HugoW

Hi, I have a Speeduino ECU and a turbo on my 2004 1.8 VVT engine. And it all works! Well, to a certain extent. I have some issues and looking at a datalog, people who actually understand it say my MAP signal is not table. Since other sensors on the same 5V power and ground do give stable readings and the MAP sensor is on the PCB of the ECU, I suspect the hoses / lines carrying the signal are at fault somewhere. But where (there is no clear leak), and what is good practice?

At the moment, I have the lines like this:
From the outfeed of the turbo to the waste gate actuator is a direct line, with nothing in between. I would like to fit a boost control valve at a later date, but it’s not there, yet. My waste gate actuator is therefore acting on outfeed pressure of the turbo (before intercooler), not on manifold pressure.
I used the small steel vacuum take off point on the manifold close to the intake valve to run the line towards the ECU from. En-route to the ECU, it is T-ed off three times. First and second are close to the manifold take off point, to the fuel pressure regulator and to the blow off valve. The third is T-ed off right before the ECU, feeding a boost gauge in tomb stone.
I use silicon hose everywhere, as far as I can see it is not reinforced, with 4 mm internal diameter and 12-ish mm outside. Good for vacuum, but good for boost, too?
I read (googling) I need a vacuum block and route everything there. I saw a YT video on using PU lines and press fittings like used for compressed air. I also read about a vacuum damper somewhere, but I didn’t understand it and I haven’t found info / parts about it. I am wondering if keeping the turbo -> waste-gate line separate is a good thing or a bad thing. I am wondering if I chose the correct pick-up point from the manifold. Etc.

Please share your thoughts and experience with me,
Cheers,

Hugo

technicalninja

NO TEES is the best practice!!
Especially on the line to the wastegate (should come from pre throttle body/post intercooler)
The line to the ECU MAP sensor should come from manifold after throttle body.
The FPR and the BOV should also be to manifold post throttle body.

Different year Mazda manifold have different vacuum connections on them. Some years have delay valves and vacuum chambers inside the manifold.
Figuring which ones to use can be difficult.

I usually inspect vacuum routing inside manifold when it is off the engine, but you could use a vacuum gauge.
On a good manifold vacuum source the vacuum gauge will react instantly with throttle changes. The lowest reading will be at idle and the vacuum will drop off as the throttle opens.
At idle stock engine 17-21" at WOT with load (NOT revving it up stopped) you should be less than 2"
A good "ported" manifold source will have no vacuum at idle but will gain vacuum as the throttle opens and will have fairly high vacuum at WOT.
Idle 0 vacuum, WOT 20" vacuum.
The ports with internal chambers and delay valves (these are external in the hose routing) will do substantially different things than the above and should not be used for connecting your stuff.
You will not use the ported sources either.

A dead give away for how a manifold vacuum source should look like is the PCV connection or the brake booster connection. Both of those are manifold vacuum only.
Adapt the booster source down to fit your vacuum gauge. You can use your boost gauge as a vacuum gauge and do not have to purchase another tool.
Only use sources that respond exactly like the brake booster source.

Any T is a possible leak point and loss of signal to the ECU or the waste gate could cost you a motor.
Silicone is fine to use but it must really stick to the hose bard tightly. Most use zip ties to try and help.
If I can pull it off by hand easily it's not good enough for me.

HugoW

What is the benefit of connecting the waste gate actuator between intercooler and throttle valve? I see a lot of them attached to the turbo outlet, like I have it.

Hugo

technicalninja

Connected to outlet is normal OEM and it will work OK.

Connected to intercooler outlet/ pre-throttle blade takes into account both the reduction in pressure created by the intercoolers "drag" or resistance to flow and the reduction of pressure that occurs when you reduce the temperature of any gas (basic physics).

Connected to the outlet an 8 psi setting is down to 7 or lower by the time the air charge passes the throttle blade.

Connected to just before the throttle blade you will have 8 at the blade and 9+ at the compressor outlet.

This is the simplest explanation and can be misleading as your boost gauge (sourced from the manifold plenum) will show the same regardless of where you source your wastegate control.

technicalninja

The above was not completely correct...
If you have no method of controlling the boost setting besides adjusting waste gate pre-load then where you are connecting the line to the waste gate will have an effect on your boost level and you will be able to see it on a boost gauge.
This was a quick and simple way of adding another lb of boost by merely changing the reference point from compressor outlet to post intercooler.
You will see a change in boost, the car will be a tiny bit quicker to spool and it will hit a higher boost level (maybe 1 lb).
If it's more than 1 lb then you probably have too much restriction in the cold side (pipes, intercooler).

Now, with EBC this is all a moot point as the ECU will be controlling the signal to the waste gate and where the pressure to actuate the waste gate comes from does not really matter.
The EBC uses the MAP signal as the reference point for waste gate control. It does NOT use manifold pressure to control the gate.

It's still important to check the boost level against the boost at the compressor outlet to check for excessive restriction in the cold side but that is a one-time check and not an issue for normal operation.

Hope this helps...

ed1380

+1 for getting rid of Tees. Everything should have its own line. If there's not enough ports then use a distribution block. Feed that with a bigger line.

I've always used windshield washer line. Even survived 50psi spikes on the dsm. I also like sourcing boost from the compressor cover