Hi-flowing Injectors

[skylinecouple]

OK,heres something a little different.I have standard injectors that have been hi-flowed 20%.This should be 444cc.The rest of the setup is GCG hi-flow turbo,Justjap cooler,split dump,3" system,modded airbox,pfc,very low k R34 Gtt motor with all sensors changed to work in R33GTST.

The car is going in for final tune as it feels doughy between 2 and 3,000rpm.Oh,forgot to mention it has Profec B spec 11.

Now,guys,only the people who have really had some experience with these modified injectors,personally, or worked on a car using them.

Currently making 230rwkw.Are they a waist of time? I have heard so many bad reports yet just as many good ones.They certainly seem to have solved my fuel shortage problems.Though I wonder about spray patterns but AVO swear they are no different.Any comments?

[paulr33]

has it been tuned at all or just stock maps still?

have you had to dial in fuel injector adjustments under SETTING, INJECTOR to compensate for the larger flowing injectors, possibly with different latency, you could be dumping in far too much in the doughey spot you mentioned and its rich as all hell which would certainly give it that sucky feeling

[skylinecouple]

Was originally tuned by Croydon so don`t know what setup.Will be going to Unique Auto Sports monday and will find out current setup, then see new setup from Ben at Unique.Lots of soot and unburnt fuel over back of car.Never starts first time.

[paulr33]

sounds like its mega rich

[BHDave]

I've seen a set of sr injectors high flowed up to 690 or so and they seemed to do the job.

Like all aftermarket injector swaps it just needs the tune to be adjusted to match.

As paul has said, your car sounds like it is running stupid rich. An adjustment on the injector correction will get it close and then a touch up of the maps and you'll be fine.

[skylinecouple]

Thanks guys,I hope your right.Be prepared on tuesday and I`ll fill in details of set up.So easy to get distracted from the goal of getting the most result from the least combination.Most workshops now seem to be overly concerned with known setups rather than getting down to some fine tuning of an existing setup.In other words getting to know the PFC intimately.

[Fastrotor]

Hiflowing an injector is easy. Sure it flows the correct amount for its new size, but the trick is to make sure its atomizing correctly.

What happens if it isnt atomizing correctly is that the unatomized fuel wont burn properly and you end up having to open up you newly hiflowed injectors even more to obtain the correct afr your after. This obviously negates the effect of going bigger in the first place. And you find yourself back to square one running out of injector..... and scratching your head to boot.

I've personally seen an SR motor running 100% duty on some 550cc hiflow std injectors, and same motor with 550cc proper ones at 70%.....

On flow bench, both injectors flowed same amount...... but of course the hiflowed ones were atomizing badly.

Another thing is low speed accel pump tuning, it will make this difficult to get perfect if there not atomizing properly, as airspeed is very low.

Hope it helps.

Gary

[skylinecouple]

Well,got it back from tuner (unique auto sport).The difference is unbelievable.Ben did a great job.I must say it is very crisp and I know already that when I stop enjoying the new power it will return much better fuel economy.The thing is, how come the previous tuner made 230rwkw and Uniques dyno only made 217rwkw yet it is a much more powerful car.And I mean MUCH more powerful.There is no slowing down of the power.It keeps making more til redline.

Could there be that much difference between two dynos? By the way Fastrotor I actually agree with you on the atomisation but in this case I think AVO have done a great job.Oh, and it starts with no hesitation at all,thats the one thing that was really getting to me.I can`t say every body would be happy with hi-flows and I must admit I had thought I had waisted my money but now $450 beats $12-1400 or even $700 from greenline or nengun.I also heard injection perfection have cheap hiflowed injectors at $350on e-bay.

[Fastrotor]

Well,got it back from tuner (unique auto sport).The difference is unbelievable.Ben did a great job.I must say it is very crisp and I know already that when I stop enjoying the new power it will return much better fuel economy.The thing is, how come the previous tuner made 230rwkw and Uniques dyno only made 217rwkw yet it is a much more powerful car.And I mean MUCH more powerful.There is no slowing down of the power.It keeps making more til redline.

Could there be that much difference between two dynos? By the way Fastrotor I actually agree with you on the atomisation but in this case I think AVO have done a great job.Oh, and it starts with no hesitation at all,thats the one thing that was really getting to me.I can`t say every body would be happy with hi-flows and I must admit I had thought I had waisted my money but now $450 beats $12-1400 or even $700 from greenline or nengun.I also heard injection perfection have cheap hiflowed injectors at $350on e-bay.

Good to hear it all worked out well for you mate. Depends on what dyno Unique use, but there is always a difference even between same brands, sometimes its slight, sometimes large... depends on how often they get them calibrated. If your comparing between a Mainline Dynolog Dyno to a Dyno Dynamics type (most common) then yes, the dynolog reads about 15% lower. But as you've discovered, the proof of the pudding is in the eating.

Well theres no saying that there not atomizing properly, yours might be fine. Also, the ones im referring to were pretty good, it was only a very minor low speed accel pump prob that we noticed the prob in the real world........ other than that the dyno is where it showed the dramatic difference in duty cycle. Leading me to conclude they were not atomizing properly.

Gary

[paulr33]

please note a dyno is merely a tuning tool, tell us the max rwkw figure is kinda pointless

the average power, torque, afr, boost and power at each point is far more important.

far too many people only look at the max rwkw figure and decide wether its a quick car based on the max rwkw figure.

i would much rather a tune/car that makes good average power, has a safe afr curve and runs along 12's in the airfuel ratio and doesn't need a big stack of boost to make that average power, to me that car is much more quicker than a car that runs more boost, makes a much higher rwkw peak figure and has much more lag.

if it drives better then thats all that matters

[skylinecouple]

Good to hear it all worked out well for you mate. Depends on what dyno Unique use, but there is always a difference even between same brands, sometimes its slight, sometimes large... depends on how often they get them calibrated. If your comparing between a Mainline Dynolog Dyno to a Dyno Dynamics type (most common) then yes, the dynolog reads about 15% lower. But as you've discovered, the proof of the pudding is in the eating.

Well theres no saying that there not atomizing properly, yours might be fine. Also, the ones im referring to were pretty good, it was only a very minor low speed accel pump prob that we noticed the prob in the real world........ other than that the dyno is where it showed the dramatic difference in duty cycle. Leading me to conclude they were not atomizing properly.

Gary

Still, curiosity might get the better of me,I may still try the nizmo injectors just to see if any difference.By the way, just did full tank and got 400km driving mostly around town.Cold start is great and it now has a clean rear bumper.

[paulr33]

it should also be noted that on a correctly tuned and setup car (read; ECU) that fuel economy should not be affected by the injector size, nor should idle or cruising and so on. The ECU should be setup accordingly to deal with this, so that if you have 1000cc or 720cc or 370cc it runs the same and the ECU works it out accordingly.

Not insert 720cc nismo's injetors and you have crap idle and shit fuel economy this is not how it should be

[skylinecouple]

exactly Paul, I agree. If the factory can build fast cars that run cleanly then so can we. Bit of time and patience, thats all.