Affordable high RPM (7500-8000) motor build based on LS3 crate motor
04-01-2012, 01:02 AM
#1
Teching In
Thread Starter
Join Date: Oct 2006
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Affordable high RPM (7500-8000) motor build based on LS3 crate motor Is it doable to build a reliable LS3 stock stroke race/drift motor from a LS3 crate motor doing only valvetrain/cam/rodbolt + intake/exhaust upgrades?
I'm thinking something along the lines of the following:
GMPP LS3
Holley Hi-Ram intake
102mm throttle body
1/7-8 or 2 inch headers + open 3.5 inch exhaust
Which cam and valvetrain upgrades are recommended for reliability/broad powerband that peaks higher up than what's normal?
Will the bottom end take it, and which rod bolts are recommended?
Will the oil pump take it?
Thanks in advance!
I'm thinking something along the lines of the following:
GMPP LS3
Holley Hi-Ram intake
102mm throttle body
1/7-8 or 2 inch headers + open 3.5 inch exhaust
Which cam and valvetrain upgrades are recommended for reliability/broad powerband that peaks higher up than what's normal?
Will the bottom end take it, and which rod bolts are recommended?
Will the oil pump take it?
Thanks in advance!
04-01-2012, 09:26 PM
#2
TECH Enthusiast
Join Date: May 2008
Posts: 537
Likes: 0
Received 0 Likes
on
0 Posts
I'd be worried about hyper pistons at this rpm level. Drag racing with short time at speed is one thing, drifting or other racing with sustained high rpm is another story.
Considering the cost of the valve train you will likely need, you might want to invest in a fully forged engine. Have you looked at the LSX376? Kind of like an iron block LS3 with forged pistons.
Considering the cost of the valve train you will likely need, you might want to invest in a fully forged engine. Have you looked at the LSX376? Kind of like an iron block LS3 with forged pistons.
04-02-2012, 01:37 AM
#3
Teching In
Thread Starter
Join Date: Oct 2006
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
I'd be worried about hyper pistons at this rpm level. Drag racing with short time at speed is one thing, drifting or other racing with sustained high rpm is another story.
Considering the cost of the valve train you will likely need, you might want to invest in a fully forged engine. Have you looked at the LSX376? Kind of like an iron block LS3 with forged pistons.
Considering the cost of the valve train you will likely need, you might want to invest in a fully forged engine. Have you looked at the LSX376? Kind of like an iron block LS3 with forged pistons.
I'm thinking running a stroker kit inc. forged pistons and H-profile rods (as we can get a good deal on a certain make), but I am more interested in a recommended hydraulic cam/lifter/pushrod/rocker/spring combination with stock valves to be able to run (and make power at) 7500-8000 rpm.
04-02-2012, 08:04 AM
#4
Have you looked at the LSX376? Kind of like an iron block LS3 with forged pistons.
I'm thinking running a stroker kit inc.
04-02-2012, 10:35 AM
#5
12 Second Club
iTrader: (10)
Join Date: Jan 2009
Location: 5.0
Posts: 1,302
Likes: 0
Received 0 Likes
on
0 Posts
id be more worried about heavy forged pistons. forge pistons you need to upgrade the rods.
edit: look for light pistons whether they be forged, hyper, or cast. when looking for rpms and if your N/A, strength is not the priority
edit: look for light pistons whether they be forged, hyper, or cast. when looking for rpms and if your N/A, strength is not the priority
Last edited by disc0monkey; 04-02-2012 at 10:57 AM.
04-02-2012, 12:45 PM
#6
Teching In
Thread Starter
Join Date: Oct 2006
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Guys, thanks for your help, but I am not worried about the bottom end - we will work with our parts supplier to make sure we put together a reliable bottom end for the rpms, whether that is short stroke, long stroke, hypereutectic pistons or not.
What I need help with is speccing a valvetrain and hydraulic cam setup that will work with stock LS3 heads and 7500-8000 rpm. Does anyone have any input on this?
What I need help with is speccing a valvetrain and hydraulic cam setup that will work with stock LS3 heads and 7500-8000 rpm. Does anyone have any input on this?
Trending Topics
04-02-2012, 09:54 PM
#8
First what is your budget... remember this one thing...
( Fast - Reliable - Cheap ) You can only pick 2 out of the 3... If it is Fast and Reliable, It isn't Cheap. If it is Cheap and Reliable it isn't Fast. If it is Fast and Cheap, It isn't Reliable.
Now let talk useable powerband... even with that intake and 2" headers you will more and likely make peak power around 6800-7000 RPM and that is using a rather larger cam. The bottom end is the easy part. Put good quality parts with ARP studs and balanced well in an aluminum block(they are plenty strong!). If it was me... I'd do a short stroke and a large bore. A lot less stress on the rotating assembly and there will be less piston speed. Not to mention you unshroud the valves for more air flow. Forged pistons will be fine. There are ways to cut weight out of pistons since you will not be running any power adders.
Oiling at sustained RPM you need to look at either a 4 or a 5 stage dry sump set up. I wouldn't even consider a wet sump for this application. High G's and high sustained RPMs you would suck the pan dry resulting in spinning bearings.
Now the biggie is going to be a light weight valve train and a solid roller set up. Valve control at that RPM is critical and wont hold up very long with a hyd set up.
Another thing to consider is a ITB set up that way you can adjust where you make peak power at by changing the trumpet length. If you put a longer runner on it, the motor will make peak power at a lower RPM Now, if you have a shorter runner the motor will make peak power at a higher RPM pending your have a cam that will support that RPM and pending there are not restriction in your heads/intake set up. by restriction i mean port volume. This way you can optimize your car for your even based on the track.
Just remember there is no one size fits all. Sit down and talk to knowledgeable people and or sponsors on this forum. Figure out your budget and goals. If you ask vague questions on internet forums where people seem to know it all (hope no one take offense... but if you do, I'm not sorry) You will get pointed in all the wrong directions. My biggest advice is read... read. and read some more. Educate your self and you will make smarter decisions. This will return you with spending less money by only having to do things once.
( Fast - Reliable - Cheap ) You can only pick 2 out of the 3... If it is Fast and Reliable, It isn't Cheap. If it is Cheap and Reliable it isn't Fast. If it is Fast and Cheap, It isn't Reliable.
Now let talk useable powerband... even with that intake and 2" headers you will more and likely make peak power around 6800-7000 RPM and that is using a rather larger cam. The bottom end is the easy part. Put good quality parts with ARP studs and balanced well in an aluminum block(they are plenty strong!). If it was me... I'd do a short stroke and a large bore. A lot less stress on the rotating assembly and there will be less piston speed. Not to mention you unshroud the valves for more air flow. Forged pistons will be fine. There are ways to cut weight out of pistons since you will not be running any power adders.
Oiling at sustained RPM you need to look at either a 4 or a 5 stage dry sump set up. I wouldn't even consider a wet sump for this application. High G's and high sustained RPMs you would suck the pan dry resulting in spinning bearings.
Now the biggie is going to be a light weight valve train and a solid roller set up. Valve control at that RPM is critical and wont hold up very long with a hyd set up.
Another thing to consider is a ITB set up that way you can adjust where you make peak power at by changing the trumpet length. If you put a longer runner on it, the motor will make peak power at a lower RPM Now, if you have a shorter runner the motor will make peak power at a higher RPM pending your have a cam that will support that RPM and pending there are not restriction in your heads/intake set up. by restriction i mean port volume. This way you can optimize your car for your even based on the track.
Just remember there is no one size fits all. Sit down and talk to knowledgeable people and or sponsors on this forum. Figure out your budget and goals. If you ask vague questions on internet forums where people seem to know it all (hope no one take offense... but if you do, I'm not sorry) You will get pointed in all the wrong directions. My biggest advice is read... read. and read some more. Educate your self and you will make smarter decisions. This will return you with spending less money by only having to do things once.
The following users liked this post:
00ps (09-14-2023)
04-08-2012, 08:00 PM
#9
I don't think there have been many good answers here. I'm looking at doing the same thing to a LS3 Dry Sump motor with 2K miles on it I just received from a 2011 Vette. My plan of attack is as follows, the valve train needs help and I'm going with a set of Comp Cams roller trunion upgrade, new stiffer valve springs staying with "Beehive" style using Comp "618" springs/tool steel retainers and hardened valve locks, and push rods are a known weak link in LS motors being revved. The dry sump motor already has a good forged crankshaft, but, I plan to swap in some ARP rod bolts PN 234-6301 which are the 220000PSI "Pro Series" rod bolts. You need to have a good engine builder who knows how to properly torque rod bolts using the stretch gauge method with this series of bolts.
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
04-09-2012, 11:45 AM
#10
Teching In
Thread Starter
Join Date: Oct 2006
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
I don't think there have been many good answers here. I'm looking at doing the same thing to a LS3 Dry Sump motor with 2K miles on it I just received from a 2011 Vette. My plan of attack is as follows, the valve train needs help and I'm going with a set of Comp Cams roller trunion upgrade, new stiffer valve springs staying with "Beehive" style using Comp "618" springs/tool steel retainers and hardened valve locks, and push rods are a known weak link in LS motors being revved. The dry sump motor already has a good forged crankshaft, but, I plan to swap in some ARP rod bolts PN 234-6301 which are the 220000PSI "Pro Series" rod bolts. You need to have a good engine builder who knows how to properly torque rod bolts using the stretch gauge method with this series of bolts.
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
Why exactly is it that the bottom end won't cope with mid 7000 to 8000 rpm with proper rod bolts? Is it oil pump, bearings, rods, piston or the crank itself? Will a 4 inch forged stroker kit handle that rpm? It certainly seems to work in the LS7.
04-11-2012, 03:28 AM
#11
Connecting rods are heavy and despite what GM and others say about the technology, the powdered metal technology isn't that great (have seen them crack due to stress in LT1 gen2 motors and in HD truck applications.) Cast pistons not suitable for high speed use, if you were drag racing you might get away with it but, not at sustained high RPM use. Use your LS3 as a trial test bed to get chassis dialed in then upgrade shortblock to better specifications at later date.
The following users liked this post:
my406cid (03-31-2021)
04-11-2012, 07:42 AM
#12
I don't think there have been many good answers here. I'm looking at doing the same thing to a LS3 Dry Sump motor with 2K miles on it I just received from a 2011 Vette. My plan of attack is as follows, the valve train needs help and I'm going with a set of Comp Cams roller trunion upgrade, new stiffer valve springs staying with "Beehive" style using Comp "618" springs/tool steel retainers and hardened valve locks, and push rods are a known weak link in LS motors being revved. The dry sump motor already has a good forged crankshaft, but, I plan to swap in some ARP rod bolts PN 234-6301 which are the 220000PSI "Pro Series" rod bolts. You need to have a good engine builder who knows how to properly torque rod bolts using the stretch gauge method with this series of bolts.
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
I'm going to run a Comp custom grind we picked out of their XFI RPM series of lobes, and this motor will be used for autocross time trials and hopefully at Good Guys events. The 2 big known weak links in LS series motors are push rods, and connecting rod bolts. The parts swapping is running an additional $1200 to my motor swap and I see it as a cheap form of insurance for my intended useage.
If your swapping camshafts, you need to check valve to piston AND valve lock to stem seal clearances, most times you have to change your valve stem seals to different type for cams with bigger lifts (0.580-0.620 lifts.) Also I hope your motor is a true LS3 and not a L92 as the valve weights on the LS3 are lighter than the L92 motors.
I dont think the mid 7000-8000RPM range is doable with stock bottom end but up to 7200RPM my changes should work well. Hope this is some help to you
04-11-2012, 03:00 PM
#13
TECH Regular
Join Date: Nov 2010
Location: Your GF's pants
Posts: 443
Likes: 0
Received 0 Likes
on
0 Posts
To be honest I'd take a totally different route than what you're thinking.
A solid roller, dry sump, high compression 4.8litre. Put the best possible heads you can afford on it, and a hefty cam (suited for the cubes, as overcamming is not a good thing.)
A solid roller, dry sump, high compression 4.8litre. Put the best possible heads you can afford on it, and a hefty cam (suited for the cubes, as overcamming is not a good thing.)
04-11-2012, 09:31 PM
#15
Registered User
Join Date: Mar 2012
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
I've been daydreaming about something similar. I want a motor that will spin to those revs, at least 7000 on a regular basis with the ability to over-rev to 8000 at times.
What about a 4.8L crank in a 6 liter block? By my math it would be virtually identical to the Gen 1 327 (328.5 to be exact) and should rev well I think. Does anyone know if this has been done before? If you used the LS3 valves, solid rollers and forged con-rods I think that could be a potent combination.
What about a 4.8L crank in a 6 liter block? By my math it would be virtually identical to the Gen 1 327 (328.5 to be exact) and should rev well I think. Does anyone know if this has been done before? If you used the LS3 valves, solid rollers and forged con-rods I think that could be a potent combination.
06-15-2014, 07:13 PM
#17
Sorry to bring thread up from the dead but I'm trying to do this myself with a 2013 ls3 camaro ss motor..
so i understand i need to do the trunnion to handle over stock rpm.. ok ordering those parts. and from what 427ze06 wrote i need stiffer "beehive" style comp valve springs 618's w/ steel retainers and hardened valve locks. ok so i understand that..
what i don't understand and have specific part number for is better push rods. which brand and part number push rods handle the abuse better then stock?
I'm looking into a cam but have no idea what cam will work with stock stroke and bottom end?
any help guys
so i understand i need to do the trunnion to handle over stock rpm.. ok ordering those parts. and from what 427ze06 wrote i need stiffer "beehive" style comp valve springs 618's w/ steel retainers and hardened valve locks. ok so i understand that..
what i don't understand and have specific part number for is better push rods. which brand and part number push rods handle the abuse better then stock?
I'm looking into a cam but have no idea what cam will work with stock stroke and bottom end?
any help guys
06-16-2014, 07:01 PM
#18
TECH Fanatic
iTrader: (10)
Join Date: Mar 2011
Location: Miami gardens FL 33055
Posts: 1,023
Likes: 0
Received 0 Likes
on
0 Posts
My take... Have a build on based on personal experience that will (rev fast) and high
with low maintenance using LS power.
Is especial in that will not give up normal drivability for high RPM capability sense is employing around 416 Ci .
It will make 800 crankshaft horsepower @ 7,500 rpm with power across the chart from 3,500 rpm.
The build will take you in a different direction than you have in mind but is true at 7,500 making such power the rpm will sound more like ten thousands.
These build will outperform same car same weight making 200 hp more in just about any other configuration those dubbed (rev fast)
Will cost more than your crate start.
with low maintenance using LS power.
Is especial in that will not give up normal drivability for high RPM capability sense is employing around 416 Ci .
It will make 800 crankshaft horsepower @ 7,500 rpm with power across the chart from 3,500 rpm.
The build will take you in a different direction than you have in mind but is true at 7,500 making such power the rpm will sound more like ten thousands.
These build will outperform same car same weight making 200 hp more in just about any other configuration those dubbed (rev fast)
Will cost more than your crate start.
06-18-2014, 10:36 PM
#19
Sorry to bring thread up from the dead but I'm trying to do this myself with a 2013 ls3 camaro ss motor..
so i understand i need to do the trunnion to handle over stock rpm.. ok ordering those parts. and from what 427ze06 wrote i need stiffer "beehive" style comp valve springs 618's w/ steel retainers and hardened valve locks. ok so i understand that..
what i don't understand and have specific part number for is better push rods. which brand and part number push rods handle the abuse better then stock?
I'm looking into a cam but have no idea what cam will work with stock stroke and bottom end?
any help guys
so i understand i need to do the trunnion to handle over stock rpm.. ok ordering those parts. and from what 427ze06 wrote i need stiffer "beehive" style comp valve springs 618's w/ steel retainers and hardened valve locks. ok so i understand that..
what i don't understand and have specific part number for is better push rods. which brand and part number push rods handle the abuse better then stock?
I'm looking into a cam but have no idea what cam will work with stock stroke and bottom end?
any help guys
04-01-2015, 01:01 AM
#20
Im making 796w 840tq on 9psi boost 6500 limiter.. forged pistons rods katech torquer cam w push rods to match ti valve seats n guides single high psi springs..
my tuner n i want to be about to safely rev 7000-7500 since car is still making power at limiter... how can i do this safely... I'm looking to get new stock stroke forged crank.. just need supporting head mods to accomplish 7-7500k rpm...
can you help me with the information please.. thanks A LOT
my tuner n i want to be about to safely rev 7000-7500 since car is still making power at limiter... how can i do this safely... I'm looking to get new stock stroke forged crank.. just need supporting head mods to accomplish 7-7500k rpm...
can you help me with the information please.. thanks A LOT