beqa16v

is this dangerous? my car overboosts to 11.2, sometimes 11.5 before secondary transition. i dont see this boost on my gauge, only boost controller memorizes it as peak boost, i guess that happens instantly for about a tenth of a second. my mods are listed below.

Oliv

Given your open intake and exhaust it's normal.
11.5 is not alarming in my opinion.

RotorDream

I'm guessing if your running a high flow cat, you also have a DP, slight overboost is common if your running as open an exhaust as you are. 11.5psi shouldnt cause to much of a problem, the stock ECU can handle up to 12psi, but if your really worried about it throw the stock cat back on and it should solve your problem. if you get up to 11.8/11.9 i would deffinatly throw the stock cat back on then

beqa16v

downpipe is stock JDM (withought precat i guess). i didnt put those mods on my car, it arrived from japan this way. i always read here that going past 10psi on stock ecu is dangerous.

DaveW

Stay below these and you'll be OK.

Dave

RotorDream

constantly going over 10psi is bad but not necessarely deadly, try and take it easy on the pedal and you should be alright (trust me i know its hard! try breaking in a rebuild)

you really have 3 options to solve the problem. throw a stock cat back on to increase exhaust resistance, aftermarket ecu, or port your wastegate.

4CN A1R

iTrader: (6)

you really should really get that boost under control. all it takes is one cold night. you could overboost, hit fuel cut, and essentually blow the motor or chip an apex seal.

i am funning full exhaust and intakes right now and i am keeping my boost at or under 10psi. with slight boost creep in really high 3rd gear.

beqa16v

hoses for boost controler solenoid had too small internal diameter. i replaced them with bigger diameter hoses, thought they might have caused bleeder valve effect but nothing changed. i guess i'll have to port the wastegate. is this difficult? can i do it myself? do i need to take off a lot of things?

R-R-Rx7

iTrader: (24)

i would recommend to get a power fc and get a proper tune for that boost

beqa16v

boost only jumps of about a second then falls back to 10psi again. at rpms above 6500 it gradualy reduces to 8psi

4CN A1R

iTrader: (6)

porting the wastegate is for solving a boost creep issue; not overboosting. a boost controller is the solution. i believe you stated you had one. you must have some vac or boost controller related issue. are you sure the conroller is working properly. also, is the controller feeding from the same source as the boost gauge.

beqa16v

Boost controller is feeding from the same source as the boost gauge. You say i might have some kind of vac issue. what type of vac. issue? leak somewhere? or wrong connection. tomorrow i will remove the controller and place a regular hose between primary turbo and wastegate actuator and see what happens.

4CN A1R

iTrader: (6)

what kind of controller do you have.

no need to swap the hose out. if you turn off your controller, your boost should read 7-8psi. you are having the same problem as i right now. my controller when off reads the same as when on. when i find out my problem...i'll fill you in

real1st

iTrader: (3)

That doesn't appear to be that big of a problem. You could try putting the stock cat back on, or maybe an ecu upgrade. How is the car working other than that? Lets hear some information on the car. Year, Mileage,Pics? Always interested.

dhays

iTrader: (1)

I'm running in to the same problem occasionally. Of course I'm just going off of my boost guage, but I'll hit between 11-12 in primary if the weather is cool. I'm just about at sea level. I have dp, hi-flow cat, cb, and greddy intake. I'm on stock ECU but have been thinking about moving to a Pettit Unlimited ECU or possibly going with a PFC. Would the Pettit protect me from the occasional 11-12 boost levels?

4CN A1R

iTrader: (6)

if you get tuned for that amount of boost

Mahjik

iTrader: (1)

Guys, let's NOT confuse boost control with aftermarket ECU's. They are two separate concepts. The people that say "Get a PFC" for boost spikes are providing the wrong information. While you can tune the car to deal with the increase, that's NOT fixing the real issue of controlling the boost. Say you tune for that little extra spike; what happens when you do a few more flow mods and the spike gets bigger? A lost engine is what....

Before anyone says "the PFC can control boost", it can still have the same problems as the stock ECU since it uses the same solenoids to control boost.

Fix the real problem, controlling the boost. Use some sort of boost control whether electronic or manual. I recommend spending the extra money and using an electric boost controller. They are all good, so pick the brand that has the options you want/need.

dhays

iTrader: (1)

I'm slow, so my thinking is this way. If I were to get a flashed ECU that was mapped for intake, cb, dp, and hi-flow cat then wouldn't it handle the fuel requirements up to it's boost limits? So, I'm not thinking that a Pettit Unlimited ECU would limit boost, but that it should be able to manage the fuel/air mix required for the boost spikes that I'm getting of 11-12 psi. Am I missing something again? I don't plan on making any further flow mods to my FD. I've heard that the stock ECU should be able to handle boost up to 12 as far as fuel/air mix but I'm doubtful.

I do like the idea of a EBC. I'm looking at some options now. I'd like to be able to be sure that I didn't boost over 10 regardless of how cold a day it is.

Mahjik

iTrader: (1)

For starters, the Pettit ECU is not flashed for your specific mods. Pettit has ONE map which ALL their ECU's run. They have two flavors which are Limited and Unlimited. Basically, that's just fuel cut. Limited as fuel cut at 14.7 PSI, unlimited, well is as it says so no fuel cut.

Here's the problem with your logic:

* If you are spiking, your boost is not under control of the current boost control system. How long or when will the spike go higher? You don't know and that's the problem. While you can just add more fuel, that's not really fixing the problem. That's adding a really bad band aid which may cost you a motor. Is it really worth that?

If you want to keep your car reliable, fix what the real problem is which is the boost control.

The stock ECU has parts in the map, mainly around the transition of the twins, which allows higher than 10 PSI. Mazda accounted for a little spiking in that area in their programming. However, the stock ECU is not meant to run 12 PSI through out the entire rpm band.

beqa16v

I have electronic boost controler my car is JDM 95 FD with 42K miles on it.

found it on ebay, this is what i have. do these things work?
http://cgi.ebay.com/ebaymotors/Elect...spagenameZWDVW

dhays

iTrader: (1)

OK, I think I understand that. Essentially, the Pettit ECU simply has a map that can account for an increase in flow (over the stock ECU) up to a certain point.

So it is back to the idea of an EBC. I think I understand what you are saying and it makes a lot of sense. I was thinking about an Apexi AVC-R. Probably overkill for both me and my build, but it seemed to offer some flexibility.

It may be the best option would be to look at boost control first, then look at the possibility of another ECU, either something like the Pettit or a PFC. For my purposes and my build, I'm thinking the Pettit may make the most sense.

Again, thanks for the information.

Mahjik

iTrader: (1)

Yes, the AVC-R has a lot of options. Keep in mind that all those options can also make it a nightmare to configure. I've never messed with one in sequential operation, but a friend of mine had one for his non-seq setup.

Yep, boost control first, then ECU. That could change if you go the PFC route as the PFC has a boost control kit which can be purchased separately. However, if the Pettit ECU will be your choice, a nice EBC will work well.

beqa16v

so is it safe to assume that around 12psi boost spike somwhere between 4500-5000 is safe?

Mahjik

iTrader: (1)

IMO, no. While the stock ECU may account for it, it still indicates that your boost is not properly under control.

beqa16v

you are right, i'm not giving up on solving this spike issue. today i removed controller solenoid and installed a hose withought restrictor in its place, i only left the head unit to monitor peak boost. withought restrictor i got 8psi peak, gradualy falling down to 6.5psi at high RPMs. this means its a boost controller issue. i will put a bleeder valve for a while. I dont like that boost looses 1.5psi on the top end i thought it shouldnt do this way with exhaust, high flow cat and filters