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My search for more NA power (Dyno time)

272K views 1K replies 109 participants last post by  radichev 
#1 ·
Hey Guys,

Just wanted to start this thread to document where I'm going with my car. I'm a big fan of dyno results versus butt-dyno feeling. I like to make sure I get some bang out of my buck. Hopefully this thread will give people some reference when they are looking for NA mods.

If you have any good solid before/after dynos (corrected numbers) feel free to post them with an explanation. I'll start off by posting what I have so far....
 
#128 ·
Yeah. I'm a bit disappointed. I wasn't expecting gobs of power, and I'm just glad that I didn't have a real loss. Honestly, I think the only reason it's showing a HP loss is due to less spiking up top. I really think humidity attributed to it, too.

Exhaust is being welded up as we speak. If it's a bust, I'm going to be pretty upset...
 
#134 · (Edited)
Another:



At this point, it'll be one piece. I'll probably have a vband welded onto the rear section after I get it dyno'd. Don't want to sink any more cash into it until I see that it's made some power for me. I hope I'm not in the market for a new Magnaflow exhaust in a month....
 
#140 ·
Yes and no. I'm happy with the piping, and the sound is growing on me. Definitely deeper. I feel like it's holding back a little in the high rpms, now. Chad (Stett) said he was worried about the y-pipe. He said it was going from 2-2.5-3. He said that might cause some loss up top. I won't know until I hit the dyno.

Unhappy with the tip, but I didn't pay for a nice one because I wanted to make sure I was happy with the performance.
 
#141 · (Edited)
Smart move, dont play with it untill the dyno. Even if it stays around the same hp, the weight alone makes this worth it, I bet it weighs a good amount less than the magnaflow.

Edit: Speaking of weight, did you remove the rear seats? I did about a week ago along with a mini cooper battery and the car feels great. I'm going to get a custom mat to cover the seat. I'm getting it made by the same guy who did this
http://www.m3forum.net/m3forum/showthread.php?t=265830&highlight=rear+seat+delete
It's going to look similar except will say "bmw performance" and cover the entire bench part as well. Let me know what you think.
 
#146 · (Edited)
I was at my shop the other day.. I saw an OEM Y-pipe. I asked what it was from and my bro said it was from a later model e46. I'd assume bmw didn't switch for nothing. Either way before you dyno, I want your exhaust just pm me. I was going to make the exhaust you fab'd based on the oem y pipe. IE distance from the headers to the connection. I'm curious to see the distance from the headers to the Y pipe and how you chose that distance!!!
 
#151 ·
This may be a silly question, but I'll ask anyway. My headers are Swain coated, so they're getting some good insulation. Right when it hits the Y-pipe (which is going from around 2 inch to 2.5 at the merge and then opening up to 3) I would imagine the exhaust is starting to cool. I would think that would be a bad place for that to lose velocity. I have a roll of exhaust wrap. Does anyone think I would benefit from wrapping the y-section and back into the 3-inch by a foot or so?
 
#159 · (Edited)
hmm i just had a thought. How would you lose power when you bored out the TB? Since you didn't gain any HP, that means that there is a bottle neck somewhere in the manifold or the head. Which means that the same amount of air is going into the motor, therefore making the same amount of power. How is it possible to lose power? Am I right? I remember you saying the humidity was almost double your last run... that's probably what caused the drop in power, not really the tb.

...or did we all know this and i just realize it? :rofl:
 
#164 ·
Hopefully there's a positive difference!



I'm getting under the car to do my differential bushings this weekend, I'll get some good pictures of the y-pipe.

BTW, I know it's a different motor, but Bimmerworld's new 3.5 inch single for the M3 looks great. What I notice, though, is that the Y section isn't super close to the flanges, so I'm not really concerned about my distance, more concerned about the size of the merge. Might be calling up Dr. Gas in a couple weeks.

http://store.bimmerworld.com/bimmerworld-e46-m3-race-exhaust-p1474.aspx
 
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