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Gutted my cat. a little odd
#41

when i talked to B&B they told me the 968 chart was a misprint, and that it was actually a 944, and that they had never actually tested on a 968, and had no charts for a 968.



your chart shows peak power at about 6600, which is a bit low, but could be due to a few things. fuel cutout on your chart shows a redline at about 7400 rather than 7800 like it should be, which is about the same relative amount of drop in rpm. i suspect it is a calibration thing, since your chart is showing speed and not rpm. likely he did not calibrate your tachometer to his speedometer.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#42

Yeah, I don't remember him calibrating anything like that..

On BB there could also be some miscommunication at play, and depends I suppose with whom one speaks. I talked to Billy Boat himelf as well as Mike Ryan, and have e-mails from them as well - what they told me is that they did not to a test on a 968 AT THEIR FACILITY, but rather at an independent dyno shop someplace in Arizona,( where it was is listed on the results sheet..) . He said the 944s is provided along with the 968 test for reference ( I also thought it was a misprint given the low stock rwhp readings ) but Mike said it was a 968'just one with obviously a lousy engine.
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#43

i have those charts here too, if i can just find them.



based on what i remember from that chart though, if it were that bad, it would have been smoking like a freight train. the curve is all wrong too. i am pretty sure it was from a 944, and just a misprint. that is also what they told me when i called about this the last time we went round and round about this.



i really am quite certain that it is doing exactly what it should. it makes a couple of hp up top, and loses 20ft/lbs or so over about a 400rpm range centered at about 3400, just like every other "free-flow" system. the lack of resistance makes it feel snappier, but isn't really making more power. this is very deceiving. that doesn't mean that the car wouldn't be faster though. quicker revving equates to faster acceleration. it's the same thing with a light flywheel. there isn't any more power, but the decrease in resistance means it revs faster.



in the end, the numbers really don't mean anything if you don't spend any time in that range, or if the other benefits outweigh the losses. i gave up a little top end with mine, in order to gain back low end. it's always a trade-off. there is no free lunch.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#44

It made 170 rwhp (stock) which seemed rather low to me and that's why I asked them if it was a misprint and if they had used the 944 chart.. They categorically stated that it was no misprint, it was a 968 which was tested , just with an engine that was perhaps as much as 20% below what a newer 968 engine would produce. No, not a " couple of horsepower " , the 2 and 4 hp gains were at low end, the chart shows mostly 10 , 11 and 12 hp gains at the upper ranges , above 5000 rpm, and BB said on a strong 968 engine , unlike the one they tested, that would without question translate to 17 to 20 hp, with near double digits hp and proportional torque at every other spot above 3500 rpm

They did mention the torque dip at the lower rpm level but indicated it was no more than 3 or 4 ft/lbs drop and ONLY in that 400 rpm band. Otherwise there were significant increases everywhere else.

Look, as I said, charts are charts and anyone can poke holes in their credibility. And I'm sure whatever BB claims reflected in those PDFs I'll try to upload next week will be subject to much scrutiny, and refute, but all I can tell you is that if you put up a 968 of equivalent weight to mine, one that has a chip and air box mod, but stil has a the stock exhaust, you can use any start point you want, in any same gear, at any same rpm range, and I will outrun it, not by a nose, but by car lengths ( done that many times, with many forum members witness to that ) and the ONLY explanation at that point HAS TO BE at least a 15 - 20 hp and torque delta produced by the BB catback... because there is nothing else to attribute it to. Or may be there is, but I can't think of what else it may be. I am a fairly poor "race"driver by comparison to some of you guys, so it will definitely not be driver capabilities that factor in to my advantage, in fact, probably just the opposite.
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#45

i just spoke to them. they are going to double check, but they are pretty sure they never tested on a 968, and were just applying things from a 944, because it fit the same. they did say for sure that they would not have done much testing in any case. i should hear back later today to verify.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#46

Hi guys i had the pipe welded into the cat today the car feels great, the remaining cat back system has remained standard i am very happy and pleased with the results.

thanks for all the info on this thread although my head is spinning................!!

cheers
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#47

Dan,



Do you still have your old exhaust? Or might there be someone in your area who still has theirs after having removed it in favor of an aftermarket cat back? If so, I think the only way to settle this would be to do an "after and before" test on your car on a dyno, first with the BB, and then with a stock exhaust placed back on. Definitely a lot of hassle and expense, but I don't see any other way to quantitatively demonstrate one way or the other the capabilities of the BB.
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#48

I still have the oem catback, but no way, no how, I'm ever going through the hassle of switching things back and forth again just to do a dyno test, and on top of that subjecting my car to unnecessary stress ; this issue is not nearly significant enough ( certainly not to me ) to warrant doing that. I don't have a need to prove anything to myself or others on this topic, I simply posted my personal experience with the BB in my car, and what what their assertions re performance on the cars they tested were. However, in the meantime, I talked to Flash and learned there are so many other things which work in combination with one another that influence power and torque, in ostensibly identical cars, that you can't conclusively / absolutely point to one single factor you think is THE one that makes all of the difference. Bob can explain that better, so I'll defer to him to chime in on that.

Nonetheless I think that BB test results need to be further explored and explained for those that consider going to a tri-flow catback on their 968, because in combination with everything else that goes on with their respective engines they either may stand to gain from switching, or that there is also a distinct possibility there will be not much to gain but the sound. Again, more so than ever : YMMV !

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#49

lol - I finally googled YMMV - Your Mileage May Vary. I'm probably the last person on earth that didn't know that. Then again, I'm probably the only person in the western hemisphere who doesn't own an ipod (or an ipad, an iphone, or an i-anything).



Anyway, given the passion of this discussion, I thought there may be a chance you'd be willing to do a comparison with the different exhausts, but I fully understand why you wouldn't want to - I wouldn't, either.
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#50

No iThings ?! That's even more controversial than anything on this thread ;-) , lol.
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#51

And it's not like I'm a fanatical Windows/Android person who owns the non-Apple equivalents of all of these products - I simply don't own nothin'. I'm actually the sole supporter of a wife and two teenage daughters who's so broke, I can't even pay attention... <img src="/forum/images/smilies/968/ohmy.png" class="smilie" alt="" />
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#52

lol - i barely use my cell phone, which is an iphone (albeit a 3 and not even a 3S). i am likely one of the last ones on the planet who thinks that a cell phone is just for emergencies, and is the rudest thing to use in public. when and why did we become so dependent on instant access? is that really a good thing?



i don't want or need to be so accessible, and do not want to be interrupted with a phone call. i don't text, and feel that texting is the downfall of the written word. people can send me an email, or leave me a voicemail. i'll get back to them when i can devote my full attention to them, which is the only decent and civilized thing to do. nothing annoys me more than being in a meeting with somebody, who then gets a text or phone call, and has to stop what we are doing to deal with it. i have gotten up and left when that happens. i will ALWAYS immediately eliminate anybody who does that from any bidding process when i am looking to hire somebody. i blew 2 of them out the door last week.



remember when we had rotary dial phones, no answering machines, no call waiting, and no email? people actually talked to one another face to face. no flame wars. no miscommunication. no internet bullies. what a concept.



back on topic now.



there are indeed a number of things that can easily explain why dan's car might be faster than another car. the least of which is the balance of the engine and the setting of the cams. the cams alone can make as much as a 20hp difference. the state of balance can easily mean 1/4 second off your 0-60 times. the same goes for intake casting variance, valve condition, lifter condition, etcetera. all of these things add up.



engines are built to within certain tolerances. these tolerances leave a lot of room for variance between engines. if you got one that was perfectly balanced, and the cams were set to one direction, you could have an engine that made more power up top. if the cams were set to the other direction, it would be torquier down low.



this is exactly why engine builders and tuners get paid so much. they know how to take advantage of these things, and get the most out of an engine, without changing it from stock. this allows them to get the most power without breaking any rules. it really is a large difference.



basically there is enough variance between engines to easily equal anything you could bolt onto it to make more power. so, for example you could even have a car with an engine at the lower end of the scale, with all the bolt-ons, still get outrun by a car with an engine with no bolt-ons but at the upper end of the scale. if you were lucky enough to get one at the upper end of the scale, and then bolt things on, you would really have a nice setup.



this is likely where dan is. lucky guy.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#53

Amen Bob! I work for a large Telco and I abhore texting and cell call interuptions. Probably because both my kids (18 and 24) can't unglue them from their face. Now where's my rotary dial phone again?
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Dave



'93 968SC Nachtblau Metallic Coupe

'89 944 S2 Zermatt Silber Sold

'87 944 Silber Rose in colour only Sad Sold
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#54

I for one was absolutely stunned to hear that; a minor thing like cam timing can account for as much as a 20 hp difference just by itself !! So if you have a combination of things going on in your favor, that "perfect storm" might put your car in a completely different league vs. one which has a reverse perfect storm at play..



Well, I don't know about the "lucky me " part of this, I suspect half of the 968s out there are just as well balanced and as fast...with comparable mods..



Nonetheless, I still want to get to the bottom of the BB thing, ,so others can form their own conclusions in case they're considering that option, so I'll put up what I have from them on Monday..and " let the games begin " It will be interesting to see how they respond to Jay and to Bob, because I also found the email from them which backsup what they told me on the phone.. but there are some very interesting rpm ranges ( anything below 3500 ) missing from the 968 test, whereas the944s test has every 250rpm increment from 2000 on up...so I have to wonder why That is, as well as how well that 968 could have possibly been running with a 160 or 170 rwhp reading.
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#55

so here are the papers BB provided ; I "inserted" the email wherein they confirmed that the test was done on a 968 so it was not a misprint which used 944s data, but the results still leave some open questions, nonetheless.. maybe Greenway Ato Service where the dyno

was done has more specific charts for the 968 including the torque results. In phone discussions Mike , he said the torque gains were similar to the 944s ( that's why they provided the 944s sheet with the 968 system info ) and the HP and torque gains on a well balanced 968 engine would be 15-20% higher than what this particular test shows ..
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#56

Flash is right that miniscule engine build variences can make a significant difference in the final power output of the engine. I encountered this back in the 90's when I attempted to chip my '95 M3. The first chip I tried (this was from Jim Conforti, probably one of the most respected BMW tuners outside of Steve Dinan) caused detonation at full throttle, so I returned it and Conforti then sent me a 'high compression' chip that was supposed to be mapped for M3 engines that ended up with slightly higher compression. This chip also did not work.



Jim suspected that my car might have ended up with one of the higher output engines that were hand-picked off the assembly line for use in the E36 M3 Lightweight. These engines were not different in any way, but for some reason they just happened to put out 10 or 15 extra hp. Had to be the balance.



After I sold that car (to the father of the guy who owns EvoSport, a BMW tuning outfit), I learned that the only chip that would work in it was one that they had to have Jim custom tune on a dyno.
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-Austin



'94 Black/Tan Coupe

6sp. LSD, 18" Carrera Lightweights, M030 struts and sways, Racer-X chip, airbox mod
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#57

I have not receibved a response from B & B...will keep you updated....



Meanwhile I'm battling with Garmin because their "Lifetime Updater" software turn my Nuvi into a paperweight.....<img src="/forum/images/smilies/968/sad.png" class="smilie" alt="" />



Jay
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“Faster, Faster, until the thrill of speed overcomes the fear of death.” - Hunter S. Thompson

"I couldn't find the sports car of my dreams, so I built it myself." ~Dr. Ferdinand Porsche

"968Forums, a quaint little drinking community with a serious horsepower problem"

"Life's journey is not to arrive at the grave safely in a well-preserved body, but rather to skid in sideways, totally worn-out, shouting, 'Holy sh*t! What a ride!'"- Unknown
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#58

i haven't heard form them either, which to me says "busted"
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#59

or, they just don't give a crap about whatever residual opportunity the 968 market offers, for them to bother with any of this.. not even sure they made a catback for the 968 for years now, have they ?
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#60

yeah - that's the one i saw before. the numbers are definitely suspect. it's definitely not what mike said the other day, and when i called him after you sent me this chart back then, he also said it was a typo, and not from a 968. at least that part is consistent.



i'll try to pull up the real charts that others have posted on other sites. i've seen at least 2. as i remember, the best was 3hp gain at peak, and of course the big torque dip at about 3400.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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