[ds968]

Here's a chart from a test i had done on my car about four years ago, after the BB catback and the Racer X chip install, but before the air box mod was done. I suppose another 5 + hp & some additional torque might have been added to those numbers had the airbox mod been there, but since I realize numbers themselves on any given day, or dyno, etc can vary quite a bit, the focus of my question has little or nothing to do with those, but rather, I am curious to know how the hp and torque power curves themselves, respectively, track vs. the factory power curves.

Are they pretty much parallel with the 968's published power "lines", do they deviate in any particular area, etc . ?

Again, since I did not do a before and after test, I have no clue what my numbers or power curves themselves were to begin with on my car, so no way to tell what the mods did, but vs. a standard factory model I'd like to know if the curves themselves are well aligned, or out-of-whack somewhere along the way..

For whatever it's worth, the test was done in fourth gear, and all three pulls generated near identical results ( within 0.50 both HP and torque deltas )

968dynotest.pdf Size: 93.58 KB  Downloads: 79

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[flash]

hard to tell in detail, because the one side of the graph is in speed and not rpm - math required to figure that one out

overall though, not bad, and pretty common curve shape for what you had done at the time

there is a pretty big torque dip at 57mph, which in 4th gear works out to somewhere around 3300 rpm - that is what we typically see on exhaust systems that slow the gasses down too much (open systems) - this is the dip that has caused us so much grief and cost so much time effort and money to work out

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[ds968]

<!--quoteo(post=67236:date=Feb 17 2009, 09:17 AM:name=flash)-->QUOTE (flash @ Feb 17 2009, 09:17 AM) <{POST_SNAPBACK}><!--quotec-->there is a pretty big torque dip at 57mph, which in 4th gear works out to somewhere around 3300 rpm - that is what we typically see on exhaust systems that slow the gasses down too much (open systems) - this is the dip that has caused us so much grief and cost so much time effort and money to work out<!--QuoteEnd--><!--QuoteEEnd-->

my understanding is that dip in torque is even bigger with the OEM exhaust, so whilst the "open system" exhausts may indeed reflect that same area of torque drop ( which has nothing to do with the exhaust itself ) actually have better torque than oem does in that same spot, as well as at all other rpm ranges, but it's just that they have have not managed to eliminate the dip itself.. [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]

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[flash]

nope - no dip at all with OEM

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[PorscheG96]

I'd like to propose a challenge to the both of you, since I've driven both cars and Dan's 968 is very fast. Let's do back-to-back dyno comparisons between my completely stock 968, Dan's nearly stock 968, and Bob's car w/ the entire bolt-on package so quantify the real differences here!

Any way to schedule this for the Paso day, or the day before/after???

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[flash]

not likely to happen by then - i don't see me having the time until mid summer - way too many projects between now and then - i'm scrambling as it is just to wrap those

besides, pete has already done those kinds of tests - no real point in duplicating his efforts - he has posted many of the charts too - on top of that, to be able to compare 3 cars, and get any kind of real data, would take all day - that's a chunk of change - the dyno shop i had a deal with folded up - it's not like you can just roll them in, strap them down, and get any real data you could use to compare anything

i've said this all before though - there are just way too many factors involved that would mean big differences and variances - temperature of the differential, tire size, wheel weight, tire weight, lsd vs non lsd, 12 lb vs stock flywheel, strap tension, yada yada - heck, moving the intake temp sensor 12 inches can change the readings by 10hp - same with a cold diff vs a hot one

dynos are great tools, but useless for comparing cars, unless you are going to really control the conditions, and that takes a LOT of time and care

that being said, there will be another dyno day not too far from now - sounds like fun though, and i'll be sure to let you know when it comes up

p.s. - my variocam wasn't working when you drove it, and i've since dumped that exhaust too - it will be interesting to see what you think the next time you drive it

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[PorscheG96]

Yes I've read about dyno's over the years and understand how to control the differences which should have been inferred when I addressed this challenge to you. And I don't really care what test results other folks have seen, I want to compare our 3 cars because, like I said, I think that Dan's car feels really fast for a 968. I wouldn't be surprised if his engine is more powerful than both of ours. It is a friendly challenge and I don't mind planning for this summer...you in or out?

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[flash]

well, i'm happy to try to plan for something like this, but i'm not inclined to pop for it - i've done enough of that already - the dyno work i'm planning on doing next is going to be quite enough of a burden as well - i've been spending way too much time and money on this car, and need to focus

i'm not sure which one is more powerful or not, because, as i said, mine was lacking variocam when you drove it - i just found this out when i did a blink test recently - i thought i had corrected that problem, but it turns out that it has been down without triggering a fault warning for over 2 years - i've thought my car was lacking power for quite some time, but couldn't figure it out - now i know why

that exhaust i had when you drove it, while sounding great at high rpms (albeit really loud), and even breathing nicely above 6k, was HORRIBLE on torque - it is a totally different car with the system i have now, and am making another change in the next couple of weeks (adding back in the factory cat)

i've never run them side by side with everything working to see - it turns out that even when we were at the track, i was down on power due to the lack of variocam, but, given that i have a bit higher measured compression than dan, and i already know that the rs barn chip puts out more than the racer x, as well as the header which we know makes a good amount, and i have other things done now too, that dan hasn't done yet, that i know put out even more power, i'm pretty sure i have about 12 more horsepower at peak, and quite a bit more midrange

not sure how that would equate to "which car is faster", or even which car "feels" faster, given that we all have different suspensions, and that dramatically affects how fast a car feels - the stiffer i make mine, the slower it feels - more and more it lacks the sensation of acceleration, due to a lack of attitude change - in some respects, the car was more fun when it was stock

a dyno day would be fun though, and certainly that might work out - i guess we'd have to spend a fair amount of time getting together the tools and devices to do the measuring, but i'm sure we could do it - my strap tension guage has vanished in the move, but i could get another one - i'll have the new thermometers by then, and already have the laser one

can you find a dyno with the ability to actually measure, and not just "estimate" rolling resistance and drive train loss? i haven't found another one down here yet - that will be critical - that's on my "to do" list soon too

we could also do a series of side by side runs? say 0-100 - 30-70 - stuff like that - top speed, or anything above about 100 won't really work, because i have a cab and the drag is different - but i'd be willing to do that too anyway

whatever, sounds like fun no matter what

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[ds968]

Aw shucks, thanks Trevor but what can I say.. when you're right, you're right [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]
My car is definitely torquier ( is this a valid word ? [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img] ) than any 968 I have driven, except Jeff's SC 968 of course, and pretty much everywhere at low, mid and high rpm ranges, at least as measured by butt-o-meter instrumentation, though not to a degree where I might pull away that easily...barely inching away is more like it.. However, it does start kicking a** soon as it gets to about 90mph and beyond, it's not just me having the cojones to keep it floored at triple digits because many have tried ( Sean, are you online ? ) with their speedometers above 130 mark and at that point I'm pulling away by a dozen car lengths or more..

I guess it would be an interesting challenge, though I hear the stress on the car from these dyno tests takes its toll so I'm a bit hesitant.. not opposed to the idea, just concerned about what it may do to the vehicle.. now if you guys convince me that's just myth, or the effect is so negligible unless you dyno the car every year, what the heck..it may be fun when and if time permits ..

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[flash]

lol - yeah yeah - what he said

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[RS Barn]

It's a shame you are all on West Coast. I'd love to take my MO30 coupe and put on dyno with anything. I've driven with many mods and some feel better but don't put up numbers-It gets interesting.
Just had the best ever car on dyno 246hp and 238 tq. Again we found out some tricks
Pete

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[ds968]

Another fun test, although perhaps not as accurate as a dyno, would be to get the two cars to exactly to the same weight, and then have the same driver (an independent and really skilled driver who is a track veteran ) take both or all three cars on a flat out, completely straight run from 0 to 130 ( whichever car has a better time at 130 is likely to also continue the gain beyond that mark, all the way to whatever max mph ... I’m using 130 because that can be easily and very quickly reached, a long highway on ramp will do the trick, whereas all the way to top speed would take more space and time, and thus far greater chances of being "noticed" by the local friendly highway patrol [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img] We don't want that. Or, instead of mph one could also time a 1/2 mile run, less variances like the speedo errors, influenced by tire sizes etc..

I’d definitely go for something like that before a dyno test [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]

BTW, I have to call Top Gear producers and find out is The Stig is free on May 16th ( Paso Robles meet ) [img]style_emoticons/<#EMO_DIR#>/laugh.gif[/img]

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[flash]

pete - drive it out here for paso

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[ds968]

<!--quoteo(post=67267:date=Feb 17 2009, 04:54 PM:name=RS Barn)-->QUOTE (RS Barn @ Feb 17 2009, 04:54 PM) <{POST_SNAPBACK}><!--quotec-->Just had the best ever car on dyno 246hp and 238 tq. Again we found out some tricks
Pete<!--QuoteEnd--><!--QuoteEEnd-->

[img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] wow, regardless of what variables and conditions were at play that day, unless the dyno was defective [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img] , those are some remarkable RWHP numbers for a modified but still NA 968..

that translates to roughly 283hp, but even more surprisingly 274ft/lbs ?! not at all doubting the numbers you saw, and as impressive as the hp is, I can see mods getting it there, but I can't help wonder if something was not out of whack on the torque readout ; that much force without the aid of an SC or turbo [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]

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[flash]

yup - he's doing some amazing stuff

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[DiREW0LF]

Pete, how much $$ would it take for you to tell us those "tricks" or at least how much $$$ to have you do them?

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[Fox944]

<!--quoteo(post=67326:date=Feb 18 2009, 12:24 PM:name=ds968)-->QUOTE (ds968 @ Feb 18 2009, 12:24 PM) <{POST_SNAPBACK}><!--quotec-->[img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] wow, regardless of what variables and conditions were at play that day, unless the dyno was defective [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img] , those are some remarkable RWHP numbers for a modified but still NA 968..

that translates to roughly 283hp, but even more surprisingly 274ft/lbs ?! not at all doubting the numbers you saw, and as impressive as the hp is, I can see mods getting it there, but I can't help wonder if something was not out of whack on the torque readout ; that much force without the aid of an SC or turbo [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]<!--QuoteEnd--><!--QuoteEEnd-->


Thats my car. [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img]

It has been a long road. 40 Months of ownership to get it here (i'm running 18" 993 Hollowspokes, with smaller and/or lighter wheels the car would generate even more power). There are still more things to try out and squeeze more power out of this car. I'm hoping for another 10HP. Big thanks to Pete for the Dyno Tune and all his efforts. I am really pleased with the results. Aside from a couple of modifications, most of the power mods came from Pete and the car wouldnt be making th power its making without him.

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[Ryan]

OK Fox...spill the beans. What parts have you added in order to get you to this point?

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[flash]

lol - i know and i'm not telling - neener neener

i can't get past emissions though with the stuff, so i'm stuck - boohoo - for now

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[ds968]

<!--quoteo(post=67382:date=Feb 19 2009, 08:17 AM:name=Ryan)-->QUOTE (Ryan @ Feb 19 2009, 08:17 AM) <{POST_SNAPBACK}><!--quotec-->OK Fox...spill the beans. What parts have you added in order to get you to this point?<!--QuoteEnd--><!--QuoteEEnd-->


I hear he added only one part: the new M3's V8 engine [img]style_emoticons/<#EMO_DIR#>/laugh.gif[/img]

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