Rubberduck didn't mention if he held the go pedal long enough to stabilize the temps but if it takes 10-15 seconds then the damage may already done. From what I now..that ain't much, the pistons begin to micro fracture at a certain temp (1250-1300ºF). Every time it gets a little worse until there is a failure....
Ever hear this one:
But, but...my EGT's were only at 1250 for a second or 2...then poooff! They fail to mention the 20-30 times they over-temped before.
I was in one of the trucks when the piston gained a couple extra holes.....ugly...very, very ugly

 

Jim
10-15 seconds? How can it possibly take that long for hot gasses to travel 3 ft from the manifold to the turbo. More like 1 or 2 maybe 3 for the heat to soak into the cast housing. I ran a matched set of ISSPRO thermocouplers and a dual gauge right up until I wiped out the thrust bearings in the stock turbo. One probe was mounted in the manifold and the other was in a nipple I welded into the top of the EBPV housing.

[URL=http://rides.webshots.com/photo/1133205970054971087rGXZaI][



Here's my gauge. That pic was taken with the cruise set at 70 and the temps are so close you can't tell which probe is where.There's a 12 mile grade heading north out of Phoenix and with a little camper on the back and a little trailer behind both needles would read the same till I reached the top.

 

LUCKY!!!!! I've wanted a sandrail my whole life! Never been in one but they look like a lot of fun.

 

cuda, the pistons take a couple seconds (around 10-15) to heat up to the same temperature as the air... the air is a better heat conductor than the metal in the pistons, when the exhaust is at let's say 1200 for the first second and you were cruising at let's say 750 degrees, the pistons are probably only at about 800 in that first second, after 5 seconds it's probably closer to 1050, by 10 it's probably around 1150 or 1200, but it's not instant, but definitely close enough to cause damage if you're not paying attention... BUT on the flipside it also takes the pistons longer to cool down than the air... so if you're towing in the hills it'll shoot up to 1300, back down to 1000 and back up to 1350... when the air is at 1000 the pistons are probably still at 1200 or so... THAT can cause big issues... but in just a short 10 second spurt of 1200, 1300, 1400 degrees you won't have any issues
bluemule, under steady cruising yes the temperatures will be close, but what happens when you're cruising then suddenly gun it up a hill? the gauge closer to the cylinders will heat up MUCH quicker, and at around 1200 degrees the post-turbo one will probably only read 1050 or so... maybe EVENTUALLY it'll get up to that 1200 degrees but by then it's too late or very close to it...

now just to clarify, all these are examples since the melting point of our pistons is actually i believe around 1270-1300 degrees not 1200 but it's always a safe bet to keep it below 1250 as much as possible incase you already have small cracks which can be from a variety of things, not just heat

 

Blue, no disrespect meant, but many comparisons have been run with both pre and post turbo locations over many miles and conditions and it's been well documented / proven that pre turbo is very accurate and that post turbo most definitely shows a lower temperature (by somewhere in between 150 - 300 degrees) and that is also a bit slower on response. I suppose you could lower your redline to 900 - 1000 but why chance it, it's a 30 - 45 minute job at most to install...

 

Since the manifold is pre turbo, I would think that drilling or tapping with the engine running might increase the chance that shavings could be blown into the turbo instead of out the hole! I wouldn't try it. Another thing to do is using grease on the drill bit and tap to hold the shavings.