I'm going with the XR264HR-12, 211/219 @0.050, 0.487/0.495, and 112 LSA. I'll be running L31 Vortec heads with a SDPC base and AS&M LTR's.

Woohoo!

Hopefully this will be a good combination of parts and streetable. I'm hoping to give 12.9 a nudge when I build this setup in my GTA with 3.27 gears and the usual TPI mods, let me know what you guys think.

 

I would buy the lingenfelter 211 219. That cam is designed for a TPI. The comp one is not.

 

The XR264HR actually has 212/218 duration and .488/.495 lift. That is the cam that Comp Cams recommended to me for my LTR setup. It IS marketed as a TPI cam...I say go for that one.

I've since removed my LTR setup and I am now installing a Stealth Ram, so I went with the next larger TPI cam in the Comp Cams catalog...the XR269HR. It has 218/224 duration and .495/.503 lift. I'm using 1.6 roller rockers, so I have .528/.537 lift and slightly more duration (~2 degrees). I always stay on the milder side with cams as is recommended, so I think this was a good choice for me...Good luck with yours!

P.S. - Get a lower gear like a 3.42 or 3.73 to take advantage of the cam

 

Thanks for correcting me on the specs Scott

Yes its a cam designed for TPI.

 

Is it designed or marketed? Look at the differences in the cars with ling. 219 cams and ones with hot cams. In lies my concern.

If you do see many cars running the cam you chose and running well, by all means buy it.

 

Designed or marketed, thats a good question....

 

Cant beat The Lingenfelter 219!!! I know of 2 cars with that cam and they make 440 hp and 490 trq.!!! And run 11s!!

 

That Comp Cams grind seems to be very much like the Lingenfelter 211/219 cam, Seems to be a good choice for the LTR setup

Bob.

 

You cannot compare cams on their .050 duration and expect accuracy. Alot happens on the opening and closing of the valve. so, saying a cam "sounds like" or "is about the same as" makes that cam a fake. Now, if that comp cam is making cars go very fast that is a different story. Can someone find a 12 second car with it?

 

Gofaster, not sure what you are trying to say.
Earlier you were comparing the Hotcam to the 219 cam? Totally different animals are they not. The hotcam being a dual pattern 218/228 designed for short runner (LT1) cars and the "219" being a single pattern designed for the superram.

As far as the difference between the chosen comp cams cam and the 211/219 cam, I just don't seee a huge difference.
Yes the Lingenfelter cam is proven fairly well in LTR cars but its nice to see people be "pioneers" and try other combo's.

I'm not trying to be a smart***, just my opinion that's all.

bob

 

Ya but Kevin91Z has a Hotcam with SLP runners with 317RWHP..So I think there is power made with LTR's and a HotCam... I say put what you wanna put in... try it out this is what this board is all about trial and error..

 

Bob, you dont see a huge difference b/c you are looking at the .050 durations.

 

Seeing how well my LPE 219 works, along with a lot of vetteforum guys, and hearing of C4's running low 12's w/ the LPE 211/219, that is the only cam I would put in with a LTR intake. Nothing against the XR264, but like Gofaster has said, there is more to a cam than just duration @ .050", and the LPE 211/219 has more lift than the XR264 as well. Just make sure your valvetrain can handle the lift. Best thing to do is see what others are running with each cam in similar combos to yours.

 

The 74211 is one fine LTR cam, no question. The valve timing events are well matched to the long tubes. Too bad they won't publish the events.

Comp Cams does publish full specs on their lobes. The Extreme Energy lobes are about as aggressive as you can get right now in terms of valvetrain acceleration. The basic XR264 does have a little less exhaust lift than the 74211 but Comp has high lift lobes that you can custom order so higher lift isn't a problem if that's what you're after. Example, lobe number 3192 - duration @ .006 = 276 degs, .050 = 224 degs, .200 = 152 degs, lift = .567" with 1.5 ratio rockers.

DUI has made a good call with the XR264-12. Here's a comparision to the TPIS ZZ9, another cam that works well with LTRs. Intake duration of 264 degs at .006 is the same as the ZZ9 but it has 8 degrees more duration at .200 (133 versus 125). Exhaust duration of 270 degs at .006 is 6 degs less than the ZZ9 but just 4 degs less at .200 (139 versus 143). This shows that Comp is using "faster" lobes than the ZZ9. You'd expect that since the ZZ9 came out at least 5 years before the Comp lobes. Overlap at .006 is 43 degs for the Comp and 48.3 degs for the ZZ9. Overall conclusion is that the Comp will idle smoother and generate more vacuum with the same or better power. I also looked at three other hydraulic roller cams designed for TPI applications. All had intake durations between 264-268 degs at .006, exh duration of 274-279 degs, and overlap figures between 42 and 45 degs. Not one of them could match the XR264 in terms of duration at .200. They're all older technology.

If DUI does want to take a chance and does mind forking out a few extra buck then he can't miss with Lingenfelter. If he wants to be different and save some money in the process he's got options. I say he won't go wrong in either case. Finally, if anyone has used a degree wheel on a 74211 I'd love to get my hands on that data. No flames intended, just another perspective from looking at the data.

 

Mark has stated very well the main reasons I went with the XR:

1. Its current technology.
2. I saved a bunch compared to the 74211.

The XR264-12 was USD$125 cheaper than the 74211 from Summit, and thats around $250 in Aussie banana bucks. The specs are "similar" to the 74211, and thats also a reason a chose it.

I do need to get my heads machined for the 1.43 inch Comp Cams 986 dual springs, but the Vortecs needed a spring upgrade anyway so its not a big deal.

Anyway I'm excited and looking forward to seeing how this baby runs when I'm done

 

Mark,

Where did you get those specs for the ZZ9? I hope from an accurate degree wheel. TPIS seems to "fudge" their advertised data. The "real" specs are supposed to actually generate better results and have faster ramps than advertised.

Some of your data is unsupported. Saying that a faster ramp is higher technology is not well founded. What technology went into making the ramp steeper? For years racers have been making cams accelerate so quickly that the valve is "thrown" off the cam. This makes the near zero RPM checking for inspection show a lower lift than is actually acheived. Not for a street car; but not new technology either. Since the ZZ9 was designed 5 years ago nothing has changed in the TPI manifold design and IMO if that cam was a good cam then; its' value still stands. I personally do not like the ZZ9, though.

Since these Comp cams are newer technology, why dont they have asymetrical lobes? These allow a faster off the seat acceleration yet allow the valve to close softer making the valve bounce less when closing. To me this seems like a grand idea.

If it were my car, I wouldn't want to be the guinea pig. Who knows, maybe this comp cams cam is better than the 211 219. But if you want to experiment, all the better for others. Experimenting usually costs more in the end but benefits the TGO community.

 

Yes this cam could well be better than the LPE 74211, but either way I dont believe that "experimenting" is quite the right word to use. To say that this setup is some sort of "guinea pig" is perhaps a little extreme?

I'm not trying to build the quickest or most powerful 3rd gen in the world here, just something fun to drive on the street that can hold its own and earn some respect. I have absolutely no doubt that the XR264 cam will produce a very nice result with the LTR type setup.

 

Perhaps I was a bit extreme, sorry. I do think it wil be a good choice but may or may not be the best. That sounds better.

 

Gofaster,

The ZZ9 specs were measured by another TGO member using Cam Pro Plus on a cam he purchased from TPIS. These are the only numbers I put much stock in for the reasons you mention.

What I really meant about technical advancement is that the cam companies have been continually pushing the acceleration rates for street cams designed to go 50,000 miles or more. I agree with you that racing cams have always been fast but not very practical for a daily driver or street application. The point about 5 years advancement really pertains to valvetrain advancements since, as you point out, there hasn't been any changes to LTR TPIs since the aftermarket tubes and manifolds came out in the mid-late 80's.

I have no specific knowledge whether Comp does or does not use asymetrical profiles and did not intend to infer that I did. I'd bet that most cam manufacturers do use this approach for the reasons you mention.

In closing please don't talk DownUnder out of ordering the Comp cam since he's going to be my guinea pig. Jim, ignore this last comment.

 

:rockon:

 

I will be running the same set-up as in my sig along w/ the SDPC manifold and Vortec heads.

The cam I selected (vette guys have good numbers with it too) was the Comp Xtreme Energy 218/224 @.050 cam. I dont have the grind # w/ me but those are the specs. Lift is like .485/.503 or something like that w/ 1.5 rocker arms. The Vortecs exhaust flow #'s blow hence why I chse so much duration on the exhaust side. My vortecs will be fully ported along w/ the runners, base, and plenum as well.

 

I believe that is the cam that Traxtion ran a while back. AFR 's and LTR too got him into the 12's.

Bob

 

You are refering to the XR269HR, the same one I just bought for my setup. I listed the specs a few posts above this one...

 

I emailed Comp Cams about their use of asymmetrical cam profiles. Here's their response.

About 90% of our profiles are asymmetric. Basically there are regions on both the opening and closing sides that can be pushed harder without hurting dynamics and durability. To get the most out of a lobe it is usually necessary to make it asymmetric. However, very very few of our lobes are simply fast open and slow close. That was the original way of making asymmetric profiles and can be very ineffective. If you loose control on the opening side, you can never regain it on the closing side, and a fast closing intake is required to trap the maximum inlet charge and build cylinder pressure. On our designs, each segment of the lobe is studied and optimized to provide the best combination of power and control (and reduce noise on street lobes). Hence an opening side may be quicker off the seat, but the closing side may have more velocity at mid lift.

 

No, I have TPIS large tube runners.