Advice needed on LQ9 swap for LS1

[wormus]

Hi

I have TVS2300 supercharger, that until recently was bolted to my built LS1. It was running fine until the block split and lost oil pressure. It was making about 850HP/850 LBS at the wheels which, with a flat torque curve proved to much for the alloy block.

I want to keep that power level so am getting everything built into an LQ9 iron block. Standard bore size but stroked to 408ci.

Will this block be significantly stronger than an LS1/LS2 and is there anything I need to look out for?

Thanks.

[Hi-Po]

Hi

I have TVS2300 supercharger, that until recently was bolted to my built LS1. It was running fine until the block split and lost oil pressure. It was making about 850HP/850 LBS at the wheels which, with a flat torque curve proved to much for the alloy block.

I want to keep that power level so am getting everything built into an LQ9 iron block. Standard bore size but stroked to 408ci.

Will this block be significantly stronger than an LS1/LS2 and is there anything I need to look out for?

Thanks.

Your ran 850/850 RWHP on a stockLS1 shortblock?

Your not gonna keep a stock bore size with a 408CI. Thats .030" over.

[wormus]

Your ran 850/850 RWHP on a stockLS1 shortblock?

Your not gonna keep a stock bore size with a 408CI. Thats .030" over.

Forged crank, rods, pistons and ARP studs so not standard. Even though it was bolted together correctly the block still flexed and cracked through one of the oil galleries.

Same question - will the LQ9 be ok with this and is there anything specific to look out for?

[c5z28]

Damn, the lq9 will be good, why not the 402? I am sure I don't have to tell you to get forged

[wormus]

My mistake, standard bore size so it will end up 402 with my stroker crank. All existing parts will be transferred to new block, including CNC 243 heads, Callies/Compstar rotating assembly and new Mahle pistons to fit the different bore size.

I have no idea how resistant the iron block is to flex compared to the alloy ones. Does anybody know?

[Hi-Po]

Forged crank, rods, pistons and ARP studs so not standard. Even though it was bolted together correctly the block still flexed and cracked through one of the oil galleries.

Same question - will the LQ9 be ok with this and is there anything specific to look out for?

Sorry, I wasnt paying attention at all last night. Missed that part.

402 would get it done and leave some meat for a clean up, your not going to break an iron block.

[squirlnutz]

My mistake, standard bore size so it will end up 402 with my stroker crank. All existing parts will be transferred to new block, including CNC 243 heads, Callies/Compstar rotating assembly and new Mahle pistons to fit the different bore size.

I have no idea how resistant the iron block is to flex compared to the alloy ones. Does anybody know?

The LQ4/LQ9 is a much better and stronger block design than the 5.7. The LQ9/LQ4 are the same.The LQ4 is aluminum, LQ9 is iron. They used the same mold for both blocks. The LQ9 is stronger because its iron. Some make a 1000+ RWHP with these blocks in boosted applications like yours

[Hi-Po]

The LQ4/LQ9 is a much better and stronger block design than the 5.7. The LQ9/LQ4 are the same.The LQ4 is aluminum, LQ9 is iron. They used the same mold for both blocks. The LQ9 is stronger because its iron. Some make a 1000+ RWHP with these blocks in boosted applications like yours

LQ4 is iron not aluminum.

LQ4/LQ9 are both iron blocks.

[Firebirdjones]

LQ4 is iron not aluminum.

LQ4/LQ9 are both iron blocks.

Correctomundo

The cast iron LQ block is definately a better choice for the power you are making, but not sure what the limit is. If you find the limit it might be time to step up to a new cast LSx block. But it's 3 times the price.

Another option that we did often when building high HP old school stuff was to hardblock it for more strength.
I'm not that familiar with the stock cast iron LS blocks and how the coolant passages work within and around the cylinders so don't really know if that's an option, just throwing it out there.

[shady milkman]

LQ4 is iron not aluminum.

LQ4/LQ9 are both iron blocks.

must have got the heads going from aluminum to iron mixed up with blocks.

[wormus]

cheers guys, I'm surprised so little information is available on these blocks. There are a lot of people telling me 1000hp is possible on an alloy block but most of them are running cenrti-blowers or turbos, both of which have more forgiving torque curves.

I was surprised how easily the TVS blower broke mine but I'm making about 970lbs at the flywheel from 2500rpm all the way up to nearly 6000rpm.

There are hardly any tales of people flexing blocks to the point where they break. Alloy or Iron.

Also, do CNC 243 heads work well on the LQ9 ? I'm planning on 15lbs boost.

[shady milkman]

Correctomundo

The cast iron LQ block is definately a better choice for the power you are making, but not sure what the limit is. If you find the limit it might be time to step up to a new cast LSx block. But it's 3 times the price.

Another option that we did often when building high HP old school stuff was to hardblock it for more strength.
I'm not that familiar with the stock cast iron LS blocks and how the coolant passages work within and around the cylinders so don't really know if that's an option, just throwing it out there.

call me crazy, but wouldn't a ls2 be fine for his app. that block is a Gen IV and has been shown to handle 1000 fly fine.

just seems like it is a win win with the ls2, you dont get the weight penalty and you get the strength of a iron block (within most people's app)

[shady milkman]

cheers guys, I'm surprised so little information is available on these blocks. There are a lot of people telling me 1000hp is possible on an alloy block but most of them are running cenrti-blowers or turbos, both of which have more forgiving torque curves.

I was surprised how easily the TVS blower broke mine but I'm making about 970lbs at the flywheel from 2500rpm all the way up to nearly 6000rpm.

There are hardly any tales of people flexing blocks to the point where they break. Alloy or Iron.

Also, do CNC 243 heads work well on the LQ9 ? I'm planning on 15lbs boost.

that is true..i have never heard of people flexing blocks..so congrads on having a beast of a set up. Imho the 243s might be holding you back. a nice set of AFRs that are made for the 4.X bore will benefit you. Also with what you are running i would think you should look into the 6 bolt heads/block combo for that extra clamping power

[Firebirdjones]

that is true..i have never heard of people flexing blocks..so congrads on having a beast of a set up. Imho the 243s might be holding you back. a nice set of AFRs that are made for the 4.X bore will benefit you. Also with what you are running i would think you should look into the 6 bolt heads for that extra clamping power

I agree on the 243's, for a large cube motor and forced induction I'd jump to something better.

As for the extra head bolts,,,,,,I am thinking that's only available on the aftermarket LSx blocks. Factory production blocks don't offer that if memory serves.

[shady milkman]

I agree on the 243's, for a large cube motor and forced induction I'd jump to something better.

As for the extra head bolts,,,,,,I am thinking that's only available on the aftermarket LSx blocks. Factory production blocks don't offer that if memory serves.

yes you are right, i supose it depends on how much money the OP is willing to spend ..if i was pushing huge numbers..i would start to look into the lsx block ...expensive yes..but damn it is a solid block. and supports the 6th head bolt.......let me reword my last post to not confuse people

[Firebirdjones]

call me crazy, but wouldn't a ls2 be fine for his app. that block is a Gen IV and has been shown to handle 1000 fly fine.

just seems like it is a win win with the ls2, you dont get the weight penalty and you get the strength of a iron block (within most people's app)

I couldn't answer that honestly Shady. I don't really know if the LS2 block is all that much stronger than an LS1 block. I'm sure design changes were made, but to what extent?? I just haven't heard of many people pushing the blocks to the limits, LS1 or LS2
One reason I mentioned filling with hardblock. We used it on any stock block that was pushing the limits to save a little money. Filling just to the bottom of the freeze plugs. Helped to strengthen the block and keep cylinders from distorting under heavy loads. But I've never heard of using it on an LS motor, and not even sure if the design makes it worthwhile.

If it were my money, I'd go cast iron with that kind of power level. Stock block is only a 70 lbs. weight penalty, a small price for more durability. Aftermarket cast iron blocks are a bit heavier yet.

[Firebirdjones]

yes you are right, i supose it depends on how much money the OP is willing to spend ..if i was pushing huge numbers..i would start to look into the lsx block ...expensive yes..but damn it is a solid block. and supports the 6th head bolt.......let me reword my last post to not confuse people

My thoughts too Shady. That kind of power I'd shoot straight for the aftermarket block, trade the weight penalty for a little more durability.

[shady milkman]

I couldn't answer that honestly Shady. I don't really know if the LS2 block is all that much stronger than an LS1 block. I'm sure design changes were made, but to what extent?? I just haven't heard of many people pushing the blocks to the limits, LS1 or LS2
One reason I mentioned filling with hardblock. We used it on any stock block that was pushing the limits to save a little money. Filling just to the bottom of the freeze plugs. Helped to strengthen the block and keep cylinders from distorting under heavy loads. But I've never heard of using it on an LS motor, and not even sure if the design makes it worthwhile.

If it were my money, I'd go cast iron with that kind of power level. Stock block is only a 70 lbs. weight penalty, a small price for more durability. Aftermarket cast iron blocks are a bit heavier yet.

true. i know that they have been refining the molding process etc and the material that make them very strong..even compared to the ls1. oh well i think i am just a gen IV junkie ls2 or ls3 etc

[Firebirdjones]

true. i know that they have been refining the molding process etc and the material that make them very strong..even compared to the ls1. oh well i think i am just a gen IV junkie ls2 or ls3 etc

Nothing wrong with that

[Hi-Po]

There are a few companies out making LS2 6 bolt blocks. Running deep into the single digits as well. An aluminum block shouldn't be taken out of the running for big power. This engine should see upwards to 2000 HP when its done

6 Bolt LS2