GSR, b18c. What would be a safe compression ratio, and what is the "stock" ratio???

 

Stock is 10:1

10psi....on what turbo? 10 psi says nothing.

Throw a little more detail and we'll be sure to help you

 

t3/t4 60 and I have heard that 10psi is 10psi, its the consistency that counts. Thats Just what I read it may be wrong.

 

OKay first of all Ten lbs on one turbo, is NOT the same on another turbo. And when you say consistency, your turbo will spool the same everytime. Unless something is changed.

But to answer your question. There are alot of b18c's on H-T that are running alot more than 10 lbs with a 10:1 compression.......but a typically a safe CR would be 9.0:1

 

stock compression ratio is perfect.

 

and 10lbs on a t3/60-1 will make more power than 10psi on a t25

even tho 10psi is 10psi

 

so 10 is actually 10 its just alot more air!!!! iiiii Seeeee

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by alloutmotor &raquo;</TD></TR><TR><TD CLASS="quote">and 10lbs on a t3/60-1 will make more power than 10psi on a t25

even tho 10psi is 10psi</TD></TR></TABLE>

No it's not, your sucking in a lot more air with 60-1. Putting more load and running leaner. More load and leaner means more heat! Readings are same on boost gauge, but still totally diffrent.

10:1 compression is consider pretty high for turbo, but there are a lot of low boost stock compression guys running around here. Higher compression just gives you a higher chance of detonation. If detonation is stop, your chances of blowing **** up is less.

 

Just because two different turbo can compress air at the rate of 10psi, doesn't mean they both flow as much air.

 

i'm saying 10 is 10, But 10 with 60-1 is FLOWING more air than a t3t4. is that right, or no.

 

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

No it's not, your sucking in a lot more air with 60-1. Putting more load and running leaner. More load and leaner means more heat! Readings are same on boost gauge, but still totally diffrent.

10:1 compression is consider pretty high for turbo, but there are a lot of low boost stock compression guys running around here. Higher compression just gives you a higher chance of detonation. If detonation is stop, your chances of blowing **** up is less.</TD></TR></TABLE>

i dont really understand what you are saying in the first sector...

10:1 is a little high..most people boosting run 9.X..but i rather run 10.X, and lower boost. With proper tuning you should be able to eliminate detonation. Also higher compression helps your turbo spool faster, thats always a plus.

 

stock compression, but if you want to leave yourself a little tuning margin then feel free to go down to about 9:1. I wouldn't advise going lower then 9:1 because the drawbacks vastly outway the benefits.

 

10psi on one turbo is the same as 10psi on the next. Air pressure is air pressure.

What you have to think about is that pressure is really an indirect way of measuring the air going into your engine. If there were an easy way to measure volume, you'd have a CFM (cubic feet/min) gauge in your car... since there isn't, air pressure (PSI) will have to do. All of this "10psi on (insert turbo) is not 10psi on (insert turbo #2)" BS is quite indirect. Air pressure is air pressure, 10psi = 10psi in any case or circumstance.

Lets get our terms straight here. 10psi on your t25 is the same as 10psi on my SC61, but the CFM (flow) is where the difference is seen.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MadCow &raquo;</TD></TR><TR><TD CLASS="quote">10psi on one turbo is the same as 10psi on the next. Air pressure is air pressure.

What you have to think about is that pressure is really an indirect way of measuring the air going into your engine. If there were an easy way to measure volume, you'd have a CFM (cubic feet/min) gauge in your car... since there isn't, air pressure (PSI) will have to do. All of this "10psi on (insert turbo) is not 10psi on (insert turbo #2)" BS is quite indirect. Air pressure is air pressure, 10psi = 10psi in any case or circumstance.

Lets get our terms straight here. 10psi on your t25 is the same as 10psi on my SC61, but the CFM (flow) is where the difference is seen.</TD></TR></TABLE>

Please try not to confuse the guy.
Anyways you're wrong there. PSI itself may be the same yes, but it's not just the CFM. It's also the air density. This is where thermo comes in. The more you spin that little t25 the hotter the air will get after it's peak efficiency range. The 60-1 will push the air at a higher rate with greater efficiency at the same psi, and therefor lower temps. What these temps tell us is how dense the actual air that's "chillin'" in intercooler and the manifold is. This says that the cooler your charge is the more air, and the more power you can make off of it with the proper amount of fuel.

I remember you said you were working on a sand rail. I'm assuming you are going to run this Nevada. You might want to decide what kind of fuel you use before you build your set-up. Fuels like Methanol, or Ethanol(personal fav.) cool your intake charge so an intercooler isn't needed. That leaves a wide variety of set-up's available to you. It would also be easier on your engine in such a hot climate. Not to mention lighter, which is good in the hot hot sun.

Anyways I say go for the 60-1 on stock compression. Arturbo can help you out with picking a turbo. Great guy.

 

i'm running 10psi on my stock GSR motor... no problems what-so-ever... i would have been running more boost but i couldnt afford larger injectors and a 3 bar map sensor at the time of tuning.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nd_styles &raquo;</TD></TR><TR><TD CLASS="quote">Please try not to confuse the guy. </TD></TR></TABLE>

The point was not to confuse, but rather to show that the statement about 10psi not being equal to 10psi is just as asenine as it sounds.

 

Excellent reply man, that is an awesome idea. Alternate fuel.hhhmmmm (New Topic)

 

If you want a cheap alternative to replacing pistons to lower compression, Cosmetic makes a "turbo" headgasket that serves the same purpose of o-ringing the motor and lowers compression 0.751 points and is 0.057" thick instead of the stock 0.029".

I'll be running it in a motor i'm rebuilding now.