Well I talked to Ben at JWT today about my dyno results and A/F ratio. I asked him how well a VAFC or SMT-6 would work with the JWT ECU and nitrous program, and he *obviously* recommended that I send the ECU back to them so they can properly compensate for the larger injectors of the DE-K engine (259 vs 290). I agree with most of what he says, but am unsure if I want to wait another 5 months to get my ECU back He said he will get back to me tomorrow after he talks with the engineer and finds out how long it would take.

Ben thought that with the larger injectors I should be running rich (as did I), but my dyno results show AF between 13-14 most of the graph. JWT recommends 12.5:1 NA and on spray, so the only reason he could think that my AF off is because of the tailpipe sniffer not being as accurate as a real wideband.

Therefore, he also recommended getting a wideband O2 sensor, such as the Innovate Motorsports sensor, to accurately know my AF ratio. He says I could do some datalogging with the wideband, send the info to JWT, and they will reprogram the ECU for the injectors and other small tuning needs that I can find out with a wideband and datalogging.

That all sounds a lot safer and easier than trying to tune with a VAFC/SMT since a reprogram is only $100, as opposed to $250+ for the other units. He said that trying to tune with one of those units won't work perfectly with the JWT ECU, and having a seperate nitrous program only adds to the headaches.

BTW- I do have my stock ECU that I can use for a period of time, but I don't want JWT to know that so they work faster

So here's how it breaks down:
Reprogram- $100
IM O2 sensor- $350
lots of waiting
more accurate and probably power
more $$$ (short term??)

or

VAFC- $250
dyno- $100
Not as accurate AF ratio due to tailpipe sniffer, but can continually adjust parameters and adjust AF ratio if necessary.


After thinking about it, the decision seems pretty obvious (reprogram), but I was looking for some input from you guys. Any tips or ideas?

EDIT- Forgot to add poll....but not really necessary....

 

I really cannot help you too much. But i know from experience the innovative wideband is VERY nice, and thats one of those things that is always kinda of good to have with any boost/juice application. I have an okay amount of experience with subarus (turbo car so its a bit different) but i know with those cars, going with a reprogram is always the best way to go, instead of tuning yourself...self tuning or downloading maps only ends up in 2 things, headaches and blown motors. So, having said that, you love your car. Play it safe. And even worse case scenario ( a 4 month wait) is way better than waiting to save up money to put another motor in your car.

 

used SAFC2 less than $200
no dyno, invest in the wideband - ebay again possibly, and tune yourself for the life of your car & for nitrous.
I thought JWTs program went lean on top end anyways still requiring a fine tune?

 

so you are suggesting he tune himself, off of a dyno? Great idea..

 

That is exactly what I'm suggesting. With a wideband what is the point of a dyno tune? A dyno puts a load on the car just like highway pulls, a tailsniffer won't be as accurate as the wideband...

 

Well that's one thing I was wondering about. I figured I could richen it up with a VAFC, but if I datalog with a wideband and tell them what to do, I figure they could richen it up even better themselves.

Anyone know where I can get a good deal on an IM wideband?

At least with the wideband I can datalog and stuff with no dyno, but I won't be able to adjust anything. That's where JWT comes in....

 

What are your plans? Your readings are good for quick burts, i.e 1/4 mile runs.

Unless you auto cross often then your 13.5:1 is good.. IMO...

 

Well 13.5 might be 'good', but if JWT says I should be at 12.5, then it's 12.5 that I want to be at. I do auto-x, but not very frequently yet. That should change this coming year though. I don't necessarily want it good enough for quick bursts if that means it will affect long-term drivability or other things.

 

JWT doesn't know it all, neither do I but, JWT told me not to do certain things, and I did them anyway, and nothing bad has heppened

 

Not always IMHO. If you want to squeeze the most out of a setup then if you have the know how doing it yourself is what will maximize the power on your car for your specific mods instead of buying the one-size-fits-all cookie cutter solution that everybody and their brother has, but that is only an adequate tune, not a great tune made just for your car. Especially if you have custom or special mods that most don't.

Of course if you don't know what you're doing.. well maybe then it's a different story. Just my 2 cents.



Personally, and as a rule of thumb, I would not take everything that JWT says as gospel. They state their tuning guidelines as applied to the general solution they've determined that works for everyone and they consider to be conservative enough to be safe. But depending on the specific mods on your car, it can be different. BTW, from the dyno-tuning I've done, I have not seen any evidence to suggest that you'll make any better power at 12.5 than at 13.0 or 13.5. You'll just go through more gas. That's talking N/A though... not with nitrous.

 

I didn't see much of a A/F difference witht the 240cc Vs. 290cc injectors with my 2K VI swap. Just make sure you have a test pipe with the wideband pipe test and no other pre-cats in the exhaust. JWT saying their stuff won't work with other tuning devices is kind of a downer but hey that's their way. It's not like Burger King.

I would honestly ditch the JWT stuff and tune with a SMT-6 or Emanage Ultimate. Both units have different tuning maps available so you can setup one for street tune and another for nitrous tune. It won't be easy but you will have the freedom to mod your ECU parameters as you wish.

 

In my opinion, in any car with any sort of power, tuning via pulls down the interstate is NOT the thing to do. Granted yes maximas and subarus are very different (but they are what i know) sure you can buy a turbo xs utec management and make more power road tuning than say using cobb's access port, but i can name at LEAST 7 subaru owners who have blown motors on that form of management who ROAD TUNED off a dyno. If you cant tell im a VERY firm believer in dyno tuning, just because of safety issues. And i couldnt agree with you more that you can squeeze the most power out of your setup by tuning yourself, but for how long? And i wont disagree with you that in some scenarios yes SOME fine tuning MAY be required, but at the same time, is that 10 HP worth it? sure it is at the time..but when you discenegrate a ring land its not so worthwhile. The only major point im trying to make here , is that 4th gear pulls down the interstate ON NITROUS are NOT a good idea.

 

Why would run down the road in 4th gear?

 

higher gears are where your egt's are highest, am i not correct? So, you gonna tune a car in 2nd and 3rd (IF you can even get traction in 2nd) what happends when u lean out in 4th?

 

2nd is too short and 3rd gear is a timebomb.

 

thank you.

 

get an afpr and drop the pressure just a hair.

 

Yeah, I wasn't thinking about the nitrous aspect when tuning.

 

Whoa hold on a sec here I never said anything about ripping down a road in 4th gear. I would still use a dyno to do most of the tuning.

I was only pointing out that if you have specific/custom/non-mass produced mods and want to get the most out of the car, the cookie-cutter solution may be good, but won't be the best possible. It all depends on the person's particular setup and goals. I do respect the fact that not everyone will want to go the more customized, do-it-yourself route. In fact, only the minority do.

But IMO, depending on the mods on the car and the know-how of the tuner, especially on a higher powered car with FI, the difference can be more than just than 10 hp.

 

I agree with you completly, and yes. Sometimes there are mods that mass produced, preset management may not be able to compensate for. Which is where YES you may have to do some street a/f tuning yourself, but a minimal amount. My only point here was tuning a maxima making ( i dont know what kinda power this guy is making) well say near 270 WHP FWD on the street, is just not a good idea. A majority of the time u have to tune a/f's in higher gears (at least in boosted cars(which is what i know)) because thats where your egt's are gonna get the highest, and thats where you are going to have to biggest risk of leaning out and going boom.