Not when I ordered one last year.
Good Cam Choice?
- Thread starter siuauto
- Start date
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In the past, present and current systems I can not answer on, the tighter LSA and the computer do not mix very well as the tighter overlap seems to not work very well with the computer. Perhaps confusing it? IDK.
I’d say if you can tune it (or somebody else) the narrower LSA is the way to go for more low end torque and power everywhere. It would be worth it IMO, if it can be done.
Past experiences may have jaded the idea. (?)
What system did Rich use. I did see the video. I don’t remember the system. IIRC, it’s a Holley, but what exact model it is I do not know.
I do remember in the past people having a hard time with the low LSA & there FI. I have not kept up.
Rumble,
I think it might have been the factory EFI, not 100% sure.
It was a veeeery interesting LSA test.
Here is another one, using a carb. 350 Chev using big cam, 262/266 @ 050. Identical Isky cams except for LSA: 106, 108 110.
110 made 3 peak hp more..................but lost 24 ft lbs average through to 7000 rpm to the 106. 108 was down 13 ft/lbs compared to the 106.
I think it might have been the factory EFI, not 100% sure.
It was a veeeery interesting LSA test.
Here is another one, using a carb. 350 Chev using big cam, 262/266 @ 050. Identical Isky cams except for LSA: 106, 108 110.
110 made 3 peak hp more..................but lost 24 ft lbs average through to 7000 rpm to the 106. 108 was down 13 ft/lbs compared to the 106.
I'm plum impressed there's someone with the BALLS enough to run a solid roller and not hide from one under the kitchen table cryin for his mama. Good for you. I bet it'll haul the mail.
TT5.9mag
Two atmospheres are better than one
@rumblefish360 and @Bewy Richard Holdener uses the Holley hp ecu on just about everything, and he is only concerned with WOT which the tight LSA would not be an issue tuning for. It’s the idle and drivability tuning that is much more difficult the tighter the LSA gets.
Excellent. Thanks for that and helping me with choices down the road.
siuauto
Well-Known Member
I appreciate all your input, and although a tighter LSA would give me better all-around power and better low end, maybe this cam with a 110 LSA might be better for the street since I am using EFI and have a 4-speed.
siuauto
Well-Known Member
Maybe I am just stupid. I do have some concerns over the valvetrain geometry since it's already a struggle with a flat tappet, but I am confident that I can get it pretty good. I plan on pulling the intake and checking rollers periodically and staying on top of them. Lord knows I have broken plenty of parts in the past and didn't cry over them, so what 16 more? To me, it sure beats the issues with flattening cam lobes.
Call Mike at B3 Racing Engines. He's a member here and can get you all set up. @B3RE There, I tagged him for you so maybe he'll chime in. He helped me get the geometry on my modified slant 6 head right after I put 318 valves in it that have .300" longer stems than the slant 6.
...and you ain't stupid.
siuauto
Well-Known Member
Yes, he has helped me in the past and I do plan on contacting him.
I think you've got that kinda wrong. On every single dyno simulation I've ever run, the tighter LSA gives up low RPM torque and power for a higher RPM peak torque and power. Every single time. The wider LSA also broadens and flattens the torque curve. Every single time. I think guys get hung up on peak this and peak that and forget about everything else sometimes. For the street, I'd choose a 110 or possibly even wider LSA. .....now here come the Vizard rule guys to tell me how wrong I am. Chrysler factory engineers used 113, 114 and 115 lobe seperations, so they can call them stupid, too. lol
Good. He's a super guy. Genius even.
dirty white boy
50 yr old Juvenal delinquent
cams with lotta over lap that cripple vacuum is known to give efi issues with idling and low rpm driving. computer needs a good vacuum signal to read to know what to give engine....in theory, i have no experience but have studied efi a lot as id like to try a sniper or 2 out my self one year...
siuauto
Well-Known Member
I have done 5 now and they all are great. One of them is a tunnel ram 440 with duel Holley sniper and it’s a dream to cruise around.
TT5.9mag
Two atmospheres are better than one
There is a reason 90% of shelf cams are ground on a 110 LSA. It’s a good compromise for an all around, “do everything” camshaft. Sure if you were picking the fly poo out of the pepper and wanted to have “the perfect” (news flash, there is no perfect cam for every situation) cam ground, I’m sure a grinder could probably come up with a different spec but honestly the 10lb/ft down low or the 10hp up high you aren’t going to notice in a street/strip car. Use what you have. If you want the engine to do something different change the cam later on.
I with that! ^^^^^^
When you go tighter lsa you could go with less duration keeping a similar overlap. Keeping a similar idle etc.. But you got decent size heads for the cid for the rpm you'll probably be in, I doubt your given up a lot going with a 110. Everything thing is a series of compromise, max power from a head is like 2.5 hp per cfm so most people are leaving a lot of power on the table. Where you draw the line on choices is kind of arbitrary to the individual.
Between the (Red) 108 & (Green) 112?
I agree. It’s drivers choice. I’ve installed 112 LSA cams on purpose before for the smooth idle and easy take off. IMO, it’s not a bad thing. Works great on a driver you want to drive as if it was stock.
Even more so when max power isn’t really the goal, or care.
That 120 LSA takes a beating!!!
I agree. It’s drivers choice. I’ve installed 112 LSA cams on purpose before for the smooth idle and easy take off. IMO, it’s not a bad thing. Works great on a driver you want to drive as if it was stock.
Even more so when max power isn’t really the goal, or care.
That 120 LSA takes a beating!!!
This engine wasn't that sensitive between 108 vs 112 doesn't mean it holds for all combos but bet most would react similar, be interesting if he went even tighter with 100 & 104 see is the gain stops or breaks even or even starts losing bottom end.
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TT5.9mag
Two atmospheres are better than one
Yup the 110 will fall directly in between them. I’ve tuned a few LS cars where guys have installed “choppy” low lsa wide duration split cams and imo they do it mostly for sound. After a while of driving the car they seem to want a different cam because the sound isn’t worth the drivability headache. Especially with a stick shift.
You got basically 3 different performances you got to worry about on a street car. Everyday normal driving /6 type performance, part throttle passing mild fun performance and full throttle max fun performance and how the car reacts going between each. The more you try to maximize all the less efficient it becomes with each or a lot of money/r&d/engineering got to go into your car to find a balance.
TT5.9mag
Two atmospheres are better than one
Usually on a more serious effort you’ll see that huge lsa carry a bit more (longer) up top than it did in that test. I think that was more a function of a relatively mild combo running out of cylinder head as they all roll over about the same spot. Maybe some valvetrain instability happening there as well.
Newbomb Turk
Well-Known Member
That’s what I used to think but Godbold says in his book that they use the wide LSA for piston top geometry. He says even a Pro Stocker (pre EFI and rev limit) can use a tighter LSA but the valve pockets get too deep and the BSFC goes up. So they widen the LSA to get the valve notches less deep
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