Do I Need One?
Thread Starter
Instructor
Joined: Apr 2008
Posts: 142
Likes: 11
Do I Need One?
Ok, first thank you in advance to all those who can help out with this post…
Here is what I have done to my 1999 C5:
-K&N cold air intake
-Long Tube Headers
-X-pipe
-Stock Catback
That’s it.
My question is, do I need a tune? After the LT install it is definitely running a little slower than with just a CAI. I ask because I do now want to run too Lean/Rich and mess things up internally, I do plan on putting a cam in it nearing the end of summer so if I could get by SAFELY (HP gains aside) with no tune, I wouldn’t mind. If not, then I was planning on going the route of a basic tune and then getting it fully tuned after the cam…Input/thoughts?
Thanks for the help,
Chris
Here is what I have done to my 1999 C5:
-K&N cold air intake
-Long Tube Headers
-X-pipe
-Stock Catback
That’s it.
My question is, do I need a tune? After the LT install it is definitely running a little slower than with just a CAI. I ask because I do now want to run too Lean/Rich and mess things up internally, I do plan on putting a cam in it nearing the end of summer so if I could get by SAFELY (HP gains aside) with no tune, I wouldn’t mind. If not, then I was planning on going the route of a basic tune and then getting it fully tuned after the cam…Input/thoughts?
Thanks for the help,
Chris
Le Mans Master
Joined: Feb 2007
Posts: 9,296
Likes: 1,531
From: Oviedo Florida
2024 C5 of the Year Finalist - Modified
2024 C2 of the Year Finalist - Modified
2023 C2 of the Year Finalist - Modified
2021 C2 of the Year Finalist - Modified
2016 C5 of Year Finalist
I would so that you will get the most hp from your add on's.
Good luck let us know your new rwhp.
Good luck let us know your new rwhp.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Absolutely-----you need a tune--It is quite normal after LT's to have very little or no gain after an install--- The reason LT's are illegal in some states is because of the 02 bung locations are moved to accomodate the individual runners and moved more downstream-- This gives the 02's erroneous readings in closed loop AFR or part throttle fueling--Typically it makes the fueling way rich in CL----Even though the ECM is asking for a 14.68-1 AFR you are prob. somewhere closer to 14.2
---The PE fueling or WOT can be all over the place--and deff needs to be checked---Another issue is that the stock manifolds are thicker and deaden some of the engine noise--the thinner LT's tubes will create new engine sounds that the Knock sensors will mistake for pinging or detonation---many times you'll have to "desensitize" the knock sensors to avoid this false knock--
---The PE fueling or WOT can be all over the place--and deff needs to be checked---Another issue is that the stock manifolds are thicker and deaden some of the engine noise--the thinner LT's tubes will create new engine sounds that the Knock sensors will mistake for pinging or detonation---many times you'll have to "desensitize" the knock sensors to avoid this false knock--
