ringram

[kaw]

going to take cats out ,can you c any problems this may cause know we may have to change the tune a little.not worried about mots just think it would be a better flow and CHEAP

[k15tox]

kaw said:

going to take cats out ,can you c any problems this may cause know we may have to change the tune a little.not worried about mots just think it would be a better flow and CHEAP

im no expert but i think if you take the cats out without tuning it will run crap and you will lose power, due to massive overfueling.

not sure about ls1's, but most modern vauxhalls go into limp home mode when the cats are removed without a tune.

bottom line, you will need a tune

kyle

[kaw]

running mafless tune and plan to keep the lambers in so would that still over fuel,asking for advise off anyone that can help

[stigmundfreud]

having logged with 100cels and then with bypass pipes there was next to sod all in it but the car by that time was tuned

[ringram]

Should be fine as stig says. You will probably have to disable post cat OS sensor codes to prevent light coming on though.
How much power depends on how restrictive they are. Cats in VXR8 are right up high to the exhaust. You will need some fancy bends in your bypass pipes.
They say they arnt that restrictive.. It might not be worth the cost of the bypass pipes and fitting unless you are going to do it yourself.

[stigmundfreud]

can confirm identical tune, bypass pipes and with cats no difference at all. Sound wasnt even really any different.

[kaw]

130 pounds for two stainless fitted ,was going to put dus on dyno for garth to get more info on gains then repeat wiyh bypass pipes if theres any gains might be cheap bhp.rich need some info on a good cam

[ringram]

I was going to go 224/230-114 XER Compcams in my LS2 but wasnt sure about emissions. It could scrape through. Or the 224/228 even less overlap. I figured the 230 was better for the stock exhaust, it also seems to be a popular L92 choice for a later headswap I was going to do... The 224/228 is a popular choice for the cathedral heads, aka LS2 etc.

You will also need valve springs etc. I thought Gareth was on the case?

[kaw]

gareth is helping me ,he as been great ,just doesnt hurt to ask the guys that know for advise aswell.think he will have a lot on his plate next year with the gts and ute,hope he lets me give him a hand on the spanners

[ringram]

Yep he needs bigger heads and cam on the GTS