How to gut your primary cats (Dyno results to come soon)
#181
Has anybody had any luck with a mechanical O2 simulator on the IS-F? My friend who owns a performance shop said the trick with these Lexus/Toyota's is to use steel wool inside the mechanical O2 sims for them to work. They are much more finicky than other makes.
#182
Sure but it would be about 10x more work. Jacking the car up and un bolting the exhaust takes more time than the actual gutting of the cats.
Cutting them off and welding a pipe on will take a lot more time and effort not to mention significantly more money.
#183
Thanks for the answer Sylvan. So this will prolly come out as a silly question, but how exactly are people gutting the cats and not damaging the o2 sensor as you would be beating the cat debris towards it correct?
#184
Just go easy on it, I use a hole saw on a drill to get started and a long drill bit and work it around. You can pound with a flat screw driver as well. The cat material is not hard at all it breaks up really easy and is super dusty so a dust mask is also a good idea.
#185
ive been to the track a few times now and have been consistently running between 12.39-12.5 with gutted cats and borla exhaust with upsized tires (275). I'm installing PPE headers within the next week and will be making another trip up to New England drag way. I'm hoping that I'll break into the 12.2's with headers. To my knowledge I don't think someone has done a comparison like this yet. I'm looking forward to the results.
#186
Unfortunately they closed mid October for the winter... The butt dyno tells me it feels a little better in low to mid range but I'm so used to it now it's difficult to recall what it was like before. Sorry I wish I had more definitive results but in my honest opinion I dont think the gains from headers are worth the $$ over gutted cats.. Hopefully that's only because of a tuning issue. I'm hopeful we'll have an answer to that question in the near future.
#188
#189
Yes here in Dubai - abudhabi
we do not have problems with catalyst
any shop can do them
i just wanted to know if someone have pics of putting straigh pipes in !
or any tips for giving the shop for doing that
we do not have problems with catalyst
any shop can do them
i just wanted to know if someone have pics of putting straigh pipes in !
or any tips for giving the shop for doing that
#190
You can go to a shop and check if they can do it. I don't think they'll be able to without removing the headers because the space is very limited.
#192
If you plan on reflashing your ecu, you will probably not need either of the o2 sims/conditioner.
#194
Sawing off the catalytic converters and replacing them with straight tubes of the correct diameter will actually improve performance over gutting the cats. Stuffing a tube in the gutted cat nearly the same diameter as the inlet and exhaust from the cat will yield similar benefits.
The bulge from the cat's empty shell will slow velocity and increase heat loss. It's a lot of why headers are still slightly better than gutted cats. But if you can cut the cats out and replace them with the right sized tubing, you'll be 98% of the way to header performance.
The bulge from the cat's empty shell will slow velocity and increase heat loss. It's a lot of why headers are still slightly better than gutted cats. But if you can cut the cats out and replace them with the right sized tubing, you'll be 98% of the way to header performance.
#195
Interesting advice, didn't think beyond gutting the primaries that it would have any additional benefit to replacing them with straight tubes of the correct diameter (assuming that's 2.5"?).
In your opinion would it be hard for a muffler shop to cut and weld in straight tubes without damaging the sensors upstream?? Because if this will allow the stock manifolds to come closer to aftermarket headers then this might be a viable option for many that don't want to spend the money on headers & install and if they can get a little better flow vs just gutting them then I think more owners might go this route!
In your opinion would it be hard for a muffler shop to cut and weld in straight tubes without damaging the sensors upstream?? Because if this will allow the stock manifolds to come closer to aftermarket headers then this might be a viable option for many that don't want to spend the money on headers & install and if they can get a little better flow vs just gutting them then I think more owners might go this route!