max safe power on 1JZ with std injectors and ecu (with FCD)??

[RORZ_JZA70]

Hey guys,

my car has the following mods:

twin HKS T3G turbos on custom high mount tubular manifolds (heat wrapped)
Trust Greddy Adj cam gears (intake and exhaust)
Twin 3" intake, twin pods
Twin 3" split dumps
3" straight thru zorst
600 x 300 x100 FMIC
APEXi Power FC with hand control
Blitz SBC i-D III electronic boost controller
Sard 800cc injectors
Walbro 500hp fuel pump

275KW at the wheels


My power fc appears to be faulty and im sending it back to Japan for warranty. In the meantime I've had to re-install the std ecu and std injectors.

I had it running like this for a while before fitting the pfc. I was only running 12psi because of the overboost cut on the std ecu and making 208KW at the wheels. The AFR's were at about 10:1. Bit rich for my liking.

I'm thinking about getting a FCD defender and maybe a fuel pressure reg as a cheap solution until I get the pfc back. Does anybody know if the AFRs will go richer or leaner as I raise the boost? Obviously any richer than it is now would be unacceptable.

How much power can you safely make with the stock injectors? The car makes 275KW at 20psi, would it be possible to make close to this figure with just a FCD and fuel pressure reg?
__________________

[MR 1JZ]

unlikely, I belive the most you will get out of a stock ecu is about 250rwkw, really though if its running fine on 208 why not wait untill you get your PFC back and then enjoy 275rwkw knowing its going to have a good tune behind it?

[RORZ_JZA70]

Id like it to be leaner than the 10:1 AFRs it has when making 208KWs at 12psi with the std ecu. I'd like to lean it out to around 12:1.

[MR 1JZ]

well then you have to ask yourself a question...is it worth pushing your AFR's to 12:1 via a relatively primitive method all to have a little more power while your power fc is off being repaired?

How much do you value your current pistons?

it runs doesnt it?

208rwkw is nothing to laugh at either...much better than 0rwkw while youre replacing your bottom end

[RORZ_JZA70]

it isn't "pushing" AFRs to 12:1.

12:1 is the ideal AFR ratio. 10:1 is almost dangerously rich. When you run an engine this rich all that fuel can wash the oil off the bores.

[BigWorm]

There really is no way to cheaply & reliably adjust the mixture, even with your idea of FPR & FCD, to do it safely would require some dyno time to set it up properly (ie safely), so you'd be looking at the cost of the hardware plus the tuning.
I am running a homemade FCD on my 1J, which cost no more than $1 to put together, & with this & running 14~15psi it was still hella rich.

You're really better off leaving it as it is (10:1 is pretty normal for a 1J) and waiting to get back the Power FC, or even better flogging it off & installing a decent ECU like an Autronic. Especially considering the list of goodness you have on there.

[RORZ_JZA70]

ive been told the factory ecu only stops putting in aditional fuel at 15psi. So running 14-15psi wouldnt really change it. Running 17psi+ should lean it out nicely. Just trying to find out if anybody else has done it before i put down the coins for the FCD.

The dyno time shouldnt cost much at all. It's not going to take long to slowly wind up the boost while watching the AFRs to make sure it doesnt lean out. Keep adding boost til it hits around 12:1.

Do you want to make another cheap FCD? If it works ill happily give you $20 for it. That's a $19 profit

[BigWorm]

The standard ECU hits fuel cut at 13.5 psi (or around thereabouts), but even then all my dyno runs running more than 13.5 psi (anywhere from 14 to 16~17psi) the AFRs start around 12:1 and taper down to 11:1. Running 11psi it goes from about 11.5:1 to 10.5:1.
So you'd need the sort of boost you're talking about and more to end up with half decent AFRs, and I certainly wouldn't feel safe doing that full time without a proper tune. But hey, I'm not doing it in my car!

I reckon the FPR would be your best bet, at least with this you can adjust the fuel every where, rather than just over the boost cut point. You're really not going to be spending much time over 13~14 psi are you!

I don't have time to make any FCDs ATM, but when I get a chance I may just sit down & whack a few together. I'll let you know if I do.

[ReQuieM]

OK now correct me if I'm wrong, but the point of the FCD is to fool the ecu into thinking it running less boost. It does this by adjusting the map sensor out put. The 1jz has a 1 bar map sensor meaning it outputs a 0-5v based on 0 - 1bar reading. so 0 bar, 0volts. 1 bar, 1 volt. FCD will max the max output of the map sensor to (whatever you set it to, but usualy) 4.7 odd, meaning it reads around 13 psi when ever you go passed 13 psi. Even if the ECU would ad fuel up to 17 PSI it aint gonna know that theres 17psi there cos it can only read to 14.7 (5volts). I highly dobt that it is programed to 17 anyway, thats probably just here-say.

I'm not suggesting this is the correct way to go, as I'd also wait, but you could experiment with using a 1.5 bar map sensor, FCD and FPR with a dyno session. In theory the bigger map sensor should have a broader range while still sending out a 0-5v reading. meaning that at 5volts your ecu would think that its running 14.7 when its actualy running 21, etc, etc. App, (here-say) the 2JZ is a 1.somthing and still sends out a 0-5v reading in the correct direction.

[RORZ_JZA70]

OK now correct me if I'm wrong, but the point of the FCD is to fool the ecu into thinking it running less boost. It does this by adjusting the map sensor out put. The 1jz has a 1 bar map sensor meaning it outputs a 0-5v based on 0 - 1bar reading. so 0 bar, 0volts. 1 bar, 1 volt. FCD will max the max output of the map sensor to (whatever you set it to, but usualy) 4.7 odd, meaning it reads around 13 psi when ever you go passed 13 psi. Even if the ECU would ad fuel up to 17 PSI it aint gonna know that theres 17psi there cos it can only read to 14.7 (5volts). I highly dobt that it is programed to 17 anyway, thats probably just here-say.

Exactly, only reads upto 14psi then stops adding fuel. So more boost over 14psi should lean it out to an acceptable level. Nobody said the stock ecu was programmed to 17psi. I just said that id need to run 17psi+ to lean it out sufficiently.

I

'm not suggesting this is the correct way to go, as I'd also wait, but you could experiment with using a 1.5 bar map sensor, FCD and FPR with a dyno session. In theory the bigger map sensor should have a broader range while still sending out a 0-5v reading. meaning that at 5volts your ecu would think that its running 14.7 when its actualy running 21, etc, etc. App, (here-say) the 2JZ is a 1.somthing and still sends out a 0-5v reading in the correct direction.

I dont see why you'd need the 2J map or the fuel pressure reg. It's already too rich so why would u want a FPR? and with the FCD it should work with the 1J map.

[BigWorm]

Get yourself an adjustable FPR so you can decrease the base fuel pressure.

[ReQuieM]

What BigWorm said. Its the only thing you mentioned that will actualy adjust you fuel delivery amount.

as to the MAP sensor, re-read what i said. Its another way to trick the ecu into thinking its reading a lower boost setting. As in my example if you had a 1.5bar sensor verses the 1 bar sensor, 14.5psi would equal a 5v reading verses a ~3.3v reading. By having the ECU thinking your running less boost you are leaning out the mixture as it's pumping in sufficient fuel for 'lower' boost reading, where you are obviously running more.

Yes a FCD will work on a 1j map sensor.

My appologies, I miss read the 17 PSI fuel map statment.

Also remember the FCD ISNT effecting the fuel in any way. It just allows you to run more boost with out the computer knowing and cutting off the fuel supply.

[RORZ_JZA70]

What BigWorm said. Its the only thing you mentioned that will actualy adjust you fuel delivery amount.

as to the MAP sensor, re-read what i said. Its another way to trick the ecu into thinking its reading a lower boost setting. As in my example if you had a 1.5bar sensor verses the 1 bar sensor, 14.5psi would equal a 5v reading verses a ~3.3v reading. By having the ECU thinking your running less boost you are leaning out the mixture as it's pumping in sufficient fuel for 'lower' boost reading, where you are obviously running more.

Yes a FCD will work on a 1j map sensor.

My appologies, I miss read the 17 PSI fuel map statment.

Also remember the FCD ISNT effecting the fuel in any way. It just allows you to run more boost with out the computer knowing and cutting off the fuel supply.

I understand how the 2J map would work but if it's tricking the ecu into thinking it's running less boost would you still the the FCD?

I'm thinking about just spending the money that would be spent on FCD, FPR on the fastest possible postage to Japan to get the Power FC back.

[chris davey]

2jz map is apparently about 18psi. So you are raising your boost cut to that.

If you go over that then get a $1 FCD

Of just pay the extra for quick postage!

[ReQuieM]

You wont NEED the FCD if your keep the boost under what ever boost setting causes the new map sensor to output 4.7+ volts. So if you use the 2jz map sensor that would be about ~16.5 PSI, over that you'll need the FCD to limit the max volt reading.

Its all a matter of whackin it on the dyno and working out whats gonna work. If you've got an FCD and a rising rate FPR then you could could tweak it out. The 2jz map senor you could use on its own. Just run it on the dyno to make sure you dont lean out to much up top, althou you still be pretty rich down low.

Yo chris thanx for that, I was about to start the search for the exact PSI. + REP