FI with big cube 440ci
Thread Starter
Instructor
Joined: Jul 2006
Posts: 228
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From: Southern Germany
FI with big cube 440ci
I have a more in general question on FI with big cubes. How come there are not too many big cube engines used in FI ? Wouldn’t a forged 440ci be a great platform to start FI ?
Is this just a money concern or are there really downsides to supercharging a big displacement engine like for example a 440ci block.
Are the heavy pistons of a big cube engine a downside ?
Let say I want about 730rwhp,… I imagine that with reaching this number my current 348ci would have a lot more stress on the parts than a forged 440ci would have, am I right ?
I’m asking since I’ve been offered to upgrade to a built forged LS2 based 440ci for a reasonable price. Not sure if it’s worth the hassle though…
Thanks,
Alex
Is this just a money concern or are there really downsides to supercharging a big displacement engine like for example a 440ci block.
Are the heavy pistons of a big cube engine a downside ?
Let say I want about 730rwhp,… I imagine that with reaching this number my current 348ci would have a lot more stress on the parts than a forged 440ci would have, am I right ?
I’m asking since I’ve been offered to upgrade to a built forged LS2 based 440ci for a reasonable price. Not sure if it’s worth the hassle though…
Thanks,
Alex
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Honestly I think the major reason on the C5 platform is cost, first you have to build the big cube engine then you have to pay for the FI.
If you look at the C6 platform they are doing FI on the 427's so MHO that cost is a major factor.
On the other hand there are always some people that just want the biggest baddest SOB out there and don't care what it cost's.
If you look at the C6 platform they are doing FI on the 427's so MHO that cost is a major factor.
On the other hand there are always some people that just want the biggest baddest SOB out there and don't care what it cost's.
Race Director
Joined: Apr 2007
Posts: 18,051
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From: long Island NY
I don't think 730rwhp is very stressful, many guys running 850+ on 346's
I think issues with high cubes as something to do with centri's for instance do better with smaller cubes like 346 or 402's. I think I remember someone writing after a 416 there less efficient. Maybe someone else could chime in.
I think issues with high cubes as something to do with centri's for instance do better with smaller cubes like 346 or 402's. I think I remember someone writing after a 416 there less efficient. Maybe someone else could chime in.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
With the power numbers people are currently getting out of engines of smaller displacement, I can't imagine how many people could actually get more power to the ground if they had it.
I would guess the extra $$ is better spent on drivetrain related components..
I would guess the extra $$ is better spent on drivetrain related components..
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Pro
Joined: Mar 2006
Posts: 501
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From: Mission Viejo Ca
440" from a non-sleeved LS2 block means a 4.1" crank. Your issue will be the fact that you are dropping the piston further out the bottom of an already weak sleeve and have more rod angle/side load on the piston. Better off staying with a 4" stroke 402. Centris in general work well with more bore and shorter stroke which builds boost quicker.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
You have to be careful over stroking an engine for F/I or nitrous. It often times takes the support of the lower rings away due to the wrist pin being pushed up and also puts the rings closer to the flame. A smaller stroke allows you to bring the rings down and have a thicker crown on the piston to keep it out of the fire.
Another problem is there aren't any real easy ways to max out that kind of displacement. You would end up with a F2 or V27 and that's a road less traveled for a reason. One-off builds are usally a PITA and much more expensive.
Another problem is there aren't any real easy ways to max out that kind of displacement. You would end up with a F2 or V27 and that's a road less traveled for a reason. One-off builds are usally a PITA and much more expensive.
Melting Slicks
Joined: Mar 2008
Posts: 2,412
Likes: 4
From: Houston/Dayton Texas
C5r is a great setup.. but its a compete waste unless you use it for what it is instead to be used for... that setup should be of 1000, no questions asked on a very safe tune
Its cost effectiveness and bigger cubes don't preform well with small blowers... anything in the F1 series is small for that size. F2 would do nicely.
Former Vendor
Joined: Jun 2002
Posts: 2,045
Likes: 3
From: Bridgewater Ma
440" from a non-sleeved LS2 block means a 4.1" crank. Your issue will be the fact that you are dropping the piston further out the bottom of an already weak sleeve and have more rod angle/side load on the piston. Better off staying with a 4" stroke 402. Centris in general work well with more bore and shorter stroke which builds boost quicker.
So ,when that is done,yes you can easilly do FI on one.I'd recommend the bigger bloers like YSI or F1 to feed it.
The purpose of the stroker is midrange power/tq. Looking at peak hp is for dyno junkies.A 346 can hit 800hp but a stroker motor will more than likely make alot more power across the curve.We have a stroker 418 that makes 800hp but make 550tq at 2500rpm.
Burning Brakes
Joined: Feb 2002
Posts: 1,154
Likes: 25
From: Jasper GA
C5r is a great setup.. but its a compete waste unless you use it for what it is instead to be used for... that setup should be of 1000, no questions asked on a very safe tune
Thread Starter
Instructor
Joined: Jul 2006
Posts: 228
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From: Southern Germany
The 427 was originally built in 2003 as a NA motor. I went with the $$$ block because of horror stories at the time about Darton sleeves. It was modified for the blower in 2006 (lower C.R. LS7 heads, stronger rods, etc.) after the C6 Z06 arrived and everybody and his dog could have a 427. I may eventually pulley the blower down and add meth, but for the moment, what I have is exciting enough.
What were the horror stories with Darton sleeves ? The engine in question has an LS2 with Darton sleeves (wet ductile iron) Durabond bearings. I don't want to find out the hard way
jobberone
Joined: Aug 2003
Posts: 2,062
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From: Kailua Kona HI
you can get 'cubes' more quickly with boost than with bore and stroke. One poster is right though in that you will gain more low end torque with more cubes. Piston weight is not a major concern unless you're going to rev high.
Thread Starter
Instructor
Joined: Jul 2006
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From: Southern Germany
Is 6600rpm considered high for this size of cubes ?
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
It depends on the reciprocating weight and there are calculations for that, but 6600 shouldn't be a problem, however you will most likely benefit from shifting earlier.
As for Darton Sleeved blocks, If you don't put a wet sleeve in exactly right, you're going to have a large, expensive chunk of worthless aluminum and steel on your hands.
I have heard this mentioned by many respected machine shops such as Erik Koenig, Race Engine Development and our very own Virginia Speed.
As for Darton Sleeved blocks, If you don't put a wet sleeve in exactly right, you're going to have a large, expensive chunk of worthless aluminum and steel on your hands.
I have heard this mentioned by many respected machine shops such as Erik Koenig, Race Engine Development and our very own Virginia Speed.