blue44

hi, I read a bunch of old threads about the airbox mod over the weekend, right now thinking I'll pick up a used airbox to drill, what do you think ? and which chip would you recommend for a stock engine, RS Barn or Promax ? planning a few DE's but mostly my reverse commute these days...
thanks,
Donn C.

SpeedBump

Either chip will make your car more responsive. There are happy proponents of both chips here, I have two cars with different RSBarn chips and am quite happy. Raj, Damien and several others are happy with the ProMax.
Just make sure your car is in good shape before you do the chip

PorscheDude1

+1 on RS Barn chip.

Also if you do more engine mods, RSB has a free trade in to reflash the chip.

As far as I know the other chip vendors do not offer this.

RajDatta

I found the Promax chip to offer the most torque in the mid range. I drove cars with other chips and that was the one difference I felt. The Promax chips really makes the car come alive in the midrange where most of us do our driving.
Dave Greimann, the originator of the Airbox mod also uses the Promax chip and he had the same feelings about the chip. He felt that it gave him the most torque in the mid range.
Raj

Damian in NJ

Until I get my car dyno tuned I'm very happy with my Promax chip. It works very well with my mods.

968workaholic

Seat of the pants isn't an accurate gauge for which chip is better than the next. Dyno charts are the only real measurement of which chip is better than the other. The trade in program that RS Barn offers isn't a free trade, but the cost of the Stage 2 chip is $100 cheaper if you have already bought a Stage 1 chip and trade it in. There are only so many things that can be changed on a chip to improve power and torque. The question is which way do they progam the chip to get the power? There is a trade off for programing one way versus the other.

RajDatta

No one ever claimed seat of the pants is an accurate guage but that is what we are all looking for, seat of the pants improvement. A 5 hp improvement up top does little for me if I can't feel it in the mid range, which is where I do 90% of my driving.
Some chip companies tune using aggressive iginition timing and others use fuel maps and some use both. If the timing is too aggressive, you have the potential of blowing your engine up. Its happened before.
Also, as far as independent dyno test, hopefully we will get some one of these days.
I plan to have another dyno day soon and maybe someone can join us with each of the chips in question. It will be an independent test for everyone to see how each chip performs.
Raj .

rpm's S2

That would be a great test if you can control for other mods and the relative engine condition on the individual cars. It has been a while since we had any data on chips and most have probably been subtley tweaked by the different vendors in the intervening period. I'd be very interested in the outcome.

RajDatta

My car is bone stock. The dme is still factory sealed so it will be as stock as possible. Since I am doing all this work to the engine, I was planning on doing another baseline anyway so I would be happy to volunteer. Before I took it apart, it was in excelklent health with solid numbers.
I will let everyone know when we can do another dyno day.
Raj

earossi

If you take a look at postings on the 968 Forum site, you will find that there has been quite a bit of dyno testing done with the various chips out there. RS Barn ran some controlled tests on a dyno while changing out chips from various suppliers. So, much of that work has been done already. Just search the Forum site to find the postings.

I personally am running the RS Barns Stage 1 chip with the air box mods. I talked to the owner of Barnes, and asked his advice, and he advised using only the Stage 1 chip with the air box mods and the Barns exhaust that I have on my cab. Which is what I did. To move up to the more aggressive Stage 2 chip, he advised installing their headers.

As mentioned above, I think there are several chips out there that will all make a noticeable improvement to our cars. But, the biggest improvement I saw was that the car seems to be easier to drive, and it appears to be smoother in transitioning. I think they call that driveability. Though it is rather subjective, I can tell you that it made my car more fun to drive.

The biggest step change in power, for me, was doing the air box mod. There have been various claims that you pick up 5 to 10 hp from this mod, but it is definitely noticeable. And, the mod is cheap.

Just my two cents.

Ernie

RajDatta

Ernie, I am talking about independent dyno tests here. A vendor doing a dyno test where their chip outperforms other chips is nothing new. I am sure every chip builder would get the same result.
Raj

odb812

as i remember, a guy who's name i won't mention did all these dyno tests and the difference between the rsbarn and promax was very minor. like the performance difference between the two was about the difference you'd see with a few rand mcnallys sitting behind your seat. if you aren't planning on upgrading headers or cams or anything significant which would require a different tune in the future, i would suggest saying the two names out loud three times and deciding which one you like better. there is no need to get into another one of these big debates over this. a lot of very knowledgable people like the one and a lot of very knowledgable people like the other. at least you guys don't have the early dme and are stuck with the autothority like i am.

SpeedBump

Well said Todd.

RajDatta

Todd, I agree whole heartedly and wasn't going to bring up any dyno charts until others brought it up.
That is when I offered an independent test.
This subject has been discussed a million times and we will always agree to disagree. Each side has its supporters. Bottomline is, you can't go wrong with either chip.
Raj

Jfrahm

One chip test I read was pretty bogus. The guy was getting the stock crank HP to display on an old G-tech, then testing from there. I assume this was done by playing with the vehicle weight until the G-tech read what he wanted it to read. G-techs generally read pretty low as they show you 'net' HP after driveline loss, aerodynamic drag, rolling resistance, etc. If indeed he'd goofed with the G-tech to read 25% or more higher than expected, the delta between the stock and aftermarket chips would also be inflated.

That being said I think it might be that the benefits one gets from a chip would be found in the midrange as well as perhaps a fer HP up top. I think a fair test would be to have a chip or chips swapped into and out of a car while it's driven around the mountains over the course of an afternoon. The drivers take notes without knowing if they are running chipped or not, and the data compared later, perhaps over a beverage and snacks. This would be pretty easy for me to do as I have a 968, the mountains are right over there, I can get another driver/chip swapper and I know a few places that have decent wings. :-)

As for the airbox mod, I think it's silly so it's wise to cut up a spare airbox. Don't drill 'speed holes' in the only airbox you have.

-Joel.