GR Yaris HJS Downpipe with ECE-approval
- Thread starter Andy R
- Start date
Another data point here, HJS cat and OPF delete MOT pass
Hello! I’m getting a HJS Downpipe for GRY 2025 gen 2 automatic. Can you explain what fitting problems people had? The store that sells it says that they wait for a solution for this problem (from a technician):
HJS-Nr. 90 81 80 15 has Ø 110/60mm and my Milltek Pipe Diameter: 3.00-inch (76.20mm).
HJS-Nr. 90 81 80 15 has Ø 110/60mm and my Milltek Pipe Diameter: 3.00-inch (76.20mm).
speeddemon666
Dedicated member
- May 24, 2025
- 141
- 124
- 43
I was looking to fit a sports cat to my gen2 with an after market exhaust. Are there currently reasons this cannot be done?
The outlet on the OEM cat/downpipe is also 60mm, the HJS is a drop in replacement - so no benefit from a 3in GPD/backbox other than noise!
The RM motors downpipe is 4inch to 3inch, so better flow, but you can't use it with the OEM size GPF pipe. Coincidentally I will be selling mine (with euro6 sports cat in the GPF pipe) shortly as I went big turbo
The RM motors downpipe is 4inch to 3inch, so better flow, but you can't use it with the OEM size GPF pipe. Coincidentally I will be selling mine (with euro6 sports cat in the GPF pipe) shortly as I went big turbo
U say it’s useless the HJS ?The outlet on the OEM cat/downpipe is also 60mm, the HJS is a drop in replacement - so no benefit from a 3in GPD/backbox other than noise!
The RM motors downpipe is 4inch to 3inch, so better flow, but you can't use it with the OEM size GPF pipe. Coincidentally I will be selling mine (with euro6 sports cat in the GPF pipe) shortly as I went big turbo
It can be done, i have a confirmation now that it’s plug and play. I want to see if there are benefits in replacing the oem downpipe, see the upper answer .
No not at all, the HJS is more free flowing than the OEM for sure.
Cars equipped with the HJS typically Dyno at least 10hp higher
