Engine/Transmission (1998.5 - 2002) 4 or 5 inch exhaust?

[dlange]

Does 5 inch exhaust make a little more power when going over 500 horse? Or will a 4 inch be just fine up past that level.

 

[Mark Craig]

Is 5 too big

dlange,



What you will find per atricles in the TDR magazine is until you get to 500 RWHP a 4 inch system will do all you need and more and actually help keep your low rpm performance a bit better in off line starts etc. If you plan to get to 500 hp but stay at or below that level a 4 inch is all you need, over that an you'll need the 5 inch for EGT reduction, it might make a little more HP (a little) but EGT is what you're after at that HP level.



Mark @ DPPI

 

[Cooker]

Re: Is 5 too big

Originally posted by Mark Craig



What you will find per atricles in the TDR magazine is until you get to 500 RWHP a 4 inch system will do all you need and more and actually help keep your low rpm performance a bit better in off line starts etc.

What I don't understand is that at one time there were several 3" vs 4" debates (when the cheapest 4" system was $500). There were some people saying that the 3" would spool up better and performance between a 3" system with a good muffler and a 4" system would be almost identical. Then there were a ton of people that disagreed with this saying the backpressure is the worst thing for a turbocharger and the less the better for overall performance. There were some very well respected names in on this debate too.



Now a similar thing is happening with the with the 4" vs. 5" I have seen this several times now. I just wanted to comment on it because maybe the guys saying 3" was alright were right after all?



Just some food for thought.



dlange,

Sorry to get off track. In response to your question there was a member who was running twins with a 5" downpipe and a 4" exhaust. He said after going to a complete 5" exhaust the truck ran much better and was more responsive. I don't know what HP level he was at. If you are thinking twins it seems 5" is the way to go.