Steve -
As the resident expert here, can you explain the difference between the two chips? For example, an otherwise stock 95 6speed, Rennsport chip vs AWE.

Thanks!

 

Steve -
As the resident expert here, can you explain the difference between the two chips? For example, an otherwise stock 95 6speed, Rennsport chip vs AWE.

Thanks!

 

Hi:

LOL,.......I am certainly no expert, but I will tell you there are differences in the mapping.

There are several variations; some for race gas, some for 91 octane, some for 93-94 octane, and some for certain engine modifications.

 

So for a stock MY95 993 GIAC provides different chips for different dealers? What are the differences?

 

I made a mistake, only Tom W actually lost HP, Boris gained 2 (i'm not bothering to go back any further but there are more). I totally agree that tradeoffs can be made and that you can squeeze a little extra performance out of a stock MY95 993, just not with a generic chip.

 

"There is no difference (they are the same chip), nor are you likely to see any increase in horsepower if you dyno before & after. In fact, the last two dyno sheets posted here showed a loss of horsepower." - JasonAndreas -

He's said it well! I'll go a step further and say that without major engine mods, little
to nothing is gained.

Here's the technical basis for the above statements:

1. With the feedback element of the O2 sensor, fuel quantity is optimized for
an AFR of 14.7 which yields basically the same max torque as the AFR=12.6.
So tweaking fuel maps does little to nothing.

2. With the use of knock sensors on the 964/993, the ignition maps can be
set at max advance which was not possible in the past. As a result no real
gains occur by tweaking the ignition maps unless they're really "pushed" or
the knock sensors are disabled.

As Jason pointed out, the bottom line dyno tests are the "acid tests", i.e. "after" ~= "before".

Remember: Performance chips tweak the timing maps to get the performance "feel" which
usually results in pinging/detonation which maybe inaudible. As the temperature increases
so does the likelihood of pinging/detonation without an octane increase.

Check here ( www.systemsc.com/tests.htm ) to get an idea about how some chips
excessively "push" the timing.

Did Porsche "leave HP on the table" and/or lacked the ability to truly max the 964/993?
I don't think so.

 

I'll chime in here as I have Steve's Rennsport Systems chip in my '95. I have had it for almost 3 years now. I can't tell you about HP gains but I can tell you this chip made a noticable feel in the midrange pickup and throttle response...for my car and purpose it was well worth the price and I would do it again. I'm not trying to sell chips here...just state my opinion and what I experienced.

 

This perplexes me.
Why are we hearing about peak horsepower and torque?

 

I have to agree. Peak power is not what I would be after, more so a better mid range and flatter torque curve in efforts to help accelerate the engine given our poopy gear ratios.. My .02

 

Guys, use of my dyno data in this discussion is inappropriate. That data was for exhaust changes and not chip specific changes. If you want to compare chips, compare chips directly with dyno data and the chip as the only thing changed.

If you do a search, you'll find that a couple years ago I did a bunch of tests with a GTech ('cause I was too cheap to pay for a dyno test) where I compared 98 octane gas to 91 octane gas and the stock chip to a GIAC chip from Rennsport Systems (ie, Steve). As expected, on cool CA coastal days the gas change had no impact on 5-60 times or the hp determined by the GTech. With the chip change I saw a slight improvement in times and about 8 hp better (I did about 10 runs in each of the four possibilities).

Does that mean 100 octane is a waste of money? For 60 degree weather and driving on the street - yes. For 105+ and driving at the track - no. My data actually tells you nothing about the track and hot days with a hot engine. That would be a different set of tests. Likewise testing a chip biased for racing and high octane gas under the conditions I used would be a waste of effort and tell you nothing of value.

My point is to remember that you must check the conditions the test was performed under and draw the conclusions appropriate. (I'm a scientist, it's my job to always remember this stufff and remind others when they draw the wrong conclusions. )

 

Thanks, everyone's input has been very interesting. However, I think we should stick to the question at hand, which is the difference between the most popular chip (for rennlist members) which is the rennsport chip, and the AWE chip which is also GIAC. Can anyone definitively tell us what is the difference between the two chips? I'm talking the "off the shelf" versions, not custom programmed race chips, or chips for LWF, etc...

According to AWE, their chip is tuned for 92 octane fuel...

 

Boy, first thread i read in a while (i've been way too busy) and i noticed my name. So i thought i'd chime in..

1. It is true that the rennsport chip did NOT produce a significant amount of power over stock. (I do think my test was a fair test).

2. It did smooth out the power curve of my car. This is especially important for a '95 (meaning no varioram). It is noticeable and worthwhile. And you can go back to my previous post and graphically see what i'm referencing.

3. i'm not sure a dyno is the best test to determine the benefits of a chip. why you might ask... well for a number of reasons. Peak HP is not everything (yes i said it). Also dyno tests only measure WOT response. a large improvement in driveability that can be gained from chips (like rennsport/giac...) and these are difficult to reflect in dyno tests.

i do not know if there is a difference between rennsport and giac chips. i can tell you mine came from steve but has a giac sticker on it. i'm not going to draw any conclusions from that.

also i'm not sure that i buy the argument of chips not being able to improve performance. not only for the partial throttle response argument, but i'll simply state that since '95 engine management has evolved significantly. just look at the newer m3's and you'll note that they get 100 HP/liter. Their displacement is not increasing just power and the experts i've spoken to suggest that some of those gains are through engine management. It may very well be true that with a sophisticated engine management system 993's could see significant & reliable HP increases. It may also be very true that the brain would need to be replaced as the stock one is too primitive to obtain such results. My point is we just don't know until someone produces a product here.... i know there are some in the works...

cheers,
boris

 

Boris, please don't leave us hanging here - if there are "some in the works," can you elaborate a little? haha

I've read online about Ninemeister over in Great Britain achieving some pretty impressive gains using Motec with the 3.6 motors...

Thanks for any info!

 

Any EFI system is a means to an end, i.e. It can help achieve the max from an engine design.
It's the mechanical system design that's the key. Once a new element is designed-in,
e.g. the VarioRam, the EFI system can maximize it's contribution. Without a modified/new
mechanical technology, EFI tweaking generally yields little over a well-designed EFI system,
e.g. Porsche/Bosch Motronic.

Initial electronic systems allowed the point ignition & carb type engine to achieve more ideal
efficiency, i.e. enhanced thermo-dynamics, and performance, but without new mechanical
technology, the overall system reaches a limit. And this is case when adding a performance chip
to a well optimized EFI system such as the Porsche/Bosch Motronic.

Systems such as Motec can achieve some performance gains for specific applications
such as racing, but really just provides much more flexibility in tweaking for the end application
and not significant overall performance enhancement, given a non-racing mode of operation.
This further exemplifies that the mechanical system design is the key, and that the electronics are
only the means to the end.

Bottom line:

It's the electronics system design that's the easy part of the "equation", given the availability
now of the microprocessor and programming languages, e.g. an F1 engine & electronics.
Nothing really that state-of-the-art in the electronics of an F1 car versus the latest Motronic.
If there were a difference, a basically simple change of a map or micro-code eliminates the
difference. So, in the end, tweaking a well designed system via a performance chip becomes
a big "?", as the well-designed system is already "there".

 

Just a note on 'improved throttle response'....I have read this time and time again but don't understand what it means....how do people notice this? Even when my car was stock (and now it is far from it) I would press the throttle and the car would respond. I don't know whether it took say 7milliseconds when stock and say 5millisecond after mods for the throttle to 'respond'....what does it mean....? I have LWF in mine amongst other things and of course the car revs much quicker out of gear...but the throttle response thing when driving...what IS that?