Difference Between High Flow Injectors

[Pal]

hey all,

had a set of high flowed sr20 injectors (flowed to 600cc) fitted to my car a few weeks back. since then i've noticed black carbon on my rear bar and chewing the fuel. i haven't been doing alot of boosting but am still getting just under 15l/100. to me this is too much so thinking its maybe to O2 sensor (was replaced about 1 year ago). got in contact with my tuner who is adamant that its the high flow injectors are causing the problem (bad spray pattern due to being drilled) not the tune. i got a power fc and high flow turbo.

[STATUS]

hey all,

had a set of high flowed sr20 injectors (flowed to 600cc) fitted to my car a few weeks back. since then i've noticed black carbon on my rear bar and chewing the fuel. i haven't been doing alot of boosting but am still getting just under 15l/100. to me this is too much so thinking its maybe to O2 sensor (was replaced about 1 year ago). got in contact with my tuner who is adamant that its the high flow injectors are causing the problem (bad spray pattern due to being drilled) not the tune. i got a power fc and high flow turbo.

we have no dramas using high flow injectors providing they are done properly. Get an independent dyno check.

[Pal]

was thinking off this but wanted any other ideas of all the experts out there

[R31Nismoid]

could be a failing fuel reg - checked pressures?

[Pal]

brand new nismo FPR

[R31Nismoid]

What i said stands - re: fuel pressures. Perhaps the FPR was not set correctly.

[Pal]

i know its still slightly over standard rail pressure from when i had the stock injectors in (about 2 psi over). is this what you mean or to pressure to low?

[PM-R33]

I'm a bit curious on this. Lately i swear my car is using more and more fuel. $30 of BP Ultimate gets me about 100-150km's driving to and from work, im pretty sure it used to get me around a lot more.

I was thinking maybe the oxygen sensor is f**ked from using antilag every now and then, however i'm not sure whether Microtech's and other non Power FC ECU's use the standard oxygen sensor.....?

Edited July 14, 2009 by PM-R33

[Fastrotor]

My moneys on the injectors. Getting them to flow a certain rate is easy.... getting them to atomise like std ones once modded is the problem. You can get a certain afr your aiming for, but theres alot more fuel going in than required , as the unatomised stuff goes straight out the pipes.

Case in point, bout 5 years ago i wired and dyno'd an SR20 for a mate, against my advice he got the stocker's flowed to 550cc ... and said the guy promised they atomized perfectly...... Anyway i maxxed them out, 100% ..... ok, car still ran fine, except once small transition area off boost, i could not get rid of a small hiccup, no matter what i tried.... anyway left it there.

Month later i did another SR20 but this time guy used some factory 550cc injectors, made the same power, same fuel pressure (i always fit a gauge). ....... however............ only using 70% duty cycle. I was expecting a difference but not that much ! It opened my eyes quite abit.

Gary

[PM-R33]

Gary do you know much about the Microtechs and O2 sensors? I know the older models couldnt run them in closed loop, but i read somewhere the LT12S does. I hooked the laptop up and had a flick around to check if it was running in closed loop but i cant seem to find a setting anywhere. I'm pretty sure my O2 would be rooted (i've never replaced it since owning the car) however i dont know whether to replace it or not considering the Microtech might not even use it. You know anything about this? I might go ask Pete when i get a chance.

[Pal]

Thanks for the info Gary, might be a matter off starting to save for some proper injectors and get rid of these

[Sydneykid]

My moneys on the injectors. Getting them to flow a certain rate is easy.... getting them to atomise like std ones once modded is the problem. You can get a certain afr your aiming for, but theres alot more fuel going in than required , as the unatomised stuff goes straight out the pipes.

I've seen that on an N/A engine, especially with individual lambda sensors in the primary pipes, but never on a turbo engine, with a single sensor after the turbine . My theory has been that the hot exhaust turbine spins up the unatomised fuel, so it becomes atomised and hence shows up as richness on the F&W lambda sensor. Maybe I've just been lucky.

Pretty soon we will all be running on E85 and then it won't matter what the injector spray pattern is like, ethanol has such superior atomisation.

Cheers

Gary

[bozodos]

PM_R33 my LT10S has the O2 sensor physically disconnected, and yeah I get about the same fuel economy as what you're getting effing shite ECU's they are, can't wait to get rid of it.

back on topic, is there any advantage to say getting standard RB25 injectors high flowed, or would it be better to get say S15 ones?

[PM-R33]

I don't mind the Microtech at all. Maybe mine is still tuned a lot richer than what a lot of you guys run, i dunno. I'm going to find out if it uses the 02 sensor, could have something to do with it. That fuel has to be going somewhere...

[EFI Performance]

I would be looking toward the tune in the ECU, remembering microtech's have poor timing control for light throttle cruising, there injector control is also poor.

The injector spray does play a part in this also, and I will honestly say this

WHO THE f**k HIGH FLOWS INJECTORS.

Do not use them and do not sell them.

My 2c

[PM-R33]

Well let's just all jump on the "Payout Phil's ECU Train" lol. Yeah i know they aren't the best ECU. But when i put my foot down my boost gauge needle fly's really fast and car's in the mirror get really small...... I still smile

Edited July 16, 2009 by PM-R33