hi there, thinking of fitting decat headers to my gt4, will this throw up an engine warning light? and if so will that do anything to the car like restricting power etc?
many thanks

 

short answer, yes. You will need a tune to run catless or minicats or both.

 

I do want to get it mapped in time but was wondering if I could put the decat exhaust in and map it a few weeks later, I don't mind the engine light being on just wondering if it will limit power or something due to the check engine light being on?

 

Cargraphics, Soul, Fabspeed, you probably will get an immediate check engine light. Dundon seems to go pretty long without one coming on, but I hear eventually they will also trigger one.

 

okay thank you, I don't mind the check engine light for a few weeks, but do you think it will hold back power and performance due to the light being on?

 

No, you should not have any issues.

 

That's not true, I went over 1000 miles with no check engine light, then I got the car tuned so essentially never had a light come on

I use o2 spacers.

 

see my first post

 

We've seen 981 GT4's go 1,000+ miles without a CEL and also pop one in a mile with catless headers. I would expect one, it's just a matter of when. O2 spacers have a good result in preventing them on this car as well.

-Mike

 

I have the Dundon race headers. They are supposed to come with mini cats for the secondary o2 sensor. Mine accidentally came without them and the shop that installed them didn't realize they were to be included so they installed and I ran with no CEL for around 50 miles before CEL tripped. Got in touch with Dundon, they immediately sent the missing mini cats but went on an Appalachian driving weekend before I received them with the CEL and some spirited lead-follow driving led by some professional race drivers and no issues beyond the CEL light being on. Once the mini cats were installed and codes cleared never got those codes again in 2-3000 miles of use. That said I did get a random fuel lean code about 2500 miles in with an associated O2 code (not the same code that tripped with the race headers), cleared with the Cobb, and haven't seen it since so it's probably a good idea to have some sort of ability to clear codes in case you do get an occasional semi-expected CEL.

Short answer, you will probably trigger a CEL and it will not affect drivability.

 

I've got catless headers on the way with the Fabspeed mini-cats so will be interesting to see what happens. At some point I'll probably get a tune and it can fix that problem then, if it arises.

 

i have dundon race headers. roughly 5k miles and no cel light. i do track the car as well.

 

i will Echo Soul. I have the Soul race headers and they are fantastic. I am using the Vibrant 02 90 degree 02 spacers with the middle orifice adapter and i have had 0 cel for cats. I have run it on longest stretch for about 100 miles or about 2 hours and no cel or even 1 count of failure. Here is what i am using https://www.ebay.com/itm/23343562451...waArXaEALw_wcB

 

Agree. I had a CEL due to the post-cat O2 sensors and no issues.

 

with a Softronic tune. Scott has a CEL workaround file that works perfectly with Soul catless headers.