Rainbow mess
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Junior Member
Joined: Oct 2019
Posts: 28
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From: Kansas
Rainbow mess
So I’ve seen some builds that have taken the rainbow wire mess out along with most of the rest of the wires too. What exactly are those wires and how do I go about removing them. If I’m correct I’m pretty sure it has to do with emissions right?
85 gsl
85 gsl
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
What you call a "Rainbow Mess" is what the rest of us call "The Rat's Nest".
The Rat's Nest is an arrangement of various Vent and Vacuum Solenoids, Air Relay Switches and vacuum hoses which are mounted to the driver's side of the top of the engine on 1st Gen cars. The fuel-injected -SE's (84/85) have fewer of these, but control Vacuum Advance for the distributor, Bypass Air Controlling to keep the engine from dying when the A/C or headlights are turned on, and Air Switching using Vent and Vacuum Solenoids to control airflow for the Secondary Air Bypass valve which moves air from the intake into the exhaust stream to effect better emissions control.
These solenoids and switches are sometimes removed by owners to clean up the engine bay and make things easier to troubleshoot for areas that don't require emissions testing. For cars driven in most US cities, the Rat's Nest is necessary to be sure the car will pass both visual and performance testing (dyno) where it's required by law for registration renewal. On the -SE cars, removal of the Rat's Nest is NOT RECOMMENDED as it will lead to driveability issues, as they've already been reduced to only those necessary to function.
If you choose to remove your Rat's Nest, there are plenty of write-ups on this site to assist with that if you search (*knowing what it's called is important, hence my post!). If your car is still registered in your state / county and requires emissions testing, be careful about what you choose to remove, as it will affect performance, fuel mileage, and emissions.
Simply stated (too late?), the Rat's Nest is there to keep the engine behaving under normal driving conditions, and Mazda spent $$$ to be sure that it has everything it needs and nothing it doesn't when it left the factory. If you remove those parts, hang onto them, because you may find that the car drove better with them on, and they'd be $$$ to source and replace if you change your mind,
The Rat's Nest is an arrangement of various Vent and Vacuum Solenoids, Air Relay Switches and vacuum hoses which are mounted to the driver's side of the top of the engine on 1st Gen cars. The fuel-injected -SE's (84/85) have fewer of these, but control Vacuum Advance for the distributor, Bypass Air Controlling to keep the engine from dying when the A/C or headlights are turned on, and Air Switching using Vent and Vacuum Solenoids to control airflow for the Secondary Air Bypass valve which moves air from the intake into the exhaust stream to effect better emissions control.
These solenoids and switches are sometimes removed by owners to clean up the engine bay and make things easier to troubleshoot for areas that don't require emissions testing. For cars driven in most US cities, the Rat's Nest is necessary to be sure the car will pass both visual and performance testing (dyno) where it's required by law for registration renewal. On the -SE cars, removal of the Rat's Nest is NOT RECOMMENDED as it will lead to driveability issues, as they've already been reduced to only those necessary to function.
If you choose to remove your Rat's Nest, there are plenty of write-ups on this site to assist with that if you search (*knowing what it's called is important, hence my post!). If your car is still registered in your state / county and requires emissions testing, be careful about what you choose to remove, as it will affect performance, fuel mileage, and emissions.
Simply stated (too late?), the Rat's Nest is there to keep the engine behaving under normal driving conditions, and Mazda spent $$$ to be sure that it has everything it needs and nothing it doesn't when it left the factory. If you remove those parts, hang onto them, because you may find that the car drove better with them on, and they'd be $$$ to source and replace if you change your mind,
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 28
Likes: 1
From: Kansas
What you call a "Rainbow Mess" is what the rest of us call "The Rat's Nest".
The Rat's Nest is an arrangement of various Vent and Vacuum Solenoids, Air Relay Switches and vacuum hoses which are mounted to the driver's side of the top of the engine on 1st Gen cars. The fuel-injected -SE's (84/85) have fewer of these, but control Vacuum Advance for the distributor, Bypass Air Controlling to keep the engine from dying when the A/C or headlights are turned on, and Air Switching using Vent and Vacuum Solenoids to control airflow for the Secondary Air Bypass valve which moves air from the intake into the exhaust stream to effect better emissions control.
These solenoids and switches are sometimes removed by owners to clean up the engine bay and make things easier to troubleshoot for areas that don't require emissions testing. For cars driven in most US cities, the Rat's Nest is necessary to be sure the car will pass both visual and performance testing (dyno) where it's required by law for registration renewal. On the -SE cars, removal of the Rat's Nest is NOT RECOMMENDED as it will lead to driveability issues, as they've already been reduced to only those necessary to function.
If you choose to remove your Rat's Nest, there are plenty of write-ups on this site to assist with that if you search (*knowing what it's called is important, hence my post!). If your car is still registered in your state / county and requires emissions testing, be careful about what you choose to remove, as it will affect performance, fuel mileage, and emissions.
Simply stated (too late?), the Rat's Nest is there to keep the engine behaving under normal driving conditions, and Mazda spent $$$ to be sure that it has everything it needs and nothing it doesn't when it left the factory. If you remove those parts, hang onto them, because you may find that the car drove better with them on, and they'd be $$$ to source and replace if you change your mind,
The Rat's Nest is an arrangement of various Vent and Vacuum Solenoids, Air Relay Switches and vacuum hoses which are mounted to the driver's side of the top of the engine on 1st Gen cars. The fuel-injected -SE's (84/85) have fewer of these, but control Vacuum Advance for the distributor, Bypass Air Controlling to keep the engine from dying when the A/C or headlights are turned on, and Air Switching using Vent and Vacuum Solenoids to control airflow for the Secondary Air Bypass valve which moves air from the intake into the exhaust stream to effect better emissions control.
These solenoids and switches are sometimes removed by owners to clean up the engine bay and make things easier to troubleshoot for areas that don't require emissions testing. For cars driven in most US cities, the Rat's Nest is necessary to be sure the car will pass both visual and performance testing (dyno) where it's required by law for registration renewal. On the -SE cars, removal of the Rat's Nest is NOT RECOMMENDED as it will lead to driveability issues, as they've already been reduced to only those necessary to function.
If you choose to remove your Rat's Nest, there are plenty of write-ups on this site to assist with that if you search (*knowing what it's called is important, hence my post!). If your car is still registered in your state / county and requires emissions testing, be careful about what you choose to remove, as it will affect performance, fuel mileage, and emissions.
Simply stated (too late?), the Rat's Nest is there to keep the engine behaving under normal driving conditions, and Mazda spent $$$ to be sure that it has everything it needs and nothing it doesn't when it left the factory. If you remove those parts, hang onto them, because you may find that the car drove better with them on, and they'd be $$$ to source and replace if you change your mind,
1985 rx7 GS
Joined: Dec 2016
Posts: 94
Likes: 11
From: Puyallup
https://drive.google.com/file/d/0BwO...w?usp=drivesdk
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
Last edited by Kdo58; Nov 4, 2019 at 06:29 PM. Reason: Updated
I removed the rats nest early one summer to "simplify" things.
After a summer of poor performance and bad gas mileage I put it back it.
Never again.
And thanks Long Duck for the explanation of why the rats are good for you.
After a summer of poor performance and bad gas mileage I put it back it.
Never again.
And thanks Long Duck for the explanation of why the rats are good for you.
I would counter LongDucks and Rays reasoning and say the rats nest is the result of using analog signalling (vacuum) to solve hard problem domains including emissions, mpg and drivability. I'm with KC in that its really all down to carb tuning. Modern EFI and computers solve all of this more accurately and easily but at the cost of the zoom factor, LOL
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84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
The Bosch L-Jetronic EFI on my GSL-SE still uses a Vent / Vacuum solenoid for timing control, and 2 Air Control Switches to actuate the Bypass Air Control Valve (*actually 2 systems, the Bypass Air and Air Control Valve...) to bump up engine RPM when the A/C or electrical system loads up. These are necessary even on an EFI car, as they're simple and reliable methods to control these functions without complicating the simple ECU on these cars.
If you can tune a carb and especially if you go Weber / Holley / Dellorto, then you don't need my advice on how the Rat's Nest works to make the engine behave. For all other methods, they do more good than harm,
If you can tune a carb and especially if you go Weber / Holley / Dellorto, then you don't need my advice on how the Rat's Nest works to make the engine behave. For all other methods, they do more good than harm,
The Bosch L-Jetronic EFI on my GSL-SE still uses a Vent / Vacuum solenoid for timing control, and 2 Air Control Switches to actuate the Bypass Air Control Valve (*actually 2 systems, the Bypass Air and Air Control Valve...) to bump up engine RPM when the A/C or electrical system loads up. These are necessary even on an EFI car, as they're simple and reliable methods to control these functions without complicating the simple ECU on these cars.
If you can tune a carb and especially if you go Weber / Holley / Dellorto, then you don't need my advice on how the Rat's Nest works to make the engine behave. For all other methods, they do more good than harm,
If you can tune a carb and especially if you go Weber / Holley / Dellorto, then you don't need my advice on how the Rat's Nest works to make the engine behave. For all other methods, they do more good than harm,
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
Wanna race? (*I'm honestly curious how the well-tuned carbs compare to OEM EFI with headers, exhaust and porting left equal - on a closed-course with professional drivers, of course!)
Interesting you should say that. My buddy has an RX8 that he had Petit Racing massage an engine for him. Well when we get together and go on a run, he was very surprised that my little 12A could keep up with his RX8. Obviously there is a weight difference there but that 8 should have walked away from me but it doesn't. Although its top speed may be better, have to get on a track to really see.
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