I have read about people building boost before a launch and was wondering how much boost can you safely build before taking off on a stock tranny?

 

Ive launched a few times at 10psi in my truck, and ive known others to do the same, but i wouldnt want to go over 10

 

I just did a 10-12 psi launch last night that resulted in a serious outburst of tiresmoke

 

Safely??........ Answer is NONE!

Semi-Safe .....keep it under 8 psi.

There are only two kinds of people that powerbrake OFTEN..... those that have broken input and/or output shafts, and those that will!

Best to never play unless willing to pay. I stayed away from drag racing for 2 yrs till I could afford billet shafts, for that very reason. Not much fun leaving the line at idle, IMO

RJ

 

First launch @ 15 psi


Randy

 

Ask Mike D-He broke a stocker and then broke an Opie output shaft all inside of four months------Unbreakable??? Don't believe it, at some point they will all die a quick death!!

 

What about a standard?

ive left at 30 - 35 psi several times

 

Well I guess I want be trying that then. Thanks for the replies guys.

 

If you don't launch in 4 wheel drive you can only build so much boost before the tires roll smoke. I've broken a couple shafts one stock and one not. It's not a fun experience for the driver nor the people who you have to ask help from. I wouldn't launch a truck with stock shafts over 10 psi. I broke my stocker at around 15 psi.

 

Hey Mike,
You're talkin about input & output shafts, not axle shafts, right?

 

Right, I'm talking about the output shaft of the transmission.

 

What? MikeD did break break one of my outputs. Unbreakable? Never said that. It only has a 1.2" diameter, the best strength I can get out of it is 2200 footpounds in distructive testing. Obviously MikeD's didn't make the grade, and it's replacement was sent out same day.

Out of several hundred outputs sold there have a total of two todate that have broke like Mike D's did. ( I guess my customers over the past three years must be easy on stuff.) Believe this, I do not have a max boost call out. And several others running my output shafts have launched at more psi than black diesel, the only difference being the autos usually tend to be running 12's. (And as we all know a auto is putting out more torq at the same boost when launching.) In most cases the higher boost launches is kind of stupid as it heat soaks the intercooler thus resulting in a slower quartermile time.

I do enjoy drag racing my trucks and do my part to help others be able to do the same. I make, test, run, backup and believe in what I sell. I launch at the boost that gives the best ET, otherwise why bother?

 

Just for clarification. I don't have anything negative to say about Opie or his products. His customer service and product reputation are top notch. I went with Opie's product for reasons given above. I still say anyone wanting to race should run Opie's shafts. If anyone were to get a bad shaft in this whole country it would be me, I have that kind of luck. In the end all a customer can ask from a vendor is that they stand behind what they sell. Opie has done so and in a very timely fashion.

 

[QUOTE=OPIE]Unbreakable? Never said that.[QUOTE]

There are some people who are saying that, and I think some people believe that is the case. I agree with you that with the 1.2" you can only have so much strength there!! Regardless of the material.

 

[QUOTE=Mcmopar;1095572][QUOTE=OPIE]Unbreakable? Never said that.With the exception of shockloading few trucks are clearing 2000 ft pounds of torq. And those trucks can have an option to graduate up to the big boy league of running a IE1480 output which will hold an excess of 3000 ft pounds. Material, processes, and certs is everything. I do not use 4130, 4140, 300M, 8620 or 9310 steel for my shafts though it would be cheaper and easier to do so. Since you can only have so much strength do to size of the diameter is the reason I feel people buy my products.
The competition prices their shafts real close to the price of mine and by doing so must offer a real nice profit margin to the installers. Several guys think that shafts are the same when the word billet is used. I found a nice definition on the internet...Billet is a generic term for a hunk of raw material that has been processed by removing materials to make the final part. Fact is, you can carve a bar of soap and call it your masterpiece billet.

Like I always say, "It's your money."