Whats stock boost for S13 S14 SR20DET

[UNISA JECS]

Sounds like a very simply question but one that isn;t very easy to find a deffinate answer to.

What I do know:
S13 SR20DET
Wastegate actuator has a 7lbs spring so it is either 7psi or higher, now before someone jumps in and says you answered your own question not so fast.

The W10/W11 Avenir AWD SR20DET commonly swapped into the FWD B13/B14/P10/P11 chassis also has a stock wastegate actuator with a 7lbs spring inside, but is boost controlled from the factory to .65bar (9.4psi) IIRC.


What I dont know:
S14 SR20DET
I dunno nothing about that not even what the stock wastegate actuator is rated at with no boost control if any.

[s15specR]

got the same question...bump

[burnsauto]

Originally Posted by UNISA JECS

Sounds like a very simply question but one that isn;t very easy to find a deffinate answer to.

What I do know:
S13 SR20DET
Wastegate actuator has a 7lbs spring so it is either 7psi or higher, now before someone jumps in and says you answered your own question not so fast.

The W10/W11 Avenir AWD SR20DET commonly swapped into the FWD B13/B14/P10/P11 chassis also has a stock wastegate actuator with a 7lbs spring inside, but is boost controlled from the factory to .65bar (9.2psi) IIRC.


What I dont know:
S14 SR20DET
I dunno nothing about that not even what the stock wastegate actuator is rated at with no boost control if any.

stock from the factory is around 10-11 (i cant remember the exact number) with an inline bleed off solenoid

stock for most of the swaps in the US....7lbs.

[UNISA JECS]

Heres a picture for anyone that might be wondering what it looks like that didn;t get a full clip:

[Petoria]

With my notch top win I installed my boost gauge It read between 6.7 and 7 psi at stock.

[UNISA JECS]

Originally Posted by Petoria

With my notch top win I installed my boost gauge It read between 6.7 and 7 psi at stock.

I guess notch top is S14? ok so if it is that pretty much tells me that the stockwastegate has a 7lbs spring inside it, now if we can find out the factory boost pressure.

[slidingsky]

S13 red and black top & S14 SRs are rated at 7psi
The Avenir (silvertop/no paint VC) is rated at 7psi as well
The GTiR is rated at 10psi

[FusionR240sx]

yea my red top is @ 7psi

[UNISA JECS]

Originally Posted by slidingsky

S13 red and black top & S14 SRs are rated at 7psi
The Avenir (silvertop/no paint VC) is rated at 7psi as well
The GTiR is rated at 10psi

If you are speaking in terms of stock wastegate rating we know that (except for the GTi-R I didn't know that)

But we wanna know what the stock boost is from the factory, if you say its 7psi that doesn;t make much sense because what would be the purpose of the factory boost solenoid

For example:

U12 Bluebird rated at ~207ps journal T25g

U13 Bluebird rated at

W10 Avenir rated at 230ps journal T25g

W11 Avenir rated at 230ps ball bearing 25g

RNN14 GTi-R rated at 230ps journal T28

I imagine none of these boost 7psi from the factory, what would be the purpose of a boost solenoid then.?

[SoSideways]

Originally Posted by slidingsky

S13 red and black top & S14 SRs are rated at 7psi
The Avenir (silvertop/no paint VC) is rated at 7psi as well
The GTiR is rated at 10psi

Originally Posted by FusionR240sx

yea my red top is @ 7psi

Are those numbers with or without the factory boost solenoid?

Pretty sure this thread was created to dispel some of the myths or questions surrounding the inconsistent answers that are always giving about the stock boost pressure on the S13/S14/S15 motors.

Most people in the US claim stock boost pressure is 7psi on the S13, because a lot of them don't have the stock boost solenoid on there, or their's aren't working, thus so far, everything "assumes" that it's 7psi stock.

I think Unisa Jecs is trying to PROOF it once and for all, so we can all put it on the records and say "yes, stock is ___psi".

[UNISA JECS]

Maybe I wasn;t clear enough in my first post, my bad.....I just dont wanan see a bunch of people replying that they boost 7psi, we know this already, that just means you dont have the stock boost control solenoid in your car working.

Please read the first post again and then look at whats highlighted in RED about the Avenir.

[SoSideways]

I don't have time right now to look through the S14 SR20DET FSM that's commonly found on the internet as a PDF file, but I'm sure it mentioned the boost solenoid in there.

I just don't remember if it mentioned the default pressure of boost it's supposed to generate if it's working properly.

[UNISA JECS]

Originally Posted by SoSideways

I don't have time right now to look through the S14 SR20DET FSM that's commonly found on the internet as a PDF file, but I'm sure it mentioned the boost solenoid in there.

I just don't remember if it mentioned the default pressure of boost it's supposed to generate if it's working properly.

I have the S14 SR20DET FSM on PDF as well with no specs given as to the stock boost pressure, howver I will look again just to make sure.

Same thing goes for the RNN14 GTi-R I have a FSM for that to with the same, no mention of the stock boost pressure, I will look again to make sure as well.

[SHIFT_*grind*]

Originally Posted by burnsauto

stock from the factory is around 10-11

Yep. I'm almost certain it's 11lbs for the S13 SR. I'm not quite as sure for the S14.

[UNISA JECS]

You know what im going to ask Matt from Nistune since he is in Australia and AFAIR they sell factory Nissan SR20DET atleast S14 im not sure if they sold S13 out there.

[SoSideways]

Well, I'm pretty sure there were/are members on this board that lived/lives in Japan, so if they could chime in about this subject, that'd be cool.

[slidingsky]

The point of the Nissan boost solenoid is to switch from the low boost and high boost settings. Low boost is 4psi high boost is 7psi.

I didn't know that about the Avenirs.... we really don't get those motors to often so I haven't put that much research into them.

[UNISA JECS]

Originally Posted by slidingsky

The point of the Nissan boost solenoid is to switch from the low boost and high boost settings. Low boost is 4psi high boost is 7psi.

Thats impossible, the wastegate has a 7lbs spring, therefore you cannot control boost but at anything but 7psi or greater.

By default if the boost soleniod failed your boost would drop to 7psi via the rating of the stock actuator.

I know that the U12 U13 W10 S13 all have 7lbs wastegate srpings +/- .5lbs

*AWD SR20DET engines are my background knowledge of the SR20DET, I just have never knew for sure the stock boost of any but the W10 Avenir.

[SHIFT_*grind*]

4 pounds is way too low. Boost without a solenoid is 7 pounds; the solenoid can *only* increase boost, not decrease it.

Gah, beaten to the punch.

[s13silvia88]

i have the stock boost ssolenoid in my sr20det its a red top , and it boost exactly at .5bar there for 7 psi

[UNISA JECS]

Originally Posted by s13silvia88

i have the stock boost ssolenoid in my sr20det its a red top , and it boost exactly at .5bar there for 7 psi

Know if you can prove that it is working 100% and hooked up correctly is another story, not doubting you that its hooked up and all, but for it to only be boosting 7psi makes no sense of having a boost control solenoid at all.

You could disconnect your solenoid and I can guarntee you yoru boost will not drop below 7psi +/- .5psi (for wear and tear of the wastegate)

[slidingsky]

What sense does it make to boost to X Psi if you have a wastegate that is rated for 7 Psi? The real question would be to get something around a 15 Psi spring and then see what happens with a working boost solenoid in place. Assuming that it really is 11 Psi like suggested (not doubting it btw).

[SHIFT_*grind*]

Originally Posted by slidingsky

What sense does it make to boost to X Psi if you have a wastegate that is rated for 7 Psi? The real question would be to get something around a 15 Psi spring and then see what happens with a working boost solenoid in place. Assuming that it really is 11 Psi like suggested (not doubting it btw).

It makes perfect sense, because if you have a 15 psi wastegate spring, you cannot boost less than 15 psi.

All a boost controller or boost solenoid does is create a controlled leak so that the wastegate thinks the manifold is seeing less pressure than it actually is.

Stock wastegate actuator is 7 pounds. The factory solenoid creates a controlled leak between the manifold and the actuator so that when the manifold sees 10-11 pounds (pretty certain it's 11), the actuator sees 7 and opens up.

[UNISA JECS]

Originally Posted by SHIFT_*grind*

It makes perfect sense, because if you have a 15 psi wastegate spring, you cannot boost less than 15 psi.

All a boost controller or boost solenoid does is create a controlled leak so that the wastegate thinks the manifold is seeing less pressure than it actually is.

Stock wastegate actuator is 7 pounds. The factory solenoid creates a controlled leak between the manifold and the actuator so that when the manifold sees 10-11 pounds (pretty certain it's 11), the actuator sees 7 and opens up.

Also this controlled leak is not lost to atmosphere it is simply re-routed back to the intake trake between turbo and MAF like it should be since it has been accounted for already by the MAF sensor.

[UNISA JECS]

When you think about all this:

KA24DET @ 7psi has an effective compression ratio of 14.0:1

SR20DET @ 7psi has an effective compression ratio of ~12.5:1

SR20DET @ 9.7psi has an effective compression ratio of 14.0:1

This shows one example why it takes more boost on a SR to make the same horse as the KA all things equal.

Factory boost pressure has to be similar to the Avenir SR20DET from the factory.

[s13Eper]

Stock redtop swap here. ~11psi (autometer) with stock boost solenoid.

[UNISA JECS]

Originally Posted by s13Eper

Stock redtop swap here. ~11psi (autometer) with stock boost solenoid.

Ok thats good info, I know most autometer gauges are off about 1psi though, I owned one and about 4 on my friends owned then as well and there were all usually ~1psi high I compared all there gauges this is years ago against my Apexi gauges and the differences where clear to see.

To add to this just called my friend that I swaped a W10 Avenir SR20DET into his B13 Sentra SE-R years ago and I just remember he installed a RNN14 GTi-R T28 journal bearing and he told me the actuator pressure is ~9psi but thats only confirming the wastegate rating.

[SoSideways]

Originally Posted by s13Eper

Stock redtop swap here. ~11psi (autometer) with stock boost solenoid.

DING DING DING!!

I think we have a weiner!

[Sileighty_85]

Im sure that the S14 Boost level is no Higher than the Red Top Since the S14 still runs 370cc Injectors

I have a video @ home of a RHD BONE STOCK 180SX with a close up on the boost gauge when I was test driving it, I will find it and upload it when I get home... If interested.

If I remember correct I dont think I ever saw it go above .7 Bar

[UNISA JECS]

Originally Posted by Sileighty_85

Im sure that the S14 Boost level is no Higher than the Red Top Since the S14 still runs 370cc Injectors

I have a video @ home of a RHD BONE STOCK 180SX with a close up on the boost gauge when I was test driving it, I will find it and upload it when I get home... If interested.

If I remember correct I dont think I ever saw it go above .7 Bar

Hp rating is higher on S14 isnt it plus has a T28 correct? If so that makes perfect sense.

Try and get the video uploaded if you can that'll be cool.