Montego

iTrader: (1)

Rynberg,

I am thinking that chances are his wastegate is ported. The dude didn't even know he had an upgraded fuel pump. What's to say his WG isn't ported since they guy who sold him the car set it down to 8 psi.



because as many people have told you: If you don't have a ported wastegate and run an open exhaust your car will experience creep. Since you never stated a ported WG, 8 psi = boost leak.

Trevrx

I think some of the guys are wrong on this one.

I have a de-cat pipe, intake, cat back, IC hard pipes, and my boost controller easily holds boost at 8 psi as a minimum if I want it to. There is deffo not a boost leak either.
I have been running at 11.5 psi for the last 20k miles with no probs, everything else as standard.

GoodfellaFD3S

iTrader: (213)

You're saying that I'm wrong? Do you still have a catalytic converter on the car? Are you still running factory twins with the factory wastegate?

G's 3rd Gen

iTrader: (11)

They are not wrong. Some opened cars are able to handle boost better than others. You are still going to get creep w/ no restrictrion. I've never not seen that. I would still say the non set up has a ported wastegate. What the hell is a de cat pipe? Does thast mean you still have a factory downpipe then??

Trevrx

I'm not saying you're wrong in your experience no.

My rex was standard when I bought it, so I removed the cat and replaced it with a straight through stainless steel pipe. The back box is a veilside stainless steel silencer. The intake box has been removed and replaced with a re- enimya(sp) cone with heat shields. The plastic IC pipes are now aluminium.

When I first did these mods I didn't have a boost controller, so the boost spiked horrendously at 4.5k rpm and crept to over 1 bar at wot.

I know there should be a fuel cut at those figures, but I've checked the ECU and it's standard. So maybe a fuel cut defender is fitted, but I can't see it if it is!

Anyway, I fitted an HKS boost controller and on low setting it now holds at 8psi, but I have run it at 11.5psi for the last 20k miles with no probs. I also use a 100/1 premix oil at every fill up, and service every 3k miles.

fendamonky

iTrader: (6)

I believe America was the only country to recieve RX-7's with a pre-cat, so factory DP or not shouldn't make any difference for Trevrx.


Trevrx: Is your car street legal in the U.K. with your exhaust like that? I thought noise level was a major concern when it comes to registration and MOT in England.. I only ask because I will be moving to Huntington/Cambridgeshire in January. I was told that I would need to get silencers before I considered shipping my 7 over from America..

Guys: Does the fact that Trevrx has a boost controller installed make much difference in comparison to the treadstarter who only has a PFC?? ...I was under the impression that with a boost controller you could manually control your boost levels (without leak or creep/spikes).. kinda the whole theory of "hey, I think I will limit my FD to 3psi before I let this valet get in my car.."

Then again, I'm just a newbie.. so I dont know what I'm talking about.

GoodfellaFD3S

iTrader: (213)

I have posted this a million times before, but I don't mind doing it again :

an electronic boost controller has no effect on keeping boost creep in check, which is a mechanical phenomenon.

Trevrx

Hey Fendamonky. The UK RX-7's are fitted with a pre-cat too, but they're very rare as Mazda only sold 124 FD's believe it or not in this country!

The vast majority over here are imports from Japan which are right hand drive too and don't have a pre-cat as you rightly say.

Yes my car is street legal over here, but it depends on the year of your car as to whether it will pass the MOT test or not with the CAT removed. Basically, if it's registered before July 31st 1995 then it will pass the emmissions test with the cat removed, but if it's registered after that date you will have to fit the cat back on to pass the MOT. Noise level doesn't really come into it, there are lots of TVR's etc over here that are louder than my car.

As for the boost controller, all I can say is it works perfectly on my car. It's an HKS EVC, but you will never limit boost to 3psi with it. Switching it off is the same as the lowest setting and holds boost at 8psi. HTH

Btw mine is a Jap import.

Monsterbox

iTrader: (6)

let me share my story

a few weeks ago i opened up the car...added hks intakes, resonated midpipe onto my 3 inch dp the exhaust system is basically straight through except the CB is the stock piping but witha straight through muffler on it so straight through as in 3inch to 2.5 at the end

well i had MAJOR spikingl...15, 16lbs BAD....so i simply unplugged the wastegate and precontrol solenoids cured it completely...i could pull to redline with 7psi and the only creep i could see was maybe .5 to 1 lb in FREEZING weather near redline

through a Profec B Spec II on two nights ago....i keep having to turn up the duty cycles as i CAN'T get the car to reach 12lbs the max its hit in 4th gear is 11.7 so far

rynberg

If you can't raise boost to hit 12 psi with a controller, you have blown turbos or a boost leak. Period. A FEW people have gotten away with running a full exhaust with minimal creep. 95% of cars don't.

matty

your patience and rynberg's is quite amazing. of course i havent finished reading the thread yet.

i on the other hand must remain silent on this one.

NeoTuri

iTrader: (2)

I personally don't trust electronic boost controllers and have tried adjusting boost with the PowerFC with little effect.

Instead, I just pulled the solenoids and replace them with a manual controller. Result: predictable boost.

Nevertheless, I doubt I could keep it under 10psi with a full 3" exhaust, though, unless I had ported the WG or used a blow-off valve (which is bad since you are still overdriving the turbos).

Montego

iTrader: (1)

so you have a stock catback?


I had MP,DP with a stock CB. I spiked so I got an EBC. Then I changed to a magnaflow CB. No change as far as boost control went. Next, I bought a RB catback because I could not stand the magnaflow. The result was instant creep, which as Rich said the boost controller does not do **** for that.


For the people that claim that their car does not creep on stock turbos: Your exhaust system has restriction or your wastegate is ported.

dubulup

These threads are always fun

Mahjik

iTrader: (1)

The PFC isn't technically an "Electronic Boost Controller". While it can control boost, its limited to using the stock boost control system to do so. If your stock system is already haven't problems controlling its boost, then the PFC alone isn't going to help.

This is where a manual or "real" EBC can fix the problem.

NeoTuri

iTrader: (2)

Understood.

My dyno guy mentioned once that quite a few people come rolling in with expensive EBC's and still can't control boost properly.

Mahjik

iTrader: (1)

That is correct. EBC's can't control boost creep. That problem is a limitation of the wastegate size which is why only wastegate porting or exhaust restriction will help in that situation, regardless of what boost control method you are using.

There is more to controlling boost than just getting a boost controller.