SPT intake, no tune = less hp?
- Thread starter ShagginWagon
- Start date
all this SPT improvement-or-not stuff had me wondering...
so I went out at lunch today for a test ride...crikeys, my wag was GONE!
scorch marks on the pavement, a few bits of blown-up ECU on the ground.....?
Then, Nat'l Public Radio had a news blurb about a Space Station mission getting scrubbed for unknown debris in shuttle's intended orbit ??!!!
Moral of the story: don't bolt on both SPT exhaust AND intake in the same week...aka, be careful what you wish for.
so I went out at lunch today for a test ride...crikeys, my wag was GONE!
scorch marks on the pavement, a few bits of blown-up ECU on the ground.....?
Then, Nat'l Public Radio had a news blurb about a Space Station mission getting scrubbed for unknown debris in shuttle's intended orbit ??!!!
Moral of the story: don't bolt on both SPT exhaust AND intake in the same week...aka, be careful what you wish for.
not sound barrier, that got broken with the car just stock (ask stephjaz or ralli aboot that)
post SPT mods...mmmm, betta. once the boost got booztin and the intake whooshin and the exhaust g-r-r-rumbling....it was LIGHT SPEED doods.
point is, if I like the car much better after SPT mods (and yesss I doooo), they are a total success.
my challenge now is to stop the slide into hooligan ricer excess ...puh-LEEZ help me before I'm on eGay ordering carbon fiber ashtrays and neon under the floor mats :
x427
post SPT mods...mmmm, betta. once the boost got booztin and the intake whooshin and the exhaust g-r-r-rumbling....it was LIGHT SPEED doods.
point is, if I like the car much better after SPT mods (and yesss I doooo), they are a total success.
my challenge now is to stop the slide into hooligan ricer excess ...puh-LEEZ help me before I'm on eGay ordering carbon fiber ashtrays and neon under the floor mats :
ShagginWagon
New member
MMmmm....sweet STP exhaust. Too bad the one for the LGT is almost $1K...not sound barrier, that got broken with the car just stock (ask stephjaz or ralli aboot that)
post SPT mods...mmmm, betta. once the boost got booztin and the intake whooshin and the exhaust g-r-r-rumbling....it was LIGHT SPEED doods.
point is, if I like the car much better after SPT mods (and yesss I doooo), they are a total success.
my challenge now is to stop the slide into hooligan ricer excess ...puh-LEEZ help me before I'm on eGay ordering carbon fiber ashtrays and neon under the floor mats :x427
ruggedman
New member
In response to your first section; in an adiabatic situation yes, prehaps that might be true, but there's a lot more in a turbo system like compressor efficiency, intercooler efficiency, and laws of thermodynamics which would bore the crap out of you. Initial T is in these equations, but does it really matter that much? Not on a TD04 equipped wrx like i said earlier which is a system that's already out of it's ideal efficiency (at least compressor wise).
Now as for maf scaling, that's great, but there's problem is the turbulent/laminar flow change always occuring around the MAFS on poorly designed intake systems. The data you collect will probably let you know if it's junk, but it may not. Your measurements are only as good as the tools you use to measure them. If you use a ruler to measure a mile, you'll end up with guess....if you put our MAFS in a foreign environment you're doing the same thing. The bend in the pipe above is IMO enough to really F- up the readings the stock MAFS gets.
Is it a big deal? Probably not. You can probably make it work, and like Antonio and I agreed it could make more power, but it's pretty much a personal call. I'll personally leave the intake on the same shelf as the atmopsheric BOV until i've got a blow thru setup
S
shorty2
Guest
Where the hell did this post go wrong!!???
When you install an SPT intake, let your car idle for 5 min with the A/C off, then swithc the A/C on for 5 min. That lets the ECU learn the new intake. You'll be fine and the car will run mint.
frikkin ruggedman and Ralli, overcoplicatin' things....
When you install an SPT intake, let your car idle for 5 min with the A/C off, then swithc the A/C on for 5 min. That lets the ECU learn the new intake. You'll be fine and the car will run mint.
frikkin ruggedman and Ralli, overcoplicatin' things....
http://www.youtube.com/watch?v=k3HaRFBSq9kIn response to your first section; in an adiabatic situation yes, prehaps that might be true, but there's a lot more in a turbo system like compressor efficiency, intercooler efficiency, and laws of thermodynamics which would bore the crap out of you. Initial T is in these equations, but does it really matter that much? Not on a TD04 equipped wrx like i said earlier which is a system that's already out of it's ideal efficiency (at least compressor wise).
Now as for maf scaling, that's great, but there's problem is the turbulent/laminar flow change always occuring around the MAFS on poorly designed intake systems. The data you collect will probably let you know if it's junk, but it may not. Your measurements are only as good as the tools you use to measure them. If you use a ruler to measure a mile, you'll end up with guess....if you put our MAFS in a foreign environment you're doing the same thing. The bend in the pipe above is IMO enough to really F- up the readings the stock MAFS gets.
Is it a big deal? Probably not. You can probably make it work, and like Antonio and I agreed it could make more power, but it's pretty much a personal call. I'll personally leave the intake on the same shelf as the atmopsheric BOV until i've got a blow thru setup
I was going to respond, but it seems you incorrectly answered all your own questions.
ruggedman
New member
Sorry, sometimes the engineer busts out and flips out. :
It's not so much as the glass is half full or half empty, but rather that the class is twice as big as it needs to be O0
roadtrip1098
New member
I only read the first page, but there's a lot of misinformation so let me set some things straight.
Any higher flowing intake will cause the car to run more lean if the ECU isn't reset - especially intakes with larger diameter tubing because the MAF will not be calibrated to account for the additional air.
Resetting the ECU fixes some of the issues. When you reset the ECU, the car will purposely run richer in order to "learn" the new system. This will work under low load conditions when the car is adjusting the AFR by using the O2 sensors. When you peg the throttle though, your car will switch modes to more of a "fixed" map using the MAF reading to determine how much fuel to squirt in. Since the MAF is reading lower than actual, you will run lean.
Also, a higher flowing intake typically causes boost spike issues if left untuned. This is because air is allowed to enter so quickly that the wastegate duty cycles cannot compensate for the boost building faster.
Another issue caused by a CAI is related to the lean condition mentioned earlier. When you are running lean and boost is higher than it should be, typically there is more heat. Combine heat, more pressure and a lean mixture and the result is almost always a spark knock. Luckily our engines have a knock sensor which will help in preventing your motor from grenading from something like a CAI being installed. What will happen though is when the knock sensor determines that there is a knock, your car will pull timing and reduce the boost target values. So the result is less power.
Don't worry though, there are solutions to resolve this:
1. You can get a basic tune designed for the intake which will keep boost spike from occuring and also adjust the MAF readings
2. Until you get the tune, run some octane booster and try to stay out of boost.
If anyone has any questions regarding my information I'd be happy to go into more detail. Sorry if it has been covered already, but after reading the first page of info, no one had touched on why a CAI might not be making them any power.
Any higher flowing intake will cause the car to run more lean if the ECU isn't reset - especially intakes with larger diameter tubing because the MAF will not be calibrated to account for the additional air.
Resetting the ECU fixes some of the issues. When you reset the ECU, the car will purposely run richer in order to "learn" the new system. This will work under low load conditions when the car is adjusting the AFR by using the O2 sensors. When you peg the throttle though, your car will switch modes to more of a "fixed" map using the MAF reading to determine how much fuel to squirt in. Since the MAF is reading lower than actual, you will run lean.
Also, a higher flowing intake typically causes boost spike issues if left untuned. This is because air is allowed to enter so quickly that the wastegate duty cycles cannot compensate for the boost building faster.
Another issue caused by a CAI is related to the lean condition mentioned earlier. When you are running lean and boost is higher than it should be, typically there is more heat. Combine heat, more pressure and a lean mixture and the result is almost always a spark knock. Luckily our engines have a knock sensor which will help in preventing your motor from grenading from something like a CAI being installed. What will happen though is when the knock sensor determines that there is a knock, your car will pull timing and reduce the boost target values. So the result is less power.
Don't worry though, there are solutions to resolve this:
1. You can get a basic tune designed for the intake which will keep boost spike from occuring and also adjust the MAF readings
2. Until you get the tune, run some octane booster and try to stay out of boost.
If anyone has any questions regarding my information I'd be happy to go into more detail. Sorry if it has been covered already, but after reading the first page of info, no one had touched on why a CAI might not be making them any power.