Jatie_150 Guys do you need a new gasket for the pipe where it meets the manifold after you take the pre-cat out ?
BlackAstra2_2 Pre cat removed today. Smooth revving, no flat spots and a better sound through my stainless mongoose system. Anyone thinking of doing this mod shouldn't delay, especially if you've already done the ecu remap, derestricted the air box and fitted a straight through cat back exhaust system. I was expecting it to be difficult to remove and really hard to drill out but everything went smoothly and only took a couple of hours. Well worth it. Thanks to everyone who has posted about removing the pre cat. It certainly helped me. Cheers.
Mark_Dj Good, nice to hear you have also done this mod 😃 . It is well worth it and gets rid of those flat spots 🙂. Glad you found the info on here a big help 😃
Gazza BlackAstra2.2 said: Pre cat removed today. Smooth revving, no flat spots and a better sound through my stainless mongoose system. Anyone thinking of doing this mod shouldn't delay, especially if you've already done the ecu remap, derestricted the air box and fitted a straight through cat back exhaust system. I was expecting it to be difficult to remove and really hard to drill out but everything went smoothly and only took a couple of hours. Well worth it. Thanks to everyone who has posted about removing the pre cat. It certainly helped me. Cheers. well done mate i have to say it's the best mod i have done yet 😃
K70_RAF I heard not every astra 2.2 has this pre cat in. Is this true? If so can you find out if yours has without taking it all apart.?
Gazza yes it's true the later models didnt have pne i beleave notsure.gif the only way to check is to take it off you can take the 3 bolts of the manifold pipe and feel in and you should be able to tell if it's there or not 😃
Andy BlackAstra2.2 said: Pre cat removed today. Smooth revving, no flat spots and a better sound through my stainless mongoose system. Anyone thinking of doing this mod shouldn't delay, especially if you've already done the ecu remap, derestricted the air box and fitted a straight through cat back exhaust system. I was expecting it to be difficult to remove and really hard to drill out but everything went smoothly and only took a couple of hours. Well worth it. Thanks to everyone who has posted about removing the pre cat. It certainly helped me. Cheers. well done mate, its a great mod cos its free and gives upto 8 bhp ( so i heard anway)
Blue_2_2 Just had my pre-cat removed and a 200 cell sports cat welded in, then a power run done. Gains: 10 BHP at 5000 RPM 18 Ft/lb torque at 4000 RPM 1 Bhp at red line It pulls harder from lower rpm (no flat spots) and sounds better.
Blue_2_2 They supplied it for £80 no sure who made it. BTW: Emissions at idle my CO% is 0.001 the limit is 0.5% :shock: at High idle it 0.1% limit is 0.2% (is this good?)
Blue_2_2 oops sorry, its on the other thread i wrote "Frankenstein motorsport" http://www.frankensteinmotorsport.co.uk/index.asp 01525 237111
Mike Thats seems like a very good price. I have just been quoted £275 for a full new downpipe section without precat and for a 200 cell sports cat. Does that sound fair?
Mike Just had a thought, I actually had my cat replaced 12 months ago at an ATS garage. Is the pre cat built into this section that leads from the main cat to the engine or does that connect upto the downpipe section where the precat is?
