not quite what I'm looking for but maybe someone might want this??

http://cgi.ebay.com/ebaymotors/ws/eb...517766&r=0&t=0

 

Those do not seem like hi proformance turbos, the max psi is 12.

thanks for the link though, I like the pics

:hail: :hail: :hail:

 

12 psi isn't enough for you?

 

I just don't think it is high proformance. Am I wrong?

 

I don't know much about turbo systems, but 12 lbs is about average from what I thought. Most cars with turbos will come stock running only a few pounds, my dads power stroke diesel only runs about 8 pounds of boost, and its enough. An old boss of mine had a Grand National that was running around 14 pounds of boost and that was just sick, especially for a 6 cylinder...

-=-Mike

 

thats what I found. I thought that 12 lb of boost is like the starting level for aftermarket turbos.

 

That would still provide a SUBSTANTIAL gain on your car I bet.

Go for it.

Even the banks ones can handle around 800hp. According to hersay. Hard to say what they could really do. That is a LOT of power.

 

I don't suppose anyone has a copy of the Twin turbo vette built by Lingenfelter do they? I think it was in an issue of Car and Driver. That car got going so fast that the hood rippled (I think that was around 200+). I was looking on the net and couldn't find the article. I don't think he was running much over 14 lbs of boost though.

Guido, hows the project coming along?

-=-Mike

 

also guido maybe you could educate us.

Its my understanding that the amount of boost will depend partly on the size of the turbo, e.g. a smaller turbo will have to run more boost than a larger turbo in order to make the same amount of power but the bigger turbo will have a greater amount of lag. Am I right?

-=-Mike

 

use this as an analogy.

if I had an engine that was say 100 CI. I put a turbo on it & it was making 100 HP, & it had 20 PSI of boost.

Now I put that same turbo onto an 800 CI, engine, the boost is going to drop to next to nothing. is the 800 CI engine going to make more HP than the 100 CI engine? Probably.

Is the turbo right for the 800 CI engine, NO. does the amount of boost mean much.............. Yes if taken in context.

this is kind of line the blow through a straw & blow through a Dryer vent tube.

on an engine with medium quality heads, the right cam & about 350 CI, THAT turbo setup will make decent HP. but by using a Carb drivability is not going to be the best. get a slightly better turbo & it is goign to make good HP. but with the exh design it is going to be limited to about 600 HP (even with a GREAT motor). this is becuase we are breathign through a straw again.

Good starter point, yes. but know what you can do with it........ & what you are going to get out of it.

my2c.
BW

 

Well, here are the latest photos of the setup.

 

drool!!! :hail: :hail: :hail:

I was once told that around 15 psi would equate to a 100% increase in power but I dont know if that statement is correct.

 

15 psi is atmospheric pressure....so parasitic drag, heat, and other variables aside that is a true statement.

 

Thanks for the pics

 

trux,

To answer your question. The larger the turbo the more it will lag on a small application.

Turbos use what are called maps. These are sexy little pieces of paper of which I am still learning to read. Factors involved in determining the best turbo for the appication al depend on the size of the turbo being installed. A Garret T-28 is a good overalll size for a 4 cylinder engine for stock boost evells of 6-8 psi, and will run out of useable energy by around 12 psi if a boost controller is put inline with the wastegate acctuator. putting a T-3/T4 hybrid turboo on the same engine will create a lot more horsepower but requires a longer wait tilll the turbo gets to its sweet spot to produce the boost required. this is an example on a 4 cyl.


T-28 2400 RPM begins building boost Booost is at full pressure by 2800-3200 rpm

T3/T4 hybrid 3400 RPM begins building boost and is fully in by 3800-4100 rpm

But what you have to look at is not only how much boost you are producing but the cubic feet of air the turbo is aable to move efficiently @ the pressure.

T-28 @ 12 psi of boost = 600cfm

T3/T4 hybrid @ 12 psi of boost =850cfm.

These are just examples they are not correct numbers they were used to show the differences in the lag and airflow.


All of these numbers are affected by temperature, exhaust housing size, compressor housing size, piping restrictions, and exhaust restrictions.

Sizing a turbo to an appllication is not like going out to get a set of wiper blades for your car. It takes a little research and a lot of patience with an expert on the phone.



Sean

 

Thanks for explaining that:hail: :hail: :hail:

I had a little bit f udnerstanding but things are more clear now.

 

I have the definitive book on turbocharging. The optimum psi is about 18 for road racing. Thats only if you can keep your temp low. As temp increases the auctual power increase decreases drastically due to the expansion of the air therefor, you have 2 options, control your heat, or more boost.

 

15 psi of boost is not atmospheric pressure.

 

atmospheric pressure is between 25 and 40 psi. Supercharging in above the atmospheric pressure though. The atmosphere is used as the baseline.

 

for the most part at sea level atmoshperic pressure is at about 30 psi.

 

I'm not sure what planet you live on, but here on Earth at sea level, standard air pressure is 14.7 psi absolute.

A "perfect" vacuum is at 29.92 inches of mercury. There is about 2 inches of mercury for every 1 psi.

 

...or 760 torr, 760 mmHg, 101325 Pa, 1013250 dynes/cm^2.....:lala:

 

I just copied this from the weather channel site for my area.

Barometer: 30.29 inches and falling

It is failing because a storm is coming into my area, but he pressure is normally arouns 31.

 

That is measured by a barometer. They scale in inches of mercury.

Atmospheric pressure IS 14.7 pounds per square inch.

http://kids.earth.nasa.gov/archive/air_pressure/

Read that link.

I still cant figure out how the two are related although is sounds like a barometer measures air pressure.

Funny.
Anyone here a science or meteorology major?

 

I am a computer science major, I was just trying to remember stuff from high school chem, I thought that was true, sorry :hail: :hail: :hail: :hail:

 

Thats inches of Mercury. Whoops, Guido beat me to it. And Trux already replied? Damn, you on here 24hrs a day or something?

 

30.29 inches of mercury x (25.4 mm mercury/1 inch mercury) = 769.366 mm mercury. A standard atmosphere is 760 mmHg. Or 14.7 pounds/square inch (psi) or 1 atm, or 1 bar. I think you just got your units a little confused. There's a bazillion different units to measure pressure.

 

1.000 atm = 1.013 bar

 

oops!!

 

MAPS are a BIATCH to get used too. But FLOW maps are pretty easy. It's just matching your desired PSI to a turbo that will do it with out many mods... getting your exhaust flow is another challenge. The exhaust turbine is one of the hardest things to tune. The intake is easy. Its the MAX PSI you want.... But it also requires some info from the turbine side..

 

Bar is a Meteric determination of PSIG. 14.7 is N/A 1 PSI. Meaning 2 bar is 14.7X2= 29.5 BAR Or something like that....

 

No, 1.0000 Bar is 14.50377 psi

A Bar is close to an atmosphere, but it is not the same.