new chip - worth it on road car?

[Veerzigzag]

Just like to get people's opinions on re-chipping. The marketing spiel for chips is somewhat compelling: power artificially limited by Porsche to avoid embarrassing more expensive models, etc etc. At £85-odd, the ProMax chip seems like a good way to release the inner soul of my 2.7, but is it worth the effort for a road car? My car is standard apart from an, er, simplified exhaust; also it has the factory decat option. Since getting a freeflow exhaust I notice that I tend to hit the rev limiter more frequently. The plug-and-play chip change seems simple enough, but I would appreciate opinions on whether it's worth it - "if it ain't broke, don't fix it" etc.

 

[Lowtimer]

The business about being restricted so as not to embarrass models higher in the hierarchy only really applies in two cases: 944 Turbo vs 911 3.2 Carrera, and the 150 hp 924S vs the 944. For something like a 2.7 or S2, where the standard mapping is conservative it is really about tolerance for various different fuels.

Assuming your normally-aspirated 2.7 is in good order, which I'm sure it is, you won't transform it beyond recognition with a chip change, but it is likely to be a little crisper. Based on what you say about having a decat and some sort of trick exhaust, you already have slightly non-standard fuelling requirements for a perfect tune.
For that reason I think you would probably benefit more from a proper custom rolling-road remap if you can afford it. Good though the Promax chipsets are, a rolling-road remap would be tailored to your specific non-standard engine installation, and whatever grade of fuel you are prepared to commit to using in future - 97 octane, 99 octane etc. That will inevitable give you a more fully optimised map than than swapping one chipset based on a standard car for another chipset based on the same premise.

All of that said, on a normally aspirated car that's running well, and assuming you intend to keep the standard old-school air flow meter, I don't think I'd bother chipping it because the gains are inevitably very small - we're talking about just a few bhp here and there. Really to modernise a normally aspirated car completely the way forward is probably a bit more radical - get rid of the AFM for a MAF and put in a complete new stand-alone engine management system. But that is a much bigger job than you may be wanting to contemplate.

 

[Veerzigzag]

Thanks Lowtimer - that's really helpful.

 

[zcacogp]

Mike,

I know yours is a 2.7 and mine an S2, but here is a thread I wrote about fitting a chip to my car.

To answer your question in as short a manner as possible; would I go back? No.


Oli.

 

[colin944]

would be interested to see that post Oli......

can you pop a link on ?

 

[Lowtimer]

Here it is.
http://www.porscheclubgbforum.com/tm.asp?m=541717

 

[944 man]

I believe that 185bhp was a more realistic figure for the 944, but its restriction wasnt in the DME. Porsche clearly traded top end performance for through the range driveability. The cylinder head is beautiful and youd struggle to improve upon it, but the camshafts are ultra conservative and fueling and ignition timing cant make any impression on this.

 

[zcacogp]

Colin,

Sorry - I meant to put the link on my post but forgot. Thanks Simon for filling in for my stupidity!


Oli.

 

[Veerzigzag]

That link is really interesting. One comment: the "sooty plugs" - did you ever get to the bottom of that?

 

[zcacogp]

No Mike, I didn't. They are always a touch sooty (maybe sootier than I would like) and I keep on meaning to look into it.

The other problem is that my driving has changed massively since that write-up; much more town driving, much less open road driving (and a much lower mileage overall.) This will encourage sootiness.


Oli.

 

[John Sims]

There are many reasons why car manufacturers chip their cars the way they do including:-

Multiple market compatibility
Engine longevity
Fuel economy
performance
Market positioning

As has already been stated the 2.7 didn't have to fit below another model and, as such, they wouldn't have deliberately reduced the performance of a performance car as a result. This being the case, trying to increase performance with a chip alone is likely to compromise the other aspects stated above. Granted you may not need the convenience of the multiple market compatibility (but it does seem it can get quite cold and quite toasty in the UK).

Any modified chip is a "best guess" and certainly a gamble as, while it produces different results on a rolling road on a certain day, it doesn't have the thousands of miles testing that the manufacturer puts in.

Don't get me wrong, my 951 has a custom chip/induction, I ran a custom chip in my previous Freelander and am seriously considering one for my current Freelander so am not averse to chipping. You just need to appreciate they aren't magic extra power, you are doing something which could be detrimental to your vehicle.

The other thing you need to consider is insurers hate chipped cars and you will potentially limit your options on insurers and certainly increase your premiums. And you can not pretend and not tell them as, were you in a serious crash, they will check the chip. If they find an undisclosed non standard chip they could use it as an excuse to void your insurance.

Do you really want all that hassle for what may be and almost imperceptible increase in performance? You would be far better to sell the car and buy an S2.

 

[Copperman05]

On before and after dyno readings I got 10% increase in bhp and 20% in torque (S2). IMO def worth the £99 and something I would be happy to do to any 944 I purchase. Promax and JMG have sold alot of these and many are running chipped engines so I am happy they do no harm.


Edd

 

[Suffolk944]

As others have said the benefits will be relatively small but noticeable as much in smoothing out the power delivery as raising the overall power output.

Certainly have never seen a negative feedback from anyone installing the aftermarket chips supplied by the likes of JMG and Promax in normally aspirated models and the consensus is that it does improve the car/driving experience.