10 PSI on an automatic
04-26-2010, 01:01 AM
#1
2nd Gear Member
Thread Starter
Join Date: Nov 2008
Location: British Columbia
Posts: 194
10 PSI on an automatic
I am currently running an 8lb pulley on my automatic Whipple Gen 1. I am getting 402 RWHP on A Dynojet A/F 11.7 avg.What would 402 RWHP be at crank hp. I am going to put on a 10 psi. pulley. With parasitic loss where is my safety margin. I know I am not too close but can any body tell me what numbers I would be seeing at the crank.Everybody talks about RWHP when talking blown rods pistons etc.Are they talking stick... auto... what? Are they taking into consideration of the losses we auto's lose? Can someone explain where an auto starts to get into dangerous numbers.THX
04-26-2010, 06:41 AM
#2
3rd Gear Member
Join Date: Jan 2005
Location: Chesterfield, Virginia
Posts: 525
I'm running 11 psi and an automatic. No problems other than the dreaded third gear servo problem. Your mileage may vary but I have had no issues with this amount of boost and my auto. I'm pushing in the low 500's for HP. A converter will take a lot of pressure off the rods as will a 3.73's or a 4.10 gear. A lot of people throw rods as the engine shifts into 4th under a lot of boost. Liddio Lacabeli (Spelling?) threw his rods out in forth but he had over 80 strip runs with 17 psi and stock 3.31 gears.
04-26-2010, 02:16 PM
#6
6th Gear Member
Join Date: Jan 2008
Location: North Pole
Posts: 6,716
you can replace just that sychro, but it's an involving process just to get to that one gear. I know it's apples to oranges, but over at the university, when working on the M5OD- you literally have to take the entire thing apart just to get to that "one" part. And it's not just that one synchro, it's the entire assembly. If the instructor lets us, when it's time to do auto tranny class, I want to install after market input/output shaft, as well as a better 3rd gear sychro assembly. Its quite a bit of work.. I'll see if I can post pics up later...
04-26-2010, 02:21 PM
#7
2nd Gear Member
Thread Starter
Join Date: Nov 2008
Location: British Columbia
Posts: 194
So epic failure(pistons rods etc) is based on whatever RWHP and RWTQ the car is making not the motor itself.Taking parasitic loss out of the equation. td1320.... as I am nowhere near that hp I don`t have to worry.THX
04-26-2010, 04:55 PM
#10
3rd Gear Member
Join Date: Jan 2005
Location: Chesterfield, Virginia
Posts: 525
Correct, and you can change them out with a TCI Billet without taking the whole thing apart. Forth gear in this automatic puts a big load on the engine compared to 2nd or 3rd. With large amounts of boost it spells disaster for the stock rods. I also put a hardened input shaft in my tranny since I had it out for the converter.