Anyone have stock RWHP/TQ for 993TT?
07-03-2007, 04:08 PM
#31
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Originally Posted by shawsan
"Using standard mufflers with 100 cell cats is pretty pointless, the stock mufflers will cancel out any extra flow from the cats." Quote
If this is a generalization that's true, then I just wasted $3K installing Hyperflow cats (100 cell) on my Challenge Stradale, while leaving the OEM mufflers in place. Yet, in the case of the Challenge Stradale, two pre vs. post dynos confirm a performance gain. One set of dyno results, by Hyperflow itself, (and thus questionable), claims 28ft/lb torque gain at the wheels at 4500rpms. But then, another set of dyno results by a fellow who hates puffed up manufacturer claims and set out to disqualify Hyperflow, reports a 22 ft/lb torque gain at the wheels at 4500rpms. I thus have a tad of confidence some real performance gain is attributable to sports cats in my Ferrari. Would the exhaust system on a 9933tt be so different?
If this is a generalization that's true, then I just wasted $3K installing Hyperflow cats (100 cell) on my Challenge Stradale, while leaving the OEM mufflers in place. Yet, in the case of the Challenge Stradale, two pre vs. post dynos confirm a performance gain. One set of dyno results, by Hyperflow itself, (and thus questionable), claims 28ft/lb torque gain at the wheels at 4500rpms. But then, another set of dyno results by a fellow who hates puffed up manufacturer claims and set out to disqualify Hyperflow, reports a 22 ft/lb torque gain at the wheels at 4500rpms. I thus have a tad of confidence some real performance gain is attributable to sports cats in my Ferrari. Would the exhaust system on a 9933tt be so different?
The normal order of 993tt modification would be free flowing mufflers first followed by cats for more exhaust flow followed by no cats, bigger diameter pipes, no mufflers and finally a small length pipe straight out of the turbo.My early experience of the effect of cats/mufflers is pretty apt here.
I had a set of 100 cell cats (old style not the bigger ones available today) coupled with Mille Miglia mufflers ECU, K16 hybrids and FPR..... The package was quite nice, probably ~440hp.
The Mille Miglia mufflers had a nasty resonance right around cruising speed and so I took them off and temporarily put back on the stock mufflers. It got rid of the drone but there was a very noticable torque reduction (butt dyno).
You may however be correct that the cats on their own produce more torque somewhere - just a bit pointless when there is free power/responsiveness to be had with better mufflers IMHO
07-03-2007, 04:12 PM
#32
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This is a interesting thread... There have been a few people on this forum that have lived thru purchasing components and trying them..
Shawsan, your Ferrari, wasn't a aircooled turbo.. The STOCK mufflers are restrictive.. If you want to waste your time on the dyno by some muffler bypass pipes and then run the tests.. And then again, 100 cell cats aren't all equal.. You stock cats might be a better choice..
Shawsan, your Ferrari, wasn't a aircooled turbo.. The STOCK mufflers are restrictive.. If you want to waste your time on the dyno by some muffler bypass pipes and then run the tests.. And then again, 100 cell cats aren't all equal.. You stock cats might be a better choice..
07-03-2007, 06:56 PM
#33
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A couple of responses, with thanks for all the interesting feedback;1) The reason the Hyperflow cats may generate HP/TQ gains on my Challenge Stradale (CS) with OEM exhausts is (i) the OEM CS exhausts are specially produced for the limited edition CS by Tubi, and are different from 'regular' OEM exhausts, (ii) they have vacuum activated bypass valves that fully open at 4500rpms in 'race mode' under full throttle, 5500 rpms under full throttle in regular driving. These two factors increase flow from the sports cats and contribute to the unique CS sound, referred to as 'the devil on viagra'. For an interesting post, see http://ferrarichat.com/forum/showthr...t=devil+viagra
2) My understanding, and correct me if wrong, is that the Ruf version of the 993tt, with a 100HP performance gain over stock, had race cats whereas the OEM muffler stayed the exactly the same. If correct, why on earth would they do this if the OEM muffler would cancel out the effect of the race cats?
07-03-2007, 07:02 PM
#34
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Originally Posted by shawsan
A couple of responses, with thanks for all the interesting feedback;1) The reason the Hyperflow cats may generate HP/TQ gains on my Challenge Stradale (CS) with OEM exhausts is (i) the OEM CS exhausts are specially produced for the limited edition CS by Tubi, and are different from 'regular' OEM exhausts, (ii) they have vacuum activated bypass valves that fully open at 4500rpms in 'race mode' under full throttle, 5500 rpms under full throttle in regular driving. These two factors increase flow from the sports cats and contribute to the unique CS sound, referred to as 'the devil on viagra'. For an interesting post, see http://ferrarichat.com/forum/showthr...t=devil+viagra
Originally Posted by shawsan
2) My understanding, and correct me if wrong, is that the Ruf version of the 993tt, with a 100HP performance gain over stock, had race cats whereas the OEM muffler stayed the exactly the same. If correct, why on earth would they do this if the OEM muffler would cancel out the effect of the race cats?
