Boosting T-25

[nattyice0677]

What is the most boost you can run on the stock T-25? and what kinda hp numbers would we be looking at?

 

[blackGSX2g]

I really wouldn't push it past 15psi. After that its pretty much blowing hot air into your motor. HP figures depend on your current mods, but if you have IC pipes, upgraded BOV, an exhaust I wouldn't think much more than a 20hp gain over stock. I could be wrong, but when I ran 15psi, I didn't notice much of a difference at all over stock boost, but that could be cause my stock boost level was 14 psi. Every car is a bit different.

 

[GOT 2RBO]

i just looked at your vehicle profile and you're running bone stock. you can't do much with your plastic BOV coz it leaks boost @12psi (which is stock boost). after you change that BOV, you can up your boost up to 16psi max coz you're wastegate spring would only hold 16psi of boost. since you have an internal wastegate, swap the turbo to a bigger one would be next. after you swap turbo, you still can't boost past 16psi coz of stock fuel and heat soak factor on stock smic.

replace your BOV, then after that, replace your intercooler piping. those rubber/plastic upper and lower intercooler piping expands under boost and that expansion is wasted boost.

good luck

 

[blackGSX2g]

you can up your boost up to 16psi max coz you're wastegate spring would only hold 16psi of boost. since you have an internal wastegate, swap the turbo to a bigger one would be next.

If you have a MBC, you can boost to your hearts content...What is a wastegate spring? Its a vaccuum actuator, and its set from the factory and cannot be changed. A MBC just bleeds off pressure so the wastegate sees less boost, therefore opening later.

 

[GOT 2RBO]

If you have a MBC, you can boost to your hearts content...What is a wastegate spring? Its a vaccuum actuator, and its set from the factory and cannot be changed. A MBC just bleeds off pressure so the wastegate sees less boost, therefore opening later.

i do have an MBC and no you can't boost up past 16psi. you're right though, there's a vacuum actuator. but what do you think is pushing back on the boost going there? for it to get "actuated" boost has to be pushing on it but it has to have a force (spring) to push back otherwise it'd stay open all the time. when that threshold is met (16psi), the actuator is pushed open therefore dumping good boost into the exhaust system wasting it, hence the name... wastegate!

 

[MattnGsx]

i do have an MBC and no you can't boost up past 16psi. you're right though, there's a vacuum actuator. but what do you think is pushing back on the boost going there? for it to get "actuated" boost has to be pushing on it but it has to have a force (spring) to push back otherwise it'd stay open all the time. when that threshold is met (16psi), the actuator is pushed open therefore dumping good boost into the exhaust system wasting it, hence the name... wastegate!

Then you most have some kind of boost leak, or a partialy stuck open wastegate. When I replaced my up icpipe, and bov I boosted 20psi, on that poor t-25 all day, then I blew it.

Also I know of people who have just replaced the bov, and can run 18-20psi.

Also the spring rate is set up for about 10 psi on the actuator not 16.

 

[GOT 2RBO]

you know what? get a moderator on this subject! if i'm wrong then i appologize, in that case i was mis-led by a mechanic's explanation. think about it though, a 14B is not much bigger than a t2small yet the boost capability of the 14B is greater due to the internal wastegate. it's able to hold more boost without bleeding it to the exhaust...

 

[GOT 2RBO]

Then you most have some kind of boost leak, or a partialy stuck open wastegate. When I replaced my up icpipe, and bov I boosted 20psi, on that poor t-25 all day, then I blew it.

Also I know of people who have just replaced the bov, and can run 18-20psi.

Also the spring rate is set up for about 10 psi on the actuator not 16.

if the spring rate is set at 10psi, how do you get 12psi stock? boost would get dumped at the wastegate @ 10psi if that was the case. wastegate threshold is greater than the stock plastic piece BOV which bleeds at 12psi. that means wastegate is holding up more than the bov, then when the bov is replaced with a better one (1G or aftermarket), the wastegate is now less capable (which is @ 16psi).

 

[MattnGsx]

if the spring rate is set at 10psi, how do you get 12psi stock?

Stock BCS

I would comment about the rest, but I realy couldn't understand what you where tryn to say.

 

[noz]

do a search.
i think it was larryd who did a dyno with different boost settings
and it still made power pass 15psi.

 

[blackGSX2g]

Stock BCS

I would comment about the rest, but I realy couldn't understand what you where tryn to say.

Yea, DSMs come with an electronic boost controller stock...disconnect all the vaccuum lines to the wastegate and just hook up a hose from from a pressure source to figure out what your stock wastegate is set exactly at.

you know what? get a moderator on this subject! if i'm wrong then i appologize, in that case i was mis-led by a mechanic's explanation. think about it though, a 14B is not much bigger than a t2small yet the boost capability of the 14B is greater due to the internal wastegate. it's able to hold more boost without bleeding it to the exhaust...

Both the 14b and the t-25 are internally gated, as is my Evo 16g. The reason there are performance differences between them lie within the trim and A/R of the turbo. Hence why my evo at 15psi is alot better than my t-25 at 15psi.

If you don't believe me on the wategate thing, pull off the vaccuum line to your wastegate on your turbo and floor it...see what kind of boost it builds.

 

[GOT 2RBO]

Stock BCS

I would comment about the rest, but I realy couldn't understand what you where tryn to say.

hooked on phonics didn't work for you? you would comment but you couldn't understand what i WHERE TRYN to say? WHERE i am is New York, i don't know who TRYN is.

 

[Ntrain2k]

hooked on phonics didn't work for you? you would comment but you couldn't understand what i WHERE TRYN to say? WHERE i am is New York, i don't know who TRYN is.

No need to start acting childish.

It's a technical forum, not the special olympics...

 

[Defiant]

The wastegate won't get opened by exhaust pressure. The BOV valve will be blown open by intake pressure (boost). The wastegate must be pushed open by the boost level: this is why running without a boost controller will make a DSM go bang. Uncontrolled, a T-25 will make more than 25psi, but nothing will live through it (including the turbo), or not live for very long.

Before the misinformation becomes more convoluted here, I'm closing this thread.

 

[me612]

i do have an MBC and no you can't boost up past 16psi. you're right though, there's a vacuum actuator. but what do you think is pushing back on the boost going there? for it to get "actuated" boost has to be pushing on it but it has to have a force (spring) to push back otherwise it'd stay open all the time. when that threshold is met (16psi), the actuator is pushed open therefore dumping good boost into the exhaust system wasting it, hence the name... wastegate!

OK before you close this, maybe the info needs to be straightened out, because it's obvious there's lots of confusion here.

First lets get it straight how a MBC works and controlls the wastegate. Lets say you have a 10psi wastegate actuator. Well there are vacuum lines going to the actuator. Once it 10psi is felt thru the lines AT the wastegate, the wastegate will open. Now put a MBC in the path, before the WG actuator. It consists of a ball on top of a spring. The ball is blocking the air from coming through, so the wastegate isn't seeing any pressure. How stiff that spring is will depend on how tight you tighten the MBC. Make it real tight, and it may take 25psi of pressure to push that ball down and let the air past. So that is how you boost past 10psi, even though you have a 10psi actuator.

Now about what wastegates do. Once it is actuated and it opens, it does not "Dump boost into the exhaust". It opens, and allows some of the exhaust to bypass the turbos exhaust wheel. So instead of more exhaust just going thru and spinning that wheel faster until it just can't go any faster, it will bypass some of the exhaust through the wastegate instead of all of it going through the turbo. So that way you stay at that boost level you selected the wastegate to actuate at. Make sense?

So if you decide to run NO boost controller, just a straight vacuum line to the wastegate, it will open as soon as you reach whatever psi it's rated to actuate. But if you run no boost controller, just leaving the wastegate unattached from the vacuum system, well then it's gonig to stay closed, and that turbo is going to boost as fast as the exhaust can push it, which could result in a very bad ending.

 

[boostyGST]

ok ..... so what happens when you upgrade to a front mount intercooler, can you boost over 15psi safely with the T25. I mean by putting on a larger and more effecient intercooler are you not going be able to cool the air and more intense of pressure?

thks, tyler

 

[midnght]

Why is this always argued?


Spelling is not a criteria we sign up for [Check again. Yes, it is.] so stop acting like you are from the 2004 spelling bee. :thumbdown

This is a technical forum that runs off of experience not hear say.


I DID run 19psi daily on my T-25. Granted I had a GReddy-S and the pipe kit. But it ran that way and ran good for atleast 6 months. Then I sold it to a guy running a shop. He put it on his shop civic for tuning on boost. The turbo boosted good, not leaking or any stupid shit like that.



Do not write GUESSES. It is rule number 3 above the response box.

 

[ozzeran]

I agree to the spelling criteria. On a MBC with i/c hard pipes my T-25 boosted to 24psi and then bam fuel cut off. I only did that 2 times just ####ing around. This was with the mbc almost turned all the way to full boost. Granted I was stupid, but oh well. That T-25 will boost fine. If I had fuel pump/rewire on it, I would run 18psi daily probably with no problem. But i'm still waiting on more parts.

Why is this always argued?


Spelling is not a criteria we sign up for so stop acting like you are from the 2004 spelling bee. :thumbdown

This is a technical forum that runs off of experience not hear say.


I DID run 19psi daily on my T-25. Granted I had a GReddy-S and the pipe kit. But it ran that way and ran good for atleast 6 months. Then I sold it to a guy running a shop. He put it on his shop civic for tuning on boost. The turbo boosted good, not leaking or any stupid shit like that.



Do not write GUESSES. It is rule number 3 above the response box.