Apexi intake = overboost????
#1
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Apexi intake = overboost????
I don't understand. I've just finished the apexi intake installation and I've gone for a nice ride. My car keeps the boost pattern (10-8-10) with some little 11.5-12 spike around 4500 rpm. But with the intake all is gone. I'm scared! In third gear boost have raised 14 psi (keeping it for more than 1000 rpm). Obviously this is not good.
And one more thing. Sometimes I hear water boiling when I shut off the engine. Some slight sound in some hose. But today I've heared it louder, stronger. I've put on the key and the fans have started to work instantly. I think I'll need a CAI box, cos the lower filter is just on the lower radiator hose and breathing directly from the radiator fan...
Any advice? Has anybody had this issue with only an intake mod????
And one more thing. Sometimes I hear water boiling when I shut off the engine. Some slight sound in some hose. But today I've heared it louder, stronger. I've put on the key and the fans have started to work instantly. I think I'll need a CAI box, cos the lower filter is just on the lower radiator hose and breathing directly from the radiator fan...
Any advice? Has anybody had this issue with only an intake mod????
Last edited by victorFD; 12-31-06 at 09:21 AM.
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a boost controller won't lower boost. I don't know why you're experiencing boost spike/creep w/ cat back and dp.
I had dp, midpipe, and 3" all the way back, the engine couldn't control my boost so i had to be really light on my right foot. I installed a cat & my PFC and it holds strong at 10lbs.
I had dp, midpipe, and 3" all the way back, the engine couldn't control my boost so i had to be really light on my right foot. I installed a cat & my PFC and it holds strong at 10lbs.
#7
RX-7 Bad Ass
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Some misinformation here. First off, you're at 3 mods on your car - intake, downpipe, catback. With that setup with the stock ECU, you WILL get boost spiking.
Next, a boost controller will help. The stock ECU's boost control map is VERY hardcoded, and will run away with the boost if you open things up. Putting on some sort of boost controller will take care of that problem.
The PowerFC gives you control of the factory boost solenoids, which will give you boost control to a good extent, but once you go farther (high-flow cat or midpipe) the factory pill-based boost control system won't cut it.
Anyhow, if you need something short term until you can afford a PowerFC, get a manual boost control setup. If you don't want to re-buy mods, get a good electronic boost controller. With either, keep boost at 10psi and the ECU will be mighty happy.
Dale
Next, a boost controller will help. The stock ECU's boost control map is VERY hardcoded, and will run away with the boost if you open things up. Putting on some sort of boost controller will take care of that problem.
The PowerFC gives you control of the factory boost solenoids, which will give you boost control to a good extent, but once you go farther (high-flow cat or midpipe) the factory pill-based boost control system won't cut it.
Anyhow, if you need something short term until you can afford a PowerFC, get a manual boost control setup. If you don't want to re-buy mods, get a good electronic boost controller. With either, keep boost at 10psi and the ECU will be mighty happy.
Dale
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#8
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how does a boost controller lower boost if all it does is trick the factory ecu into thinking boost is lower than it is? I can understand how my PFC can lower boost but that's because it replaces the ecu.
#10
2/4 wheel cornering fiend
Originally Posted by NissanConvert
how does a boost controller lower boost if all it does is trick the factory ecu into thinking boost is lower than it is? I can understand how my PFC can lower boost but that's because it replaces the ecu.
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Originally Posted by Kento
Because a good electronic boost controller doesn't "trick" anything...it takes over control of the precontrol and wastegate from the stock system, which the PFC will still only be able to control by itself without an additional boost control setup.
Originally Posted by NeoTuri
The PFC will no longer have any say in the matter, except maybe to fuel cut if the boost gets too high.
His car has no pfc, no boost controller.
#12
2/4 wheel cornering fiend
Originally Posted by NissanConvert
Okay, i'm a little confused. what i do understand is that a good boost controller takes control of the wastegate actuator away from the stock ecu.
What i don't understand is: Does *my* pfc driven car have any reason to have a piggyback boost controller?
What i don't understand is: Does *my* pfc driven car have any reason to have a piggyback boost controller?
#14
The shy megalomaniac
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Originally Posted by NissanConvert
What i don't understand is: Does *my* pfc driven car have any reason to have a piggyback boost controller?
#15
I did not know it possible to push 14psi through the stock cat w/ the stock ECU. I ran same mods as you for a while on stock ECU with no spikes, but I guess every car is different.
The PFC controls boost just like any other EBC would, and has a multitude of other options, its a great investment for your car. I would recommend keeping a light right foot until you get a PFC or some sort of EBC. Don't waste money on an EBC if you plan to get the PFC in the future, it controls boost just fine.
Does your car slowly raise to 14psi and stop? Does it ever go higher? Or is this an instant 14psi holding steady?
The PFC controls boost just like any other EBC would, and has a multitude of other options, its a great investment for your car. I would recommend keeping a light right foot until you get a PFC or some sort of EBC. Don't waste money on an EBC if you plan to get the PFC in the future, it controls boost just fine.
Does your car slowly raise to 14psi and stop? Does it ever go higher? Or is this an instant 14psi holding steady?
#16
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Originally Posted by Kento
If it has enough mods to overpower the stock boost control system, yes.
How can another boost controller actuate the wastegate to maintain my boost more efficiently than my PFC. I can understand doing it faster or what-not but if the problem is my unported wastegate then how would I fix that with another electronic box?
#17
Originally Posted by NissanConvert
Okay, for the record i have 3" exhaust turbo back, high flow cat, anti-rice cannon. I installed the cat last week, i installed the pfc yesterday. before i did that my boost controller was my right foot. since installing the cat and the pfc my boost holds strong at 10 lbs although some times at full throttle at the top of 3rd or fourth it'll creep to 12lbs. my peak injector duty cycle is 70.0%.
How can another boost controller actuate the wastegate to maintain my boost more efficiently than my PFC. I can understand doing it faster or what-not but if the problem is my unported wastegate then how would I fix that with another electronic box?
How can another boost controller actuate the wastegate to maintain my boost more efficiently than my PFC. I can understand doing it faster or what-not but if the problem is my unported wastegate then how would I fix that with another electronic box?
#18
2/4 wheel cornering fiend
Originally Posted by BoostedTimmy
It won't make a difference, PFC controls boost just any boost controller.
Originally Posted by NissanConvert
How can another boost controller actuate the wastegate to maintain my boost more efficiently than my PFC.
#19
2/4 wheel cornering fiend
Originally Posted by NissanConvert
I can understand doing it faster or what-not but if the problem is my unported wastegate then how would I fix that with another electronic box?
#21
Originally Posted by RX7LINK
+1
also PFC IS "NOT" A BOOST CONTROLLER. they sell additional add-on "boost controller kit" for PFC that cost around $350ish.
also PFC IS "NOT" A BOOST CONTROLLER. they sell additional add-on "boost controller kit" for PFC that cost around $350ish.
As I understood that kit just replaced the already existing solenoids and gives you the option to quickly jump between a couple boost level settings. I can see that and a standalone EBC being useful for single turbo cars but what could it possibly do on the stock TT system? The only advantage I see with that or any other EBC would be the preset boost levels and new solenoids. I can adjust boost levels from my PFC already with the commander. If the PFC does not control boost than somebody please tell me what controls the boost on my car?
#22
Mazzei Formula
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VERY SIMPLE ANSWER
i had the exact same problem
PROFEC B SPEC II fixes it completely
i had more severe spiking than you are experiencing...up to 17lbs of boost...i thought for sure that a boost controller could not fix it...well i was completely wrong
for now pull off the pressure tank and unclip the electrical connectors to the two solenoids u will run at 7psi on the primary turbo only (safety until a boost controller arrives)
pfc cannot control the boost as the solenoids do not respond quick enough even with interrupted duty cycling control
i had the exact same problem
PROFEC B SPEC II fixes it completely
i had more severe spiking than you are experiencing...up to 17lbs of boost...i thought for sure that a boost controller could not fix it...well i was completely wrong
for now pull off the pressure tank and unclip the electrical connectors to the two solenoids u will run at 7psi on the primary turbo only (safety until a boost controller arrives)
pfc cannot control the boost as the solenoids do not respond quick enough even with interrupted duty cycling control
#24
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Originally Posted by BoostedTimmy
I did not know it possible to push 14psi through the stock cat w/ the stock ECU. I ran same mods as you for a while on stock ECU with no spikes, but I guess every car is different.
#25
2/4 wheel cornering fiend
Originally Posted by BoostedTimmy
I can see...a standalone EBC being useful for single turbo cars but what could it possibly do on the stock TT system? The only advantage I see with that or any other EBC would be the preset boost levels and new solenoids.
Originally Posted by BoostedTimmy
Makes sense that it would help control spiking but that seems like a band-aid to another problem.