RotaryMaybe

hey guys i just got my fd and im running the stock turbos with a few uprades. Fluidyne rad, silicon hoses, aftermarket AST, turbo timer and down pipe. I was told that i should get an HKS AFR(air fuel ratio regulator)? Im not gonna be doing any heavy power upgrades so im more concerned with the longevity of the motor....any suggestions do as far as fuel mgmt mods for relaiblity? Should i get the HKS AFR? any other recommendations?

Mahjik

iTrader: (1)

You don't need to mess with that unless you plan on upgrading your turbos or running a lot of boost (something over the stock boost levels).

911GT2

If you really want, you can get a boost controller. Manual ones can be made for about $40 from Home Depot parts. Electronic ones can run to $350 or so. But if thats all you're planning on doing as far as power mods, you don't need any sort of fuel management above stock levels.

kyle@insight

No fuel management is needed past stock boost levels. However, if you plan to upgrade your exhaust any further you'll start to experience boost creep where fuel management upgrades would be good, that or you can get a good boost controller and keep the boost at stock levels as 911GT2 suggested. For fuel management you can get either a Pettit or M2 ecu, or if you want full adjustability an Apex Power FC is a favorite amongst FD owners.

RotaryMaybe

SO IF I CHANGE THE DP AND TO A 3INCH CATBACK I SHOULD GET AN UPGRDADE ECU OR POWER FC? YEAH I REALLY WOULDN'T WANT TO HIT A BOOST SPIKE

Mahjik

iTrader: (1)

Most people don't experience any problems with just changing out to a downpipe and a catback. If you do experience boost spikes, that can be easily controlled with a boost controller.

The problems come when changing out the main cat to a midpipe.

RotaryMaybe

i forgot to say that the main cat has a test pipe thorugh there.....but i don't understand, why would i need the a boost controller if im not planning on raising the boost?? If i get a boost controller, doesn't most people set the lowest psi to stock boost?? Or is it lower?? basically, do i need a boost controller? and how much should i run boost safely with all these mods(catback, test pipe, downpipe) in mind? lower then 10??

Mahjik

iTrader: (1)

Boost controllers "control" boost. The also help control boost spikes should you have them.

Without an upgraded ECU, you should keep the boost at stock levels (stock boost pattern is 10-8-10).

Check your boost pattern:

http://www.scuderiaciriani.com/rx7/boost_test.html

Make sure you aren't experiencing fuel cut or any boost spikes.

kyle@insight

You need a boost controller. Reason being, the wastegates on the turbos are undersized, they can't bleed off the excess boost quick enough when the intake or exhaust has been opened up. This is what causes the spikes. When you spike you're hiting 1-2psi more than what it's actually 'set' at, this case being the 10psi. Your stock ECU will not compensate more fuel for more boost, this leans to a lean condition which sometimes causes motors to blow. With a boost controller, you will be able to stabilize the boost and not have to worry about boost creep.

On wastegates that are spring controlled, usually the stock boost is the lowest seting you can go with. However a 7 doesn't have wastegate springs, it has an actuator. You can turn the boost down to 7psi if you really wanted too, but it'll run pig rich. You don't want to go over the stock 10psi without an ECU upgrade.

RotaryMaybe

thanks for all the info guys. However, if i would hit a boost spike and i was already at 10psi, even if i have a boost controller or not how would it prevent the spike from being bad with the boost controller? I would suill have to get an uprgaded ecu to fix that problem. Given i put the the boost controller down to let's say 8psi then when i hit a boost spike the ecu still wouldn;'t know how much fuel to give off at the sudden increase of 2psi..how would the boost sontroller fix this problem. Also if i stay at 7psi ill be running rich..so what do i do? sorry if im being hard headed but it doesn't make sense to me. My intake is still stock and i will keep it that way. To avoid the spikes completely, shouid i replace the midpipe back tot he main cat or even a high flow cat??

RotaryMaybe

or are you guys saying that if get a boost controler and lets say i keep it at 10psi...it would avoud bopost spikes all together....if so, sorry about the top thread=)

Mahjik

iTrader: (1)

Boost controllers are able to handle boost spikes. You just set the boost controller for the stock 10 PSI and you'll be fine.

Boost creep is a different story altogether. Boost creep is when there is too much for the wastegate to handle. Therefore porting the wastegate is the next step to controlling boost creep (or adding restriction to the exhaust).

RotaryMaybe

thanks mahjik, so for how put in a boost controller and put the main cat back on to put more restriction on the exhuast? thanks guys, you've been great and it's great to finally own an fd=)

RotaryMaybe

i meant, for now just put in the boost controller and the main cat back on and ill be fine ?

Mahjik

iTrader: (1)

Just putting the main cat back on will probably keep you safe. After that, just keep an eye on your boost levels. If you get spikes, then you'll need a boost controller.

RotaryMaybe

yeah...i was told to put the maincat on immediately so i don't mess up my engine...i guess ill be boosting too much and the ecu wouldn't know how to cmpensate that....it's at the shop right now so im gonna have to look for a cat and bring it to them...anyone know how much a maincat will cost me? gosh this sux....

Mahjik

iTrader: (1)

You can search the classifieds here for a used one. People are always selling them. A new hi-flo will run you around $330 or so:

http://www.gothamracing.com/catalog/...roducts_id=407

RotaryMaybe

can't use a highflow cat, i just need the main cat

Mahjik

iTrader: (1)

The hi-flo cat is a better buy. It's not a midpipe. The stock cat is heavy and expensive.

RotaryMaybe

No but i can';t use a highflow cat cuz im already running a dp and full catback wiuth the stock ecu...i need to put more restriction on the exhuast putting on the main cat...where's the cheapest place i can fnd a main cat??

Mahjik

iTrader: (1)

A hi-flo cat will provide enough restriction. As long as there is a "cat" there, you will be fine.

If you want to find a stock cat, break out your check book and call here:

Malloy Mazda
1-888-533-3400
Talk to Ray Crowe

Once again, if you want my opinion, get the hi-flo cat.

RotaryMaybe

damn u serious??? crap if a high flow cat is like 3 something bills...how much is a stock cat gonna be??? im trying to find a used one if cheaper as well...this really sux

RotaryMaybe

i have until wed to find one and im in southern cal

RotaryMaybe

guys help me!

Mahjik

iTrader: (1)

A new stock cat is around $1000.