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Discussion Starter #41 (Edited)
BMan5150 said:

Bierbelly - did you do just one run or severalruns on the dyno? If you did more than one run, could you post those dyno numbers too? How about your pre-Flow dyno numbers? What were your worst dyno numbers on the pre-Flows you are comparing your post-flows too?
In all cases, I've posted best dyno run (usually the third) against best dyno run. Each time I've been they've done three, except this last time, when run #3 screwed up (I think the lead was being interfered with by one of the spark plug wires), and they did a fourth. So the data that's up top was pre-Flow best v. post-Flow best. I'd have to look back at the sheets to get the lowest numbers. However, while the runs were done about 6 mos apart, they were done on the same dyno. And yes, I recognize that conditions are different (though they're supposed to be corrected) and that even the same dyno has a margin of error (wonder how much from run to run?), but one thing's clear, I certainly did not GAIN any HP/TQ with the Flows. Another thing is clear too, they still sound a lot better than stock.:D

PS. Hey, do us a favor and dyno again just before and just after you have the CB put on. Some seem to think that the welded in Flows might be a problem, since the stock tubing is smaller diameter than the Flowmaster Catback. Maybe you'll get an increase, who knows. But I've decided to dyno after every change to see if there's really any gains to be had, and if so, about how much. Trying to be informative to the members.
 

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Check out the Spin Tech. I've used them and they work and sound really nice. I'm thinking about picking them up in my line, but haven't yet. Just impressed by them. Deap at idle and have a slight Flowmaster sound at wot. Sounds real nice with Dr.Gas X.
 

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Looking at bierbelly's sig line, I see he has headers and free-flowing mufflers...but, stock h-pipe? It wouldn't suprise me to see weird dyno numbers with such a bottleneck right in the middle of the exhaust system. Also, how long was it in between dyno runs? Hell, old spark plugs can cost you hp. Considering 99+ GTs are getting around 220rwhp, i think your numbers are pretty good in any case.
 

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When I had my flows welded in it seemed to pull a little harder up top, but that may have been mind over matter. But, I had 2.25" flows welded in so they matched the stock pipes and didn't require any spacers.

I've been to the track many times and I consistently have run a little better after each successive mod. I'm sure I improved as a driver as well, but I never got slower after doing any of my mods. It seems that there is little or no gain with chambered mufflers, and maybe a little from straight through mufflers.

I do love the sound, regardless of the performance gain :p
 

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Discussion Starter #45
Wolfie351 said:
Looking at bierbelly's sig line, I see he has headers and free-flowing mufflers...but, stock h-pipe? It wouldn't suprise me to see weird dyno numbers with such a bottleneck right in the middle of the exhaust system. Also, how long was it in between dyno runs? Hell, old spark plugs can cost you hp. Considering 99+ GTs are getting around 220rwhp, i think your numbers are pretty good in any case.
Not to worry, the catted H will come. But T/A is next mod, sitting in the garage and patiently awaiting install. Do have new platinum plugs. 6mos between dyno runs, so I know it's somewhat inconclusive, but a loss if anything at all. No gain for sure.
 

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I've recently cut my factory tailpipes off and dumped right off the back of my 2-1/2" flowmaster 2ch's. This freed the car up a bit across the board. I've now become an opponent of welding into the stock cat-back, especially given some of the recent exhaust dyno articles in MM&FF and 5.0 magazines.

My 2 cents...
 

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My Snake's 4 baselines varied by as much as 12 HP within a 30 minute timespan. Every dyno run is different, every car is different.

I wouldn't worry about your Flows, they're not hurting you. Just enjoy the sound.

If you want gains from behind the H pipe, a mandrel bent system is the only really effective way to get more HP. Weld-ins are just for sound.
 

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The dyno is slightly diffrent with every run and the car is slightly diffrent with every run, hell even conditions can change between runs. Also, you could have a bad welding job on your mufflers, and the fact the the tube size is diffrent doesnt help either, and the stock tubing isnt great to begin with. I had the 30 series 2.5 flowmaster cat back put in mine, and had a decent SOTP increase and I could spin the tires better. Plus it does sound alot better:D(I cant wait to put my bbk lt's and o/r H on:evil: )!!!
Dan
 
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