stock ecu (can it handle boost)?

[NismOmanS15]

alright um almost done with my ka24de+t project all thats left is a ecu and fuel management. im using a t3. alright i need to know if my 96 ecu will accept boost . like will it cut off once the turbo starts spooling. another question how much boost can you run with stock fuel injectors , rail, and pump?one more question does any body know a good ecu setup that doesnt involve me spending $575 on a jwt ecu. thanks <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/cry.gif" border="0" valign="absmiddle" alt=''>

[uiuc240]

The stock ECU will read positive manifold pressure. &nbsp;The main thing to consider is the flow potential of the MAFS...which you won't max out. &nbsp;You'll max out the injectors first. &nbsp;They are just 270cc. &nbsp;You shouldn't really go much further than 7 psi on them. &nbsp;Even that is pushing it. &nbsp;I'd stick with 5 psi until you can get better injectors, a Z32 MAFS and an ECU tune. &nbsp;Oh, and the stock pump will be OK at 5 psi too...upgrade that when you do the rest. &nbsp;The JWT ECU is actually a good deal for the amount of reliability you get. &nbsp;If you want, you can get an S-AFC to tune for 370cc injectors and a Z32 MAFS, but why? &nbsp;For a couple hundred more, you can get a JWT tune. &nbsp;Just drop the real money and get a real ride. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=''>

Eric

[NismOmanS15]

thanks for such a quick reply. jim wolf technology's said i needed to upgrade my fuel rail also &nbsp;if i do that then what should i up grade it too.what about using 470cc injectors(i think thats the number or whatever the 400 series of injectors are can i use those? &nbsp;also so my stock ecu and injectors will be able to send enough fuel to support a t3 at 6psi? also has any body heard about greddy's (piggy back unit) sort of like a stand alone.. if so how has that been for you. well thanks for all the answers i cant wait to get up to par and join the ranks of the turbo 240's :!:

[Kreator]

Well, i dunnow about 6psi, bu i think jeff240sx on this forum is running it at 5psi with stock injectors and stock ecu. Basicly the way ecu works, is it gets the code from the mafs and outputs the corresponding fuel amount. Since stock cars have no turbo, the ecu isn't encoded that far to support the turbo mafs readings.

I'd go with ecu/injectors setup, but there are other cheaper ways you can get around. Yet worse.

You don't have to buy jwt's fuel rail. SR upgrade injectors that are being sold at heavy throttle and on ebay sometimes will i think drop right in.

[NismOmanS15]

thanks for all your help this opens up more ideas on how to tune my car i appriciate all ya'll have done and i will keep ya'll updated on how it works
thanks again.
john.g

[fast-datsun]

You can get away with anything for awhile, but why risk the motor?? &nbsp;Go with the JWT mods and be safe and save the motor!!!!! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/satisfied.gif" border="0" valign="absmiddle" alt=':satisfied:'>

[240racer]

your stock ecu will not have to be replaced to run 7psi. &nbsp;The Mafs will do just fine with 7psi, it doesn't need to be replaced till you go higher, like 10psi or so. &nbsp;The only reason that it needs to be replaced is because the air flow is higher then it is designed to measure. &nbsp;Your stock fuel pump is also fine until 10psi of boost. &nbsp;However, you fuel injectors are not large enough to support the power you will make with 7psi. &nbsp;Even if they were open all the time, they would not inject enough fuel. &nbsp;There are many ways to deal with this. &nbsp;In general there are two main ways to go about getting more fuel. &nbsp;One, you can put larger injectors in (370cc/min or larger). &nbsp;If you do this, then you must let the ecu know about it, or it will always inject more fuel then you need, since it thinks you have smaller injectors. &nbsp;You can have somebody make a reprogrammed ecu so the ecu knows you have larger injectors and it injects the fuel properly. &nbsp;These ecu's are generic and not tuned to your car. &nbsp;They are the safest way to go, but won't always make the most power. &nbsp;This is the JWT reprogram method. &nbsp;Otherwise, You can get a piggy-back unit like the S-AFC to fool the stock ecu into thinking that less air is going in then really is, so it injects less fuel (but since you have larger injectors, it evens out) &nbsp;This is the method I have chosen for my car. &nbsp;I haven't had a chance to to tune it yet, but so far it works great. &nbsp;I can control the idle or off-throttle mixture at 8 rpm increments and the full-throttle mixture at those 8 rpms. &nbsp;So as you can probably tell, you need to know something about tuning engines or bring you car to somebody who knows how to tune engines to go this route (that is why everbody who doesn't know better gets the JWT) There are small variations on the two above methods of using larger fuel injectors (like stand-alone) but those are pretty much your main option. &nbsp;I have yet to talk to anybody who actually had JWT tune their car for them, instead of sending a generic 240sx turbo ecu in the mail. &nbsp;I don't want to bash JWT too much, what they do is good and it works, it just might not be the best method of getting the most power out of your setup and money.
The other method of getting more fuel is a rising rate fuel pressure regulator. &nbsp;This is a unit that controls the fuel pressure relative to boost. &nbsp;the more boost, the more fuel pressure. &nbsp;That way you can run the stock injectors to about 7psi. &nbsp;This is the route nsport has chosen for their kits. &nbsp;You can tune it similar to the s-afc. &nbsp;I don't really like this method because of the consistancy. &nbsp;Also, you probably need a high pressure fuel pump to use this method since fuel pressures might get as high as 80psi.

As far as fuel rails go, if you get DE or SR injectors then you don't need a fuel rail. &nbsp;if you get generic injectors (from jwt or anybody else) then you need a fuel rail that accomidates them. &nbsp;You can get injectors to fit your rail from heavythrottle.com

if you are going to go with JWT (not a bad idea if you don't want to mess with stuff) then get everything at once. &nbsp;fuel pump, injectors, and MAFS. that way you don't have to pay reprogram charges later (one thing I never have to do with the S-AFC)
hope this helps

[Jeff240sx]

Yeah... I'm running 4.35 psi on the stock injectors, ecu, and pump. &nbsp;With a t3/4. &nbsp;Anyway, if you are out of cash, and needed to run 7 psi on stock stuff, you could get a rising rate fuel pressure regulator. &nbsp;They are like $80, and then some dyno time to tune it. &nbsp;That is about the safe limit of a stock KA. &nbsp;After that, you'll need larger injectors. &nbsp;To run larger injectors, you need a JWT ecu. &nbsp;And don't take the companies word on what you need. &nbsp;You don't need a fuel rail untill a lot more boost. &nbsp;And with their fuel rail, you need to run different injectors. &nbsp;Which means you can't buy cheap used SR20DET injectors, which would normally just drop in. &nbsp;
You will really need to do some thinking about your goals and such.
-Jeff