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Discussion Starter · #1 ·
I have been trying to find a way to get a forced induction system onto our cars. Here is the best idea I have come up with so far to get around the ECU problem:


MSD external coil conversion kit (for Hondas)
Boost regulated fuel pressure riser
MSD boost regulated ignition retard
2nd o2 sensor relocated behind second cat.
6psi max-no intercooler

These items are meant to do what the JWT ECU would do if it existed. I am concerned that there will still be a problem with the ECU trying to fight these mods. Does anyone know if that would occur? I have asked on another board and all they said was to use an older ECU and lose a few emissions devices of little significance. This way was called the "booty" way of doing it--which it is when compared to the turbo JWT ECU. This may be our only alternative if JWT doesn't come thru though. JWT was not intersted in helping determine which ECU pins would need to be moved where to make an older ECU work either.

I'll let you guys pick what turbo you would use. If anyone has an answer it would be GREATLY appreciated
 

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That is totally ghetto......

But I can see why you'd be looking into other options. I could see going that route if you were working on a car that was already turbocharged, you'd probably get much better results.

I could be wrong, but I'm pretty sure you'd trip the MIL lamp with that setup, unless you get lucky enough with the fuel enrichment. Using rising rate regulators and devices that pull out timing can work together, but it's very difficult to tune properly without an ECU. You may have driveability problems at certain RPM's.

Don't get me wrong, I'm sure you could produce more power using this method, just be careful. Invest in an air-fuel ratio meter and watch it like a hawk. As far as which turbo to use.... you said only 6psi so I would favor something small like a T28, assuming you wouldn't want to add any boost later on. This would help with a quick spool-up. All the piping would have to be custom. I'm not sure how the fuel system would react to a regulator. I also am not sure of the limits of the fuel injectors on this version of the SR20.

I'm going to stop typing now. I'm sure the others on this BB will have their own ideas about how this would / wouldn't work. I'm interested in hearing form them.

My vote: NO. Wouldn't try it.
 

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Jdog is rightfully concerned about setting off emissions, however, if you limit the boost to 3-4 psi and be very carefull with the ignition retard curve (BTW, is that MSD box tunable?) you might be able to get away with it. As far as the fuel enrichment goes, I heard that stock injectors should be good for about 190 hp. If this can make you happy, the only thing necessary would be that boost sensitive pressure regulator. Hopefully the stock pump is adequate. The second Gen Turbo Eclipse came with very small T25 turbo, which is good for spoolup. Those guys sell them for cheap when upgrading to 16G or bigger. It seems that an appropriate sized intercooler is necessary to make all this work, simply because there is an intake air temp sensor on our cars, and it might get confused reading 200F.
 

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Discussion Starter · #4 ·
Thanx for the replies. I THINK the MSD ignition box is tunable. I lost the info I had on it. Good point about the air temp too. Maybe water injection before air temp sensor would would work? Either that or an after cooler before the sensor. This is soooo annoying. COME ON JWT!! DO the ECU!!!! :(

I would be happy with 180-190 hp. I don't think I could make it on 3-4 psi tho. Well, maybe with the after cooler. I saw on another board a big long debate about using the S-AFC for the fuel enrichment/tuning. Here's another idea:

S-AFC for the fuel enrichment and to avoid pulling timing
After Cooler or water injection before air temp sensor (if possible)
2nd O2 sensor moved after second cat so the ECU won't freak

What do you guys think of that set-up? :confused:
 

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Discussion Starter · #5 ·
Her's another:

S-AFC to lean out fuel
boost regulated fuel pressure riser
Aftercooler
6 psi max
 

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You may have to do something about the ignition curve. I'd think it would have to be lowered at high boost/high load conditions due to comparatively high compression ratio of sr20de. This probably means that ideally there should be two boxes: one for the fuel enrichment, another for the ignition control. I think that it is possible on low boost applications to omit the ignition controller by enriching the fuel mix at high load. The extra fuel cools the burning process and effectively slows down the combustion. The problems with that are following:
1) this will increase exhaust gas temperature, at a risk of burning exuast valves, gaskets, etc.
2) this will decrease gas mileage enough to notice
3) running richer then optimum will lower the power output.
That third point is because extra cooling will lower peak pressures in the chamber, as well as move the crank angle at wich they occure further after TDC (it is generally accepted that optimum peak pressure angle is ~15 crank degrees after TDC).
All this said, it seems that the best way to acomodate the turbine is by tunning the ECU. I wonder if our ECU is an EPROM type? I am sure that JWT is not the only place capable of modifying a program. If anyone knows anything about our ECU (type, manufacturer, model number...) please post, so we can start searching for someone to tune this thing.
P.S. I am sure that JWT is more then capable of producing high quality performance upgrades, I just dont' see what's the holdup.
 

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Discussion Starter · #7 ·
Nuts, you're right too Artem. I was so busy trying to get around the ECU, I forgot about the rest of the engine. I'm hoping there is something else to do besides an aftermarket ECU (with expensive shop tuning) and a 1997 SR20DE that has been turbo'd. Thanks for the answer.
 

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hey sup!

yes it is possible, timing is a pretty big issue too, but the main would be the ECU, timing at 15 should be fine at 5psi max, I don't think you can go over 5psi, ECU is maxed out around 194.88whp or so. Call JWT and they will be glad to help you out, use a GTI-R setup then run less boost, 4-5psi should be good. any more and I think that would be it for yur engine. You should try also swapping the pistons to stock sr20det pistons, then you can run 5-7psi max. call JWT and ask them they can tell you exact figures, later.
JCC

I am still waiting for the JWT ECU, once that is good the turbo is in, lol. heheh
 

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Discussion Starter · #9 · (Edited)
Ok, stupid questions, which setup? The 1st or second? As for the GTi-R stuff, would that be exh. manifold, correct? I'm just trying to clarify things a little. If JWT doesn't come thru with the ECU, I won't wait for them. I just don't want to call them and then not be able to tell them what I will be using.
I would be happy with 5 psi, but we'll see what can be done.

I need to quit looking around the web. I went to the Apexi website and started to wonder about the S-AFC and their ITC (ignition timing controller)being used in conjunction. The ITC slightly modifies ignition timing. I would imagine it is meant to avoid fighting the ECU. Grrr, questions, questions, and more questions. I hate bugging the pros before I am completely ready to do something, but it appears I may have to. Thanks for the response, not too many people are willing to take on a thread like this.
 

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For the tuning side of things rather than use a combination of interceptors IMO you'd be far far far better off using an aftermarket ecu. Gives you much better control, a much greater margin for safety, considerably better performance and in the end often cost about the same as a collection of interceptors.

There's always the option of burning your own chips as well. Do something like copy the maps from a SR20DET then reatrd a bit all the way through the map. Even better get together as a group, hire some dyno time and a proper air/fuel meter and tune the car properly then burn a bunch of chips. A bit dodgy but should work out cheaper.
 

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Discussion Starter · #11 ·
Welcome aboard IMOA!! Thanks for posting. I think you are right about the aftermarket ECUs. The only downside I can think of is the difficulty of tuning. It seems to require a pro and a dyno? Any tips or suggestions?

For anyone who is wondering, IMAO is an individual who contributed some excellent info on another sentra board about going turbo WITHOUT using JWT parts. It seems they've had some success downunder with alternate routes of computerized engine control. Considering that JWT has yet to do the 98 ECU and this year is almost halfway over, I STRONGLY suggest looking into non JWT engine management.

BTW, I like the chip idea too. I take what you wrote to mean that modified SR20DET maps are downloaded in a way that allows a test vehicle to use them, then be tuned to smooth things out. Is there any other pieces of equipment that would be a good idea to use? I mean computer programs etc. What are the potential downsides to burning/ using a chip? My Sentra won't see more than maybe 6psi, if even that much. I think the chip might be the way to go for me. Any additional details you could provide would be greatly appreciated.
 

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I heard that the chips in the Nissan computers are soldered in. You would have to use some kind of funky solder iron to retreive it. I understand that once the original chip is out an EPROM socket can be installed to ease future changes. Also, what kind of hardware would be necessary to program a chip?
 

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ok, it seems that three things are required to do what IMOA suggests:
1) the chip reader
2) chip emmulator
3) something to program a new chip with.
A PC can probably do all of it, but some attachments and software would be necesary. If anyone knows where to look for that kind of stuff, please post.
 

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Yep, the nissan ecus I've seen have a soldered in chip (bastards). They do have a port for a daughterboard though and they have a proper EPROM sock. I'm not sure whether or not your ecu's are soldered, it's pretty easy to check.

Electrical stores carry EPROM readers/burners etc, you'll just have to play electronics geek for a bit :)

For the software give <A HREF="http://www.mars.dti.ne.jp/~kool/editor_direct.html">this</A> site a try. I'm not sure if your ecus are supported but the software is excellant, and free :)

Personally I really believe your best approach is to order a Haltech from australia. I remember the price was US 1200 odd and that was before the aussie dollar took a dive. To get you running I reckon matt <A HREF="http://www.hitman.hm/haltech.htm">the Hitman</A> will be able to give you a base tune which you can fiddle about with from there. While matt is somewhat a legend in rotary circles he has tuned a lot of SR's and helped with the development of Haltechs new ecus, which just happen to be developed on a SR20DET. In the end I think this approach will be cheaper and have significantly better results.
 

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This makes sence. Thanks for the information. I am off to the Radio Shack to see if any of this hardware is available.
 

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Discussion Starter · #16 ·
Looks like I'll be hitting the computer stores too, but on the weekend. If I find anything, I'll post what I found and where. While I don't have the money to do what I want right now, that doesn't dull the desire. Besides, I want to be ready for when I do have the money. Hell, I'm just happy we have two options to explore that we haven't checked out in detail already. :)
 

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Same here. Its not like I am ready to spend serious bux, but its good to know what can be done. Meanwhile I don't rule out tuning the stosk motor w/out turbo, just to see what kind of perfomance can be achieved.
Its going to be hard to find a good electronics store around here though.
 

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Discussion Starter · #18 · (Edited)
Here is the website link IMOA posted.

www.mars.dti.ne.jp/~kool/editor_direct.html

It has Rom editor which we will need to modify the DET fuel maps, plus I think it has the ECU info we need too. I'll keep looking. Who knows, we may be able to start a special B15 Sentra Net Performance parts group. IF we can pull off the chip thing, turbo and non turbo. That would be a start. If all of that goes well, we could move on to the Haltech with some custom programs to download after they've been tested. Then we could support our BB without having to hit up members for donations by selling the parts through B15 Sentra Net. (sigh)To dream again about car mods. How I've missed doing so.
 

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I've downloaded Matsumoto's editor program and installed it. It looks pretty substantial. I don't know if you've tried it or not, but right now there seems to be a problem with fonts (it gives a bunch question marks for letters). This is an english version, so I am going to look through the settings on this thing, if there are any.
Also, search for "EPROM reader" on GOOGLE brings up this guy Levy Edwards, he has schematics for a ROM reader/burner that works through the LPT1 port, and software for it. Schematics are not killer difficult BTW.
I'll try to get the editor to work...
 
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