[Guest]

I am wanting to add a turbo to my '93 NX2000, and I have looked for info deep into the list archives but couldn't find anything of much use. From what I gather, I will need at least the following: T3 Turbo, stock turbo manifold, intercooler, 3" exhaust, bypass/blowoff valve, 370cc injectors, and an ECU upgrade. Now, it seems everyone says the ECU is a MUST, but a few people have suggested other methods such as a fuel pressure regulator... now, my question is: why exactly does the ECU need upgrading if it is such a good ecu to start with? Won't the mass air adjust everything pretty much? and if not, what will happen without the ecu upgrade? Any input on this appreciated! Thanks!

 

[Ben]

I believe the stock ECU can only map the air/fuel ratios so high. With a turbo you will run out of fuel map I believe. That's where the new ECU is needed.

 

[Subculture]

With forced induction via turbocharger, an upgraded ECU is a MUST. Especially with larger injectors.The OE fuel/air ratio maps won't do! Under boost your engine will require extra fuel in order to make the HP. If it doesn't get it then it'll go BOOM! I've seen motors that went lean unbder boost.It's an experience that won't leave you with a warm fuzzy feeling.

If you can afford it, a turbo kit from either F-Maxx, JWT, or HotShot will make very reliable HP. There are a number of SE-R's/NX's with the above turbo systems making 250+HP at the wheels, and are daily driven.

 

[brian]

well, there is a good chance you will lean out your engine. the intercooler and the 3" exhaust is not a must, but good to have, also, if you are not going for big performance gains, I think that you could get away with using the stock injectors, but only on a real low boost system like 5-6 lbs.

 

[Guest]

Can you put subinjectors on the piping to the throttle and control them with a add-on computer instead of changing the main injectors and computer? I think this will be cheaper if it works.

 

[Guest]

Hmmm... ok, I am under the impression that the MAF controls the A/F ratio, so upgrading the MAF should solve the leaning out problem wouldn't it? Or am I not understanding something right? and I will be probably running the T-3 around 13-14 psi.

 

[Subculture]

I think you're missing something.It's the ECU that controls A/F ratio. The MAF tells the ECU how much air is being drawn into the engine. The ECU then tells the injectors how much fuel to flow. If the injectors cant flow the extra fuel, your motor will run lean, with can be disasterous under boost.
Upgrading the MAF won't increase A/F ratio.

I suspect that you're wanting to do a budget turbo system. Nothing wrong with that, but do it wrong and you'll end up spending more money in the long run.

And to answer Erik's question, you could install an additional injector. HOWEVER, the intake manifold on the SR20DE wasn't designed to run "wet". If you were to inject additional fuel in this manner, most of it would end up condensing onto the walls of the intake manifold and dripping into the cylinders instead of being carried in with the intake charge. Which is why you see JWT selling "dry" shot NOS kits for the SR20DE.

 

[Guest]

Subculture: Thanks for the info. I guess the only way is running the JWT computer or investing $$$ for an aftermarket computer. Can I ask you one more question. Can you hook up the computer and wireharness with the MAF from the GTi-R or BB to the SR20DE and get by that way? Sorry to be asking all these Q's.

 

[brian]

I would only do that if you were flowing ALOT of air b/c, well bowlcut is right, it would just drip down into the intake runners and cause more harm than good, but you could run an extra injector though w/ some kind of standalone, I think hks, greddy, or apex sells that kind of thing. I also know on mine (98 model though) I have an extra injector right on top of my intake manifold, so when I start up my car it sprays a little gas into the engine, just to get a little extra, I am not sure about yours though, but it would be cool to be able to get that to kick in w/ the nos

 

[Mike]

I don't think its possible to use a JDM ECU to ru a turbo on the USDM SR20. First you have to use the JDM sensors witch are verry hard to come buy. Second I would think the JDM computers are set to run a turbo engine that is soposed to be 8.5/1 cr. Ours are 9.5/1 cr this could cause a problem.

Just my $.02

 

[Guest]

Thanks for the info... Yes, I would like to do a budget turbo system... =) So, I think I am beginning to understand now... The MAF senses airflow, and if airflow is too high it obviously needs to be replaced with a higher flow rate sensor. This then reports to the ECU, which I assume also takes into account the O2 sensor? The ECU then controls the injectors. And if the reading from the MAF is too high, the ECU has no map for the a/f, so it just uses the highest map is has? This would I assume cause major detonation... So basically all that needs to be done is have the ECU programmed for higher maps? I am trying to figure out some way to avoid the JWT ECU, because its going to cost pretty much about 1/2 as much as all the other components combined.

Anyways, on this same topic... this car was already modified when I bought it, but I have no idea what has been done, except the obvious.. POP charger, borla exhaust, mags/tires, ignition wires. Any ways to check for other mods (like perhaps the ECU?? =) Thanks!

 

[Ben]

Do 93 NX2000s have speed limiters? If they do and yours does not I'd say it has the JWT ECU. Also if anyone here has the JWT ECU, does it have JWT written on the ECU itself?

 

[Guest]

Thats a good way to tell... Hmmm, but I have no idea if its supposed to have a speed limiter or not... Anyone?? I have only had it up to 7500rpm so far though anyways...I would imagine if it had one it would be somewhere between 7500-8000?

 

[Ben]

Nononono, not REV limiter, SPEED limiter. See if you can go over 112MPH and if you can get to like 125 or so, then you might have an aftermarket ECU (or a malfunctioning speed sensor)

 

[Guest]

Ahh, sorry.. I was just thinking about some other cars that are rev limited at 7700rpm... I think I have been up to 115 so far... Anyways, thanks, I will try to get up to 125 shortly. =)

 

[Ben]

Disclaimer:
I am in no way responsible for my advice given. If you are killed in any way shape or form, it's all your fault and not mine

Just saw a post coming back "You made my daddy Jaime go 125 and he got all killed. Thanks mister."

 

[Guest]

Heh heh.. damn, it started raining! Ah well, I will have to wait until tomorrow. =)

Anyways, a friend of mine suggested I buy a DET engine with computer instead, then sell mine, and upgrade the T25 to a T3/T4 hybrid. And cost will probably be about the same, or maybe even a little less than turboing mine properly... Anyone have any experience or input on this? Seems easier to me... not much should need to be done to convert to the bigger turbo.

 

[Subculture]

Okay for the record, to the best of my knowledge NX's do not have speed limiters. If they do it's set at a lot higher than 112 mph.
Okay answers to some questions: Erik JWT uses cobra MAF for applications with high boost. Clark Steppler has the A/F maps all worked out for the Cobra MAF. So forget about the GTI-R MAF. It probly wouldn't work with your ECU anyway.

Shady wrote:"So, I think I am beginning to understand now... The MAF senses airflow, and if airflow is too high it obviously needs to be replaced with a higher flow rate sensor. This then reports to the ECU, which I assume also takes into account the O2 sensor?" Well you're getting there. The ECU does rely on the O2 sensor, but not quite in the way you think. The O2 sensor detects the amount of oxygen (duh) in the exhaust gas. This is how the ECU knows if the motor is running lean or rich.

DET or SR20DE? the eternal debate. Personnaly I'd turbo a SR20. The main reason for this is you KNOW your motor. Buy a DET and it's a crap shoot. You might get a low mileage motor, which would be GREAT! OR, you could end up with a high mileage-worn piston rings-bad main bearings-beater motor. This has happened to a few SR20DE.net LM's.
Just something to consider.

 

[brian]

ya, they use the Cobra maf for all of their high boost stuff, and also I think a maxima one will work, but you will probably pay alot more money for one. also, if you buy a det, just rebuild it, no biggie, just go in and do a little pocket porting, ect and have a really good running motor, it is true that you do not know what you are getting until you get it though, I think the average milege on a det that comes over is around 40k.

 

[Guest]

Ok, but since my engine already has 90k on it, Its likely that I will get a DET that has less mileage on it... are there any problems in upgrading the turbo from a DET to a t3 or t3/t4 hybrid? Will the ECU from the DET be able to handle the extra airflow?