectors and see what is said. Will post back soon.

[QRI05E]

*Sarkis cracks his knuckles and gets his trusty metal saw ready*

[WogsRus]

Hay guys, Talked to my mate at Automotive service solution in Tas, they do all the fuel injectors here, use to be petrojet.

Anyway, he said that it has been done for ages, and it does work. only thing is that they can not ballance the injectors properly to flow thesame if they are out, as the pintle can't be changed. Other then that he has seen people using these for ages, and with no ill effects, other then some crappy fuel ecconomy of not tuned properly. SO there you go.

THIS DOES WORK.

Now he did not state officialy on the record that he recomends this being done, but i did get a wink to say it was ok.

[raz0r$harP.UK]

so it sounds like the go would be to mod the injectors then get them flow tested to see if there is any major difference between individual injectors...

how much does flow testing cost approx?

[aphid]

great thread, wondering though if it would be possible rather than removing the front cap to just increase the size of the 4 holes in the front of it, thus keeping the 4 jets as opposed to the large 1 jet, as this could only help improve the atomisation of the fuel?

[J_Red33]

Ok guys well this has been a bit of an interesting read for me. I am personally quite experienced in fuel injector testing & have seen some of this stuff done on several occasions, but seldom have seen it done good enough. So first I'd like to respond to a few comments made.

So let me get this right, if i remove the 4 hole caps off the top of the RB25DET injectors they would they would be at ~550cc flow?

If this is so then im WRAPPED lol but how come none of the tuners have ever discovered this? would the single pintle flow cause any disruption to economy? or cause unburnt fuel?

Cheers

This is highly probable, especially if the fuel comes out as a solid jet. For fuel to atomise properly it means it has to start mixing well with the air the moment it leaves the injector.

people do know, iv heared of people doing this to wrx injectors for at least a year if not more.

on the test bench the one i done just squirted out one large jet rather then four from the factory 4 hole plate, i dont know what this would do for atomisation etc, but at the end of the day its still only 4 jets not some special mist.

How much pressure were you running when testing the injector?

If all you got when testing the injector with the end plate still on was a solid jet, then the pressure simply wasn't high enough to test it properly.

I flowed a shaved injector today, the spray pattern was just one fine jet, when compared to a stock injector it just had 4 jets, looked exactly the same just four rather then one.

I dont know what a good flow is suposed to look like, but its was just one big jet rather then 4 smaller ones.

^^^^ as per my last comments.

Personally i run rx7 ser V squirters which are thought to be bad in the spray pattern dept., but im getting similar fuel economy to Cubes (10L/100km) with his GTR injectors.

People here with r33's are getting the same economy (if not worse) with their supposed better quad squirters.

Everyone tunes for the 12:1, so if we all get the same fuel economy and AFR's then i say go for it, as spray pattern wont mean much to the final product -UNLESS its a big dribbler

The quality of the R32 GT-R injectors to the RX-7 injectors isn't that great as they use basically the same generation injection technology, however the 32 injectors are prone to body leaks..... good for engine fires.

R33 injectors (& these side feed injectors in general) on the other hand give fantastic spray patterns & are generally very reliable too. The newest type Bosch injectors also use a very similar set up only top feed (JECS is actually owned by Bosch) & these are also very good injectors.

There are several reasons for not getting good fuel economy with O2 sensors also being a very common problem & too often an overlooked reason that's relatively cheap & very easy to fix.

Hay guys, Talked to my mate at Automotive service solution in Tas, they do all the fuel injectors here, use to be petrojet.

Anyway, he said that it has been done for ages, and it does work. only thing is that they can not ballance the injectors properly to flow thesame if they are out, as the pintle can't be changed. Other then that he has seen people using these for ages, and with no ill effects, other then some crappy fuel ecconomy of not tuned properly. SO there you go.

THIS DOES WORK.

Now he did not state officialy on the record that he recomends this being done, but i did get a wink to say it was ok.

Yeah it's ok as far as making the bigger holes is concerned, but it has to be done very precisely for it to work as well as it should. The holes all need to be drilled cleanly with pin point accuracy to ensure the spray pattern is not too narrow or broad. The further out from the middle the holes are, the greater the angle of each individual stream from dead straight. If chopping off the plate means that you only get a solid jet of fuel, there is no way in hell that this is going to work as well as a deacent set of aftermarket injectors.

Inconsistencies in the hole sizes will also result in greater variation in flow too. There was 1 comment I read that said the variation in flow was only about 5cc/min on a set flowing over 500cc/min each. This is VERY good if not execptional work (better than standard in many cases), so excuse me if I'm just a little juvious about the results they gave. Ones I have tested in the past have had much greater variations than this & none have sprayed as well as good quality aftermarket injectors.

Another point to make is that fuel injectors, while most of the time they are tested just flat out on all the time NEVER operate that way. Fuel injectors are switched on & off with each engine cycle to give the precise amount of fuel required at exactly the right time. Opening & closing an injector is not instantaneious & does in fact take a very short time to open & close.

While some sets of injectors will all flow the same flat out, they may not do so when they are being pulsed on & off continuously just as they would in an engine. Doing this kind of testing I have sometimes seen quite big variations that would otherwise not have been noticeable if they were just flowed flat out (This is also where RX-7 injectors fall down the most). Spray patterns can also be seriously messed up when doing this & I have failed dozens of injectors for this reason (much more common on injectors with an exposed pintle), which in some cases was the only problem that they ever had.

I short this kind of stuff is do-able & I'm not going to say it can't/shouldn't be done, but there are numerous possibilities for things to be wrong so tread carefully, don't get greedy & don't expect them to be AS good as as factory made high-flows or you may be dissapointed. Personally I'd spend the extra money on a set designed to flow at the higher level in the first place.

I hope people find this information usefull

Edited January 3, 2007 by JazzaR33

[WogsRus]

flow testing is $25 per injectorm that includes a service and clean, or $10 for flow test.

The holes are impinging flow to allow for better flow. BUT i presume one could just grind the top nice and flat to look profetional.

[WogsRus]

thats some great info there JazzaR33. I think it would be good if somone could do some accurate test.

[J_Red33]

I'd do it myself if I had the equipment, but I no longer do this for a living. Learning about all these little details when I could was the only thing that stopped me going insane!!

[4door_Sleeper]

I'd do it myself if I had the equipment, but I no longer do this for a living. Learning about all these little details when I could was the only thing that stopped me going insane!!

Would one solution to some of the problems you outlined be to do this to numerous sets simultaniously and put matched sets together.

Given that they might not work as well as aftermarket sets (yet plenty of Holly carbs spray 1 big jet and have poor atomisation), most people wouldnt need all 550cc from the injector, and inconsistencies would be compensated for on the dyno (assuming anyone considering this has at least got programable fuel if not a full ecu).

If someone were to linish and test several sets at once a jig could be set up to make this easier, and all injectors tested on a home made fuel rail/pump/regulator with callibrated containers under each injector.

I'm sure most people on here would pay a small premium for this to be done, and its not beyond the abilities of someone with a good shed/workshop.

Edited January 3, 2007 by 4door_Sleeper

[QRI05E]

From everyone i have spoken to, tuning is going to be the biggest let down. Due to each injector having a slightly different flow as well as not being able to ballance them, tuning each injector will be harder as well as less accurate. I might try this and see how it goes and worst case ill get a set of nismo's.

If anyone gets a chance to flow test and dyno tune this settup, please post your results.

Regards,

Sarkis

[Bl4cK32]

that would be one of the advantages of doing batch highflows, as you could match a set that flows all roughly the same.

[QRI05E]

Yea but i have been told that once the 4 hole cap has been removed off the injector, the single pintle (jet) cannot be ballanced... If any of you can get a set flow tested with the cap removed and post the results, it may save alot of people few $$$ that can be spent on other mods.

Cheers

[666DAN]

Bah!!!! Damn R34's and their shitty, uncommon top-feed jobbies!

[J_Red33]

Would one solution to some of the problems you outlined be to do this to numerous sets simultaniously and put matched sets together.

Given that they might not work as well as aftermarket sets (yet plenty of Holly carbs spray 1 big jet and have poor atomisation), most people wouldnt need all 550cc from the injector, and inconsistencies would be compensated for on the dyno (assuming anyone considering this has at least got programable fuel if not a full ecu).

If someone were to linish and test several sets at once a jig could be set up to make this easier, and all injectors tested on a home made fuel rail/pump/regulator with callibrated containers under each injector.

I'm sure most people on here would pay a small premium for this to be done, and its not beyond the abilities of someone with a good shed/workshop.

Yes it is possible that testing would help as far as the flow rates are concerned, & if you're very lucky matching spray patterns too.

Still you probably won't get them as closely matched as a brand new set & you will end up spending more money when it comes to tuning.

Yeah the most expensive part would be the flow tester. The best flow testers are actually a flow tube with a needle as you can see any inconsistencies with individual pulses of fuel. A bit of electronics to run the set up is also required for running the injector. Making up the rest is then a piece of cake.

Yea but i have been told that once the 4 hole cap has been removed off the injector, the single pintle (jet) cannot be ballanced... If any of you can get a set flow tested with the cap removed and post the results, it may save alot of people few $$$ that can be spent on other mods.

Cheers

Yeah dead right, you can't do anything once that top is removed unless you've got the skills of a master fitter & turned (plus very bloody expensive tools) & can attach a new plate.

What it flows once that plate is gone is what you're stuck with.

Edited January 4, 2007 by JazzaR33