Exhaust Valve Control Mod (how to)

namaste

Member
Messages
212
A little while ago I realised my exhaust valves were stuck shut and after getting them working again, I wondered if there was a simple way to open the valves manually via a switch installed in the cabin or something. I was thinking of something along the lines of controlling the Maserati vacuum solenoid under the hood but it looked far too complicated because it apparently operates on varying voltages and would throw up error codes if meddled with. So I thought all was lost but Catman explained the simple idea of installing a standard 12v vacuum solenoid between the Maserati vacuum solenoid and the exhaust actuators on the tailpipes and simply control that on and off. This would avoid any error codes and run off a simple 0v/12v control.

So I eventually got round to doing it today. A bit of a pain getting under the front of the car to take photos of the pipes, but all in all an easy and very cheap mod for anyone who wants to have their exhaust valves open at the touch of a button. This mod allows you to have the exhaust valves open even when out of sport mode should you want the soft ride but the loud noise. But also switches back to standard operation with the press of another button. So here's the how to for anyone interested:


This is the main pieces you need. A mini piggy back fuse holder for an easy 12v feed out of the fuse box (£2.50 off ebay). A 12v vaccum solenoid (£6 off ebay 2nd hand). It was listed as a bmw exhaust solenoid and is bascially identical in shape to the Maserati one on the car. A 12v remote controlled relay (£5.50 off ebay). A bit tricky to understand the instructions but figured it out eventually. This isn't all you need, you'll also want some vacuum pipe, cables, crimps, heat shrink, etc.

IMG_20170421_135421.jpg


Here's a view under the car once the front cover below the bumper is removed. The red arrow is pointing to the pipe you want to intercept. This pipe leads to the actuators in the tailpipes.

IMG_20170522_163049.jpg


Wasn't really any obvious place to put the solenoid down by the original so decided to place it up top and feed the vacuum pipes down. Found a handy tie wrap there that wasn't doing anything much so clamped it down using that.

IMG_20170522_195447.jpg


Fed the cables round the front. Obviously all this will be under the covers when they go back on.

IMG_20170522_195457.jpg


The remote relay fit nicely in the fuse box with just a couple of wires exiting through whatever gap I could get them through. I piggy backed off the fuse for the 'air conditioning compressor relay' according to the manual.
EDIT: Avoid piggy backing off this fuse as it means the control only works if the air-conditioning unit is on. It was the only fuse I could get onto with the piggy back fuse holder. I've ordered a mini piggy back fuse holder to piggy back off one of the smaller fuses towards the front of the fuse box. These have a 12v supply when the iginition is switched on and 0v when switched off, so are much more appropriate to use.

IMG_20170522_195509.jpg


And the outcome is it works perfectly. Start the car, press 'off' on the remote control and it opens the exhaust valves at all revs, regardless of being in sport mode or not. Push 'on' and it returns to standard operation, in my case on the GTS auto, closed at all times out of sports mode, and open above 3000rpm when in sports mode. And what a noise. I don't know how you put up with it all the time on the MC shift. It seems louder at lower revs than it does above 3000rpm. But I do love all the pops and crackles when you lift off when low down the rev range. But its proper asbo noise when driving around residential streets.
 

StuartW

Member
Messages
9,306
Well done & a good, simple to follow explanation too. I hope that you go one enjoying the results
 

namaste

Member
Messages
212
Well done :) Looks very similar to my install.

Really happy it's worked out for you

C

Thanks C!

Well done & a good, simple to follow explanation too. I hope that you go one enjoying the results

It certainly brings a smile to the face, and turns a lot of heads. This exhaust valve system exists on a lot of cars so the guide may be of help to people other than Maserati owners if Google picks it up.
 

bigbob

Member
Messages
8,952
Nice read, not sure I could do it but you make it look easy.

Can I ask exactly where the Maserati solenoid is in the engine bay?
 

namaste

Member
Messages
212
Nice read, not sure I could do it but you make it look easy.

Can I ask exactly where the Maserati solenoid is in the engine bay?

Sure, its down this gap arrowed. You can just about see the vacuum pipes and half the solenoid from the top with a torch, but to access the pipes you really need to get underneath and remove the cover on the bottom of the bumper.

EDIT: This isn't the location of the factory exhaust solenoid, it is in fact down by the tailpipes somewhere. The arrow here points to where the vacuum valves are located shown in the image in the first post of this thread.

IMG_20170522_195457.jpg
 

azapa

Member
Messages
1,300
great job and well explained! I would quite like to have the "race" sound in my car, but without the rest of the tension of being in race mode. I also use exactly one of those ebay 12V remotes to open my garage door, and it is always with me in the car, with spare buttons. The question is can I train (learn, I think they call it) one remote to two receivers. I think they use a rolling security code, so fear not.

do you have a part number (BMW) for that vacuum valve?
 

namaste

Member
Messages
212
great job and well explained! I would quite like to have the "race" sound in my car, but without the rest of the tension of being in race mode. I also use exactly one of those ebay 12V remotes to open my garage door, and it is always with me in the car, with spare buttons. The question is can I train (learn, I think they call it) one remote to two receivers. I think they use a rolling security code, so fear not.

do you have a part number (BMW) for that vacuum valve?

There's a button on the circuit board for syncing the remote buttons, so there's a chance it'll work. With the relay circuit I bought, you can set the jumpers so that a single button operates like a toggle (on/off) rather than using two separate buttons like I did in this instance, so you only really need one spare button on your current remote.

Just checked my ebay history, the part number is 1742712. I'm sure these vacuum solenoids are a generic part though and probably used in other applications.
 

newGTS

New Member
Messages
6
Paul, thank you for this excellent write-up. I'd been looking into the electronic exhaust control modules from Capristo, FD, and Forza, but after seeing your and Andy's posts, I couldn't resist giving the DIY route a shot. I also prefer this simpler mechanical solution vs. an electronic one- it should make any potential troubleshooting down the line very straightforward vs. dealing with a module that intercepts ECU signals.

I think I have a handle on all the components and setup, but wanted to ask if you know the specs/sizing on the vacuum tubing? Thanks again for the great post.
 

CatmanV2

Member
Messages
48,547
Brilliant, thanks. Think the solenoid on my GTS Auto is playing up.

Bob, that's not the exhaust solenoid. It's the one that controls the secondary air pump. If your exhausts are playing up it's at the back.

Probably

C
 

Andy Marshall

Member
Messages
297
Paul, thank you for this excellent write-up. I'd been looking into the electronic exhaust control modules from Capristo, FD, and Forza, but after seeing your and Andy's posts, I couldn't resist giving the DIY route a shot. I also prefer this simpler mechanical solution vs. an electronic one- it should make any potential troubleshooting down the line very straightforward vs. dealing with a module that intercepts ECU signals.

I think I have a handle on all the components and setup, but wanted to ask if you know the specs/sizing on the vacuum tubing? Thanks again for the great post.

The vacuum tubing is 3mm id rubber pipe - the same stuff used for fuel lines.
 

namaste

Member
Messages
212
Paul, thank you for this excellent write-up. I'd been looking into the electronic exhaust control modules from Capristo, FD, and Forza, but after seeing your and Andy's posts, I couldn't resist giving the DIY route a shot. I also prefer this simpler mechanical solution vs. an electronic one- it should make any potential troubleshooting down the line very straightforward vs. dealing with a module that intercepts ECU signals.

I think I have a handle on all the components and setup, but wanted to ask if you know the specs/sizing on the vacuum tubing? Thanks again for the great post.

I used some 3mm id silicone vacuum hose off ebay (about £3 a meter). I need to make some edits to the thread, basically you can access the vacuum pipes from above by removing one of the air box pipes above so no need to get under the car. Secondly, get yourself a mini piggy back fuse holder rather than a standard size so you can piggy back off one of the fuses at the front of the fuse box. And as Catman has said, what I thought was the factory vacuum solenoid isn't, its actually at the back by the tailpipes somewhere, but that makes no difference to the operation of this mod.
 

newGTS

New Member
Messages
6
Thank you guys, 3mm it is. I saw all the updates from Andy's thread- ready access to the vacuum tubing from above in the engine bay clinched it for me, as I didn't want to have to lift the car and remove the under bumper tray (thanks Catman). And I have a mini fuse tap that I'm planning to use on F21 (the fuse for front foglights which newer models don't have).

Paul, I purchased the same vacuum solenoid (1742712), and wanted to ask how you wired it in; the positive and negative connections are two exposed metal blades inside the plastic black housing- were you able to find the corresponding plug/harness, or is there a safe way to connect bare wire to these contacts? Appreciate the help!
 

CatmanV2

Member
Messages
48,547
Thank you guys, 3mm it is. I saw all the updates from Andy's thread- ready access to the vacuum tubing from above in the engine bay clinched it for me, as I didn't want to have to lift the car and remove the under bumper tray (thanks Catman). And I have a mini fuse tap that I'm planning to use on F21 (the fuse for front foglights which newer models don't have).

Paul, I purchased the same vacuum solenoid (1742712), and wanted to ask how you wired it in; the positive and negative connections are two exposed metal blades inside the plastic black housing- were you able to find the corresponding plug/harness, or is there a safe way to connect bare wire to these contacts? Appreciate the help!

Photo? It's probably just a standard blade connector.

http://www.maplin.co.uk/p/crimping-tool-kit-a33qw

C
 

namaste

Member
Messages
212
Thank you guys, 3mm it is. I saw all the updates from Andy's thread- ready access to the vacuum tubing from above in the engine bay clinched it for me, as I didn't want to have to lift the car and remove the under bumper tray (thanks Catman). And I have a mini fuse tap that I'm planning to use on F21 (the fuse for front foglights which newer models don't have).

Paul, I purchased the same vacuum solenoid (1742712), and wanted to ask how you wired it in; the positive and negative connections are two exposed metal blades inside the plastic black housing- were you able to find the corresponding plug/harness, or is there a safe way to connect bare wire to these contacts? Appreciate the help!

A couple of these (female blade crimps). Not sure what size they're exactly, I just had these in a bag of electrical bits. The blade gap is about 3mm wide, think the standard size might be 3.2mm if you're looking to buy some. After crimping I also used some heat shrink over the whole connector to keep them insulated from one another.

IMG_20170605_220402.jpg
 

newGTS

New Member
Messages
6
Here's a picture of the socket on the vacuum solenoid:

http://i.ebayimg.com/images/g/Gv0AAOSwhQhY7ASh/s-l1600.jpg

I have an old wiring and connector kit pretty much identical to the one Catman posted, but the quick disconnect terminals are all far too large (by almost 2X); I didn't realize they came in a size small enough to squeeze inside that space side by side. I'll have to dig around the local auto parts shop my next free weekend. Thanks for the tips!
 

Contigo

Sponsor
Messages
18,376
What I want now is a button that actually shuts the valves but keeps the car in SPORT mode as my car is now illegal for track useage.
 

CatmanV2

Member
Messages
48,547
Here's a picture of the socket on the vacuum solenoid:

http://i.ebayimg.com/images/g/Gv0AAOSwhQhY7ASh/s-l1600.jpg

I have an old wiring and connector kit pretty much identical to the one Catman posted, but the quick disconnect terminals are all far too large (by almost 2X); I didn't realize they came in a size small enough to squeeze inside that space side by side. I'll have to dig around the local auto parts shop my next free weekend. Thanks for the tips!

Ahh probably not. That seems to be some kind of socket. No idea where you'd get the plug.

C
 

CatmanV2

Member
Messages
48,547
What I want now is a button that actually shuts the valves but keeps the car in SPORT mode as my car is now illegal for track useage.

Run a bypass around the solenoid at the rear with another valve and a couple of t-pieces. Slightly more awkward, but certainly possible

C