ksose

Hi to everyone;
i apologize for my english and i hope to explain correctly my problem cause i need help.

i'v a 993 my 96 (varioram) and i can't find a solution for this problem:
only in 6 gear my car doesn't reach high rpm.
in 4 gear it's reach 6,800
in 5 gear reachs 6,800 (230 kmh)
in every gear at 6,000 i feel a thrust (to 6,800)
in 6 gear stops at 5,800 (250 kmh) as a wall
only one time (with very difficult) it passed the "wall" and at 6,000 the car started to push again as there were no problem

my mechanic checked the chip; the varioram (totally cleaned and checked it as read in this forum), the fuel pump, the cable and everything it's ok.
it doesn't smoke and oil consumption is ok.

i've a suspect but it should be incredible...the spoiler has the black plastic bulkhead broken in the middle...it's possible than at high speed it can't convey air to the engine?

ps: the 993 has the G64/21 with LWF, BMC filter
thanks

Ksose.

luv2ride

Hey ksose!

where on earth can you drive at that speed to notice that in 6th gear your not able to redline? WOW! in my neck of the woods thats a death sentance. To many cars on the road and too many cops.

ksose

Hi luv2ride,
i'm italian;
i can run very fast only on track during the trackdays (in monza you can reach the red line in 6th) .
sometimes it'is possible but dangerous on some freeway that we know, with few cars and where there are no cops (thanks to low traffic).
but our limit is 130 kmh and up than 170 kmh we loose driving license if they catch us.
can you help me about the problem?

thanks

leosayer

At that speed, you're pretty close to the tob speed of your car (275kmh IIRC) and most of the power is used to overcome air resistance.

I would be more worried about the spoiler wall breaking off and losing downforce at those speeds. Get it fixed before trying it again!

ksose

leosayer the spoiler move up so the car doesn't loose the downforce.
i have found a picture on the net where you can see the black plastic wall;
mine it's broken...once a mechanic told me that this component convey air to the engine

http://www.plumley.org/porsche/photo...all_raised.jpg

tomorrow i can upload a picture of mine

bye

kdurg

Check the seating of the BMC air filter in the airbox. These aftermarket air filters have been known to either crimp or block the air flow into the MAF. Although I think you'd be having a problem in each gear, not just 6th if this was the cause. Worth a look/see. Good Luck !

Robin 993DX

I think you are fighting the wind resistance at that speed not that it is not moving, just that it is moving very slowly....

Or maybe in Italy the Govornment required Porsche to put in a limiter on how fast you can go? Maybe try a DME from a US car?

ksose

probably but it moves too slowly compared to other 993.
i can't reach the declared maximum speed ...there is something not working (i thought about vram failure cause at 5,800 it opens the valve but isn't it...it works fine)

no, i'm sure;

now i'm going to change the spoiler wall;
perhaps replacing air filter and air box with a PowerFlow-Kit could be a solution? but i'm only tryng cause i don't have any idea

the problem is that i can test the car only on the right track so i can't have an immediate response.

ZombiePorsche44

The spoiler wall has no bearing on RPM or airflow to the engine, all it does is cancel lift at the rear end of the car at high speeds.

I can tell you from experience that I could not get my 993 to 6800rpm in 6th either because I was going 160mph at around 6000rpm and figured it was time to back off before I killed myself.

ZP44

chris walrod

vMax in the 993 is in 5th gear -- the car doesnt have enough torque to push the car in 6th. I feel aero drag is the reason you cannot redline in 6th.

ksose

mhm...
two considerations
my 993 (model year 96 but october 95 construction) has the the g64/21 transmission with short gear; the /20 with long gear was introduced in italy in 1996 only (i don't have information about other countries); by the way i reach the maximum power al 6,600 rpm (i'll seek the article with power and torque diagrams comparison between the two transmissions that explained me these differences)

moreover one time i exceeded 5,800 rpm in 6th gear (after some kilometers with rpm gauge indicator fixed at 5,800) and i felt a kick at 6,000; i can imagine that the car was reaching top speed (i hope.... cause i had to slow down)
after this event i started thinking about a problem

leosayer

Not true with the gearing in my car, v-max in 5th is around 150mph, I changed up to 6th and got 158 before I had to back off.

Peter B

I hope you were wearing your Assistant Chief Deputy Constable Detective Police Commissionaire uniform when you was doing this here rate of knots, Sir?
If you was you will only get 42 days ban and an MBE and probably a Knighthood when you retire

Peter B

Oops, missed the gold plated pension as well!

911C2

With all due respect, Redline in 5th is 150, shift to 6th and she kept going at 155 she was still accelerating not like 1st or second but still going. I backed out.
Helmet on.