No, those were just some files he sent me overlayed against a FAST and stock LS6. Wether it's big enough or not, it's still far better than the FAST. Their showing over 70rwhp gains against the FAST 90mm on 427's. I'm not sure of which size they were. He obviouslly reccomended the 55mm version for me. You have to figure 8 55mm TB's is always better than 1 90mm. Not to mention the kinda cams you can run and still have great driveability. I'm personally looking at something like a 108 LSA w/ 104 ICL.

 

Street car or race car? 108 probably won't make a very nice street car.

Just to add another wild card: how about a smaller, emissions cam with a supercharger? You could make more power and be emissions legal.

You would need a blow off valve, however you would have very sharp throttle response.

If going this route, you probably want to start with slightly lower compression.

P.S.
This is a pretty expensive motor (big heads, Jesel, Harrop), what are you doing for the bottom end? I would have either Callies or Crower make up the bottom end: either Crower dihedral light crank and maxilight rods or calles magnum xl with carillo rods. In either case a custom CP, Wiesco, or J&E piston. Tool steel pins. The crank manufacturer will build and balance the crank for the correct bobweight. Probably should specify a no-hole balance. I like the Callies induction hardening of the crank, however I prefer the design of the maxi-light rods and some of the details on the Crower crank.

Either could also whip up a set of Ti rods for another $2k or so, probably saving 150gms/rod at this power level.

 

I did the VE on that 262/272 cam and the IVC is 56 degrees ABDC @.050, my 243/243 (LSK lobe .653" lift) 114 LSA/ICL has a IVC of 55 degrees. My motor hits Peak torque at 4800 and peak horsepower at 6200, so it looks like your calculator is pretty close in terms of peaks vs. rpm. The horsepower peak may be hitting a ceiling, (it flat lines to 6500) by running out of flow thru the Fast 90, with the Harrop I would probably see a higher rpm hp peak.

 

The solid will have more area under the curve when compared to a similar at .050" duration hydraulic. This is where the added power comes from and will come all througout the power range, not just up high. To take advantage of those heads you are going to want to lift that valve as high as you can while still remaining in the realm of what you deem good spring life and not tearing up valve train parts too much. Remember, valve train deflection will keep you from seeing the lift at the valve that you get on paper by multiplying lobe lift by rocker arm ratio so add that into the equation as well. MaxRaceSoftware (I believe Larry Meaux) over on speedtalk has hit on this point a few times (http://www.speedtalk.com/). Go over and do some searching over there for more info on this subject. My heads don't flow like yours over .600 and I'll be over the .700 range with a smaller motor and not as good intake.

 

The motor is going to be for all out N/A performance. I've done the nitrous/supercharger thing before, and there are to many things to jack with in both applications. I want to be able to throw the motor in and hit 650 rwhp whenever I want. No worries about belts, pullies, nitrous bottles, etc. cluttering up the bay or inside the car. The bottom end consists of a Lunati Pro-billet 4.185" stroke crank, SCAT H-beam rods, and custom scanned Wiesco pistons (-13cc's). Block is a dry sleeved RED, LS2 w/4.150 bore. I went with the longer stroke for the added TQ on the street. Guys with 346 (3.898) stock bores run 230 cc heads all year round. There is no reason why a 4.150" bore, 454 cubic inch motor can't use a 265cc head. I know a solid will maximize "area under the curve", but why wouldn't it? It's a very harsh lobe. Duration under the curve is greatly maximized, plus you've got solid parts in the valvetrain. The good thing about the ID TB intake is that your driveability is greatly improved. Cars in Aussie run 106 LSA's in grocery getters. The 108 LSA, should be a whim to drive on the street. I'd probablly compare it to a 112-113 LSA with a LSX manifold. The larger duration (259/263 .663"/.663" 108LSA 104 ICL) will give me the max amount of vlavelift under the curve that I can get out of a hydraulic roller, and still keep the DCR around 8.3-8.4 depending on my SCR, which should end up around 11.6.1. It's my thinking that this cam will maximize what I can get out of a hydraulic applcation, keep my power band in a useable range, and still provide good driveability.

DAPSUPRSLO, I understand exactlly what your saying, but, in your applcation, you have the intake as a limiting factor. You will maximize your under curve power, but with the smaller cubes, it'lll want to rev, which it won't be able to, because it is intake limited. The motor will peak far before it could because of lack of being able to get the proper amount of air. So, I ask, why would you want to limit yourself in the intake department? Kinda like ya'll asking me why I would limit myself in the cam department?

Keep this stuff coming guys, it's very informative, and I'm enjoying the conversation.

 

How do you like the cam in your car? Seems like a +4 advance would have worked nicely in that combination, espeacially with a heavier GTO.

 

I like the cam a lot. I may try and advance it a few degrees and see what it does. But with the big cubes I wanted a hp peak in the low 6k rpm range and this worked out well for that. I am also running cats so I wanted to keep the amount of overlap manageable.

 

To really use .7+" with spring reliablity, a 2" tall 1.5+" diameter spring is needed.

Cary, Craig, don't the ET heads support that?

 

That's another thing with solid stuff. The price goes up to have a solid valvetrain. With a set of heads that were already $5k, I wasn't really interested in spending any more.

 

Per your post #20, be interested in what Engine Analyser makes of the following specs David. (No vacuum limitation or mufflers, etc.)

I used the Harrop 55 mm intake in a Dynomation sim for a 7.0 L. all-out road race engine with ET's 240 cc C5R heads , 0.750"/0.630" lift, 276/284 @ 0.050", 114 LCA solid roller cam, 14:1 CR, 2.0" to 2.2" ID stepped headers and Burns-style collectors. The estimated power from the very first shot was far enough over 800 HP @ 7,000 RPM that I won't be specific for fear of being jeered off the thread.

I should know within the month if the customer will build it; he threw out the approximate specs but was expecting 'only' ~ 720 HP and now may choose to go much more conservative. )o:b

 

The individual tbs shouldn't affect behavior with overlap. 108 with the those lobes (309 and 313 @ .006") is 95 degrees of overlap.

If you insist on hydraulic lifters (and you can always change that), you may as well use the biggest lobes on both intake and exhaust. You may be happier retarding the cam a little...say 263/263 110/+2.

 

I using Performance Trends Engine Analyzer Plus. There Engine Analyzer Pro is better, however I've never felt my need justified the price.

You have program that can model a merge collector? Those numbers look very reasonable for that spec. Big solid cam, lots of lift, high compression. I'm getting 774hp @ 6500 rpm for it, but could have some of the specs wrong. Very flat torque curve from 4700 to 6500, with only a slight (15%) drop to 7000. Playing with intake runner length and diameter can get it over 800, at some loss of low end of the power curve.

I have to go back to work now.

 

It may not seem that a intake would change the way the car idles/operates, but in this instance, it does. Driveability is greatly increased with ID TB's. J-rod had lots to say about it in another thread, but since the search is down, I can't explain "why" it does. This thread had a bit of info, and a video of a 242/242 106 LSA idling like a stock car. https://ls1tech.com/forums/generation-iv-internal-engine/350199-ls7-c6r-velocity-stack-induction-injection.html

As for the cam selection, increasing the intake duration and subtracting th eLSA and IVC are going to drastically decrease my DCR. The specs you have above would drop me to 7.7 DCR, when I'm trying to stay up around 8.3-8.5. Plus I wanted a little extra on the exaust duration incase my exaust became a hindering factor. The biggest header I can get on an F-body is the Kooks 1 7/8 stepped to 2", which is what I have. If I can fit a 3 1/2 inch X-pipe exaust under the car, I may not be as worried about it. It's possible that I may just stick with the 3" X system though.

 

I'd like to see that video. Do you know which 242/242 cam that was?

As a few different threads running around today indicate, a more aggressive cam can have less overlap with more duration at .050. For example, a 242/242 106 Xtreme Street Roller would be like a 238/240 114 XE-R.

I'm not sure how DCR varies over cylinder size. However, the tool I'm using seems to prefer a later ICV. Arount 88 ABDC.

 

David, I don't know what kinda lobes they run in australia. Although now that the search is up, you can look around at some of the threads on ID TB's. The australians love um. Some of the guys even called there 106 LSA cams "grocery getters". The ITB's along with speed density tuning is basically the best you can do. The reason why they idle better, and I'm quoting from a post by J-rod," Each inlet sees atmospheric pressure. Think of it as 8 separate 1 cylinder motors. No shared plenum. Idle and throttle repsose are better. Tames down a big cam too." Here's the video of the 242/242 106LSA.
http://users3.ev1.net/~black_ops/video/242-106.mpg

Your theory on the overlap is interesting. All the more reason for us to know which lobes they use in Aussie.

As for the DCR, I'm looking for an IVC of around 76-78 @ .006". Should make for some violent mid-range power.
EDIT: After doing some searching, it looks like the Aussies use the same comp lobes we do. They seem to be pretty popular over there. I also found a thread, that you started David, that had alot of good info on the ITB's.

 

Heard the video. Half the time he is blipping the throttle. The other half it sounds like 242/242 106. With XE-R lobes, that is 79 deg of overlap. 259/263 108 with LSK lobes is 95 deg overlap. For reference, the stock LS7 cam has 43 degrees of overlap.

Throttle response will be fantastic. The throttle plate is just a few inches from the valve. However, the overlap is within a single cylinder. What is the theory behind individual TBs affecting idle?

The overlap question is probably at the root of the LS9 being an SC engine. Clearly, there is 100hp on the table with the LS7, unreachable for emissions reasons. With SC, they can get the flow and leave the overlap low. In fact, it advantageous to leave the overlap low.

I wonder why they didn't spring for a solid cam. That would have let do 240/252 with similar lift and the same overlap and ICV (vs. 211/230). That would be interesting, a set of Jesel or T&D adjustable shaft rockers and a 240/252 119/-4 Xtreme Street Roller for High Lift. Might need a little more spring on the seat, although the lift is the same.

Compared to a 108/+4 setup, it has the same evo and ivc as a 261/255. Or 257/259 108/0.

 

Beast while those look amazing, how would one setup nitrous with it...?

 

If you wanted nitrous, you'd either have to run the air box that Harrop provides, which likley won't fit in a F-body, or go direct port.

 

You really think it sounds like a 106? Sounds like it's idling smooth as silk to me. I had a 230/242 112 XE in a LT-1 that would have shook that thing under the pavement. Then we have the argument that has been brought up by a few of the sponsors, including ET, that these more efficent heads don't need near the amount of camshaft that we are talking about to make power. Basically, A poor head needs more camshaft to over come the short fallings of the head, wearas a good head can utilize less camshaft to make more power.

 

Absolutely correct, the combination of intake, head, cam, and exhaust need to be what is needed to fill the displacement in the available time. The trade-off is between the short time available at high speeds, and the need to maintain flow/pressure differential at lower speeds.

For a given displacement, the better flowing head needs less. However (I love that word), the bigger head gets much of its advantage at larger valve openings. The 265 has minimal advantage at .5" (0-5%) and no advantage below that. At .7 the difference is large(over 15%). And the bigger port would have trouble achieving adequate flow velocity at low speeds, further hindered by high overlap.

What sort of profile does ET suggest for your application? With the Harrop intake, you will have one of the prettiest ET installations. And with a 454, pretty high numbers.