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Discussion Starter · #1 ·
Hello All,

After reading for years about Record Monza valve reliability and wondering about the very tight spring it comes with, I decided to get serious and understand this valve.

The thread that inspired my thinking was this one:


Anyways, I bought a brand new Record Monza exhaust for my 2018 Lusso a few years ago. It was shiny and new and seemed great. Initially, it was too quiet which was quickly solved with deleting the midpipe resonator that comes stock on the Classica/Lusso, but is not installed on the Abarth models. Perfect. Now I had a Lusso that sounds like an Abarth.

After 2 years of driving and diligently maintaining the valve with anti-seize and doing all the things people say to keep it working, I started to wonder if it was working at all. That spring really is quite tight and tough to stretch. So, I removed the spring and put a lighter spring on.

Result: No change to the sound, regardless of engine load compared to the brand new Record Monza

So, I put a ridiculously light spring on and tried again.

Result: Again, no change to the sound, regardless of engine load compared to the brand new Record Monza

So I took the spring off and ran the car with the valve free to go wherever it wanted

Result: A totally different bark that I had NEVER heard in the previous 2 years of ownership.
Conclusion: That valve has NEVER opened under every condition of driving in the past 2 years.

So the solution seems simple, take the spring off - only then the valve rattles and makes junky sounding noises at certain RPM's - and that's just not acceptable. So, I wired the valve open with some metal wire.

Result: No more rattle, but now the exhaust was always in louder mode.

So, this could work, but why have a valve that can move if it's going to stay closed all the time (as it comes from the factory, at least in my case) or stay wired open all the time. That seems silly given someone took the time to engineer this beautiful and crazy instrument of an exhaust.



So, I decided to get serious and take an active control approach to the Record Monza valve. There are active exhaust cutouts that people run and some cars, stock, have active exhaust systems. I wondered if I could retrofit this concept to my Record Monza.

So, here is a picture of the prototype:

Automotive tire Hood Automotive design Motor vehicle Bumper


I welded a boost actuated exhaust cutout actuator onto the top of my Record Monza exhaust and with a little creative use of nuts, bolts and standoffs, was able to create a linkage that actuated the valve stem through the correct angle range.

Here is it working for the first time:

VIDEO: Video of Valve Actuator

So now that I had something that was actuating the valve, I needed a way to control it. What I did was I tee'd off the boost line under the hood, where most people connect a boost gauge and rand a hose to the back of the car. This worked to open the valve upon high boost and finally gave me the "Roar when floored, but calm when not" demeanor I expected from this system when I bought it.

Automotive fuel system Motor vehicle Automotive design Automotive exterior Auto part



There was one catch to this setup. As soon as you come off the throttle, the boost line goes to vacuum and the valve closes instantly - sometimes before you get the pop of unburned fuel to ignite in the exhaust under just the right conditions. This means, that the pops are still muffled like they originally were, even though everything else was not as muffled under WOT.

I fixed this problem with a device called a speed control valve which is used a lot in the pneumatics industry. It's a check valve one way (to get boost to the actuator ASAP), but an adjustable needle valve the other way (which controls how fast any boost on the actuator side of the valve is bled off when the boost goes away). See the photo below. Youc an see the needle valve adjustment screw at the bottom of the black plastic valve assembly:

Hood Motor vehicle Automotive design Automotive fuel system Automotive exterior



Adding this valve made all the difference, as the Record Monza now stays open for a second or so after a hard shift.

Also, the progression to the loud setting on the record monza is just perfect to my mind now.

Check the video of a go-pro strapped under my car under various types of driving. You can see the valve stay closed until the boost builds, and it slowly returns after boost goes away.

VIDEO: On - Road Test of the valve system

I hope this info helps. I just wanted to do something unique to my car that makes it work more the way it was originally intended. I find it amazing that the Record Monza is built with such a crazy design that actually does not work at least in the case of my exhaust and some others on this forum (maybe some of them do work correctly, I just know for a fact that mine did not.) I chalk the original beauty of the design combined with the lack of functioning of the design to the "delightfully Italian part" of owning these cars :)
 

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2018 124 Spider Abarth Custom
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Wow, very nice work and idea! I just received a Ragazzon Electronic controlled valved exhaust for my Giulia and thought maybe you were putting the electric solenoids on. This is thinking outside the box and the kind of person I want on my team all the time.

Well done!!
 
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Extremely well done, I had this idea for my RM exhaust but was leaning towards using an electronic controller. This is just plain cool.


The T you have connected to the intake manifold and AOS - where did you find that? I still have my stock hard line that I wanted to re-use but couldn't find an appropriate tee.
 

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Discussion Starter · #5 ·
Extremely well done, I had this idea for my RM exhaust but was leaning towards using an electronic controller. This is just plain cool.


The T you have connected to the intake manifold and AOS - where did you find that? I still have my stock hard line that I wanted to re-use but couldn't find an appropriate tee.
I ended up removing the original hard line and bending some 3/8" stainless instrumentation tubing and connecting a 3/8' "prestolock" tee like one of these:

Tee Fittings

I don't think it's easy to find something that will go on the original hard line since it is a weird plastic-wrapped metal tube of some description.
 

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The spring make the same thing without need of get that line pressurized, which means more lag... sorry but I think in that way it's a downgrade, but fully functional and kind of less failure... but still not better performance! The spring engineering is perfect!!! If they had made the valve in stainless steel maybe they had developed one of the most better solution's for valved car exhausts....
 

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Discussion Starter · #9 ·
The spring make the same thing without need of get that line pressurized, which means more lag... sorry but I think in that way it's a downgrade, but fully functional and kind of less failure... but still not better performance! The spring engineering is perfect!!! If they had made the valve in stainless steel maybe they had developed one of the most better solution's for valved car exhausts....
That may be for your exhaust, but I can guarantee that the way mine was built, it was not working at all with the spring and I'm sure there are others with this same problem.

Agreed that there will be a very slight addition of volume of air that needs to be pressurized by the turbo, but it's a really small air line and the additional lag (if it's even measurable) is not noticeable at all.

I wasn't after top performance with this change - I drive my car for the fun, the experience, the sound...and in that respect, this change made the car a lot more enjoyable to go for a spin in. It added character, and didn't take away any performance that I noticed. It's all about getting the sound and hearing the engine tone change as the boost comes up while enjoying the sun :)
 

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Discussion Starter · #11 ·
It's guys like you that make this country great! Awesome work and shame on the manufacturer.
Thanks! Though I am a Canadian...But it's a pretty great continent you and I live on :)

I agree I just can't figure out why they would take the time to make such a complex exhaust system with complex welding and manufacturing jigs required, only to not have it function properly. Arguably, the other way to do this is to just delete the valve altogether and have a "fixed mix" of exhaust gasses spread amongst the 4 outlet pipes. As it is, it baffles me.
 

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Thanks! Though I am a Canadian...But it's a pretty great continent you and I live on :)

I agree I just can't figure out why they would take the time to make such a complex exhaust system with complex welding and manufacturing jigs required, only to not have it function properly. Arguably, the other way to do this is to just delete the valve altogether and have a "fixed mix" of exhaust gasses spread amongst the 4 outlet pipes. As it is, it baffles me.
Damn, You're the best argument for open borders yet. As for the exhaust. It's crap. As for your fix. Awesome, I think you should start manufacturing exhausts yourself. it's not that big a step past what you've already done.
 
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