455 performance... what next?

X2, big time! You want those on your car so you don't break the frame!!


Derek

 

Thank you. Is anyone reproducing this cam? The poston gs 118 looks very close too.

 

I may start a post called the putrid comp 268h.... protest to comp cams! Lol.

 

Thank you! Where does one get these braces?

 

Most of your cams in the red would be fairly detonation safe at your assumed compression
Better flowing heads will allow slightly more cam than what the printed specs suggest.

 

Here is a set with a picture of where they bolt to;

http://www.ebay.com/itm/MSS-Control...ash=item3a7b55fe7b:g:YoAAAOxyThVTaRRH&vxp=mtr


Derek

 

Ok, looked at more cams. I see the TA C118 is basically the KB C118.

 

Just got off the phone with TAperformance. They recommend using the TA290-94H and stage 1 springs for 9.0:1 compression or greater. He thought I would be closer to 9.0 with the 1970 heads. I asked about the TA c118, but he said that 10:1 or more is requested and my car would be lazy off the line with it.... but they didn't know I would change the converter.
He thought the comp268H was done at 4500 rpm.

 

Get a hold of Scott Brown from this site;

http://www.buyracingparts.com/

And let him know your combo with the JW converter and see what kind of custom cam he can come up for you. A custom from SB is only around $20 more than an off the shelf grind.

See if he can go in between the TA 290-94H and the TA C118. Both cams have 226 @ .050" on the intake but the C118 has 12* more ex. duration @ .050" of lift. If you go down to 224 on the intake and up to 238 on the ex. duration @ .050", it would make it milder while still getting the ex. the flock out of there with manifolds. That would give you 5* more ex. duration than the intake vs. what the 290 in. to ex. ratio is.

That would make for a good in between cam, see what Scott B. can do to make something like that for you to work with your compression.


Derek

 

I was fiddling around in the dyno simulator for a decent cam that would work. I'm going to post the specs for it now and see how close it comes to something else anyone can come up with.

It's not the most powerful cam, but would fit this combination and be relatively gentle on the valve train vs some of the other cams suggested/listed, and still give very good results.

LSA 114
Duration @.006: 286/300 with 65* overlap (good intake vacuum on a 455) and 14* exhaust emphasis
Duration @.050: 224/242 with 5* overlap and 18* exhaust emphasis
Lobe lift: .305/.302 I/E
Valve lift @1.55: .473/.468 I/E (this gives a 2.38 ramp intensity, which is relatively mild and safe for a flat tappet cam)

End result is 62*/58* I/E intensity with exhaust emphasis on duration, and intake emphasis on lift, with each lobe having exactly 2.38 ramp profile for added durability and longevity.

It would have a nice little lope at idle, along with excellent intake vacuum for power brakes.

Compare the overlap values to the TA 284-88H cam, which shows 66* overlap @.006 and 6.5* overlap @.050.

Idle characteristics compared to this cam would show the custom one I just posted to have a slightly smoother idle with slightly more intake vacuum, but with considerably more emphasis on the split duration values for use with exhaust manifolds.

Any comments/suggestions/critique on this would be appreciated.

 

The mini KB118 for milder 455s!

This is interesting and wish I was an expert. Your emphasis on exhaust seems to favor stock manifolds. I wonder if most of the cams on the sheet are really made with headers in mind?

 

I put in the KB118 specs into the simulator, and the custom cam I just posted makes a little more power.

I originally tried to tweak the KB118 a bit, keeping the exhaust emphasis it has at .006 (20*), but this seemed to hurt power a bit vs rearranging the .006 values, raising the intake side and lowering the exhaust side so that it came up to 14* instead, keeping the 65* overlap with the 114 LSA I wanted to use. This change alone showed several ponies and ft. lbs. better.

Then I backed the .050 values down some to help with lower end, as well as tightened the LSA up from 118 to 114.

I made the exhaust lift to 2.38 ramp intensity (which came out to .468@1.55), then matched the intake to this same 2.38 ramp intensity (coming out to .473@1.55), which added a little bit of lift emphasis on the intake. This design will help the exhaust's extra duration draw on the intake's lift a little better and helps with power in a somewhat restrictive environment. It also widens up the powerband.

Any restrictions to the exhaust will require more exhaust emphasis. The stock cam shows 31* @.006 emphasis, for reference.

You don't want too much though. Tighter timing events will result in more power, but usually observed with freer flowing exhaust systems. Too tight on manifolds and you'll have residual exhaust left in the combustion chamber that couldn't escape (which would have been drawn out if headers were used because the scavenging would have pulled it out), which can reduce power over a cam that has more exhaust duration, so it has time to evacuate when the exhaust is restrictive. As mentioned before, this also has the added effect of drawing harder on the intake at higher RPMs with exhaust gas momentum, which will raise the powerband and peaks (despite the intake's duration being smaller), and is particularly effective when you increase the intake's lift over the exhaust.

Powerband on the custom cam I posted is similar (though a bit higher) to the TA 284-88H, with a bit wider curve (peaks showed 3200 RPM for torque (with the cam showing good torque @2000-2500 RPM) and 5100 RPM for horsepower using cleaned up stock heads and stock valves).

With your compression ratio, detonation should be a thing of the past with this cam, and with the use of Jim Weise's converter, would be a pretty fun combination.

I wouldn't shift it much past 5500. I'd use TA's 1107 dual springs (100 lbs. closed, 250 lbs. open; vs the 80/220 for new stock springs) and stock rockers.

Get an "X" pipe for your existing dual system too.

Upgrading your rear end gearing to somewhere between 3.42-3.08 and you'll be set (did you already mention your gearing? I can't remember, sorry).

 

Thanks Gary! I have 3.31 gears now and very happy with those.

Typically how much more Hp and torque do you see with the custom LSA114 vs. the TA 290-94h? And what hp/torque total vs. rpm were you seeing? Thanks.

I need to think torque converters too. Cost is a concern.

I'm at:
3200 rpm at 70 mph
3000 rpm at 65 mph
2800 rpm at 55

Seems like it would match good with Jims 2800 flash stall.

 

That depends on what all is done to the engine.

The TA 290-94H cam will make a little more power vs the custom cam I posted if you have freer flowing heads and headers, but with near stock heads the custom one I posted makes a little more power vs the TA 290-94H (even with headers, according to the dyno simulator).

This goes back to what I was describing earlier about air flow and how the valve timing events behave depending on the environment they're in.

The IVC point @.006 is the exact same between these two cams, so DCR would be the same. The powerbands between these two are very similar as well, but the custom one I posted has a slightly wider one with slightly flatter curves, with a slightly higher peak value when used in a more restrictive environment. The inverse is true when using better heads for the TA cam.

In short, the custom cam is a better match for your combination than the off-shelf cam, but the rest of your engine could be built around that TA cam for better results, instead of the cam custom tailored to your existing combination.

One more thing to consider is that the intake lobe on the TA 290-94H cam has a ramp intensity of 2.35, while the exhaust lobe has a 2.45 intensity. This is a common theme on many performance cams I've observed, where the exhaust is made to be more intense with stricter timing events which work great within a freer flowing environment. This will also create a harder draw on the intake in a more precise way, which is another reason it works well in a freer flowing environment.

It's another angle of attack towards a solution, as is the cam design I showed (I didn't invent the design philosophy (at least I don't think I did, though I've added some 'tweaks'), as I have seen it elsewhere), but for different environments.

The lobe intensities on the custom cam I presented are milder by comparison too.

Of course, this IS a computer simulator, which doesn't take everything into account, so take that for what it is.

I was hoping others would chime in and give their insight, as this is not my profession and I do this mainly for fun. If it can help some people along the way, then all the better.

I do not want to steer anyone in the wrong direction, so please get professional advice and just take my advice as another point of view from your resident eccentric thinker.

Having said that, I do have engine building experience and skills (particularly Buicks, which I'm an old die-hard fan) and considerable knowledge in this field, so my thoughts and suggestions are not just pulled out of thin air.

Take it all into consideration and take your time making your decisions.

Peace

 

Glad to see you seem to have settled on a cam swap. I'm in the high 12's with the TA 290-94 in a totally unported, all iron motor. I do agree with a custom cam, if you have the time. I wanted to go off-the-shelf thinking my motor project would be quick. (A corollary to the "Take your budget, and then double it" rule should be "Take your expected timeframe and quadruple it..." LOL)

 

Quadruple..... that would be very efficient for me! I'd like to try a cam swap myself, preferably with someone who would be willing to help. I'd even pay someone. The thought of just dropping it off somewhere doesn't fit my pride and ego for well.....

I may just do mandrel 2.5" exhaust with xpipe this summer as that would be done no matter what I do later.

 

I ordered the 2.5" mandrel bent exhaust with a cross pipe from TA this morning. Hope to have it on in the next two weeks. I don't see going over 500 hp anyways. This way I can him and haw more about the cam and torque converter, while still accomplishing something this spring.....

thinking ported exhaust manifolds too now.

 

Jim, what's the stall range on your 9.5" converters and torque ratio? And ignorant question here, what's VP? I'm assuming variable pitch.
Thanks,
Matt

 

Stalls speed depends on engine ouput vs vehicle weight, and is influenced by everything from engine state of tune, to rear gear ratio and tire height. Generally speaking, the tightest combo we build will stall between 2800 and 3200 in your car. Stall Torque Ratio is 2.1-1. I have had that combo in 450 HP Stage 1 motors, all iron and totally stock appearing.. a convert with 3.42 gears..frame off resto. Was actually too tight for the customer's preference, so we switched him to the next combo up, and he loves it.

JW

 

The 9.5" torque converter is installed. I shaved 0.25 seconds off the quarter mile. Different days and conditions figured in. I'm sure to say 0.3 seconds is reasonable.

2.5" exhaust will be on this weekend.

I also have the TA 288-94H cam in possession but not installed.