Good start for forced induction
Thread Starter
Instructor
Joined: Mar 2005
Posts: 208
Likes: 0
Originally Posted by Baldturbofreak
Even the max trim on that page will be jumpy and a bit restrictive.
http://www.precisionturbo.net/turboc...tegory_id=3028
The one at the top of the page will be perfect for you. It won't start making big boost/power until your in second or third. that way you won't skate all over the highway.
http://www.precisionturbo.net/turboc...tegory_id=3028
The one at the top of the page will be perfect for you. It won't start making big boost/power until your in second or third. that way you won't skate all over the highway.
Boost not kicking in until 2nd or 3 is turbo lag...right?
Drifting
Joined: Nov 2003
Posts: 1,637
Likes: 2
From: Honeoye Ny
no, turbo lag is the time it takes for you to build boost when you ask for it. (floor it) that's within the rpm range that it builds boost in.
Boost threshold- is the minimum Rpm that the turbo will make boost under full load.
The big 88 won't really make more than a half dozen or so PSI in the lower gears because you simply won't load the motor hard enough to effect a boost condition. Trust me, this is a GOOD thing. A thumper is as close as you can get to "free boost". It has the leasst amount of backpressure (or T.urbine I.nlet P.ressure) for a given Manifold inlet pressure. If your careful with component selection, alot of times your MIP/TIP ratio will be positive and horespower sky rockets This is called crossover and is the "holy grail" for turbo people.
What Im getting at here is, with a thumper even a mild sbc will make big hp at only a half dozen or so psi, because it's so effecient. When you get to the higher gears it loads the engine hard enough to build AMAZING torque, like it feels like 2nd gear again. Since your in 4th (1:1) it won't break the rear end with the 1000ftlbs of torque it will be making, as the rear end sees that regularly in the lower gears, due to torque multiplication.
Another bonus is streetable traction, 550-600 in first is about all you can hook, being ginger with the pedal, the last thing you want is full boost by 3k in first from a small turbo. It will drive jumpy at part throttle, and if you leave with slicks you can kiss the rear goodby.
IF you used an auto- you would leave with boost. All you have to do is foot brake it to load the motor. since the loading from an auto is more linear, the rear might stay together.
But back to your original question, I have several datamaster logs from Bruce's Rear mount 85mm thumper. It shows gear channges that go frm 12 psi to 27 in of mercury back to 12 psi in less than a second. Instant boost, you just gotta have load. Put 2.59 gears in the rear end, then you'll have boost in 1st and 2nd. Get great milage, too.
Boost threshold- is the minimum Rpm that the turbo will make boost under full load.
The big 88 won't really make more than a half dozen or so PSI in the lower gears because you simply won't load the motor hard enough to effect a boost condition. Trust me, this is a GOOD thing. A thumper is as close as you can get to "free boost". It has the leasst amount of backpressure (or T.urbine I.nlet P.ressure) for a given Manifold inlet pressure. If your careful with component selection, alot of times your MIP/TIP ratio will be positive and horespower sky rockets This is called crossover and is the "holy grail" for turbo people.
What Im getting at here is, with a thumper even a mild sbc will make big hp at only a half dozen or so psi, because it's so effecient. When you get to the higher gears it loads the engine hard enough to build AMAZING torque, like it feels like 2nd gear again. Since your in 4th (1:1) it won't break the rear end with the 1000ftlbs of torque it will be making, as the rear end sees that regularly in the lower gears, due to torque multiplication.
Another bonus is streetable traction, 550-600 in first is about all you can hook, being ginger with the pedal, the last thing you want is full boost by 3k in first from a small turbo. It will drive jumpy at part throttle, and if you leave with slicks you can kiss the rear goodby.
IF you used an auto- you would leave with boost. All you have to do is foot brake it to load the motor. since the loading from an auto is more linear, the rear might stay together.
But back to your original question, I have several datamaster logs from Bruce's Rear mount 85mm thumper. It shows gear channges that go frm 12 psi to 27 in of mercury back to 12 psi in less than a second. Instant boost, you just gotta have load. Put 2.59 gears in the rear end, then you'll have boost in 1st and 2nd. Get great milage, too.
Thread Starter
Instructor
Joined: Mar 2005
Posts: 208
Likes: 0
how did you run the outlet from the turbo to the motor on Bruce's rear mounted turbo?
***********Any of the supercharger crowd have any input on forced induction with the Brodix 18* top end?****************
***********Any of the supercharger crowd have any input on forced induction with the Brodix 18* top end?****************
