hotparts

Hi guys,

after my LS2 with over 1000 rwhp we`d like to build a blown LS7 stable for the german autobahn and race tracks so not compareable with an engine that is only used for some quater miles and daily driving.

Is it right that it is better not to go over 700-800 rwhp to get no problems with the LS7?

Thank you

VERTC6

iTrader: (1)

The LS7 can take a lot, you just have to take out the exhaust valve and install inconel. I have seen Over 800rwhp on the stock bottom end, I wouldnt go more than that without forged pistons.

djfury05

iTrader: (30)

I wouldn't push it that hard without sleeving the block

litle88

iTrader: (20)

Not blown, IMHO I'd get an Ls2 and resleaved it for 427 duty with a good piston and rods. The ls7 runs too DAMn hot and walls are too thin.

hotparts

@litle88

so what would you say for a blown LS7 with better pistons, rods,..

About 700-750 to be save at the track and the german autobahn?

djfury05

iTrader: (30)

Do your research on the motor. It is not the rotating internals that are the weak parts. It is the block's cylinder walls. Too weak at the top. That's why I said sleeve the block.

hotparts

ok, i understand!
With the stock sleeves what would you say, how much power maximum with a blown engine?

stevieturbo

If your LS2 made 1000, what are you trying to achieve with an LS7 ? You would never be able to hold a true 1000rwhp car on any road for more than 30-40secs at WOT as you'd be doing well over 200mph.

As for re-sleeving, I wouldnt trust a re-sleeved block.

Stick with an LS2 or LS3 block, keep bore size small to leave thick cylinder walls and it will be a very sturdy platform.

sandragnx

iTrader: (82)

FYI.Have seen how thin and uneven the stock sleeve are on a LS3 block are?

Im running a sleeved superdeck block from erl with 4.185 bore and 4.125 stroke in my sandrail with a small cam and LS7 heads worked over by Richard at Westcoast and im very happy so far.

litle88

iTrader: (20)

When I bought my factory Ls3 stroker that was built by another vendor here I dropped it off at AES to reassemble it because the motor had switched hands twice but was still new and never ran. So I didn't want to leave anything to chance just in case someone had pulled a cap off or whatever. When they measures the bores it turned out they were tapered from the bottom and they needed to hone it to a 4.0705 bore.

Sales@Tick

iTrader: (3)

This x100.

We've ran plenty of sleeved blocks HARD in our shop cars without a single problem that I know of. How can you say you won't trust one if you've never used one done by a knowledgeable machinist like the guys that have done ours(non-sponsor)?

You can also run a LS2 with a slight .010-.020 re-hone and a 4" crank. You really don't need a lot of cubic inches with boost to make great power.

Just use the right induction/valve-train and power adder and the power will make itself.

hotparts

@stevieturbo

At the german highway you can, absolute no problem there is no speed limit! Also at the racetracks here are many ones with long WOT sections.

stevieturbo

I know there is no speed limit. I also know the dangers involved of doing such things on a public road.

Just because you can do it doesnt mean it is sensible or safe.

A quick blast to a top speed is not the same as trying to maintain that speed for a period of time. Few tyres are rated for sustained high speeds, and a cars aerodynamics will be even more critical trying to maintain speeds.

A racetrack with a long WOT section ? Show me a racetrack where a 1000bhp car can maintain WOT for more than a few seconds when travelling at 200+, given that at only 180mph you are already travelling at 3 miles per minute. ie 1 mile every 20 seconds.

The only racetrack if you can still call it that where you could do that would be the Nurburgring which has one long straight and has a high entry speed to start with

Although it sounds like the OP just wants to maintain WOT for extended periods, rather than actually accelerate fast and achieve a high top speed ?

Sales@Tick

iTrader: (3)

To also sustain those types of RPM needed to make that power at that length of time the camshaft profile will need to mild enough (lobe wise) to not throw everything into a tizzy with valve float. It will be similar to a Nextel/NWS/Busch/Craftsman truck series set-up as they need to turn 8000-9500rpm for hundreds of miles at a time and need to make great power while not wearing out springs which can happen easily in that long amount of time so they use lobe profiles that are mild enough to support this style of racing.

CAMSTER

iTrader: (10)

I say with stock block 550 whp is as much as i would venture and that require to change the exhaust valves for sure.
A lot of people have made a lot of power with stock LS7 but they never come back to say what happened 2 weeks later.

hotparts

@stevieturbo

It doesn`t depend on how long you stay at 100% TPS, it depends on how agressive you drive. On the german highways it is no problem to ruin a car with a higher powered blower kit from the states.

And it also doesn`t depend on how long you stay at WOT. When you stay on for 10-20 seconds than you brake then again and so on, you have extreme forces on the motor and therefore the most kits are not made for.

I have the 4th configuration and now my motor is durable.

stevieturbo

It very much depends how long you stay at WOT for. With that amount of power you'll either end up hitting the rev limiter or doing say 250mph if gearing permits.
With that sort of power it would only take 25secs or so to hit 200 from standstill, so if you're already travelling at 100mph before you go WOT, it will only take say another 10-15 seconds at WOT to be achieving such speeds.
So could you do it for 30 seconds without hitting the rev limiter or hitting ridiculous speeds ? I think it unlikely.

The most important things will be charge cooling, piston cooling and head gasket sealing ( water cooling is obvious ) and ensuring you do not hit or sit on the rev limiter.
And of course as Martin suggested, depending on rpm's used camshaft profile.

mark21742

Just some useless info

The Narḍ Ring (Pista di prova di Narḍ della Fiat, built in 1975), gps location 40.326655, 17.827721, is a high speed test track located at more than 20 kilometres (12 mi) north-west of the town of Narḍ, Italy, in the southern region of Apulia, in the province of Lecce. The track is 12.5 kilometres (7.8 mi) long and is round, has four lanes for cars and motorcycles totaling 16 metres (52 ft) in width and has a separate inner ring for trucks at a width of 9 metres (30 ft). In the cars/motorcycle ring the lanes are banked at such a degree that a driver in the outer most lane need not turn the wheel while driving at speeds of up to 240 km/h (149 mph). In essence, at the so called neutral speed which is different for the four lanes, one can drive as if in a straight lane. However extremely fast cars still require the steering wheel to be turned when going faster than the maximum neutral speed

hotparts

...not only in Nardo, also in Pappenburg Germany.
Here a corvette from a friend with nearly 400 km/h:

jimbos'ss

iTrader: (6)

The autobahn is about as safe as it gets for extended high speed runs on public roads. The turns are banked correctly, the roads are smooth(they use a multi layer system), and the laws are designed to allow for faster traffic. Your definition of safe is relative, and likely based on what you've experienced with roads and traffic laws where your from.
Also there are multiple high speed test tracks here in europe as shown in the videos above.