2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

VERY high boost...

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Old Jan 4, 2004 | 12:53 AM
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VERY high boost...

hey guys i just got my TII not too long ago, and im not up to date on everything... heres the specs -

right now its got a jspec motor with no emissions, manual rack, TID mod w/filter, DP, MP, HKS catback, RB FCD, and thats about it engine wise...

at WOT it boosts up a little past 15 psi... and i know this is very bad and i never let it get there anymore after i found out, but my question is what are the most critical things i need to do to either get it to be able to support that boost, or how to bring the boost down...

i HAVE searched and know the basic things i need to do, but what i also found out is... when im going through the gears just driving and decide to get on the throttle the boost creeps up to about 15 and all the power just goes away, and the motor struggles. what causes it to do this? and my next question below is pretty much how can i fix it, so i can get on the throttle through all gears.

i know one of the things i need to do is port the wastegate to bring it down, and get a walbro, but which is more important? and is there anything else i need to do...

thanks
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Old Jan 4, 2004 | 02:03 AM
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Perhaps a boost controller.

where in Torrance are you located?
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Old Jan 4, 2004 | 02:07 AM
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near north high school...
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Old Jan 4, 2004 | 02:14 AM
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kool, near sir la brea park. Maybe we shoul meet a torrance crossroads some time.
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Old Jan 4, 2004 | 02:17 AM
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yeah i was just talking with another member on here today in person about getting a meet together, there seems to be more and more FC's around torrance now days...

can anyone help me with my problem though?
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Old Jan 4, 2004 | 02:45 AM
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15PSI on stock fuel system would be dangerous. I'd suggest not driving the car until you have at the very least an upgraded fuel pump and a ported wastegate
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Old Jan 4, 2004 | 02:47 AM
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its only dangerous if i boost that high, which i dont...
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Old Jan 4, 2004 | 02:52 AM
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Originally posted by deltr0n`
its only dangerous if i boost that high, which i dont...
Hate to say it, but whats the point? You can't go WOT in 3rd or 4th? why drive?

The ONLY things you can do to to lower the boost are; restrict the exhaust or intake flow, or port the wastegate. You have no other options to lower boost.

-Robert
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Old Jan 4, 2004 | 02:54 AM
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thats why im trying to figure out how i can fix it... im going to replace the fuelpump within the week, i just want to know for sure... if no one helps me ill find out for myself...
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Old Jan 4, 2004 | 03:09 AM
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Originally posted by deltr0n`
thats why im trying to figure out how i can fix it... im going to replace the fuelpump within the week, i just want to know for sure... if no one helps me ill find out for myself...
I just said above the ONLY ways you can fix it.

A. Restrict your intake (put the stock airbox in)
B. Restrict your exhaust (inatall a cat)


Plan A, and Plan B. are not 'good' solutions but cheap/easy ones. You will loose power, and there is no garantee it will stop all your creeping.

Plan C. Port the wastegate, remove the turbo and port it, or have it ported. Do a search there is 3000 threads on it.

Plan C. is the best permanent solution to fix it right.


Plan D. add fuel, a fuel pump alone is NOT enough to hold 15 PSI, you need additional injectors, a fuel pump, and a fuel controler at the least.

That being said .. Plan D is not a good sultion either, without first impementing plan C. ... Your are getting what is called creep. More boost than your wastegate can bleed off. Even if you are suplying enough fuel creep is not good. It is too unpredictable, and uncontrolable. Get a cold day, or a freeway onramp and you go boom.


Fix it,

Port the wastegate. Then buy a boost controler and set the boost to a good safe level based on your fuel system.


Look at my Mods below, and I won't dare run 15 PSI.. you are a ticking time bomb right now.

-Robert

Last edited by Rpeck; Jan 4, 2004 at 03:16 AM.
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Old Jan 4, 2004 | 03:26 AM
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thank you, thats exactly what i wanted to know... how about a FPR? like the one here any advantages of getting this?
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Old Jan 4, 2004 | 03:38 AM
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Originally posted by deltr0n`
thank you, thats exactly what i wanted to know... how about a FPR? like the one here any advantages of getting this?
Thats up too you .. alot of other things I would do first, thats over kill for your current setup. I still don't run a FPR, nor do I plan too.
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Old Jan 4, 2004 | 07:37 AM
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Isn't overkill good though for the FPR....? At least he'll never have to touch it and it'll still do the job on a stock TII if need be.

And how do you get away with no FPR...? I'm not knocking it just want to understand more.... Doesn't the secondary MAZDA fuel rail have one from the factory...?
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Old Jan 4, 2004 | 10:29 AM
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the first question that should be asked here is what guage are you judging boost by? The stock one, or an after market one? Do you have a FCD?

yea port the wastegate, and put in atleast a 3rd gen fuel pump and youll be fine.

-Chris
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Old Jan 4, 2004 | 01:46 PM
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Originally posted by chris-reedtn
the first question that should be asked here is what guage are you judging boost by? The stock one, or an after market one? Do you have a FCD?

yea port the wastegate, and put in atleast a 3rd gen fuel pump and youll be fine.

-Chris
Good point, I assumed he was accurate on his "amount of boost" statement. He says above he does have a FCD.
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Old Jan 4, 2004 | 01:47 PM
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yeah i got a autometer boost gauge, and an RB FCD... how hard is it to port the wastegate yourself? i was just going to take it in to jeff at rotary power here in gardena to have him do it.
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Old Jan 4, 2004 | 08:09 PM
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thank you, thats exactly what i wanted to know... how about a FPR? like the one here any advantages of getting this?
This fuel pressure regulator will do nothing for you. The only way a fuel pressure regulator can add fuel to your engine is if it is a Rising Rate Fuel Pressure Regulator (RRFPR). For example:

http://www.bellengineering.net/fmu2020.html

Having lived with boost creep long enough to blow two engines before I became smart enough to port my wastgate I can tell you - Rpec is correct. Port your wastegate before it is too late.

Of course it is much easier to get the turbo off when you change your engine, so you may want to wait!
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Old Jan 4, 2004 | 10:18 PM
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If you have to drive before you can remove the turbo/port wastegate or replace turbo/manifold/lines w/ ported '89 TII stuff-

Restrict the intake. I found this was a better compromise than restricted exhaust. You still get the hard fast spool-up, it just poops out on the top-end a bit.

Wrap that cone filter in duct tape untill your boost creep is under control.

I too lost an engine due to boost creep! Don't let it happen to you...
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Old Jan 4, 2004 | 10:22 PM
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what about something like an HKS EVC4? it has an offset feature that will cut down boost if you are creeping or not reaching your desired boost to match your preset level.
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Old Jan 4, 2004 | 10:25 PM
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that RRFPR looks and sounds much better, do you have any experience with it, or does anyone else?

i was thinking about just porting the wastegate myself, it shouldnt be too hard to take off the turbo unless its on there really good like some people, becuase i have nothing in the way really with my jspec...
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Old Jan 5, 2004 | 01:29 AM
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I do not think a boost controler made by anybody would solve this problem.

If the waste gate cannot control the boost than nothing can stop it. The reason it is overboosting is because the wastegate hole is not big enough to by pass the exhaust. If the hole is not big enough there is not much you can do. Except what has been suggested before.

James
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Old Jan 5, 2004 | 03:09 AM
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doh nevermind.
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Old Jan 5, 2004 | 06:03 AM
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turbo solution

best thing you could do for a 'complete' fix is to get a reprogrammed e.c.u.
get one that has upgraded the following areas:
a/f ratio + injector pulse
has reset boost limit to 10 or 12 psi
has no fuel cut
has no speed limit
has no rev limit

you should also get a good aftermarket boost gauge.
the above items should solve most of your car problems with boost, detonation, leaning, etc.

i currently have a 1990 t2 with about 325rwhp.
the only things NOT stock are the:

exhaust - racing beat full race
ecu - fully reprogrammed by progress
air filter - k/n
radiator - koyo

that's just the engine/power mods.
i also run a boost of 1bar/14psi.

hope that helps and good luck

john
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Old Jan 5, 2004 | 06:34 AM
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Originally posted by 85TIIDEVIL
Isn't overkill good though for the FPR....?
The stock FPR can flow enough fuel for ~400hp before it bocomes too much of a restriction. Unless you're planning on making that much power, it's not just overkill, it's a waste of money.
And how do you get away with no FPR...? I'm not knocking it just want to understand more.... Doesn't the secondary MAZDA fuel rail have one from the factory...?
He meant no upgraded FPR. All EFI engines have a FPR.
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Old Jan 5, 2004 | 09:59 AM
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i just put a fpr on my car and it has made it run so much better it's insane.
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