Max Boost on a T28 s14 sr20det

[shift_SRDETuser]

I have a sr20det s14 swap package and looking at aftermarket boost controllers-- I am wondering what is the max boost level that the t28 s14 can handle?

I did search and found nothing on the max boost levels for a s14.

[ProjectX001]

Don't quote me on this but I believe I read before that 11-12 PSI is safe...that's like bare minimums without any tuning or changing around parts they also rate it to creat 230-250 RWHP on that stock boost..

[shift_SRDETuser]

stock boost is 11 psi... I am asking about the max boost levels and the horsepower associated with those levels before you have to add more fuel or tuning. Basically the largest amount of boost the stock tune and fuel system with handle. I had heard 20 psi but am not sure?????

[ProjectX001]

stock boost is 11 psi... I am asking about the max boost levels and the horsepower associated with those levels before you have to add more fuel or tuning. Basically the largest amount of boost the stock tune and fuel system with handle. I had heard 20 psi but am not sure?????

I think you good sticking in the 18-20 psi max out of that turbo i've seen small VW GTI stock turbo at maximum and i mean maximum tuning boost 21 PSI i would say you can safely say any where from 18-20PSI out of it tho!

[redtop91]

You should learn to read a compressor map and look up the compressor map on http://www.turbobygarrett.com and it will tell you all you wanted to know, and even some stuff you didn't know you wanted know, about the turbo.

[shift_SRDETuser]

I found the answer on zilvia -- that is some crazy mathematical based stuff on turbo garretts website. The max pressure is 1.2 bars or 17.5 psi or so. That should be good for roughly 300-320 hp which is about all I want for the street and strip use anyway. I plan on running A/C cause it is hot in my state.

You got to love those sr20dets. I can not wait till mine is done-- thanks...

[BoBa524]

stock boost is 11 psi... I am asking about the max boost levels and the horsepower associated with those levels before you have to add more fuel or tuning. Basically the largest amount of boost the stock tune and fuel system with handle. I had heard 20 psi but am not sure?????

huh? i'm running a completely stock s14 sr and it boosts to 7psi max.

[shift_SRDETuser]

then you do not have an s14 (sr20det) or have another turbo on it? Stock s13s have a t25 / .86 diameter for more high end torque pushing 7 psi or .5 bar. The s14s have a t28 / .86 diameter and push 1 bar or 11-12 psi. Check out wiki or any other source. There are differences between the 95-96 s14s (sr20dets) and the 97-98 s14s (sr20dets).

Do you have the boost turned down?

http://en.wikipedia.org/wiki/SR20DET

[redtop91]

huh? i'm running a completely stock s14 sr and it boosts to 7psi max.

Bad wastegate spring or the boost restrictor is still in place.

[shift_SRDETuser]

Bad wastegate spring or the boost restrictor is still in place.

I am by no means an expert -- but how could it be the wastegate? Are they not internal which means they are not adjustable anyway? What is this restrictor that you discuss?

[redtop91]

You can't adjust a wastegate but if the spring is bad/seized the wastegate won't work properly. Wastegate actuator spring is what I should have typed. On S13 SR's there is a restrictor in a vacuum hose to the boost solenoid that restricts boost to 7 PSI. When it is removed, boost jumps to 10-11.

[jr_ss]

Both you guys are wrong, Boba is right. The stock boost is 7psi on the S14 sr. The boost pressure did not change from the S13 Sr to the S14 Sr. The only way to increase boost on the S14 is add a EBC/MBC or an HKS wastegate and adjust it to hold the flapper closed longer..

[shift_SRDETuser]

Both you guys are wrong, Boba is right. The stock boost is 7psi on the S14 sr. The boost pressure did not change from the S13 Sr to the S14 Sr. The only way to increase boost on the S14 is add a EBC/MBC or an HKS wastegate and adjust it to hold the flapper closed longer..

then that would make zilvia, wiki, and nissansilvia wrong as well. Oh yeah that would also make my ASE certified mechanic who has done like 5-6 sr20 swaps from s13 to s14s wrong as well. So, who is wrong and who is right?

[jr_ss]

I'm right and they are wrong... My manual says 7psi... The boost solenoid(that so called "restrictor") is to help in low-end torque and spool...

[redtop91]

Both you guys are wrong, Boba is right.

How am I wrong when I'm talking about the S13 SR?

[shift_SRDETuser]

I'm right and they are wrong... My manual says 7psi... The boost solenoid(that so called "restrictor") is to help in low-end torque and spool...

Have you even read garrett turbos website the diameter of the turbo refers to how quickly it spools -- the s13 has a larger diameter of .86 which is for top end while the s14 has a smaller diameter of .64 which helps low end torque. every site and person I have talked to says that the s14 sr boosts to 1 bar while the s13 boosts to .5 bar. The boost limiter is on s13s and not on s14s. So either you guys are running s13s in your s14 chassis or something is wrong with your engines....

[jr_ss]

How am I wrong when I'm talking about the S13 SR?

I thought that you were reffering to the S14 Sr, because that's what the OP was talking about.

[nzmoman]

When it is removed, boost jumps to 10-11.

I thought when you removed that hose the turbo would boost freely. I remember my first blacktop had a cut hose that I didn't know about until I saw 1 bar on the boost gauge. It was fun as hell but I had to replace the hose to keep my turbo alive.

[jr_ss]

The S14 does not boost 14.7psi stock, nor does it boost 11psi. Are you still running the boost solenoid, previously called "the restrictor"?

[shift_SRDETuser]

I am not running anything yet as my swap is in process but if it only boosts to 7 psi then that is going to suck. About all forums including wiki list the s14 at 10-11 psi on stock boost levels and that you can go up to 14-16 psi safely on stock internals. 1 bar is 14.5 psi but it does not boost to that. I wonder if the sites that claim the 10-11 psi take into affect the removal of the solenoid limiter....

[Tulsa_S-13]

Wow, I'm forced to post in this thread because of the amount of bull**** you people have managed to come up with.

To answer the OPs question, depending on the condition of your T28 you should be able to boost 1 bar without a problem. Most people have found this is a safe limit for the T28 and fuel management.

Refer to Sean's thread on his experience with T28 boost:

zerothread?id=320367

Basically the largest amount of boost the stock tune and fuel system with handle. I had heard 20 psi but am not sure?????

Refer to above answer. At 20psi your T28 is going to be a heat pump.

stock boost is 11 psi...

Wrong!

The stock boost is 7psi on the S14 sr.

Correct!

Despite what some other posters might say suggesting the stock SR's (S13, S14, and S15) boost levels, they came from the factory boosting 7psi.

To clarify, many of the people claiming stock boost levels are near the 10-11psi range are more then likely using the boost pressure solenoid that many engine importers fail to provide. The people running at 10-11 psi have simply discarded the oem vacuum lines that contain the restrictor. This raises boost pressure. I know because before I was running my AVCR I used the boost solenoid with the restrictor and without the restrictor. Without the restrictor boost did increase from 7psi to 10psi.

This is referred to as the "free boost" upgrade.

Read more about this here:

http://www.nissansilvia.com/fo...12212

I thought when you removed that hose the turbo would boost freely. I remember my first blacktop had a cut hose that I didn't know about until I saw 1 bar on the boost gauge. It was fun as hell but I had to replace the hose to keep my turbo alive.

Ryon is referring to removing the restrictor found in the vacuum line for the solenoid. Removing the vacuum line for the wastegate would be a foolish idea and a good way to overboost a motor.

[Tulsa_S-13]

About all forums including wiki list the s14 at 10-11 psi on stock boost levels and that you can go up to 14-16 psi safely on stock internals.

Keep in mind Wiki is user edited. Which is why I never use it for real research.

[shift_SRDETuser]

what is a boost pressure solenoid? My swap came out of a front clip so I have all kinds of little parts with it..

I am just trying to figure out what kind of boost levels I will need to get to running a greddy fmic, bov, and hks filter also fan delete with two radiator spal fans to get to 300 whp on a DD....

[Tulsa_S-13]

Here's a picture I took of it on my setup:



Also, refer to the above nissiansilvia link for more pics.

[shift_SRDETuser]

so the boost solenoid is not the limiter it is in the hose. what if you do not have this boost solenoid?

[redtop91]

On S13 SR's there is a restrictor in a vacuum hose to the boost solenoid that restricts boost to 7 PSI.

[Tulsa_S-13]

so the boost solenoid is not the limiter it is in the hose. what if you do not have this boost solenoid?

The diaphragm in the wastegate actuator operates at 7psi. So without the solenoid you'll run 7psi.

These links might help you better understand the solenoid:

http://www.rx7.org/Robinette/boost_controller.htm http://www.200sx.org/faq_3.html

[shift_SRDETuser]

The diaphragm in the wastegate actuator operates at 7psi. So without the solenoid you'll run 7psi.

These links might help you better understand the solenoid:

http://www.rx7.org/Robinette/boost_controller.htm http://www.200sx.org/faq_3.html

I doubt it came with my swap if it is on the firewall which it looks like where it is. It plugs into the charge intake pipe right? and if not I can just get a greddy spec b boost controller and boost away to 16 lbs high and 10 low -- right?

[Tulsa_S-13]

Wow man, I've seriously given you tons of information that you could have searched for on your own.

The boost solenoid is located on the [US] driver's side. So if you're looking at your front clip it would be on the passenger side strut tower on the mounting plate for the igniter chip.



Here is a picture of it included in the SR vacuum diagram.

[shift_SRDETuser]

kewl I take a look at it tomorrow -- I appreciate it... thanks