DIY: Installing a remote controlled valved exhaust on a pre-LP640

The Fabspeed LP640 high-flow cats with vacuum dump off valves arrived today, so the install officially kicked off this evening.

 

After round 1, I can say that the majority of the potential show stoppers have been overcome:

-Will I be able to get the clamps off the primaries?

-Will the old primaries come out without having to disassemble a lot of things, or have to raise the car higher than I can with my jacks/stands?

-Will the new primaries be able to fit in without problems even though they are thinner, but they are much longer than the non-LP640?

-Will there be any interference for the valves from the sway bar, parking brake, or frame?

-Will everything line up with the new tips and the stock muffler since it's all designed for an LP640 not a series 1 Murci?

 

So far everything looks good. But I won’t know for sure on the final point of alignment until I am able to reassemble everything tomorrow.

 

Getting out the primaries went pretty well thanks to Ty who gave me some pointers since he recently replaced his primaries in his garage.

 

The trick on both sides of the primaries is to remove the one nut from the clamps that is easy to get to, then spray the entire clamp with lubricant, and then take a long bar with a hammer to bang the clamp around until it turns enough to be able to get a wrench or socket on the other nut.

 

Once the clamp is off, the passenger's side primary comes out with only needing to pull off the vent hose to the alternator -- after you remove the thermocoupler and disconnect the O2 sensor cables. You do not need to remove the O2 sensors to get out the primaries. You can do that later on the bench.

 

The driver’s side primary comes out with only removing the carbon fiber panels so you can get to the pre-cat O2 sensor connector that is weaved through the frame. The other 3 are easy, but this one is a bit of an effort to thread the connector back through the frame and the other cables in the way. Getting the driver’s side primary out is a little bit of a Chinese puzzle compared to the passenger side. I found it best to pull it toward the back and then toward the center and rotate it out.

 

It’s great that you don’t even need to remove the sway bar to get out the primaries or any other big effort on the early Murci. But if you did, removing the sway bar is an easy thing to do on this car, and this would give you a lot more room to work them out.

 

The new ones slide right in because they are much thinner than the old ones and give plenty of wiggle room.

 

I am taking the day off from work tomorrow to finish the project, assuming there are no big surprises on the alignment that will cause a big delay.

 

I still need to sort out switched 12v for the vacuum remote in the engine bay, and I also need to find a way to connect the chassis ground wires to the new primaries that don’t have a mount. I think I can put them on the mount for the vacuum valves that have screws holding them on.

Thank you for the accurate DIY. Masterpiece!

I ordered the exact same fabspeed deletes with valves, as well as a remote valve controller for my LP640. Thanks for the DIY. Very interested in your installation, so please keep me updated with the valve controller wiring and such!

 

Thanks!!

It's too late for me to do the big write up with pics, but the good news is that it worked!

 

Here's a teaser.

 

It's too late for me to do the big write up with pics, but the good news is that it worked!

 

Here's a teaser.

 

those pipes look good.... i bought the larini exhaust of the same guy on ebay- missed out on the pipes as you bought them LOL

It’s taken me a while to update this thread, but I did get everything done a week ago, and it all went to plan. The Fabspeed LP640 sport cats with valves, OEM secondary cat bypass, OEM huge muffler, Larini LP640 tips, and key fob vacuum controller all went in with none of the anticipated fit issues.

 

There have been no codes after driving for a week, so no issues with the temp sensors or O2 sensors, which is great.

 

Overall, a massive success based on getting 4 different manufacturers products to fit and function in an earlier version of the Murci.

 

But, I would have to say it’s a failure on sound – so far because this is not over yet.

 

For sound, I was hoping for stock quiet vs. nasty loud. The current result is that the quiet setting sounds a little throatier with the sport cats, and when the valves are open, it’s louder, but not dramatically louder.

 

There is no drone at all in either setting which is great, but as it stands, it’s not worth closing the valves because the sound in the cabin is almost unchanged, and on the outside, the sound is mild unless you are really gunning it.

 

I believe the reduced sound boils down to the fact that when the valves are open, they open a new path for the exhaust to go straight to the tips, but they don’t block off the path through the muffler, and the two paths meet up before the tips.

 

To test this theory, I put in blanking plates between the muffler and the secondary cat deletes for a short test. And the result was a louder raspier sound (see videos). But still not that much louder, which I still believe the extra volume for the exhaust to travel and come back to meet at the tips is causing it to be quiet.

 

So my next experiment will be to put back on the stock tips that don’t have the extra branch to meet up with the dump valves, and temporarily let the dump valves exhaust straight out for sound testing. If that gives great results, then I will have the extra branch on the Larini tips removed and have small tailpipes made up to dump the extra exhaust safely when the valves are opened.

 

I may also test putting back the Larini tips and installing the LOC x-pipe in place of the OEM muffler, and see how that sounds will all the extra plumbing, just out of curiosity.

 

Some notes on the final installation:

 

- I found a spare wiring connector that was capped by the right rear behind the blue vacuum reservoir that just happens to be switched power that I could use for the vacuum controller. The vacuum control only needs .3 amps at 12v as the highest input, so this feed works just fine.

- I was able to install a T-fitting for the vacuum source by cutting a little bit of the 1/2 inch hose coming out of the vacuum reservoir and installing a vacuum T in the kit.

- I mounted the control box to the top of the air cleaner cover since that cover is behind the carbon fiber, and it's always being fed with cool outside air

- I found it's easiest to use the v-clamps from the Fabspeed kit by taping the t-shape threaded rod to the v-clamp, or it will constantly pop out. I also used a tie wrap to hold the clamp together so I could work it with one hand, and tighten the tie wrap so I could get a nut onto the threaded end. Would have been very difficult otherwise

- Don't tighten the v-clamp for the primaries to the manifold too tight or heat expansion will cause it to move and put the tips out of place. It shouldn't be loose, but just not too crazy tight.

 

And here are the videos of the sound both with the valves as normal being open and closed, and with the blanking plug for the exhaust.

 

https://www.youtube.com/watch?v=r4dit9divb8

 

https://www.youtube.com/watch?v=wjVV7ekv9O4

 

https://www.youtube.com/watch?v=9DVVWpF0NH4

 

https://www.youtube.com/watch?v=AZmZirX8m5A

 

 

Very cool!

How much would a shop to charge to do something like this (parts/labor)?

Nice write up!

 

I think the reason there is no drone and not-nasty loud noise is the fact you still have cats. So the system is going to be similar to a muffler delete system, but the Fabspeed cats are going to be louder and flow better than the factory cats.

Very cool!

How much would a shop to charge to do something like this (parts/labor)?

 

Good question. I would say for an experienced Murci mechanic that's changed a number of exhausts on this car, they can probably do it in 4-6 hours. But that probably won't stop them from charging 10-20 hours.

 

Normal rates are around $125 to $150 for independents around here. So anywhere from $500 to $3000 for such an install...

 

 

Ok, I removed the Larini tips and put back on the stock tips so that the valves dump straight into the air, and not into the tips to mix with the exhaust flow from the muffler.

 

It's a lot louder than before. Loud enough that the valves being open/closed make a big difference now.

 

https://youtu.be/_9VvcXR970U

 

 

So my plan now is to modify the Larini tips to be non-LP640 tips. That means that I would have the extra branch removed so that it only has pipes going to the stock muffler. I think this mod will actually make these slash cut 4.5" Larini tips more valuable because the market is bigger for this style of tips with the non-LP crowd. The LP crowd already has a cool looking big exhaust tip.

 

That will leave room to make a second set of hidden exhaust tips that would direct the flow from the primary cats bypass valves down between the Larini tips.

 

Exhaust is always allowed to flow through the muffler since the valves only open up the bypass, but don't close off the muffler route, so the end result is that exhaust is always coming out the Larini tips, even when the valves are opened.

 

I am talking to Fabspeed about these extra "down pipe" exhaust tips because something would need to be fabricated. Something along the lines of this crude annotation.

 

So my plan now is to modify the Larini tips to be non-LP640 tips. That means that I would have the extra branch removed so that it only has pipes going to the stock muffler. I think this mod will actually make these slash cut 4.5" Larini tips more valuable because the market is bigger for this style of tips with the non-LP crowd. The LP crowd already has a cool looking big exhaust tip.

 

That will leave room to make a second set of hidden exhaust tips that would direct the flow from the primary cats bypass valves down between the Larini tips.

 

Exhaust is always allowed to flow through the muffler since the valves only open up the bypass, but don't close off the muffler route, so the end result is that exhaust is always coming out the Larini tips, even when the valves are opened.

 

I am talking to Fabspeed about these extra "down pipe" exhaust tips because something would need to be fabricated. Something along the lines of this crude annotation.

 

why not just add extra valves to close of the muffler flow totally?

 

or

 

try my exhaust tips- LP640 end, single pipe entry (like what you plan). I'll post up a pic tomorrow. You can have the tips, and I'd pay you what you paid for yours

 

Another cool system would be primary cat delete then bypass to straight pipe or up through secondary cats into sport exhaust. Valve closed you'd have cats and muffler, bypass would be straight pipe throughout

why not just add extra valves to close of the muffler flow totally?

 

or

 

try my exhaust tips- LP640 end, single pipe entry (like what you plan). I'll post up a pic tomorrow. You can have the tips, and I'd pay you what you paid for yours

 

It's a good question and an option I researched. It's easy to buy 2.5" valves that are closed with no vacuum, which is opposite of the primary valves.

 

But 2 issues:

 

- The primaries with valves never were designed to put the entire exhaust flow through the bypass. Instead of enhancing the flow with the valves opened (Lambo's plan), you would be restricting the flow and adding back pressure if you closed off the muffler.

 

- While the sound is louder by blocking off the muffler, in person, it's no where near as loud as dumping the exhaust out from the primaries while leaving the muffler route open. The whole point of the remote controlled valves is to have a big difference between open and closed, or you might as well skip the valves.

Another cool system would be primary cat delete then bypass to straight pipe or up through secondary cats into sport exhaust. Valve closed you'd have cats and muffler, bypass would be straight pipe throughout

 

Knowing what I know now, I would probably go with the primary cat bypass with valves instead of a sport cat. But if I tried that, I might find that it's not much louder than the sport cats since the sport cats are supposed to flow well.

 

And it's not clear if I would like the sound better or worse. Maybe the sport cats refine the sound without making it quieter. Who knows!

 

It's cost prohibitive for me to keep trying all these options, but I am curious.

Big day today.

 

I finally got the nerve up to take the Larini LP640 tips to a nearby muffler shop to have the extra branch amputated, which will open up the path to run a second set of hidden exhaust tips that will turn the bypass valves into dump valves.

 

For the past week, I have been driving around with the original tips in place to test how I like the dump valves, and it's definitely the way to go. So I did it.

 

The muffler shop did a great job of cutting off the branch without adding any restriction, and while it's not as pretty as the original pipes, the surgery is completely hidden from view.

 

I do believe cutting off the branch actually makes these tips more desireable because not many LP640 owners seem to want to switch from their big single exhaust tip to 2 tips. And now that the branch is gone, these tips look and work great with the 02-06.

 

Also, cutting off the branch had an additional benefit of giving my tips more wiggle room to increase the distance from the bumper heat shield. With the branch, it was very close to the heat shield and couldn't be moved down because of the solid link to the bypass branch and the bypass' connection to the secondary cat deletes.

 

I had the muffler shop save the flange that was cut off, and I have some flexible 2.5" exhaust tubing coming tomorrow to work on the best way to dump the exhaust safely away from the chassis and bumper. At least now I can see there is a clear path to add these hidden tips, which is great because I was worried about the amount of space until I could see with these modified tips on there.

Final update because the project is now complete!

 

I had the last piece of the puzzle, the dump valve tips, fabricated this week. These new tips are invisible from behind the car, which is great. You only see them if you crawl under the car, but they do an excellent job of keeping the exhaust away from the chassis and bumper when the dump valves are open.

 

Now I have my loud and quiet settings all working at a push of a button. The loud setting is not obnoxiously loud from the inside the cabin, but it's nice to be able to switch to the quiet settings for the neighbors benefit and when I need to talk on the phone or to the passenger.

Here's a video of the cars leaving the Ride n' Shine event this last weekend. You can hear my car with the valves open in this video:

 

 

It's definitely more of an old school V12 sound than the high pitched F1 sound, which I think goes well with the more conservative styling of the 1st Gen.

Here's an on board video of just driving around this evening.

 

https://youtu.be/nMgOB9EjNmM

 

One thing I like about the dump valves is that they vent below the bumper which really cuts down on the heat put into in the muffler system and should make those nearby body parts and paint last longer.

That sounds good.

 

FYI, 2:20 mark for the flyby video (with a Huracan immediately after.)

That sounds good.

 

FYI, 2:20 mark for the flyby video (with a Huracan immediately after.)

 

 

Thanks!

 

This might be a more reliable link for automatically starting the video at 2:18 when the Murci first emerges. That last link is iffy and starts at the beginning sometimes:

 

Very useful write up from a great guy. Can't wait to hear the new tweaks.