Installing Exhaust manifold and Downpipe
- Thread starter IggyPop
- Start date
Carlinator
Member
- :
- 2003.5 MSP
I had the same thing after I put my exhaust on. I put the SSAFC on a week ago and it cured it.
How hard are they to install and set up? Can you pass inspection with one of those in place?
- :
- 2003 mazdaspeed protege
not hard at all. just cut and splice/tap I think 7 wires, setup they can with preloaded map and are user programmable, hook up a vacuum line. That's it. As for inspection I don't have to go thur inspection so I don't know.
That's what I thought. There is a guy selling one on here for like 400$. It's brand new. I see you can buy them brand new from PG though. I should probably pick up some 440cc WRX injectors too huh?
Carlinator
Member
- :
- 2003.5 MSP
Yeah just to chime in, the only thing that would really fail you on inspections would be a MIL due to catless exhaust like I've got, but it sounds like that's not an issue for you, so you should be golden. Just try and tuck it somewhere they wont see it, having a mass of wires hanging out in the open going to some mysterious black box may raise a few eyebrows. 
Also, if you don't have one, I'd highly recommend getting a wideband O2 sensor with a gauge, AFR monitoring is VERY important on these cars. If you plan on upping boost OR perfecting a tune for your setup, it'll be essential.
As for the injectors, they're not gonna be necessary right away. Fuel cut is when the injectors reach full duty cycle and can't keep up with the amount of air you're pulling in, so the ECU shuts them off; that's not what's happening here. The hesitation you're seeing is not fuel cut, jdwk has a nice writeup on why it happens here. Basically it's due to a too-high switchover from closed to open loop. Boost builds, O2 sensor reads lean, ecu trims it ultra-rich to try and keep the AFR at 14.7, then when the kickover happens that rich trim adds even more fuel to our already-rich stock fuel map, so we get hesitation. Fuel cut only really becomes an issue at higher boost.
A term you should know is scavenging. Basically, all cars have some Overlap, a split second during the engine cycle where the exhaust valve has not closed all the way, but the intake valve has begun to open. This is useful, because the exhaust gases moving in the tailpipe have momentum, and they help pull fresh air-fuel charge into the cylinder; that's scavenging. Higher cam overlap = more scavenging. Generally speaking, for performance, more is better at higher rpms, but less overlap is more streetable, at least for daily driving when you're not getting on the gas. When you put on a bigger exhaust, though, it flows more freely and scavenges more mixture all the way through to the exhasut, instead of leaving it in to be compressed. That's why it's possible to go too big on an exhaust, especially on N/A motors. It generally isn't as bad on turbo cars, since the turbo itself provides some backpressure. On our cars, though, that unburnt mixture has more free oxygen than a properly burnt charge; the O2 sensor can't tell this apart from a lean-burning charge, so it reads lean and makes the hesitation worse. I had it when I put my downpipe on, it worsened to a full-on misfire when I put the exhaust on. The AFC fixes that situation, through... magic.
Holy wall of text, batman! Short answer: AFC good, Wideband good, injectors good but not necessary right now.
Also, if you don't have one, I'd highly recommend getting a wideband O2 sensor with a gauge, AFR monitoring is VERY important on these cars. If you plan on upping boost OR perfecting a tune for your setup, it'll be essential.
As for the injectors, they're not gonna be necessary right away. Fuel cut is when the injectors reach full duty cycle and can't keep up with the amount of air you're pulling in, so the ECU shuts them off; that's not what's happening here. The hesitation you're seeing is not fuel cut, jdwk has a nice writeup on why it happens here. Basically it's due to a too-high switchover from closed to open loop. Boost builds, O2 sensor reads lean, ecu trims it ultra-rich to try and keep the AFR at 14.7, then when the kickover happens that rich trim adds even more fuel to our already-rich stock fuel map, so we get hesitation. Fuel cut only really becomes an issue at higher boost.
A term you should know is scavenging. Basically, all cars have some Overlap, a split second during the engine cycle where the exhaust valve has not closed all the way, but the intake valve has begun to open. This is useful, because the exhaust gases moving in the tailpipe have momentum, and they help pull fresh air-fuel charge into the cylinder; that's scavenging. Higher cam overlap = more scavenging. Generally speaking, for performance, more is better at higher rpms, but less overlap is more streetable, at least for daily driving when you're not getting on the gas. When you put on a bigger exhaust, though, it flows more freely and scavenges more mixture all the way through to the exhasut, instead of leaving it in to be compressed. That's why it's possible to go too big on an exhaust, especially on N/A motors. It generally isn't as bad on turbo cars, since the turbo itself provides some backpressure. On our cars, though, that unburnt mixture has more free oxygen than a properly burnt charge; the O2 sensor can't tell this apart from a lean-burning charge, so it reads lean and makes the hesitation worse. I had it when I put my downpipe on, it worsened to a full-on misfire when I put the exhaust on. The AFC fixes that situation, through... magic.
Holy wall of text, batman! Short answer: AFC good, Wideband good, injectors good but not necessary right now.
Last edited:
Heck of a post there. Very informative. I am currently in the middle of my Wideband install. Have the wire sitting on my dash now. Just need to run power to the gauge and mount the gauge pod. You have to understand I have a 2 year old and a 38 week pregnant wife. Minutes are very precious right now. I will keep my eye on SSAFC's that pop up. That will me my next big purchase and hopefully my last.
Carlinator
Member
- :
- 2003.5 MSP
True that, family > car any day.
Ok got my Wideband hooked up. It is reading 10 when I'm in the lower gears, at about to 3K - 5K RPMs and building boost. It fluctuates between 15 - 16 when I am in 5th gear going pretty fast, 80mph or so. I noticed that when I feel that hesitation, the AFR goes to like 16 then drops back to 15 or high 14's. It mostly hangs around 14 - 15 when I'm just tooling around. The car is not driving horribly. It is definitely faster after the mods I have done. I just wish it was smoother through the acceleration. I will just have to be on the look out for an SSAFC. And if anyone is in the area and wants to install one for me, let me know. I have no time and . am willing to pay a good amount to have someone else do this for me. I will have to take some pics of my new gauge pod. It is a driver side pillar mount. Fits 2 gauges. I got the AEM AFR and boost gauges. The boost gauge was kind of a waste of money. I already have a blitz dual TT gauge. It measures in HKPA. Which is actually more accurate then the AEM boost gauge. Since it measures down to the decimal point.
It also could be like 8 other things. Being as that I just replaced the midpipe and added the MIL eliminator, I'm gonna go with O2 sensor. I will check my plugs also. I just replaced them 10K miles ago. They are colder plugs.
Does your OBDII scanner do live data or just read codes? If you have a scanner check out your fuel trims and your duty cycle. You could very well be dumping too much fuel and misfiring. What does your AFR read after going to open loop (4200rpms)? There are plenty of codes for a faulty O2, but with a scanner you can also see the O2 voltage as well.
Scanners are definitely worth the $100 investment. I bought a bluetooth one off some shady Chinese website that works great with the Torque app. Took over a month to get here but it was worth the wait. I bought a harbor freight one while I was waiting and then returned it when the bluetooth module came.
Scanners are definitely worth the $100 investment. I bought a bluetooth one off some shady Chinese website that works great with the Torque app. Took over a month to get here but it was worth the wait. I bought a harbor freight one while I was waiting and then returned it when the bluetooth module came.
AFR's read as low as the wideband goes, which is 10. That is most likely my problem. Hence why I need a SSAFC.
where did u get your gasket for the manifold to turbo?? which is just a t25 flange.. but i went to the mazda dealer and they cant get it without buying the whole manifold!!! so if anyone has input on were to get one that would be great.. and i found some online at random places but dont trust those sites...
Carlinator
Member
- :
- 2003.5 MSP
That's bulls***, I ordered both the mani-head and mani-turbo gaskets through my dealer. Go back and put the screws to them.
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