Author Topic: Straight Pipe (Read 4857 times)

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

1991 E30 M42 · « **Reply #1 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.

xwill112x · « **Reply #2 on:** June 12, 2009, 12:20:33 PM »

Quote from: 1991 E30 M42;73523

isnt that the point of a straight pipe.

ahahaaha

RidingSimple · « **Reply #3 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.

Hodge · « **Reply #4 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.

1991 E30 M42 · « **Reply #5 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

derek9702 · « **Reply #6 on:** June 12, 2009, 06:04:21 PM »

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

JP 91iS · « **Reply #7 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

quinn11m20 · « **Reply #8 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.

laernu · « **Reply #9 on:** June 12, 2009, 11:39:21 PM »

alright thanks for the feed back lol

papercutout · « **Reply #10 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.