0Presence Dist.

I use patG for all my custom cam specs and can set you all up with a nice cam package and any other goodies you may need

CI GS

What are the "fallacies and misunderstandings" in my post?
And which professional recommendation do you think I should I go by?
Because all I see on here on the cam install threads is dissent and disagreement between the various professionals on here, even on the basic fundamental aspects of cam specifications.
And after all, this is a Comp Cams shelf grind that I'm asking about. But I suppose they wouldn't know what they're doing, would they?
I've been at this for around 30 years. It's not what I do for a living, but I've spec'd and installed more cams than I care to remember, and they all ran fine. That doesn't make me a professional, but after all, my post was in the form of a query, was it not?

dev1360

I wasn't trying to come off as abrasive. My apologies. A lot of people look at LSA and think of it in terms of idle quality and torque. While it is used in the overall scheme, and can shape the power curve, it's not a tell-all. Lobe design is also extremely important in reliability and power under the curve. Overlap, and valve events along every point of lift are extremely important.

I honestly know just the slightest tip of the iceberg on cam design, but I know enough to know that I need a professional lol.

PatG has done two cams for me now, and both far exceeded expextatjons, especially in a daily driver. Pat also explained to me about cam lift vs port flow when he spec'd a lift of .629 for the intake and exhaust for my stock LS3 heads. Martin at Tick also agreed with higher lift for LS3 cams.

Finally, with the recent core degredation, and "cam whine" issues, I would shy away from Comp. But like anything on the internet, I'm sure you'd be fine. PatG uses EPS, who sources their cores and lobes from Cam Motion, who incidentally called out Comp on their quality issues and offered to fix Comp cams for free for anyone who asked.

My results are posted in this thread. And for a stock intake, stock TB LS3, I think they speak for themselves.

push

I would definitely recommend talking to Brian Tooley. Just tell him what your goals are and he'll get you squared away. Custom cams sound great, and they have their place, but there is nothing wrong with an "off the shelf" grind. If they weren't solid performers they wouldn't be so popular.

CI GS

Okay, fair enough. And to the extent that I may have come across likewise, my apologies as well.
I have heard nothing but good things about Pat G.
I had no idea about Comp having quality issues, but nothing surprises me anymore.
I have studied everything I could get my hands on over the years on cam theory and design, so I get what you're saying. I'm also looking at the Tick cams as well as the ones by BTR. I definitely want to shy away from cams with big lift and duration because I don't want to have to fly-cut my pistons.
And I really don't want an all out effort cam anyhow - I want something that is easy to tune and something with little overlap, in the event that I go the F/I route.
BTW: I thought this comp cam would be a good compromise of power and "streetability" for the OP to consider, which us really why I posted it up.
To be honest, when I buy a cam, I'm going to do the entire package from the same place: cam, springs, pushrods, 3-bolt timing chain gear, C5R chain, upgraded trunnions, etc. and will most likely only source it from someone who can offer me a baseline starter tune too.
The main reason I can't make up my mind on a cam right now is because I can't make up my mind on whether I'm going to do an ECS kit or not and how big a converter do I need or want to live with etc.

CI GS

I am looking at BTR because he has a good reputation and offers a complete cam package. I just need to figure out exactly what I really want to do with the car first.
And I'm not going to get wound up into this custom cam thing either, because, at the end of the day, who's to say that I won't end up changing other parts on the car (as I tend to do) and then, all of a sudden, my custom made cam might end up being a custom misfit cam

dev1360

Brian Tooley has forgotten more about cams and head design than most will ever know. I have his .660 springs and trunion kit in my car. Very good stuff, and a great guy to work with.

push

Yeah, I was going back and forth and about the only thing I knew I wanted for sure was decent power without having to swap springs every 10k miles or flycutting. After talking about it with Brian for a little I went with his stage IV ls3 cam. I was really impressed for as busy as he is he responded to my e-mails so fast. I've had the cam in for a week so far and it's been great. Went on a ~800 mile road trip right after the install and it's a great streetable cam.

CI GS

I'm thinking about his Stage II cam, with 225/238 duration. That is probably as big as I want to go, to be honest. I have seen articles and threads with hundreds of dyno tests on LS3 cams, and I've noticed that with the stock heads, there is a point of diminishing returns where more lift and duration result in increasingly smaller gains at the expense of poor idle quality and low end power. I would rather leave 10-15 hp on the table than give up idle or driving quality, mileage and easier tuning.
Besides, I already have a race car with a 298/306 duration, .824" lift, 109lsa cam, so when I want to get my jollies, I can always crank that up and listen to that breathe through its 4 1/2" open headers!

SpinMonster

I don't sell cams and merely shared what I have found that works.

My 'SpinMonster cam' is 4 degrees overlap and has hit 500rwhp on so many cars that I fail to see why some still consider more overlap. All these votes for cams with big splits and huge overlap make no sense if they're putting down the same or less power. A cam making 490rwhp at 14.5 degrees overlap is crazy. You have all that overlap and it isnt a record power result. I tried a 230/242 and a 230/234 and they made the same power but the smaller cam made more TQ under the curve. Why use such a big split?

I don't post the continued results on my end because it looks like I have something to gain so I let other's dyno results at independent dyno tuners do the talking.

I shared thinking it would help the industry. The cam is a 230 XFI/234XER 114+2 for an LS3. Its 4 degrees overlap and drives great. Its been installed by my shop for 6 years and I have not had a single failure in any car it was installed on. Cam only it made a high of 501/465rw on a dynojet 248. It isn't a spring killer. It isnt breaking valves. It's easy to tune. My cam hits 400rwtq by 3500rpm and holds 400rwtq to 6500. It pulls to redline needing no additional ex duration to extend the HP peak higher. Cam only (stock head) cars have hit 129+mph trap speeds with it. Get a cam that has factual results from a bunch of cars. Varying headers and air cleaners do not require custom cam specs. My cam was installed with every varying bolt-on and it made zero difference.

Common stock untouched head results. Note the low and mid TQ as well as it pulling to redline:


Please understand that I like helping people and I charge nothing for my 'specs'. Advice is always free and I have made many friends from this hobby. Feel free to send me a PM if you have questions. I answer all of them.

If anyone wants to buy this cam or the Trick Flow package, Bob at PEAK SPEED sells it all and he is a forum vendor. The cam is $385. I make nothing from the sales.

http://peakspeedshop.com/

This is with trick flow 235 heads and he left the compression at 10.7:1 for forced induction. He made 521rwhp/469rwtq and he had only average numbers with just the cam at 487rwhp. At 11.7:1 on 93 Octane, I see an additional 15rwhp and 18rwtq with that combo at 11.7:1 compression....yes 535rwhp on a 6.2L.


You can bump power another 20rw if you add N/A meth injection. The gains are documented in this thread:
http://forums.corvetteforum.com/c6-t...lications.html

Even my LS7 SpinMonster cam is 6 degrees on the split with Trick Flow heads and that hits 622/578rwtq to the wheels. Selling the LS7 heads for 2200 and buying the Trick Flows at 2600 is way better than a ported LS7 head. Brian Tooley knew this when he built his max effort 700hp N/A motor:
http://www.superchevy.com/technical/...stroker_build/

CI GS

I think I have now read through every thread about cams on here, and just about every one invariably has at least one person who has your cam and has nothing but good things to say about it, and it obviously by all accounts makes very good power and torque, although it doesn't follow the "beaten path" approach to LS3 cam design.
I understand the thinking that since the LS3 head has a relatively weak exhaust port, and it therefore needs all the help it can get on the exhaust side, but bigger is not always better, and there clearly must be a point of diminishing returns where overlap starts to kill torque production.
In any event, empirical data is incontrovertible, so no one can say that the Spinmonster cam doesn't work, even if the popular "theory" dictates otherwise.
I am no cam expert, but these massive 10*+ splits on the bigger cams make no sense to me either. I understand doing it on the factory cams and one of the Lingenfelter cams I've seen ( GT11), where the intake duration is so short that there is no overlap. In fact, I've read somewhere that the Lingenfelter cam was designed with short intake duration and a wide LSA to avoid overlap, simply to make that cam have stock-like idle characteristics. That seems to have been the initial thinking behind the large split cam design.
Some folks want a rough, choppy idle, but that comes from overlap (or a bad tune) which usually means your low end and midrange torque will be adversely affected.
And we should also bear in mind that we're talking about hydraulic lifter street cams here. In my opinion, most of the larger cams grinds I've seen guys touting on here should only be used with solid lifters, because there's also a point where the limiting factor is literally the hydraulic lifter. If we were talking about a forged internals, solid roller setup where you're going to turn it 9000RPM, that would be a different story. Then we can get as wild as we wanted with cam specs. But, then again, the folks that run those kind of builds will most likely be running a good flowing aftermarket head anyway, that doesn't need a big split to get the exhaust gas out of the cylinder. This is basically what I understand you to be saying about using the TFS rectangular port head.
And I am also cognizant of the old adage, "there's more than one way to skin a cat". This applies to engine combinations too. Even with two strokes, I have seen different folks using different methods to achieve basically the same power output, albeit usually with different torque curves.
At the end of the day, I feel obliged to say that I am impressed by your knowledge and I think that we are fortunate that folks like you take the time to explain your thinking and methodology, for free. To me that makes spending time on these forums worthwhile.

RossNZ

Sorry, I meant 1"7/8 headers and thottle is only 90mm. A big thanks to everybody who took time to reply and with a bit of expert help I have decided on a SpinMonster 230/234 .612/598 114.

SpinMonster

Thanks for your reply.

Weak exhaust ports on the LS3 head

The LS3 head doesn't have a weak exhaust port. Its a high velocity port. Somewhere after Tony Mamo demonstrated that CFM does NOT equal HP, the LS3 head came out with a 330cfm intake and 193cfm exhaust and everyone forgot the velocity message. The AFR 205 flowed 305cfm and made 500rwhp with a 236 intake duration cam on an LS6. Big hogged out 243 heads at 340cfm made no power. By the way Tony used a single pattern 236 cam for that. Its likely right around 232/232 114+2 that a cam is going to make the same power as a 230/234 or a 228/236 but selling anyone on a single pattern cam is like selling speedos in Alaska. I tried a 230/230 and it made 485rwhp 440rwtq in the LS3.

If you run way too much overlap, you get reversion. Overlap is why gargantuan cams dont get much past 500rwhp with that head. Porting it makes little power as you only lower velocity more. Still porters sell CFM.

The other issues with the LS3 heads is that you can't increase volumetric efficiency by bumping compression much due to limited p-v clearance.

The Trick Flow 225 makes 530rwhp on the LS2 (G6X3 cam) and has done 10.4 in the 1/4 at 134mph on the challenge list. The trick flow 225/235 is optimum for the LS3 and flows 330+cfm just like the LS3 head but its way smaller an intake runner for much higher velocity. Porting the LS3 head hasn't made any real power. Why spend silly money porting the LS3 head when you can sell them for 1000-1100 with the intake to get the 2600 dollar Trick Flows. Save the 1500 bucks from porting to put it toward the Trick Flows and bump compression to see 535-540rwhp. These higher compression LS3's with trick flows are way better gas mileage too.

Cathedral Vs Rectangle

The cathedral port is better for a street engine because the low rpm power is made on the short side radius (less volume in that part of the runner) and the high rpm is made from the higher volume top of the runner giving you the best of both worlds. Rectangle ports are too big for the same throttle response in low rpm. Brian Tooley himself chose the cathedral ports for his max effort 700hp motor passing on the LS7 heads.

Cartek exploits this top to bottom variance but Julio's proprietary porting is not for discussion here. His porting on GM castings has among the best results I've seen including LS3 heads.

Factory cam big splits

The factory cams use big splits for an entirely different reason than the masses here. When you take a 204 intake duration on a 117 lsa and put it in a 6.2L, the power falls on its face peaking too soon. The big split is used to extend the power out past the HP peak. Bigger cams such as a 230 intake duration on a 114 peak right at 6300 where the composite intake manifold forces the peak due to its runner length. This invalidates the use of big splits to carry the peak power out further. The same thing applies to the LS7. A 211 on a 118 would die at 6000rpm if it were not for the 230 exhaust duration. My cam carries its TQ out to 6500rpm at 400rwtq. It doesnt need exhaust duration to extend the peak. To illustrate, as you increase intake duration the size of the split needed to reach top end power near redline decreases.

One reason the aftermarket LS7 cams all have huge exhaust duration is that people wont bump compression. Cam designers know that to get more TQ down low they need a sooner intake valve close so they use small intake duration with a tight LSA mandating you use more EX duration. This is negated by bumping compression but most cams are bought by people who wont do this. The Trick Flow 235 on the LS7 makes 610rwhp and 570 rwtq with a 6 degree split cam that I haven't released yet. It will be available through http://peakspeedshop.com/ , a forum vendor. A 236 on a 114+0 doesnt fall on its face at 6000. Too many just say that GM uses a 19 degree split for its LS7 cam so all LS7s need big splits...wrong. Advancing the cam shortens its power band but raises low end TQ. This is irrelevant if you raise static compression to your DCR limit on the fuel you run.

You want a choppy idle?

This is my cam wth stock LS3 heads.......its plenty choppy if you want it that way. If you want more chop, decrease idle rpm & timing, make it leaner at stoic. If you want less, raise the idle, add timing, run it richer. Keep in mind most of the country runs 10% ethanol in the gasoline so its 14.1:1 stoic not 14.7:1. GM cars come from the factory set for 14.7 so its too lean at idle for the 10% ethanol you are likely running. The second one has less chop because its idle is higher during a cold start up but it serves to show how lope can be tuned out. As the idle drops in RPM and runs less timing, the chop comes back. Raising compression improves drive-ability and smooths idle. The cam acts like its in a bigger displacement.





My cam was designed as a compromise for the guy wanting to pass the sniffer (my 230/234 passed in NY), wants to have near perfect drive-abilty, and wants a better option for higher compression later on leading to 28-29mpg fuel economy. If you are 100% sure you're never pulling heads, PatrickG's excellent 230/238 cam is a great choice if tuning the additional overlap isnt an issue. The benefits of the tighter LSA and more exhaust duration are negated if you bump compression which boosts power 4%. You cant run as much compression with that cam as you can with mine on 93.

If you have a special case, I recommend PatG for a custom cam design. He is great to deal with and knows the tech side better than me. I just share what works for me.

Hope this helps.

CI GS

Thanks very much for sharing this all of this. It is more than helpful. It's a rare occasion that someone takes the time to explain their thinking and share their hard earned experience, especially on a topic that is as complex (and controversial at times) as cam design. I've always read that cam and heads need to be designed together to get a desired result, which makes sense.
I pay a lot of attention to this kind of stuff, because I live overseas and the cost (and inherent delay) of shipping and import taxes and the fact that I can't drive my car to a shop to get it tuned, dictate that I have to find parts that work the first time. Consequently, whenever I buy a cam, I need to make sure it's one where I can get at least a decent base tune to work with, because I've had that experience before when I bought a VVT cam from Mast and then they told me they couldn't help me tune it (and if anyone thinks LS3 camshaft design is black art or controversial, try googling "tuning an L92 VVT cam"!)
The last thing I want or need is something that sounds like an elephant with diahorrea and runs like it too.
I will buy a cam that I'm convinced makes decent power, doesn't destroy valve springs and is easy to tune, over one that is labelled "most powerful cam ever", any day of the week. Because it just doesn't make sense to sacrifice reliability and idle quality just to end up spending a bunch of time and money trying to get it tuned to replicate or eclipse somebody else's big dyno number.

SpinMonster

These three cam designs have all made a verified 501rwhp on a stock head LS3:

235/245 111 LSA--18 degrees overlap 10 degree split--.646 lift LSK intake lobe
227/239 114 LSA--5 degrees overlap 12 degree split--.614 LSL intake lobe
230/234 114 LSA--4 degrees overlap 4 degree split--.612 lift XFI intake lobe

They can have a tight LSA or wide, a big split or tight, and big overlap or little. What this says is that cam specs don't have to be designed to a specific head and a variety of cams work. It also shows a head is really what limits the result, not the cam. If you went with Trick Flow 225s or 235s, the first cam would far outperform the other two simply because it allows the bigger shot of gas along with a high velocity airflow to support it. I think the reason the biggest one doesnt work any better is due to reversion.

The only other factor then would be drive-ability. Since overlap is inversely proportional to good drive-ability, in a setting of the same power, you should go with the least amount of overlap. All sound mean. You also get better emissions. Lope is unspent fuel burning in the exhaust during the overlap period at low rpm. Volumetric efficiency can be restored to bigger overlap cams if you raise static compression to its max which at sea level on most LS heads with 93 octane is around 8.7 DCR (11.7-11.8 static compression with my cam).

You run meth injection even on an N/A car for insurance. When I was a teen, I had a short summer working at a gas station and a vendor came to fill the station tanks and dumped 87 octane fuel into the 93 tank. If you run on the edge of compression, "you are one bad tank of gas away from a new engine"--Doug from ECS. Meth can save you from that. I'm sure it happens. Meth can also make any of the 480-490rwhp LS3 guys hit 500rwhp with out requiring a re-tune.

LD85

So,,, what CFM does the stock LS2 or LS3 head flow? Where does the CFM tail off, I cant imagine that the LS2 or LS3 heads CFM flow peaks beyond .610, am i wrong?

SpinMonster

The 243 LS2 head is 260-280cfm from a 210cc runner depending on the motor (LS6 vs LS2).

The LS3 head is a 260cc runner that flows 313 cfm on a 6" bore. I've seen it make as high as 355cfm but this enlarged the intake runner to 272ccs. Lingenfelter had flow data on their website for these heads making 332cfm but it was on a 4.125" bore.

The Trick Flow 225 for example flows 338CFM but does it from a 225 CC intake runner.

Flow numbers at .700 wouldnt benefit anyone running a daily driver cam.

Orr89rocz

I wouldnt say that...depends on who ports them and what you are trying to acheive. Seen ported ls7's make 680 wheel hp all motor on 92 octane. Wasnt cheap but didnt necessarily define what makes tfs better. Bang for buck maybe?

SpinMonster

680/540 RWHP/RWTQ, still on the factory LS7 short block, 92 octane pump gas, same 257/273 112 LSA solid roller cam

I think solid roller and a 257 cam at 41 degrees overlap puts it out of the running for most people. Solid roller set-ups are not daily driver reliablity. For a H/C combo like that to make only 540rwtq is not so amazing. In fact that combo made only 400rwtq at 3500rpm which is what a 230 intake duration cam makes in a stock LS3. Thats ok for a race engine but not light to light. Street cars favor big TQ. A 4.1" stroked LS3 to 427 with Trick Flow 235's and a more live-able hyd roller cam made 603/583. The smaller 4.065" bore in that 427 isnt helping to hit the numbers you would get on the LS7 but it illustrates the TQ you would have for a street car. This is still only the smaller TF 235. They make a number of bigger heads for max effort results. All are around $2600 for the pair. Brian Tooley knows plenty about porting and went Trick Flow.

http://www.ls1gto.com/forums/archive.../t-341844.html

The best H/C for ported LS7 heads I've seen was 630/555 from Livernois which is a great result but is easily matched by the Trick Flow 235, 245, and 255 heads.

Orr89rocz

When you make big hp at high rpms the torque is goin to be lower. Math equation works that way. And i will disagree about street cars and trq. Big heavy cars may like some trq but light cars too much trq can make a setup very hard to drive. And once geared to match powerband, it doesnt really matter where that trq occurs in the powerband. Gears will put it there. You have to then look at total average power across the rpm scale. The car that makes the most average power thru the pull would win. Stroked or cammed ls3 may make 580 trq but i bet that 540 trq 680 whp ls7 stomps all over it in all aspects of acceleration once geared properly. Hp advantage ultimately shows. Never seen a race motor run slow anywhere, street/stoplight/track/highway. Same way a evo 4g63t can make 922 awhp but only 500's trq yet trap 160+ mph in a 1/4 mile.
But yes higher winding motors with bigger cams do tend to have rougher idles and turn more rpm on highway due to more rear gear required. Street motors do like to be big inch and lower rpm to keep the package more "civilized".
Solid roller may not be ideal for street use but they have come along way in technology and many have run them with great success in street aps. They just require more attention. A 257 solid is more like a mid 240's hyd once lash is taken into account. So its not quite as big as it may first appear. Guys run 240's cams in ls1's in the 9-10 sec range

Tfs are good heads no doubt. Better bang for buck most likely over a set of greg good ported ls7's but cant deny the castings potential there