I am running a 5.3 aluminum block with stock bottom end, and stock heads. Behind it, is a manual transmission. Oiling is addressed already with a baffled pan, as well as an accusump. I am planning to choose a cam, and lifter springs for this engine, but since my goal is more than just make as much power as possible I don't know how to select a cam. I expect to keep revs down so as to not turn the engine inside out. so what is a good rev limit? I want as much power as possible, without sacrificing longevity. I'm am interested in your thoughts.
Apparently the ASA spec engine never had a valve train failure. You can buy the cam. I've got it in an LS3 and it's got a great character with a usefulspread of power. Same cam is in the Miata that's done well in the enduro racing scene out east for years.
I would think just going to an LS6 cam might give you what you need with a 5.3. What intake manifold are you running? Upgrading the springs/rockers/pushrods? Headers?
Not endurance racing but lots of track time. A friend of mine has an L33 in his 2nd gen RX-7. Stock L33, ported LS6 intake, ls6/ls2 valve springs, baffled pan, comp trunion upgrade, and hardened pushrods. Stock heads and cam. Idea was to reliability, keep power and rpm down for the class while making good torque. No motor failures. The ford T5 even lived behind it pretty well until he went to hoosiers.
I don't run an LS, but have been heavily in endurance racing for a really long time. Tons of LS swaps. Keep it cool, keep it oiled. I believe the 5.3 LS redlines at 6k. I'd shift at 5k. Yeah, you may give up .5 sec per lap. However, it's an endurance race. If you want it to last 15 total hours, show it mercy. The 6M in the Cressida I race redlines around 6500 I think, but I shift between 5000-5500. We finish top 10 each and every time unless we have an issue (not engine related most of the time).
Prime example. Just a few months ago at New Hampshire. Out of 120 cars, we had the 25th fastest lap overall, yet finished 6th overall and won our class. We started 7 laps down as a "penalty" for being in class B, and had a power steering belt jump off, which took about 7 minutes of track time. Had we started even and not had the belt come off, we'd have finished 4th or 3rd overall.
As I said, keep the engine oiled and cooled. Show it mercy. You don't need to go nuts with any power upgrades. Key to success...
Watching to learn.
What kind of baffled pan are you using?
SKJSS (formerly Klayfish) said:
I don't run an LS, but have been heavily in endurance racing for a really long time. Tons of LS swaps. Keep it cool, keep it oiled. I believe the 5.3 LS redlines at 6k. I'd shift at 5k. Yeah, you may give up .5 sec per lap. However, it's an endurance race. If you want it to last 15 total hours, show it mercy. The 6M in the Cressida I race redlines around 6500 I think, but I shift between 5000-5500. We finish top 10 each and every time unless we have an issue (not engine related most of the time).
Prime example. Just a few months ago at New Hampshire. Out of 120 cars, we had the 25th fastest lap overall, yet finished 6th overall and won our class. We started 7 laps down as a "penalty" for being in class B, and had a power steering belt jump off, which took about 7 minutes of track time. Had we started even and not had the belt come off, we'd have finished 4th or 3rd overall.
As I said, keep the engine oiled and cooled. Show it mercy. You don't need to go nuts with any power upgrades. Key to success...
This - our Honda engine can rev out and make power all the way to 8500. I have a hard redline at 7200 through the tuning software to ensure it stays together.
I have the Holley pan, and their baffles . Truck intake. I'm planning on doing valve springs when I choose a cam.
It's 100 points to run a dry sump if I remember correctly. But those are the first points I'd take.
Tires make such a major difference in lap times but they put such a demand on the oiling system. A used dry sump probably costs the same as baffles and a surge pump. But the long term results are worth 10 times the cost.
If you e never driven a race car with a dry sump you should. No power gained just durability. That surge pump needs to be refilled and it automatically is. Just the moment pressure drops and the demand starts.
No priority to anything. Nope it doesn't wait until demand slows down it sucks oil into it as soon as space becomes available.
Right when bearings need oil. But hey the gauge shows pressure.
I raced for 40 years. And then it raced for another 5. On the original bearings thanks to the dry sump.
The way a dry sump works is used oil is sucked from various places on the engine put in a tank that swirls air out and then it fills the bottom of a tapered tank. Air free, clean, cool, oil goes into the pump regardless of everything.
That.'a what provides durability. Not a band aid approach that makes you feel good.
Regarding camshafts. There are a lot of "experts" will to give you free advice. It's worth what you paid for it.
Find out yourself. There are engine analyzer programs that will actually tell you what works in your application.
You need to know how much your heads flow in order to get the right one. There are some numbers out there for some stock heads. Lacking anything else you can use them but that's putting trust in people you don't know. Or what their agenda is. It doesn't cost much or take much time.
If you put your flow bench numbers in, don't be surprised if the stock cam is actually the best. Chevy engineers are smart and understand trade offs.
The worst thing you can do is over-cam an engine. You trade off power every place except peak power. Yeh it's a bragging rights thing. I gained 100 horsepower. My laps are slower for some reason.
Put real numbers into the computer and a stock engine with a stock cam will typically beat a stock engine with an aftermarket camshaft.
Look more at the torque curve than the horsepower number.
I restored a race car but stock a stock Target master in it. That year I won 12 or 13 races.
When he started racing he'd rev the engine until the valves were floating. Then shift etc. with the same car he'd rarely finish in the top 10 and sixth was his best.
that's not me being.a great driver, it's just me using what it had.
Midway through the season he had me building him more powerful engines. I eventually built him a 430 cu in small block that parts alone I had $17,000 in it.
Each more powerful engine put him further back in the field. Yes they were dyno'd to ensure everything was right.
frenchyd said:
Regarding camshafts. There are a lot of "experts" will to give you free advice. It's worth what you paid for it.
Find out yourself. There are engine analyzer programs that will actually tell you what works in your application.
You need to know how much your heads flow in order to get the right one. There are some numbers out there for some stock heads. Lacking anything else you can use them but that's putting trust in people you don't know. Or what their agenda is. It doesn't cost much or take much time.
If you put your flow bench numbers in, don't be surprised if the stock cam is actually the best. Chevy engineers are smart and understand trade offs.
The worst thing you can do is over-cam an engine. You trade off power every place except peak power. Yeh it's a bragging rights thing. I gained 100 horsepower. My laps are slower for some reason.
Put real numbers into the computer and a stock engine with a stock cam will typically beat a stock engine with an aftermarket camshaft.
Look more at the torque curve than the horsepower number.
I restored a race car but stock a stock Target master in it. That year I won 12 or 13 races.
When he started racing he'd rev the engine until the valves were floating. Then shift etc. with the same car he'd rarely finish in the top 10 and sixth was his best.
that's not me being.a great driver, it's just me using what it had.
Midway through the season he had me building him more powerful engines. I eventually built him a 430 cu in small block that parts alone I had $17,000 in it.
Each more powerful engine put him further back in the field. Yes they were dyno'd to ensure everything was right.
Yeah regardless if your road racing or oval or drag racing driver style is important. One style works for one driver won't work for the other driver. Some need to be more aggressive some need to be much smoother. That comes down also to how much power and where the power is made too. Some drivers will do better with a engine with more low end while others do better with more top end. Plus anytime you add power be it low end or top end u need to make sure your set up is right for the combo. You can't run a low power handling set up with a more powerful engine. I've seen people in dirt late models run better with a much lower power modified engine in their late model then they did after getting a proper late model engine. That was due to to the set up and handling.
With camshaft in endurance racing the key will be reliably so I think you would want to stay at stock or close to stock duration and look at at torque and keeping revs down. Why do you think the c5r and c6r 7 litre engine was such a good endurance engine because they could make plenty of power and torque at lower rpms. Plus if you don't want to run stock cams lots of manufacturers make aftermarket cans at stock or close to stock duration.
The LS valvetrain can get a bad rap from the guys that want +.630" of lift, 280 degrees of duration and 8000 rpm. Keep the lift under .550" , don't over do it on the spring pressures and keep the revs under 7000 rpm. You shouldn't have any issues and will have a very healthy V8.
Honestly, I think you're going to go down a rabbit hole you wish you never had. Make it reliable and send it.
I would keep it mild-ish. Are you running a factory ECM with knock sensors? If so, keep them.
LS6 heads (243s) are a good bet. If you want to spend the coin, Advance Induction has a stage 3 full CNC porting that is amazing. It doesn't add a lot of volume to the ports, but they flow incredibly well. That lets you select a cam in the middle so you don't kill low end, but it will reach 6500 without wheezing. I went with a 234/227 grind on a 113 LSA for my LQ9 with LS6 fully ported heads. I would love to tell you it works great, but I haven't fired it yet. It is, however a known combination that makes just around 500hp and maintains more than enough low end torque for a light car.
As far as intake, it's super hard to beat the truck intake. Equal to or better than the LS6 intake. Ugly as berkeley, but works great.
One caveat... I'm not an endurance racer. The LS I mentioned above is for a street monster that I can take on a roadtrip. I fully intend to put 100k trouble free miles on it.
I had Bobby at Cam Motion spec my new cam with longevity in mind for track use. I think we ended up with .615" lift, down from the .650" I was running before. I'd also look into replacing the oil pump and making sure it's shimmed correctly. Just a standard pressure/volume Melling pump will be fine. Also do the rocker trunion upgrade.
RacetruckRon said:
The LS valvetrain can get a bad rap from the guys that want +.630" of lift, 280 degrees of duration and 8000 rpm. Keep the lift under .550" , don't over do it on the spring pressures and keep the revs under 7000 rpm. You shouldn't have any issues and will have a very healthy V8.
That's why I was recommending the ASA cam. Works with stock LS3 or LS7 springs and is well proven in competition with a couple of decades of history. It gets talked down by the dyno tuning heroes because it doesn't have crazy lift or make 600 hp and it can be a little cranky on a street car, but it's got that history of reliability behind it. I'd trust that over the flavor of the month.
MotorsportsGordon said:
With camshaft in endurance racing the key will be reliably so I think you would want to stay at stock or close to stock duration and look at at torque and keeping revs down. Why do you think the c5r and c6r 7 litre engine was such a good endurance engine because they could make plenty of power and torque at lower rpms. Plus if you don't want to run stock cams lots of manufacturers make aftermarket cans at stock or close to stock duration.
Lift is the killer to longevity, not duration. More lift requires more aggressive ramps profiles in most cases which slams the valve closed. You also need more spring pressure to cope with more lift with also adds more stress to all the parts involved.
Patientzero said:
MotorsportsGordon said:
With camshaft in endurance racing the key will be reliably so I think you would want to stay at stock or close to stock duration and look at at torque and keeping revs down. Why do you think the c5r and c6r 7 litre engine was such a good endurance engine because they could make plenty of power and torque at lower rpms. Plus if you don't want to run stock cams lots of manufacturers make aftermarket cans at stock or close to stock duration.
Lift is the killer to longevity, not duration. More lift requires more aggressive ramps profiles in most cases which slams the valve closed. You also need more spring pressure to cope with more lift with also adds more stress to all the parts involved.
My bad I get those mixed either way id keep it at stock or similar to stock. It's silly to build a high reving engine for endurance racing especially since this won't be imsa etc. And even then it's not like they rev them particularly high in modern pro endurance racing. All the engines wouldn't survive otherwise .
Let's look at it this way the car that got banned from the scca pro endurance show room stock series after winning every race was the c4 corvette with the l98 which wasn't a particularly high reving engines as it made its torque at 2800 rpm.
Guys with the aftermarket needle bearing rocker trunnion kits--are you doing used oil analysis? If not, you should pop one of those rockers apart and check the trunnion for wear.
I did a UOA on an engine 8k miles after installing one of those kits and iron and chromium came back high. I eventually figured out the rocker "upgrade" kit was the source. When I took the rockers apart, it was clear that the aftermarket trunnions weren't hardened enough, and the needle bearings were eating them.
I went back to stock rockers, no more problems. Sometimes you can't beat the OEM.
GM probably has a higher development budget for the LS than the entire aftermarket put together, and they have to offer a warranty.
In endurance racing, I love a motor with drivability. I raced a '96 Miata in several races in Texas at the same track. The first few races it had the 1.8 Miata motor, then they swapped to a 2.4 Ecotec.
The fist few races with the stock Ecotec were the best times I did there. Most laps I could easily do in fourth gear only, as it made good torque, especially compared to the 1.8L. The last race, he took the balance shafts out, and played with the tune, which moved the power band up. It made the car slower, as the drivability went away. Now I had to use third a lot, even with no traffic around. The slave cylinder failed during the race too.
When endurance racing, I'm all in favor of making it as easy on the driver as possible. I see plenty of people pass me early on, wheels at opposite lock, with their hands full. An hour later, after a few offs, they're going slower, and sometimes with damage.
A good power band, with useable power out of slow corners is more desirable to me than peak power.
In reply to racerfink :
I was a mechanic on the Mazda race team for the 2006 Thunderhill 25. We were running the brand new NC Cup Car prototype, and it became apparent that the transmissions were good for 200 laps before they broke a shift fork. So we patched up the cars and told the drivers to stay in 4th after that.
Fastest time of the race (for one of our cars) was set at 3 am by a driver only using one gear - although I suspect he might have slipped it into 5th on the back straight. Still, it was smooth and zen and in the zone instead of trying to drive the wheels off the car.
MotorsportsGordon said:
Let's look at it this way the car that got banned from the scca pro endurance show room stock series after winning every race was the c4 corvette with the l98 which wasn't a particularly high reving engines as it made its torque at 2800 rpm.
Yeah, that engine made all the torques all the time. I put a cam and short ram intake on an L98 wih bigger injectors and damn.... 300+flbs from 1500-5000rpm. That's an engine that cares not what gear you use.
