We're doing some theoretical bench racing over at ne3g, and a lot of great information has surfaced, but it seems that the general consensus is that I'll never get out of the 13s with a hydraulic cam. I'd love to swap to a roller, but I'm looking at close to a grand including the cam price. That's a ton of money for a cam. I want to see how much of a difference it will make. Everybody is basically telling me that heads are a waste of money without going to a good roller cam.

I threw this in the TPI section because that's what I'm running, and it seems that TPI responds well to valves that can open and close as fast as possible.

My plans are for an accel base and SLP runners. I've got forged flat top pistons and 461 fuelie heads.

So... what's everybody elses opinion?

 

I would like to know the answer to this too. Because the guys at TPIS are telling me that there is a huge difference. One guy told me that they tested two identical cams except one was roller and the other was not and they noticed like a 20-25 horsepower gain with the roller setup. I find this hard to believe, but who knows.

 

Well I converted my 400 to a roller motor. And I would think that the gain would be even more than 20-25. If you get a chance get a roller lifter and a flat one and any old cam then run them over the cam lobe. The roller will go so easily its amazing. Now imagine the flat but think when it has the valve springs its pushing against how hard it must be for it to go over that lobe.

Big added bonus: No cam break-in time either

 

The largest difference isn't even the friction, it is the cam profile you can run with the roller. With the roller you can ramp up to you max lift figure quicker, and the max figure can practically be higher. Just look at specs for similar duration profiles, and notice the difference in lift, and also know it hits that max figure much quicker. I have never seen a roller cam with identical specs as a flat tappet, that negates half of the reason you run one, so that is BS from TPIS (what a surprise). I have seen many cars with flat tappets in the mid 12's, so i don't think it is a brick wall, just harder. The roller is a better way to go, but you can hit 12's without it.

 

True that is one of things that made me lean towards the roller cam. I didn't like any of the lift numbers of the flat cams.

 

Ok I ran the numbers in Desktop Dyno 2000 to see if we could get an answer for you. I ran the three tests. One is the engine in my firebird with the hydraulic roller cam. 2 the only thing I changed was the tappet type from roller to flat tappet. the engine lost 20 hp/ and 50 lbs/ft at peak. Even more down low.
The third test I ran i went to crane cams and got a hydraulic flat tappet cam with the same duration specs at .05 (it's a pretty big cam (234/242 @.05). and used all it's specs. I can't seem to get the graphs posted so I'm cutting and pasting the tables. Now we all know that software isn't totally accurate, but the changes here are huge (though I'm guessing the differences would be less with smaller cams) so I think we can get a fairly clear picture of the answer. BTW these numbers are naturally aspirated, with nitrous they go way up . Hope this helps.
John
Oh and if you want to see what this combo can do in one of our cars I posted it at https://www.thirdgen.org/techbb2/sho...threadid=88495
Hydraulic Flat Tappet.

RPM HP TQ
2000 126.111473 331.042633
2500 169.609314 356.179535
3000 212.796982 372.394714
3500 268.640839 402.961243
4000 325.309723 426.969025
4500 381.135254 444.657806
5000 423.928650 445.125092
5500 448.325836 427.947388
6000 456.073669 399.064453
6500 447.537262 361.472412
7000 414.550354 310.912750
7500 386.384033 270.468811

Hydraulic Roller
RPM HP TQ
2000 167.372910 439.353882
2500 217.768875 457.314636
3000 272.550079 476.962616
3500 333.229706 499.844574
4000 392.898895 515.679810
4500 446.319519 520.706116
5000 485.473969 509.747650
5500 499.354645 476.656708
6000 487.633392 426.679230
6500 460.970947 372.322693
7000 420.017487 315.013123
7500 377.445435 264.211823

 

Just outta curiousity, how do you figure $1000 for a roller cam setup? I Just got the stuff to convert my old style block over to roller (retro-fit) and it wasn't anywhere near a grand. If it was then it would've been way out of my budget.

I just did a search on SummitRacing.com and found the following:

Retro hyd roller cam 239.95
Retro hyd roller lifters 304.95
Retro hyd roller pushrods 35.95
valve springs for above cam 82.95

That's just a bit over $600.

You could also do like an LT4 Hot cam 175.50

The LT4 Hot cam would save you $65

 

Advantages of roller cams:

(1) less friction

(2) less heat, because of (1)

(3) the energy that would be spent creating the heat in (2) is now available to accelerate the car instead

(4) for any given duration specs, the roller cam will spend a LOT more of that duration at full lift. More time at full lift = more airflow = more power at high RPM.

(5) no worries of wiping a lobe on breakin, wear becomes a non issue.

What all this means to hot-rodders like us is that the roller cam will let us make more HP without sacraficing drivability. And yes, the gains can be rather substancial.... For a given idle quality (mostly determined by seat-to-seat timing of the cam events), you can get a LOT more lift and duration from the roller.

However, heads are certainly not a waste of money just because you don't have a roller. Both are helpful to an engine and they work even better when used together. Last time I checked, NASCAR winston cuppers use flat tappet (albeit non-hydraulic) cams, and they can make 700hp on the non-restricted 350's.

 

Depends on brands. You picked out the cheapest of everything, and every time I do that, I wind up breaking stuff.

With an expensive cam, quality lifters pushrods and especially springs capable of over .500 lift, along with the cam button, new roller chain set, it starts pushing on $800-$1,000.

 

Well.....I guess my Comp Cams XE270HR cam from Summit is a cheapie then, as that is exactly what I priced out! I looked up the cam and followed what they recommended for the roller lifters, pushrods, and springs. Hmmm.....I always thought Comp Cams had quality stuff...learn something new everyday.

 

Well, I looked up all crane stuff because my issue of summit doesn't show anything from Comp except for a couple camshafts. My point is, prices will range from $600 and up. $600 isn't the average. And if I want a good cam from Accel, LPE, TPIS, etc, I'm going to pay through my cornhole.

 

Why do you think a cam from Accel, LPE, TPIS etc. must be better? because they cost more?

comp and crane are two of the biggest names in cams out there. Half of those companies you mentioned probably have their cams ground by crane or comp anyways. crane and comp both have a very wide variety of profiles and choices and your engine won't know that you didn't buy the cam from TPIS anyways....

$600 may not be the average for trendy "designer" cams, otherwise 69TPI383 has a valid point.

comp and crane ARE good cams and equipment.

let's compare for ex. the TPIS zz9 cam vs crane 119821
TPIS: 212/226 @ 0.050, 0.483/0.520 lift, 112 lobe sep
CRN: 214/222 @0.050, 0.488/0.509 lift, 112 lobe sep

now...i bet you that you probably won't even notice the difference in these two cams. maybe a few HP, and it's hard to say which one would make more power. not worth the extra hundreds for the designer TPIS name.

BTW the crane cam is $299, hydr roller lifters that crane recommends, $379, recommended springs $88. total $767. Way closer to $600 than $1000.

You could also use the comp XR269HR which is 218/224 @ 0.050, 0.495/0.503 lift, 112 lobe sep, and STILL probably not notice much difference, and that cam is only $239.

the money you save is better spent on headers, head work, better intake, etc., and you will get lots better return (HP) for your investment ($) that way.

 

Hmm, I was just on the Comp Cams site and it said 42 of the 43 cars in the 2002 Daytona 500 had Comp Cams in them? Must be Ward Burton's Dodge had a TPIS cam in it thats why he won. HAHA I could probably get someone to charge me $1,000 for a cam itself but that isn't going to make it better than one that costs $250 etc. I suppose since what costs more is better, that Jim85 better get rid of the IROC and go get a Corvette since it costs more.

 

why not just get a Custom cam from Comp cams that way you can get what you want. I just did it cost exactly the same as a regular cam. all you have to do is call Comp cams and get a grind number then call Summit or whatever and give them the numbers all it takes is another week.

 

Yeah.....and it was ground for TPIS by Comp Cams

Sorry.....I couldn't resist....I'z just razzin' ya

 

Christ! I'm not trying to say that more money = better performance, but of course that's what everybody needs to immediately assume. Comp and Crane may be the biggest cam makers out there, but that doesn't necessarily mean they know that works best with TPI. Accel and TPIS eat breathe and sleep TPI so it stands to reason they may know a thing or two about it. The ZZ9 camshaft continuously outperforms other grinds with similar specs. I'm not saying that the other stuff is crap, but immediately discounting the more expensive stuff is just plain dumb.

 

What we are trying to say, and it even says it in the TPIS book, (Insider Hints maybe) to go for the cam first as it's going to give you the biggest improvement. Goods heads are nice but a better cam can help a set of heads flow more by opening the exh longer for instance.

If you're looking for that last bit of HP so you can race, then maybe the roller from TPIS is what you need. If it's for a daily driver or occaisional weekend blast, then you're not going to notice that extra few HP the TPIS spec cam *might* make. Especially not $140 worth of differance. I have the TPIS catalog and the Insider Hints book. I have the Accel catalog. In my opinion, there's not enough differance in the cams to justify paying the extra $140 over a quite simular cam costing hundreds less. TPIS cam $379 Comp Cam $240 GMPP LT4 Hot cam $175 Unless you put that engine on a dyno you couldn't feel the differance in each one of these cams. Thats all we're trying to say....no flames intended.

 

this what I paid for my retro kit:

$300 for retro-fit lifters
$100 for retro-fit pushrods
$240 for custom cam