GT2871 USERS. SR motor

[180sxqc]

how are the rom tunes at light throttle, is the curve smooth and the power delivered progressively or again is it only tuned for WOT (thinking of getting JWT tuned ecu soon)

[BlackZenkiS14]

As a solid believer in the JWT tune, I can say it feels fantastic! The light throttle feels like factory, and the power feels very very smooth. Wideband looks great through the whole powerband!

[EsChassisLove]

Originally Posted by inopsey

i like how you say that how dont know how to tune so theres no need to worry about messing up the system with a complicated ecu like aem; but at the same time you are so confident that the aem will net more power than a pfc.

Because that tuner switched JZ engines from Apexi to AEM all the time and with no modsother than the ECU he makes more power.

Can we stop comparing an Atari to a PS3 now? We obviously know which is better

[inopsey]

Originally Posted by Seraphim38

on pump gas I am running 16 degrees for heavy load/full boost at mid to high rpm ranges.

The tuner had set it to be 40 degrees off throttle in the midrange and by setting the controller to show ignition timing and the output of the knock sensor, I found that the max I could run on 92 pump gas without pinging was between 28 and 30 degrees at low load positions.

I am using a Zietronics wideband with the dataloggit setup, and have confirmed that it's output corresponds with the AFR readings on the dyno.

My Injector Dynamics 1000cc injectors never see more than 50% duty, so it's possible that a slightly smaller injector would allow more precision in control (since you have to use an injector scaling with the Power FC that diminishes in effectiveness for larger injectors above 800cc). The scaling is working fine for my setup though.

The light load setup tuning involves logging the AFRs at the 2nd to 14th rows of the map, which essentially are off-boost and should be near 14.7:1. If these points run too lean it results in too much engine deceleration and abrupt throttle response not to mention that it isn't good for the motor. If these points are too rich, which was more the case than not, the engine has to clear the excess fuel before it can spin up. After tuning the low load pionts the engine spools up much faster, thereby feeling less laggy.

I was surprised when I first starting tuning that a slight, quick increase in throttle position caused the engine to go lean because the standalone can't respond quick enough to get fuel in. The map points that the ECU sees are fine when tested as not part of a sudden increase in throttle position. I expected less latency in the system.

Otherwise, if anyone wants me to post screenshots or to help guide them individually through what I have done, I am happy to do so.

i wouldnt mind seeing the before and after after timing maps. what did you use to determine if the engine was pinging?

[Seraphim38]

I don't have a before timing map because I didn't take a screenshot and didn't save a copy to my tuning laptop until I had made the majority of the timing changes.

I set the Power FC Controller to the 4 parameter view setting, and set it to watch Boost Pressure, RPM, Ignition Timing and Knock Sensor output. The knock sensor appears as a bar graph under the Ignition Timing number, so when the ignition timing graph starts to register knock noise it shows right under the corresponding timing number. Also, using FC-edit I was able to datalog and compare ignition timing with knock readings. By the time I started using the dataloggit, I had largely resolved the timing map though.

[codyace]

Originally Posted by EsChassisLove

Because that tuner switched JZ engines from Apexi to AEM all the time and with no modsother than the ECU he makes more power.

Can we stop comparing an Atari to a PS3 now? We obviously know which is better

I've got a harder time beating Castlevania than Modern Warfare?

[EsChassisLove]

That's a valid argument since I still play Castlevania. Lol.

[jaysgottaredtop]

Originally Posted by BlackZenkiS14

As a solid believer in the JWT tune, I can say it feels fantastic! The light throttle feels like factory, and the power feels very very smooth. Wideband looks great through the whole powerband!

i also have a JWT tune, and i 100% agree with this. sums up my experience pretty well.

[Punished]

Question time:

I currently have a top mount, T3 Precision Turbo 6265 AR.82, that while fun as hell, I want something quicker spooling. I'm also on Toda 264/264 cams and 1000cc injectors, fresh stock bottom end with thrust washers and mazworx head studs.

If I switch to the T3 gt2871 AR .64 with my current injectors and cams will this be solid for road race/ drift? Faster response is what I'm after, which I know this turbo will do. Anyone have experience with it on 2654/264 cams? If I can find a buyer for my intake manifold and turbo it will cover the cost of the 2871.

[StepN2Boost]

Posted some questions a while back before my tune here are the results
Mods: 1991 Sr20 redtop, Gt2871r .64 Ar, Aem Ems, 810cc injectors, Fpr, Walbro 255, turboback exhaust, fmic

Blue=14psi
Red=18.5psi


I do have a few issues however. Fuel pressure keeps dropping. Just had brand new pump, lines, filter, injectors, fpr installed. Don't understand. Only thing I can think of is when I picked it up it was on E! I went to take it for first drive and not ten minutes after it was on It popped/melted the pump fuse. I replaced the fuse and went for a short drive, came back and FP dropped to 30psi. So I took it back to the shop that did the work, and they hardlined the pump directly to the battery and used the oem pump relay as a trigger, they said they road tested it and was holding FP just fine. Drove fine on the way home, pulled in the driveway and the FP was at 20psi!

[cotbu]

following your current path, you make about 13.9hp per psi of boost
you're looking at 386hp at 20psi. This Is the middle Average from a gt2871r that i've been seeing. My scale @ 17psi(low 330, middle 350, high 365) Nice work, If I were tuning it I'd try to hit that same hp and tq with 1 less pound of boost!

Anyway if you ran that walbro on E! just replace it and save yourself the headaches!

PS 13.9 + 386 = ???

[StepN2Boost]

Originally Posted by cotbu

following your current path, you make about 13.9hp per psi of boost
you're looking at 386hp at 20psi. This Is the middle Average from a gt2871r that i've been seeing. My scale @ 17psi(low 330, middle 350, high 365) Nice work, If I were tuning it I'd try to hit that same hp and tq with 1 less pound of boost!

Anyway if you ran that walbro on E! just replace it and save yourself the headaches!

PS 13.9 + 386 = ???

When they dyno it at 18.5psi(computer said 18psi but my gauge read 19), they didn't have enough time to let the motor cool so that pull was w/the motor heat soaked. So id actually be making closer to 365. At any rate I'm happy with the turnout.

As for the FP drop, I believe it might be knock off aeromotive fpr that's causing my problems. Going to switch it out with an authentic aeromotive, but I've heard people with Sard Fprs having zero problems and wouldn't recommend any other. So I might just go with the Sard. Any suggestions?

[Seraphim38]

I have the aeromotive 340lph stealth and it is way overkill. I suggest running a power relay direct to the battery for the fuel pump since the stock wiring harness could be starving the pump of voltage.

The factory hard lines are plenty capable of supporting your hp levels, but make sure that you have adequate fuel line under the hood and a decent fuel filter. I run the Aeromtive FPR and it works well, along with a billet Aeromotive fuel filter. The thing is, when you go with legit parts from the start you don't have to guess as to if any of them are failing.

[StepN2Boost]

Originally Posted by Seraphim38

I have the aeromotive 340lph stealth and it is way overkill. I suggest running a power relay direct to the battery for the fuel pump since the stock wiring harness could be starving the pump of voltage.

The factory hard lines are plenty capable of supporting your hp levels, but make sure that you have adequate fuel line under the hood and a decent fuel filter. I run the Aeromtive FPR and it works well, along with a billet Aeromotive fuel filter. The thing is, when you go with legit parts from the start you don't have to guess as to if any of them are failing.

340lph damn that's a big pump. Lol. I already have a power relay irect to the battery with an inline fuse going to the walbro 255, also have brand new softlines al the way through and running the z32 fuel filter. And yes hindsite is 20/20, I should have gone with a legit frp, but even with legit fprs I've seen peep have pressure issues, even nismo fprs have issues. I was just reading about the aeromotve fpr and its psi range is only to 70psi, while the Sard is good to around 120psi(8bar). So I'm leaning towards the sard.

[Seraphim38]

LOL...with bigger injectors you shouldn't need more than 70psi. The more injector flow you have the less fuel pressure you need to get the desired results. It's always better to get more fuel through managed injector flow than through higher fuel pressure.

I doubt you will ever find someone in a street or race application who would say that the Aermotive FPR isn't good enough. It's was overkill for my 32v Mustang Cobra 4.6 liter v8 that ran 21psi of boost...

[cotbu]

Those number quoted were for real a real dyno! jk
Yeah, I'd recommend a genuine Aeromotive fpr

[StepN2Boost]

^^^ I will be doing this, also will be picking up the aeromotive fuel pump seraphim is running. B/c overkill is under rated, and at this point I just want to be done with this.

[AsleepAltima]

i have 87mm pistons, 264 cams, 740cc injectors, walbro 255 (with relayed hot wire) and aeromotive fpr - no issues. 22lbs boost, stock fuel pressure setting and 11.2-12.2 on the wb during full boost. i dont see why anyone would need more than a 255 and an aeromotive fpr with this setup, which is pretty similar to a lot of other peoples setups.

[StepN2Boost]

Yes I have seen many peep running the walbro 255 with a similar setup working well. Which is why I originally went with it in the first place. However, I've also seen many peep and tuners that have said that walbros are hit or miss and aren't reliable as they used to be. Its for this reason that I don't feel that its worth risking my time and further headache on a fuel pump that might inconvenience me in the near future and with my luck at a most unopportuned time. This is my dd.

[AsleepAltima]

Originally Posted by StepN2Boost

Yes I have seen many peep running the walbro 255 with a similar setup working well. Which is why I originally went with it in the first place. However, I've also seen many peep and tuners that have said that walbros are hit or miss and aren't reliable as they used to be. Its for this reason that I don't feel that its worth risking my time and further headache on a fuel pump that might inconvenience me in the near future and with my luck at a most unopportuned time. This is my dd.

mine is a dd too - unless its hot then i drive my evo. lol.
im starting to wonder though, how many people are having problems with their walbros simply because a lot of cars are running around with close to 20 yr old wiring that was never meant to handle the load of a walbro. after the stupid problems i had with mine it turned out to be nothing more than wiring. ive been running a walbro for quite some times in 2 of my cars with no problems ever. maybe they are hit and miss, but i know now that the first thing i will be checking when people say theyre having fuel problems, will be the voltage at the pump.

[StepN2Boost]

I'm guessing you don't have ac in your 240? Haha me neither. Yeah I had wiring issues when I first put it in before hotwiring it, I was melting pump fuses n everything. Lucky a fire wasn't started. Personally I have three friends that went through 1 or 2 walbros before they received a good one and even then they only lasted 1yr-1.5yr before it shitted out on them. Also my tuner says in his experiences they haven't been very reliable, also steve shadows on here says walbros are "Crap". But hey, sounds like you might have gotten lucky!

[AsleepAltima]

Originally Posted by StepN2Boost

I'm guessing you don't have ac in your 240? Haha me neither. Yeah I had wiring issues when I first put it in before hotwiring it, I was melting pump fuses n everything. Lucky a fire wasn't started. Personally I have three friends that went through 1 or 2 walbros before they received a good one and even then they only lasted 1yr-1.5yr before it shitted out on them. Also my tuner says in his experiences they haven't been very reliable, also steve shadows on here says walbros are "Crap". But hey, sounds like you might have gotten lucky!

yeah no ac in the 240 - the previous owner ripped it all out. i might be one of the lucky ones. lol. good thing i have an extra! haha

[zurud]

Originally Posted by StepN2Boost

When they dyno it at 18.5psi(computer said 18psi but my gauge read 19), they didn't have enough time to let the motor cool so that pull was w/the motor heat soaked. So id actually be making closer to 365. At any rate I'm happy with the turnout.

As for the FP drop, I believe it might be knock off aeromotive fpr that's causing my problems. Going to switch it out with an authentic aeromotive, but I've heard people with Sard Fprs having zero problems and wouldn't recommend any other. So I might just go with the Sard. Any suggestions?

Just stay with stock fpr.

[huffandpuff00]

My tuner hooked up my ewg like setup (2). I was lead to think you are supposed to install it like setup (3). Are there any negative effects with hooking up the boost lines that way... (2) vs (3)?

my parts:
AEM boost solenoid
tial MVS



Thanks,
Zac

[cotbu]

If you ever have to question your tuner's decision? You should find another one!

In that configuration, you are bleeding of pressure to control boost! Very ineffective for an external setup, but it does work! You're probably wasting some boost, there.

The Top port is for boost control, and you should be using it, especially with a boost solenoid. The solenoid does dump pressure as it actuates, but it's more to the affect of controlling the duty of already set boost. Probably lost all of you right, there! OK bye bye!

[Kingtal0n]

Originally Posted by Seraphim38

on pump gas I am running 16 degrees for heavy load/full boost at mid to high rpm ranges.

The tuner had set it to be 40 degrees off throttle in the midrange and by setting the controller to show ignition timing and the output of the knock sensor, I found that the max I could run on 92 pump gas without pinging was between 28 and 30 degrees at low load positions.


The light load setup tuning involves logging the AFRs at the 2nd to 14th rows of the map, which essentially are off-boost and should be near 14.7:1. If these points run too lean it results in too much engine deceleration and abrupt throttle response not to mention that it isn't good for the motor. If these points are too rich, which was more the case than not, the engine has to clear the excess fuel before it can spin up. After tuning the low load pionts the engine spools up much faster, thereby feeling less laggy.

I was surprised when I first starting tuning that a slight, quick increase in throttle position caused the engine to go lean because the standalone can't respond quick enough to get fuel in. The map points that the ECU sees are fine when tested as not part of a sudden increase in throttle position. I expected less latency in the system.

Since you have a datalogit, plug the wideband analog output into the black box and configure the auxiliary input. Then download the "tuner" spreadsheet from the datalogit site.
Paste the a/f values you log into the spreadsheet and it will give % changes for "auto correcting" your base map. If you are ambitious you can write a small script to do it for you, and the computer will auto-tune your map while you drive.

#2:
If you are using 93 octane and making over 350 horsepower with a 2.0L sr20det engine, then 16* of timing is probably too much. No, it probably will not show up on the knock sensor either. Around 15-18psi you probably want no more than 10-12* of timing, and you can verify by the dyno graph, reduce timing from your 16 to about 10* and compare the results. If the EGT and torque do not change, the graph may even get smoother, you had too much timing. I just tuned a Supra last week and it surprised me, taking a full 13-14* of timing at 18psi on 93, but VE was dropping madly by redline (the torque was falling off indicating the breathing ability of the engine was failing despite having plenty of compressor).


The engine responds with up to 20ft/lbs and torque everywhere (blue), AND the graph gets smoother. noise graph looks the same, and if we had an EGT sensor I bet the EGT dropped also. I would guess it is around 1300*F, maybe 1270*F would be nice to reconfirm.


So, just to be perfectly clear, 11 or even 9* of timing would have been enough for truly 210+% volumetric efficiency. But in this case, VE is dropping, so the engine responded to a more advanced timing, by 2-3*, with a noticeable improvement in torque output with all safe numbers on every gauge.

Increasing any further yields less power. The final run (red #6) timing was increasing further, just two more degrees. power loss occurs. The extra timing was welcome for spooling the turbo (indeed an ignition timing of 25-15 may be applicable during this time) but it was unwelcome in the higher rpm. The egt probably still looks good and the knock looks similar- SIMILAR but not the same. There is more noise on this graph, although it still looks tame and "knock count" is within considerable boundaries, something is wrong with this setting and the engine is trying to get our @#$&* attention.


Always start conservative and watch for the signs of a healthy engine. I had the A/F nearly sorted out before I even hit the dyno, so that run #4, 5, 6 I was already doing final tweaking, finishing up, In and out with as little wear and tear on the engine as possible. I noticed the dyno loads the engine somewhat more than the vehicle does on the street under it's own weight, so consider that it will get even richer at the same boost pressure once the car gets on the road. I accounted for that for safety- the AEM shows me 11.8's on the dyno and 11.5's on the street. Keep in mind this engine is not topping off it's cylinders at high rpms with air. A set of cams might fix that, this is the bone stock 2jz engine.

[Kingtal0n]

And from tonight, this is a 240sx with a 2871r (84)

This is just a tease. Boost is set to just 12psi. This one should make about 400 when we get the fuel issue sorted out, it was getting lean by just 7,000rpm so we called it a day.

Same graph, one shows uncorrected (zero smoothing)

[koukistylejdm]

Stock SR stock head
2871r(84)
750cc
hmic
3''turbo back
stock manifold
walbro 255lph
c16/91oct-------50/50
343whp at 23psi
on dynapak
tuned with aem ems

[ForeignMuscle]

I'm about to bolt on my setup using the 2871. Oem manis, Atp backside (which im bummed about) Tial mvr, and so on. I've yet to see anything but complaining about the .72 housing, but I'm also only using the car for drag. I don't know what to expect. I'm using S3's and Nistune via 4x4le and e85. Hopefully most of you just need a different powerband and this will work perfect for me. Paging CodyAce...

[ForeignMuscle]

Just looking for any input from someone who knows or has used the .72. I'm thinking the later spool will be fine for the strip but codyace mentioned it has horrible flow. I was under the impression it would allow more top end and shift my powerband to higher rpms which would be useful. I really don't see myself needing any low end grunt at all but I could be wrong.