3rd Cat Delete and Valve Controller Opinion

[SuperchargedLotus]

Given there are several purchase options in terms of the 3rd cat delete, is there a particular one that is having this issue with having to expand the pipe, and are there others that fit straight away?

After reading this forum it seemed that the GRP one required adjustment so I went for the Milltek…. It fit straight on without any adjustment needed.

 

[EZcheezy]

What is the impact of 3rd Cat delete on warranty? Anyone have any dealer pushback?

I did have push back. I got a check engine light 4 months after owning the car while I had the 3rd cat delete + valve controller. it ended up being a bad battery but I still had lots of back and forth with the dealer with them telling me i needed to revert it back to stock before they could diagnose. Lotus was forcing them to.

after a few days of arguing they agreed to fix it. im still unclear on exactly what happened but it sounds like I was right on the border, any more mods and i will probably have to revert it back to stock for any more warranty work.

they fixed my battery but broke the valve controller. it seems to be stuck on open for now.

then a week later I installed the GRP intake

 

[Tod]

I just spent quite a bit of time in my car (factory) and a friends who just did the 3rd Cat and Valve controller.. My opinion might be a little different..

1. When you are ON the gas in any gear, it sounds AMAZING.. with the valves 100% open in Sport mode.
2. When you are just cruising around in Sport mode and valves 100% open and between 2500 - 3500 rpms is doesn't sound much different than in sport mode without the 3rd cat and VC installed.
3. Revving the car sounds absolutely intoxicating.. It now sounds like it looks.

I love that his car can be put into various modes where you can choose what you want to hear. You need quiet, put it in OEM mode on the VC and Tour Mode on the car and it sounds pretty damn close to stock in Tour Mode. Want a little grumble put it in Sport with VC in OEM.. Nice and just a little better than regular sports mode with no VC or 3rd cat. Want a bit more grumble and burbles, yep they got that too.. Tour mode with 100% open on the VC. Want it to sound like a V8 with aftermarket exhaust (IMO) then Sport Mode (or Track) and 100% open on the valves.. It so good when you are on the gas..

Again this is my opinion and your mileage might vary..

Hope this helps someone decide.

Ryan G

This is helpful information. I had a 3rd cat delete and installed the Miltek valve controller. I was not aware that with these adjustments, and when in different modes, Tour, Sport or Track that the sound would provide more amplification and burbles.

 

[RobR]

After reading this forum it seemed that the GRP one required adjustment so I went for the Milltek…. It fit straight on without any adjustment needed.

Is there consensus here on the Milltek being a fit out of the box vs. GRP? Seems there are four options: Milltek, Larini, Aerie, and GRP. There seems to be no opinions on Larini fitment and GRP seems to require a pipe expander for installation. So, in a nutshell, is Milltek the best option?

 

[chirowolf]

After reading this forum it seemed that the GRP one required adjustment so I went for the Milltek…. It fit straight on without any adjustment needed.

I just did mine and used the GRP. It was a bit loose, so I went to a local shop and they "bumped up" the diameter a hair. The shop did not even charge me. Took them literally 2 minutes for the job.
The shop said I could have used a little exhaust cement (did know this was a thing) if I did not want to expand the pipe. The shop said to be careful expanding stainless because it tents to rip. After the shop expanded the pipe, it fit nice and snug.

 

[Brokenblinker]

I just got through most of the install of my GRP pipe last night too. It was a little bit loose, and I figured I would just try and continue and bolt things up. After everything was bolted up tight, and the clamp was cinched as tight as it can go, the pipe was still quite loose.

I decided to take everything back apart and get a pipe expander and I'm doing that today.

 

[EZcheezy]

GRP pipe requires a new ring too dont forget. the others might too, cant say for sure but i would assume so

Lotus Emira Exhaust Ring Gasket

Replacement exhaust gasket for between the three bolt connection at the midpipe and third cat connection on all 2023+ Lotus Emira V6 Cars. A good idea to have on hand if you are installing one of our third cat delete pipes! This is an aftermarket Felpro graphite type gasket.

www.gregsraceparts.com

 

[chirowolf]

GRP pipe requires a new ring too dont forget. the others might too, cant say for sure but i would assume so

Lotus Emira Exhaust Ring Gasket

Replacement exhaust gasket for between the three bolt connection at the midpipe and third cat connection on all 2023+ Lotus Emira V6 Cars. A good idea to have on hand if you are installing one of our third cat delete pipes! This is an aftermarket Felpro graphite type gasket.

www.gregsraceparts.com

not sure what Lotus uses for gasket rings but it appears to be some kind of braided metal. Mine was toast and was happy to replace it

 

[Brokenblinker]

I mushed one down as a test fit, but now I'm deciding to expand the other end of the test pipe a little bit.

Now I need to debate whether to go back and replace the gasket again.

 

[scc.131.fe]

FWIW my GRP pipe was a good fit outta the box.

 

[netsinah]

When installing the GRP third cat delete, my OEM Lotus exhaust gasket (a braided material) needed replacement, after only about 2,500 miles (4,000 km). See photo below, of both the old and the new Fel-Pro replacement I purchased from GRP. The old one likely fractured in the one area, during removal. I'd suggest always having a replacement handy, given its low cost of about 10 bucks.

The new pipe went in w/o much problem, which suggested it wasn't properly sized, since the Forum install directions said you were "lucky" if it was a difficult fit and you had to repeatedly/slowly wriggle it in. Regardless, I checked the fit and didn't see any gaps. But to be safe, I then applied an exhaust sealant around the joint. It was a challenge reaching around the entire joint, since part of it wasn't that accessible. I now wish I had applied the sealant on the new pipe, before install, to better ensure the sealant made it everywhere. Anyway, I ++ tried to apply sealant everywhere, by reaching around as best I could, to get to the hard-to-reach area.

For sealant, there are several available. I went with the "VersaChem exhaust joint and crack sealer". Others use the "J-B Weld" sealant. They come with different heat ratings but this area isn't exposed to extreme heat, so I didn't think it necessary to pay a premium price for the higher heat rated sealants.

You may wish to use a sealant, even if your pipe joint fits really tight, just in case. Hope this helps and good luck to all those doing this mod.

 

[Brokenblinker]

How strong are the sealants if you ever plan to go back and restore the stock cat? Does that make it significantly harder?