WHAT IS A TOWING CAM? LET'S TALK TECH
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- เผยแพร่เมื่อ 23 มี.ค. 2024
- WHAT IS YOUR DEFINITION OF A TOWING CAM? DOES IT MAKE MORE TORQUE? IS THAT MORE PEAK TORQUE? MORE LOW-SPEED TORQUE (AT WHAT RPM?) DO YOU CARE ABOUT MAKING LESS HP? IS THE DEFINITION OF A TOWING CAM SUBJECTIVE?
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When I was a long haul truck driver the engine was designed to make a certain amount of torque and horsepower at a specified rpm range and then it was all on the transmission gearing and the final drive gear ratio to keep the motor in the optimal rpm range. My point is I think a lot of people don't consider proper gearing to capitalize on peak rpm range. But I'm just a old hillbilly truck driver with a passion for performance.
Gears for the win.
Water injection, more compression, more ignition timing, early intake valve closing. Remember old magazine ads saying water injection works great when towing. DV recently did episode on water injection.
Who's DV?
Dave vizard
Thanks for all of your awesome work!
I think I'm kinda your typical outdoors guy. I tow campers, boats, trailers with lumber or steel, cars, etc. Having said that, I live in Western Montana, so there is very little flat towing. I find myself ALWAYS putting my foot to the floor. I understand the whole "RV" cam concept, but it seems I'm always wishing for more power, especially if the truck kicks down. It seems I'm in the over 3k rpm; usu from 3k to 5k range. Once, I towed a full 20ft conex from AZ in my 6l silverado. I basically left the truck in 2nd gear and tachd 4500 rpms all the way home. Every time I tried to let it shift, the truck would slow down and kick back into 2nd. Haha, I ended up smoking an exhaust valve and broke a valve spring. So, I am glad you "get it" in terms of real-life small truck towing. My present everything rig is a 2002 2500hd chevy. Since it's my everything rig, and it is cold here, I chose a gas 6l. Many of my friends with diesels have problems all winter long. Especially, when we are out hunting and you can't plug in the truck. I had a truck w a roller cam 454, but as you know, the gas mileage is almost the same towing or not. Anyway, I haven't built it yet, but have a 408 stroker kit. Based on your tests I will buy either truck norris or choppacabra, (whatever I can get), trailblazer intake, and am undecided on heads.
With the increased displacement, would I need to increase valve size in the stock heads? And would it "marginally" raise the effective compression? Also, since I live at about 6k ft, I am thinking of increasing the compression. Would a 243 head allow me to run regular when not towing?
People don't seem to know that the factory specs these cams out for everyday use, smooth idle,and power at low RPMs. It doesn't cost a manufacturer any more money to make whatever cam they decide on. A rear end gear change is probably your best bet if you need more power towing.
I believe richard when he says long runner for lower rpm power. I can't figure out why people that sale intakes say the longer runner is for hi rpm🤔
A lot of people like myself are sort of looking for something dual purpose. When I built my most recent 454 I installed the Comp Extreme Marine 226/236 grind. I didn't want it to run out of breathe immediately but did want it to make decent torque under the curve for when it does tow. I also knew that the real heavy towing will be with my diesel service truck. This truck needs to tow a small camper, car trailer, etc. Not be pushing the limits of no CDL with a pickup. lol
I really liked this conversation. When towing, I need all the power in the entire RPM band. I have a 2012 Silverado 1500 Crew Cab 4WD Z71 with the 5.3 L LC9 all aluminum V8 with VVT and AFM (disabled). I have a K&N Intake with a Flowmaster exhaust and a Hypertech tune for the most power out of the stock engine. Maybe I've boosted the 315 HP to about 330 HP at the crank. My truck has a 6L80 transmission and 3.42 gears with the stock tire size 31.5" tall tires.
As Richard talked about towing up mountain grades to get the the destination that is so true. When I tow my 25ft travel trailer that weighs a max 6,000 lbs up mountain passes, it needs all the power from the LS v8 under the hood of my truck. One particular mountain grade is about 7 miles long in a 40 mph zone with an elevation gain of nearly 3,000 ft. in Fairview Canyon in Sanpete County, Utah up to Skyline Drive. My engine would scream up to redline in first gear and then shift to second gear and bog at low RPM, then downshift back to first gear and scream while at WOT the entire way up the mountain. Trans temp and engine temp would rise, but not to a dangerous level. I could go a max speed of 25-35 MPH up that mountain pass at WOT. The VVT and stock cam was doing all it could for my little 5.3 L LC9 V8. I'm not sure if a Truck Norris cam would help in this situation. Maybe it could.
I'm in the same situation. I have a huge mountain pass at my door. My one ton truck has 4.56, but I'm limited with a th400 and barely 200hp. I need more engine.
@@xmo552 Or boost.... cheap nasty boost
The 400m had a really good rod stroke ratio for low to mid rpm range. The block is tall enough to take a 4" stroke, but it wasn't great about passing a gas pump! Frankly, a towing application you shouldn't be worried about anymore past 4500rpm! Feel free to disagree, but, I tow campers and large boats!
Yeah, it just needed quench. Even 4v quench heads with the stock intake manifold, and the 4V exhaust manifolds. Simple change, huge difference. Add a beast cam, (206/212) go forth and rejoice.
Always enjoy listening to your lessons. Keep it up. Best on youtube.
My friend ran an RV cam for years in his big block 455 Oldsmobile 442 he ran 12.40s shifting at 4500 rpms. He raced 🏁 it for 20 year. He tried shifting it at higher rpms but it went slower
On the Ram trucks with the 6.4L intakes added as well( lots of gains everywhere in the rpm range) most guys stay below
210/XXX on the cams for the low end power. And with the gearing of the 8Hp70 even 3.21 rear end gears work very well. However, 3.55-3.92’s will do wonders.
Also, we’ve found that anything above a 2,600 stall creates a lot of heat.
I can only hope nobody is towing in overdrive, so less likely to be near 2000 rpms.
***Unless the trailer is empty etc.
Towing cam needs to be happy in the 2500-3200 rpm range. Crane use to advertise their cams in recommended “Cruise RPM” ranges. Erson Cams may have too? 🤔
Stock LS cams are off idle to 4500 rpms, intended shift set at 5200 rpm.
So, a cam with a slightly tighter LSA to help build cylinder pressure, (accounting for detonation), as our limiting factor in the 2200-5500+ rpm should be an improvement.
I know that the Bbody LT1 camshaft makes much more torque than the Fbody or Vette versions and less HP. Power wise the only difference is the aluminum heads. The iron heads actually flow better ironically and the combustion chamber is moreless same size
I'm not a mechanical guru, but if I were going to turn my already torque heavy Sierra into a tow rig. Since I already have a trans cooler, I'd probably start with a small turbo.
When I have hauled with it. It did fine, except on steep grades.
In my semi, that's when the turbo kicks in, and I easily climb to the top (unless I'm hauling almost 80k lbs. of Brembo brake rotors through the mountains from Homer, MI to Ford in Lexington, KY).
Honestly, most 3/4 and 1 tons from any of the Big 3 have enough torque to haul. So if you don't have a trans cooler. That's the first place you should consider putting some money! Second place would be a turbo.
I remember years ago, it was thought that maximum power with the intake lobe centerline matching the lobe separation, but it was also known that advancing the cam would increase cylinder pressure. Later, late 70's, early 80's, that maximum horsepower was thought to be with the the intake lobe centerline at 106 regardless of lobe separation and maximum torque was with the intake lobe centerline at 102 degrees.
look at valve events
If you’re towing with your truck more than 60% of the time. Upgrade to a 2500 with the 8.1 you’ll be very satisfied with that.
I believe if you have a lockup converter it should be a 3k stall even with a stock cam. If it's a 3 speed it still needs a 3k stall but it needs to be a well built 3k that's not really loose. Generally I run 3k 3500 stall on everything and I've never been disappointed. Also with a silveraldo (4 speed older trucks) should all have 4.10 minimum gears from the factory
A cam that keep’s catalytic converters cool that’s a towing cam I have seen cat overheat kick in often with a lot of overlap
Your comprehension level is 🤯
Considering my stock 2500HD pulls Mtn passes at 4500 rpm in 2nd gear with a 28' trailer, i'd think any cam that improves between 3-5k rpm would be a good rv cam.....for me
Same. I'm towing a camper with a 5.7 mated to a 400 transmission in a square body 2500 4X4 suburban. 7.7 mpg. 😱
@@pocketPliers
Yup. Agreed.
81 GMC c3500 350/400/4.56
I need more gearing and a little more power.
I'm running a similar setup currently- 2500hd crew cab 6.0L/NV4500/4wd. I tow a ~5000lbs trailer occasionally. When pulling a hill I let it turn 3000-4500 rpm.
I plan on building a 402 stroker for it w/ ~9.7-10.0 compression and mildly ported heads. Cam will be either truck Norris or a summit 205/212.
Ive got a 2500hd 6.0 and pull a 32” toy hauler and I installed a cold air intake and flowmaster exhaust and Im pulling the same hills over 20mph faster
This is why I tow with a dodge diesel, gobs of power above about 1700 rpm and on the downside not much above 3500.
If I had to do it with gas it would be a huge inch motor with deep gears and a little supercharger ,small cam to mimic diesel
This is an interesting topic. I recently rebuilt the FE 360 in my 1975 F100 and did a budget build / overhaul and stroked it to 390 cubic inches. swapped out the 2 bbl intake to a cast iron 4bbl intake / 650 vacuum secondary carb and long tube headers. I spent a lot of time on forums looking for real world info from people that had done a similar build and camshaft recommendations. I ended up buying a comp 260H 212/212 duration, 110 lobe separation based on the fact its supposed to be a truck cam and make most of its power in the midrange. I would be super interested to know how the 260H compares to the stock cam in terms of horsepower and torque curve. I would have to step on it pretty hard to get the C6 to kick down to second gear on the highway, so its a bit different than a modern truck that can drop 2 or 3 gears to get the RPM way up. With these old school rigs I think you are aiming to make the Highest possible torque at the RPM the motor is turning on the highway which is usually pretty high depending on rear end ratio, well over 2000 without an overdrive.
Forgot to mention that I kept the stock 360 truck pistons with 390 crank and rods and that brings the pistons higher up in the hole which I think adds about a full point of compression ratio.
Vacuum =towing most cams with -9 overlap are a good for towing also a cam that can pull soon in the rpm not want to rev to the moon before full power kicked in also a cam that keep’s catalytic converters cool
My thought is that most cams are lift starved relative to duration. Old "tow cam" grinds typically have terrible lift numbers and a short duration. Now, if your cylinder head is good, you can add .05 or .10 lift with little or no difference in reliability, drivability, and get significant gains. Really, a "TOW" cam is just a cam that has close to normal drivability on a stock driveline. To me, a good tow cam grind is a hyd roller 212/216 @ .05, and has .550/.560 lift, on 325 to 400 ci apps, and again, this is for people trying not to alter the driveline.
we tested the effect of just lift-not much there. The NSR TN cam had 500 lift, the regular TN had 550 lift-only 6 hp.
@richardholdener1727
Yeah, but as I said, induction quality plays a big part in that, LS Cat ports really aren't there in my opinion nor early G3 Hemis.
Now I know I'm gonna get flamed for saying that, but the gains you get from a later Rec port Ls or 09+ Hemi have the quality I was talking about. If a cam with only 8-10 more degrees, and .05-08" more lift gets you nearly 50hp verified on a chassis dyno, with no really torque loss, well the lift works.
I've always been curious as to why there's nothing that can help down low, because mainly when you take off, they suck... Lol.
But your explanation so far early into this video makes sense that nothing in cam timing or lift/dur is going to help more than stock.
So I guess the next question is, what cam/intake/exh combo would work best for towing purposes with a 5.3? I have the baby 4.8, but the more common engine is the 5.3, so that could be a great test with a draggy. Towing up a hill stock vs a good combo designed for towing, and from a dead stop.
Also, curious when adding a converter to get the engine to start at a higher rpm, does this cause more heat in the trans, and does it hurt fuel mileage as well vs a stock converter?
I'll be honest cubic inches. Gear ratio is the main player though.
A smaller converter in physical size creates more heat, eg 300 mm vs 265mm- the 265 is going to make it hotter, put a transcooler in, a torque cam is ideal for moving heavy loads as you don't need the top end revs anyway, look at the vortec 7400 and 8100 and you will understand.
For 5.3 or 4.8 a TSP Chopacabra or BTR Truck Norris, 862 heads, 6.0+ id say 799/243s and even larger cam. Intake gen 3 or 4 ls intake.
@@johnsheetz6639and not everyone is going to try and find a 454 or 496 big block or can afford a 376 6.2, a 427 7.0 or 454 7.4 LS, they run what they have and the 293/325 have plenty of potential without requiring boost.
Think in terms of a diesels operating range. While a cam may not be the most important component in making a towing situation better there is probably room for improvement. Maybe lower duration than stock with tighter lsa than stock, maybe vary the lift based off of dyno info. An effort to increase dynamic compression down low.
a diesel doesn't make lots of torque because of the cam-it does so from displacement, compression and boost
I was trying to stick to the discussion title
"WHAT IS A TOWING CAM ?
All I did to my 97, 460 was advanced cam 4° pulled like a tractor of idle to 3500
For towing it's really hard to best gearing, for a towing cam look at 2500 to 4500 rpms
I would say a can that makes more power but doesn’t loose any down low.
Mr. Holdener, i have a question that's off topic. Do you have any testing videos on the PCV system?
I have a 7.0 Ford racing engine and i used the PCV system from a 5.0 Mustang engine on it. I recently hurt this engine while street tuning. I think it has a lot to do with PCV being a restriction and causing piston ring flutter in addition to pushing oil everywhere it didn't belong. I'm sure that caused some detonation too.
Thanks in advance.
DO YOU HAVE SUFFICIENT BREATHERS IN THE VALVE COVERS?
@@richardholdener1727 i didn't when before i hurt the engine. I have recently welded (2) -10an fittings to the valve covers, so i add a catch can. I've plugged the OEM PCV port that's in the center rear of the lower intake manifold and removed the check valve. I still have to take the engine apart and see what's damaged.
I have no idea but are they thinking a cam that's "optimized" for low rpm??
Hey, Richard. I was wondering if you have worked with the nissan z series 4 cylinder engines. Specifically the 80s datsun/nissan z24. I'm wanting to put a cam in my 85 720 pickup and was wondering if I would need to change the tappets when changing the cam
if the cam is the same base circle, then no
ELGIN E1257P S running down to 3 gear
Towing Cam = Supercharger.
Have you done this ?
@@xmo552 Yes, many times actually. My towpig rn is 2001 2500 with a 6.0 and a Magnablower and a PDS camshaft
@@woopyass
Ok nice. I asked, because I've been considering blowing my 1 ton Squarebody just for towing purposes. Are you seeing your MPG going down since the supercharger installation?
I've also thought about a turbo so I can tune it to "come on/boost" when I need it. MPG vs power is what I'm looking at.
@xmo552 Yeah of course my MPG went down LOL because that's all it was intended for. I bought the truck to yank the LQ4 and 4L80 to stick in an S10, but it ran too well to just scrap. It had the iron heads so the first chance I had to justify tearing into it, I put some regular 317 aluminum heads, cam and lifters in it with longtubes and a tune, and it was such a great truck to pull things around locally that I started looking for an LSA blower to put on it. I ended up getting a complete wrecked truck with the Magna on it, and put it on the LQ4. After doing a ton of burnouts with it, it just sat around unless I needed to tow my trailer, and I found out that it worked extremely well for that. It pulls my K5 on 1tons so good that I actually sold my dually that I had been using. It's way easier to park and back up without the big hips, and will still smoke the tires with bags of concrete in the bed LOL. I had to add a better water reservoir and an electric pump because the magna setup adds quite a bit of heat to the equation but that wasn't a big deal. That old truck is great the way it's setup. 2001 2500 RCLB LQ4/4L80 2wd 4.11 gears, and the A/C works.
Looking at building a LQ9 mated to a 4L80 to swap into my 90 GMC K2500 with 3.73 gears. I want to build it to tow a little, maybe 5-8k lbs.
Debating 706 vs 317 heads (I have a spare 241 but I don’t think that is beneficial) and on the fence on cam. Looked at Truck Norris or chopacabra but a neighbor also suggested an ASA or ASA clone. Any insight?
706 makes more than 317 (stock to stock), I have cams for sale for $169 if that helps your decision
@@richardholdener1727 any thoughts on the ASA cam? Seems not many videos or dynos on it? Is it just not a popular cam?
Only 15 min into this video but im already finding it very insightful. I have an LS1 catfish thats pretty much stock except a procharger, exhaust, and rear end. Next up i was considering cam and converter. Shes got plenty of go once she gets into boost but i was trying to find a cam that would help down low. From my research, and confirmed through this video, it seems there is no such thing. I always knew cams were a trade off between high end and low end but i always assumed a well made high quality cam could beat out the stock one down low while also raising peak. While true to some extent it doesn't seem to he enough to matter. Torque converter should still help to get me to those higher RPMs/boost quicker but does anyone have any recommendations for what i was trying to achieve with a cam? Aka more torque down low without sacrificing anything up top?
A Truck Norris is better than the LS1 everywhere-and by a significant amount down low compared to that cam
@@richardholdener1727 thanks for the reply. I truly appreciate it. I will start looking into it. There is only one model under that name?
anybody have any thoughts on a cai tbss lq4 with shorties and catback with 9.85 compression ported 317s im trying to figure out what cam i have a 3800 stall tc and mainly drive for fun but do ocasionally have to tow with it and want to stay on 87 octane want a big cam though
with a 3800 stall you can have any cam that will fit the available p-v
the RV cam..?
A good show would be does a "marine/boat" cam make the best TOWING cam..
People used to use boat cams for towing. Constantly loaded motors.
a boat cam and car cam are the same cam
Every cams a boat cam!!!!😂
@@richardholdener1727 so it's all disinformation? Boats live at one rpm. Concentrate power at one rpm.
Like a tow motor. There is no rpm swing under load like an automobile.
In a nutshell my definition would be a low lift but more durations at .500 but I wide LSA for good idle and pulls near stock vacuum
Something that doesn’t come on till big on the big focus on midrange
Consider this Duty cycle A drag engine has a very short duty cycle therefore can get away with lots of compression lots of timing extreme cam profile very limited cooling system ,sometimes no cooling at all By contrast pulling your gooseneck toyhauler/camper up the grapevine requires the exact opposite 100% WOT for miles The factories have had to consider all of this And provide a warranty This is actually very high performance indeed It is not rational to expect just a cam change to offer much improvement A complete engine upgrade---more cubes --more cooling is the answer The heavy duty engines of the 60s worked on about 2 cubic inches per hp I know it doesn't sound like much but you can't have your cake and Edith too
What dose the rule o thumb say about tq?
Maximum amount of torque as low in the rpm range as possible
You didn’t pull stuff in your truck with your 4l60e using overdrive did you? That’s probably what took it out.
Tow mode on adjusts shift points once up to speed you can have OD on, just turn tow back on at a stop to get going. A transcooler goes a long way.
I ran OD and no Tow Mode while cruising down the flat freeway
@@shadowopsairman1583 A 4l60e needs a lot more than a tow mode button/ tune to not be trash.
This coming from someone who currently owns 4 of them. 🤦🏻♂️
Change gears while towing for a camshaft just advance your timing
Do you have any sbc 350 vortec cams
probably
@@richardholdener1727 looking for a truck cam
Low boost non centrifugal supercharger 5-6 psi
Have you done this?
PD BLOWERS WORK WELL
I am interested in a Truck Norris camshaft. I do not have Richard’s email.
In description box of his cams for sale livestream from six days ago.
killerbe16@aol.com
Anything that can help get 50+ mpg
Chevy Spring Turbo
So… you’re saying get a bigger engine. ;)
The best towing cam is a turbo 😂
That's always my choice
Forget fitting a TOW cam , fit a turbo if you want tourqe.
This.
This is the solution I came up with after a few years of contemplating a few different builds.
Gearing whether in the axle, trans, auxiliary trans would help but not in "my" situation.
If I get more engine size, compression, power etc, or supercharger.... all this would cost me MPG AT ALL TIMES.
I feel like a turbo can be tuned to "come on" when I need it most.
Gears …..
Hey Richard I love your videos but when I see there an hour and 13 minutes long I just can't watch for that long
only the live feeds a 1 hour-the others are 10-15 min
Can always fall asleep watching then figure out the next day where you left off .. I do that alot .
Listen in while getting ready for the day
Some of the live stream comments this poor guy has to respond to. 🙄 Clearly not everyone should work on engines. Lol
Why waste a hour to tell us what is a towing cam?
people want to know
Say's who?@@richardholdener1727
All cams are not towing cams .. but they are turbo cams 😁
Why listen to an hour of his bs to tell you what is a towing cam?@@randysullivan5723