Okay, I've been trying to save up for the PFC for a really long time now. But between rent, school, ins., light, food, etc., I don't think I'll be getting it any time soon.

So my question is...with me running dp, mp, + k&n cone filters, would I be okay just adding a boost controller (ProfecB, HomeDepot, etc.)? As long as I'm not running any more than 10psi, I should been fine with fuel right? Someone please give me some info.

 

BUMP

 

https://www.rx7club.com/forum/showth...hreadid=196931

 

If you can successfully keep boost @ 10 lbs, then you will be fine. The real problem is trying to maintain only 10 psi with a MP. I've seen my friend Mild7's car get boost creep, and yet I've heard from Zerobanger that he doesn't. This creep isn't a boost controller issue, it's an insufficient wastegate size issue....

 

I have K&N drop in replacement, DP, gutted main cat, Greddy Cat back, profec B. I have it at 10 psi with no creep or spiking what so ever. Runs fine.

 

 

i would take out the mp just to be safe.

 

I second that. Give it a try, if you have creep you can always put the cat back on, or sell the MP for a high flow. Just be careful when testing it.

 

Me too. Everyone misses the fact that just because you are at 10 psi that doesn't mean the motor is safe. The volume of air passing through the motor is what determines how much fuel you need, not the pressure.

 

i have a custom intake that i made w/ two K&N cone filters, DP, MP, and cat-back with a ported wastegate and no boost controller @ 11 psi and it never goes any higher. my car has been like that for a while and i have been fine.

 

From what i understand even if your only at 10 psi you'll still be adding more air flow to the engine no matter how much boost your running. And you won't be adding any fuel of course by those mods. So therefore you'll be running lean and I would assume with an unported wastegate you will get a spike boost controller or no boost controller. So basically

Your mods=more air=same fuel=spike=ping=Blown motor

 

Wade has done some extensive testing to show that at 10 PSI, the stock ECU is still pretty rich with quite a few bolt on's:

http://www.newwave.net/~flanham/wlan.../3modrule.html

 

I would play it conservative and just get the downpipe and no midpipe or boost controller. The downpipe itself should raise your boost to 11-12 psi provided you have healthy turbos and your car might run better with just the downpipe. With the mp and boost controller, not only will your car stink but it will get louder. Save the money from the mp and boost controller for that upgraded ECU and go from there

 

ive always heard its o.k. long as you keep 10psi... Ive just did full exhaust with pfc and still spikes..

 

oh.. i also have avcr to control the boost

 

Thanks for the replys.

The PFC can be set so that if there IS some boost creep or spikes, the PFC will just dump more fuel in right?

 

You can always put in some restrictor plates in between the DP and MP to help regulate your boost.
The only thing I would be worried about would be with a MP the flow at 10psi would probably be a little more than the stock ECU richness would safely handle. With some restrictor plates it would back the flow down a bit at 10psi. I ran DP and MP with stock intake K&N drop in for a while before my PFC, but the A/F guage was showing middle ground instead of rich.

 

That workd, but then why have a midpipe

 

You put a mid pipe and restrictor plates in when you pull your air pump, because your main cat will clog on you.

 

Can someone help me with this question now? What I'm asking is...with the PFC, are you pretty much protected against boost spikes/creep? Because if that's the case, then I'll just keep trying to save up for it.

 

Basically the Factory ECU fuel cuts at 11.1 psi or something pretty close. So when you boost spike for a short amount of time you go into fuel cut on an already potentially lean condition. The PFC remaps the fuel curve for all boost levels based on your mods, and handles higher boost pressure upto your boost sensor limit of around 16psi. That's why everyone says that if you can control the boost spikes you will be fine. The PFC will not magically take away the boost spikes, but it will adjust things to help them level out a bit and to handle the 11.something psi and up conditions.

 

Thanks Conv.WS6.

I guess I'll just keep saving up for the PFC insted of trying to take the cheap way out.

 

That is misleading info.

The stock ecu will enact fuel cut at 10.7 psi above 6k rpm only if it is sustained boost. It ignores short term spikes--it does not supply enough fuel for these and will NOT fuel-cut.

The PFC doesn't remap anything. It has to be tuned. Your statement implies that the PFC self adjusts. Also, boost spikes are STILL a problem with the PFC if you still have the stock fuel system. If you are spiking to 15 psi for example, your injectors are beyond maxed out everytime it happens and you may not supply enough fuel.

To get back to the other argument, I have no doubt that the stock ecu maps will supply enough fuel for all the bolt-ons at 10 psi. However, actually maintaining 10 psi without restrictors (I agree DamonB, what's the point?) or porting the wastegate is not possible on a properly functioning car. Also, there is the ignition timing issue. When you are flowing more air and making more power, the ignition timing needs to be retarded.

Myself, I am running intake, SMIC, downpipe, and cat-back at 10 psi with the stock ecu. I have had no problems and am not running lean (at WOT anyway...). Do I feel confident that the car is 100% safe to drive, especially once the cold winter air arrives? No, which is why I will be installing a PFC soon. Well, that and to run more boost, get a smoother running car, control fan operation, etc........

 

Oh boy

 

Tyler strikes again . I was reading the post in question and scratching my head, saying to myself, "Self, that ain't right." Good advice, Big Stud Daddy