Ref. Heat shield: 2.5" to 3" or full 3" downpipe?

[696]

I have heard you guys say that w/ a 3" downpipe you will melt the A/C fan cause you have to remove or mod the downpipe heat shield (how hard is it?). Can you use the downpipe heat shield w/o moding it with the downpipes that start at 2.5" then go to 3" after the flex pipe? Do you really need a full 3" downpipe or are the marketing people telling the truth when they say the first section of downpipe can be 2.5" w/o losing any flow cause the gasses are so hot?
696

 

[doug]

Originally posted by 696
Can you use the downpipe heat shield w/o moding it with the downpipes that start at 2.5" then go to 3" after the flex pipe?

Yes, unless you have an O2 eliminator downpipe.

Originally posted by 696
Do you really need a full 3" downpipe or are the marketing people telling the truth when they say the first section of downpipe can be 2.5" w/o losing any flow cause the gasses are so hot?

I believe 2.5" for the front part is fine. Road Race Engineering says so, and they know their stuff. (Actually, I believe 2.5" is fine for the whole exhaust unless you're running 11s or better, but that's another story...)

 

[turboholic]

-I have the 2.5-3" D/P without heat shield, no sign of deformation on A/C fan.

 

[696]

I would like to keep the downpipe heat shield but I'm worried about boost creep with the a ported O2 housing. Should I have a problem with boost creep or should I be safe and get the O2 eliminator. OR.....get the full 3" downpipe w/ O2 eliminator and mod the heat shield? Decissions, decessions.
696

 

[doug]

From what others said when I asked about hacking the heat shield, it doesn't sound too hard. I don't even have my heat shield any more, though, so I gotta get another one. If you're worried about boost creep, then definitely get the O2 Elim.

 

[696]

I'll prob. see which I can get the better deal on and go from there. I don't know if I am going to have a problem w/ boost creep but just trying to prevent it.
696