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Discussion Starter #1
Somewhat dissappointed in my dyno results when adding these two parts. 478rwhp 349rwtq. My AA exhaust w/o a pulley was 480rwhp 349rwtq. I didnt dyno again when I removed the exhaust so I cant say the actualy gain from the pulley and exhaust. I was expecting mufflers+pulley to make more power then just the AA exhaust. I am happy with the sound though. The dinan exhaust is a good combo with the headers. This was on a dynojet so a pulley gain should have been measured correct?
 

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Crazy, I'm kind of surprised. Are you selling your exhaust? If so, I might be interested.
 

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Discussion Starter #5
Its already been sold. I took the AA exhaust off for two reasons
1. it was louder than I wanted in my only car once I added headers
2. with the headers and no cats setup there is a lag in throttle response(if you do a search there are better explanations)
 

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Discussion Starter #6
I got a chance to open it up a few times on my way home from the gym. It definitely feels faster even with 3 people in the car. The two passengers have been in the car many times and also said it feels faster. It must have picked up a decent amount of midrange. I didnt pick up the car until they were closing so Ill get them to send me a chart with AA setup and pulley/dinan setup.
 

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Somewhat dissappointed in my dyno results when adding these two parts. 478rwhp 349rwtq. My AA exhaust w/o a pulley was 480rwhp 349rwtq. I didnt dyno again when I removed the exhaust so I cant say the actualy gain from the pulley and exhaust. I was expecting mufflers+pulley to make more power then just the AA exhaust. I am happy with the sound though. The dinan exhaust is a good combo with the headers. This was on a dynojet so a pulley gain should have been measured correct?
Honestly, I'm not sure if it would measure or not. I personally haven't
been witness to a dyno that has shown an increase in numbers from a pulley.
I've speculated that a dynojet could show them due to it measuring
hp/tq from accelerating a drum. There are a few dynos on the board
that have shown increases.

It's too bad you didn't have a Dinan only run. Correct me if I'm wrong
but doesn't the AA exhaust include an x-pipe? Did you keep this?
 

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Discussion Starter #8
It's too bad you didn't have a Dinan only run. Correct me if I'm wrong
but doesn't the AA exhaust include an x-pipe? Did you keep this?
The AA exhaust is a sec. cat delete, x pipe and mufflers. I sold it together and put my full stock exhaust back on. Then added the pulley and dinan mufflers.

I got 10rwhp 10rwtq from AA exhaust before the headers. If you figure I lost that same amount when taking it off with the headers on then I gained 8rwhp and 10rwtq by adding the pulley and dinan mufflers. :dunno:
 

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cjm6,

I know you mentioned a lack of throttle response with headers & AA exhaust...

Was the throttle response an issue pre-headers with the AA system?

Thanks!
 

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Dont you think you got more from your AA setup cuz your cat deleted and had the x pipe?
 

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Discussion Starter #11
cjm6,

I know you mentioned a lack of throttle response with headers & AA exhaust...

Was the throttle response an issue pre-headers with the AA system?

Thanks!
No, its from headers and straight pipes. Other members with headers have noticed it with different straight pipe setups as well.
 

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Discussion Starter #12
Dont you think you got more from your AA setup cuz your cat deleted and had the x pipe?
Well the AA setup gave me 10rwhp and 10rwtq and I was assuming that the dinan mufflers and pulley would give me more than that.
 

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The AA exhaust is a sec. cat delete, x pipe and mufflers.
You have to compare both. Did the AA setup include a cat delete plus the x-pipe and the dinan set up included mufflers with cats and mid section resonators ?

I find it hard to believe that 1 set of mufflers plus pullies is less powerful than another set of mufflers without pullies.
 

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Guys,

Exhaust alone does practically nothing in the gains department. The bigest gains are from headers and race cats. These cars like some backpressure and removing the secondary cats with aftermarket headers will result in little or no gains at all. I would not recommend deleting your secondary cats. You're much better off leaving your headers stock, putting in 100 cell secondary cats and leaving your exhaust alone. You WILL get noticeable gains.
 

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You're much better off leaving your headers stock, putting in 100 cell secondary cats and leaving your exhaust alone. You WILL get noticeable gains.
Where can you get these 100 cell secondary cats? If I were to keep stock headers, is this better for performance gains than simply deleting the secondary cats? Deknight says that deleting secondary cats with stock headers will give 15 whp increase, can the 100 cell secondary cats give that much also?
 

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The exhaust on the M5/M5 is VERY complicated and their is no one way to pin point where the gains would be. We've done several dyno runs (high flow cat vs stock cat, stock sec 1, with straight 2nd and 3rd, stock 1-2 with aftermarket sec 3, etc.) and its very easy to lose power from the wrong exhaust set up. In defense of the exhaust set up you have now, was the person that did the dyno run the same person as last time? And how much experience does he have dynoing cars like this. Since the dynojet is based on drum acceleration rate, its easy for numbers to be different based on how the sample run started.
 

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Discussion Starter #20
You have to compare both. Did the AA setup include a cat delete plus the x-pipe and the dinan set up included mufflers with cats and mid section resonators ?

I find it hard to believe that 1 set of mufflers plus pullies is less powerful than another set of mufflers without pullies.
The comparison is AA mufflers, xpipe and cat bypass vs Dinan mufflers and RPI pulley.
 
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