20lb safe or not.

I don't think you know what a boost spike is. It's *bad*. You don't want it to happen, period.

I think what you're trying to talk about is call boost taper. The need to gradually drop off boost at high rpm. Something like 13psi@3000 rpm during spool up, 17psi@4500 tapering to 12psi at redline is normal for a turbo car. Something like 13psi@3000, then 22psi@3250, then back to 14.5psi@4000 is a spike and will ruin your motor while getting on the freeway some cool evening.

Without extensive mods and tuning (and a much bigger turbo), no one should be trying to hold 20psi to redline... way too much hot air coming off that small turbo at that sort of flow and boost.

hmmm I call what you call a spike, creep but yeah what im talking about is what you call taper.
 
hmmm I call what you call a spike, creep but yeah what im talking about is what you call taper.
Boost creep is when the wastegate is wide open and boost still builds. Stock STi turbos (vf39's) have a big problem with it when you slap a downpipe on the car.

Boost creep basically looks like an inability to taper, and it'll run the car lean, detonate and take out a rod bearing.
 
Here's what justa4banger and I are talking about with regards to "area under the curve":

dyno_comparo.jpg


On the lest is my WRX tuned with the stock TD03-13 turbo, intake, exhaust, etc. On the right is the same car a bit later on with a slowboy GT30-10 turbo, larger intercooler, and injectors.

Look at the green torque curve and dark blue power curve on the two charts. You'll notice that the GT30 turbo is making 50 whp more peak power and 20 ftlbs more peak torque more than the TD03. But because the TD03's torque curve is like a big flat table, the lower powered setup was actually much faster and more drivable around the autocross course. In order to utilize that GT30-10, I would have had to rev the motor out to 9000 rpm and stayed in 1st gear all the time.

There's a lot more to making a car actually go fast than just turning up the boost and going for a big peak power number. Having that nice table-top torque curve on the low-end is what makes a street car a blast to drive.
 
Sperry i like you. Nothing better than hearing another person talk that has the knowledge and the means to back up thier info.

Look run 20 psi if you like......... or do it right and get a better match turbo and pick up 40-60whp .......... the way it should have been designed......
 
Sperry i like you. Nothing better than hearing another person talk that has the knowledge and the means to back up thier info.

Look run 20 psi if you like......... or do it right and get a better match turbo and pick up 40-60whp .......... the way it should have been designed......
I just figure with all the turbos I've tried, the motors I've blown up, and lessons I've learned along the way, I should be able to pass some of it along to keep others from having to go through the ten of thousands of dollars worth of pain.

The problem is that there's lots of people that refuse to learn except the hard way... but those are also the people that tend to figure out new ways of doing things... it's just important to keep their "pioneering" spirit from infecting others that can't afford to break new ground with a false sense of security or unreasonable reassurances of low risk.
 
see all the misconceptions from people who have never done it ?? i was running 20+psi with nothing more than a CAI and mid pipe for god sake !! did my rods fly out ?? did driver311's motor blow when he ran 24psi ?? nope. look around at all the blown motors on this for and you will see the trends. most of them were actually stock or close to it. all the rest had a standback installed !! coinsedence.....i think not !
people need to grow some balls and try stuff. dont listen to those who will tell you its bad and have no proof. my car gaind power on a dyno and was faster on the track. was that bad ?? my motor has 20k of hard driving and runs like brand new... is that bad ?? and FYI there has only been 1 accurate flow graph for our turbo on the forums and it showed that this turbo can handle 23 psi. the other so called charts you will find are all for the VOLKSWAGEN trim k04, not ours.

Did you run colder plugs while you had the boost up??
 
what i am getting at is mazda isent going to build motors/turbos that are that weak.



Ummmmm i guess you've never heard of the Mazdaspeed Protege...........you know the stock protege motor with a turbo slapped on it? Yea let me tell you how mazda isnt going to put out motors or turbos that are weak haha (jerkit)
 
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I normally run 18-19psi with some 20psi runs. I'm on stock plugs with NO stutter at all. A lot more people are doing it then this forum thinks....

How are you preventing boost cut? With a MAP clamp or an ATP boost cut defender?
 
I normally run 18-19psi with some 20psi runs. I'm on stock plugs with NO stutter at all. A lot more people are doing it then this forum thinks....

And i bet there are alot of people having issues and blowing motors that aren't on this forum........

Just be prepared if the engine pops or something else happens. then when it does............. don't even think going back to the dealer and then bitching about it here on the forum.......

in the mean time enjoy the extra POWA!!!!!!!!!!!!
 
I just figure with all the turbos I've tried, the motors I've blown up, and lessons I've learned along the way, I should be able to pass some of it along to keep others from having to go through the ten of thousands of dollars worth of pain.

The problem is that there's lots of people that refuse to learn except the hard way... but those are also the people that tend to figure out new ways of doing things... it's just important to keep their "pioneering" spirit from infecting others that can't afford to break new ground with a false sense of security or unreasonable reassurances of low risk.

Sage advice ....
 
How many pounds is your vagina would you say? What David is the first member to ever mod a car? Matter fact I don't know why I post on this site. DavidB just delete your post and leave the members on here to themselves.
Wow dude. Way to overreact.

I don't think anyone here is saying "don't mod your car". We're just saying "if you mod your car, make sure you know what you're doing, and be prepared to suffer the consequences if something goes wrong".

There are a ton of people here that are new to tuning turbo cars that are asking very basic questions... like asking "I want to run 20psi" without even really knowing what that means, and there are a lot of people telling them "go ahead, I do it all the time" without mentioning even basic stuff like "I don't even have the same motor as you" (20psi on a MS6 != 20psi on a MS3!!) or "I'm not telling people that I've got a gutted cat, I'm just claiming I'm making boost with an air filter". Basically, there's a crap load of misinformation, and it's a disservice to those that are just getting into this stuff not to point that out.

So don't take it personally, like people are telling you to stop what you're doing. Feel free to take your discussion into the Forced Induction forum and have a technical conversation about it with people that are aware of the risks... but don't get all panties bunched because people like me (who have gone through several motors and learned some s*** the hard way) who are trying to save some n00bs from expensive heartbreak by talking to them straight about the risks of playing with the boost without knowing what you're doing.
 
Wow dude. Way to overreact.

I don't think anyone here is saying "don't mod your car". We're just saying "if you mod your car, make sure you know what you're doing, and be prepared to suffer the consequences if something goes wrong".

There are a ton of people here that are new to tuning turbo cars that are asking very basic questions... like asking "I want to run 20psi" without even really knowing what that means, and there are a lot of people telling them "go ahead, I do it all the time" without mentioning even basic stuff like "I don't even have the same motor as you" (20psi on a MS6 != 20psi on a MS3!!) or "I'm not telling people that I've got a gutted cat, I'm just claiming I'm making boost with an air filter". Basically, there's a crap load of misinformation, and it's a disservice to those that are just getting into this stuff not to point that out.

So don't take it personally, like people are telling you to stop what you're doing. Feel free to take your discussion into the Forced Induction forum and have a technical conversation about it with people that are aware of the risks... but don't get all panties bunched because people like me (who have gone through several motors and learned some s*** the hard way) who are trying to save some n00bs from expensive heartbreak by talking to them straight about the risks of playing with the boost without knowing what you're doing.
If I was mad about what you said I woulda quoted your post and made a comment. Also the dude asked a question, one side is allowed to say 20 pounds is not safe but the other side isn't allowed to say it is? I could care less about what you say I got made when that other dude is trying scold DavidB about when he blows dont go to the dealer. He can **** off just cause he's scared to do anything with his car doesn't mean he should act like that.
 
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