[earossi]

I have monitored this site and 968.net for a few months and have kept up with all the powertrain modifications that have been discussed including, exhaust systems, chips, air box modifications, etc. Has anyone who has made some or all of these modifications been able to quantify the impact of any increased performance? Most posters talk about "seat of the pants" feel, but what I would be interested in knowing about is any inproved acceleration. The stock 968 is supposed to hit a 0 to 60 time of between 6 and 7 seconds. Has anyone done any testing that shows a marked improvement on the stock numbers? And, if so, are you able to match up acceleration numbers attributable to each modification?



I'll be working on my car in the Spring (to cold in Chicago to work on it now), and have a limited budget, so am interested in what the biggest bang for the buck is that I can do in my own garage. At this time, I would like to limit any mods to bolt-ons or minor mods that do not require an engine teardown.

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[flash]

i haven't gone out and done runs now that i have the last couple of mods in, but before, when i only had the racer x chip, a larger snorkel, and the flywheel, i did some inmy cab - my WORST run of the day on that day was 5.65 - i don't want to post my best run, because there are some who won't believe it



now, i have better hookup, dave's and my intake mod, more fuel pressure, and the power pulleys, as well as 250lbs less weight



i'll be doing more runs soon - i'll take a video camera with me this time so i can document the run

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[earossi]

Flash,



Do you have a feel for which of the mods produced the greatest benefit? To have taken over a seond off the factory numbers is amazing. Please keep the board posted when you are able to document your times with all the mods in place. Incidentally, did you ever put together the exhaust system you had mentioned several months ago?



Regards,



Ernie





[quote name='flash' date='Jan 3 2006, 10:14 AM']i haven't gone out and done runs now that i have the last couple of mods in, but before, when i only had the racer x chip, a larger snorkel, and the flywheel, i did some inmy cab - my WORST run of  the day on that day was 5.65 - i don't want to post my best run, because there are some who won't believe it



now, i have better hookup, dave's and my intake mod, more fuel pressure, and the power pulleys, as well as 250lbs less weight



i'll be doing more runs soon - i'll take a video camera with me this time so i can document the run

[right][post="14045"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

the modifications, and how they improved 0-60 times, are listed as follows, in order of my percieved effect, largest first:



flywheel (close to .5 sec on this alone)

weight reduction

lsd

racer x chip

intake mod

larger tires, lighter wheels, and new suspension to match

power pulleys

adjustable fuel pressure regulator

ngk iridium plugs



now, keep in mind that i am taking this car to the new redline and slamming the shift to second - this is not possible in a stock car - in doing its job of smoothing thigns out, the DMF will prevent any such rapid shifting



as with anything, there are ups and downs to these mods

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[BruceWard]

Could you elaborate on "slamming the shift to second - this is not possible in a stock car"?

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[flash]

i could, but since it's you that asked..............



this has been discussed at length before

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[ds968]

[quote name='earossi' date='Jan 2 2006, 06:57 PM']The stock 968 is supposed to hit a 0 to 60 time of between 6 and 7 seconds.  [right][post="14035"]<{POST_SNAPBACK}>[/post][/right][/quote]



For the cab ?! Because the stock coupe's tested 0-60 results performed and published by various car magazines ranged from a low of 5.6 to a high of 6.2



I have no clue what my car with the three mods ( chip, air, exhaust ) does 0-60, nor do I really care since I have no interest in blasting off from stop lights, but I can tell you that on the highway I am consistently outrunning ( marginally, but

nonetheless a few feet ahead..) cars with posted Q-mile stats around 13.5 sec...

one in the 13.2 category, but I think that might have been just a fluke ..



In any event, I'm guessing these mods plus the modest weight reduction from the exhaust and spare tire shaved at least one second of the 1/4 mi time, if not more.

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[S_Cal968]

I'll have to do a search on slam shifting because it would be interesting to see what the net gain is with a lighter f/w.

Obviously the dynamics are different between the 2 f/w's. The lighter unit will spin-up faster, but will be more adversely affected when a load is quickly applied (as opposed to a heavier f/w). [just a thought...]

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[Etnier]

[quote name='flash']the modifications, and how they improved 0-60 times, are listed as follows, in order of my percieved effect, largest first:



flywheel (close to .5 sec on this alone)

weight reduction

lsd

racer x chip

intake mod

larger tires, lighter wheels, and new suspension to match

power pulleys

adjustable fuel pressure regulator

ngk iridium plugs[/quote]



It's worth bearing in mind that the chip and intake mod are very easy to accomplish: my guess is that if you combined them into one item it would move up that list several places. In my case I chipped the car and was really impressed with the performance gain. The airbox mod followed (I was already on K&N filtering) and another substanial boost came with that.

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[flash]

i've driven cars now with only a chip and airbox mod, and a couple with also an exhaust



flywheel is good for about double the difference of those mods - the math works out to an equivalent of 39.4hp in first gear (i didn't do that math - somebody else did about a year ago, but it feels about right)



shifting speed increase of a single mass over a dual mass is good for every bit of a half a tenth all by itself, even if the flywheels weighed the same



yes, if i were to combine them, they would move up, but not above the flywheel, and would be about a tie with the weight reduction

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[BruceWard]

[quote name='flash']slamming the shift to second - this is not possible in a stock car[/quote]



........



[quote name='flash' date='Jan 3 2006, 03:21 PM']i could, but since it's you that asked..............



this has been discussed at length before

[right][post="14073"]<{POST_SNAPBACK}>[/post][/right][/quote]



I have never had any problem chirping the 265s on the back of my 968 shifting form first to second. Chirping from second to third is a little more of a challenge.

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[flash]

neither have i with my 285s - third is also not a problem



that, however, is not my point, and since you want me to, as you so eloquently put it, "refrain from educating you" because you "find bliss in lacking my knowledge", i am not inclined to explain it to you

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[ds968]

[quote name='BruceWard' date='Jan 3 2006, 05:23 PM']I have never had any problem chirping the 265s on the back of my 968 shifting form first to second.  Chirping from second to third is  a little more of a challenge.

[right][post="14084"]<{POST_SNAPBACK}>[/post][/right][/quote]



Damn, you guys are making me take the car out now just to see if I can get any squeak out of my 265s slam shifting from second to third - I doubt it though. Agree that first to second is a piece of cake.

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[flash]

i've had the first/second shift spin so hard it launched the car sideways - i usually get a really good scratch there, and a fair bark going to third - i barely touch the clutch, shift as fast as i can move the shortened shifter, and BANG! down goes the rubber



i haven't run the 1/4 mile yet, but i will when i go out to run the 0-60 times again - the flywheel becomes less of a factor as you go up through the gears, so i am not sure where i will end up



things really come together up at about 7500, though i'm not inclined to do that very often, or they might also come apart

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[Andre]

Flash,



I searched autozone for iridium spark plugs and I got Denso parts described below. Do you use different ones (you mentioned ngk) and if so, where did you get them and what part numbers work for 968?



DENSO SPARK PLUG for a 1994 PORSCHE 968

Unit Price: $12.99

Part No.: 5307#4

Weight: 0.15 lbs.



Regarding the racer X chip. I have a Welmeister chip now - is performance gain big enough to swap it for the racer X? I know that you did the chip comparison before, but my back ordered 9 Magazine never arrived (is there a link to this article someplace or anyone has an extra copy?).



Thanks,



Andre

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[flash]

www.sparkplugs.com



on the chip, only if you are running a lot at the top end of the rpm range, or if you are racing, would you find the additional power worth the money to change - there, any little bit you can get helps - on the street, it's not worth changing



you never got your issue? was it to be pdf or hard copy?



anyway, if you go to www.9magazine.com, and go to the DIY section, under 968, the article is there for free

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[bob blackwell]

CAUTION! "Slam shifting" may be fun but it is very expensive. I had to have my transmission rebuilt on my 924S and the Technician showed me the results of my shifting technique upon the first and second gear synchros. Recently I had to have the transmission rebuilt on my 968 when the pinion bearing started to whine and ended up replacing the first gear synchros again.....I think I have finally learned how to properly shift gears in my Porsche. Pause just a heartbeat between gears and you will have a longer life transmission and save a couple of thousand dollars. Good luck, Bob Blackwell.

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[flash]

agreed - this is not for the faint of heart or the light of wallet, and do NOT do this on a DMF! bad things happen



i expect to rebuild my box every 2 years, so i am not worried

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[Cloud9...68]

[quote name='bob blackwell' date='Jan 4 2006, 05:47 PM']Pause just a heartbeat between gears and you will have a longer life transmission and save a couple of thousand dollars.  Good luck, Bob Blackwell.

[right][post="14133"]<{POST_SNAPBACK}>[/post][/right][/quote]



This has continued to perplex me. I have always used the "pause a heartbeat between gears" technique on every other car I have owned, but when I first picked up the 968, I found that doing this resulted in very rough shifts, because the revs drop so fast between shifts on this car, that pausing, even for a split second, between shifts caused the revs to be WELL below the value needed at the completion of the shift to the next higher gear. This doesn't makes sense, given the heavy dual mass flywheel. The only way I can shift it smoothly is by performing the shift very fast; the faster I move the lever, the smoother the shift. Thank goodness I have a short shift kit.



Has anybody else experienced this? It's never bothered me, because I don't mind being "forced" to shift fast, but now I'm getting worried, based on Bob's post, that it may shorten the life of my transaxle. But since fast shifts = smooth shifts, it doesn't seem that shifting fast should hurt anything. I always depress the clutch fully (and double clutch on downshifts; my goal is always to have the revs be at the proper value upon completion of the shift, whether an upshift or a downshift).



The way my revs drop between shifts, I'd swear I have an aluminum (or paper mache...) flywheel, though I don't have any of the other symptoms. I'd be glad to start a new thread on this if there is enough interest, as I'm very curious as to other peoples' experience with how their cars shift...

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[flash]

give me a call - i'd love to figure out if you have one too - if you lost my number, drop me an email



it sounds like it by the shifting and rev thing



the pause we are talking about, to prevent damage is less than a second - the shift i am talking about for best 0-60 is almost instantaneous - i can't even click my stopwatch that fast - there is no time for clutch action, and you barely touch the pedal

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