a/r numbers

Marty · Post by **Marty** » Mon Feb 11, 2002 5:39 pm

By the way, Robert Hemphils motor builds some boost without a load. He has a very expensive ball bearing turbo that is sized perfectly to his motor. He does not use a limiter to leave the line. He revs it up and it spools up. There is not a better street car combo that I have ever seen.

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Marty Staggs

www.staggsracing.com

sventek · Post by **sventek** » Mon Feb 11, 2002 7:04 pm

Man, the topic got lost quick! Oh well, thanks for the info on the first few posts.

MagOO · Post by **MagOO** » Mon Feb 11, 2002 11:16 pm

Years ago I had a corvair turbo And to build boost I would drag the brakes under heavy throttle to the line .If you were leaving shortly after you staged you were good to go..But a thirty second delay and you were dead meat... The turbo world has come quite a way since velvetouch brake shoes and the OEM Corvair Turbo muffler from GM being the best ...period!

MagOO · Post by **MagOO** » Mon Feb 11, 2002 11:18 pm

Anyway,The T3 from a Saab 900 w/ .48 a/r should work well in your application or even an older b flow Rajay..

cam509veedub · Post by **cam509veedub** » Thu Feb 21, 2002 6:22 am

i have a TEO4H turbo from a chrysler 2.2. i have looked for the a/r numbers for this turbo. i am not even sure what to do if i found them! is this turbo decent enough for a 1915 with 044 heads?

Tracy · Post by **Tracy** » Thu Feb 21, 2002 9:12 am

I believe you guys are on the right track, but the exact reason a turbo reaches operating speed is not load or RPM specifically. It is exhaust gas pressure, plain and simple. My shop uses a Redat VSR machine to test final balance on assembled turbos, and all it uses is a huge tank of compressed air to spin even medium frame turbos to 100,000 RPM and more. Obviously both RPM and load will affect the exhaust gas flow on an engine, but there are other ways to do it as well. You can use a rev limiting system such as the MSD soft touch which randomly removes sparks as the limit is reached - the throttle plate(s) can remain wide open, allowing maximum airflow at the limit RPM. The only thing that will reduce your boost at that point is the reduction of exhaust gases due to lack of thermal expansion in the cylinders that don't get lit. If you have enough EGT and a way to manipulate the mixture, there is a way to get the unburned gases to actually light in the exhaust however

WAHOOO instant boost and makes the guys on the starting line duck too LOL. This is how I make my car work.

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"there is no substitute for positive manifold pressure"
Tracy Grimm
www.tgfab.com

Steve Arndt · Post by **Steve Arndt** » Thu Feb 21, 2002 1:28 pm

<BLOCKQUOTE>quote:<HR>Originally posted by MagOO:
Years ago I had a corvair turbo And to build boost I would drag the brakes under heavy throttle to the line .If you were leaving shortly after you staged you were good to go..But a thirty second delay and you were dead meat... The turbo world has come quite a way since velvetouch brake shoes and the OEM Corvair Turbo muffler from GM being the best ...period! <HR></BLOCKQUOTE>

I was hotrodding around in a 2000 TDI Jetta last week. If you lug in first and try to hold the brake to build boost the ECU thinks you are two footing it (I was) and it SHUTS down the engine

I almost got smashed in an intersection

Steve

Steve Arndt · Post by **Steve Arndt** » Thu Feb 21, 2002 1:34 pm

It is also how 4 cylinder 2 liter rally cars leave the starting line at 33 PSI and 390 horses! pop pop pop!
Stevie

<BLOCKQUOTE>quote:<HR>Originally posted by Tracy:
I believe you guys are on the right track, but the exact reason a turbo reaches operating speed is not load or RPM specifically. It is exhaust gas pressure, plain and simple. My shop uses a Redat VSR machine to test final balance on assembled turbos, and all it uses is a huge tank of compressed air to spin even medium frame turbos to 100,000 RPM and more. Obviously both RPM and load will affect the exhaust gas flow on an engine, but there are other ways to do it as well. You can use a rev limiting system such as the MSD soft touch which randomly removes sparks as the limit is reached - the throttle plate(s) can remain wide open, allowing maximum airflow at the limit RPM. The only thing that will reduce your boost at that point is the reduction of exhaust gases due to lack of thermal expansion in the cylinders that don't get lit. If you have enough EGT and a way to manipulate the mixture, there is a way to get the unburned gases to actually light in the exhaust however

WAHOOO instant boost and makes the guys on the starting line duck too LOL. This is how I make my car work.

<HR></BLOCKQUOTE>

BOYZ TOYZ 007 · Post by **BOYZ TOYZ 007** » Thu Feb 21, 2002 3:13 pm

i would like to put my two cents in and kick a dead horse . i have a turbo kit from banks on my tow truck . it will produce 33 psi at full pedal ( in any gear ! ). and i can be on fast idle and have 5 psi . i my self am a smart ass . but at least i dont call someone a dumb ass when i myself don't know what i am talking about .and do it hiding ! i enjoy this forum and look forward to it each tim i log on . but when you say things just to be a part of the forum . well it says alot about who you are . just my two cents .......

panel · Post by **panel** » Sat Feb 23, 2002 9:51 pm

<BLOCKQUOTE>quote:<HR>Originally posted by panel:
 I don't even see boost in first just late in 2nd and lots in 3rd when theres lots of load forth in the bus under full boost is too fast for me in the van.
<HR></BLOCKQUOTE>
So is there something wrong with my turbo design? Why do I not see pressure at idle? And why do I not get any boost(BARELY) in first gear? I have a small b-25 turbo.Is there a restriction in my intake? I highly dought it...it seems to smooth of a transition from the turbo to the heads?

Searoy · Post by **Searoy** » Sat Feb 23, 2002 10:23 pm

You don't want to see presure at idle unless you designed it that way for a reason. Boost at idle would mean you have a SEVERE restriction in your intake. You should only see boost at wide open throttle, and even then the end of second and going into third is a good place for it.

Just remember where you boost sensor is located. That's where it measures the pressure. If it's where it belongs it's in the intake manifold pretty near the ports. If it measures pressure there, then pressure is not getting into the chamber.

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*** Teach a Man to Fish ***
Searoy

"I tend to lean toward a tighter gap and a
looser skirt....a little slap never hurt." -- Joe of the West

MagOO · Post by **MagOO** » Sun Feb 24, 2002 7:38 am

Panel. just a guess , but I think you don't show boost in low be cause in a bus first is so low it uses gearing to get up to speed and then the turbo is operating and making power...I would almost bet that if you found a steep hill and tried to start out and climb in first, that the boost fella magically appears.. Let us know...Dan