foryorent

I want to build LS7 based engine using all aftermarket components which will rev to 8,000 rpm. My goal is 650 bhp, as much torque as possible at least 500 ft lbs, and a red line of 8,000 rpm (fuel cut off at 8100). Peak power can be made where ever will provide the broadest power band. I would like to see the hp stay above 500 at 8,000 rpm.

I was thinking of using this block and head from World:
https://ls1tech.com/forums/showpost....6&postcount=37

Unless something better comes out, but this looks pretty nice.

What else do I need to complete the engine and make it reliable with the kind of power output and red line? I was thinking some aftermarket balanced rotating assmebly, aftermarket valve train components, ect. But I do not have much experience with this stuff, so I was hoping you guys might know a bit more. What exactly do I need? How much do the different components I would need cost? Are they avaliable for the LS7 yet? Who makes the best? Who makes what I would need at a good price? Any advice would be appreciated!

Dan

DavidNJ

The answer is yes, but why?

First, 650 crank hp is easily done with a 427 under 7000 rpm.

Second, there is no problem building the mechanical components (some mild tradeoffs), however it will require custom electronics. Expensive to buy and tune.

Using Ti valves, a good shaft rocker system, stiff springs, and a sold roller cam, the valve train can handle 8000.

With the right crank, rods, pistons, and pins the bottom end should handle it.

The question is why?

If you are racing in a displacement limited class and want max hp, then it makes sense. A 427 at 8000 is like a 500 at 7000, if you can maintain the airflow.

If you are going through a torque limited driveline (some mid-engined applicatiion), then you would probably destroke it, so that you made peak power at 7800-8000. where you would only need 450 lbf-ft of torque.

In that case you would also be interested in lightweight rotating assembly in order to reduce inertia losses in the engine during acceleration.

SStrokerAce

iTrader: (2)

I don't see why it would be a issue.... just a 427 drag motor, the parts are out there or they can be made. 650hp would be light IMHO.

Bret

foryorent

why? because 8,000rpm sounds awesome.

AdioSS

iTrader: (2)

build a 9000 RPM 427 LSX? Sure, it's been done

x phantom x

iTrader: (14)

now THAT's a reason, if I've ever seen one ...

foryorent

any one have links to examples of high rpm LSx engines?

I am 99% sure I want to go LS7, but I might have to wait a while for the right parts to come out? Can currently avaliable LSx components work in this type of design?

Redline-Motorsports

iTrader: (3)

If you can make your numbers at a lower operating range...do it! RPMS kill a motor no matter who builds it....meaning in the long run!

The valvetrain will be the limiting factor. Be prepared to drop some mad cash on Titanium everything!

Would be cool to see the tach read 8K+!!!

H8 LUZN

Not exactly.. its the peak velocities and accelerations of the pistons and sliding velocity on the bearings that kills motors.

F1 can spin 20,000 rpm but their piston velocites are around the same as any other racing, i.e. nascar, etc..

For high RPM's, have a shorter stroke and smaller bearing diameters and if you do your homework, you'll be fine

DavidNJ

Actually, bearings get all their where on startup. They run on an oil film otherwise.

F1 cars uses pneumatic valve springs that get charged between sessions and sometimes during sessions. Titanium pieces would reduce their costs. Also their valves are small, as are their cylinders.

Honda and BMW have several cars that run to that rev range. And many Ferraris, etc. do.

All Nascar Cup cars run to 9500-10,000 (except at restrictor plate races.)

With a stiff enough valve spring and a mild enough cam (it has to be a solid cam), you may even get away with a Ferrera hollow core valve.

MrDude_1

iTrader: (4)

their piston velocity's are alot higher.. the FORCE stays low enough for that engine to last JUST long enough... they keep the force lower by keeping the weight low.

THE_SUPRA

i am so lost its not even funney!

Old SStroker

Mr. Dude, H8 LUZN is correct. Average piston velocity is a function of stroke and rpm only. Maximum piston velocity takes into account rod length also. Average piston velocities in 19,000 F1 engines are about 7% LOWER than 9700 rpm Nextel Cup engines. The same applies to maximum piston velocities. Cup engines have strokes around 3.26 inches, and F1 engines have strokes around 1.60-1.63 inches.

Where F1 engines have bigger troubles is the max. piston g-force which is about 10,000 gs. Cup engines are about half of that. Because forces are proportional to mass and acceleration, you are correct that F1 engines keep the forces down by using lighter components. The forces are still extreme however. Imagine a 3.8 inch diameter piston (F1) with a weight less than 1/2 of an already very light 4.18 inch diameter Cup piston.

F1 engines need to run two races which is about 800 km on the engine in anger. Interestingly enough, there are some of the rotating/reciprocating parts that are not ready to self-destruct at that point.

Katech_Jason

iTrader: (19)

SStrokerAce

iTrader: (2)

Oh no not those dam motors....

Katech_Jason

iTrader: (19)

You dont like spinning triangles?

MrDude_1

iTrader: (4)

well, i apologize if im wrong, but the last time i looked at the reported stroke and RPM info, i saw insane piston speeds... i think me being wrong here is more of the case of NASCAR spinning their motors faster then F1 running less piston speed.. lol.


spinning triangles dont like apex seals.

Katech_Jason

iTrader: (19)

Good point
haha

DavidNJ

You can make something strong enough to go 100,000 rpm. However, there is a trade-off between strength and weight. Both NASCAR and F1 run as close to the limit as they can...with rods, pins, pistons, valves, etc.

F1 engines lose a bit to the 2 race rule. In the last race Raikkonen was in the second race of a two-race engine, Alonso had a new one-race special. And he walked away.

8000rpm makes sense when you can make more power up there. You will be hard pressed to find a head, intake, exhaust, and chassis that will let a 427-500 cid LSx breath up there. I was thinking about it once, however that was going to be a 325-350 cid engine with limited torque to fit within the drivelines restrictions.

Forced induction will allow an engine to live up there. Supra's run to 10,000 to make power, with really short rods. However then you are looking at a 1,000+hp, $40-50k motor with another $20k or so in the driveline.

Are you sure you wouldn't prefer a Ferrari instead?

foryorent

Katech,

Are you guys working on a rotor project? I personally love them. A 3 rotor turbo in a Ultima would be pretty tough to beat. They are so light, and make so much power for there size. The 3 rotor is something like 2 liters and you can make insane amounts of power with it.