Jump to content
SAU Community

Recommended Posts

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.

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.

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 by PM-R33

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

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.

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

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?

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...

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

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 :iluvff:

Edited by PM-R33

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Thanks, I removed the fuse and the relay from the car and made my own circuit with them to test them with a test bulb.  I will look for the wiring diagram and go from there.
    • Jdm DC2R is also nice for a FF car compared to the regular hatches of the time.
    • Now that the break-in period for both clutch and transmission is nearly over I'd like to give some tips before I forget about everything that happened, also for anyone searching up how to do this job in the future: You will need at least 6 ton jack stands at full extension. I would go as far as to say maybe consider 12 ton jack stands because the height of the transmission + the Harbor Freight hydraulic platform-style transmission jack was enough that it was an absolute PITA getting the transmission out from under the car and back in. The top edge of the bellhousing wants to contact the subframe and oil pan and if you're doing this on the floor forget about trying to lift this transmission off the ground and onto a transmission jack from under the car. Also do not try to use a scissor jack transmission lift. You have to rotate the damn thing in-place on the transmission jack which is hard enough with an adjustable platform and a transmission cradle that will mostly keep the transmission from rolling off the jack but on a scissor lift with a tiny non-adjustable platform? Forget it. Use penetrating oil on the driveshaft bolts. I highly recommend getting a thin 6 point combination (box end + open end) wrench for both the rear driveshaft and front driveshaft and a wrench extension. These bolts are on tight with very little space to work with and those two things together made a massive difference. Even a high torque impact wrench is just the wrong tool for the job here and didn't do what I needed it to do. If your starter bolts aren't seized in place for whatever reason you can in fact snake in a 3/8 inch ratchet + 6 point standard chrome socket up in there and "just" remove the bolts for the starter. Or at least I could. It is entirely by feel, you can barely fit it in, you can barely turn the stupid ratchet, but it is possible. Pull the front pipe/downpipe before you attempt to remove the transmission. In theory you don't have to, in practice just do it.  When pulling the transmission on the way out you don't have to undo all the bolts holding the rear driveshaft to the chassis like the center support bearing and the rear tunnel reinforcement bar but putting the transmission back in I highly recommend doing this because it will let you raise the transmission without constantly dealing with the driveshaft interfering in one way or another. I undid the bottom of the engine mount but I honestly don't know that it helped anything. If you do this make sure you put a towel on the back of the valve cover to keep the engine from smashing all the pipes on the firewall. Once the transmission has been pulled back far enough to clear the dowels you need to twist it in place clockwise if you're sitting behind the transmission. This will rotate the starter down towards the ground. The starter bump seems like it might clear if you twist the transmission the other way but it definitely won't. I have scraped the shit out of my transmission tunnel trying so learn from my mistake. You will need a center punch and an appropriate size drill bit and screw to pull the rear main seal. Then use vice grips and preferably a slide hammer attachment for those vice grips to yank the seal out. Do not let the drill or screw contact any part of the crank and clean the engine carefully after removing the seal to avoid getting metal fragments into the engine. I used a Slide Hammer and Bearing Puller Set, 5 Piece from Harbor Freight to pull the old pilot bearing. The "wet paper towel" trick sucked and just got dirty clutch water everywhere. Buy the tool or borrow it from a friend and save yourself the pain. It comes right out. Mine was very worn compared to the new one and it was starting to show cracks. Soak it in engine oil for a day in case yours has lost all of the oil to the plastic bag it comes in. You may be tempted to get the Nismo aftermarket pilot bearing but local mechanics have told me that they fail prematurely and if they do fail they do far more damage than a failed OEM pilot bushing. I mentioned this before but the Super Coppermix Twin clutch friction disks are in fact directional. The subtle coning of the fingers in both cases should be facing towards the center of the hub. So the coning on the rearmost disk closest to the pressure plate should go towards the engine, and the one closest to the flywheel should be flipped the other way. Otherwise when you torque down the pressure plate it will be warped and if you attempt to drive it like this it will make a very nasty grinding noise. Also, there is in fact an orientation to the washers for the pressure plate if you don't want to damage the anodizing. Rounded side of the washer faces the pressure plate. The flat side faces the bolt head. Pulling the transmission from the transfer case you need to be extremely careful with the shift cover plate. This part is discontinued. Try your best to avoid damaging the mating surfaces or breaking the pry points. I used a dead blow rubber hammer after removing the bolts to smack it sideways to slide it off the RTV the previous mechanic applied. I recommend using gasket dressing on the OEM paper gasket to try and keep the ATF from leaking out of that surface which seems to be a perpetual problem. Undoing the shifter rod end is an absolute PITA. Get a set of roll pin punches. Those are mandatory for this. Also I strongly, strongly recommend getting a palm nailer that will fit your roll pin punch. Also, put a clean (emphasis on clean) towel wrapped around the back end of the roll pin to keep it from shooting into the transfer case so you can spend a good hour or two with a magnet on a stick getting it out. Do not damage the shifter rod end either because those are discontinued as well. Do not use aftermarket flywheel bolts. Or if you do, make sure they are exactly the same dimensions as OEM before you go to install them. I have seen people mention that they got the wrong bolts and it meant having to do the job again. High torque impact wrench makes removal easy. I used some combination of a pry bar and flathead screwdriver to keep the flywheel from turning but consider just buying a proper flywheel lock instead. Just buy the OS Giken clutch alignment tool from RHDJapan. I hated the plastic alignment tool and you will never be confident this thing will work as intended. Don't forget to install the Nismo provided clutch fork boot. Otherwise it will make unearthly noises when you press the clutch pedal as it says on the little installation sheet in Japanese. Also, on both initial disassembly and assembly you must follow torque sequence for the pressure plate bolts. For some reason the Nismo directions tell you to put in the smaller 3 bolts last. I would not do this. Fully insert and thread those bolts to the end first, then tighten the other larger pressure plate bolts according to torque sequence. Then at the end you can also torque these 3 smaller bolts. Doing it the other way can cause these bolts to bind and the whole thing won't fit as it should. Hope this helps someone out there.
×
×
  • Create New...