New idea for an engine

Thank you Tony for that input!
Also Dan for the numbers.

The whole point of my idea was to have an engine making high end power. Obviously I'm sacrificing some torque and low end potential.
Plus, I was thinking about boring out the F54 to increase bore.
It's a high budget buildup to have a high revving L-series. I don't intend to do it anytime soon but seeing that most parts from any L-series is interchangeable I couldn't resist thinking about it.

The V10 F1 engines of the 2004 season have something around a 60mm stroke with over 100mm bore.
There's a reason they idle around 4k rpm and make peak horsepower at around 18k.
The bore and stroke on those tell you why they only have around 250lbs-ft of torque while having close to 1000hp.
They use the best engineers in the world to make an engine to produce the max output with limited cylinder numbers and displacement.

Same with a light F1 car, it doesn't really make sense to have a torquey engine on the lightweight Z. Light cars benefit more from a high revving, high horsepower engine. I'm not criticizing 3.1 stroker owners. It's just that my personal preference is with high revving engines.

There's just one problem...

with the L-Cranks you get into serious harmonics much above 8500, and a stock L28 will rev there just fine with only head work, a cam, and induction to support it.
Our Bonneville car did that.
The 2 liter we are running should go to 9, but we have three spare cranks in expectation of the breakage or crackingthat will inevitably develop when wound that tight...

So it's not like you will be able to rev to 12K or anything likethat, you WILL be below 9K, and you don't need any special destroke job to do that.

The GTU cars that competed in Trans-Am needed an engine below 2.5 L, so the L20A crank and L28 bore gave them the MAXIMUM displacement within the rules allowable overbore for "production" blocks---which is why they used it. In that case, within the structure of the rules, it gave the MOST displacement, and revved high, which you have to do to make power with a small engine. Given their situation, it was a novel approach, and worked well on thetracks they ran on. There was a comparo between the two in Road and Track I believe where they showed the performance differences between the 2.5 and the 2.8 engines in two different racing cars (maybe it was a 2.4...)

>"The whole point of my idea was to have an engine making high end power."

Destroker will lose you high-end power, see above. For the sake of a couple of hundred rpm up top.


>"Plus, I was thinking about boring out the F54 to increase bore."

To make up for the lost displacement. But you're STILL at a displacement deficit compared to what you'd have with the L28 (or LD28) crank.

F1 engine designers have a displacement limit, and a clean sheet of paper (whatever bore x stroke they want). We are for the most part limited to what Nissan made, ultimately. And most of us don't have a displacement limit (and most of us that *do* are still forced to stick with stock or near-stock bore x stroke anyway). Maximum performance for us means maximizing displacement, regardless of what may be perceived as "low-performance" bore/stroke ratios.

>"Light cars benefit more from a high revving, high horsepower engine."

What is a "benefit" depends on what is desired. If low-end torque is desired (street), large displacement fills the bill. If maximum high-rpm power is desired (competition), large displacement fills that bill, too.

I don't see the point to being able to rev 250rpm higher (if that) while GIVING AWAY a measure of peak high-rpm power and even more torque. You're revving *slightly* higher but defeating the goal of maximum performance!

IF you don't care about ultimate performance, and ONLY care about being able to rev a little bit higher, then the destroker makes some sense. But that goal doesn't make any sense to me.

Thanks again for the input Tony!
I forgot that you were running a 2 liter L-series. I guess I got the best answer from the best man.
I would love to read the Road & Track comparo test. Remember which issue it was in?

I guess in an everyday car, a stock L28 with the proper head and intake setup would be enough for 8k.
Actually, anything above 8k in most road cars today seems like you're pushing it.
Maybe I should give Tomei a call and see what they have for L-series engines. Maybe Tony beat me to it and found out they don't have cranks for the L-series. Tomei makes some wonderful things for engines . . .
They also sell full complete race engines too.

For people saying it's not a good idea, why do you say so?
Is it because of everyday practicality issues? Is it because it'll reduce torque output? Is it because it's more complex than just swapping in a normal F54? Is it because you think the L-series is just too old?

****, I've seen KPGC10 Skyline GT-R's with 30 year old S20's revving over 9k without a problem.

Yeah, I should clarify...

The bottom end did indeed use stock crank and rods.
We ran this engine for over four seasons.
WITH PRESSED IN PISTON PINS TO BOOT!

Though free-floaters with teflon buttons would be the way we woudl do it over, and have built the L20A engine.

But yeah, standard Preparation Regimen: polish stress relieve, shot peen ,and balance the **** out of it electronically with the entire rotating assembly there.

We would shift at 8500rpm as our power peak was at 8250rpm.

Though, oddly we found that our fastest times resulted from skippin two gears while running up through thegears, the "close ratio direct-drive tranny was more for road racing, it didn't need to be as closely spaced as the [ismaller displacement engines[/i] apparently!

But yeah, just MAKE SURE YOU HAVE A REAL BALANCER ON IT AND MAKE SURE IT"S PROPERLY INSTALLED! The first crank was wrecked when the balancer vibrated off. We did not have the option of the new BHJ Dampener. I would go with that unit in a heartbeat over the NISMO unit we had used. Big nut, and THICK washer to hold the crank pulley FIRMLY on the snout!

I wish I had more video of the car making passes singing along for almost a mile straight at 8200.....8300....8400.....8500........

Never went "Boom" but after thatfirstseason when the crank pulley got welded to the snout so we could try and finish the season, we rebalanced it, installed a new crank, and ran it for another four seasons!

So "stock" is stock, but with common sense preparation and a good balance job!