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-   -   need opinions on my exhaust (https://www.rx7club.com/1st-generation-specific-1979-1985-18/need-opinions-my-exhaust-822233/)

black82gsl 02-24-09 05:17 PM

need opinions on my exhaust
 
I got the header witch I put a 3" collector on witch runs into a 3" glass pack and then reduces to 2.5" and then threw another 3" glass pack under the bumper into a Magnaflow tip. I know its really loud right now since I put the header on it. Its a 12a stock port with race beat Holley set up with the header and exhaust. Tell me what u guys think? I am sure u guys will dig my sweet slippers I was wearing...lol.
Heres the link
http://vids.myspace.com/index.cfm?fu...deoID=52978752

black82gsl 02-24-09 06:05 PM

here's another from a further distance
http://vids.myspace.com/index.cfm?fu...deoID=52982348

PercentSevenC 02-24-09 07:00 PM

Crikey, that's a lot of smoke.

Why are you going from 3" down to 2.5" and back out to 3" again?

thunkrd 02-24-09 07:02 PM

i'm guessing you get more performance out of that?

Hyper4mance2k 02-24-09 07:58 PM

bad guess... 3" on a stock port isn't going to make much power though. It's way too much pipe and not enough velocity. You would've been better to collect into 2.5" and keep it that. you're not going to have much velocity so it's going to kill your lowend tq. You'll make more power above 7k though. even though your stock 12a is going to be wheezing that high. not enough flow through stock ports to make any power above 6500 rpm really. so you'll make say 95 whp at 7k as opposed to making 90 with 2.5" exhaust, but you're going to probably make peak power at 6500 rpm at about 110whp with the 3" but you would've made probably about 115 at 6300 with 2.5"

thunkrd 02-24-09 08:03 PM

lol. yes. i was just wanting to see what he says about it

4portgsl 02-24-09 08:06 PM

Its plenty loud, too loud for me. Glasspacks are really loud on rotaries, usually because they have a tendency to melt.

Hyper4mance2k 02-24-09 08:12 PM

1 Attachment(s)

Originally Posted by Hyper4mance2k (Post 8994972)
bad guess... 3" on a stock port isn't going to make much power though. It's way too much pipe and not enough velocity. You would've been better to collect into 2.5" and keep it that. you're not going to have much velocity so it's going to kill your lowend tq. You'll make more power above 7k though. even though your stock 12a is going to be wheezing that high. not enough flow through stock ports to make any power above 6500 rpm really. so you'll make say 95 whp at 7k as opposed to making 90 with 2.5" exhaust, but you're going to probably make peak power at 6500 rpm at about 110whp with the 3" but you would've made probably about 115 at 6300 with 2.5"

kinda like this if you know what I mean
https://www.rx7club.com/attachment.p...1&d=1235527945

thunkrd 02-24-09 08:17 PM

why'd you use the 3" anyway?

black82gsl 02-24-09 09:23 PM

there was some smoke but not as much as u think it was like 15 degrees out when I shot the vid! And I used the 3" glass paks cause i had 2 new 3 inch glass packs laying around so i used them. And on the header when I bought it it had like a 1.5" outlet flange on it so i welded on a standard "v8" header reducer on and it actually has a reducer straight to 2.5" and the it runs 2.5" until it gets to the first glass pak were the pipe is exspanded to fit it and then goes back to 2.5" so basically its all 2.5" except for the g paks them selves. Heres a pic of the header to make it easier to get what I am sayin............
http://i58.photobucket.com/albums/g2...Picture032.jpg
http://i58.photobucket.com/albums/g2...Picture033.jpg
I will soon find out what kind of power it actually makes there a local pro street shop that I know who is getting a chasis dyno next month and I'll prolly get it tuned on there.

Super82 02-24-09 09:44 PM

I dig the sound alot. Kudos!

I'm getting my RB muffler soon. It was the easy way out...but I kinda wished I dig something kick arse to get something original and awesome sounding like that. Who knows, I might love my RB but all the vids I've heard of RBs have sounded pretty weak. Yours sounded high pitched, winey and screamy. Love it. Hopefully you can live with the volume, and keep it sounding that way and getting performance.

black82gsl 02-24-09 09:48 PM

Thanks,like I said hoping to get it dyno tuned in the next month or so. I will know then what I got?


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