Glenmhor 1

Apologies for raising this again but the retro fit S/C saga continues.

Picked the car up from OPC on Saturday and was told that the overboost has definitely been enabled. The word sport comes up on the dash when activated along with pasm and the pilot light show's on the sport button.

The only outlying issue was the fact the horizontal bar as seen in the manual showing the range from 0 ----- 0.5 ------- 1.0 shows just that, no 1.2 as it does in the manual.

Drove the car home with my daughter in the car so didn't attempt to see any overboost in the three hour drive home.

Last night went out when it got dark, temperatures down etc, to a long straight run up a moderate gradient on the outskirts of town and had multiple runs pulling from fifth gear at 2k revs WOT could not get the car to register beyond 1.0 bar boost even when I changed the readout configuration from the horizontal bar back to the standard readout (0.0).

My main concern is now this. I simply cannot feel ANY difference whatsoever between sport and non sport mode. I cannot feel the additional urgency on the throttle map and can feel absolutely no difference in pull or torque.

I had someone in the car with me monitoring the boost gauge, every pull was high gears on the incline in low temps between 2 & 4k revs and always WOT. I don't believe my car is producing the performance enhancement Porsche are advertising. Something must have gone wrong with the code input or software download.

I know people say Porsche are cute commercially but I would say from direct experience if my car is acheiving increased throttle intensity and producing an increase in torque then I could only categorise this upgrade as a blatant con.

Would some of the turbo owners out there that have factory fitted S/C please tell me honestly that if they were blindfolded and did ten high gear pulls from low revs during which five of those runs S/C was switched off that they would notice the difference immediately.

If it is honestly that obvious then I have some sort of problem.

Thanks in anticipation

Rob

Macster

In the 997 overboost is enabled by the Sport button and a fast and full depression of the gas pedal.

Overboost kicks in between 2100 and 4000, reverting back to "normal" mode between 4K and 5K rpms.

In the 997 the overboost is limited to 10 seconds and can only be reactivated as soon as engine load is relieved briefly by closing the throttle such as after a gear (up) shift.

The 10 seconds limit is due to not only the abrupt increase in mechanical loads but above all the significant increase in thermal stresses, due in particular to the continuously rising charge air temp and combustion chamber temp.

If you are doing everything right, and still not seeing overboost, it may of course be due to an installation problem.

Or it could be that overboost without say the other enhancements that go along with this feature might result in an a serious rise in intake air temp that causes the overboost to be canceled to protect the engine and the turbos from too high a temp.

Yet another factor may the quality or octane rating of the fuel you are using. While it might suffice at standard boost pressures it might not suffice at overboost pressures.

Or the altitude where you are plays a role. IIRC overboost is not supported at elevations over 5900 feet.

Sincerely,

Macster.

Shivatron

I can't say I've ever seen the overboost (or would even notice when it kicks in), but the different throttle map is certainly noticeable under all driving conditions. Throttle response is more "direct"; a good rev match takes less of a punch. Hard to think of a good "test" for it, but I would feel it blindfolded for sure.

512bb

Can absolutely tell the difference from sport to regular mode. As stated you may have an issue. Macster has basically the first points to check.

Glenmhor 1

Thanks again for your time. I think I understand the conditions required for most boost and are replicating those successfully. That is why I am using a hill and doing it at night when there is a real drop in ambient temps.

I am appliying WOT in high gears (full load situation). I'm also using 98 ron fuel. This is part of my original post re S/C as a retro fit. Porsche have told me that although my gauge would not change to show the additional range (0.2 bar boost) the car was achieving it. I struggled to understand why the guage would not accomomodate the new values but accepted the explanation given at the dealership.

The only thing is they are not used to doing this upgrade as it is rare (think it's their first) and I'm not sure it's right. When I combine this with the fact I genuinely can't notice the difference when switching between sport mode and not and factor in the car will not show above 1.0 (standard boost) I can only conclude the upgrade has failed.

Rob.

Glenmhor 1

This is what I need to hear, I have a problem for sure. I feel like a kid doing a hearing test when I used to concentrate hard to decide whether or not I was imagining things. If the extra torque is as obvious as you suggest I'm missing it.

Wife sitting beside me couldn't notice any difference either.

Thanks.

Rob

Glenmhor 1

Thanks, I wanted to feel it, the pull/ sharper response etc simply can't. Even If my electronic gauge was amended to show the additional value and then actually did achieve it in the road test I would struggle to believe it.

I have a problem. Will run out one more time tonight and try again but am not prepared to keep subjecting the car to this. Porsche need to rectify this.

Rob

Terry Adams

I waited till the end of the suggested 2500 mile from new break in period before trying it. Lots of WOT experiences before first time, and really felt it. Glad I had a straight piece of quiet road for the extra pucker factor.

Can you try some back to back runs with and without extra boost, and without the extra passenger?

jhbrennan

Another solution would be for you to get your OPC to let you drive a comparable car with the SC and let you both see and feel the difference...or find someone nearby that would tak you out in his car or let him drive yours.

aa909

Assuming the reprogramming of the ECU includes the full 1.2 bar as well as the throttle remapping then here is a simple test for you to try. Cruise at 30-40 mph in third gear and keep your throttle steady, then press the sports button, you should immediately feel a slight acceleration with the throttle in the same exact position due to the more aggressive throttle mapping under sports mode. If you don't feel this then no need to even test for boost because the sports button isn't active

now if you do feel the throttle remapping kick in then here is what I would try next. Find a stretch of road where you can go from 20 mph to 75 without much trouble. Activate the sports button and while in 2nd at 20 mph floor the throttle and on your shift to 3rd floor it again. You should 100% see a little up arrow appear next to the boost bar as well as hear an audible chime. this indicates the over boost is active. almost forgot, you should also feel the extra 50 ft-lbs of torque firmly in your seat as well

let us know how it goes
Art

Glenmhor 1

Yeah, thanks for the advice guy's. appreciate it. I have been given a good tip from a lad on the uk forum and confirmed by a reputable tuner. Fourth gear held revs steady at say 2500 rpm keep throttle constant and switch off sport button. Engine should give a noticeable "dip" or sensation of pull back.

Try tomorrow.

Rob.

phillipj

You should DEFINETLY be able to tell the difference between "Sport" and "non sport" modes. Even before my ECU tune there was an enormous difference. I seee the "overboost" graphic all the time. I have a few uphill "go fast" places that are near my home that are safe and I can get the car to 120mph or so.

I see the "overboost" graphic is all gears but First.

You have an issue. That just isn't right..

Macster

Then I would have to agree with you the upgrade failed, didn't take, or was in some way done incorrectly.

I think you are entitled to have this upgrade's presence confirmed, and its validity checked, but how that would be done (I have ideas being firmware is my job) specific to your car and its firmware I can't say.

But the dealer/shop that applied the upgrade should know.

Sincerely,

Macster.

Glenmhor 1

Update from this evening. First up thank you all for the kind advice. I did go out and replicate all the various tests I was advised to and can report this.

Of all the situations proposed the only thing I felt with confidence was when travelling along in fourth gear holding steady throttle at 2500 revs and the sport button deactivated I noticed a "lurch" from the engine. When I repeated this there is a definate drop off for all the world like lifting your foot quickly but that is all I could say I felt and this was not repeated in the way back up i.e swithching sport mode on at a constant throttle setting expecting the same lurch on the way up if that makes sense.

I cannot feel a definite difference loading the engine in 4th 5th gear from 2k revs WOT. If I let the engine run up to 3krevs and go from there in 3rd or 4th then it feels strong but not any stronger than with sport mode off.

I simply can't say with confidence I feel an instant and significant change in torque because I can't. My example last night was a fairly accurate one when I used the description of the driver blindfolded making repeated runs with the mode being activated and then deactivated randomly. In this situation I feel I would need to guess every time.

I can get the small arrow sometimews but gauge shows 1.0 bar and no audible "chime as some have suggested accompanies overboost conditions.

Over to porsche I'm afraid.

Rob.

TT Surgeon

I think it's redundant if you flash the ecu. I'd pass, had it, gimmick.