Justin 87 GTA

iTrader: (3)

I'm ordering the comp cams XE268h flat tappet cam today or tomorrow,.. should work well and be blower, emissions and computer freindly while making good power. check my sig for mods,..i'll have around 8.4:1 compression. so is it a good one to order? thanks

Apeiron

Isn't the overlap going to bleed off a lot of the boost?

B4Ctom1

maybe it will improve exhaust scavenging and protect the head gaskets

unknown_host

iTrader: (1)

For some reason I think that is the camshaft that KingTalon or whatever his name is was running with his blower setup.

83 Crossfire TA

iTrader: (2)

I like it...

Damon

You might like to know that Comp sells a version of the 268XE ground on a wider 114* LSA for less overlap than the standard one (which is ground on a tighter 110* LSA). It's not a custom grind. It's in their selection of TPI cams. I use it in my roots-blown 383.

For a mild blower application minimizing overlap is important- it traps more A/F in the cylinder where it can make power instead of blowing it out the exhaust.

For an agrressive engine with a big blower it's less important- let it have some overlap for good scavenging and cylinder filling at high RPMs and just pulley up to get the boost you need/want.

flrtin1

Take a look at the NX262H its a smaller lift for a blower cam(462/480) but still has 113 degrees of lobe sep.

Justin 87 GTA

iTrader: (3)

what do you like better about the nx262h? or nx262h

They also have the 268ah-14. Is that good?

and the xe268h is a 114, as far as the site says,..damon, what one are you talking about? i heard someone else say that the xe268h is a 110 also,.. but it is showing that it is a 114.

anyway,.. i think the xe268h is the one i'm going for. I hope to have the car run well witht he computer,. brakes work, pulls hard and works well w/ my low compression supercharger. maybe even pas emisions..w/ my egr in place. anyway, any better ideas? there is a crane cam w/ 114 lsa, 467/490 lift, but i forget the duration that is supposed to be good also,.. how does it compare? thanks a lot!

CrashedMatrix

i put the nx274 comp cam in my blower setup it works awesome!

F-BIRD'88

A Crane H278-2 is a better blower grind than the Xe268.

Specs are 222-234 @.050" .467"-.494" 114 LSA.

www.cranecams.com

Justin 87 GTA

iTrader: (3)

so, what makes this crane h278-2 grind better?, and does it have too much duration for the stock fmu, drivability, brakes, possible emissions and so forth? thanks.
btw, i think the nx274 is too big, no?

83 Crossfire TA

iTrader: (2)

What makes the best blower cam depends on the rest of the engine combination, most specifically the head port flow but also things like the amount of boost, bore/stroke, intended use and powerband… No one can really tell you that x will be better then y without more info then what we've got now.

FWIW, I believe that for the most part the comp lobes are a better design (from a power standpoint) then the crane lobes, and Comp appears to have more flexibility in their available lobes (crane doesn't really provide enough info for someone to make real choices, they do make a few decent cams, but they are hard to compare to others and even to other cams in their line)

Justin 87 GTA

iTrader: (3)

well, then i guess i should stay w/ the XE268-h.

Just for the record,..My car has a superam,.. 58mm tb, 355 w/ around 8.3:1 compression. trick flow 2.02's that I am porting now,..TES 1 5/8" headers,. vortech s/c w/ 8-12lbs intercooled boost. 700-r4 w/ 2,500 stall,. 3.45 rear gear,. 3,400 lbs car,. i want it to "Maybe or Hopefully" pass emissions with tuning,. drive and idle, run well, brakes to work good.. pull from 2,000-6,000, make good power on the street and pull hard at the track,.. I want 115 mph atleast w/ 8lbs intercooled. i hope to hit low 12's easily, and 11's w/ tuning and traction. not use what else i can say, but that cam sounds about right for all of it. It may even sqeek by on the emissions because it has low lift (under 500). that's about it . it's a weekend car, i won't be driving much,.. and i like the low end that the old setup had, but i still have 3.45's an a low first geared 700-r4. that's all// thanks

83 Crossfire TA

iTrader: (2)

Woohooo, some details.

OK, FWIW, I think that you'll run your mph with any of the cams we've discussed.

I'm not sure that you'll pass emissions with a bigger cam then the XE268H (I'm assuming -10, not -12 or -14). It is possible to pass emissions with a bigger cam, but it would take a bit of work and everything else would have to be perfect so I wouldn't recommend it to someone unless they like to live on the edge. Also, if you want to run a bigger cam you'll need much more converter, more gear, more everything to make it really happy.

Really, you should choose your cam after you have the heads done. If you can get your TFS heads to over 230cfm at .4-.450" lift and the exhaust to close to 90% of that at the same numbers then that is the cam that I would choose. If you only get your exhaust to 75-85% of that I'd look at something like the NX262H-13 or the NX268H-13. If you don’t make that flow on the intake of don't get at least 75-80% on the exhaust do it again, right…

What's behind the TES headers? That is going to effect your choice also. If you stick with the TES or if you don't have a great exhaust after then then you'll want to look at the NX cams even if you get your exhaust port flow up. If it was me I'd look for something a little better then the TES headers, since I've never been impressed with their design and they will be a bottle neck with any of these combinations.

If anything, I'd err on the small side with the cam and look for all the exhaust flow that you can find with the rest of that combination. That will be your key to a happy engine (the parts that you have now and the smallest cam should run your number, the closer you come to what I've listed the happier you will be)

F-BIRD'88

The Crane cam is ground on 114degree centers.

less overlap, dual pattern, long exaust duration. (blower friendly) Nicer idle too.

The stock FMU is going to need recalibration anyways.
the engine is going to behave differently than a stock motor. Plan on some chip tuning for a EFI system.
(of the two, the Crane is the most EFI chip friendly thou)

The Cranes' seat duration is measured at a different reference point .004" than Comp Cams .006"
so the duration appears longer relative to the .050" durration. But its not..... Both are modern fast action asymetrical high lift lobe designs.
If measured using the same lift reference they are more simular, than different.

You can get a simular Comp Cam ground on wide lobe centers
but the Crane is "Off the Shelf" and a proven performer.
Especially in a moderate street blower application.

it has the characteristics you're looking for.


There is much more to a sucessful camshaft design than just the seat, .050" duration and peak lift numbers found in the catalog.

Try it.

Justin 87 GTA

iTrader: (3)

83 crossfire,... first of all,.. i will be welding a better exhaust system up in the future, and switching to slp headers (1 3/4"),.. so that is not a concern. As far as the heads go, I am porting them by myself, so i will not be able to test them,..unless the guy can see what they do when he does the 3 angle valve job. And what do you make of what f-bird'88 is saying about that crane cam,...cause you guys are confusing the heck outta me. Is that a better grind,.. maybe you guys oughtta fight it out,..lol.

F-Bird'88,.. what you are saying makes sense,.. but i'm confused, is the xe268-h milder than the crane grind? or not? also,. I meant cpu not fmu,...lol.

I am liking your're both saying,.. but i have to say that i am leaning towards the comp 268 w/ 114lsa ,.. but I'm confused a liitle about if it is a good blower cam or not,...It seems that's not what it is designed for, but it does have the right numbers. I'm a little confused with the huge split in the lift of the crane cam. Not to mention,.. i'm not sure how to compare the two. Again, i'm probably beating this to death,... and it probably doesn't matter much either way,.. so i'll probably go with the comp cams,,,, unless you both agree otherwise.

thansk for everything,.. helping me learn,...thanks:hail:

Kingtal0n

I would go with the comp grind...

N/A they made 342HP @ 5000 rpms with the 268... with your super-ram tuned more for midrange they would have made even more torque..

top that off with you have a blower and they dont... widen up the LSA to 112 to help your torque even more and reduce nasty emmision and self-egr effect...

I think its a great cam choice for your combo.
Remember hes running a flat tappet cam, faster ramp slower peak.. with the XE comp grind and those heads which should flow something nasty for a street head, it just all matches up.

The only thing is i wouldnt go on a 114... he has a centrifugal not a roots so the little extra overlap is only going to help up top, and down low... hes not building insta boost like a roots would, so the 114 is really un-necessary... plus he has midrange gears and midrange stall... i think 112 would be better... its more midrange like the rest of his combo. its not a wicked duration so its not going to affect the idle quality much either...

top that off with hes probably going to hit it with 12PSI of boost.. i think a 112 would save the head gasket in case of an FMU incident.. or a fuel pump screw up or something... more headroom for cylinder pressure spikes... follow?

heck i ran a XE262 on a 110 in my 350 with a roots blower, and a XE262 on a 114 in my 383 with the same blower... and beleive it or not the 350 with the 110 LSA just felt better all around.

83 Crossfire TA

iTrader: (2)

My $.02, I don't really thing that the normal SLP 4:1 headers are much better then the edelbrock. Really, as unpopular as this is to say, I probably prefer the edelbrock headers to the SLP's, the only real advantage the SLPs have is that they are stainless. Their collector layout pretty much negates the advantages of the larger tubes. OTOH, if you were to find a set of older 4:2:1 SLPs then go for it.

Again, my $.02, I'd finish porting after the valve job since there is more to be gained in blending the bowls into the valve seat area then just about anyplace else on a set of heads, unless you've resigned yourself to completely reshaping the ports.

1- I don’t like crane cams… well, with the exception of the few that they grind for GM (and if the rumor is true the Lingenfelter cams)
2- I think that a 114 LSA is a mistake without going with significantly larger lobes and I wouldn't guarantee that the larger lobes would pass emissions. That cam with a 114 LSA will kill a lot of your midrange, where you're going to be relying on the motor to make power, but will help make power past the rpm range that you intend to run. I stand behind what I implied earlier. The only way that I'd run more then 112 LSA on a cam this mild in this application is if you end up with some REALLY CRAPPY exhaust side flow. (to be honest this is a much oversimplified view here… the real question is the timing events and the amount of overlap, LSA really doesn't have that much to do with it)

I don’t have their catalog sitting here (I do have all the comp lobe specs sitting here), but if I remember right it's bigger advertised and similar or slightly smaller at .050".

When it comes down to it they'll probably both run very similar times at the track and put down similar dyno numbers (we're probably arguing about less then 10hp either way). The reason that I'm leaning toward the 268-10 or -12 is that I think that it will be more fun to drive, it will feel better.

I'm curious, have you called both companies and asked what they would recommend? (if you have post it)

Justin 87 GTA

iTrader: (3)

I will call the companies tomorrow.. It seems as if the two of you both agree that a xe268 on a 112 is the way to go. So, i will call the companies tomorrow an re-post the results.

Just curious though,.. how does the lower 112 lsa on the same 224/230 duration affect the cam? I understand it'll increase midrange and allow for some bleedoff over the same 224/230 on a 114,... but does lowering the lsa to 112 change the way the cam was designed to work as a 114? Are we re-engineering it? thanks men.

83 Crossfire TA

iTrader: (2)

You're just changing the location of where the lobes are on the cam (mostly relative to each other). By shortening the LSA you open the exhaust valve later to better take advantage of the residual pressure in the cylinder (important with boost since you end up with more pressure late in the cycle), and open the intake valve sooner which helps with scavenging (assuming that you've got sufficient exhaust flow for the amount of extra exhaust you get with boost to get scavenging)

Justin 87 GTA

iTrader: (3)

But when you change the lsa relative to the grind, doesn't this in essence change the charicterristics of the cam? You know, relative to the design? And by redesigning it,. does it hurt the research that they spend tons of time on,.. how do I know that the cam will be better and not worse.

antoine

I HAVE THIS CAM FROM COMP CAMS THAT I HAVE INSTALLED IN MY MOTOR 510/510 LIFT 220/230 DUR WITH 114 LSA

B4Ctom1

REALLY? YOU DO? YOU REALLY SHOULDNT MAKE POSTS WITH THE CAPS LOCK ON. TYPING ANYTHING IN ALL CAPITOL LETTERS IS THE SAME AS YELLING!

antoine

cap lock was on i was at work but what is the big deal about it

Justin 87 GTA

iTrader: (3)

it's okay, can we please get back to the topic,. thanks,.. work was busy today, couldn't get a chance to call cam company.

Justin 87 GTA

iTrader: (3)

okay, comp cam recommends:
226/236 @ 050 480/489 lift on a 112 lsa,...it's a marine cam lol. but they say that's the one. what do you think? thanks.

83 Crossfire TA

iTrader: (2)

What lobes are those? The only 226 lobe that they list in their catalog is a magnum lobe, but the lift would be .464" with 1.5 rockers.

It looks like they picked something that is almost an exact middle ground to the cams that we've discussed. I think that will work fine, like I said before, I don't think that there is enough difference between the cams we were discussing for someone to really tell an extreme difference between engines equipped with them.

If those are not the XE lobes then I would suggest that you pick the closest XE lobes and do the same with them (224/236/112), and you'll basically have a 268 intake side (emissions and low end), a 274 exhaust side (longer exhaust duration to compensate for any exhaust deficiencies without severely effecting emissions/low end), and a 112LSA which we've already discussed. The reason that I would lean toward the XE lobes is that they have a shorter advertised duration with the same .050" which is a little harder on your valve train but will make the same power with a better low end, smoother idle and more emissions friendly. You'll basically end up with a hydraulic flat tappet copy of one of their XE hydraulic roller cams (how's that for the ultimate compromise? ).

Damon

[Damon walks back in, returning from an extended smoke-break...]

Oh, hey, guys, you still at this cam stuff? OK, cool.

Long story short- you're REAL DAMNED CLOSE in your cam choice. None of the cams you're considering is going to be much better or worse than the other.

My XE268 cam is the one ground ona wider 114* LSA for TPI/late model EFI engines (it's still just a plain old falt tappet cam, though). No, it's not really a blower cam, but the specs look about right for a blower. It works real nice in my blower motor, too so it passes the "reality" test with flying colors. The Comp cams Nitrous HP cams would probably make similarly good blower cams. The "standard" 268XE that everyone is familiar with is the same cam as mine ground on a tighter 110* LSA for N/A carbureted applications.

Are Comp XE cams more aggressive than a similar Crane cam? Maybe just a smidge, not much. I have used both and the Comp is really just a slightly bigger cam that it's specs would imply by virtue of where they quote their numbers. F-Bird is right about that. Nonetheless, the Comp XE still has slightly more aggressive lobes than the Crane when all's said and done. And it has the valvetrain noise to prove it. Trust me on that.

LSA of 110, 112, 113, 114? For a centrifugal blower something in the 112-114 range would probably be a good choice. For a street blower engine it's important to minimize overlap in order to TRAP BOOST in the cylinder. Efficiency will get you further than trying to "brute force" it wth higher pulleys. Most street blowers start running out of lungs at high airflows (roots or centrifugal) and having to pulley way up to get desired boost against a long-overlap cam starts to become a losing proposition pretty quick. If you got a real screamer with a big blower on it- who cares? You got plenty of airflow from the blower to overcome a cam with big overlap in that case.

Don't be afraid of massive differences in intake/exhaust duration with a blower cam. They work just peachy despite the fact that the specs would looks a little "odd" for a N/A application.

You're close on this. Close enough you'll like the results from ANY of the cams you're considering.

Justin 87 GTA

iTrader: (3)

okay, well thansk for the imput,.. probably going with the 224/234 on a lsa of 112 w/ 480/489 lift,.. comp marine grind. thanks

F-BIRD'88

read Damon's post again,,,, Clue = valvetrain noise.....let it sink in... then, buy the Crane Cam.

SATURN5

Hell my Malibu could suck a valve out the pipe and into a tree next door before you would hear any noise... at least from the valvetrain..

All cam mentioned are just a tad larger than the one in the Malibu. summit #1103. 214/224 445.450. on a 112. Not a blower specific cam.. but works real good on the 305. BW

Justin 87 GTA

iTrader: (3)

f-bird, are you saying they are too noisy,.. or something worse? i don't mind the noise. I had a noisy crane cam before. what aboput the specs,.. i know you like the crane grind,.. but i'm not too comfortable with crane, they don't seem to have as many choices. i think comp is a more advanced company, just go to the website.,... maybe i'm wrong,.. not trying to start a fight, but comp cams even has a 1800 number.

83 Crossfire TA

iTrader: (2)

Huh… I've never heard any noise from an XE cam (at least not more so then stock). You sure that you had it the valves adjusted right? Maybe I'm just deaf…


Did they give you a part/grind number for that cam? You’ve listed 2 different sets of numbers for it and none of them really match any of the comp lobes, and none of their marine cams have that kind of split between the intake and exhaust (but all are roughly in that range or smaller with a 110LSA).

Damon

Some people get noise from the Comp XE cams, some don't. I happen to get noise from mine and I've adjusted the valves six ways from Sunday. I also run 1.6 rockers on mine (which Comp does not recommend) which probably makes the noise situation worse. I also use some fairly stiff valve springs (little stronger than the recommended Comp valve springs for the cam). That probably affects the noise level a little, too. I've now run the engine for over a year like this (weekend car- not daily driver) and nothing has broken/bent/worn out in the valve train so I accept it as normal for my combination. I don't recommend my valvetrain combo for a true daily driver. Stick with the recommended springs and 1.5 rockers.

I have never had a noisy valvetrain with a Crane cam, regardless of springs or rocker ratio.

This is the first engine I have built for myself with a Comp XE cam in it. I ususally use Crane cams and I have nothing but good things to say about Crane. The specs on the Comp cams always look better on paper but 99% of the time my engines somehow end up with a Crane cam in them.

Crossfire- was your question about cam part numbers directed towards me? I can find the parts numbers for all the cams that have been referred to by various people in this thread if you like.

Justin 87 GTA

iTrader: (3)

i'm sorry, i was me,i have so many specs, but it's a 226/236 @ 050 480/489 lift on a 112 lsa. the part # is definately 12-240-4. some guys on ls1tech.com are sayint that it's too much of a split (especially for emissions),.. and that i should run a smaller duration cam on a 114,..(like a 214/220 @ 050 or a 220/226) so it passes emissions and it makes better power up top. i don't think they understand my combo like you guys do and i don't think they read my post thouroughly. They may have too much ls1 experience which may not be as relative to my setup.. anyway it is a marine grind. then get this,.. i called Lunati,.. they recommend a 205/215 @50 427/453 ona 112,.. lol too small right? and crane reccomends the 226/234 part # 11-38-22. my head is spinning.
I'm really just about to just go and order the 226/236 480/489 on a 112 lsa.. i think you guys are right,.. it'll help w/ midrange,.. I'm just worried that it's too big to run correctly and hopefully pass emissions,.. and the damn knock sensor may retard..maybe the LPE 220 that is 215/220 510/510 114 lsa?? LOL

83 Crossfire TA

iTrader: (2)

heh… weird. I usually run Crane Gold 1.6 rockers with my comp cams, and the only springs I like are some of the comp springs (the 10308's for aluminum heads, off the top of my head). I guess find a combination that works for you and run with it.

Nope, I was confused about the numbers that Justin was posing, since they didn't match comps catalog or each other.

My $.02, if anyone answers the question relative to what works with an LS1 ignore that, LS1 heads are significantly different then anything before and act more like 4V OHC engines then traditional SBC's. The over simplified version is that they have better exhaust ports and do not need nearly as much exhaust duration to accomplish the same thing (as a matter of fact a cam comparable to most NA SBC cams in an LS1 will have a reverse split in an LS1, less exhaust duration then intake).

Huh… I don't think Lingenfelter sells a bad cam, so you probably wouldn't go wrong there.

Based on everything else here I'd go with the marine grind and be done with it. You won't be sorry.

Justin 87 GTA

iTrader: (3)

wel,, then that settles it,.. the marine cam it is 226/236 480/489 on a 112,.. The LPE is too expensive,.. and i would get the LPE cam ground custom,. but who knows if those are the "real specs" on the LPE.
Anyway, i really have to thank all of you for your imput and help. I have to say i learned alot, and I feel comfortable with the choice now. Not to mention, they have a "k" kit with lifters, valve seals, timing chain and gear, springs,..etc,.. for about $369,. not too bad. thanks all. -Justin

B4Ctom1

that sounds really nice

83 Crossfire TA

iTrader: (2)

I've had the exact same thoughts about the LPE cams… way expensive and the power bands and #'s they get from them don't match the published .050" duration numbers that they list. I would love to see what they actually measure (there is a machine that actually "reads" lobes) and who really grinds them (like I said, the rumor is Crane).

Justin 87 GTA

iTrader: (3)

yeah, I bet it is a crane cam...but i'm not paying LPE prices. I'll just stick with the 226/236 480/489 on a 112. sure it'll work well. maybe even better.

F-BIRD'88

The LPE hydraulic flat tappet cams appear to be
generic performance grinds. Could be actually manufactured by any number of camshaft manufacturers, including Crane cams. They work,,, just have to bolt them on a real motor.

Justin 87 GTA

iTrader: (3)

I just got in contact with the lead cam designer over at crane. He suggests a 224/230 @ 050 503/510 on a 112lsa. which is very close to the XE 268, just with more lift. ,... and not so big of a split on the duration as the 226/236,... So this is actually the one i'll get,.. i think it's perfect.

83 Crossfire TA

iTrader: (2)

I'd bet that you'd see less then the margin of error on the dyno between those 2 cams, the comp would probably make slightly more with a marginal exhaust where the crane would be slightly smoother, better mileage (slightly) and make the same power with good exhaust

Pick which ever one you're more comfortable with

Justin 87 GTA

iTrader: (3)

i got the 224/230 477/480 on a 112 (comp cams)... just thought i'd let you all know,. so this topic is considered "kicked" and if anyone needs to do a search there is a lot of great info in here. later,.. and thanks.