Thread: 3 inch exhaust
View Single Post
  #5  
Old 11-09-2021, 11:48 AM
leeklm's Avatar
leeklm leeklm is offline
Ultimate Warrior
 
Join Date: Mar 2013
Location: Mpls, MN
Posts: 1,747
Default

Quote:
Originally Posted by OCMDGTO View Post
If you're chasing a timeslip then yes it's worth it. If your just cruising on the street then probably not. I picked up a couple tenths going from 2.5 full mandrel bent to 3" from manifolds to mufflers w 2.5 tails. If I had it to do over I would go all 3 but was concerned with fitment around the 9" rear.
Agreed. Another example on minimal impact of smaller pipes down stream... I have full 3" mandrel pipes with Ultraflow mufflers. For improved fitment, the 3" tail pipes are necked down to 2.25" chrome tips. I ran back to back 1/4 mile runs with and without the tips and zero difference on ET or MPH.

Of course the exhuast gasses have cooled considerably by the time they reach the tips, and the tips are only 10" long.

I have since installed cutouts after the H pipe when I race, which did provide an extra 1/10th or so compared to full exhuast.

As mentioned, if mostly street i would use a 2.5" mandrel bent system and reduce hassels of the larger pipes.

Sent from my SM-G965U using Tapatalk

__________________
68 Firebird-- Street/Strip - 400/461 Eagle Forged Bottom End & Ross Flat top pistons. KRE 325 CFM D port, Ultradyne 263/271 @.050, .4267 lift. Crower Solid roller lifters and 1.65 stainless rockers. Quickfuel 1000 on Torker2 intake and 2" open spacer. Hedman 1.75" headers. TH400 w/brake. Ford 9" w/3.80 gears & 28x9 Hoosier pro bracket drag radial. Best ET: 1.35 60ft, 6.29 @ 107.20 mph, 9.99 @132.33 mph. 3,300 race weight
The Following User Says Thank You to leeklm For This Useful Post: