My car is a '95 Fed-spec with the original (auto) ECU. I have a full DE-K swap, Cattman Y-pipe, WSP 2.5" high-flow cat, and a custom CAI. I am looking for a little help with fuel economy when I am on the gas in addition to a little smoothing out of what seems like a fairly inconsistent power curve below 4k (according to the butt dyno).

Thoughts on which would be better? If you vote, please tell me why you chose what you chose.

 

I would rather get the VAFC since it is not a cookie cutter method and obviously cheaper.

I have the JWT and did notice a 2-3 MPG increase, and of course a bit more midrange, but for the timeframe and price.... I would rather go another route.

VAFC + larger injectors + wbo2 and you could be doing the same(added timing, better a/f) , minus the rev limit.

Or EU + wbo2 and you might be a bit over JWT spending ceiling, but have a helluva lot more control.

 

Neither, get an EU and do your own TIMING and FUEL.

 

AFPR+AFC=mild timming and fuel control, which for the money is not bad at all.

 

404 ERROR, relevance not found.

 

I drive a lot (~30k miles/year), so 2-3 mpg would be huge.

Price is definitely a sticking point, though. I might be able to get the AFC for $150 and have it installed and tuned for $200, so that is by far the most economical choice. There is also a possibility that I could get a JWT ECU for not much more than that, so that's the only reason that is in the running; the rev limit is not something I can justify paying for, but the ease of installation definitely is. My car will probably not see any more serious performance mods, so an AFPR would be unnecessary. An EU + install + tuning would be WAY off the map in terms of price.

 

This is true, but to do it right, do it on your own, and monitor it w/ a wbo2...
smart choice > economical choice


. many orgers who have had the JWt have seen some unsafe lean a/f readings at the right side of the tach (6000+)


. You might not have understood the point. One can advance timing slightly with higher fp+ MAF conditioning no matter what mods are installed.

Most who want to save and know what they're doing to their cars will tune on their own and install the same way.

 

Wow. Good point. Sorry I missed that.

I do almost all my own mods and maintenance. The only exceptions are tranny swaps, the motor swap, and body work. I just feel a little squeamish about doing the amount of tinkering that an EU requires on my daily driver when I don't have a beater. Besides, for just the price of the EU itself I could have the AFC and AFPR, a lot of dyno time, and some booze. Correct me if I'm wrong, but considering that, and the greater amount of dyno time needed to tune an EU, I don't think the gains would really be justified...


Another point in favor of the VAFC-II that I forgot to mention is that it would allow me to sell my MSD RPM window switch and recover some of the cost.

 

AFPR from SR20 forum is about $40, add a gauge for about $20. Toss in the VAFC and call it a day.

 

Got link(s)?

 

OEM regulators converted:
http://www.sr20forum.com/showthread....highlight=afpr
I am sending him a bunch to be converted, the low port one looks like it should fit. pix on page 6 IIRC. I assume he could take the Maxima one and do the same just to make sure it fitts 100%. Wait a week and I should have mine installed anyhow.
One guy selling the tee and gauge:
http://www.sr20forum.com/showthread....ght=fuel+gauge
Hes sold many, only issue is the fittings are slightly larger than the stock fuel line so elbow grease is needed.
There is also another guy:
http://www.sr20forum.com/showthread....ure+gauge+ebay
seems like a deal, but the stuff looks to be had at lowes/homedepot

 

i am with Sutter....APFR and SAFC or VAFC......i have a question though...coudl u get more timing from injectors or AFPR.....or is it comprable

 

FYI the low port sr20 FPR fits fine. I installed mine yesterday. The high port one has a 90* bend which probably not work with out car. Im talking with the guy about converting the vq30 ones since they look very similar.

 

So I suppose the idea then is to just turn the duty cycle down while equaling out the lack of fuel by raising the fp, thus the computer advances timing because it thinks its running less fuel?

 

Exactly.





10bits

 

Emanage Ultimate like Kevlo said...

 

V-AFC II worth it if I'm only running 4th rails and injectors for my swap?

 

I would say get the V-AFCII and tune it the way YOUR car is setup...unlike JWT running of a generic map (which is known to run dangerously lean in some cases)...

It's realy easy to use....I tuned it myself using a WB02 and it only took me 4 runs to get a completely flat 13.1:1 AFR

 

I was just getting ready to order the JWT ECU (next week), with an added module to control 00VI (a mod I'm planning in the spring), but I like the idea of using a laptop and EU. Do I have to do dyno time, or can I match or beat JWT with EU by just messing with it? Will it override the rev limit?

 

Explain 'just messing' with it. EU isn't for someone messing around. Get a wideband and street tune it if you don't want to go to a dyno.
If you're referring to the EU, then yes, the EU can do that.

 

By "just messing" with it, I'm referring to street tuning. Are you saying you can’t street tune with EU? In post #2 you said “EU + wbo2 and you might be a bit over JWT spending ceiling, but have a helluva lot more control.” I’m considering this idea compared with 1) JWT or 2) VAFC + larger injectors + wbo2, but I need to know if I have to dyno tune to make it worth it.

Also I want to plan for the future. All I have is exhaust and intake mods for now, but I’m planning an 00VI in the spring or summer. JWT can put a module on the chip for me at no extra cost to control the 00VI switching (supposedly uses more inputs than just RPM). Maybe all I need is the JWT with the switching module? If that gets me 90 to 95% of what can be gain by timing and A/F changes, then that would be fine for me (assuming this high rpm leaning effect you mentioned is not a big deal).

The bottom line for me is that the additional cost over VAFC + larger injectors + wbo2 (plus an rpm switch later) doesn’t bother me. And if EU is street tunable, can get me a good bit beyond the JWT setup at whatever mod config I’m at through street tuning, and/or allow me to tune it up on the fly for additional power on non-pump gas, then I want to consider that.

 

If you use a Vafc than you won't need a rpm switch. The Vafc has the ability to open the 00vi valve.

 

Never said that because it's not true.

Eu is street tuneable since most likely you will use any of the aftermarket wb's that are currently used with any other piggyback set-up.

 

Thanks guys. I’m learning a lot. VAFC is sounding better to me with each post too, not to mention the poll stats. I was planning to send in a 95 man trans fed spec ECU to JWT next week, now I'm leaning VAFC. Sounds cheap and effective. I think I'm basically trying to decide between VAFC and EU now, although the low cost of VAFC means I could do it and later move to EU if needed.

I have to say I'm intrigued by EU and the possibility of directly tuning timing and A/F without having to trick the computer with maf signals and change injectors to get the most out of it. Plus, I would like real time tune capability based on what kind of fuel I'm running (either 93 or higher), although I don't know if there is any upward tune for our cars beyond 93 octane, or if EU and/or VAFC can do that.

However, the bigger injectors are part of larger issue. On the one hand, I understand the concept of why they are needed (pulsewidth) for VAFC tune, but not when they add value, and then how much value. Are there any gains for non-00VI NA? Plus, this leaning out with JWT above 6000 rpm, I wonder if injector size is limiting their tuning in the upper part of the rev band? Why so lean?

On the other hand, I am planning to add the 00VI. So when I go to 00VI I have to decide on which LM and fuel rail. If the injector size is just a tuning technology issue solved by EU, then I could just do the UM and leave the 4th gen lower and injectors in place. After considering it a while this looks like that is the easiest way to go (I’m leaning toward option 7 on Tantanko’s list), all things considered. But if fuel flow is a bottleneck in the tune with either USIM or 00VI, aside from its use for tuning with VAFC, that will affect my decision on EU. In other words, if I need to upgrade injectors anyway, why not just stay with VAFC and play with injector size and FP.

 

Stock injectors are fine if you do not plan on upgrading to F/I.

 

I would like to interject the idea of the E-blue,+Wb02. The setup would cost close maybe a little more (depending on how you shop), a little more than the VAFCII +wbo2 but can produce better results.

Eblue has can tune better (adjusting injectors > tricking the MAF), more points for tuning (not sure how many more). add a WBo2 (you wouldnt need to get a datalogging one like you would for the VAFCII so thats money saved), and the eblue will data log the wbo2 for you. Also the eblue can control the manifold so its out classes the VAFC/SAFC.

the downside for some is they dont have the AFC mounted in the console/dash for people to see and wonder what it is.