I have always wondered, why do people talk about boost pressures so much. For instance, a common thread used to be "how much boost can I run on my stock block?" Golden Eagle is another culprit, stating their blocks can handle 60psi of boost pressure. Today a not so knowledgable chap asked me how much boost I was running on my 240, not having any idea what size turbo I was running.

Boost is only a measuring stick for pressure in the intake manifold. After that, it's purely up to how much air + how much fuel + how much spark + how much compression = horsepower. Yes, boost pressure can regulate how much air the motor is injesting, but 60psi through a T100 is not the same as 60psi through a T25.

Companies and people need to stop using incorrect adjectives to describe things in the automotive world. True, it might be easier to just say how much boost, but in reality, cylinder pressures (and thus power) are what dictates a mechanical failure under normal conditions with regards to block building.

 

Amen!

 

true

 

not everyone is as knowledgeable as you
for those of us who do understand what your talking about
we know how you feel

 

Agreed.

However, is there a possibility that the block is rated as such, because the things that break them are more related to cylinder pressures than power output?

I started writing an article about this months ago, to add to my collection (I already have done some, a few are posted on here) but I haven't finished it yet...

Maybe I should get off my ***.

I agree though. AIRFLOW, either in mass per time interval, mass per rev, or corrected volume per time interval, is what REALLY matters.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">Agreed.

However, is there a possibility that the block is rated as such, because the things that break them are more related to cylinder pressures than power output?</TD></TR></TABLE>

could be true, if not for the fact that cylinder pressures = power output. Lower pressure, lower output, higher pressures, higher output.

 

John your right, but what ive learned in the game is that everything is RELATIVE to something else.

 

You got to sell parts for cars somehow.

I know what you mean. I walk into motorsport shops, check out shows, even get asked by the local up-and-coming future rice rocketer what they should use in their car.

We all started someplace. I remember when I thought that adding an intake made my car faster than a Porsche Carrera...those were the days. ANYWAYS, saying something like "I'm pushin' 16 psi of boost" works good with the street crowd. Try saying that to someone, perhaps like yourself, at an autoX or professional race and those individuals will politely smile, shrug, turn and leave.

Put it this way, you know, they don't. Saves you $500 when you opt to NOT buy that electric turbo with programmable BOV sound effect @ 2 psi of boost.

 

i only care how fast my car is.

 

John, I've asked this question a number of times over the past 5 years or so. The culprits are marketing departments and message boards such as the one we're on now. It's our job whether or not to clean up the mess.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FredoSP &raquo;</TD></TR><TR><TD CLASS="quote">John your right, but what ive learned in the game is that everything is RELATIVE to something else. </TD></TR></TABLE>

exactly, to look at HP alone w/ out looking at boost would be just as bad as looking at boost w/ out hp. You need them both to properly judge a product or tune an engine.

One pet peave of mine is when people are set on achieving a high hp # at a low boost level.... Like its gonna run better then the same hp # at a higher boost level. People forget to consider turbo lag, streetability, and area under the curve in hopes for high hp @ low boost.

 

thats why i say if it takes 30psi to get 500whp so what who cares you got 500whp

 

Whats the difference between 15 PSI through a T25 or a T100 if the intake charge can be made to be the same temperature? We're talking theoretically...

Discussion time, Gentleman...Tony1, chime in soon

Suprdave

 

Umm BOOST MATTERS!!! you blow stock engines if you boost more than 9 psi. Thats a known fact.. you guys are a bunch noobs

 

ROTFLMAO!!!!!!!!

 

What would be a better universal term to describe boost then? CFM?
y0 im boostin 850 CFM!

 

I hate that **** too... All my friends that drive cars with smaller stock turbos than my T3/T4 think they are "faster" because they boost more. They really don't understand the concept at all. It's like people that are disappointed because I don't have VTEC in my LS. Yes, your S4 boosts more than my Integra...

 

well i really am a noob but i have a question although im not sure how to word it. im going to use my car for an example, prelude h23. The ringlands are notorious for blowing at 7-8lbs of boost. if i ran a smaller turbo at 8psi and a medium turbo at 5psi and got the same horsepower... would it be putting the same stress on the ringlands? on the engine? all around... if the airflow and cyclinder pressure are the same... would it make a difference between high boost on a small turbo or low boost on a big turbo??? thanx for all the help

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep972 &raquo;</TD></TR><TR><TD CLASS="quote">

exactly, to look at HP alone w/ out looking at boost would be just as bad as looking at boost w/ out hp. You need them both to properly judge a product or tune an engine.

One pet peave of mine is when people are set on achieving a high hp # at a low boost level.... Like its gonna run better then the same hp # at a higher boost level. People forget to consider turbo lag, streetability, and area under the curve in hopes for high hp @ low boost.</TD></TR></TABLE>

Amen. One thing that also gets me is people who say, no matter the situation; "just put in some low comperssion pistons and run higher boost". Stupid idea IMHO. I'd rather run 9.5:1 and 10 psi than 8.0:1 and 15 psi. The turbo will spool more quickly and your power off boost will be better.

 

I dont want to be a dumb newb so Im reading a lot. But there's so much terminology that I don't understand..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep972 &raquo;</TD></TR><TR><TD CLASS="quote">

high hp # at a low boost level.... .</TD></TR></TABLE>

You gotta look at this, and overall Engine Efficiency.

"PSI" is just restriction of the intake, SO!

The 'less' restrictive the intake path is, the more horsepower you make @ a given 'boost'. Other things come into consideration such as Turbo Size, etc...but that is only because of turbo efficiency and how much heat the turbo produces @ a certain boost level. Colder Air = More Power, which is why you can get away with leaner mixtures, etc. with a larger turbo.

 

People **** there pants around here when i tell them i run 1 bar on a stock block I usually get the stock honda motors can only handle 7-8psi (what the hell does that mean? )respond

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92lSilude &raquo;</TD></TR><TR><TD CLASS="quote">well i really am a noob but i have a question although im not sure how to word it. im going to use my car for an example, prelude h23. The ringlands are notorious for blowing at 7-8lbs of boost. </TD></TR></TABLE>

Well, we can stop it right there. That's an incomplete equation - its more like on typical t3/04 setups, 7-8psi yeilds approximately 250whp, about the limit for the stock block

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">if i ran a smaller turbo at 8psi and a medium turbo at 5psi and got the same horsepower... would it be putting the same stress on the ringlands? on the engine? all around... if the airflow and cyclinder pressure are the same... would it make a difference between high boost on a small turbo or low boost on a big turbo??? thanx for all the help</TD></TR></TABLE>

assuming intake temps are the same, cylinder pressure is cylinder pressure, so yes. I assure you the 8 psi of pressure in your intake manifold is piddly in comparison to the pressures generated by combustion.

 

How ironic....I'm always saying this....Sometimes I tell people 5 psi, for the simple point of they will say is that all....The old saying is true an idiot is born every second...

 

i just know with my stock ringlands i cant run 8psi... but i see these people makin 250+whp on there H23's with like 6.5psi t3/to4e .63/.60 60trim and i was thinkin horsepower is horsepower... whether you run 14psi on a t25 or 6psi on a t4... shouldnt 250whp put the same stress on the engine and ringlands either way?