question on boost with auto..
12-31-2007, 02:45 AM
#1
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question on boost with auto..
how much whp does and the auto rob? I was thinking,if a sc makes 9psi to the wheels but is getting robbed about 15whp,would it makes sense to up the boost to make up for that loss of power or does it not work like that? being that 9-10psi is still the limit of what the stock motor can make regardless of what it's putting out to the wheels,auto or not??
12-31-2007, 03:19 AM
#2
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RE: question on boost with auto..
It's not robbing 15 hp. It's a percentage. So if your auto looses 15-20% from the motor, it should be similiar or less after you apply and S/C. The boost is the pressure built in the air intake between the throttle body and the S/C. You should have no problems getting big power to the ground with the auto. They are able to hold big power if tuned properly and retro fitted with stronger clutch bands. Tuned properly, your auto willlast longeron more power before your motor blows.
12-31-2007, 11:35 AM
#5
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RE: question on boost with auto..
Brent's 5R55S tranny blew when he was running his first built turbo motor, which also blew on the dyno. He now has a Lentech 4R70Win that car. An automatic trans loses 15-20% of it's total power due to how an auto tranny works. Whoever said 9-10 PSI is the limit for the stock block? I have been running 11 PSI and never had any issues. There are lots of guys at 12 PSI and even higher on turbos.
Regardless of what transmission is behind the engine, the limitations on the stock lower end are the weak rods and pistons. If you have detonation it will make no difference if the engine is turning an automatic or manual tranny.
Regardless of what transmission is behind the engine, the limitations on the stock lower end are the weak rods and pistons. If you have detonation it will make no difference if the engine is turning an automatic or manual tranny.
12-31-2007, 12:12 PM
#6
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RE: question on boost with auto..
The weak link in our auto trannies is 3rd gear. I would change the ATF to Amsoil, and avoid doing too many highway 3rd gear drops and you should be fine. JDM is still running the stock 5R55 tranny in their blue car which just hit the 9's in Nov and Jim Jr is running the stock tranny behind a new TCI custom converter and is consistently in the 10's. Since I want my car to last I try not to beat on her too much, and will be changing the ATF to Amsoil in the Spring once out of storage. My converter has made such a world of difference in the performance level, that it has been able to postpone the inevitable urge to up the boost.
12-31-2007, 02:08 PM
#7
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RE: question on boost with auto..
ORIGINAL: drbobvs
The weak link in our auto trannies is 3rd gear. I would change the ATF to Amsoil, and avoid doing too many highway 3rd gear drops and you should be fine. JDM is still running the stock 5R55 tranny in their blue car which just hit the 9's in Nov and Jim Jr is running the stock tranny behind a new TCI custom converter and is consistently in the 10's. Since I want my car to last I try not to beat on her too much, and will be changing the ATF to Amsoil in the Spring once out of storage. My converter has made such a world of difference in the performance level, that it has been able to postpone the inevitable urge to up the boost.
The weak link in our auto trannies is 3rd gear. I would change the ATF to Amsoil, and avoid doing too many highway 3rd gear drops and you should be fine. JDM is still running the stock 5R55 tranny in their blue car which just hit the 9's in Nov and Jim Jr is running the stock tranny behind a new TCI custom converter and is consistently in the 10's. Since I want my car to last I try not to beat on her too much, and will be changing the ATF to Amsoil in the Spring once out of storage. My converter has made such a world of difference in the performance level, that it has been able to postpone the inevitable urge to up the boost.
and how is this limitation overcome?? stonger after market parts?
totally giving away noobness by asking this but what exactly is the 56R55?? lol
12-31-2007, 02:12 PM
#8
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RE: question on boost with auto..
what do you mean by 3rd gear pops? you mean just avoid flooring it around 65 or so on the freeway
and how is this limitation overcome?? stonger after market parts?
what exactly is the 56R55?? lol
12-31-2007, 03:55 PM
#9
3rd Gear Member
Join Date: Jul 2007
Location: South Carolina
Posts: 921
RE: question on boost with auto..
I will let everyone know when my trans goes. I run 11.5 pounds and floor it from 65 about10 times on my way to work and probably more on my way home atleast 4 days a week sometimes more. I drive atleast 900 miles to work and back a week and beat my car hard. It runs awesome considering i do my own installs. I have 20 K miles with no mechanical problems yet about 15Kare with the supercharger.