Here's the thing about the internet and especially a site like ours....LS7 + E85 + Vortech supercharger will make around 650-700whp safely.
The first 2 pictures are pics I took at Autoclub Speedway. The driver stated his car is/was 100% STOCK. Oil starvation siezed a rod thus air conditioning his block, dumping oil all over his cats, which then caught FIRE underneath and since the car was moving forward, it blew the flames all the way to the back and resulted in the torched rear end you see here. This was not a result of any supercharging.Problem is your world and real world do not agree and has costly end results
Multi LS7s, go boom :drunken:
Again, not wanting to be argumentative, but can't say I agree with your statement.wether its been stated yet or not a Darton sleeved block can be comparable in cylinder strength as an iron block
Hi, guys -
I just acquired an LS7 engine and am using 9.2:1 compression Diamond pistons in the stock bore, and a 4.125 forged crank I had in a 422 Iron block stroker, to create a 441 CID engine to be modestly boosted. (Will see which of my two pullies get me there, but I'm anticipating the ability to run 5-6 PSI or 8-9 PSI .. rough guestimate from what these did on my 422 of 8-9 PSI and 23-13 PSI respectively.)
With a good tune, do you think I'm in safe territory?
I don't have another $3000 to get it re-sleeved and feel I'd be perfectly happy with what a 441 should produice with a modest amount of boost.
There is always going to be a limit to any engine with how much boost it can withstand to hold. Increasing the durability of the rotating assembly allows to increase that limit but the engine itself can only withstand so much cylinder pressure before things exit stage left.
The key ingredient to keeping an LS7 happy with higher boost levels is in the tune. You can rattle an LS7 apart at 10psi if you didn't know what you were doing. With that being said we've pushed a stock sleeved stock LS7 block to 23psi without any damage so asking for it to handle 15psi in your set up is just fine.
At 7.0 liters and 7.5 lbs of boost on our stage 2 engine package utilizing our MTI Racing proprietary cylinder heads and valvetrain, we have acheived over 800 horsepower on a STOCK LS7 in our engine dyno test cell.
The final product is quite amazing. Huge power and tons of torque down low in the rev range where you drive the car. (600 rear wheel torque at 3000rpm and above)
What do these guys know that you and I don't? Are they blowing smoke up my rear?We have run 25 psi of turbocharged boost (1500+ hp and 1500+ lb-ft of torque) with the LS7 block in our customer's standing mile Z06. We also have lots of customers running 10 to 15 psi of boost on turbocharged and supercharged LS7 blocks without any block related problems.
Me too.It would be interesting to find out how many of those aforementioned engines are in one piece after a year of driving them.
While it is true that dished pistons, cc'd heads, even thicker head gaskets will lower the CR of an engine you still have to consider the cylinder walls (even sleeved) on the bl ock itself. The Ls7 engine block is extremely similar to the Ls6 block except the Ls7 is already bored to 427 cubic inch. That means the cylinder walls are already thinned out by GM at the factory. That doesn't make it a brittle engine or unmoddable, but it does make you very leery of how much boost the walls will take.Mike, I appreciate your 'humble' advice.
What I'm having trouble with: all the vendors I talk to say if I get dished pistons designed for boost, make the compression ratio fit a boosted configuration and my internals are forged (as they are), it's all in the tune.
Something to chew on as do shops lie or not when selling high dollar boost installs for stock engine ?Me too.
I'd also like experiences by folk who built a forged low compression engine and share how they burst it.
So far, I'm reading mostly theory and the only people who have practical experience are the vendors who say they make it work or people who tried to boost purely stock LS7's.
Theory and opinion is good ... but, I'm hoping I encounter someone with prior experience.