[pastry_chef]

Originally Posted by Chris-Austria

bigger and most people I ask think that my actual cam is rather small, so it cannot hurt and will surely give more power.

Yes, better filling needs (image in post 17).
Many put way too much value into .050 . it is only one point.
They covet the same .050 cam duration regardless of rocker ratio but the valve motion result is way different.

[Cliff R]

"Cliff... if you search the same thing you will get 100 different results since every engine is different, thats also what I had and didn't like... I found many posts about what the OF is about and also different results, but an engine with the same cam I have now and nothing else changed but the OF cam is perfect (for me)"

The OF camshaft in a well thought out 455 engine build is going to net somewhere around 540-560hp and 580-610tq. The only one I had fall short was a build that I assembled for a customer but picked none of the parts. I had the small chamber KRE heads on it ported by Dave at SD and a HUGE dish in the pistons to get it down to around 10 to 1 compression. Not sure why but it just didn't work out well on the dyno and initial pulls were down around 490hp and not much over 500ft lbs torque. I didn't put a lot of effort on dyno day to chase the numbers to found out why because I was only hired to assemble it and the owner really didn't much care about all that anyhow.

We're not building one of these engines for HP right to start with, we are trying to make the most power (torque) over a broad RPM range. Don't look at peak numbers look at how much power is made in the 4000-5500rpm range. Even with the dyno runs below there is only 43 ft lbs torque difference in peak values, but gander down and look at how much more torque the bigger cam is making around 5000rpm's and up. With smaller cams on tight LSA's power peaks high and early in the RPM range then falls off very quickly past 4000rpm's or so. We like to see at least 500ft lbs around 4900-5100rpm's not clear down at 420-440ft lbs. This is what makes the vehicle fast on the street and at the track and it will be pulling really hard and run good track numbers no matter where you shift it........

[Chris-Austria]

Would be really great if I can get it to over 500hp, but it's not the goal to get as much hp as possible. It's like you said... I feel my combination likes some rpm and I want to bring the power band into the region where it matters.
I also thought it would reduce some power down low, which might help with the launches. At the moment the car is hard to control with street tires... it wants to go sideways and will not grip.

I used a gps tool to measure 0-60mph times and the GTO couldn't get under 5.3 seconds... my V6 Challenger will do 6.0 seconds... so the result is horrible
From the track days I know the GTO can do around 4 seconds and that is still with traction problems.

[Chris-Austria]

Originally Posted by TCSGTO

The Sportman ST wouldn’t be much different than the TA radials for bite. The SS radials would be a big step in the right direction. I hear their not too bad in the rain either. They have a decent amount of tread so unless you’re inspections are super strict you should be ok.
Must be pretty cool tooling around the Austrian countryside in old American iron.

Our inspections are pretty strict... would need some luck that it will pass. I also prefer the white letter for the look... would be nice to find some white letter tires with grip.

And yes, I love cruising the countryside and the mountains with the GTO. I live at about 1500 feet and drive it up to maybe 5000 feet. Not too many other American iron around in my region, but there is a small community. I should drive it more often, but it's probably only 1000 miles a year...

[Cliff R]

Chris, the other problem with using a relatively small cam on a tight LSA in a 455 build is EXACTLY what you are seeing for traction problems.

The small cams are excellent for cylinder filling abilities down low and throw ALL the power at you right off idle and quickly. This makes the car "feel" strong and instantly roasts the tires with any quick hits of the throttle.

Going to a larger cam/wider LSA will tame this a bit and produce a more "locomotive" power curve. It will still be difficult to hold on the street but the broad/smooth/flat power curve will certainly benefit vehicle performance at all levels compared to an engine that just dumps all of it's power at you quickly.

It took some suspension work but I am able to hook my OF cammed 455 on a 255/60-15 Mickey Thompson Drag Radial. My engine also has 11.3 to 1 compression and ported KRE heads from Dave at SD. Sadly they closed our local 1/8th mile track this year, but I've wondered over there many times on Friday nights to their Test and Tune session. Doing nothing more than dropping the air pressure in the tires from 24 to 18psi I've clicked off low 7 second runs in the 95-97mp range without even shutting off the engine or cooling things down. Even so the DOT's don't hook well on the street if you go stick it really hard so some driver control is needed to get a good launch in a street race.........Cliff

[Chris-Austria]

Best time I got was a 8.5 on the 1/8 mile.. 60ft was only 2.16 and speed was 87mph if I remember it right... that was with traction problems and started with only idle rpm... I must admit that I've also got not too much track experience.. so probably another driver could get the GTO down to very low 8's I guess

At this point I'm sure to get a 236/242 (or little more) cam, but I need to decide the LSA, keeping in mind that it is still mostly street driven and that I have to pass smog tests. I also don't want it to have a bad idle, so I'm tending to the 114 LSA version.

[Cliff R]

Wide LSA reduces overlap and improves idle characteristics all else being equal.

The car will also run quicker at the track with more upper mid-range and top end charge from the larger cam, traction or not. The smaller cam hurts you both ways in a drag race. Spins the tires then once it finally hooks up your well past peak torque so not pulling hard in the upper RPM's. Here's a clip of my car at the track short shifting at 5000rpm's. The engine will pull hard to at least 6000rpm's but it really doesn't pick up all that much so no need to "grind" up the engine just to put up a little better time slip.......

https://www.youtube.com/watch?v=6zVdoLR-VzM

[Dragncar]

My 455 slows down if I let it go to 6K. 5500 and get it into high gear as fast as possible is where it runs quickest.

[Cliff R]

I see about .05-.08 seconds improvement and nearly 2 MPH if I shift clear up at 5800rpm vs 5000. Since I use Crower HIPPO lifters on the OF cam it spins right past 6000rpm's quickly with no indications of giving up but I don't think the cam is big enough to be making power up that high. Certainly not enough improvement to push the engine that hard, and 455's are pretty hard on internals by design so lower shift points only make sense for bracket racing and such......

[Steve C.]

Cliff regarding the comparison between the Comp XR276HR cam and the Old Faithful cam with no other changes. Within your post #20 here you mention the XE cam pinged so hard it required rod bearing replacement before the dyno testing could continue.

Food for thought, prior to testing the OF cam can we presume they rebuilt the motor with new bearings and if necessary likely could have had the crank turned? In a roundabout way that in itself is a change. Could the damaged bearings affect the first dyno session with the XE cam ?

Example, during a chassis dyno session on a very mild 455 motor the Q-jet carburetor was replaced with a throttle body EFI system. They made a few dyno pulls with the EFI in place but something was wrong, it was found there was a bad injector in the throttle body. It was leaking by continually spraying. Not realizing that the engine was damaged at first, the throttle body was replaced. With no other changes they put the car on the dyno and made several pulls. Even on this mild of a motor, I was still down over 20+ rwhp, and that is when they realized the engine might be hurt. Without realizing it, the bad leak had washed down some cylinders, contaminating the oil. On tear-down, some rod bearings had gone bad. On this motor that may have been 350'ish flywheel HP, it was down 20+ rwhp with bad rod bearings - which would be maybe 30 HP at the flywheel.

Now on a motor making much higher horsepower the loss could be 50+ HP at the flywheel, maybe even more since it is operating at a higher RPM than the smaller motor, and such damage would cause more issues as the RPM increases.
Does that make sense?


.

[Cliff R]

"Food for thought, prior to testing the OF cam can we presume they rebuilt the motor with new bearings and if necessary likely could have had the crank turned? In a roundabout way that in itself is a change. Could the damaged bearings affect the first dyno session with the XE cam ?"

Good question Steve and I'll explain EXACTLY what happened to clear things up and explain the power differences at the same time.

My phone rings while they are on the dyno.

I had NOTHING to do with the build other than supply a custom rebuild kit and tuning parts for the carburetor. The shop owner was also the engine builder and dyno operator and well versed with carburetors so he opted to do his own which was fine with me.

Dyno day came and they started making pulls on the engine after "run-in". They started with conservative total timing (good idea with this sort of thing). First pulls were WAY off where they thought it should have been so they started advancing the timing. Power did not improve and they had audible detonation instead so stopped the testing and called me. As usually EVERYONE associated with the build was blaming the Q-jet. I asked him about the engine details and he responded that they bought a complete stroker "kit" to turn the 400 into a 455 and it was topped with professionally ported #96 "D" port heads that flowed 250cfm, 9.3 to 1 compression and Comp recommended and sent them the XR276HR camshaft, it was installed per the cam card to 106ICL.

I told him that I had ran into the SAME issues with that cam several times with relatively "low" compression 455 engines topped with good flowing iron heads and my advice was to REPLACE THE CAMSHAFT.

Instead he opted to bolt on their "dyno mule" Holley carb and to continue making pulls on it. So he advanced the timing, installed the big Holley carb and pinged the engine so hard on the dyno that it spun the rod bearings and had to be torn down to replace them.

After it blew up he called me for a cam recommendation and sent the Q-jet back here so I could check his work. I checked out the carb, it was fine and sent it back. I had him order a 289/308, 236/245 @ .050" HR cam on a 114 LSA with instructions to set it at 110ICL. The phone was silent for a few seconds but he did as I asked. A week or so later I got a call from him after the engines rod bearings and cam were replaced and he sent me copies of the new dyno sheets.

He also noted that the engine was fine now with more timing in it, and it actually idled better than the smaller cam with less initial timing. He also noted that they had no detonation issues anyplace and very happy with the end results.

That's how it went, so if the rod bearings were holding it back nearly 90HP then we can blame them for the big power loss, because those were the only other items changed besides the camshaft from one dyno test session to the other.......Cliff

[Formula8]

Originally Posted by PunchT37

Tires will go a long way.


Intake, with FI ? Go with T2.


I might try those 2 changes 1`st.


That cam change will make the whole thing better after the 1`st 2 changes. Should be good to 5800-6000 after that.

This is exactly what I was thinking. Most TB FI's work best with a single plane intake AND it would kill off some of the low end pushing the RPM range upward which seems like exactly what you want to do. On a manual trans car.......even more so and about 1/8 of the hassle of a cam swap.

I would pull the RPM, put on a Torker II (which you can find used) and maybe mess with the timing curve a bit, sell the RPM on this forum and you will probably make a few bucks on the deal.

[pastry_chef]

Originally Posted by Steve C.

Food for thought, prior to testing the OF cam can we presume they rebuilt the motor with new bearings and if necessary likely could have had the crank turned? In a roundabout way that in itself is a change. Could the damaged bearings affect the first dyno session with the XE cam ?

You are thinking Steve.. we've seen that to be a bad thing for some here. Sorry state.. does note matter a damn who we like.

Science is science.. crap is crap.

If Mike Jones says about 40 HP between the cams. I bank that.
He is one of the best, IF not THE best camshaft man in the world.

You earn points with me on merit and nothing else. If someone ever tries to kiss my butt, you better be careful, it won't work. Too much dishonesty and bribery in this world.

[Steve C.]

Ok then we agree, if the rod bearings were holding it back nearly 90HP then we can blame them for the big power loss.

We will never know.

I can say I had a somewhat similar situation with a new engine build. On the dyno with a custom Crower solid roller cam it made 640 HP at 6000 rpm. Right after the engine went into service I started seeing oil pressure issues, enough so there was cause for concern. We tore the engine down and found a bearing issue. We turned the crankshaft and replaced the bearings. At the same time while the engine was apart I decided to ditch the Crower cam and replace it with a UltraDyne solid roller cam that had 5 degrees less .050" duration and less lobe lift. Back on the dyno with only these "two" changes the engine made 660 HP at the same 6000 rpm. I don't think the cam change was the only improvement in power. I suspect there was a bearing issue during the first dyno session we were not aware of.


.

[Stan Weiss]

4.12 Bore, 4.25 stroke. 9.3:1 CR A 276 intake degrees @ 106 ICL is 32 BTDC / 64 ABDC. 7.52:1 DCR and should have cranking compression of around 184 PSI. That should be able to run on 93 Octane with Iron heads.

Stan

[pastry_chef]

Originally Posted by Stan Weiss

4.12 Bore, 4.25 stroke. 9.3:1 CR A 276 intake degrees @ 106 ICL is 32 BTDC / 64 ABDC. 7.52:1 DCR and should have cranking compression of around 184 PSI. That should be able to run on 93 Octane with Iron heads.

Stan

Tom S did that, had that same cranking PSI and drove thousands of miles on 91 octane.

[Stan Weiss]

Cliff,
Let me get this straight. You did not spec or build this engine. You did not dyno the engine. You did not see the engine to know what might have been wrong with it after the first dyno session. You are basing all of this on second hand knowledge. I don't think anyone is questioning the numbers from the rebuilt engine with your cam selection. But I and many others did think there is something fishy about the original build / original cam dyno numbers.

Stan

[pastry_chef]

Originally Posted by Stan Weiss

But I and many others did think there is something fishy about the original build / original cam dyno numbers.

Stan

Well said.
Discussed in private with many as well.

[dragracerx2813]

I am just wondering how long you guys are going to keep debating a Dino sheet? Do you think if you keep debating it that your going to change someone’s mind. For the love of god let it go!

[Stan Weiss]

Originally Posted by dragracerx2813

I am just wondering how long you guys are going to keep debating a Dino sheet? Do you think if you keep debating it that your going to change someone’s mind. For the love of god let it go!

I know this is the internet and wrong / misleading is posted all over the place. But I any just trying to make sure that anyone reading this thread now or later on including the OP understand what is being perpetrated here.

Stan