ok so here is what i have. 03 2500hd 8.1l. was stock untill a nice detonation now im building it up but im trying to make sure of just why i had the problem.

whipple w/ 5.5psi(non intercooled), 42lb injectors, westerns tune, 180 thermastat, whipple bs wireing eliminated..

im betting my main problem was tthe non intercooled. i have followed a few forums and i have just now signed up to ask my own questions and hope to get some answers if there are some.

ok new set up that im working on but really dont want to blow.
bored to 4.31 (60 over). front mount air/air intercooler. 42lb injectors. 5.5psi boost. westerns tune. ported/polished heads and intake(marine). stock crank/rods.. COMP Cams 46-422-9...


180 thermastat??? or do i need 160??....
42lb injectors or do i need bigger??
should i do a walbro fuel pump??


all said and done im looking for this to pull my 32ft fifth wheel camper thats 16k loaded. not looking for killer hp just enough for me to feel comfortable towing and have enough *** to get up the road

 

First thing would be to find out why it failed the first time...if its from detonation is probably too much timing, or poor/not enough fuel.

What plugs are you using? Should be using some heat range 7 (BR7EF) given that you were non-intercooled.
Do you know what the injector duty cycle is/was? 42s seem a bit small for that combo.
What fuel pump? If its the stock one you should definately upgrade to something like the aeromotive 340.
I would do the 160tstat.

A little bit of boost on that 8.1 should pull like a pissed off mule.

 

running stock pump, as for the plugs i cant remember what they are they were at the time for being replaced.. fuel i had a half tank of 87 in when i did the install and filled it with 93 then ran to half tank and filled it again, did this twice.
the piston went while in 2nd 3rd gear WOT passing a bike. noticed a loss in power and a check engine light flashing but no code.

im still betting on lean condition did it because i never did check my fuel press so when i get the motor back together will all the new goodies im gonna check it at idle and at Wot. also installing a air/fuel on each side of the exhaust so i can see if i run lean on either.

 

160 thermostat yes
intercooler yes
at least one heat range colder normal spark plugs gapped to .035
not iridum not platinum normal copper core plugs
Always run premium I would upgrade to at least 60 pound injectors
make sure the fuel pump you put in is rated higher then what you already have my 07 fuel pump is 80 gph my 04 pump was 40 gph

My .040 over block seemed to run warmer but not sure because one was stock and one was not.

 

ed thanks for chiming in i was hoping you would, also hoping that tierod and whipple 496 will.

i have a set of 62lb injectors for a ls7 but ill halfto make some adaptors since they are about 1/2 in shorter, or i was thinking of sending my injectors to a shop that can do them out to a 60lb.. thinking walbro 255 inline pump.

 

I replied to your PM....but...

Without seeing a data log its just a guessing game. First impressions are you NEED an intercooler, 60lb injectors, and a fuel boost pump. On my truck I was running 117% duty cycle on my 42lb injectors and stock pump at 6lbs of boost. You may need to dial back your spark advance some too. The 8.1L is very testy when it comes to timing.

With 60lb injectors, Bosch pump, and 6lbs of boost It dropped to a safe 80%-85% IDC.

Non intercooled I was running 220+ degrees air temps at the intake. Adding an intercooler dropped those temps more than 100 degrees.

Good luck.

 

kinda what i was thinking.. i do have a intercooler thats going on with this new motor. also found these guys who can resize these 42lb to 60lb
Stiegemeier Fuel Injector Services

looking at my programer it was showing 15 advanced under full boost.. wondering if thats just way to much. gonna halfto ask westerns to dial it back a little

 

the adpaters may be cheaper and they do sell em, but i think you will need connector adpaters as well. So it is a toss up

 

oh also me making 640 to the wheels I am using 85 pound fast injectors cranked up to 78 psi and I am like at 80 percent duty cycle. Just a thought

 

damn ed not bad.. yea the 62lb ls7 injectors i have are also FAST brand.. i do have a metal lave here so its been kicked back and forth about doing them on it