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Boost on Stock FD3S

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Old 01-28-09, 12:52 PM
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Boost on Stock FD3S

Hi Guys,

Just wondering... my car seems to go exceptionally well and actually it seems to be faster than what I expected to be. I think my boost levels are too high. I only changed to twin induction and my boosts goes from 14psi at 4500rpm to 10psi. Is this abnormal and could it damage my engine?

Thanks
Old 01-28-09, 12:59 PM
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The twins can reliable handle 14psi all the time. I did it for about 6 years then went single. Your drop off most likely is caused by your boost control system, be it stock ot other.
Old 01-28-09, 01:00 PM
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Do a search. Boost should read 10psi until arond 4500~ rpm, then 8 psi briefly and back to 10psi. Running 14lbs on stock ecu/fuel system etc can be dangerous.

Although it'd be super odd to drive an FD where the powerband is down low
Old 01-28-09, 01:08 PM
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14 psi on a stock engine and ecu is way to high. you will hit fuel cut at 12.5 psi. so yes, this will damage your engine. we need more info on your mods and what do you mean by you changed to "twin induction" are you saying you only changed the air intake. follow the 10 psi boost rule on a stock FD

Jeff
Old 01-28-09, 01:15 PM
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Originally Posted by jeff p
14 psi on a stock engine and ecu is way to high. you will hit fuel cut at 12.5 psi. so yes, this will damage your engine. we need more info on your mods and what do you mean by you changed to "twin induction" are you saying you only changed the air intake. follow the 10 psi boost rule on a stock FD

Jeff
Hi,

Thanks for the feedback. I have no ECU upgrade... my car is stock.. The twin induction is the air intak e.

I also have a Cat Back but that seems to be it.
Old 01-28-09, 01:28 PM
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search under 10 psi rule. you will find all the answers. 14 psi on your car is going to pop the engine. reduce the psi to 10 and control it until you get an ecu and tuning.


Jeff
Old 01-28-09, 01:53 PM
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Fuel cut boost levels for stock ECU:
Old 01-28-09, 02:07 PM
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Originally Posted by DaveW
Fuel cut boost levels for stock ECU:
I am at sea level and that is exactly how my car is boosting.

So what does that table mean.. do i have to reduce it with ECU.

Regards
Old 01-28-09, 02:10 PM
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Your boost gauge is probably inaccurate - and you really, really need to read the FAQ and search.
Old 01-28-09, 02:10 PM
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Yea maybe check again about your exhaust, if you have CatBack DP and mid pipe, there may not be enough back pressure to keep the boost down to 14 PSI.

That or you may have to bore out the wastegate, so it can let more exhaust by, and you can stay at a constant 10 PSI.

But if your running 14 PSi on stock ECU, i would be careful. 14 is fine on twins but a EMS would be very much recommended. Ie. If you dont wanna blow your engine, get a PFC, if you want to run those boost pressures.

Hope this help, good luck with the Rex.

-Mark
Old 01-28-09, 03:16 PM
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Sounds like you are getting a boost spike when the secondary turbo is coming online. It's not uncommon and it typically happens faster than the ECU will enact fuel cut.

Purchase an electronic boost controller and it will control the spike.
Old 01-28-09, 03:18 PM
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Originally Posted by NastyZ
I am at sea level and that is exactly how my car is boosting.

So what does that table mean.. do i have to reduce it with ECU.

Regards
You may not be seeing fuel cut since there is a delay built in before it happens. Therefore, in the lower gears, it is normal that the boost does not stay that high long enough to trigger fuel cut.

Dave
Old 01-28-09, 03:31 PM
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Originally Posted by Mahjik
Sounds like you are getting a boost spike when the secondary turbo is coming online. It's not uncommon and it typically happens faster than the ECU will enact fuel cut.

Purchase an electronic boost controller and it will control the spike.
Yea a boost controller will only control to a certain point. best bet is to port the wastegate, and get a boost controller.

but if hes getting a EBC, he should get a PFC before that, to make the whole system tunable, and more reliable then just a EBC alone.

-Mark
Old 01-28-09, 03:40 PM
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Originally Posted by Rx72Heaven
Yea a boost controller will only control to a certain point. best bet is to port the wastegate, and get a boost controller.

but if hes getting a EBC, he should get a PFC before that, to make the whole system tunable, and more reliable then just a EBC alone.

-Mark
Creep and spikes are two different animals. If his boost is going back down to 10 PSI before the stock ECU can hit fuel cut (as he seems to indicate), he's just got spike. Creep works basically the other way in which the boost gains uncontrollably and doesn't stop unless your gas foot stops (or you run out of airflow to support increased boost). That doesn't appear to be the situation here.
Old 01-28-09, 04:21 PM
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Yea i completely agree. I got the 2 mixed up there.

But still if hes going as far as getting a EBC, i say get the PFC aswell. EBC without a EMS is rather useless, especially if he possibly would like to keep the 14 PSI Boost, you would need a tunable EMS.
Old 01-28-09, 06:27 PM
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pfc + ebc = $1,500 at least.

first try a different boost gauge, then maybe plop the stock catback back on (maybe even the stock intake box). Run a check on all hoses and lines first as available funds should go into getting the car running right in stock form FIRST, with a 10-8-10 boost pattern, THEN go spend some $$$ on a pfc and ebc.

I would also check the stock restritor pills and make sure they're in place.
Old 01-28-09, 06:33 PM
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Originally Posted by Rx72Heaven
if he possibly would like to keep the 14 PSI Boost, you would need a tunable EMS.
I understand its 1500, and well you could get them all for probably 1000 in the FS section.

And i said IF he would like to stay with 14 PSI then he would need a PFC and EBC to do it reliably.
Old 01-28-09, 07:18 PM
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Originally Posted by NastyZ
Hi Guys,

Just wondering... my car seems to go exceptionally well and actually it seems to be faster than what I expected to be. I think my boost levels are too high. I only changed to twin induction and my boosts goes from 14psi at 4500rpm to 10psi. Is this abnormal and could it damage my engine?

Thanks
Yes, 14psi can damage your engine unless you have supporting mods. Plus, it sounds like you're seeing an increase due to mods rather than what you've chosen to set your boost to. So first, you need to get a boost controller so that you choose your boost rather than reacting to it.

Once you have that, you can consider your fuel, cooling, and tuning capabilities and set the boost to an appropriate level.

Dave
Old 01-28-09, 07:20 PM
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Manual boost controllers + PFC and commander = $850.

Dave
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