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JDM 2JZ-GTE A/F at boost levels greater than 14psi

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Old 03-08-11, 04:10 PM   #31
Ali SC3
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To the person asking about using 550's you will run very rich in open loop unless you run mad amounts of boost.

The cheapest way to get 18 psi on this ecu relatively safe is with the 550's and scaling back the map voltage (or just install a 2.5 bar map sensor), the timing is only increased slightly. The larger the injectors the worse it gets, but I have heard that with 550's its an acceptable amount of timing bump as the stock ecu is tuned very conservatively. install more than 550's on a jdm ecu and you are playing with fire. Instead of re-explaining it all I will quote my other post from my tt ecu mod thread found here
http://www.clublexus.com/forums/sc-4...db1-sc3-2.html

Quote:
Originally Posted by Ali SC3 View Post
I think the whole beauty of this setup is the ability to use stock everything.
there are many different combos people run, some are good for street, some are only good for drag that you would never think of driving on the street, and some are dyno queens with unrealistically large injectors and map sensors that work on WOT, but good luck trying to parallel park that beast.

a gm 3 bar is doable, but it will put you in more aggressive timing in boost and your idle may suffer, and if you think about it its unecessary to take this trade off.
max you will ever want to run on this type of ecu is 20psi, and a 2.5 bar motorolla map sensor you can order from digikey costs $14 and will work perfectly for this ecu (protect it from heat though it is fragile).
http://dk.digikey.com/scripts/DkSear...s=MPX4250AP-ND
If you can live under 16 psi, use the stock TT map sensor and your car will run the best.

a 2.3 bar map sensor to a 2.5 bar map sensor is around a 15% change in boost load.
you take 1 bar off for vacuum so (1.5/1.3) = 1.15 so you will have to run about 15% more fuel and your timing at 20 psi will effectively be your timing at 17 psi.
550cc injectors is roughly 20-25% more fuel than 440's so this would be a close match that will run a little rich with a good trade off in timing increase.

now a 2.3 to a 3 bar map sensor is a 53% change in boost load. while this can be corrected for in terms of fuel, your timing difference now for 20 psi is closer to 9 psi and for me that us unacceptable.
This is the reason you don't see street cars running over 20 psi on a gte ecu, and if they are they have a lot of other add ons to get it there = $$$, and at that point everyone just goes standalone.

So match the specs as closely as you can to the stock gte ecu and your car will run that much better. 18 psi is more than enough for most na-t street cars, and you get the benefits of a stock ecu, which means great start, great idle etc.. etc...

lol, quickgs is right i probably won't do the TT ecu now that i have mastered my AEM, but It would be cool to test it out sometime. maybe some dyno pulls on both ecu's next year would make an interesting comparison.

**edit**
I forgot to say using an safc changes the load signal as well, so if you use a 3 bar map sensor and the 440cc injectors on a jdm ecu, you would basically be using the safc to add in more fuel (which amplified the load signal) because it sees 58% less load now and effectively making the ecu think its looking at a 2.3 bar map sensor. the problem is that this setup you still haven't raised your boost cut any you now have alot of redundant stuff happening to the load signal that would be close to the same as using a TT map sensor without any safc at all.

If you did the 3 bar with an safc and 550cc on the jdm ecu, where to match the fueling you will be correcting the load to that of around a 2.5-2.7 bar map sensor, that could work but you kind of start to see how unecessary the safc really is if you choose the right map sensor/ injectors, in this example a 2.5-2.7 bar map sensor.
This scenario is completely scalable, increase the map and increase the injectors, but its up to you to decide when your timing reaches what you consider an unsafe difference, and as you see from the calculations going from a 2.5 bar to a 3 bar is a 15% change to a 58% change.
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Old 03-08-11, 05:47 PM   #32
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Quote:
stockhatch You got a CEL from cranking base fp?
No ever since I did the swap, its a CEL i get randomly when I boost and usualy when the cars not warmed up all the way, a little more driving and it just goes away. Ive yet to check the code. Doesn't really bother me the car still performs the same way.

Quote:
Ali SC3 To the person asking about using 550's you will run very rich in open loop unless you run mad amounts of boost.

The cheapest way to get 18 psi on this ecu relatively safe is with the 550's and scaling back the map voltage (or just install a 2.5 bar map sensor), the timing is only increased slightly. The larger the injectors the worse it gets, but I have heard that with 550's its an acceptable amount of timing bump as the stock ecu is tuned very conservatively. install more than 550's on a jdm ecu and you are playing with fire. Instead of re-explaining it all I will quote my other post from my tt ecu mod thread found here
http://www.clublexus.com/forums/sc-4...db1-sc3-2.html
Thanks for the input ALi I didn't know you could buy different bar map sensors, thats the route I might take try and purchase some high imp 550s and 2.5map and try it out. Didn't know the ECU could accept that.
I just want to avoid buying an safc for now and get a decent street setup till I go full standalone.
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Old 03-08-11, 06:01 PM   #33
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Quote:
Originally Posted by SC51 View Post
No ever since I did the swap, its a CEL i get randomly when I boost and usualy when the cars not warmed up all the way, a little more driving and it just goes away. Ive yet to check the code. Doesn't really bother me the car still performs the same way.



Thanks for the input ALi I didn't know you could buy different bar map sensors, thats the route I might take try and purchase some high imp 550s and 2.5map and try it out. Didn't know the ECU could accept that.
I just want to avoid buying an safc for now and get a decent street setup till I go full standalone.

Oh ok. Well at any rate, 10.2 AFR with those boost numbers on a single is really good. I may look into a regulator and see how far the 440s will take me before I go 550. I am not in a huge hurry to hack my wiring for the resistor box etc.
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Old 07-30-11, 09:50 PM   #34
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Quote:
Ali SC3 To the person asking about using 550's you will run very rich in open loop unless you run mad amounts of boost.

The cheapest way to get 18 psi on this ecu relatively safe is with the 550's and scaling back the map voltage (or just install a 2.5 bar map sensor), the timing is only increased slightly. The larger the injectors the worse it gets, but I have heard that with 550's its an acceptable amount of timing bump as the stock ecu is tuned very conservatively. install more than 550's on a jdm ecu and you are playing with fire. Instead of re-explaining it all I will quote my other post from my tt ecu mod thread found here
http://www.clublexus.com/forums/sc-4...db1-sc3-2.html

Quote:
Originally Posted by Ali SC3 View Post
I think the whole beauty of this setup is the ability to use stock everything.
there are many different combos people run, some are good for street, some are only good for drag that you would never think of driving on the street, and some are dyno queens with unrealistically large injectors and map sensors that work on WOT, but good luck trying to parallel park that beast.

a gm 3 bar is doable, but it will put you in more aggressive timing in boost and your idle may suffer, and if you think about it its unecessary to take this trade off.
max you will ever want to run on this type of ecu is 20psi, and a 2.5 bar motorolla map sensor you can order from digikey costs $14 and will work perfectly for this ecu (protect it from heat though it is fragile).
http://dk.digikey.com/scripts/DkSear...s=MPX4250AP-ND
If you can live under 16 psi, use the stock TT map sensor and your car will run the best.

a 2.3 bar map sensor to a 2.5 bar map sensor is around a 15% change in boost load.
you take 1 bar off for vacuum so (1.5/1.3) = 1.15 so you will have to run about 15% more fuel and your timing at 20 psi will effectively be your timing at 17 psi.
550cc injectors is roughly 20-25% more fuel than 440's so this would be a close match that will run a little rich with a good trade off in timing increase.

now a 2.3 to a 3 bar map sensor is a 53% change in boost load. while this can be corrected for in terms of fuel, your timing difference now for 20 psi is closer to 9 psi and for me that us unacceptable.
This is the reason you don't see street cars running over 20 psi on a gte ecu, and if they are they have a lot of other add ons to get it there = $$$, and at that point everyone just goes standalone.

So match the specs as closely as you can to the stock gte ecu and your car will run that much better. 18 psi is more than enough for most na-t street cars, and you get the benefits of a stock ecu, which means great start, great idle etc.. etc...

lol, quickgs is right i probably won't do the TT ecu now that i have mastered my AEM, but It would be cool to test it out sometime. maybe some dyno pulls on both ecu's next year would make an interesting comparison.

**edit**
I forgot to say using an safc changes the load signal as well, so if you use a 3 bar map sensor and the 440cc injectors on a jdm ecu, you would basically be using the safc to add in more fuel (which amplified the load signal) because it sees 58% less load now and effectively making the ecu think its looking at a 2.3 bar map sensor. the problem is that this setup you still haven't raised your boost cut any you now have alot of redundant stuff happening to the load signal that would be close to the same as using a TT map sensor without any safc at all.

If you did the 3 bar with an safc and 550cc on the jdm ecu, where to match the fueling you will be correcting the load to that of around a 2.5-2.7 bar map sensor, that could work but you kind of start to see how unecessary the safc really is if you choose the right map sensor/ injectors, in this example a 2.5-2.7 bar map sensor.
This scenario is completely scalable, increase the map and increase the injectors, but its up to you to decide when your timing reaches what you consider an unsafe difference, and as you see from the calculations going from a 2.5 bar to a 3 bar is a 15% change to a 58% change.
Hey Ali, is there a writeup or something on how/where to install the 2.5 map sensor? I really cant find anything out there. Does it take the place of the stock one?
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Old 08-01-11, 07:24 AM   #35
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Or anyone who knows how to install one to enlighten me please
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Old 08-01-11, 02:54 PM   #36
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havent been online in a few days.
yes it replaces the stock one which has 3 wires.

One is sensor ground, one is sensor signal, and one is sensor voltage (i want to say 5v).

all the map sensors you are going to find have 3 wires. you just cut off the old map sensor (leave enough wire in case you want to reattach later) and make a connector to the new map sensor or you can just hardwire it in if you like. I like to use weatherpack connectors when im doing connector mods, I crimp, then I solder, works perfect everytime.

this image is for a na-t, but it gives you an idea of the map sensor and the 3 wires. pin# @ ecu is same for GTE and NA-T. 62B is the signal wire for the map sensor.
all 3 wires on yours will already be run to the map sensor. much easier to change out.
Click the image to open in full size.
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Old 08-01-11, 09:16 PM   #37
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You the man Ali! I guess I'll go ahead and purchase Ya it confused me because that link you posted, the map sensor looks to have 6 pins. I wonder if its labeled on the map what the pins are for or which ones don't need to be used?
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Old 08-02-11, 08:38 AM   #38
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if you are talking about the digikey one it needs a little computer fan connector (cut off an old computer fan or similar) and the pins are labeled in the manual i believe.
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Old 08-02-11, 12:19 PM   #39
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^alright cool I guess I;ll give it a shot when I get my 550s and resistor pack. Only thing that seems weird to me is that the stock map sensor retails for like 200+ dollars. This thing is 14$ Lol I wonder why that is..
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Old 08-02-11, 12:59 PM   #40
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markup can be cruel sometimes for things that are plug and play.
if you know what you are looking for, its actually a very simple sensor.

i found a thread with the pinout on it. seems like the corvette guys are in on it also. enjoy.
http://forums.corvetteforum.com/c6-f...nsor-pics.html
Click the image to open in full size.
connector looks something like this. you can also use a 3 or 4 pin connector as you only need to use the first 3 pins.
Click the image to open in full size.
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Old 08-02-11, 02:40 PM   #41
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That looks familiar. I would bet that's the same MAP I used on my Megasquirt setup
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Old 12-11-11, 05:23 PM   #42
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Just an update for informational purposes...I raised my boost to 16-17psi and I am out of fuel. In 3rd gear, I have a small range where AFRs climb to nearly 12:1. This is on totally stock jdm fuel and no piggyback, with a single 255 walbro. Now I hate that I sold my 550s
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Old 12-11-11, 05:37 PM   #43
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im almost done with my aristo swap, i will be running usdm turbos,550cc intectors, stock jdm ecu. usdm cams. i have a safc2 laying around which is brand new. do you guys think the car will start ok with out anything and run ok, or will it be to rich and not driveable. only reason i did not install the safc2 is because i dont know how to tune it. anyone have any advise or should i leave it as is and see what happens. i have a wideband to monitor the AFR's. any advise would be great
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Old 12-11-11, 06:00 PM   #44
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stockhatch Just an update for informational purposes...I raised my boost to 16-17psi and I am out of fuel. In 3rd gear, I have a small range where AFRs climb to nearly 12:1. This is on totally stock jdm fuel and no piggyback, with a single 255 walbro. Now I hate that I sold my 550s
That seems to be the boost point where most guys run out fuel around. I dunno I still havn't experienced and WOT A/F numbers going above 11.1 and thats at 20psi. I still want to do the new map sensor and 550's and update, Ive just been busy getting the quad ready for motocross.

Quote:
97-SC300 im almost done with my aristo swap, i will be running usdm turbos,550cc intectors, stock jdm ecu. usdm cams. i have a safc2 laying around which is brand new. do you guys think the car will start ok with out anything and run ok, or will it be to rich and not driveable. only reason i did not install the safc2 is because i dont know how to tune it. anyone have any advise or should i leave it as is and see what happens. i have a wideband to monitor the AFR's. any advise would be great
You'll really just have to try and see my guess is it will start up fine. And once you get used to an SAFC there very easy to use, just don't go to crazy with them.
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Old 12-11-11, 07:24 PM   #45
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People have run 550s on the jdm ecu without a piggyback, it is driveable but you will be running very rich.

There is not much tuning to a safc, especially just for change in injector size.
you basically just set it to take out like 10-20% across the board, the o2s will take care of regular driving.
You should really get a wideband, then you will know exactly what % to take out for open loop or WOT.
Also installing the wideband a week before your injectors is nice, so you have afr's to compare to when dialing in the % for your new injectors.
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Old 12-11-11, 07:24 PM
 
 
 
 
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