I am curious if anyone has done back to back dynos with tuning comparing true duals to single 2.5-3 inch Ypipes?
Thanks!
Chris

 

Before true duals - 318 rwhp, 326 rwtq
After true duals w/ x-pipe - 308 rwhp, 303 rwtq

However, I picked up 1.5 mph in the 1/4...?
In any case, I went beck to the y-pipe setup becuase the duals were WAY too loud and I do a lot of highway driving.

 

I've seen a H/C car loose HP with true duals with no type of H or X pipe.
Also going from MAC's to LT's wasnt' much of a difference on his either.

 

LTs are mainly for sound. yes they gain midrange TQ, but hardly enough to justify the money. face it, the MAC sound terrible, but flow great!

also you will need an H or preferrably X pipe or you will lose power on the dyno. i dont know about the track. i have stuck with my ole 2.5" y-pipe - seems to make good power to me! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by gator's 99TA:
<strong>face it, the MAC sound terrible, but flow great!
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Care do explain? so the LTs are deeper and sound better?

Drew

 

Best I can tell you is from a stock A4/1998 car with a small cam and stock heads:

Before - Mac Headers (with CATs) and B&B Triflow

After - Dynatech headers (no CATs) with 2.5 true duals through Flowmasters

About a 14rwhp across the entire range. I do know the car responded much better at the track on the bottle though. I'd say 8-10 rwhp was through the removal of the CATs. So I'd say about a 5rwhp gain without considering CATs.

 

thanks man <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Cheers,
Chris

 

Why have so few people gone from a y to duals and dyno before and after.

Usually the ones I hear about are the ones losing power.

Surely, someone has had good results. I'd like to know too.

 

there are some good results but they are people that were stock to duals. people that went from a good 2.5/3" y-pipe with a good collector are not going to gain much if any at all.

now most that LOSE power are the ones that did not put a good x-pipe in the middle to create exhaust velocity and good pulse. otherwise it is not as good. still, not a great mod if you have a good flowing y-pipe!

 

I think verbs has a before and after dyno gaining 8 rwhp or so at the bolton level, also flattened out his powerband big time.