aluminum vs iron block
08-30-2005, 08:06 AM
#1
aluminum vs iron block I am putting an LQ4/4L80E in my 1985 Jaguar XJ6. The car's original curb weight is about 4,000lbs. The original engine and trans were very heavy, but so is LQ4/4L80E. I am planning a boosted setup looking for between 600 and 700hp.
What I really want is an aluminum LS1 block because of the lighter weight (I think about 65lbs) because my car is already heavy. I'm worried about being able to hook up as well as having a good distribution for a good feel on the road. Do you think this weight savings is justified or should I go with the beefier iron block because of the higher boosted HP and torque and FI setup is going to produce?
What I really want is an aluminum LS1 block because of the lighter weight (I think about 65lbs) because my car is already heavy. I'm worried about being able to hook up as well as having a good distribution for a good feel on the road. Do you think this weight savings is justified or should I go with the beefier iron block because of the higher boosted HP and torque and FI setup is going to produce?
08-30-2005, 12:26 PM
#7
I'm not so much interested in "breaking" an aluminum block... I'm worried about it flexing and causing serious damaging wear on my rotating assembly.
But that even takes a back seat to the beef of my question... I could start my build right now with my iron block... but do you think it's worth the wait to find an aluminum block?!
But that even takes a back seat to the beef of my question... I could start my build right now with my iron block... but do you think it's worth the wait to find an aluminum block?!
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08-30-2005, 01:08 PM
#9
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Honestly FastKat, I think the general consensous around here is that if you are concerned about the weight and at those power levels, then wait and find the alum. block.
08-30-2005, 01:13 PM
#10
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Originally Posted by FastKat
I'm not so much interested in "breaking" an aluminum block... I'm worried about it flexing and causing serious damaging wear on my rotating assembly.
But that even takes a back seat to the beef of my question... I could start my build right now with my iron block... but do you think it's worth the wait to find an aluminum block?!
But that even takes a back seat to the beef of my question... I could start my build right now with my iron block... but do you think it's worth the wait to find an aluminum block?!
I just question the decision by some f-body owners to trash the light gem of a block because the "think they might" need it.
Irreguardess of what is actually known.
Its nothing new in hotrodding though.
08-30-2005, 02:46 PM
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Harlan ran around 1100HP through a aluminum block running 8.2 and hitting high 160's - low 170's in the quarter. I'd say its just preference at your power level.
I personally went with a iron block due to the price.
I personally went with a iron block due to the price.
08-30-2005, 03:25 PM
#13
Originally Posted by Boostaholic
Harlan ran around 1100HP through a aluminum block running 8.2 and hitting high 160's - low 170's in the quarter. I'd say its just preference at your power level.
08-30-2005, 05:43 PM
#16
stock ls1/ls6 block, stock crank, good rods/pistons then balance/blueprint everything. ARP bolts....
For your power levels this should be fine. ProStock John and Harlan are making way more power than you intend to and have had no problems. They are both running stock cranks as well I believe with stock main caps with ARP studs!
Spend the money on a quality intercooler and the right sized injectors, nice exhaust, good tuner for your car.
Here is John's combo:
LS6 intake
stock ported OEM TB
stock crank
eagle 6.125 rods
diamond pistons, for 8.2:1 compression, a little sturdier than the off the shelf 9:1 ones
6.0 heads ported with GM MLS gaskets
Big supercharger.....
BigStuff3 (BS3) $$$
For your power levels this should be fine. ProStock John and Harlan are making way more power than you intend to and have had no problems. They are both running stock cranks as well I believe with stock main caps with ARP studs!
Spend the money on a quality intercooler and the right sized injectors, nice exhaust, good tuner for your car.
Here is John's combo:
LS6 intake
stock ported OEM TB
stock crank
eagle 6.125 rods
diamond pistons, for 8.2:1 compression, a little sturdier than the off the shelf 9:1 ones
6.0 heads ported with GM MLS gaskets
Big supercharger.....
BigStuff3 (BS3) $$$
08-30-2005, 10:52 PM
#18
Originally Posted by mdhmi
I have yet to see a single reason except for price to go with an iron block.
Mark
Mark
An iron block has less flex than an aluminum. Now that doesn't mean that your motor is gonna blow everytime you boost it. It does mean that its gonna move and has much more chance for diaster than an iron. Iron is cheaper, it weighs more, but if you don't mind the weight. Its the way to go for a budget build. I'm gonna run a C5R block on my setup, but its much more money to go that route.
08-31-2005, 06:44 AM
#20
It really is a moot point at the power level that you are wanting to obtain, but the LS2 aluminum block is a little stronger due to the siamiezed cylinder design, where there are no water ports next to the cylinders. You can pick up a new LS2 block for a grand, which also gives you a larger cubic inch engine to start with. Bob