Ocelot

So the FCD tricks the ECU into thinking theres less psi than there actuall is (if I understand that right). So wouldn't it tell it to give less gas than is required? Does this become a problem right after you reach the fuel cut? With a Walbro 255 pump, how much can you boost before it becomes neccessary to get a S-AFC?

Heres the setup I plan on having once the money comes in:

New Boost Gauge - Have
FCD - Have
A'pexi Intake - Have
Bonez 2.5" DP
Bonez 2.5" High Flow Cat
Walbro 255 Pump
Ported Wastegate<--? (This is what I have questions on)

If I understand correctly, porting the wastegate will create less boost. I haven't been able to find some things, so I have a few questions on this. When you have intake and exhaust mods, and you port the wastegate, and it goes back to the stock PSI for instance, whats the advantage of having stock boost psi with the ported wastegate and mods compared to just stock boost. Does the boost come quicker, last longer, or what? If I had these mods, and ported my wastegate up to the flapper doors limits, what psi would I roughly be around? At that point, should I be getting a MBC to be able to get to around 10 psi with that setup and a ported wastegate? I've heard that 10psi is a safe number to go with, but would it be safe to always run at 10psi, or just have it lower and use the mbc to put it up to 10psi only when I really wanted to boost higher?

Could someone help me out and give me a few pointers on my setup?

Sideways7

iTrader: (7)

There was a post a little while back addressing whether the FCD causes less fuel to be delivered under boost. I believe the general consesus was that it doesn't effect it much, but I would search for it and read the whole thing.
From what I can tell, porting the wastegate doesnt neccesarily reduce boost, (although it might, I'm not sure) what it does is help eliminate boost creep, which can be very bad for an engine. I dont know about the point at which you should get a microtech or s-afc, or something, but there are lots of other people in the forum that do know.

CRXtoRX7

The wastegate's purpose is to let out the excess boost once you've reached the intended level, but when you have mods, and the turbo is spooling more, the wastegate is too small and can't release enough of the excess. Porting the wastegate will still let you boost up like normal, but once you've reached high boost, the wastegate will release the excess and allow you to stay at that level. I would reccommend getting the MBC (15 off ebay) and porting the wastegate, you will be safer and in more control of your turbo in the end.
-Ben

ilike2eatricers

Yea with the mods you have you are above stock boost levels, most likely too high for your wastegate to handle venting off all the excess boost so you will creep higher than what you actually want to boost which is harmful to your motor. When you port the wastegate and make the flapper larger than the original one you can vent off more excess boost allowing you to boost how much you want to (depending on how large you port the wg) without spiking hopefully.

The MBC controls how much the wastegate will open and that is how it raises your boost by not letting excess boost vent off. Hope you understood all that I typed it pretty quickly.

Ocelot

So if I got an MBC, should I leave it low and only put it up at around 10psi when I needed it, or just keep it at 10psi all the time and i'll be fine?

CRXtoRX7

Also, 10 psi is safe to run at all times, but you may want to look into bigger secondaries and the fuel pump, at which point you will need a piggyback and some tuning.

I read that the FCD affects the fuel very minimally.

All in all, I wouldn't take any shortcuts.
Get an MBC, port the wastegate, injectors,s-afc, fuelpump, tune.

you should have a safe setup with that.
anyone feel free to correct me...
-Ben

Ocelot

Is it necessary to make the flap bigger, or is it safe enough to port it up until the what the stock one can handle?

CRXtoRX7

my friend ported the wastegate and left the flapper stock, and he runs 10 psi with no creep.

Ocelot

Would I be fine if I just say went with the Walbro 255, MBC, ported wastegate, and left the bigger secondaries and s-afc until I wanted to dyno tune it?

ilike2eatricers

Well the point of making the flapper bigger is so that you can port the wastegate more than you would be able to if you didn't.

If you ported the WG too much the flapper may get stuck and you know what could happen...

Some people weld on a metal washer to enlarge the diamter.

I started a thread about using a pop off valve vs porting the wastegate. Hopefully I will get some replies.
https://www.rx7club.com/showthread.p...hreadid=257690