LT1 Boost, need info guys
11-25-2008, 09:38 AM
#1
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LT1 Boost, need info guys
OK, so I have made a post about this about every year, trying to get as much info as I can. Well the time has come that I have FINALLY made a decision and am going to go through with it. I am taking my block to the machinist this weekend when I am home for Thanksgiving. But I had a few questions first.
I plan on doing a Splayed 4 bolt main and then also filling the internals with Callies Compstar Products. But, I don't know what pistons to go with. I want somewhere around a 8.5-9 CR. The kit I am thinking about buying is already set up for 12 PSI, and I would like to start out with that after the block is built.
I already have LE2 heads, LE2.2 cam and LE Intake. But right now I don't know to either go with a 355 or a 383.
Basically guys, I just want to know which route would have the most drivability and make the most power. Either a 355 or a 383, and which heads to go with?
I plan on doing a Splayed 4 bolt main and then also filling the internals with Callies Compstar Products. But, I don't know what pistons to go with. I want somewhere around a 8.5-9 CR. The kit I am thinking about buying is already set up for 12 PSI, and I would like to start out with that after the block is built.
I already have LE2 heads, LE2.2 cam and LE Intake. But right now I don't know to either go with a 355 or a 383.
Basically guys, I just want to know which route would have the most drivability and make the most power. Either a 355 or a 383, and which heads to go with?
11-25-2008, 09:56 AM
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Given all other variables are the same, I would think the 383 would have more power and be more street friendly because of the increase in cubes and better bore/stroke ratio. I would look at changing cams too. If you are going FI, might as well get a cam that is made more for the blower.
11-25-2008, 05:45 PM
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what size turbo are you using?
Definately need more details on the kit.
If it is a t76, s400, gt-88, anything along those sorts a 383 would be fine
If its a t70, t67-1, t76 a 355 will be fine
A 355 is at the lower limits of the t76 capability while a 383 is at the upper limits IMO
I would look at either diamond, je, or mahle pistons too
Definately need more details on the kit.
If it is a t76, s400, gt-88, anything along those sorts a 383 would be fine
If its a t70, t67-1, t76 a 355 will be fine
A 355 is at the lower limits of the t76 capability while a 383 is at the upper limits IMO
I would look at either diamond, je, or mahle pistons too
11-25-2008, 06:04 PM
#5
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Pistons: Diamond, JE, Ross. Something good.
Heads: if you already have le2's you should be good there. But sending them back to be le3's would even be better.
355/383? Go for the cubes, but you must have the heads to support the extra 33 cid. Otherwise it wont do you any good. I also think LT motors put down much better numbers when stroked. Ls motors dont need it like LT's do, or at least what ive seen.
Id do a le3 383, t76gts, and shoot for the moon.
Heads: if you already have le2's you should be good there. But sending them back to be le3's would even be better.
355/383? Go for the cubes, but you must have the heads to support the extra 33 cid. Otherwise it wont do you any good. I also think LT motors put down much better numbers when stroked. Ls motors dont need it like LT's do, or at least what ive seen.
Id do a le3 383, t76gts, and shoot for the moon.
11-25-2008, 09:14 PM
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Well I was going to go with a D1SC kit but I talked to a buddy today and I think I am going to go with either a single T76 or twin 68mm turbos. He is more than likely going to be the one who builds the kit for me. He has a custom twin kit he built for his Firehawk and on 15PSI the car put down 808HP and 800 ft lbs. He is selling the twin 68's he has right now and I am most likely going to buy them from him.
He told me the opposite, he said that turbo's don't like cubes and that a 355 would be better than a 383. So I don't know. If I could keep the LE2 heads then that would be great and I would just look at getting more of a boost specific cam.
Right now after I get the nitrous stuff sold I am going to get a tubular K member and relocate the battery to start getting ready for the turbo kit. THen I am going to build the bottom end.
I know nothing about boost so any info would help guys.
He told me the opposite, he said that turbo's don't like cubes and that a 355 would be better than a 383. So I don't know. If I could keep the LE2 heads then that would be great and I would just look at getting more of a boost specific cam.
Right now after I get the nitrous stuff sold I am going to get a tubular K member and relocate the battery to start getting ready for the turbo kit. THen I am going to build the bottom end.
I know nothing about boost so any info would help guys.
11-25-2008, 10:28 PM
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whats he mean turbos dont like cubes? That is a completely false statement.
Twim 68s on a 383 would be perfect. Is this the guy from like garden city or w/e, black firehawk with twin t70s?
Eitherway, twin 68s, or a single t76 would be good for a 383. However, if you want to make power for cheap, i would look at a borgwarner s400 with the 1.32 A/R housing that can be had for around 600 shipped on a 383 and be good to 800/900 at the wheels.
Twim 68s on a 383 would be perfect. Is this the guy from like garden city or w/e, black firehawk with twin t70s?
Eitherway, twin 68s, or a single t76 would be good for a 383. However, if you want to make power for cheap, i would look at a borgwarner s400 with the 1.32 A/R housing that can be had for around 600 shipped on a 383 and be good to 800/900 at the wheels.
11-25-2008, 10:44 PM
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Yep Adam, this is my buddy from Garden. I just need to decide now to either go with a 355 or 383 because I am taking the block to a guy in Liberal when I go home for Turkey day and he needs to know then if he is going to clearance it for a 383 or not. Everything else is going to be the same cost since I am going with a new forged crank and rods.
11-25-2008, 10:51 PM
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I would go 383 honestly. I regret not building a 383 the first time around, and i really regret getting a small turbo and limiting power.
Heres my outlook on it, build your motor for at least 300hp more than you want, because you are going to want to grow.
I would really look into an s400 as well, the T76s are good, but if you really want to make 800, you will probably be struggling on a T76. Eric Brazaan i believe is his name just put down over 700 on 15ish psi on a 383 on a s400.
As far as a cam, look into the comp blower cam, 224/236 with mid 500s lift.
Heres my outlook on it, build your motor for at least 300hp more than you want, because you are going to want to grow.
I would really look into an s400 as well, the T76s are good, but if you really want to make 800, you will probably be struggling on a T76. Eric Brazaan i believe is his name just put down over 700 on 15ish psi on a 383 on a s400.
As far as a cam, look into the comp blower cam, 224/236 with mid 500s lift.
11-25-2008, 10:52 PM
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Also, I've been doing some reading and lots of people recommend reusing the stock rods and crank. What do you guys think about doing that? If I did that with a splayed 4 bolt, I could have about 2000 invested in a shortblock instead of 5000 and that would help me get it done quicker. What are your guys opinions on that?
11-26-2008, 02:14 PM
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Also, I've been doing some reading and lots of people recommend reusing the stock rods and crank. What do you guys think about doing that? If I did that with a splayed 4 bolt, I could have about 2000 invested in a shortblock instead of 5000 and that would help me get it done quicker. What are your guys opinions on that?
Contact roadie on here, he has a set of rods/pistons that are very nice that will hold 1000hp for sale. They're for a 383 too
Also, if your thinking of spending 5k on your shortblock, go to victoryracingengines.com you can get an all compustar with diamond piston shortblock 383 4 bolt splayed for around 3700
Last edited by reamo04; 11-26-2008 at 02:19 PM.
11-26-2008, 04:17 PM
#13
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355 = a Bit cheaper since you don't have to clearance the block, so you save on the machine work and the time to have that machining done.
You can tell by the import buzzbombs, you don't have to have big cubes to have big power.
As far as total HP, going for everything you can may not be what you really like. Look for a figure you can get to the street. I have a few friends with turbo cars that can't even get very far into the throttle before either the tires go up in smoke or murders their 'bulletproof' transmissions (one is on his 4th or 5th tranny in the past couple of years). I already had a 383 solid roller before going turbo but my research convinced me a 355 would be perfect for my HP goals (600 rwhp) and my street goals (with my suspension/tires, I can keep traction). Just ask any reputable engine builder to give you a time/money quote for a 335, then a 383 and I believe you'll see the 383 effort is more time/money hungry.
With a 383, you'll need more injector too. The high impedence 60# injectors that are about the most common upper limit injectors you can use with the stock computer and they are only good for about 600 hp at 85% duty cycle.
Like others are saying, put good forged internals and a splayed 4 bolt main conversion inside your new block, build it to handle all you can afford(mines good to 800) and you'll have a great reliable foundation for a ton of fun.
You can tell by the import buzzbombs, you don't have to have big cubes to have big power.
As far as total HP, going for everything you can may not be what you really like. Look for a figure you can get to the street. I have a few friends with turbo cars that can't even get very far into the throttle before either the tires go up in smoke or murders their 'bulletproof' transmissions (one is on his 4th or 5th tranny in the past couple of years). I already had a 383 solid roller before going turbo but my research convinced me a 355 would be perfect for my HP goals (600 rwhp) and my street goals (with my suspension/tires, I can keep traction). Just ask any reputable engine builder to give you a time/money quote for a 335, then a 383 and I believe you'll see the 383 effort is more time/money hungry.
With a 383, you'll need more injector too. The high impedence 60# injectors that are about the most common upper limit injectors you can use with the stock computer and they are only good for about 600 hp at 85% duty cycle.
Like others are saying, put good forged internals and a splayed 4 bolt main conversion inside your new block, build it to handle all you can afford(mines good to 800) and you'll have a great reliable foundation for a ton of fun.
11-27-2008, 12:43 AM
#14
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Either go stock parts 355ci or go 383 forged.. no point 355 forged without making it 383, seriously.
355 is alot cheaper using stock parts, may support 600hp.. maybe not (meaning it might blow up). Not a question on how much HP will a 355 or 383 make cause that's not the issue, it's more about driveability and overall low end power. A 383 wont break a trans that a 355 wont... it's about what your doing for boost, nitrous, or driving style, tires, etc. I know a guy that blew 3 T56's all fixed under warranty on a stock motor then GM cut him off, now mine = no problems all because of driving style (no 6200rpm dumps at 80mph)
Really if your running a larger cam with a manual trans and want more chance at better low end go with 383. If it's a small cam auto then screw it.
Now, if you dont want to chance it and want to skip going throught he whole entire process 2times then go 383 with new forged internals, cause anybody in their right mind supercharging a 355 will keep pushing it.. and if your gonna keep pushing it then dont bother worrying about the stock rods and crank.. step it up to the good stuff. Do it once do it right.
Now, if your throwing on some heads and cam on a stock block then who cares, stock is fine... worse case you throw a rod and piston bends a valve, during the rebuild U can fix the valve. Not worth it if you rebuilt a 355 and it blows cause you pushed it too far 1yr after you got it running.
I started out basic Summit forged 383 and getting machine work done locally and building myself.. then realized for not that much more (reletively speaking) I could have a pro build it with top end parts and not have to worry about all the clearances getting them just right that I would never do...
355 is alot cheaper using stock parts, may support 600hp.. maybe not (meaning it might blow up). Not a question on how much HP will a 355 or 383 make cause that's not the issue, it's more about driveability and overall low end power. A 383 wont break a trans that a 355 wont... it's about what your doing for boost, nitrous, or driving style, tires, etc. I know a guy that blew 3 T56's all fixed under warranty on a stock motor then GM cut him off, now mine = no problems all because of driving style (no 6200rpm dumps at 80mph)
Really if your running a larger cam with a manual trans and want more chance at better low end go with 383. If it's a small cam auto then screw it.
Now, if you dont want to chance it and want to skip going throught he whole entire process 2times then go 383 with new forged internals, cause anybody in their right mind supercharging a 355 will keep pushing it.. and if your gonna keep pushing it then dont bother worrying about the stock rods and crank.. step it up to the good stuff. Do it once do it right.
Now, if your throwing on some heads and cam on a stock block then who cares, stock is fine... worse case you throw a rod and piston bends a valve, during the rebuild U can fix the valve. Not worth it if you rebuilt a 355 and it blows cause you pushed it too far 1yr after you got it running.
I started out basic Summit forged 383 and getting machine work done locally and building myself.. then realized for not that much more (reletively speaking) I could have a pro build it with top end parts and not have to worry about all the clearances getting them just right that I would never do...
11-27-2008, 10:45 AM
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After doing a lot of research I decided to go with an all-forged 355. The reasoning was that the geometry of the cranks, pistons, etc was going to be better and will most likely give me more reliability when consistantly going to 6500 - 7000 RPM. Aso, if smething gives up in the motor I still have room to clearance the block at that time.
The 383 will give a slightly better shove down low but it isn't as crucial on a well built turbo car. I'd say the heads you choose will be morw important than your cube question.
The 383 will give a slightly better shove down low but it isn't as crucial on a well built turbo car. I'd say the heads you choose will be morw important than your cube question.
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