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Boost issue (not going over 7 psi)

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Old 12-27-07, 03:44 PM
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Boost issue (not going over 7 psi)

I just wanted to share this. Maybe it'll help someone with the same issue...

My car has minor mods and boosts up to 15psi. Turbo back exhaust, reflashed ecu, mazda competition radiator, and upgraded compressor wheels. But about 3 weeks ago it was not boosting past 7 psi. I checked the restrictor pills, some of the visible vaccuum lines, and switched out three reachable check valves with viton check valves, but I still had the issue. Thanks to Sergio's (Norbak1258) guidance, I found the culprit. My lower intercooler pipe had a gash on the side (pics attached).

Yesterday, I bought a metal pipe with a 90 degree bend from RMCR Performance to replace that rubber lower pipe attached it with rubber joiners. It works great now. Back to 15 psi. I'm just relieved it wasn't something more involved and expensive as switching out solenoids or doing the whole vaccuum hose replacement (which I plan to do in the near future, anyways). I know many of you know this but posting this up with pics should help reinforce the fact that a boost problem can be as simple as this...
Attached Thumbnails Boost issue (not going over 7 psi)-lower-intercooler-pipe.jpg   Boost issue (not going over 7 psi)-lower-intercooler-pipe2.jpg  
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Old 12-27-07, 03:49 PM
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Yup I had the same issue a while back...

https://www.rx7club.com/showthread.p...highlight=tear
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Old 12-27-07, 03:54 PM
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Oh, damn! I did a lot of searching and didn't run into this thread. Maybe the title through me off...
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Old 12-27-07, 03:58 PM
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It almost looks like the slit was created from a cut from a knife or something sharp, so how did the pipe get cut with that slit? Normal boosting couldn't cut it like that, could it?
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Old 12-27-07, 04:00 PM
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Originally Posted by Legna00 View Post
Oh, damn! I did a lot of searching and didn't run into this thread. Maybe the title through me off...
I don't think it is a bad thing this was posted again. It increases the chances of helping out fellow FD owners.
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Old 12-27-07, 04:00 PM
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Originally Posted by MrNizzles View Post
It almost looks like the slit was created from a cut from a knife or something sharp, so how did the pipe get cut with that slit? Normal boosting couldn't cut it like that, could it?
Yup, split from boost over time.
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Old 12-27-07, 04:04 PM
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To be honest, I'm not sure how this happenned. Was yours cut with something? I think it could be possible for it to break like this since there has been lots of heat and boosting throughout its lifetime. Could be wrong though. I'm still a newbie when it comes to FDs, but so far I've been able to work on the issues without going to a mechanic.
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Old 12-27-07, 04:05 PM
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Originally Posted by Legna00 View Post
To be honest, I'm not sure how this happenned. Was yours cut with something? I think it could be possible for it to break like this since there has been lots of heat and boosting throughout its lifetime. Could be wrong though. I'm still a newbie when it comes to FDs, but so far I've been able to work on the issues without going to a mechanic.

They split from the pressure. Over time the rubber gets weak until one day they split.
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Old 12-27-07, 04:11 PM
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hey man if you need a replacement tubing I got one for sale. (I know this isn't a for sale section but just trying to help)
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Old 12-27-07, 04:13 PM
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I'm good, DMoney. Thx anyways . After a days long search I was able to get a replacement from a local speedshop.
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Old 12-27-07, 04:18 PM
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very nice
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Old 12-28-07, 02:45 PM
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Here's how it turned out...

Upload failed. I'll try again when I get home...
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Old 12-28-07, 03:15 PM
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So what's a good aftermarket pipe to replace this rubber pipe with?
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Old 12-28-07, 08:01 PM
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i still can't understand why mazda put such a small i/c and cheap rubber pipes in the car...they could have easily installed metal pipes to prevent this
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Old 12-28-07, 08:30 PM
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You better keep the busted IC pipe on there if you are running 15psi on teh stock injectors. They hit 100 duty cycle somewhere around 13-14 psi with a proper tune. With a reflashed ecu you are living on borrowed time. I wouldnt do too many 4th/5th gear pulls if I were you.

Seriously your car is a ticking time bomb with 15psi on the stock injectors. If you have a standalone and 1300 secondaries then continue on and ignore my post.
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Old 12-28-07, 09:25 PM
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Originally Posted by NTIMD8 View Post
They split from the pressure. Over time the rubber gets weak until one day they split.
Exactly! I had the same issue, with low boost. Checked out the lower IC hose and I had the EXACT same splits in the hose.
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Old 12-29-07, 12:26 AM
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Originally Posted by djseven View Post
You better keep the busted IC pipe on there if you are running 15psi on teh stock injectors. They hit 100 duty cycle somewhere around 13-14 psi with a proper tune. With a reflashed ecu you are living on borrowed time. I wouldnt do too many 4th/5th gear pulls if I were you.

Seriously your car is a ticking time bomb with 15psi on the stock injectors. If you have a standalone and 1300 secondaries then continue on and ignore my post.
Am I not actually pushing about 12 psi of absolute pressure rather than 15 psi like the gauge says since I'm at 6,200 ft above sea level? This is what a friend told me. He practically lives on this website, lol. I'll definately read more on this, though. Thanks!

This is how it looks with the new setup. I painted the tube black with High heat resistant paint.
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Old 12-29-07, 01:24 AM
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Old 12-29-07, 10:41 AM
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Originally Posted by Legna00 View Post
My old roommate, a member of this forum, used to run the pettit unlimited ecu with all the boltons. He didnt remove teh boost pills nor did he port his wastegate. The car constantly ran at 15psi, it sure was a blast to drive, well unless you count the 3 motors that blew within 18k miles

Take my advice for what it is, I bought plenty of blown motor cars with rechipped ecus and PFCs on the stock map that the previous owner was running 14-15psi. Maybe it was all coincidence, but when motors are failing with 10k miles or less on them(blown apex seals) while running 14-15psi on the stock injectors that is enough to tell me it is a no no. Obviously there could be other issues in these setups, but it all points to no enough fuel.
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Old 05-03-08, 10:21 AM
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Where i have to look esactly to check this pipe on my fd? i have to rise the car on a bridge and look below??
i have the same problem i guess, some times i bosst normally and other time i don't
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Old 05-03-08, 11:25 AM
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Nope, just open the hood and remove the pipes behind the intercooler.

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Old 05-03-08, 12:03 PM
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Originally Posted by djseven View Post
Obviously there could be other issues in these setups, but it all points to no enough fuel.
I just re-read this post and saw this last sentence. My car is running very rich at this time. I had it dynoed in September 07, and since then, I have yet to install anything to increase power. The ECU was reprogrammed by XS engineering to run this way by the first owner of the vehicle after he modified it. I have been advised that running it rich can be detrimental in time, but it is, of course, better than running it lean. I do plan to get a PFC in the near future. Pictures of the dyno sheets are attached.
Attached Thumbnails Boost issue (not going over 7 psi)-picture-002.jpg   Boost issue (not going over 7 psi)-picture-003.jpg  
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Old 06-27-08, 02:33 PM
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since this is a boost thread what does it mean when they say to make sure you are having 10-8-10?
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Old 06-28-08, 01:14 AM
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Arrow

Originally Posted by Frankie_FD7 View Post
since this is a boost thread what does it mean when they say to make sure you are having 10-8-10?
http://fd3s.net/boost_test.html
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Old 06-28-08, 09:59 AM
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I watched my FD on a dyno with stock IC piping and the way they swelled up , i thought that they were going to pop... but instead... the stock intercooler actually cracked/seperated....

ouch..
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