How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Engineer
Category: Jeep
Satisfied Customers: 21620
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
Type Your Jeep Question Here...
Matt is online now
A new question is answered every 9 seconds

Sahara 4.0: , I have a 4.0 wrangler from 2000 and using it

Customer Question

hi, I have a 4.0 wrangler from 2000 and using it only for offroad racing. With the stock engine on it, how do I obtain the best engine performance, in what exhaust and cat concerns? thanks
Submitted: 2 years ago.
Category: Jeep
Expert:  Matt replied 2 years ago.
Hello providing you stick to a 'catback' exhaust system then you won't have any issues about passing emissions checks ( if you're concerned about that ) and I'd go for at least a 2.75" to 3" system to minimize back pressureI'd also fit a free flow drop in panel filter such as K & N to increase air flow and then look into a ECU re-map to allow some extra fuel and increase spark timing you can also go for a 'header' manifold to increase flow and fit a high flow cat to further reduce back pressure as with all these things going much further is diminishing returns and if you want a big hike in power then its time to consider forced induction
Expert:  Matt replied 2 years ago.
do you still need help?