AMS catless downpipes install

[greentrbo95gst]

I finished my install today and took the car out for a drive. The car feels a little sluggish and I can't figure out why. It sounds much louder with the OEM exhaust and the cracks are very loud. I can also hear the turbo spooling much louder.

Any ideas on sluggishness?

[Used2be]

Originally Posted by greentrbo95gst

Any ideas on sluggishness?

Thanks for posting your pictures. Perhaps the DMEs are learning to deal with the change in O2 readings from the sensors? I think people have reported improved engine response with more miles driven. How was the secondary O2 cable stretch to connection if you used the stock wiring? Did you end up doing the install yourself, or have EAS do it?

[greentrbo95gst]

Originally Posted by Used2be

Thanks for posting your pictures. Perhaps the DMEs are learning to deal with the change in O2 readings from the sensors? I think people have reported improved engine response with more miles driven. How was the secondary O2 cable stretch to connection if you used the stock wiring? Did you end up doing the install yourself, or have EAS do it?

I did the install myself. It's a pain, but doable. The driver's side O2 cable fits ok when the plug is removed from the OEM bracket, but the passenger side is pretty bad. For that price they should include longer cables with the factory plug in my opinion.

The sound and cracking with OEM exhaust became much louder as well as the turbo spool.

[Tom C]

Originally Posted by greentrbo95gst

I did the install myself. It's a pain, but doable. The driver's side O2 cable fits ok when the plug is removed from the OEM bracket, but the passenger side is pretty bad. For that price they should include longer cables with the factory plug in my opinion.

The sound and cracking with OEM exhaust became much louder as well as the turbo spool.

Have you tried anything to prevent the CEL?

[greentrbo95gst]

Originally Posted by Tom C

Have you tried anything to prevent the CEL?

I wanted to try the o2 simulator along with the microcat together, but there is simply no room for them considering the 02 bung has been moved further down. If AMS used oem locations for the secondary o2's then it would be possible.
We all know that Microcats by themselves don't work.

[dhirm5]

Have others reported a similar performance drop after installing DPs? Everything I've read indicates that you should be seeing a gain of 30 - 40 whp..

[Tom C]

Originally Posted by greentrbo95gst

I wanted to try the o2 simulator along with the microcat together, but there is simply no room for them considering the 02 bung has been moved further down. If AMS used oem locations for the secondary o2's then it would be possible.
We all know that Microcats by themselves don't work.

That is complete BS that AMS couldn't place them in the OEM spot....especially since the OEM also has to deal with putting the catalytic converter in there as well...for the price they charge it should be perfect and come as a complete package with extensions....

I might just try and fabricate a downpipe myself with OEM locations for sensors....

[greentrbo95gst]

Originally Posted by dhirm5

Have others reported a similar performance drop after installing DPs? Everything I've read indicates that you should be seeing a gain of 30 - 40 whp..

I will drive it around a bit more and wait until the DME gets used to the change.

[greentrbo95gst]

Originally Posted by Tom C

That is complete BS that AMS couldn't place them in the OEM spot....especially since the OEM also has to deal with putting the catalytic converter in there as well...for the price they charge it should be perfect and come as a complete package with extensions....

I might just try and fabricate a downpipe myself with OEM locations for sensors....

Totally agree with you. Fitment wasn't excellent as you would think either.
Having the o2 bung in the oem location might fix two issues, CEL; if the o2 simulator work, and cable length for the o2.

[Used2be]

Originally Posted by greentrbo95gst

I wanted to try the o2 simulator along with the microcat together, but there is simply no room for them considering the 02 bung has been moved further down. If AMS used oem locations for the secondary o2's then it would be possible.

Thanks for your report, maybe that will be a winter project for me and I can take my time. I was hoping the stock exhaust would pick up with the cats out of the way. I might contact AMS to see if they will let me install the secondary O2 bung myself, in a location more conducive to using aftermarket devices. I wouldn't mind grinding the bung to a weldable shape on the curved portion of the DP. I wonder if AMS would consider positioning the secondary O2 bung up top in the catless DPs they build? With no cats the location is irrelevant and the cable connection would be simple. Just thinking out loud, but it seems like a viable option to me. Just took a look at the heat shielding, and that would be a problem with the secondary O2 bung up top.......darn!

[greentrbo95gst]

Originally Posted by Used2be

Thanks for your report, maybe that will be a winter project for me and I can take my time. I was hoping the stock exhaust would pick up with the cats out of the way. I might contact AMS to see if they will let me install the secondary O2 bung myself, in a location more conducive to using aftermarket devices. I wouldn't mind grinding the bung to a weldable shape on the curved portion of the DP. I wonder if AMS would consider positioning the secondary O2 bung up top in the catless DPs they build? With no cats the location is irrelevant and the cable connection would be simple. Just thinking out loud, but it seems like a viable option to me.

If you are in no rush that would be a great solution. I have access to a welder, but no skills to weld. I can wrench on the car, but can't fabricate anything.
You can probably put a o2 plug in the secondary slot and put another bung in the oem location.

[greentrbo95gst]

By the way, I used jack stands to do the work and did not remove any of the undertrays or support brackets underneath.
A lot of guys on here claimed the job was impossible without the lift, not true. I got couple tshirts dirty from being on the floor, but it's definitely doable.

[Used2be]

Originally Posted by greentrbo95gst

By the way, I used jack stands to do the work and did not remove any of the undertrays or support brackets underneath.

Great, it looks like the stock DPs are removed out the top, so no clearance problems to worry about dropping them out the bottom. It is tight in there though, I can see how it would be a pain to do. Did your small floor jack lift the car OK?

[greentrbo95gst]

Originally Posted by Used2be

Great, it looks like the stock DPs are removed out the top, so no clearance problems to worry about dropping them out the bottom. It is tight in there though, I can see how it would be a pain to do. Did your small floor jack lift the car OK?

My car sits on H&R's and I had to use my small floor jack on each side, put couple thick dictionaries under the front tires and then used a different floor jack to raise it from the center jack point.

It was definitely tight replacing the gaskets form the bottom, but it's doable.
Stock dp's come out the top and you drop in the new ones from the top as well.

Regarding your heatshield point: there are openings for the stock location secondary o2's. They should have just copied that and weld the bungs in there.

[AlphaAlpineM6]

How do you feel about the odor?

[RPiM5]

Can't wait to hear the Catless Downpipes with the stock OEM exhaust! Nice job dude.

As I told you, it takes about a tank of gas for the DME's to adjust or about 400-500 miles. I didn't actually feel any increase in performance until about the 700 mile mark on my downpipes, and yes my M5 felt sluggish as well, when I first installed them. The DME is in fact confused when you first put them on. I tried dyno'ing my M5 only 2 hours after I installed my downpipes, and the results on the dyno were extremely erratic. I came back 2 weeks and over a 1,000 miles later and my M5 was making a lot more power in the mid-range. Peak horsepower won't change with the downpipes installed, but peak torque will.


Also, FYI everybody. RPi should have their new GT Downpipes ready next week. They will have the O2 sensor locations in exactly the same position as the OEM sensors. Pricing should be about $1,500 before any discounts. RPi should be doing a group buy and they also honor military service with a discount as well.

Contact RPi for any questions you may have.

[greentrbo95gst]

Originally Posted by AlphaAlpineM6

How do you feel about the odor?

It's bad, but I just roll up the windows at a stop light.

[greentrbo95gst]

Originally Posted by RPiM5

Can't wait to hear the Catless Downpipes with the stock OEM exhaust! Nice job dude.

As I told you, it takes about a tank of gas for the DME's to adjust or about 400-500 miles. I didn't actually feel any increase in performance until about the 700 mile mark on my downpipes, and yes my M5 felt sluggish as well, when I first installed them. The DME is in fact confused when you first put them on. I tried dyno'ing my M5 only 2 hours after I installed my downpipes, and the results on the dyno were extremely erratic. I came back 2 weeks and over a 1,000 miles later and my M5 was making a lot more power in the mid-range. Peak horsepower won't change with the downpipes installed, but peak torque will.


Also, FYI everybody. RPi should have their new GT Downpipes ready next week. They will have the O2 sensor locations in exactly the same position as the OEM sensors. Pricing should be about $1,500 before any discounts. RPi should be doing a group buy and they also honor military service with a discount as well.

Contact RPi for any questions you may have.

Thanks Dave. I am having my buddy fix the exhaust leak today on a lift.
Nevermind, he just called and said he couldnt get the gaskets until Monday or Tuesday.
If RPI has a secondary sensor in the oem spot, I might be switching again.
Shoot, I should start offering downpipe installs as a side job.

I will keep you updated if I can get those gaskets early. Taking off to SF this weekend, but we can meet up next week if you are available.

[dhirm5]

Originally Posted by RPiM5

Also, FYI everybody. RPi should have their new GT Downpipes ready next week. They will have the O2 sensor locations in exactly the same position as the OEM sensors. Pricing should be about $1,500 before any discounts. RPi should be doing a group buy and they also honor military service with a discount as well.

Good news

[BarryB]

Originally Posted by greentrbo95gst

Thanks Dave. I am having my buddy fix the exhaust leak today on a lift.
Nevermind, he just called and said he couldnt get the gaskets until Monday or Tuesday.
If RPI has a secondary sensor in the oem spot, I might be switching again.
Shoot, I should start offering downpipe installs as a side job.

I will keep you updated if I can get those gaskets early. Taking off to SF this weekend, but we can meet up next week if you are available.

I'll be in the wine country with my F10 this wkd. Let me know if you will be up there to meet......

[greentrbo95gst]

Originally Posted by BarryB

I'll be in the wine country with my F10 this wkd. Let me know if you will be up there to meet......

We are flying and driving my e46 there. Wedding stuff to do. ..

[greentrbo95gst]

300 miles and no CEL.... I am driving the car like I stole it.