Comp's XE Cams

[junkyardhero]

You guys talk about the use of a overdrive transmission, which one, what year?

don't concern yourself with such trivial matters dan. a mild build with reasonable gears won't benefit much from an OD gear.

unless you want to go manual transmission (you don't, won't or can't) the amount of slice and dice needed to shoehorn an automatic one in is a tall order. the price of admission is high no matter the route you take and if you can't do most of that work yourself it can be a nonstarter financially.

but if the weather sucks and you want to read up on it search 518, 500, 42RH or 46RH there's plenty of threads here to lead you down the rabbit hole.

 

[273]

Hi Dan!
Friend;
almost any high lift flat-tappet cam is gonna be "hard" on the stock valvetrain, and often noisy, as compared to the stock parts, which were mostly dead quiet.
How "hard" will depend on how extreme you go, and the willingness of the parts to play nice together, and the level of competency in the assembly of the parts.

The last time we talked, IIRC you just wanted a snappy DD.
At the power-level you were interested in, at that time, this won't be an issue; if the rest of the combo is even just half-decently matched.
In a DD, or in a usage as you described, the absolute power is way less important than having good torque when and where you need it; and to deliver that, with a 318/auto, is gonna be almost entirely dependent on the convertor-stall and gearing.

Absolute power does not happen until all the selected parts come into harmony, which is gonna be an rpm range of about 800rpm, centered somewhere between 4200 of the stock 318 cam, to around 5000 if a cam around factory 340 size. The cams in question here are about 248 to 268 degrees of intake duration, thus a range of 20 degrees. The difference between any two cam sizes is about 7*, so 20 degrees is a range of 3, plus the starting place, so the choices are four, the usual choices being; 248,256,262,268; each cam peaking about 200 rpm higher.
With a stock 318 convertor stalling around 2000 rpm, AND the compression ratio remaining unchanged, and with NO OTHER changes, each cam bigger than 248* is most likely to have LESS take off torque. This means, the power will also be down. The usual cure for this is a higher stall.
The thing is, for a mild 318, and at rpms less than about 2800, each bigger cam is gonna need about 200 rpm more stall just to stay even with the torque of the stock 318.
So even if you keep pace with ever higher stalls, the sub 2800rpm power is hardly keeping pace and the low-rpm performance level is not increasing by much. But at least it's not tanking.
So for a DD that spends most of it's life below 3500; and with only an occasional excursion to maybe 4000, which in Second gear with 2.76s is already over 70 mph; going to a 5000 rpm cam with little or no power increase where you need it below 3500, this is IMO not a good way to go.
The DD needs more power in the operating range that it will be driven in. For a given engine, a bigger cam, by itself, is NOT a good idea. The better idea is to
better match the current engine to the intended application; or, to increase the cylinder pressure, to match the new cam.
Increased cylinder pressure, increases power, EVERYWHERE in the rpm-band.

You posting this like it's a 100% fact, be nice for you to find some dyno evidence to support this, the basic premise is true low cr, bigger cams, smaller displacement, higher gears, low stall all can hurt performance especially low end, but the question is where are the lines and or acceptable compromises, 318willrun 318 duster kind of flys in the face of what your saying his car is basically everything you say not to do.

Now these dyno of 318's don't prove either of us right or wrong since they don't all go down to 2000 rpms so there's guesstimating, first in these 7 examples one being a dead stock 2bbl low cr 318 with headers makes peak torque at 2000 rpm of 292 lbs-ft all the other six make around 340/350 lbs-ft at 3000 rpms with a range of cams from 218 to 247 and all but one with about 10:1 cr, the one that has low cr is the stock long block 318 with 4bbl headers and a comp xe262h. (the ones not shown are the 3 400 hp and 1 425 hp 318 builds)


318 Stock low cr long block with headers vs same with 4bbl and xe262h vs same and carb spacer.

TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPM	BASE	MOD 1	MOD 2
2,000	292
2,500	287
3,000	287	338	336
3,500	272	335	340
4,000	248	326	330
4500	218	309	319
5,000	188	285	296
5,500		250	258

HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPM	BASE	MOD 1	MOD 2
2,000	112
2,500	137
3,000	164	193	192
3,500	182	224	227
4,000	189	248	252
4,500	186	265	274
5,000	179	271	282
5,500		262	270

Now below is a built for the engine master competition but is a 477 hp 318 that makes 337 lbs-ft @ 2500 rpm with a 247 cam and makes the most at 3000 rpm, even if you drop a good percentage off if it's was running stock cr compared to 10:1 cr, reason I post it, it's the only other 318 that shows anything happening under 3000 rpm.

On The Dyno DTS Dyno Data Performance Crankshaft 323CI Small-Block Mopar

RPM	TQ	HP
2,500	337	161
2,600	350	173
2,700	357	183
2,800	357	190
2,900	356	196
3,000	351	201
3,100	345	204
3,200	339	207
3,300	343	216
3,400	356	230
3,500	371	247
3,600	385	264
3,700	396	279
3,800	404	292
3,900	410	305
4,000	415	316
4,100	418	327
4,200	420	336
4,300	422	345
4,400	421	353
4,500	420	360
4,600	421	369
4,700	425	380
4,800	426	390
4,900	427	398
5,000	427	407
5,100	427	414
5,200	426	421
5,300	425	428
5,400	423	435
5,500	421	440
5,600	419	446
5,700	417	453
5,800	415	458
5,900	412	462
6,000	407	465
6,100	401	466
6,200	397	469
6,300	393	471
6,400	390	475
6,500	386	477

Here's something that might help you;
Say your engine makes 265 ftlbs of torque at 2000 rpm, going to 290 @2800. This is a realistic progression.

Actually more like 292 vs 287 lbs-ft

Say you have a 2000 stall and an A904, and 2.76 gears. So then, at take off, not including what is going on inside the convertor, to the rear axles is going;
265 x 2.76 x 2.45= 1792 ftlbs.
Lets say all you did was increase the stall to 2800, and swapped in some 3.23 gears. This gear swap by itself is plus 17% . The new number would be;
290 x 3.23 x 2.45= 2295 ftlbs. This is a total increase of 28%
To get the same result, using the 2000 stall and 2.76 gears, but with a bigger cam;
2295 ftlbs/(2.76 x 2.45) = 339 ftlbs . And 339/265 is plus 28% again. A normally aspirated 318 will never ever make plus 28% at 2000 rpm, with no other changes but the cam. Never! Well unless yur coming back to stock from a way too big cam lol.

The cammed low cr is making 338 lbs-ft at 3000 rpm plus 5 more bigger cammed 318,
The biggest cammed 318 is still making that at 2500 rpm but what do the rest make by 2000 rpm same, more, less, a lot less, enough to kill 2000-2500 rpm performance ?? I Don't really think so, but yes there no proof that they do or don't, guess it's how you guesstimate what's going on there.

I have a hard time believing they all take a huge drastic down turn under 3000 rpm and are being massively smoked by the stock cam at 2000 rpm especially factoring that at 2000 rpm for every loss of 2.7 lbs-ft = only a loss of 1 hp, it would take a loss of 27 lbs-ft (292 vs 265) to kill 10 hp at 2000 rpm (111 vs 101). Not saying that don't matter at all but by 3000 rpm and on the cammed engines are making more hp than the stock does at peak hp, don't you think that has a more dramatic effect on performance?

So then, friend, as I have said before, since, with a bigger cam, you are gonna need gears and a higher stall convertor anyway, you might as well decide on those first, and bolt them up; just maybe, your current engine-combo will be crispy enough for you. It really depends on what is already in your car, and how much hiway driving you intend to do.. For a city car a 2800 and 3.91s is dynomite. That will wake up any old oil-burning smog-era 318, including a 2bbl single exhaust old wheezer. lol Lets say that old wheezer can still make 265 ftlbs @2800; then
265 x 2.45 x 3.91= 2538 to the axles. This is 2538/1792= plus 42%
see what I mean? No cam, by itself, will touch that Plus 42% increase.
Hope this helps

Like usually you'll ignore the possibility that there huge holes in what you're saying and won't readjust in anyway, which Is a shame I like you're basic premise.

 

[rumblefish360]

Oh no! LOL!

Well, you know AJ, if you build to much torque in the engine, you can’t drive it because you’ll just spin the wheels, never get his amazing 37 miles to the gallon nor can you just idle through a parking lot @ 2 mph.

 

[fishmens67]

Oh no! LOL!

Well, you know AJ, if you build to much torque in the engine, you can’t drive it because you’ll just spin the wheels, never get his amazing 37 miles to the gallon nor can you just idle through a parking lot @ 2 mph.

on 87 octane

 

[273]

Even on this video a low cr 360 the xe250h and xe268h cams are doing similar/better than stock cam @ 2500 rpm and up, and yes the two comp cams aren't also taken down to 2000 rpms like stock was but looks like they be in the same general ballpark and yes there's a difference in head work between the stock and comp cams but I don't see huge signs bottom end gonna fall off.

 

[Bewy]

One reason I can think of that more aggressive cams [ such as XE 256/XE268 ] are making more low end tq than a stock 2bbl cam is that the XEs have [a] more lobe lift quicker opening & closing.......which gives [c] more area under the curve.

On the noise from XE flat tappet lobes.

I think Hysteric nailed it. Faster closing rate. However, there could be an additional contributing factor: they have higher lift & more area under the curve compared to other Comp lobes. This requires stronger springs for valve train control. Stronger springs will cause faster lifter bleed down...& that adds to the noise.

 

[AJ/FormS]

As usual you guys missed the point, and missed the qualifiers, and jumped down my back as the all-knowing brow-beaters that you are.
Hopefully Dan got the point.
And one again, just cuz you can't make 32 mpgs with your combo's doesn't mean that it's impossible.
My recipe is out there feel free to copy it.

 

[harrisonm]

I have an XE268 and find it a bit noisy, but I don't mind it.

Just a question as I don't have any personal experience with these cams. Is it true that the xe cams are hard on the valve train because of their aggressive ramps? Also I read / heard that the rocker arms are usually noisy. Again, I'm only asking a question here. What brand cams still have good quality? Lunati, Howard's? I thought that I read that comp was having trouble with the lobes wiping out easily but I don't know this for a fact.

I also have the XE268. It is awesome. It has a nice lope to it, and it really gives the HP. The sound from the exhaust is so sweet, I haven't noticed any valvetrain noise. I have 2.25 exhaust system with two low restriction turbo mufflers. It sounds sweet!

 

[273]

As usual you guys missed the point, and missed the qualifiers, and jumped down my back as the all-knowing brow-beaters that you are.

You one trying to convince even a small cam is gonna kill all performance based on made up torque numbers, not trying to brow-beat ya but you don't think people should do a 318 even in the best of times.

1st there's is plenty of evidence that all these 6 318 builds I'm talking about all smoke the stock one by a huge margin from 3000 rpm and on 80-85% of the full throttle powerband with stock stall. Even at 3000 rpms there's a 50-60+ lbs-ft gain over stock. So that leave 2000 to 3000 rpm with no real dyno evidence, so even if there a huge drop in tq under 3000 rpm not all of is gonna be a loss right at 2999 rpms since there's a gain 50-60+ lbs-ft @ 3000 rpm, so say at worst case 2700 rpms it starts to be less than stock is that 1st 700 rpm (2000/2700) really that more important than the next 2000-3000 rpms plus ? (2700/4700-5700) And that's with a cam that's 20 degrees more than stock what about ones with less?

Not trying to pick on you but people are trying to make decisions $$$$, and there's an obvious hole in your thought experiment.

As for your basic premise stall and gears vs cam swap be an interesting shootout.

 

[Dan the man]

With everyone's experience with cams, what brand would you recommend, lunati, comp cams, Howard's cams?

 

[junkyardhero]

With everyone's experience with cams, what brand would you recommend, lunati, comp cams, Howard's cams?

for me it's entirely application specific. lunati are known for having really great cams for forced induction and power adder applications. comp solid rollers used to be the cats ***. howards makes some really nice old school style grinds with a few modern tweaks and offers them in solid lifter. etx, etx, etx.

and that's if i'm buying an off the shelf piece.

 

[toolmanmike]

Schneider has a bunch of cams listed for Mopar. LA hydraulics, solids and roller. This one looks old school. Low lift, bigger duration, ground on 110°

 

[rumblefish360]

As usual you guys missed the point, and missed the qualifiers, and jumped down my back as the all-knowing brow-beaters that you are.

Ugh! You missed the teasing and yet again, complain about it.
A thicker skin AJ, a thicker skin.

Hopefully Dan got the point.

I think he did. IDK.

With everyone's experience with cams, what brand would you recommend, lunati, comp cams, Howard's cams?

I have found it doesn’t really matter unless you want to slice and dice and subject each cams performance to be tested under a microscope. It’s splitting hairs.

 

[rumblefish360]

on 87 octane

As long as it doesn’t ping!

 

[ir3333]

This stuff is so subjective. You guys talk about strong torque at 2800 in a street car and that's certainly not what i would want. With that in a 318 you need a converter. i have used 3000 stall converter and they are fun but the novelty wears off after a few lo rpm burnouts. Before long i hated driving through the converter on hills and corners. My last build was as good as it gets...for me. Small cam 340 with a stock converter. Lots of torque from 1000 rpm up and pulled very hard below 3500 - 4000 rpm where all street driving occurs.
The problem is too many guys build a quarter mile piece and are very disappointed for daily driving. AJ is correct!

 

[toolmanmike]

This stuff is so subjective. You guys talk about strong torque at 2800 in a street car and that's certainly not what i would want. With that in a 318 you need a converter. i have used 3000 stall converter and they are fun but the novelty wears off after a few lo rpm burnouts. Before long i hated driving through the converter on hills and corners. My last build was as good as it gets...for me. Small cam 340 with a stock converter. Lots of torque from 1000 rpm up and pulled very hard below 3500 - 4000 rpm where all street driving occurs.
The problem is too many guys build a quarter mile piece and are very disappointed for daily driving. AJ is correct!

Exactly. I have been saying it for a long while. Not everybody needs, wants, or can use maximum horsepower.

 

[273]

This stuff is so subjective. You guys talk about strong torque at 2800 in a street car and that's certainly not what i would want. With that in a 318 you need a converter. i have used 3000 stall converter and they are fun but the novelty wears off after a few lo rpm burnouts. Before long i hated driving through the converter on hills and corners. My last build was as good as it gets...for me. Small cam 340 with a stock converter. Lots of torque from 1000 rpm up and pulled very hard below 3500 - 4000 rpm where all street driving occurs.
The problem is too many guys build a quarter mile piece and are very disappointed for daily driving. AJ is correct!

Aj ain't saying small cam he's saying no cam, stock 318 cam only with stall and gears, if you go anything above stock you've murdered the bottom end, and that larger basically only adds on top (totally over looking midrange gain). To me seems a little drastic. I'm not saying stab a big cam in but there are cams that will give gains without screwing up the under 2500 rpms too bad, where's that line is the tricky part.

Like your issue with the converter it's gonna be different for every individual everyone has slightly/vastly different compromises/likes.

 

[rumblefish360]

This stuff is so subjective. You guys talk about strong torque at 2800 in a street car and that's certainly not what i would want. With that in a 318 you need a converter. i have used 3000 stall converter and they are fun but the novelty wears off after a few lo rpm burnouts. Before long i hated driving through the converter on hills and corners. My last build was as good as it gets...for me. Small cam 340 with a stock converter. Lots of torque from 1000 rpm up and pulled very hard below 3500 - 4000 rpm where all street driving occurs.
The problem is too many guys build a quarter mile piece and are very disappointed for daily driving. AJ is correct!

Agreed. Dan did ask about cams and does often. The largest cam I’d suggest for Dan (If he or anyone is asking or wondering) would be a 208@050 as it would not effect off idle performance when ether lightly pressing on the gas pedal or hitting it half way or full way down. The stock converter could be kept and use a 2.76 ratio without issue.

Aj ain't saying small cam he's saying no cam, stock 318 cam only with stall and gears, if you go anything above stock you've murdered the bottom end, and that larger basically only adds on top (totally over looking midrange gain). To me seems a little drastic. I'm not saying stab a big cam in but there are cams that will give gains without screwing up the under 2500 rpms too bad, where's that line is the tricky part.

Like your issue with the converter it's gonna be different for every individual everyone has slightly/vastly different compromises/likes.

Agreed

 

[1971 CY Dodge Dart]

With everyone's experience with cams, what brand would you recommend, lunati, comp cams, Howard's cams?

Hughes Whiplash Cam

 

[toolmanmike]

Aren't Whiplash and Thumper cams just "Poser Cams"? They idle like a top fueler but smooth out like grandma's Rambler at about 2000 rpm or so?

 

[Newbomb Turk]

Aren't Whiplash and Thumper cams just "Poser Cams"? They idle like a top fueler but smooth out like grandma's Rambler at about 2000 rpm or so?

The few of those I’ve been around were pretty respectable. They aren’t bad cams.

 

[michiganpat]

I don't disagree, however tire height can play a factor. With a 27 or 28" tire, you can easily get away with 3.55's. Additionally, a 4 speed, or lock up auto make a difference.

One thing about gearing without OD, it is a game of calculated compromises.

depends on what you're used to. my old 5th ave, when I put 3.55's in with the lockup 904 and 27" tires, I hated it....felt like the engine was strung out, cranking along at 3100-3300RPM at 70-75 on the interstate. I was much happier once I added the 42RH, which dropped freeway cruise to about 2000 RPM at 70. helped fuel economy, and my comp XE262 cammed 360 handled the lower RPM just fine.

my duster has an A833OD with 3.23's and 25" tall tires, and when I go to a big bolt pattern swap, I'm considering a ranger 8.8 axle with 3.08's to get my freeway cruise RPM a little more comfortable, since the OD is only .73 vs. the .69 of the auto.

 

[Dale Davies]

David Vizard states that some cam companies such as Comp.and Lunati offer nitrite hardening for their cams as an option. He recommends taking them up on this for the extra price of $100 as of the writing of his book; How to Build Horsepower. Obviously I would expect this to be more now, like everything else these days. Other than **** and abuse that seems to be freer and more prevalent.

 

[nckennyb]

I put the Comp Cams Magnum Solid lift 270 duration 0.468" lift in my wife's Barracuda and it is a great street/strip cam. It as a little noisy but you expect that with solid lifters, but gobs of torque.

 

[Johnny Dart]

All this back and forth really is a waste of time. Until the guy gets a car, he is just trolling us.