Doug G

110 LSA w/ 4* adv. ground in is 106 ICL....Seen more than one come in at 109.5 LSA and that would make the ICL 105.5 most of the time.
My last 3 were that way.

VLS1

Well aware of how dialling in a cam works, but that alone doesn't determine the valve events.

speedtigger

iTrader: (16)

I bet a lot of you would find this conversation about single plane cams interesting:
http://www.yellowbullet.com/forum/sh...d.php?t=839634

VLS1

I think you may be trying to simplify matters with the proposal of these two off the shelf cam ideas. If the Victor Jr intake typically peaks at around 6400-6800, then ideally you want to work out the valve events to maximise torque from say 5000 onwards in a street engine with drag racing being the focus.

The thing with that is that every cam grinder will have their own idea on what cam specifications will achieve this best. I think this goes back to my post of the fact not a lot of guys seem to have gone super quick with these carb combinations, so therefore maybe not a lot of real world R&D has been done to work out ideal cam grinds for these applications.

I used to spec cams many years ago for more traditional flat tappet/hydraulic applications, and the same basic rules apply with any cam which comes down to the end users expectations of how the engine will behave. But look at how many off the shelf grinds are available for drag race SBC/BBC, SBF/BBF etc, and yet still a lot of guys will go custom grind because they, or their engine builder, will have their own ideas on how the cam should be spec'd to their liking.

BigEd_72455

iTrader: (7)

I would think this response says it all...

The fact is every person has their own idea of what their truck/car/suv/whatever should do to make them happy. And the cam maker/grinder is going to get a different answer from every single person they talk to. For example, despite my having a single plane intake and the ability to go way higher than 6000 RPM, I don't have the supporting parts to do it (cam & springs), so my shift light is set at 5800. And I actually feel I would do better shifting a bit earlier.

Since my track time with this setup has been limited to 5 runs (4 under full throttle) I am by no means an expert as to what it will do. I still have a LOT of stuff to finish up and work out to make this work to its potential, whether NA or bottle fed. Working to tune the carb more, adjusting suspension, tire pressures, a bunch of tiny little things that can affect the way the truck runs.

Simple fact is, no 2 cams will give exactly the same results. And even with 2 perfect twins, SOMETHING will make a difference...

speedtigger

iTrader: (16)

I don't think so. There are tons of guys doing the cam-and-go-racing LS swaps these days. And, I believe that just a couple camshaft cam really suit most of them. Why? Limitations. All these guys have roughly the same limitations.

It is the intake valve to piston clearance that really limits what kind of cam you can do without fly-cutting. With the single planes need for an earlier intake valve close, it becomes the intake valve open piston-to-valve clearance that really limits the intake duration.

Consider that most of these budget SBE, SLB & junkyard builds have limited compression (9.5:1-10.8:1) and a limited appetite for RPM of about 7000 RPM and you have really narrowed down your possibilities. Then consider that the the single plane intakes that the vast majority of these cam-and-go combo all have roughly the same characteristics. So, we continue to narrowed it down.

If you read the thread and understand the piston to valve and ideal intake valve close limitations, you see how the possibilities really get narrowed down. So much so that you end up with a set of specs that are almost dictated to you.

That might be true for some, but look at the success that cams like the T-Rex, Polluter, Magic Stick, Vindicator, El Diablo, etc, etc, etc. These were commercial successes because they exploited the fact that a lot of guys were running very similar combinations and they could make a camshaft that would fit the majority of their needs. In addition, once a few of these combos proved themselves, guys started buying them because they were proven.

I am actually kind of amused by the guy with the LS1 Camaro with: LS6 intake, 1 3/4 headers, stock heads and a 3600 converter who thinks he is going to unlock some previously undiscovered, amazing amount of hidden power with a custom camshaft. Everybody and their brother has that combo. What kind of cam that car will need is not exactly a mystery and what they need can be bought off the shelf from many suppliers.

Now in speaking to what a guys "tastes" are in regards to idle and "personality" surely does vary in the late model Camaro/Corvette market. However, I feel pretty confident that pretty much all of the cam-it-and-go racing crowd would all be just as pleased as punch with a thumpin' idle and a 6500-7000 RPM peak power.

BigEd_72455

iTrader: (7)

I would be too, IF my valvetrain supported those levels of rotation.

Which currently they don't.

But all in time....

VLS1

Okay, if we are talking bolt in application with no piston reliefs, this is going to limit options especially with the bigger L92 heads. If fly-cutting pistons is no issue, I'd suggest a cam around 232-234/240-244 @ 109/110 LSA on a 105-106 ICL as close ballpark for most street/strip setups.

speedtigger

iTrader: (16)

The thread I created on the bullet created a space for Brian and Martin to spell it out. Martin indicates that he does not go above an intake duration of about 231 with a single plane engine unless he is looking at a RPM range that extends above 7000 RPM.

The only intriguing thing to me would be experimenting with earlier exhaust valve opens like Brian Tooley has on his latest LS3 dyno sessions. If the same thing works for factory cathedral port heads, we could end up with some really large splits.

dudek

ive got the same cam in my current combo.

08 ly6 with the asa cam and yellow valve springs
gm intake
holley 750
th350

never tore the motor apart just slapped everything in and ran it.
u ran 119mph in a foxbody, the only outting to the track.

made a few minor changes this year, cant wait to see what it does with some time at the track.

VLS1

The intake valve closing event is probably more a crucial factor than the duration itself, again being in the low 230's may be more suited to having the intake valve opening event clear piston safely while maintaing the preferred intake closing point. I think Martin sort of explained that in that closing intake earlier is preferred with the single plane application. Opening the valve earlier and therefore extending duration beyond mid 230's could also be beneficial depending on cylinder heads to help maximise cylinder filling by getting the intake event happening sooner. This may be more beneficial with large intake ports which have less off the seat velocity etc, although this may then want an earlier EVC point to avoid excessive reversion.

Point of the matter is that all camshafts have some sort of compromise, especially for the situation of running these large valve L92 heads with stock pistons which is probably the most popular thing amongst the drag racing enthusiasts. Think I can recall reading that fast89stang runs a 231/243 @ 111+3 and has run in the 6.30's and yet Dmmizell old L92 6.0 was apparently running 239/247 @ 110+4 and went 6.27 on his 9.87 pass. Running these in a cam calculator shows some notable valve event differences, mostly with IVO point.

So what works best? Really depends on the whole setup of the car and can't really be decided without doing a cam swap on one car only and preferably at the track on the same day with no other conditions changed.

speedtigger

iTrader: (16)

Dave's car has pistons with valve reliefs. Fast89mustangs cam probably does not require valve reliefs.

If you look at the EPS single plane cam, it has a really early intake valve open and a wide split: 236/248 108+2. The one report I heard about that cam is that it really likes to spin and really responds to a very high stall (5000+).

UOP

Interesting conversation so far.

I took your recommendation and asked Martin to spec a cam for my build. I'm not sure if he would appreciate me giving the exact specs online but they are similar to his LS3 Street Heat stage 2 cam (229/244, .61x,.59x, 112+4), but on a tighter 109 LSA. Nofly-cut, and should make max power somewhere around 6500. Do you guys have any opinions on this cam for a car that spends most of the time on the street (I drive it everywhere)? When I first read the recommendation I was a little surprised, thinking it was way more cam than I requested, but after comparing it to his off the shelf offerings it seems middle of the road.

As far as other progress, the new motor should be delivered next week and I've got a long list of parts ready to order. Pretty excited I was able to score the L76 for not much more than a LY6. I've got to deal with the added cost of removing both VVT and AFM but it'll be nice to have the weight savings the aluminum block offers.

Thanks again.

fast89stang

iTrader: (2)

My pistons were notched. I have. 095 clearance. I was told to check, and did. I ask Martin, and he said without more compression, the cam was about as good as it could be.

speedtigger

iTrader: (16)

I think it will be a monster in your light little car. It will have a very rowdy idle and pull like a freight train.

UOP

Are you running a similar car in your car?

VLS1

All these cams are going to behave with similarities, a few degrees here or there in duration isn't going to make a huge world of difference. Will the larger cams see a tenth or so quicker over the 1/4 mile? Maybe.

That EPS cam doesn't list an ICL that I could find either, so not sure about that. Howards have had a similar cam for years, but I don't agree with these large split cams for 10:1 motors which most guys seem to end up with, like the above mentioned examples for instance. I've experienced first hand what over-cammed motors can lose, but if running stock exhaust ports this may be somewhat advantageous to an extent.

VLS1

Never assume you won't have to fly-cut, if you've smashed a valve like I have in the past, you'll understand why. If notching pistons is a concern I'd go with something smaller.

fast89stang

iTrader: (2)

Cam is around 230-243. Lift is 600-622, but not exact numbers. Cam card is at work

VLS1

Just as I would have suspected, and the OP will also most likely require reliefs cut in pistons.

Martin knows his stuff, going much bigger in cam with a 10:1 motor will only lower dynamic compression and can possibly go backwards in power.