M_Body_Coupe
Well-Known Member
Amazing close to my CompCams piece which is the 112 LSA version of their XR292HR based on 110 LSA!
Torque = Driveability ? (Engine Masters LSA shootout)
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M_Body_Coupe
Well-Known Member
Not quite the match to what you requested above, but...
1) Hughes HE3844AL hydraulic flat tappet in a 360" motor, 596 castings
286/290, 238/244, IO 13, IC 44, EO 53, EC 11, 108 LSA, .536/.540
- Performer RPM, Carter TQ, idle @850, 6-7" vacum
2) CompCams XR292 hydraulic roller in a 408" motor, W2 castings
290/300, 240/248, IO 12, IC 48, EO 60, EC 8, 112 LSA, .584/.580
- Victor 2920 (single plane), Carter TQ, idle @800-850, 9-10" vacum
Car combo: 3600 lbs, 727, 4K stall 9" converter, 4.10 gear, 28" tall tire
The reality of my ride is that it's a seasonal toy, street cruiser and as much as I would love to brag about it being "balls out" at the track, it is not because the chassis is not setup for drag racing, and well, truth be told I make it to the track once or twice a year!
....BUT...BUT...I knew all that before building the 408 W2 stroker combo...and because I wanted a setup that would give me the "least trouble" on the street I opted for the wider LSA.
The results are what I expected and wanted: an easier tune (still not a cakewalk by any means), and that 2" extra of vacum is a WORLD of a difference in a street car!!!
My next cam will probably go a step bigger, so either 246/254, or 250/260 and stay on the 112 LSA because when I hammer that thing I'm already at 4K and the wider LSA is what works well for well flowing heads like the W2s.
Here is a decent article comparing the impact of LSA changes to an otherwise identical cam specs =>
M_Body_Coupe
Well-Known Member
Yup, #1 was the previous combo (but 360 motor) and #2 is the current combo (but 408 motor).
The CompCams roller purchase came about in a weird kind of a way. eBag had it listed for $150 by one of the major parts vendors...I inquired about it and was told that the customer wanted custom LSA (112) but eventually went with another cam altogether, so this one was just eating up shelf space! LOL
I snatched it thinking $150 was a steal for a roller cam, which I still think it was.
I liked the fact that it was on 112 LSA and my thinking at that time was: why the heck do I need that mountain of torque at the bottom end anyways??? I mean car already has 4K stall and 4.10 gearing...gimme a break, like I'll ever miss that 20 ft-lbs below 3000 RPM anyways IN A STREET CAR!!!
Honestly, having a stronger vacum signal at idle and off-idle for the carb mattered so much more to me.
Make no mistake though, given the whole "108 will knock the socks off any larger LSA cam anyday...you will regret your decision...etc...etc" forum feedback I did certainly have my doubts - heck, multiple times. But in the end having previously ran a Crower 112 LSA cam (#31243 - 282-HDP Compu-Pro, 228/238, 282/292, IO 5, IC 41, EO 54, EC 2, .480/.504 on 112 LSA) I was happy to give the wider LSA a chance one more time. I am glad I did.
I came across this old build and found the results interesting and somewhat fits with this discussion, I'm not knocking the build it's a good little engine for what it is and like everyone said in the comments it would scoot very well in a A Body, It's a mild 360 with mildly reworked 318 heads and even a stock 318 cam in one test. Seen it said many times here that should make a torquey 360 which it really don't 350-369 lbs-ft ain't huge numbers for a 360 even at 2500 rpm and even a decent 318 should be capable of similar output (torque & rpms) and even better.
Why I think fits this convo everyone would say this 360 would be very streetable but quite a few would say a 318 with this exact same curve would be a less desirable street engine and some would say a turd.
Why I think fits this convo everyone would say this 360 would be very streetable but quite a few would say a 318 with this exact same curve would be a less desirable street engine and some would say a turd.
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M Body Coupe,
If you are going to compare LSAs, you need identical cams ground by the same company, with only LSA being different, such as this Isky test. The wide LSA cam made 3 hp more at peak rpm....but was down 19hp on the average.
If you are going to compare LSAs, you need identical cams ground by the same company, with only LSA being different, such as this Isky test. The wide LSA cam made 3 hp more at peak rpm....but was down 19hp on the average.
I'd like to see dyno testing on this.
D. Vizard tested 19,000+ cam combinations for Crane Cams & that is his comment in post #65. In Crane catalogs after the cam tests were done, there are faaaaar more cams on tight [ 108 or less ] LSA's than before the testing. Harvey Crane must have been convinced.
In the 2010 Crane catalog, the very first SB Chev cam is 184/194 @ 050....on a 104 LSA, power range 500-4000 rpm. 104 LSA would have been unheard of 25 yrs earlier...
In the 2010 Crane catalog, the very first SB Chev cam is 184/194 @ 050....on a 104 LSA, power range 500-4000 rpm. 104 LSA would have been unheard of 25 yrs earlier...
Jersey Devil
Well-Known Member
With ALL his Expertise, in the recent Wiengartner cam challenge. He wasn't even close to the top of the leader board in any of the performance categories.
be fair, his LSA was almost the same, his exhaust duration was to short, so the exhaust port/header was not so efficient as he expected.
Doesn't change that I'd like to see someone do some dyno tests.
True exhaust chooses did played a big role but when you brag all day long for years your the best of the best and fall that short don't look good. Eight cams that had a 110 to 115 lsa did better than him seven had more than 111 the 5th place had a 115. There was only 2 other cams that ran a 108 like him one did worst and the other came in 3rd and one guy ran a tighter 107.1 and did worst, you can't say 108 was proven optimal.
Yes if I hired him to pick a cam in that instance I wouldn't of been overly happy, but not saying that he's not able to do better on average, guess we'll see how he does with the Ford.
He did retest some of the cams with a bigger header don't know if he did DV's.
If you really understand him and his methods you would immediately think he did something wrong or was not following his own methods. If you used his methods the right cams were in the range of the ones that won the challenge, no question (I ran the math numerous times and had my choice of what cam I would have selected) If you watch his videos his says what I had guessed. If he chose the best cam from his methods there would have been 3 cams almost identical so there was not a lot of learning from that. He chose a cam that filled a gap in the field of contestant's to validate his program he was trying to get out (which I think is now released for SBCs). He was using this as a test for verification of his program. People who are competitive would not understand that, engineers wanting data would.
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Agree, but I do believe his basic premise can be useful sometimes, that people tend to run to wide of an LSA and it might be better to sacrifice some duration for LSA, as for his formula don't think it gives optimal but knowing the results and having that number in the background of your mind while picking a cam probably doesn't overly hurt.
So far of all the LSA test (5 or so) I've seen so far the average seems to be around 3 lbs-ft per degree of LSA, little as 1 to 6 lbs-ft, the trend I've notice on the few there is, going tighter on 116-120+ gonna give higher gains than tighter on 114-110. Not saying this definitive or people should use 3 lbs-ft as a rule of thumb or anything but what I've kind of noticed.
I'm no DV fanboy but not a hater either like a lot of hobbyist I did read a bunch of his stuff and he definitely had influences how I think about some things (with a grain of salt) he is a good first step but some treat his words like gospel.
If you look at the results there was no huge common denominator between spec of the top ten or even top five cams, they where all over the place, is why the test results were somewhat surprising. So his worries was unfounded or a convenient excuse.
Top Ten
Intake 235 to 255
Exhaust 246 to 263
LSA 108 to 115
Overlap 12 to 38
But one trend I did see was cams that did well with a large exhaust duration had a tighter lsa and cams with less exhaust duration had a wider lsa.
He was confounded by a few of the wide LSA's doing so well and asked those people to contact him. I spent a lot of time looking at the data/specs and there was one thing about the wide LSA cams that did well all had in common if I recall was they were rather short on duration (it has been a while and I don't remember things as well as I use to). My thought on that was with the wide LSA and shorter duration I wondered if that increased the cylinder pressures and that it what made up the difference that the small LSA and longer duration cam with lower pressures were. I did not care enough to spend any time trying to calculate all that. At the end of the day I was not convinced that doing nothing but swapping cams was a good test anyway as in my opinion a cam is not a starting point for and engine build. Once you have selected things like, cylinder heads, compression, cylinder pressure, and where in the RPM range you want the peak power then there is a cam that matches that combo of requirements. After thousands of runs on Performance Trends engine software it was clear you can not do parametric changes of one thing at a time and draw any conclusions. You change one thing and you will de-optimize something else. You have to make multiple changes to ensure that different part can work at it optimal point overall.
And that’s the issue with that whole test. Nothing was optimized for any cam. Nothing.
You have a giant pile of data and the only data that matters is the winning cam was closet for that engine with that tune.
DV’s methodology is ok. But that’s it. There is much better math out there.
Is his math better than opening a catalog and picking a cam? Yes.
Is his math better than calling some mass cam grinder (who isnt grinding most of the SFT or HFT grinds anyway) and letting them sell you a catalog cam? Yes.
For someone wanting to get very close there is far better math out there.
DV is like elementary school. We should be working to get better than that.
M_Body_Coupe
Well-Known Member
Sure...if I have a bottomless pit stuffed full of $$$, and the time to allow me to do this...lol, which I do not!
My post was about a real-world experience of mine, with close-enough cams (heck, my biggest problem with even saying that is due to the flat tappet vs hydraulic roller difference).
That's what I found also.
Quite possible.
Wasn't that this test, for these people to come up with the right cam for this combo and apparently there was a few ways to get similar results.
True, I agree with that, but most aren't building a highly developed race engine, so it generally comes down to situations of just picking which LSA without optimization for each to see what way is best.
M_Body_Coupe
Well-Known Member
...again, ideal world situation, etc, etc.
Look, the combo I put together works for me. Is it ideal? Is it the most TORQUE/HP under the curve?...probably not, but it is the right combo for this car as I compare the butt-meter readout of the 108 LSA vs 112 LSA building blocks. End of story.
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Valid point. That said I specified a cam based on DV methods before the actual tests from what I knew about the build and I was within a few degrees of the top cams with LSAs of 108 (also chosen by DVs methods).
That is why I say DV did select a cam he knew was not optimal just for another data point. The cam he used in the test was WAY out of what his methods said it should be. The duration he used was on the boundary of an RV and street cam based on his tables. The durations that made the most power were the durations he suggests you use for a street/strip cam (what I used in my phantom design).
I agree unless your building a engine vary similar there's not much you can use towards other builds. But I do think the results were interesting since the cams that did well the spec were all over the place there was some trends if you look hard enough but still was fairly random even in the top 5.
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