can heads flow to much??
03-23-2008, 08:51 PM
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can heads flow to much?? the reason i ask is im thinkin of building a 5.0destroked ls and can a really really good flowing set of heads hurt my performance since it doesnt need as much as say a 383 or 408??
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03-24-2008, 04:53 AM
#10
yes... lol. absolutely. for a motor that is ONLY going to see the racetrack, you can get away with a lot. if you drive on the street even 20% of the time with a motor built for all-out high rpm performance, youll absolutely hate it and probably sell it. the key to it all is keeping your port velocity up, by matching the heads to a cam to an intake/TB combo.
port velocity is whatll make your motor fun to drive, with snappy, instant torque and decent low rpm manners where youll be doing the majority of your street driving. and if you plan to go 7k rpms and up, ditch the hydraulic rollers and go with solids. i wouldnt even consider hydraulics for this type of application. hydraulics do NOT like RPMs, they pump up and cause valvetrain instability and the only drawback in any way to solids is setting valve lash every now and then. valve lash isnt that hard to deal with and can give you easily another 1k in rpms that you can turn without valve float issues. solids for high rpm motors rock.
keep in mind, there is no replacement for displacement and the same setup on a full sized 346ci LS1 would ultimately make for a faster car, but the ability to run a destroked motor like what you're describing would benefit two things in my mind... for one, it would be nice on a track(not a dragstrip) because you could keep the RPM's up all the time with less stress on the motor and have nice top end power with more revs to effectively use before you had to shift. two, it would have a lot of "oh-god-this-is-fun" factor because you could rev the **** out of it and the higher you rapped it up the harder it would pull.
remember that a smaller, destroked motor will create less "vaccum" (its really a pressure difference equalizing itself) inside of the motor so a camshaft and set of heads that does fantastic on a larger, say 346 ci motor would not flow as efficiently and youll end up with a dog-motor. if you put a fast 92/92 on it with a vindicator camshaft it would be a dog. cubic inches let ya use a bigger cam and intake/heads/headers etc etc and it will still run great everywhere but a smaller motor can be drowned out by those same pieces. youd get owned by every honda in town because youd have to wait for your rpms to get above 4 grand to make any power at all, and by that point you have lost so much ground you're screwed. a 4k stall on the street would suck, too.
a realistically priced destroked motor that would be right up your alley would have some patriot ls6 cnc heads, titanium retainers, a 224-228 cam, fast 78/78 TB or possibly a fast 90/90, some 1 7/8 headers, and a set of eagle or scat lightweight H- beams and lightweight forged pistons to take some weight off the rotating assembly. the intake / TB combo is hard to gauge. id think the fast 90/90 setup might be a bit too much for that, by hurting your lowend torque. at the same time, it could certainly use the larger 90mm setup for higher rpms. and i think an ls6 intake would be fantastic up to 6 grand or 6500, but choke your top end a bit beyond that. its kinda in the middle. id probably try a 78mm fast personally. I cant say anything for sure, Ive never played with a destroked lsx motor.
a real killer setup of a motor would be some nice TFS 215's or afr 205's with a fast 90/90 combo, an aluminum flywheel, titanium or hollow stem valves, titanium retainers, a 228/230 cam, a nice set of valvesprings, lightweight pistons, titanium or lightweight billet rods, lightweight solid lifters, etc... in essence lighten anything that moves as much as you can. then you have something that performs like a ferrari where when you snap the throttle it raps up like a crotchrocket with instant throttle response and an engine note that screams up to 8 grand or better. big $$$ tho.
port velocity is whatll make your motor fun to drive, with snappy, instant torque and decent low rpm manners where youll be doing the majority of your street driving. and if you plan to go 7k rpms and up, ditch the hydraulic rollers and go with solids. i wouldnt even consider hydraulics for this type of application. hydraulics do NOT like RPMs, they pump up and cause valvetrain instability and the only drawback in any way to solids is setting valve lash every now and then. valve lash isnt that hard to deal with and can give you easily another 1k in rpms that you can turn without valve float issues. solids for high rpm motors rock.
keep in mind, there is no replacement for displacement and the same setup on a full sized 346ci LS1 would ultimately make for a faster car, but the ability to run a destroked motor like what you're describing would benefit two things in my mind... for one, it would be nice on a track(not a dragstrip) because you could keep the RPM's up all the time with less stress on the motor and have nice top end power with more revs to effectively use before you had to shift. two, it would have a lot of "oh-god-this-is-fun" factor because you could rev the **** out of it and the higher you rapped it up the harder it would pull.
remember that a smaller, destroked motor will create less "vaccum" (its really a pressure difference equalizing itself) inside of the motor so a camshaft and set of heads that does fantastic on a larger, say 346 ci motor would not flow as efficiently and youll end up with a dog-motor. if you put a fast 92/92 on it with a vindicator camshaft it would be a dog. cubic inches let ya use a bigger cam and intake/heads/headers etc etc and it will still run great everywhere but a smaller motor can be drowned out by those same pieces. youd get owned by every honda in town because youd have to wait for your rpms to get above 4 grand to make any power at all, and by that point you have lost so much ground you're screwed. a 4k stall on the street would suck, too.
a realistically priced destroked motor that would be right up your alley would have some patriot ls6 cnc heads, titanium retainers, a 224-228 cam, fast 78/78 TB or possibly a fast 90/90, some 1 7/8 headers, and a set of eagle or scat lightweight H- beams and lightweight forged pistons to take some weight off the rotating assembly. the intake / TB combo is hard to gauge. id think the fast 90/90 setup might be a bit too much for that, by hurting your lowend torque. at the same time, it could certainly use the larger 90mm setup for higher rpms. and i think an ls6 intake would be fantastic up to 6 grand or 6500, but choke your top end a bit beyond that. its kinda in the middle. id probably try a 78mm fast personally. I cant say anything for sure, Ive never played with a destroked lsx motor.
a real killer setup of a motor would be some nice TFS 215's or afr 205's with a fast 90/90 combo, an aluminum flywheel, titanium or hollow stem valves, titanium retainers, a 228/230 cam, a nice set of valvesprings, lightweight pistons, titanium or lightweight billet rods, lightweight solid lifters, etc... in essence lighten anything that moves as much as you can. then you have something that performs like a ferrari where when you snap the throttle it raps up like a crotchrocket with instant throttle response and an engine note that screams up to 8 grand or better. big $$$ tho.
Last edited by nine-eight; 04-03-2008 at 05:53 PM.
03-24-2008, 10:32 PM
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yes... lol. absolutely. for a motor that is ONLY going to see the racetrack, you can get away with a lot. if you drive on the street even 20% of the time with a motor built for all-out high rpm performance, youll absolutely hate it and probably sell it. the key to it all is keeping your port velocity up, by matching the heads to a cam to an intake/TB combo.
port velocity is whatll make your motor fun to drive, with snappy, instant torque and decent low rpm manners where youll be doing the majority of your street driving. and if you plan to go 7k rpms and up, ditch the hydraulic rollers and go with solids. i wouldnt even consider hydraulics for this type of application. hydraulics do NOT like RPMs, they pump up and cause valvetrain instability and the only drawback in any way to solids is setting valve lash every now and then. valve lash isnt that hard to deal with and can give you easily another 1k in rpms that you can turn without valve float issues. solids for high rpm motors rock.
keep in mind, there is no replacement for displacement and the same setup on a full sized 346ci LS1 would ultimately make for a faster car, but the ability to run a destroked motor like what you're describing would benefit two things in my mind... for one, it would be nice on a track(not a dragstrip) because you could keep the RPM's up all the time with less stress on the motor and have nice top end power with more revs to effectively use before you had to shift. two, it would have a lot of "oh-god-this-is-fun" factor because you could rev the **** out of it and the higher you rapped it up the harder it would pull.
remember that a smaller, destroked motor will create less vaccum inside of the motor so a camshaft and set of heads that does fantastic on a larger, say 346 ci motor would not flow as efficiently(less port velocity) and youll end up with a dog-motor. if you put a fast 92/92 on it with a vindicator camshaft it would be a dog. cubic inches let ya use a bigger cam and intake/heads/headers etc etc and it will still run great everywhere but a smaller motor can be drowned out by those same pieces. youd get owned by every honda in town because youd have to wait for your rpms to get above 4 grand to make any power at all, and by that point you have lost so much ground you're screwed. a 4k stall on the street would suck, too.
a realistically priced destroked motor that would be right up your alley would have some patriot ls6 cnc heads, titanium retainers, a 224-228 cam, fast 78/78 TB or possibly a fast 90/90, some 1 7/8 headers, and a set of eagle or scat lightweight H- beams and lightweight forged pistons to take some weight off the rotating assembly. the intake / TB combo is hard to gauge. id think the fast 90/90 setup might be a bit too much for that, by hurting your lowend torque. at the same time, it could certainly use the larger 90mm setup for higher rpms. and i think an ls6 intake would be fantastic up to 6 grand or 6500, but choke your top end a bit beyond that. its kinda in the middle. id probably try a 78mm fast personally.
a real killer setup of a motor would be some nice TFS 215's or afr 205's with a fast 90/90 combo, an aluminum flywheel, titanium or hollow stem valves, titanium retainers, a 228/230 cam, a nice set of valvesprings, lightweight pistons, titanium or lightweight billet rods, lightweight solid lifters, etc... in essence lighten anything that moves as much as you can. then you have something that performs like a ferrari where when you snap the throttle it raps up like a crotchrocket with instant throttle response and an engine note that screams up to 8 grand or better. big $$$ tho.
port velocity is whatll make your motor fun to drive, with snappy, instant torque and decent low rpm manners where youll be doing the majority of your street driving. and if you plan to go 7k rpms and up, ditch the hydraulic rollers and go with solids. i wouldnt even consider hydraulics for this type of application. hydraulics do NOT like RPMs, they pump up and cause valvetrain instability and the only drawback in any way to solids is setting valve lash every now and then. valve lash isnt that hard to deal with and can give you easily another 1k in rpms that you can turn without valve float issues. solids for high rpm motors rock.
keep in mind, there is no replacement for displacement and the same setup on a full sized 346ci LS1 would ultimately make for a faster car, but the ability to run a destroked motor like what you're describing would benefit two things in my mind... for one, it would be nice on a track(not a dragstrip) because you could keep the RPM's up all the time with less stress on the motor and have nice top end power with more revs to effectively use before you had to shift. two, it would have a lot of "oh-god-this-is-fun" factor because you could rev the **** out of it and the higher you rapped it up the harder it would pull.
remember that a smaller, destroked motor will create less vaccum inside of the motor so a camshaft and set of heads that does fantastic on a larger, say 346 ci motor would not flow as efficiently(less port velocity) and youll end up with a dog-motor. if you put a fast 92/92 on it with a vindicator camshaft it would be a dog. cubic inches let ya use a bigger cam and intake/heads/headers etc etc and it will still run great everywhere but a smaller motor can be drowned out by those same pieces. youd get owned by every honda in town because youd have to wait for your rpms to get above 4 grand to make any power at all, and by that point you have lost so much ground you're screwed. a 4k stall on the street would suck, too.
a realistically priced destroked motor that would be right up your alley would have some patriot ls6 cnc heads, titanium retainers, a 224-228 cam, fast 78/78 TB or possibly a fast 90/90, some 1 7/8 headers, and a set of eagle or scat lightweight H- beams and lightweight forged pistons to take some weight off the rotating assembly. the intake / TB combo is hard to gauge. id think the fast 90/90 setup might be a bit too much for that, by hurting your lowend torque. at the same time, it could certainly use the larger 90mm setup for higher rpms. and i think an ls6 intake would be fantastic up to 6 grand or 6500, but choke your top end a bit beyond that. its kinda in the middle. id probably try a 78mm fast personally.
a real killer setup of a motor would be some nice TFS 215's or afr 205's with a fast 90/90 combo, an aluminum flywheel, titanium or hollow stem valves, titanium retainers, a 228/230 cam, a nice set of valvesprings, lightweight pistons, titanium or lightweight billet rods, lightweight solid lifters, etc... in essence lighten anything that moves as much as you can. then you have something that performs like a ferrari where when you snap the throttle it raps up like a crotchrocket with instant throttle response and an engine note that screams up to 8 grand or better. big $$$ tho.
ok so they used ls6 heads but they didnt go to the big valves like my heads have so im thinkin my ls2 intake which i am cutting apart and doing some epoxie and plastic welding and shortning the runners a little bit for top end and port matching to whichever heads i get---or get a pro products intake which is proven at high rpms with the 78mm inlet because being smaller cubes doesnt need the 90 and a set of ls1 heads that have been ported or 5.3s
03-25-2008, 07:25 AM
#12
I dont think any production or readily available intake is really going to do what you want...even a FAST 92 is going to have trouble keeping up at 8k RPM. For what you want your going to be doing solid lifters, maybe sheetmetal intake, very well built bottom end, etc. do you have a specific goal or racing class in mind? Maybe we can help you reach that goal without spending $20k on a motor 
03-25-2008, 07:46 AM
#13
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i have a daytona prototype internal set
that consists of callies crank 3.185 stroke with 1.888 rod journals
lentz 6.500 rods with carr rod bolts
and jt pistons
same setup the daytona prototypes use
my valve springs will be the same as they use to
that consists of callies crank 3.185 stroke with 1.888 rod journals
lentz 6.500 rods with carr rod bolts
and jt pistons
same setup the daytona prototypes use
my valve springs will be the same as they use to
04-03-2008, 05:55 PM
#14
you can calculate your airflow requirements based on engine size and RPM goals... search for the formula and punch it in to see whether or not a fast intake would support it but I would certainly think so being that you are running a destroked motor. youd have to check to find out.
