best compression ratio for vortech and cams
06-29-2011, 02:43 AM
#2
I'm assuming that your going for broke and doing a full build, other wise you wouldnt be asking this...
It all depends, if you plan on staying in the <10psi area, no need to build the bottom end stock compression ratio is great, you'll actually make more power on the stock block than if you build it, however if you are going for broke i would say probably something like 9:1 or 9.5:1 for a S/C
As for cams, I would look for something like the GTM stg1 or stg2 S/C cams...
http://www.gtmotorsports.com/product...cat=264&page=1
It all depends, if you plan on staying in the <10psi area, no need to build the bottom end stock compression ratio is great, you'll actually make more power on the stock block than if you build it, however if you are going for broke i would say probably something like 9:1 or 9.5:1 for a S/C
As for cams, I would look for something like the GTM stg1 or stg2 S/C cams...
http://www.gtmotorsports.com/product...cat=264&page=1
06-29-2011, 05:11 AM
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how do you know you need cams? all depends on what boost pressure you intend on running and intended rpm range
compression - depends on your intended fuel, and the capabilities of your tuner
compression - depends on your intended fuel, and the capabilities of your tuner
06-29-2011, 06:34 AM
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i am confused.. what do you mean by broke and doing a full build? i blew my motor last year so i am building my bottom end. i am aiming for 450whp safely with my new build.. so im thinking i would need cams in order to get there... i have 550cc injectors with the walbro right now. i might get a fuel return kit if i need it.. i also plan on doing water/meth kit. But just wasnt sure what compression ratio pistons work best with a supercharger.
06-29-2011, 06:38 AM
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i have the 928 impeller upgrade on my vortech and currently have the 3.13 pulley but i am upgrading to 2.87 pulley on my new motor..
I'm assuming that your going for broke and doing a full build, other wise you wouldnt be asking this...
It all depends, if you plan on staying in the <10psi area, no need to build the bottom end stock compression ratio is great, you'll actually make more power on the stock block than if you build it, however if you are going for broke i would say probably something like 9:1 or 9.5:1 for a S/C
As for cams, I would look for something like the GTM stg1 or stg2 S/C cams...
http://www.gtmotorsports.com/product...cat=264&page=1
It all depends, if you plan on staying in the <10psi area, no need to build the bottom end stock compression ratio is great, you'll actually make more power on the stock block than if you build it, however if you are going for broke i would say probably something like 9:1 or 9.5:1 for a S/C
As for cams, I would look for something like the GTM stg1 or stg2 S/C cams...
http://www.gtmotorsports.com/product...cat=264&page=1
06-29-2011, 06:48 AM
#7
your original post was a bit mis leading in the fact that you were just asking for a compression ratio and didnt mention that you had already blown your motor and as i thought were building the bottom end, with that in mind, 450 is easy to do, i know theres several guys that have done it on stock cams, others have used a 264 or 272 stye cam. i would go with the 9:1 pistons.
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06-29-2011, 07:04 AM
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thanks for your help! the reason i ask what compression ratio is most brands of pistons im looking at doesnt have 9:1... the CP pistons have 8.5:1 or the wiseco have 8.8:1. Is there a brand you recommend? i am going with the eagle rods.
your original post was a bit mis leading in the fact that you were just asking for a compression ratio and didnt mention that you had already blown your motor and as i thought were building the bottom end, with that in mind, 450 is easy to do, i know theres several guys that have done it on stock cams, others have used a 264 or 272 stye cam. i would go with the 9:1 pistons.
06-29-2011, 07:41 AM
#9
There were a few threads on here that had guys saying that if you were building a bottom end for a supercharger to go 11:1 compression ratio. For turbo applications you want lower compression because the boost comes on sooner with a turbo. With lower compression on a S/C I have read that the low to midrange power will suffer. I would do a little searching on here before you go out and buy bottom end parts. Again, that is just what I have read in other threads on here.
06-29-2011, 07:58 AM
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i have been doing alot of research but not finding what im looking for. Most people with built blocks that are supercharged got their blocks from someone and it just says like Stage 1 shortblock, doesnt really say what compression pistons they used. A few said to go with 9 and 9.5 but dont know what companies make those compression ratios..
There were a few threads on here that had guys saying that if you were building a bottom end for a supercharger to go 11:1 compression ratio. For turbo applications you want lower compression because the boost comes on sooner with a turbo. With lower compression on a S/C I have read that the low to midrange power will suffer. I would do a little searching on here before you go out and buy bottom end parts. Again, that is just what I have read in other threads on here.
06-29-2011, 08:57 AM
#14
Don't waste your money buying new valves to raise your compression .2......
If this is a street car, you will not be happy with anything less than 10:1. It will be mushy and not come alive in till the upper RPM Range...with less than 10:1
Why would you want to lower the compression?
What would be the Reason? These SC's work fine with stock CR....on 91 Octane.
If this is a street car, you will not be happy with anything less than 10:1. It will be mushy and not come alive in till the upper RPM Range...with less than 10:1
Why would you want to lower the compression?
What would be the Reason? These SC's work fine with stock CR....on 91 Octane.
06-29-2011, 11:34 AM
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problem is that the cam is going to want to be at an rpm that the s/c may not agree with
to the OP - pistons come in 2 typical flavors, off the shelf and custom. The custom stuff doesn't cost more, it just takes a long time to make. However, nearly every piston manufacturer we deal with (CP, Wiseco, JE, etc) will speed up production for an additional fee, allowing you to get the exact compression ratio you want without touching valves, etc
A vortech is not a bottom end setup - its strengths are in the mid to top end. Cam wise, you need to ask Vortech what the blower will reliably spin to with your desired pulley and from there that will narrow the field for cam choices. Within those choices, you really need the cam cards, or someone familiar with each choice, to see which will accentuate what the blower brings to the table. Just slapping a random set in without this info can leave you potentially worse off than stock cams would be. Sure, the higher lift, higher duration may net you a higher peak, but it may come at a significant cost to area under the curve. All has to be taken into consideration
to the OP - pistons come in 2 typical flavors, off the shelf and custom. The custom stuff doesn't cost more, it just takes a long time to make. However, nearly every piston manufacturer we deal with (CP, Wiseco, JE, etc) will speed up production for an additional fee, allowing you to get the exact compression ratio you want without touching valves, etc
A vortech is not a bottom end setup - its strengths are in the mid to top end. Cam wise, you need to ask Vortech what the blower will reliably spin to with your desired pulley and from there that will narrow the field for cam choices. Within those choices, you really need the cam cards, or someone familiar with each choice, to see which will accentuate what the blower brings to the table. Just slapping a random set in without this info can leave you potentially worse off than stock cams would be. Sure, the higher lift, higher duration may net you a higher peak, but it may come at a significant cost to area under the curve. All has to be taken into consideration
......... but stay with the Vortech then
07-01-2011, 09:06 AM
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i called a few shops.. some are telling me to go with 10:1 and some are telling me to go with 8.8:1. stock is 10.3:1 correct?? what should i get??