pkincy

iTrader: (1)

OK, OK a little hyperbole in the thread title. But as I sit here watching the Autorotica show with Dennis Gage and Jon Moss going thru GMs special vehicle collection some interesting things seem to come together. They are showing the Tiger Shark concept now. Remember the yellow C5 with the 7.0 Liter supercharged motor making 780 hp at 8.5 lbs of boost. Jon makes some interesting commments.

He describes the SB motor using the C5R heads and block and describes it as an exercise in "pushing the envelope" to see what can be driven on the street. He mentions "exotic materials" in the parts in the motor. Dennis mentions that it has a revlimiter set at 7000 rpm. Jon Moss replies that without the rpm limiter the motor is good to "about 8500 rpm". Well they won't warranty that ever I suspect (until we get 48 volt electrical systems and camless electronically actuated valves) but I am really anxious to see someone with LS7Edit take the rev limiter off their C6 Z06 and put on some mondo springs and see how fast that titanium can spin. What an interesting time for the true gear head.

Perry

Dave F

With the long stroke of the LS7, I doubt they will let it spin anywhere near 8500rpm. In our World Challenge LS6's, I ran it hard to 7500rpm, but 8500 is fast in a slug of this size

james562

iTrader: (35)

sounds a little high to me

Mike98WS6

iTrader: (5)

I can see maybe 7,500. Even that would be stretching it.

J-Rod

My understanding is that the engineering of the motor is such that it COULD go that high, but will pass GM durability tests @ 7000 safely. That means a pretty fair margin of safety...

BadAndy

I gues we'll find out after the first few 3rd to 2nd mis-shifts

Juiced

iTrader: (2)

I've done that before..... Happy to say my motor lived

Gloveperson

iTrader: (9)

I think 8500 would be pushing it as well. 8000 is as high as I would think it could go, even with some superman like springs.

BiggerJ

Why is that? NASCAR revs to 9000-9500 using similar(if not inferior) parts. The aluminum pistons and titanium connecting rods keep the bob weight in check. The only other places to reduce weight/inertia would be the rockers, pushrods, and lifters. Don't know how much could be saved there?

Gloveperson

iTrader: (9)

Nascar cars get regular maintance and change parts regularly

Stone0fFire

how long do NASCAR engines last?
someone here must know.
i think 800 miles or less.

Louis

iTrader: (7)

Winston cup motors have 3.5" stroke or less. Not 4" like the LS7.

The valvetrain on a cup car is nasty too. Ever seen a welded cam from Comp ( who supplies all but 1 cup team with cams ) Those will run you a grand or more in order to work with the flat tappets.

Comparing apples to oranges IMO. Besides, why would you want to spin an LS7 that high anyway?

BiggerJ

Hopefully you would not be driving your street machine between 5k and 9k all day. I can't see occasional blasts to 8.5k significantly impacting the life of the engine if the parts can handle it.

SmaknaSS

iTrader: (1)

This LS7 sound's like It's gonna be a real street monster.

Bink

I think 7 Grand is amazing for that stroke!! My $0.02.

LPCWS6

Old 4 bolt 454's with factory forged cranks and 7/16 rods are good to 7500 rpm on the bottom end. I don't see a little 8500 rpm action from time to time as that big of deal for the bottom end of this motor but I doubt the valvetrain could handle that kind of rpm's it without some work.

XJGPN

TA Engines typically run around 500 miles before a rebuild. (roughly 2-3 race weekends). I would have to assume due to the big $$$ in Nascar, they wouldn't run more than one race on an engine without a teardown... but that's just a guess.

fastta

NASCAR motors are rebuilt after every single race.

00bluehawk#111

iTrader: (1)

4in===8500 completely doable with the right parts my old drag boat motor .30 454 7200rpm all duy long on a factory crank turned 10-20 --3/8 dimple rods--(the 7/16 rods come apart) and forged pistons. my 540 ci 4.5 bore-4.25 stroke turned 7500 OFF the 500 hp fogger. and this aint no car engine that ever comes off of full load (shifting or rpm drop) i held the 454 and 540 across the lake many times with no problems the 454 lasted 6 summers before it was rebuilt and all it needed was a set of valves and brngs/ rings. btw both were roller motors 454= 650 hp @7000 rpm 540= 850 hp@7300 rpm on a very conservitive dyno (thomas racing eng in cumming ga) he was also the eng machinist.

LOnSLO

iTrader: (15)

Well, I turn my 408 just over 8000. That is no problem at all. Of course I'm using good parts, but nothing exotic.