View Poll Results: What C.I. to use with an APS TT kit?
Iron 370
8
47.06%
Iron 408
8
47.06%
Other....explain and give input in a post
1
5.88%
Voters: 17. You may not vote on this poll
iron 370 or iron 408 build for APS TT?
08-05-2009, 11:58 AM
#1
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iron 370 or iron 408 build for APS TT? I picked up a LQ9 long block not long ago bc my cammed stocker is giving me oil problems on the pickup side that i've yet to fully diagnose (last item to check is pickup tube and I'm cutting my losses after..). In the (fairly) near future I will be in the market for an APS twin kit. I don't need the engine to be a huge dyno queen, I just want it to be strong, reliable, and makes good consistent power. I will also be running it NA until the APS kit goes in, so keep this in mind
I'm trying to decide on a forged 370, or a forged 408.
370
i see it revving higher and making more power up top
408
i see having boost lag, not revving high (thus being easier on other engine components), but requiring a metric ton of air to make good power..
***What are the Pros/Cons to the 370 and 408?
Is it worth having the Iron block?
What's the cost differences I'm looking at having a block prepped/machined as opposed to having it prepped and a stroker crank?
With the 370 will it be worth having a forged crank?
Besides the crank, I have no need for input on what internals to use, Vengeance will direct me with that
Yes, I have done a lot of searches and research, but I still haven't seen a good comparison or anything making me lean one way or the other.
TIA
I'm trying to decide on a forged 370, or a forged 408.
370
i see it revving higher and making more power up top
408
i see having boost lag, not revving high (thus being easier on other engine components), but requiring a metric ton of air to make good power..
***What are the Pros/Cons to the 370 and 408?
Is it worth having the Iron block?
What's the cost differences I'm looking at having a block prepped/machined as opposed to having it prepped and a stroker crank?
With the 370 will it be worth having a forged crank?
Besides the crank, I have no need for input on what internals to use, Vengeance will direct me with that
Yes, I have done a lot of searches and research, but I still haven't seen a good comparison or anything making me lean one way or the other.
TIA
08-05-2009, 12:53 PM
#2
I'm not positive about the size turbos that come with the aps kit but i think most guys run them on stock cube motors. To me it seems like the 370 would work but the 408 is so big that i'm not sure if the turbos will be able to feed that motor up top. The bigger motor shouldn't have a problem spooling the turbos though but in the upper rpm's i think the effiecency of the turbos will be surpassed by alot.
Forced Inductions.com has a great graph on turbo effieciency and what size turbo you need depending on engine size.
I know that theres a new turbo upgrade for that kit , but guys that use single turbos use 70's and 76's on stock cubes, and 88's and 91's on the 408. I would check with aps and see what they reccomend as far as cubes but i think that the 370 would be more than enough for that kit and the 408 would be to much.
If you want awesome low end power you could do a 408 with a 78 or 80mm turbo because the 408 would spool that turbo crazy fast, giving you awesome torque and low rpm power, and it would have pretty good top end.
Forced Inductions.com has a great graph on turbo effieciency and what size turbo you need depending on engine size.
I know that theres a new turbo upgrade for that kit , but guys that use single turbos use 70's and 76's on stock cubes, and 88's and 91's on the 408. I would check with aps and see what they reccomend as far as cubes but i think that the 370 would be more than enough for that kit and the 408 would be to much.
If you want awesome low end power you could do a 408 with a 78 or 80mm turbo because the 408 would spool that turbo crazy fast, giving you awesome torque and low rpm power, and it would have pretty good top end.
08-06-2009, 11:29 AM
#5
I would get the 370 and put the money you saved toward getting the better replacement turbos for the APS kit.....................I don't think you are going to see much of a difference between the 370 and 408 when you put the turbo kit on.
Getting the better turbos from LG is going to be a must
Getting the better turbos from LG is going to be a must
08-06-2009, 01:48 PM
#7
I too am debating which direction to take with my LQx turbo build. I plan to start out with a complete 6.0 engine and build it for boost. Since I will be buying new rods and pistons, this would be the best time to add a stroked crank. On the other hand, many people have had good reliability up to 1000 hp with the stock LQ4/9 crankshaft. So we have your debate on ideal stroke for a turbo build.
My opinion is to build as stout a NA engine as possible and thus not have to lean on it with as much boost. I don't have a specific turbo kit in mind, so I will simply buy a turbo to fit the size engine that I end up with. So for me it will come down to budget. Can I afford to buy an aftermarket 4" crank and still stay in budget.
Your decision is similar, but maybe a little more limited since you are set on a off-the-shelf turbo kit. More than likely you will have all the power that you can possibly use with the 370 and the standard APS kit. My vote for your build is to leave it at 370 in^3.
My opinion is to build as stout a NA engine as possible and thus not have to lean on it with as much boost. I don't have a specific turbo kit in mind, so I will simply buy a turbo to fit the size engine that I end up with. So for me it will come down to budget. Can I afford to buy an aftermarket 4" crank and still stay in budget.
Your decision is similar, but maybe a little more limited since you are set on a off-the-shelf turbo kit. More than likely you will have all the power that you can possibly use with the 370 and the standard APS kit. My vote for your build is to leave it at 370 in^3.
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08-06-2009, 08:58 PM
#9
personallly if i was going turbo, I would do a 370 and save the money on the crank becasue FI gets pricey real quick, your probably going to need that $ somewhere else. I would also do a front mount turbo. Twins give you more pimp factor but the damn APS kit already cost big money and then it comes with questionable turbos. So for about 7k you get a turbo kit then another 2 or 3k the LGM turbo upgrade.
I'd go kentucky turbo no air kit for 3700 on a 370. that kit should be able to push a 370 to 800rwhp pretty easy and cheaper than a APS kit. If you want more theres options for bigger turbos. Kentucky turbo also sells whole fuel kits, radiators, distributors relocation kits, and the other things you'll need to do a complete kit for about the same money you can do a APS kit without the fuel system.
The only problem with a front mount is you going to have to mod the radiatior.
I'd go kentucky turbo no air kit for 3700 on a 370. that kit should be able to push a 370 to 800rwhp pretty easy and cheaper than a APS kit. If you want more theres options for bigger turbos. Kentucky turbo also sells whole fuel kits, radiators, distributors relocation kits, and the other things you'll need to do a complete kit for about the same money you can do a APS kit without the fuel system.
The only problem with a front mount is you going to have to mod the radiatior.
