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View Full Version : S13 SR just upgraded to gt28rs and wont hold boost need help


Nissan2nr22
04-20-2010, 08:41 PM
So i recently installed a new exhaust manifold and a GT28RS. Everything else is stock except front mount and exhaust. When i drove the car it boosts to 16 psi and then cuts fuel at around 4k-4.5k rpm. I looked online and I believe the stock actuator is supposed to be 6psi. I now put in a boost controller(greddy e-01) and it still doesn't hold boost if i set it for 10psi or anything. It does exactly the same thing and I cannot go past 4.5k rpm unless i barely give it gas so its not going into boost. Can someone help me figure out why its overboosting and wont let me set a lower boost?

jspaeth
04-20-2010, 09:25 PM
So i recently installed a new exhaust manifold and a GT28RS. Everything else is stock except front mount and exhaust. When i drove the car it boosts to 16 psi and then cuts fuel at around 4k-4.5k rpm. I looked online and I believe the stock actuator is supposed to be 6psi. I now put in a boost controller(greddy e-01) and it still doesn't hold boost if i set it for 10psi or anything. It does exactly the same thing and I cannot go past 4.5k rpm unless i barely give it gas so its not going into boost. Can someone help me figure out why its overboosting and wont let me set a lower boost?

Are you on stock MAF?

Also, you probably have the wastegate and/or boost controller lines hooked up wrong.

Nissan2nr22
04-20-2010, 09:39 PM
Are you on stock MAF?

Also, you probably have the wastegate and/or boost controller lines hooked up wrong.

Yeah stock maf, and i had it wastegate to intake manifold and it did exactly what its doing now with boost controller and i know its hooked up correct i've had it on before with the t-25 and it worked perfect.

obsolete
04-20-2010, 09:59 PM
Shouldn't it be wastegate to hotpipe/comp outlet?

slider2828
04-20-2010, 10:01 PM
What injectors are you running? Also search for a thread I created about Profec boost controllers, will tell you how it works....

jspaeth
04-21-2010, 10:13 AM
Yeah stock maf, and i had it wastegate to intake manifold and it did exactly what its doing now with boost controller and i know its hooked up correct i've had it on before with the t-25 and it worked perfect.


Wrong. It is wastegate to hotpipe. You may have torn the diaphragm on the wastegate actuator by exposing it to vacuum.

IIRC, someone else has had this happen....the diaphragm is not meant to be exposed to vacuum (seen in intake manifold).

The wastegate acutator should be hooked up only to a boost source (hotpipe or compressor outlet).

Nissan2nr22
04-21-2010, 01:42 PM
Oh ok i got it, yeah i guess now that i dont have the outlet and inlet pieces i have couplers instead. I dont have an outlet for the wastegate hose. What should i buy to fix this problem?

Om1kron
04-21-2010, 02:28 PM
the turbo doesn't have a nipple on the compressor housing that looks like a hose goes to it?

normally that goes straight to the wastegate, someone correct me if i'm wrong.

japslapsilvia
04-21-2010, 04:23 PM
you can also source boost from TB. the nipple on the bottom is before the TB plate. so it will only see boost.

fliprayzin240sx
04-21-2010, 04:25 PM
If you had just the actuator hooked up and it was hitting 16 psi, then the actuator is either adjusted too tightly or its fucked up. Get an air compressor and try to see how many psi it takes for it the actuator to open up.

renegade_ewok
04-21-2010, 04:27 PM
Yeah stock maf, and i had it wastegate to intake manifold and it did exactly what its doing now with boost controller and i know its hooked up correct i've had it on before with the t-25 and it worked perfect.
Did someone miss this? He is on stock MAF.

Let's address the stock maf issue first before he blows his motor by going lean.

It sounds like you need...

1. Z32 MAF
2. Boost controller hooked up right
3. Tune

obsolete
04-21-2010, 05:37 PM
yea but you could still boost 7psi with stock maf. his wastegate is hooked up wrong as stated above. if you just have a coupler, you could buy or fab something like the frsport quicktap.

Turbo Quick Tap Fitting for Boost Source (http://www.frsport.com/Turbo-Quick-Tap-Fitting-for-Boost-Source_p_7854.html)

KoukiMonsta
04-21-2010, 06:36 PM
the turbo doesn't have a nipple on the compressor housing that looks like a hose goes to it?

normally that goes straight to the wastegate, someone correct me if i'm wrong.

yes, but not all turbos have this nipple.

Did someone miss this? He is on stock MAF.

Let's address the stock maf issue first before he blows his motor by going lean.

It sounds like you need...

1. Z32 MAF
2. Boost controller hooked up right
3. Tune

was waiting for that lol. but yes it will be fine for 7 psi.

get ur boost controller hooked up correct(or just your wastegate for that matter) Test actuator via compressor as i too have heard vacuum fucks the diaphram.

then get back to us.

Nissan2nr22
04-21-2010, 11:37 PM
Found the problem thanks everyone. Yeah i just need to use the quicktap thing to have a nipple on the coupler on my hotpipe. I had it running wastegate to the intake manifold which is wrong. I'm definitely upgrading injectors, maf, and tune very soon i just wanted it to run on stock boost for a little so I can get the funds right.

kikcaffine
04-23-2010, 12:07 AM
Found the problem thanks everyone. Yeah i just need to use the quicktap thing to have a nipple on the coupler on my hotpipe. I had it running wastegate to the intake manifold which is wrong. I'm definitely upgrading injectors, maf, and tune very soon i just wanted it to run on stock boost for a little so I can get the funds right.


I thought the 28rs came with an adjustable w/g? Couldnt afford injectors but bought an e-01? Priorities my friend, priorities.

Nissan2nr22
06-02-2010, 10:51 PM
Ok so i got the quick tap and installed it and the boost controller reads perfect and everything. It still overboosts but not as bad. I'm pretty sure the diaphragm in the wastegate is messed up so i ordered a new stock actuator. Hopefully after all this I can run at 7psi and then save up for z32 maf, injectors, and a tune. Thanks everyone.