View Full Version : JWT turbo ecu questions

12-10-2001, 10:30 AM
Hi. I am pretty new to the forum and I used to have a 93 civic hatchback with a B18B turbo motor but that caught on fire and that was just the last straw. I recently purchased a 95 240sx with 101k on it. I'm still toying with the ideas of either turboing the KA or swapping in an Sr. However, I really like the idea of factory turbo motors. I have a few questions about the JWT ecu for turbo applications on the KA. Some things I need cleared up are: Does it have a limit to how much boost it can read? Example, if I were to build the KA and want to run in excess of 15 psi, would the ecu know what to do as far as fuel and timing? Does it take out timing based on boost by a predetermined rate? Like X amount of timing taken out every psi? What are the biggest injectors this ecu can handle? I'd like to do standalone such as Haltech but I have never wired one up before and dont have much experience with engine management. Basically I'm wondering if when using a JWT ecu programmed for turbo, is it pretty much the same thing as an ecu on a factory turbo car. Thanks.

'97 S14 SE Turbo
12-10-2001, 10:40 AM
1st thing. Nissan's engine management system uses a MAFS, so reading boost isn't a big issue for the ECU. That only concerns a MAP based management system. FYI, there's also a MAP sensor as part of Nissan's engine management system that can see boost.

So, 5psi, 10psi, 15psi, 20psi, 25psi is all possible on the same proper program.

Biggest injector possible right now is 72lb/hr injectors with use of inline resistors.

As for your final question, yes. It's very much OEM, like it came that way from the factory, until someone notice the "FORD" stamped MAFS (It's a Hitachi Unit. Optional for higher boost levels since the stock MAFS peaks out around 270hp).

There are also other nice options:
1. ECU controlled Nitrous solenoid with built in window for either spool up or full power.
2. Race gas/ Street gas octane switch.
3. Water injection. Not availabe for KA yet.

12-10-2001, 11:13 AM
Haltec vs the JWT. If you are looking for a "factory" style turbo setup. I would go with the JWT. For a 95 it is totally plug and play. Stand alone units like the Haltec or SDS do not preserve most ecu controled options like AC, emissions, ect. Unless you are willing to spend some time to making the two run parallel those will be out of the picture. This could be a big problem if emissions are an issue whre you live.

As far as Stand-alone EMS go the Haltech is one of the most comprehensive and as a result complicated to tune. You will need access to a dyno and some degree of experience to make that setup run well. After looking at a Haltec manual I would not say it is a "first time learn as you go" system.

[ 12-10-2001: Message edited by: uuninja ]

12-10-2001, 11:15 AM
Honestly, I wouldn't recommend the Haltech. I haven't investigated it a lot, but I think it's versatility is kind of limited compared to an Electromotive or Wolf3D system.

If I was going to do a standalone system, I would do Electromotive or Wolf3D. I have just recently been researching these a bit more, and those are the only 2 that I really like.


12-10-2001, 01:00 PM
Is that 400 hp on pump gas?

12-11-2001, 12:45 AM
Ok guys thanks for the prompt replies. Now in reality can the JWT ecu control up to 400 hp IF I wanted to crank up the boost and strengthen the internals? If I were to go the sr route, it would be a red top s13 into an s14 chassis and possibly adding an apex power fc. Now I know there is no do***entation of the wiring of this swap and I notice people on this board are in the process of figuring this out. This car is driven everyday and I would like to retain everything such as power steering, a/c etc. When it comes down to it I could get a used KA motor, take it apart and rebuild it while the current motor is still in the car. Now I know the pistons, rods, manifold and turbo etc would probably end up around the same as a complete sr, so the cost of the used KA being cheaper than an SR isn't really a factor. Also, has anyone done any porting on the KA head on a turbo app.? WE all know this motor wasnt designed for forced induction so I'm curious of the gains. Thanks.

12-11-2001, 12:55 AM
1) There are turbo KA's out there with JWT ECU's running 400+hp at the wheels. 2 that I can think of offhand. One posted his dyno charts today, here.

2) Nobody that I know of has had a turbo KA, dynoed it, replaced the head with one that was ported and polished, and then dynoed again. Because of that, gains are hard to tell. The stock head will work up to 400+hp. Someone ran a 10 sec run with a KA in a 240 with a stock head. That is not to say there aren't gains to be made. If I was going to get a head done, I would probably get it done by the same person who did the 2 400+hp KA turbo heads that I know of.