Well I just got back from the Dyno and here are the results. 435hp/442tq on my first and only pull because the driveshaft broke in 2 pieces. :( Also the driveshaft completely smshed my Corsa muffler so that also sucks. Other than that the engine ran great considering the conditions 91deg and 70% humidity. I'll post pictures and the video later when I stop crying.

Nice, any pics of the graph

Yea I'll get one posted later, I am doing research on new driveshafts right now.

Ouch! That sucks!
I hope mine hold up.

wonder if corsa would take pitty on you if you sent the muffler back to them and cut you a deal on a new one

wonder if corsa would take pitty on you if you sent the muffler back to them and cut you a deal on a new one

Thats what I am hoping for, I'll be calling on Monday to find out.

Damn Brad! You can't get a break (sorry :jest: ). Very nice numbers though........ Were you going to have the PCM retuned for WOT fueling on the dyno?
Probably ought to check the trans output shaft to be sure it didn't get bent.
Sorry about your woes Brad. Let me know if there's any thing I can help with.

Good luck,

Richard :)

Yea I checked the trans output shaft last night among other things and that looks good. When the driveshaft broke the part going into the transmission came out right away, I may put a new seal in just incase. It seems like I have bad luck but I know some people who have lost kids, have bad health that would trade me lives any day. I am fortunate that it happened on the dyno and not on the track, I am also fortunate that the driveshaft didnt rip a hole in the fuel tank. Is there anything else that I might want to consider upgrading ex: axles? Hey Richard, What did you mean by "Were you going to have the PCM retuned for WOT fueling on the dyno"? Let me know. Thanks.

It seems like I have bad luck but I know some people who have lost kids, have bad health that would trade me lives any day. I am fortunate that it happened on the dyno and not on the track, I am also fortunate that the driveshaft didnt rip a hole in the fuel tank.

:hail: Man, that's a positive attitude! Very true.

Hey Richard, What did you mean by "Were you going to have the PCM retuned for WOT fueling on the dyno"? Let me know. Thanks.

I was refering to tweaking the PE (power enrichment) tables to get the air/fuel ratio optimized. Did they put on O2 sensor in the exhaust pipe when you dynoed?

Richard :)

They were going to but I already had a bung for my wideband gauge that I use with EFI Live. I logged my A/F ratio during the run and it was at 12.0-12.1 @ WOT so I think that is pretty good. Also my timing was at 22 deg @ WOT so I need to do some research if that is to high or to low? I need to talk to Blownchevy or Moregrip about optimal timing with the Radix. When I ran the 12.9 sec 1/4 mile I only had 13 deg @ WOT. I will be giving you a call this winter about the 90mm TB upgrade that you have, Also do you a program worked out for the 6.0L w/Radix? I will be buying an engine soon so I can start building it up so when my 5.3 gets takes a crap I can drop in the newly built 6.0 along with the Radix. Let me know. Thanks, Brad

Here is the Dyno Graph

Here are some pictures of the damage from the driveshaft breaking. I sent the pictures of the smashed muffler to Corsa in hopes that they will give me a good deal on a new muffler instead of the whole system. As far as the driveshaft is concerned, I am getting one built by Dynotech Engineering in MI. I also have driveshaft loops on order aswell.

I can't tell from the pic ( i am pitiful), you a 2 piece? Is that a carrier piece or the actual carnage. Man, sorry to hear you broke the shaft. What gear were you in? rpm?

only 13* for the 12.9? Wowser! You got some room to grow. I'd say. Plenty of research on here for the shaft. I have steel one (3") that I had custom made for my 4l80 swap. It's probably 69" or so. PM me if you want it.

NICE Dyno sheet! Congrats on the numbers.

I was in 3rd gear with the convertor unlocked, I was at 5850rpm when the driveshaft broke. Well I did have a 1 piece driveshaft but not anymore of course. I just called up Dynotech Engineering and told them what I had done and gave them all of the correct measurement and they said they will build me a driveshaft that will not break! Yea I didnt check the timing until last night and that is when I noticed what my timing was on the 12.9 run compared to yesterdays dyno run. As soon as I get my truck back together I will head back to the track and see what my truck can do. I am also working on those videos for you, I have one of my truck on the Dyno when it broke the driveshaft. I'll post it on here as soon as I get back tonight. Later.

I am also working on those videos for you, I have one of my truck on the Dyno when it broke the driveshaft. I'll post it on here as soon as I get back tonight. Later.

that'd be cool...not that you liked it, but a cool vid nevertheless eh?

Here is the video of the Dyno run when the driveshaft breaks, Enjoy.

http://video.performancetrucks.net/video/8613a778-bf05-43d2-bdb8-980e017f1a2e.htm

I ordered my new driveshaft from Dynotech Eng. and they recommended a 4" Steel DOM driveshaft for my truck. They said that the driveshaft is good up to 8000rpm which I think is plenty good. I also called Corsa Performance and they are selling me just a muffler, They had to call Tbyrne to confirm that I bought it and they want me to send back the smashed muffler so they can scrap it. All in All I am very happy with everything so I should have my truck back on the road by Friday.

kool!

a 4" steel?! wow, how much does that f-er weigh?

I dont know, The guy told me that the steel DOM is what he would buy if he was in my shoes so I will take his word since that is all he does is work with driveshafts. BTW the video is looking good! Later.

Ouch, what mph were you at on the dyno when the shaft came apart? A couple hemi owners have had there's gernade on them when running 122mph+. Long drive shafts like the ones on a truck at those speeds can flex too much and gernade.

It broke at 119mph according to the Dyno graph. I could feel the truck starting to vibrate during the dyno run but I didnt think that my driveshaft was going to break.

I saw this picture and had to post it here.

I dont know, The guy told me that the steel DOM is what he would buy if he was in my shoes so I will take his word since that is all he does is work with driveshafts. BTW the video is looking good! Later.

That looks like Naked AV's driveshaft when his let go.

I have the stock 2pc dana-spicer 3.5" steel driveshafts and they are safe to 6300/7000 rpm respectively according to dana-spicers critical speed chart and my local driveline shop. the 4" DOM reccomendation sounds like a good one to me

It broke at 119mph according to the Dyno graph. I could feel the truck starting to vibrate during the dyno run but I didnt think that my driveshaft was going to break.
You should do a little more than just replacing the driveshaft if you had vibration problems prior to it letting go.

I had a pinion angle problem that caused my driveshaft to let go at 141 mph on the dyno...but what's interesting about that is, I had noticed some vibration at 70 mph ever since I lowered the vehicle.

If your shaft let go at ~120 mph, let me ask - did you notice vibration at 60 mph, however slight? They are harmonics of each other, which means that a vibration at 60 mph reappears at 120 mph, only worse.

Make sure you don't have a pinion angle issue. The results next time with a steel shaft might not be so pretty.

http://s89728284.onlinehome.us/cobra/PICT0006.JPG

Yea I did not check the pinion angle after I installed the Hotchkis 2-4 drop but I will be checking it after I get the new driveshaft installed. To tell you the truth I didnt really notice any vibration except for when I got up to about 110 and then I felt a slight vibration. Thanks for the heads up, I heard that the pinion angle should be between 5-7 degs? Let me know if this is true. BTW, What kind of driveshaft did you get?

Yea I did not check the pinion angle after I installed the Hotchkis 2-4 drop but I will be checking it after I get the new driveshaft installed. To tell you the truth I didnt really notice any vibration except for when I got up to about 110 and then I felt a slight vibration. Thanks for the heads up, I heard that the pinion angle should be between 5-7 degs? Let me know if this is true. BTW, What kind of driveshaft did you get?
The pinion angle should be opposite and equal to the angle of the transmission output shaft. For example, if your transmission output shaft faces downward at 5 degrees, then your pinion should face upward at 5 degrees.

When I finally had my angles looked at (well after my 2/3 drop and right after the driveshaft blew up), my transmission output shaft aimed down 4 degrees, but the pinion aimed up at 7 degrees. This fully explained the driveshaft incident.

After installing longer lower control arms (I had a 5-link in the Avalanche), the new pinion angle was then down 3 degrees. This was actually ideal, since applying Radixed torque actually moves the pinion up a degree or so, making the angles equal (4/4) under heavy torque load.

I ended up getting a stock replacement driveshaft. With the pinion angle correction, there was no problem after replacement.

Hope this helps. Definitely get it looked at by a shop that knows what they're doing.

The pinion angle should be opposite and equal to the angle of the transmission output shaft. For example, if your transmission output shaft faces downward at 5 degrees, then your pinion should face upward at 5 degrees.

When I finally had my angles looked at (well after my 2/3 drop and right after the driveshaft blew up), my transmission output shaft aimed down 4 degrees, but the pinion aimed up at 7 degrees. This fully explained the driveshaft incident.

After installing longer lower control arms (I had a 5-link in the Avalanche), the new pinion angle was then down 3 degrees. This was actually ideal, since applying Radixed torque actually moves the pinion up a degree or so, making the angles equal (4/4) under heavy torque load.

I ended up getting a stock replacement driveshaft. With the pinion angle correction, there was no problem after replacement.

Hope this helps. Definitely get it looked at by a shop that knows what they're doing.

Thanks for the info, I will have somebody who knows what they are doing check it out.

Amazining how quick you got out of it,no over rev.

Here is a picture of the new driveshaft. Dynotech 4" Steel DOM.