346 or bigger for a procharger?
Originally Posted by QSPres
Yup...
Again, the heavier the bottom end, the more you want to spin it, the more you'll break parts. So, you spend more on lighter parts...
Again, the heavier the bottom end, the more you want to spin it, the more you'll break parts. So, you spend more on lighter parts...
Still trying to figure out why you think I would have to spin a 408 more than a 346? RPM is RPM, regardless. Doesn't make sense.
I think he's just saying that stroker motors have more rotating mass due to the longer stroke. I don't think that is a real issue here or even on most LS1 strokers. Unless you are going with a stroke of over 4'' but not to many people do that.
Originally Posted by mikep2002
I love this stuff as I am also facing this question as to 346/383. I understand not needing the extra cubes to make big power but heres what i think about and ive asked the same question and most people agree....
in theory, a supercharger wont need to work as hard to produce the same amount of power on a 402 as it would on a 346ci. therefore putting less stress on the internals of the motor???
346 w/D1-SC@12psi on pump gas will produce what...560-590hp??
402 w/D1-SC may only need 9-10psi to produce the same amount of power. also takin into consideration that both motors are forged and have equal bolts ons...(injectors, fuel pump, intake, etc etc)
am i wrong?? someone educate me if i am lookin at it the wrong way. cause i just purchased a forged 402 for my current project which i plan on running a D1 on...looking for 650rwhp.
in theory, a supercharger wont need to work as hard to produce the same amount of power on a 402 as it would on a 346ci. therefore putting less stress on the internals of the motor???
346 w/D1-SC@12psi on pump gas will produce what...560-590hp??
402 w/D1-SC may only need 9-10psi to produce the same amount of power. also takin into consideration that both motors are forged and have equal bolts ons...(injectors, fuel pump, intake, etc etc)
am i wrong?? someone educate me if i am lookin at it the wrong way. cause i just purchased a forged 402 for my current project which i plan on running a D1 on...looking for 650rwhp.
Originally Posted by TNTramair
I understand not needing the extra cubes to make big power but heres what i think about and ive asked the same question and most people agree.....
in theory, a supercharger wont need to work as hard to produce the same amount of power on a 402 as it would on a 346ci. therefore putting less stress on the internals of the motor???.
in theory, a supercharger wont need to work as hard to produce the same amount of power on a 402 as it would on a 346ci. therefore putting less stress on the internals of the motor???.
Huh? A supercharger doesn't know what its on. It will blow a certain amount of air per revolution. If all that air makes it into the combustion chamber before ignition, it burns. If a 402 has a bigger bore than a 346, and the supercharger can supply the additional air to fill that space, it will make more power. If it can't than it won't.
PSI means nothing for this discussion. Its all about VE, volumetric efficiency. A properly sized blower on a 346 will make far more power than the same sized blower on a 402. Why? Because it can't supply enough air to bring the VE of the 402 up!
The 402 has a heavier rotating assembly, which places more stress on the main caps, rods, bolts, and pistons. The faster you spin it, the more stress is applied. The 346 has the opposite problem, in that it stresses itself less, but must rev faster to produce the same power (pump as much air). So you get wear on things like valve springs, bearings, rings and cylinder walls.
For a street car, it almost doesn't matter, but if you're planning on racing, its a delicate balancing act.
Originally Posted by TS6
Still trying to figure out why you think I would have to spin a 408 more than a 346? RPM is RPM, regardless. Doesn't make sense.
Never said you'd have to spin it more.
It's just more wear on the bottom end because of the weight.
RPM isn't RPM sometimes. Reason why a nitrous motor is less durable than a turbo....
well now that my brain is a liquid past like ooz...is a 383 easier to tune than a 400+ ci? how does a zo6 cam behave in a 383 or is there better options? also is the 383 on the ragged edge for the block or could it still take a cleaning and rebuilding? im looking for north of 700 rwhp. i just had the install done of the d-1sc and although 470 rwhp is fun.... like you all have said it leaves you hungry for more. im looking at larger ci mostly for a little more down low torque. as i drive now on cheap 315's (ten bolt) at the top of first the tires break free, second gear is useless and either third graps, the clutch goes up in smoke, or the pedal sticks to the floor.(stock clutch, i got a twin disk to go in, in the spring). im looking for a earlier torque hit so when i order the 9" and get some stickies it takes off like a raped ape with out gearing it lower than 3.42's. id be happy with a forged 346 if i could get my goals out of it. keep the thoughts coming. im currently looking at texas speed and spdc's shortblocks. thanks
Last edited by ZDOG; Nov 25, 2006 at 05:05 PM.
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Verdad Gallardo [QUOTE=QSPres]
PSI means nothing for this discussion. Its all about VE, volumetric efficiency. A properly sized blower on a 346 will make far more power than the same sized blower on a 402. Why? Because it can't supply enough air to bring the VE of the 402 up!
QUOTE]
Care to rethink that?
Do you actually have any experience with this stuff?
PSI means nothing for this discussion. Its all about VE, volumetric efficiency. A properly sized blower on a 346 will make far more power than the same sized blower on a 402. Why? Because it can't supply enough air to bring the VE of the 402 up!
QUOTE]
Care to rethink that?
Do you actually have any experience with this stuff?
I thought boost was a measure of back pressure which is why hondas and teminators have bigg boost readings as the VE is inefficient? The lsx flows better, is bigger and registers lower boost with bigger (or the same) hp numbers with (the same) less boost?
Originally Posted by ZDOG
well now that my brain is a liquid past like ooz...is a 383 easier to tune than a 400+ ci? how does a zo6 cam behave in a 383 or is there better options? also is the 383 on the ragged edge for the block or could it still take a cleaning and rebuilding? im looking for north of 700 rwhp. i just had the install done of the d-1sc and although 470 rwhp is fun.... like you all have said it leaves you hungry for more. im looking at larger ci mostly for a little more down low torque. as i drive now on cheap 315's (ten bolt) at the top of first the tires break free, second gear is useless and either third graps, the clutch goes up in smoke, or the pedal sticks to the floor.(stock clutch, i got a twin disk to go in, in the spring). im looking for a earlier torque hit so when i order the 9" and get some stickies it takes off like a raped ape with out gearing it lower than 3.42's. id be happy with a forged 346 if i could get my goals out of it. keep the thoughts coming. im currently looking at texas speed and spdc's shortblocks. thanks
The 383 is just the same bore as the 346, but with a longer stroke, you would use a 4.0 stroke on the crank to make a 382/383. Put a 4.0 stoke in a 6.0 LS2 block and you would have a 402.
Your 346 block turned into a 383 is a great combination, you will need a new fuel system to accomodate it, and expect 700+ rwhp. Bob
hp is based off a flow of air and fuel... it doesnt matter if its a 502 with a d1sc on it or a 346.... the one that flows more air will make more power.... and a 502 will make more power off idle with a centri than a 346 will because it makes more NA.... your theory of a 346 will make more hp with a d1 than a 408 with a d1 is wishful thinking...
You are limited by the amount of air the blower can make, while a more effiecient setup (CID, heads/cam) will make slightly more/less power with that same amount of air it all depends on what you want to do.
I think a 346/D1SC is a pretty good combination but what do I know. I honestly dont think I would run any better with a 370/402 or whatever if that was the only change I made unless I stepped up the size of the blower.
I think a 346/D1SC is a pretty good combination but what do I know. I honestly dont think I would run any better with a 370/402 or whatever if that was the only change I made unless I stepped up the size of the blower.
Originally Posted by kp
You are limited by the amount of air the blower can make, while a more effiecient setup (CID, heads/cam) will make slightly more/less power with that same amount of air it all depends on what you want to do.
I think a 346/D1SC is a pretty good combination but what do I know. I honestly dont think I would run any better with a 370/402 or whatever if that was the only change I made unless I stepped up the size of the blower.
I think a 346/D1SC is a pretty good combination but what do I know. I honestly dont think I would run any better with a 370/402 or whatever if that was the only change I made unless I stepped up the size of the blower.
but yes, its not going to affect PEAK cfm because the blower will only push so much... but a bigger motor i think will effect how soon it sees that peak cfm....
this is only theory because i have never swapped out motor combos on the exact same blower...
but id also say you might also see a slight decrease in IAT's
Originally Posted by QSPres
Tom Byrne of Tbyrne Motorsports
Pat Burke of Ocean State Performance
Jason Enos
Manny Buginga
Just a few of my friends. Wanna ask again?
Pat Burke of Ocean State Performance
Jason Enos
Manny Buginga
Just a few of my friends. Wanna ask again?
And? No offense, but I have friends who are good at **** too. I have a friend thats going to be building a Studebaker truck for Boyd Coddington (Boyd isn't anywhere near as talented as this guy). I can't paint a ******* barn red, so what is your point? I didn't ask if your friends have any experience, I asked if you did.
I'll bet you anything if you pulled my motor (408) and put in a built 346 and left everything the same it would make less power. I would love to hear some real reasons why you think a 346 would make more power. Boost is a function of backpressure. Bigger motors flow more air and allow more of the blowers air to make it through the engine therefor making more power.
hey Bob, can you chime in on this conversation, I know you build and dyno all different kinds of procharger motors and I figure you would have some good input will real numbers to share for us
Originally Posted by TS6
And? No offense, but I have friends who are good at **** too. I have a friend thats going to be building a Studebaker truck for Boyd Coddington (Boyd isn't anywhere near as talented as this guy). I can't paint a ******* barn red, so what is your point? I didn't ask if your friends have any experience, I asked if you did.
I'll bet you anything if you pulled my motor (408) and put in a built 346 and left everything the same it would make less power. I would love to hear some real reasons why you think a 346 would make more power. Boost is a function of backpressure. Bigger motors flow more air and allow more of the blowers air to make it through the engine therefor making more power.
I'll bet you anything if you pulled my motor (408) and put in a built 346 and left everything the same it would make less power. I would love to hear some real reasons why you think a 346 would make more power. Boost is a function of backpressure. Bigger motors flow more air and allow more of the blowers air to make it through the engine therefor making more power.