Hi guys,
I don't know if anyone of you may be interested, or if you guys even know, but I figured, let me share it, since I'm interested:
I spoke to the people at K1 Technologies regarding the crankshaft.
They told me they can make a forged 4340 crank for the LNF, rated to 1000 hp, for about $ 1400. The same is if someone wants to stroke the LNF with the 2.4 LE5 crank (same price, same material). They require a minimum of 3 cranks purchased for either LNF or LE5. Also, if we get a crank/rods combo for either LNF or LE5, the total price will be under 2k.
Since I would be interested in the next few months, I was wondering if at least a couple of you guys may be interested as well.

Thanks
Christian

 

I think the stock crank is pretty stout in this car unless your going for absolutely huge power.

 

Well, I really have 2 reasons for wanting to do it:
1. I would like to stroke it (and K1 sells the forged 4340 LE5 crank and rods to stroke the LNF for less than 2k).
2. (and most important) My Cobalt SS #2 (which is the one that is been currently modded by Nick at BYT) is paid in full, which means i can take it out of the country with no problem, and I'm planning on bringing it with me to Italy for the summer, we do races of 60-70 laps for the 2.0 turbo category cars, which means about 1.5 hours of constantly pushing the car, and I would like to have the most reliable engine possible. Doing that with the stock crank, It scares me a little, even because if I brake it, there is no way I can find a new crank for our car in Italy the next day.

 

You realize that the factory crank in an LNF is already forged steel, yes?

If you're going to break anything in 2 hours of racing it WON'T be the crank.

 

Yes I know the stock LNF crank is forged steel, but somebody before said that it is rated to 500hp. Is it the truth? K1 told me their crank is rated to 1000 hp
On the LNF turbocharged general page, I opened a thread called "stock crankshaft", and somebody there wrote that the stock LNF crank is rated 500 hp. Is it true?

 

**** no, why are you believing everything you read? The crank is the last part in the engine that will fail. Have you ever seen a forged crank fail in an engine?

 

As someone else mentioned in that thread... don't believe everything you read on the internet.

ZZP however is running 500+ HP on a stock LNF crank with no problems last I heard. 500 HP sounds like a really conservative rating on a forged steel crankshaft.

That said... my opinion from seeing what fails most often on A-bodies... I'd say invest in suspension bushings, engine/trans mounts, intercooler + piping. $2k on a crank is throwing money away when there are alot of different areas that could stand to be improved.

 

ya i havent seen any hp rating for the stock crank but ryan at ZZP produced 600+ whp on their stock LSJ crank with no problems that i heard of.

as far as i know the LSJ and the LNF have the same crank... correct me if im wrong

 

I have heard that this crank will hold at least 800hp. If your going to do a crank that will hold 1000hp than you shouldn't be using k1 rods which will give before the stock crank will. In your 1.5 hour races I would be more worried about the block, I would call up bates and see what he will do for a nice set up.

 

LNF crankshaft is forged is forged steel, where the 2.4L is cast nodular iron.

LNF crankshaft is very STRONG and as the other forum member already mentioned, ZZP made more than 600hp w/o any issues.

K1 rods for the LNF is forged.


Unless I want to go 1000hp, I will personally not spend $1400 for an upgraded crankshaft.....since I have to worry about the stock drivetrain being able to hold higher whp/tq numbers FIRST.

 

But if you want to stroke it, is it recommended to use a cast iron crank?

 

with that stroker plan ......you will have a lower RPM range

the cast iron crank will be fine.....for your power goals

 

What do you mean? What's the max RPM range I can get? What's the max power I can get with the stroker?

 

GM says in their ecotec bible, that at 500hp you should upgrade to steel crank, and their chart goes up to 1400hp..... soooo id say the lnf is pretty stout

 

and... i just noticed we can get carbon fiber front clips from roush! come on powerball!

 

I would rate K1 rods and the factory LE5 crank to a similar power level. I'd go that route if you are building a stroker LNF.

 

^this

My cast nodular iron crank supports 800whp (assuming there isnt a belt driven compressor to factor in), and its also a factory GM piece. I doubt it's built much stronger than the ecotec cranks, and even if so, you wont be pushing 950bhp anyway

 

So that's the best suggestion? LE5 factory crank, k1 rods and wiseco pistons?

 

The bes suggestion is to not stroke the motor... Dude you are taking away the beauty of a high revving 4 cylinder. Make good use of the larger turbo nick is putting on there for you by keeping that motor humming above 5,000 RPM, then change your oil after every race since you will be running some serious exhaust temps through that turbo. If you don't already have a pyrometer, I would say get one. 2K on a crank is rediculous when the LNF has a beastly lower end anyways. If you are going to do anything to the internals to increase displacement, why not just punch out the cylinders a bit.

 

^sleeving costs a tad more than a new crank. IMO do both...

 

True, but at the point he is at a stroker motor wouldn't really help on a track that much. The motor wouldn't want to rev as fast since the pistons have to travel farther. If you bore it out it would broaden the powerband. I say leave the internals stock.

 

Whats the deal with the LE5 redline being higher than the 2.2 and 2.0 stock then if it has a longer stroke?

 

Thanks ;-) very good

 

it will still rev fine... the added torque will more than compensate for the slight increase in inertia

 

Yes i think i will. Trying to look for the best way to spend the money, because even sleeves, pistons and rods are a lot, so i was thinking, minus as well..... Yes I got the pyrometer