1.) Ive done a fare amount of searching for this answer and have seen a lot of things saying that you have to put back on your stock intake. Is there that big of an ill effect on your AF? So much so that it will damage your engine?

2.) Has anyone seen any fixes for the early 2003 issues they were having with AF readings?

3.) I understand that the AP costs less than a UTEC, but why not just get a UTEC installed. Correct me if Im wrong, but you'd get better results from what ive read.

 

1) The pop charger actually does increase HP by a small amount. No need to put your stock air box back on. It will help your engine breath a bit better and will not damage your engine at all - the factory ECU can compensate.

2) Someone else can chime on this, have no idea it was even an issue.

3) The AP will allow you to plug into your OBD2 port and tune it from there. Currently it does not support FI but it will eventually. The UTEC can be used for NA and FI at the moment. I think you'll see similar results with either one.

 

At the present the AR does not support intake mods. They suggest not to use it due to causing lean condition. They are working to alleviate the condition in future updates.

 

Thanks for the replies. So has anyone heard of anything coming from Cobb quickly to fix the intake issue? I know that I dont have all the stock intake parts for my car and would think that it could only help.

 

From what I read, various intakes are giving INCONSTANT a/f readings. ie.. stock = x Stillen = xy JWT = xyz CAI = ahsh So what is happening is that they are having trouble developing ONE flash for a car with intake only. Because it depends on WHAT intake you have. And according to Cobb, not all the changes that the intakes gave were positive. Some resulted in a performance LOSS. So instead of having to develope reflash versions for all the intakes out there, they recommend the stock.
Another clue as to the effectiveness of some of these intakes have. If they found one or two that worked well, I imagine they would/will recommend XX brand for YY flash.

 

They're just trying to fix the variable to OEM. If they're going to support even the top 3 most-used intakes on the market, their workload and support issues just increased to 4X just supporting one.

RT tuning is the way to go, if it's static, I don't want it. Even if they fixed the intake to OEM only, cars have enough variability they may just get close, unless the flash is done realtime on your own car. I've been through this with my SR20, KADE24, and in hindsight, I cannot imagine that a single flash tune is going to work w/o tweaking in place on your car. JWT did extensive dyno tuning for my SR20's ECU changes, not just some "here's a chip for SR20's". My KA's is a Calum RT daughterboard.

Maybe I misunderstand what is being sold here, but it sounds like a static flash w/o special consideration given to your personal vehicle.

They're just trying to keep their costs down, and I can understand that, but get real, how many people interested in this are going to keep their stock intake? I've seen numerous RW examples of the Stillen/JWT/K&N popcharger/intakes post real if modest gains on a dyno, and not just from the manufacturer's promo materials.

 

I think they would rather not spend (or perhaps waste) time developing flashes for mods that don't seem to work (if not hurt) decently enough to justify the time for it's own reflash.
It may not be the intake ultimately gaining hp. It could be that the intake makes the a/f ratios choppy or inconsistent thoughout the rpm/load ranges. Making tuning difficult.

It might diff if the issues were something like long tube vs short tube headers where they both gain but at diff rpm ranges. Both might need their own tune. But it could be justified because they both make gains per their specific design goals.

 

I don't think intakes per se really "make hp", either, for example the venturi popcharger and cone approach does reduce the pressure drop required to "inhale" air, but depending on how it's done, it's a wild card. I've seen widely varying results from the same intake setup, which just further reinforces the idea that it at best is an enabler for other components. It is true that some stock intakes are so restrictive adding a good WAI/CAI makes a signifcant difference, but no so with ours - the OEM is pretty good.

For example, with a K&N drop-in, it's just fine. My baseline dyno was while not overly impressive quite a bit higher than other VQ35DE's going through the same dyno, same shop. My only mod back then was a drop-in filter that I ran in my 350Z, too. At worst K&N is safe IMHO, and at best you don't have to replace it.

Very true about the A/F ratio, especially for a WAI that abandons the stock intake altogether. That's partly why I chose one that retained my stock container, keeping it a true OEM-style CAI. Most WAI's don't really stay constant through the RPM ranges, they have some impact in the midrange, fall off up top, or otherwise are just inconsistent.

However with the stillen/jwt setup, it's mostly consistent. when I look at the dyno (dynojet) there is a distinct bump around 3500 rpm, about 1k rpm's worth of ~+10 ft-lbs. It then returns close to the same as baseline power curve, then again around 4500-5500 the hp curve jumps above baseline for about ~+5 whp up to 6200 rpm. That to me shows it would be pretty hard to tune to and is probably messing with the A/F ratio in those ranges - haven't had a chance to hook up to a sensor yet and find out. I have however seen this same behavior on other VQ35DE's in 2004 V35's with same deal, a replacement tube ditching the resonator (Z's don't get) and smoothing out the intake tract. Mine is pretty typical for that approach:



Good point. For example I have a Stillen 4:1 header with long runners on another car, it consistently does what it is designed for, you can tune to that with a reflash. I can however achieve a lot better results with a RT capability with that same car on a dyno hooked up to my laptop.

I can completely empathize with any product manufacturer trying to bring the most bang for the buck and most consistent results with a wide-appeal reflash, but it seems like a big compromise. It's more my experience with seeing the results of a re-chipped or daughterboard ECU, etc, like Calum and JWT when it's tuned in place for the car with a wideband O2 sensor, etc. Otherwise I am just taking it on faith that the flash is "good" vs. customizing the ECU tune, checking the results, and again logging those results. The cost for that capability is so low today by comparison.

Recently my bud had his EJ20 tuned over at East Coast Swappers, typical Subie COBB setup. His initial COBB flash from a different shop was pretty damn good and made a lot of peak power at ~17 psi, but it felt to me like an on-off switch. Lacked linear power.

When ECS got through with it, the power was as linear as was going to get from 2500-3000 rpm up to 7000 rpm. Peak wasn't any different, but the driveability of the car was night and day. There's just no real substitute for tuning on the specific car - ECS charged him all of $300, but advanced his intial flash to the point where the car drove far better and power delivery, A/F ratios were very steady, none of the chop or big fluctuations.

 

^^ Agreed on everything you mention. Nothing like having a tune done in house. I'm hoping that Cobb can get "better" off the shelf flashes after they get more data from customers.

I would be nice if we could datalog runs on their software or Autoenginuity OBDII stuff, email them the info and have them email back a reflash. Not EXACTLY the same as an in house tune but better than a standard flash.