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Another $$$$ to performance.

This is a discussion on Another $$$$ to performance. within the Internal Engine forums, part of the LSx Technical Help Section category; Jones not trying to be a dick but as far as the l92's being to large for a 6.0 is ...

  1. #41
    Senior Member redbird555's Avatar
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    Jones not trying to be a dick but as far as the l92's being to large for a 6.0 is simply not true, after all GM puts the l92s on the new 6.0s like the l76 even the l92 is only 12ci bigger than 6.0 so the difference isnt much. The 6.0 engines seem to love the larger runners and airflow they are even working on a version to fit the smaller bore ls1/6. Heres some links done on stock cubes and custom cams. If a custom cam is spec'd it seems the l92s are better in almost every way until you start spending mega cash on cathedrals.
    http://www.ls1tech.com/forums/dynamo...p-446rwtq.html

    http://www.ls1tech.com/forums/dynamo...76-intake.html

    http://www.ls1tech.com/forums/dynamo...s-508rwhp.html

  2. #42
    Member Jay37's Avatar
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    EDIT

    damn internet


    I deleted the post between the two... I find myself saying to much on the interenet lol
    Last edited by Jay37; 01-05-2011 at 05:29 PM.

  3. #43
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by redbird555 View Post
    Jones not trying to be a dick but as far as the l92's being to large for a 6.0 is simply not true, after all GM puts the l92s on the new 6.0s like the l76 even the l92 is only 12ci bigger than 6.0 so the difference isnt much. The 6.0 engines seem to love the larger runners and airflow they are even working on a version to fit the smaller bore ls1/6. Heres some links done on stock cubes and custom cams. If a custom cam is spec'd it seems the l92s are better in almost every way until you start spending mega cash on cathedrals.
    http://www.ls1tech.com/forums/dynamo...p-446rwtq.html

    http://www.ls1tech.com/forums/dynamo...76-intake.html

    http://www.ls1tech.com/forums/dynamo...s-508rwhp.html

    I'm not impressed, and the proof is in the dyno's. On all those examples you have peak torque occuring at 5,000 rpm or higher. Sucks for a street car. It's fine if you want to run 4.56 gears That's a very peaky engine with only about 1,400 rpms between peak torque and peak HP.
    It would be a pooch on the street below that.

    Intake runner is too large for that size engine, plain and simple. Ya it makes peak HP, but you have to look at the total package.

    Those heads only flow about 300 cfm out of the box. That's not all that great for a 270 cc intake runner when you consider a 215cc intake runner can flow the same amount in a cathedral port head.

    You have to look at intake port runner size verses flow aquired. See the difference now??

    I guarantee you I can build that same size engine with cathedral heads that flow 300-320 cfm on a 215-220 cc intake runner, and it will make near or the same peak power as the L92's but it will blow the torque curve out of the water, have better throttle response, be a total blast on the street, better gas mileage, and I won't have to run as much gear to make it happy either.

    The only reason people are using those heads is the simple fact that they are cheap. That doesn't equate to the best package.

  4. #44
    Member Jay37's Avatar
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    with the 5.3 head on a 408 thing... I ran numbers on it.

    zero deck and flat top pistons. .040 gasket 59cc heads. my calculater came up with 13.41 LOL, but for real? Im not going to run those heads without a tight quench because that just doesn't make sense, and even with valve reliefs I can't get below 13.


    I would like even a little tighter quench than that, especially if I'm paying for forged parts, so clearly I would need a larger chamber head.

    fuck.

    what is the volume on dang L92 heads or whatever ya'all are talking about?
    I'm currently scratching my head haha.

  5. #45
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by Jay37 View Post
    with the 5.3 head on a 408 thing... I ran numbers on it.

    zero deck and flat top pistons. .040 gasket 59cc heads. my calculater came up with 13.41 LOL, but for real? Im not going to run those heads without a tight quench because that just doesn't make sense, and even with valve reliefs I can't get below 13.


    I would like even a little tighter quench than that, especially if I'm paying for forged parts, so clearly I would need a larger chamber head.

    fuck.

    what is the volume on dang L92 heads or whatever ya'all are talking about?
    I'm currently scratching my head haha.
    Yep, I knew it was going to be high.

  6. #46
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    Those flow numbers make me drool, really I had to get up and get a napkin. anyway, those l92 300cfm would make up to like 600hp right? If they are making power on a stock engine it does seem kind of odd. Seems like they would have slower throttle response and lack a little torque on a engine that moves less air. you might not see it on the dyno.

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    a 76cc head would give me 11 to 1...

    any suggestions?

    If I was to run 5.3 heads on 400ci plus engine... I'm sure it makes power, but you would have to pull the piston away from the head.
    They would

    Also for shitts, same set up on a non stroker so a 369ci, because it would be bored. is still 12.2 to 1 again have to pull the piston away.

    Not trying to be anal, but on a 500hp plus engine these are things to think about.
    Last edited by Jay37; 01-05-2011 at 05:57 PM.

  8. #48
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    Quote Originally Posted by Jay37 View Post
    Those flow numbers make me drool, really I had to get up and get a napkin. anyway, those l92 300cfm would make up to like 600hp right? If they are making power on a stock engine it does seem kind of odd. Seems like they would have slower throttle response and lack a little torque on a engine that moves less air. you might not see it on the dyno.
    You are right, they will have slower throttle response and lack torque. You can see it on the dyno with that peaky torque curve.
    Not hitting peak torque until 5,000 or 5,200,,,then peaking on HP at 6,400 rpm. Talk about your very short usable rpm range. Sheeesh
    Better have a close ratio gear box and stiff 4.56-4.88 gears if you run a real tire on it.

    Looks more like the curve of a very peaky little 302 I built

  9. #49
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    Quote Originally Posted by Jay37 View Post
    a 76cc head would give me 11 to 1...

    any suggestions?
    Fine for pump gas with the right camshaft and a nice tune on an aluminum head.

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    There is a reason not alot of people run the L92

  11. #51
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    Quote Originally Posted by Jay37 View Post
    Those flow numbers make me drool, really I had to get up and get a napkin. anyway, those l92 300cfm would make up to like 600hp right? If they are making power on a stock engine it does seem kind of odd. Seems like they would have slower throttle response and lack a little torque on a engine that moves less air. you might not see it on the dyno.
    You really have to look at those flow numbers and consider the port volume too.
    Ya flowing 300 cfm is great, but look at the size of the intake runner,,,,270 or 275 cc. The I/E ratio also leaves alot to be desired.

    Cathedral ports can flow 300-320 cfm as well and do it with smaller 215-220 cc intake runners. Costs more, but you'll have a happier engine.

    It's the price of those L92's that are making them so attractive to budget builders.

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    Quote Originally Posted by Firebirdjones View Post
    Fine for pump gas with the right camshaft and a nice tune on an aluminum head.
    Right on, thats why I ran different head cc numbers, to find the "perfect world" volume head lol.

    Also a 16 cc dish would give me about 11 to 1 with the 59cc head... so I kind of jumped the gun on ruling them out.

  13. #53
    Senior Member redbird555's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    I'm not impressed, and the proof is in the dyno's. On all those examples you have peak torque occuring at 5,000 rpm or higher. Sucks for a street car. It's fine if you want to run 4.56 gears That's a very peaky engine with only about 1,400 rpms between peak torque and peak HP.
    It would be a pooch on the street below that.

    Intake runner is too large for that size engine, plain and simple. Ya it makes peak HP, but you have to look at the total package.

    Those heads only flow about 300 cfm out of the box. That's not all that great for a 270 cc intake runner when you consider a 215cc intake runner can flow the same amount in a cathedral port head.

    You have to look at intake port runner size verses flow aquired. See the difference now??

    I guarantee you I can build that same size engine with cathedral heads that flow 300-320 cfm on a 215-220 cc intake runner, and it will make near or the same peak power as the L92's but it will blow the torque curve out of the water, have better throttle response, be a total blast on the street, better gas mileage, and I won't have to run as much gear to make it happy either.

    The only reason people are using those heads is the simple fact that they are cheap. That doesn't equate to the best package.
    I will agree with you on the fact the peak numbers are high however but close to 400 ft lbs of torque everywhere under the curve will not make a slouch street car hell i dont see many ls1/2/6 cammed cars with budget heads making torque like that under the curve. Once again if these heads should only be used on 400 or more ci why did gm switch their current 6.0 and 6.2 platforms to them I realize the new engines employ vvt and afm sometimes but not all the time and even so vvt would be the only thing that may help the heads and even that is marginal.

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    Alright grigo, Mr. jones, I was hard headed, on the 5.3 stage 2.5 heads. BUT ya'all have me now sold. seems I can push the piston out of the cylinder .005, get me one of them nice and tight .035 quench areas. with a .040 mls gasket. Then to compensate for the large bore on small head check it out http://texas-speed.com/shop/item.asp Yup thats a -20cc dish so with that piston up close compression would still only be 10.7! perfect. sounds pretty sweet to me.

    What do ya'all think? New to these engines performance wise, but that seems like a "happy combo" ya'all came up with.

    Some reason I blanked on running the negative dish when I was trying to figure c/r's. Probably has to do with crashing cars in early childhood.

    EDIT damnit the link doesn't work, either way its -20cc dish pistons with a 408. balanced and all for like 2g. thats not bad.
    Last edited by Jay37; 01-05-2011 at 06:44 PM.

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    Quote Originally Posted by redbird555 View Post
    i dont see many ls1/2/6 cammed cars with budget heads making torque like that under the curve.
    And you probably won't, you are talking about a smaller motor with less bore.

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    Quote Originally Posted by redbird555 View Post
    I will agree with you on the fact the peak numbers are high however but close to 400 ft lbs of torque everywhere under the curve will not make a slouch street car .

    Why settle for close to 400 ft lbs. under the curve when you can have more, and still make the same peak HP ???

    Is it because the heads are cheaper to buy?? We know the answer to that one.
    Last edited by Firebirdjones; 01-05-2011 at 07:05 PM.

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    Correct me if I'm wrong but a head(the 5.3 2.5) that flows 254cfm @.400 and 291cfm@.500 is going to make serious power. I am really impressed with those numbers. my old fuelies would be lucky to flow 210@.500 and that gen 1 set up is always worth 400 plus with nasty throttle response.
    Last edited by Jay37; 01-05-2011 at 06:59 PM.

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    Quote Originally Posted by redbird555 View Post
    Once again if these heads should only be used on 400 or more ci why did gm switch their current 6.0 and 6.2 platforms to them I realize the new engines employ vvt and afm sometimes but not all the time and even so vvt would be the only thing that may help the heads and even that is marginal.
    It's one reason why GM incorporated the variable valve timing, for more low end torque and better mileage, something these engines were lacking. It helps more than you are leading on. Have you ever played with advancing/retarding a cam on the dyno and watch the power curve change? Even 2 degrees makes a nice difference.

    Once again, look at those peaky torque curves. That's a result of a 270cc intake runner on a little 364. Not that great of a combo. That's why I suggested 400 cubes or more to take advantage of all that port volume, Is it absolutely necessary??? No,,,but you'll have a better torque curve and make more HP to boot. You don't have to take my advice, I'm just here to help..
    People will still continue to use these heads because they are cheap, that's why they sell. People throw them on small cubed stock short blocks and make a big HP number,,,that's all most people seem to care about and they don't look at the big picture.

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    Quote Originally Posted by Jay37 View Post
    Correct me if I'm wrong but a head that flows 254cfm @.400 and 291cfm@.500 is going to make serious power.
    Yes,,and the less intake runner volume you have to flow those numbers the more port velocity you have, which equates to better throttle response, more low end torque and a flatter,,,,longer torque curve throughout the rpm range while still making the same peak HP.

    That's why the intake runner cc is just as important as the flow numbers they produce.

    If you are building a 350 and have 2 sets of heads that flow 300 cfm,,,,one has a 220 cc intake runner and the other has a 270cc intake runner,,,just about every engine builder out there is going to pick the smaller 220 cc intake runner hands down.

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    who cares about those damn huge heads L92 obviously there not going to make real power, power that is evenly distrubuted and usable with throttle response, there is just too much volume to get the velocity up there.

    Seems to me like those 5.3 stage 2.5 heads would even be on the big end for a 408 inch engine even spun to up 7,000?

    Jones... I totally agree, I have seen time and time again street engines being held up by huge heads, carb, intake. or whatever. It just kills the power, seems we don't ever seem to be on the same page as each other LOL. I am seriously scratching my head because I am really considering ordering some parts. I have mapped out alot of gen1 small blocks I am not going to put out cc's and such, but they are WAY smaller than any of the mentioned heads and make good street power let these guys think what they want.

    That is why alot of the time you are better off just ordering a long block, a 405 hp. happy long block would have a good shot at killing some 500plus hp car that is just put together with parts that aren't happy with each other.
    Last edited by Jay37; 01-05-2011 at 07:20 PM.

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