M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: laernu on June 12, 2009, 09:59:24 AM

Title: Straight Pipe
Post by: laernu on June 12, 2009, 09:59:24 AM

how thick should i make the piping for a straight pipe on a stock motor on a 91 318is, i was thinking about 2.5" i dont wanna lose any back pressure so if someone can get me a really good setup going im hoping to get this done in about 2 weeks

Title: Straight Pipe
Post by: 1991 E30 M42 on June 12, 2009, 12:02:07 PM

Quote from: laernu;73518

i dont wanna lose any back pressure

isnt that the point of a straight pipe.

Title: Straight Pipe
Post by: xwill112x on June 12, 2009, 12:20:33 PM

Quote from: 1991 E30 M42;73523

isnt that the point of a straight pipe.

ahahaaha

Title: Straight Pipe
Post by: RidingSimple on June 12, 2009, 12:21:53 PM

Be prepared for a whopping zero increase in hp and about 3 trillion db's of annoyence added.

Title: Straight Pipe
Post by: Hodge on June 12, 2009, 02:20:07 PM

Straight pipes on stock M42's is stupid.

Actually, straight pipes on any street driven car is stupid. Just asking for trouble and not even a noticeable gain from it, not to mention horrid noise levels.

Title: Straight Pipe
Post by: 1991 E30 M42 on June 12, 2009, 05:55:40 PM

you will only see a power increase if it is a high compression motor with a bit more valve overlap than normal

Title: Straight Pipe
Post by: derek9702 on June 12, 2009, 06:04:21 PM

Don't forget the Whistle Tip on it.....woooooo wooooo

Title: Straight Pipe
Post by: JP 91iS on June 12, 2009, 06:54:36 PM

Quote from: derek9702;73543

Don't forget the Whistle Tip on it.....woooooo wooooo

no, that's just for decoration

Title: Straight Pipe
Post by: quinn11m20 on June 12, 2009, 07:39:49 PM

I saw the WOO WOO whistle tip on you tube. That shit was funny. Hey just to let you know I cut off my exhaust just after the O2 sensor. No HP gain, really obnoxiously loud and just overall sucked. DON'T DO IT.

Title: Straight Pipe
Post by: laernu on June 12, 2009, 11:39:21 PM

alright thanks for the feed back lol

Title: Straight Pipe
Post by: papercutout on June 13, 2009, 05:30:50 AM

UK cars have 1 front box, 1 midbox and 1 backbox, no CAT. I've chopped the midbox out (kept front box to keep some backpressure) and have a cherry bomb rear. Yes it is pretty damned loud (I'd have a quieter backbox if I was you!), but I have noticed some small gains, especially once I changed the injectors too, I've got vauxhall vectra 2.5 v6 ones on there atm and its helped.