sr20 myth busters

[dr1ft32]

ok, there is alot of myths out there and i think that this would be a great thread for the myths to be busted.

ill start out with my question/myth is the sr20det stock boost really 7lbs or is it 11lbs from factory. as stated in the sr20det faq

heres a few basics...

stock boost IS 11lb's
boost w/o solenoid 7lb.
do not boost stock s13 t25 over 14lb. it's useless.
12's are possible on stock turbo
__________________

then it goes on to

The 11lbs without a solenoid thing for who wanted it explained. There is a solinoid that actuates the wastegate, but to my understanding doesn't come with the SR motorsets, because it's mounted elsewhere in the engine bay. So you'd have to get one, use a boost controller, or run the vaccum hose from the nipple on the intercooler directly to the wastegate, bypassing the valve function. Without this solenoid it should run 11lbs.

then it goes on to

ok...my official correction of my previous statement. After checking the lines more closely and doing more research...hooking the line from the wastegate to tb will get you 7lb. hooking the wastegate to the solenoid then to tb does what has been said....it actually restricts the airflow and brings you to 11lb....no vac on wastegate does indeed give infinite boost (not good)....thank you guys for questioning me and helping me learn and not treating me like a dumbass...you guys are awesome....yet again proves....this is a great board! Keep up the good work!

so my question is to clarify this. is it stock from factory in japan 7lbs or 11lbs.

this might be a bad thread and i have searched with that being said. flame on

[SoguRacing]

it has been answered before. It is 7.5 pounds of boost. .5 bar. 1 bar = 14.7psi

[mulinmoua]

so whats up with this boost solenoid thingy then. is it just a jimmy rig for a cheep boost controller or what??

[SoSideways]

so whats up with this boost solenoid thingy then. is it just a jimmy rig for a cheep boost controller or what??

It's a stock part.

Unless people are calling stock parts "jammy rigs" now...

[Addicted2Kouki]

I've seen 20 psi on a stock sr w/ a t25.
Ask norm.

IIRC....It was faster than his HKS tuned gt2871r at i think it was 15psi.



of course. it didnt last.
but the surprising thing is the t25 didnt blow, the headgasket did.

[SoSideways]

I've seen 20 psi on a stock sr w/ a t25.
Ask norm.

IIRC....It was faster than his HKS tuned gt2871r at i think it was 15psi.



of course. it didnt last.
but the surprising thing is the t25 didnt blow, the headgasket did.

Just cause you've seen 20psi on the stock T25 doesn't mean that's the stock pressure that it pushes out.

Member Unisa Jecs was trying to find out how much boost the SRs had from the factory, and there was already a thread on it.

I think it was a big toss up still, since there were people confirming both 11psi and 7psi.

In any case, boosting more than 10 or 11psi on the T25 won't really do much. You might see an extra like 15 ft-lbs of TQ in the mid range if you cranked it up to 14psi, but it'll still taper back off to like 10.

[dr1ft32]

[QUOTE=SoSideways;2329585]

Member Unisa Jecs was trying to find out how much boost the SRs had from the factory, and there was already a thread on it.

I think it was a big toss up still, since there were people confirming both 11psi and 7psi.

QUOTE]

exactly, so is it 7 or 11. i believe that it is 7 but then again there are still people saying that it is 11lbs.

[dr1ft32]

It's a stock part.

Unless people are calling stock parts "jammy rigs" now...

i know its a stock part, so does that mean that it is 11 lbs stock then or 7lbs ???

[SoSideways]

I myself am a firm believer that it is supposed to be at 11psi stock.

But I will never know because I don't plan on buying the stock solenoid to test it out myself.

[bardabe]

it's like Z32's the solenoid is there for safey. stock boost is 11lbs. when it sees knock it brings it down to 7psi. want to question me?

[dr1ft32]

so for instance, a red top is 205hp at 11psi then??? and if you dont have the solenoid then the engine is automatically going to be at 11psi or 7psi. and just to clear things up im not doughting anyone, just want to make sure what it is

[Addicted2Kouki]

Just cause you've seen 20psi on the stock T25 doesn't mean that's the stock pressure that it pushes out.

Member Unisa Jecs was trying to find out how much boost the SRs had from the factory, and there was already a thread on it.

I think it was a big toss up still, since there were people confirming both 11psi and 7psi.

In any case, boosting more than 10 or 11psi on the T25 won't really do much. You might see an extra like 15 ft-lbs of TQ in the mid range if you cranked it up to 14psi, but it'll still taper back off to like 10.

I was only referring to when he said not to boost over 14 psi.

I know all about that thread. I'm not arguing what the stock psi is.
It has already been established that its 11psi with the solenoid and 7 without it.

If you think boosting more than 10 or 11 psi wont really do much.. think again.
You are just repeating everything you have read.
Don't speak unless you have experience.
You will see and feel a difference.
The 20psi was by mistake from a home depot DIY boost bleeder somewhat like the stock solenoid.
Only it wasnt very accurate and would open and close on its own, sometimes seeing anywhere from 10-20 psi.

Would this be safe or smart? not so much for the engine or turbo.
Will it be faster... Yes.

[Addicted2Kouki]

so for instance, a red top is 205hp at 11psi then??? and if you dont have the solenoid then the engine is automatically going to be at 11psi or 7psi. and just to clear things up im not doughting anyone, just want to make sure what it is

sounds about right.

You gotta look at it like this...

The wastegate fully opens whenever it sees 7 psi.
The solenoid acts as a bleeder and only allows it to see X psi to a certain point.

The wastegate still thinks its opening at 7 psi because its just a spring.
When in actuality it could really be seeing 11 psi to the actual turbo.

[dr1ft32]

so all the people without that boost soleniod are losing out on power then, wow. thats interesting. from the post in the sr20 faq, it stats majority of the poeple dont have it cause majority people buy motorsets instead of clips, interesting to know. thanks alot

[SoSideways]

I was only referring to when he said not to boost over 14 psi.

I know all about that thread. I'm not arguing what the stock psi is.
It has already been established that its 11psi with the solenoid and 7 without it.

If you think boosting more than 10 or 11 psi wont really do much.. think again.
You are just repeating everything you have read.
Don't speak unless you have experience.
You will see and feel a difference.
The 20psi was by mistake from a home depot DIY boost bleeder somewhat like the stock solenoid.
Only it wasnt very accurate and would open and close on its own, sometimes seeing anywhere from 10-20 psi.

Would this be safe or smart? not so much for the engine or turbo.
Will it be faster... Yes.

Oh I've spiked up to 20psi before also.

I've also had to replace my head gasket a few weeks late because the 20psi spikes gave my headgasket some slow leaks.

Was it faster? Maybe. It was only 1st gear and I only stayed in it until I saw 20psi, then I lifted.

Did it blow my headgasket? Probably.

All else being stock, you really think you can sit there and boost 20psi all day long? No.

14psi is pretty much max, since you'll run out of injectors and MAF around that point, and the turbo is really just blowing hot air past 12psi anyway, so why push 14, or even 20psi through it?

Unless you're from the DSM crowd, practicing DSM standard procedure by running any turbo up to 20psi as low boost, and "letting the intercooler do its job by cooling all that hot air that the turbo is blowing past its efficiency point", then sure, go ahead. You'll probably have to rebuild the engine/turbo like every month like the DSM crowd too then.

I'm not attacking you man, I'm just saying, running that dinky T25 more than 12psi is pretty much silly. Yeah it'll spike to whatever before coming back down to 10psi by redline, but really, why are you trying to push the engine/turbo that much?

[IStop4NoMan]

Ive used both methods, with and without the solenoid. I was boosting 11psi with about a 13psi spike with the solenoid. i removed the solenoid because i wanted to go with a manual boost controller. so for the time that i only had a vaccum line going to the turbo, i was sitting at 7psi. the car is wayyyy more fun at 11psi. just that extra 4 pounds makes a huge difference to me.

[SoSideways]

Ive used both methods, with and without the solenoid. I was boosting 11psi with about a 13psi spike with the solenoid. i removed the solenoid because i wanted to go with a manual boost controller. so for the time that i only had a vaccum line going to the turbo, i was sitting at 7psi. the car is wayyyy more fun at 11psi. just that extra 4 pounds makes a huge difference to me.

It's true.

When the car hits 7psi, it feels like something's about to happen, but it doesn't.

Kinda like when you're doing a chic from the back, and it feels oh so good, then you're like "oh yeah I'm near" and she just goes "oh that's great, I gotta go, see ya" and gets off your D and puts her clothes on and leaves.

That's what 7psi feels like.

10+ psi is actually more like, you actually get to the point of climax, and the chic just turns around, gets on her knees, and takes the protein shake all frontal, on her face, etc.

Knowing is half the battle, and now you know!!

[TheRonTom31]

AHAHAHAAA.

Best comversation ever

[s14unimog]

Guys, the discussion about the solenoid is been drug around on here for ever. the ABSOLUTE TRUTH of the mater is that stock boost, as said by Nissan, is 11psi. Garrett, the manufacture of the turbo, places a 7psi spring in that turbo to allow a default pressure rating. If you don't believe me or any other member on this board that supports this idea then you need to do more research on turbo cars. It is very UNCOMMON to see an OEM turbo application that does not run a boost solenoid. A great example is the Evolution. I've personally installed a EBC on one and found that you start with 10psi (w/removed solenoid) and increase from there to pass Mitsubishi's pressure of 19PSI (stock boost).


STOCK BOOST IS 11PSI, END OF DISCUSSION!


You gotta look at it like this...
The wastegate fully opens whenever it sees 7 psi.
The solenoid acts as a bleeder and only allows it to see X psi to a certain point.
The wastegate still thinks its opening at 7 psi because its just a spring.
When in actuality it could really be seeing 11 psi to the actual turbo.

You sir are correct!


If someone would be so kind to post Garrett's compressor map for the stock T25. I can tell you what that turbo can and can't do as per Garrett's specifications. Most people on here can't even read a compressor map but don't hesitate to tell you what a turbo's max capabilities are...

If you are running 7psi, b/c you think its "stock" then your car must be slow and I feel sorry for you doing it.

[Chrischeezer]

there's a roomer that a STOCK sr20det bottom end held 995hp build , with a t88 and a 150 shot.
anyone ever herd of this??

[Addicted2Kouki]

That actually makes me wonder.

If the T25 HKS Actuator bumps up the Wastegate to 10psi, and the Stock Boost Solenoid bleeds off what the wastegate is seeing, effectively giving it 4 more psi...

How much psi would the Stock SR Solenoid + an HKS Actuator push?
about... 14 psi, right?


EDIT:
Or do they even work in conjunction with each other?

[s14unimog]

^ they don't you can only run one or the other.

[gippy87]

I dont know for sure what stock is but i belive its deffinitly higher then 7psi. I imagine it is a similar setup to the 300zxtt where the stock wastegates are set for 7psi but it uses a solenoid to restrict air to the wastegates allowing it to hit 11psi and if the motor is knocking it goes into saftey mode and runs with the solenoid open so that it only hits the 7psi and you dont blow the motor. I may have made that alot more confusing that it should have been but if you knwo how a wastegate works then you should understand

[Mister.E]

my stock SR redtop, in my 180sx, that is in japan, and has never been swapped runs a little over .7bar at full boost, stock boost on an SR is in fact 11lbs. im not sure what other information you guys need to be convinced of this...so as previously said, END OF DISCUSSION

[d-magic]

the boost solenoid is there to control boost spike. that's it's purpose. when i removed mine from my 180sx, i would get boost spike when i ran it at 1bar...it would jump to 1.1bar, so i brought it down to 0.9 bar.

[jonathan12uiz]

ok, there is alot of myths out there and i think that this would be a great thread for the myths to be busted.

ill start out with my question/myth is the sr20det stock boost really 7lbs or is it 11lbs from factory. as stated in the sr20det faq

heres a few basics...

stock boost IS 11lb's
boost w/o solenoid 7lb.
do not boost stock s13 t25 over 14lb. it's useless.
12's are possible on stock turbo
__________________

then it goes on to

The 11lbs without a solenoid thing for who wanted it explained. There is a solinoid that actuates the wastegate, but to my understanding doesn't come with the SR motorsets, because it's mounted elsewhere in the engine bay. So you'd have to get one, use a boost controller, or run the vaccum hose from the nipple on the intercooler directly to the wastegate, bypassing the valve function. Without this solenoid it should run 11lbs.

then it goes on to

ok...my official correction of my previous statement. After checking the lines more closely and doing more research...hooking the line from the wastegate to tb will get you 7lb. hooking the wastegate to the solenoid then to tb does what has been said....it actually restricts the airflow and brings you to 11lb....no vac on wastegate does indeed give infinite boost (not good)....thank you guys for questioning me and helping me learn and not treating me like a dumbass...you guys are awesome....yet again proves....this is a great board! Keep up the good work!

so my question is to clarify this. is it stock from factory in japan 7lbs or 11lbs.

this might be a bad thread and i have searched with that being said. flame on

From what I have read. STOCK boost is 11psi because of the boost pressure solenoid. Now most people who swap their KA for an SR don't have the boost solenoids. I've also seen those same people route their vacuum lines wrong because of that.
If you look at the OEM routing of vacuum lines you can see the boost solenoid is in the mix. Now because MOST of us get motorsets rather than clips you HAVE to set it up like this to be safe:

I don't know if you fixed this yet, but here is how you NEED to do this.

There are 3 nipples on the throttle body. 2 on the top and 1 on the bottom.

- Cap off the bottom one, you don't need it.
- The top left (which is the smaller diameter one) goes to the fuel pressure regulator. This is also the same line that you can tee into for a boost/vac gauge.
- The top right (which is the LARGER diameter one) is connected directly to your BOV.

You are probably wondering why I didn't tell you to connect your wastegate to any of those lines. The reason is because YOU DON'T TEE YOUR WASTEGATE TO YOUR BOV!

Go to home depot or lowes and buy a threaded brass nipple with the same size as your vacuum lines.
Take your hotpipe off and drill a hole matching the diameter of the threaded end of the brass nipple.
TAP the hole using a pipe thread size tap. (you can get these at auto part stores)
Wrap the threaded end of the brass nipple with teflon tape
and last... thread it into your hotpipe and run a vac line as short as possible to your wastegate and BAM you are done.

Note. the bottom vac nipple on the throttle body could go to the charcoal canister, BUT you don't need that useless thing. just take it out like i did and save some weight. LOL!

now i've seen some post about wastegates reading vac. That is incorrect. The wastegate actuates based on pressure (PSI). that is why you see how I told you to route the wastegate off the hotpipe.

Now to get back to the stock 11psi boost range, you have to Tee into the wastegate line I told you about and run a manual or electronic boost controller.

[johngriff]

usually its in there, attached to the ignitor, on the bracket, being thrown away by 16 year olds.

And bitching about 4psi on a stock turbo? Jokers. You would think by 2008 no one would even run a stock turbo any more.

[aziankingz]

dude, how about searching. No one reply back. He needs to learn.

.. .

[aNskY]

there's a roomer that a STOCK sr20det bottom end held 995hp build , with a t88 and a 150 shot.
anyone ever herd of this??



:rofl: :rofl:


what is your definition of "held"? one dyno pull?