Why do we not see many large displacement FI engines?

[Fiftydriver]

I have always wondered on this. ITs pretty easy to make a +460 CI engine using the LXS blocks. They are certainly strong enough to open up this big and some even up to 500 CI with the tall deck version.

Why is it that we do not see any large displacement engines used with a blower setup up for even mild boost?

I would think a 460-480 CI engine with 6-7 lbs of boost would be scary powerful.

Do we not have any blowers that can keep up with the volumn needed for this size of displacement.

Just curious why its not done. I was reading up about an LSX build that was 500 CI that produced 717 HP and around 650 Ft/LBs of torque and thought, wonder what 6 lbs of boost would do to those numbers.

Certainly am not an expert, maybe there is a very important reason why we do not see this from a mechanical set up reasoning. Just curious and would like to be educated by those that know.

[camarostar2010]

I am no expert but bigger engines usually seem to rev less on the rpm band. I mean as in less total rpm capability in general. So it a trade off mostly. They give more torque but rev a lots less. Plus the long stroke put stress on the block and the sides of the pistons. again this is what I have seen written on some similar articles.

[Padre]

I'm guessing mainly longer stroke is unfriendly, especially because of the compromises you have to make with the pistons on such builds.

Also, as you say, the extra volume would require a bigger blower, which makes it difficult for the guys going the upgrade route. For me, going from a D1 to an F1(n) would require all new pipes (bigger diameter), etc.

E.g. in my build, if I went forged but stock CID, I would be pushing close to 15lbs through my D1SC and making over 800rwhp - through stock heads, stock intake manifold, stock TB, and shorty headers!

Why do I need to go bigger again?

Now, if I started from scratch, 427 with an F1X and all supporting mods would be the way to go, but right now I don't need a freight train.

Padre

[Synner]

It's a recession?

Easy enough to run out of traction on stock cubes so going huge is just added money. Only good if you want a dyno queen, bragging rights, or do lots of sheetmetal work to get huge tires. If I had the cash for 500 cubes I'd leave it all motor.

[8cd03gro]

The longer the stroke and wider the bore, the less friendly to high cylinder pressures.

[LSX-80MM]

All the above, plus a 500 inch motor would be a pig on fuel,I like the fact of making plenty of "USABLE" power,and getting 20+ mpg............

[thebeast916]

Originally Posted by LSX-80MM

All the above, plus a 500 inch motor would be a pig on fuel,I like the fact of making plenty of "USABLE" power,and getting 20+ mpg............

Agreed on that. I'm a 6.0 362ci on 9.5 lbs making a lot of power and still getting 16 city 25 highway.

[speedster]

We actually started with a 454, then 440, 427, 416, 408 and settled on 388. With the large bore and short stroke it is very strong, loves pressure, gets really good mileage and has a boost range upwards of 40 psi. Drives like a little old lady car if you keep your foot out of it.

A while back it took a stout 540 with an F-2 to make similar power and it really chews through fuel.

[Hendrix-Engineering]

Originally Posted by speedster

We actually started with a 454, then 440, 427, 416, 408 and settled on 388. With the large bore and short stroke it is very strong, loves pressure, gets really good mileage and has a boost range upwards of 40 psi. Drives like a little old lady car if you keep your foot out of it.

A while back it took a stout 540 with an F-2 to make similar power and it really chews through fuel.

Wise choice ,when will it be on the track?

[Fiftydriver]

Originally Posted by camarostar2010

I am no expert but bigger engines usually seem to rev less on the rpm band. I mean as in less total rpm capability in general. So it a trade off mostly. They give more torque but rev a lots less. Plus the long stroke put stress on the block and the sides of the pistons. again this is what I have seen written on some similar articles.

The Maggie and Whipple do their best work at low RPM.....

I can see the added stress on the pistons but I thought the LSX and RHS blocks were designed specifically for long strokes and full piston support?

[RSBAD454]

Here you go, 509 CI with Procharger.

[Fiftydriver]

Originally Posted by Synner

It's a recession?

Easy enough to run out of traction on stock cubes so going huge is just added money. Only good if you want a dyno queen, bragging rights, or do lots of sheetmetal work to get huge tires. If I had the cash for 500 cubes I'd leave it all motor.

There are 500 camaros here on Camaro5 that fit that discription Not that that makes them any less impressive, just saying. Lots of our cars are project cars.

With the cash some guys are putting into their cars today, I hardly think we do not see these set ups because of financial reasons but I can understand the mechanical stand point.

[Fiftydriver]

Originally Posted by thebeast916

Agreed on that. I'm a 6.0 362ci on 9.5 lbs making a lot of power and still getting 16 city 25 highway.

I agree that its much more practical to stay smaller in cubes but I think we would all agree that some just want to be way outside the box!!! Just wondering why we do not see more of this, even extreme displacement NA engines are not all that common.

Again, I know we make smaller displacement engines make huge power, just surpised we do not see some of those extreme guys doing something with wild cubes.

Just comes down to not being practical or reliable or it likely would be more common.

[Fiftydriver]

Originally Posted by speedster

We actually started with a 454, then 440, 427, 416, 408 and settled on 388. With the large bore and short stroke it is very strong, loves pressure, gets really good mileage and has a boost range upwards of 40 psi. Drives like a little old lady car if you keep your foot out of it.

A while back it took a stout 540 with an F-2 to make similar power and it really chews through fuel.

So you started with a 454 and simply shortened the stroke to end up with a 388? Interesting!!! I have always wondered, for example, would a 388 combo with long stroke, small bore produce the same HP/Torque as a 388 combo with short stroke, large bore?????

I would think your set up would rev like wild and be hell for stout!!!

[BLACK10]

Big cubes and fi tend to have high coolant temps

[Fiftydriver]

Originally Posted by RSBAD454

Here you go, 509 CI with Procharger.

that car is ugly as a mud duck but damn fast!!!

[RSBAD454]

Originally Posted by Fiftydriver

that car is ugly as a mud duck but damn fast!!!

Matter of opinion, I like it.

[jrpxxii]

The one thing I learned is that by going with an LSX427 and using an F1R that there was too much motor for the blower thus making the blower spin at max rpm and not producing enough boost. Since I decided to stay with my LSX427 I am now going with a larger blower to match the motor more efficiently. If I had to do it over I would follow Bruces route as its much easier to squeeze out higher boost.

[Fiftydriver]

Originally Posted by RSBAD454

Matter of opinion, I like it.

Tell you what, it looks alot better after you see it run the 1/4 mile then it looks before you see it run

[Fiftydriver]

Originally Posted by BLACK10

Big cubes and fi tend to have high coolant temps

That would make sense......

Starting to look like there are just easier ways to make big power is the reason.

[Fiftydriver]

Originally Posted by jrpxxii

The one thing I learned is that by going with an LSX427 and using an F1R that there was too much motor for the blower thus making the blower spin at max rpm and not producing enough boost. Since I decided to stay with my LSX427 I am now going with a larger blower to match the motor more efficiently. If I had to do it over I would follow Bruces route as its much easier to squeeze out higher boost.

I would imagine that stepping up in blower size gets MUCH more expensive as well!!! The reasons are becoming clear why big displacements engines are not that common, at least not for FI set ups.

[blackonblacksls]

Bores over 4.155ish and strokes over 4in in a short deck build give up strength in the piston and head gasket sealing.

Go with a tall deck and you got some pretty serious forced induction motors in the 460ish range.

[jay@redline-motorsports]

if you go with a bigger motor then it will make more on motor and not have to spin the blower as hard to make a number, and if you run out of blower thats not a bad problem just go turbo

[speedster]

Originally Posted by Hendrix-Engineering

Wise choice ,when will it be on the track?

Trying to get it back for Pony Wars in May. It's gonna be close. Hope to see you there again. (Saw you at the last one in the fall)

Originally Posted by Fiftydriver

So you started with a 454 and simply shortened the stroke to end up with a 388? Interesting!!! I have always wondered, for example, would a 388 combo with long stroke, small bore produce the same HP/Torque as a 388 combo with short stroke, large bore?????

I would think your set up would rev like wild and be hell for stout!!!

Kind of. We went through a bunch of power curves and simulations. For best overall 'driveability' meaning street manners and good HP, we ended up with the 388. It is basically a 4.125 bore with a stock length stroke, but with pro-mod bottom end parts. If we were shooting for 2,000 - 2,200 HP, it would have been a de-stroked RHS setup that was in the 440-450 ci range. The present shift point is 7200. That is with less cam duration. Open up the cam a little and the shift point climbs quickly but is not so streetable.

Originally Posted by jrpxxii

The one thing I learned is that by going with an LSX427 and using an F1R that there was too much motor for the blower thus making the blower spin at max rpm and not producing enough boost. Since I decided to stay with my LSX427 I am now going with a larger blower to match the motor more efficiently. If I had to do it over I would follow Bruces route as its much easier to squeeze out higher boost.

J is dead on in that the bigger the motor, the bigger the blower. He now has both so LOOK OUT, because the power will be sick. Oh and a little nitrous to boot !

Originally Posted by blackonblacksls

Bores over 4.155ish and strokes over 4in in a short deck build give up strength in the piston and head gasket sealing.

Go with a tall deck and you got some pretty serious forced induction motors in the 460ish range.

Yes, you get a lot of piston speed and sealing gets tougher with the FI.

Originally Posted by jay@redline-motorsports

if you go with a bigger motor then it will make more on motor and not have to spin the blower as hard to make a number, and if you run out of blower thats not a bad problem just go turbo

Big motors with blowers make sick street cars... The torque is usually ridiculous... P.S. PM me sometime Jay, I have a question for you now that RedLine is in Florida. Thx !

[motorhead]

I think the biggest reason is that newer cars fit small motors betters. If you go to the drags, you'll see that people who are running old cars still use big blocks to go fast. Top fuel, funny car, and pro stock still all run big block based motors.

That 64 plymouth in my sig has a 440 that is stroked. Case in point. I would get laughed at if I had a small block in it.