Cam Opinion

[CV355]

I got the cam specs for the engine build in progress.  Only the 7th Bullet cam I've purchased

(Bullet Cam Card)
287/299-10HR
Duration @ 0.050 = Int. 233 / Ex. 245
Lift Int. .595 Ex .595

This is on a 9.6:1 build, 464, TrickFlow heads.  I don't have much experience with FE cams, but comparing it to what I've read on others, this doesn't look too aggressive for the street- seems moderate.  Has anyone run anything similar to this?  I'm curious if I'll need a vacuum pump for the brakes.

I'm not going for super high performance, just want it to sound good and run decently on the street.  The previous setup was dicey, and I have no idea what the cam figures were as there was no documentation on it and I didn't want to measure valve events.

[My427stang]

The -10 should mean on 110.

Should be a real nice combo, in fact, I am using Comp lobes, but it's very similar to one I am going to run 1st week of August in a TF 461. although I spread the centers for power brakes.  Likely could have lived with more compression, but it will be easy on fuel.  I'd guess it'd like about 30-32 degrees total because of the lower compression.

I do expect you will need a vacuum pump at 73 degrees overlap.

Should make big numbers whether you are going for performance or not

[CV355]

The -10 should mean on 110.

Should be a real nice combo, in fact, I am using Comp lobes, but it's very similar to one I am going to run 1st week of August in a TF 461. although I spread the centers for power brakes.  Likely could have lived with more compression, but it will be easy on fuel.  I'd guess it'd like about 30-32 degrees total because of the lower compression.

I do expect you will need a vacuum pump at 73 degrees overlap.

Should make big numbers whether you are going for performance or not

Sounds good to me!  The end goal is to put about 6psi max through it, so we left the compression ratio a bit lower for now.  Nothing crazy.  I'm assuming it'll be fun and choppy at idle with that much overlap.   

[blykins]

Did you tell them it was boosted?

[CV355]

Did you tell them it was boosted?

They know it is going to be N/A to start.  We might throw 6psi at it in a year or two.  Seems like a lot of overlap, might bleed a lot.

[blykins]

Yeah, it will bleed a lot.   I can't figure out why they took some pains to pick more aggressive lobes (as you would to try and curb overlap) and then split the intake/exhaust that far (which is what you want for a centrifugal supercharger), but then they go and put it on a 110.   That cam would have been absolutely perfect on a 114-115 LSA, with some some lobes that would have been a little less noisy. 

[My427stang]

Yeah, it will bleed a lot.   I can't figure out why they took some pains to pick more aggressive lobes (as you would to try and curb overlap) and then split the intake/exhaust that far (which is what you want for a centrifugal supercharger), but then they go and put it on a 110.   That cam would have been absolutely perfect on a 114-115 LSA, with some some lobes that would have been a little less noisy.

Agree completely, I didn't know it was boosted either, seems like a nice N/A cam, but leaving a little on the table for both brakes and boost

[CV355]

Yeah, it will bleed a lot.   I can't figure out why they took some pains to pick more aggressive lobes (as you would to try and curb overlap) and then split the intake/exhaust that far (which is what you want for a centrifugal supercharger), but then they go and put it on a 110.   That cam would have been absolutely perfect on a 114-115 LSA, with some some lobes that would have been a little less noisy.

I wish I had more insight, but I have an ankle-deep understanding of cam geometry and design.  The only thing I can think of is that I told them this was street-only, so they took that as keeping the peak torque lower in the rpm range with the 110?  I'm sorry if this comes across as a juvenile question, but could that combo be aimed at a "showy" idle without hurting street manners? 

Yeah, it will bleed a lot.   I can't figure out why they took some pains to pick more aggressive lobes (as you would to try and curb overlap) and then split the intake/exhaust that far (which is what you want for a centrifugal supercharger), but then they go and put it on a 110.   That cam would have been absolutely perfect on a 114-115 LSA, with some some lobes that would have been a little less noisy.

Agree completely, I didn't know it was boosted either, seems like a nice N/A cam, but leaving a little on the table for both brakes and boost

It's not boosted yet, it'll live in the N/A world for a bit.  I did not anticipate as drastic of a restoration as we needed to conduct this year when we pulled the engine.  We chewed through half our budget before even getting to the engine, but that's how it goes sometimes.

[blykins]

Yes sir, 73° of overlap will thump.

[Joe-JDC]

It has been my experience that anything that will work NA, will only work better boosted.  If it idles NA, it will idle with blower.  Yes, EFI works better with more overlap, like 114-117*, but not a deal breaker if you do have 110*.  Also, a mild camshaft that idles like a grocery getter will work just great with boost.  We have gone 10.75 @ 141 with a dead stock 302 HO shortblock and ported iron E7 heads and ported stock intake and plenum.  Joe-JDC

[My427stang]

Here is one with 25 more cubes, 71 degrees overlap, and EFI. 

Yours will likely be just a smidge more rowdy, but not crazy.  Don't worry, it'll run REAL strong, just not optimum for boost.  In fact, some would say (including me) mine is a little too much overlap, but with some tuning in the EFI they can do real well

https://youtu.be/AtTEvZ2uQmA

and just for fun, when the same motor had a 1000 Holley and an RPM intake

https://youtu.be/QcUCi_AxjqQ

[turbohunter]

Mm mmm good

Hah
The female reaction is priceless in the second

[CV355]

Here is one with 25 more cubes, 71 degrees overlap, and EFI. 

Yours will likely be just a smidge more rowdy, but not crazy.  Don't worry, it'll run REAL strong, just not optimum for boost.  In fact, some would say (including me) mine is a little too much overlap, but with some tuning in the EFI they can do real well

https://youtu.be/AtTEvZ2uQmA

and just for fun, when the same motor had a 1000 Holley and an RPM intake

https://youtu.be/QcUCi_AxjqQ

I don't know what it is about a thumpy idle, but it's a guilty pleasure for sure...  My GT500 had some rowdy cams, it'll be nice to hear something thumpy again.

Mm mmm good

Hah
The female reaction is priceless in the second

My wife knew I used to be big into drag racing before I met her, but I didn't have a fast car again until we got the GT500.  After we hit around 800hp, I took her out in a ride in it and said "hey, have you ever heard a car bark?"  She goes "no."  I barely tapped the throttle in 3rd gear and she totally freaked.  Now she's into it big time.  Even her 5.0 has an obnoxious exhaust now and she has talked about wanting a supercharger on it.  Sometimes during the winter I can hear her leave work, which is 2.5 miles away.  I'll brag on her a bit

[blykins]

Generally speaking, you want less overlap so that the effort from the supercharger doesn't go right out the exhaust.   

It just may surprise you and it won't need a blower.....you're a hair low on compression and duration, but you should still be in the 530-540 hp range I'd think. 

[wayne]

Joe 10.75@141 with a stock 302 short block the little guys can be nasty good job like to hear about any ford that runs.

[mike7570]

We have gone 10.75 @ 141 with a dead stock 302 HO shortblock and ported iron E7 heads and ported stock intake and plenum.  Joe-JDC

141 is what my SG car ran at 9.50's et, no traction with that 302?

[Joe-JDC]

Traction was an issue, showroom clean street car with all the options.  LX coupe, 5 speed with 8 psi.  Just saying that a camshaft is not necessary for a stockish engine to perform well with boost.  Did break the axles, had to upgrade to 31 spline Mosers, and traction lock.  Joe-JDC

[My427stang]

N/M

[cammerfe]

Some years ago, I had Comp spec a cam for a 397 I was building. I asked for the street manners of a 'AA' '64 427 engine with all the later technology they could put in it.

They sent me a 242-248 on 110, with .652-.666 lift. When we finished the break-in, of about 20 minutes at about 3000, and running it up and down during that time, it idled at about 850 with a wonderful bit of lope. I loved it!

KS

[blykins]

You know, the fact of the matter is that a lot of cams will work.  For any given build, I could probably use a Comp 270H, 282S, etc., etc., and the engine would make power and the customer would be very happy.  However, it's not until you start comparing camshafts that you find that there are better ways of doing things, making improvements, etc. 

For instance, I built a 445 with Trick Flow heads, Performer RPM, 10.3:1 compression, QFT 780VS carb, roller rockers, Canton pan, etc., etc., and made 547 hp @ 5500 and 588 lb-ft of torque. 

I also built a 445 with Trick Flow heads, Performer RPM, 10.3:1 compression, QFT 780VS carb, roller rockers, etc., etc., and made 536 hp @ 5500 and 575 lb-ft of torque. 

Do you know what the difference was?  If you didn't notice the "guess the horsepower game" thread that was centered around this, I was testing two camshafts.  One was 231/239 @ .050", .630" lift, 114 LSA on a 105.  The other cam was a 231/235 @ .050", .630" lift, 113 LSA on a 105. 

Those are seemingly miniscule changes that the average guy would think nothing about.  And even though I purposefully kept the overlap exactly the same to eliminate that as a variable, there was 11 hp difference and 13 lb-ft of torque difference on the peaks.  You may think that 11 hp and 13 lb-ft isn't that much, but if you paid for a new cam, would you rather have more hp or less?

It's not until you try back to back camshafts that you really learn what some engines/combinations like.  Until then, you could be leaving some power on the table.  Unfortunately, I don't think a lot of cam companies get back to back testing feedback, especially on engines that are not mainstream, like the FE, Cleveland, etc.  IMO, that's why I think engine builders sometimes have a better handle on what an engine combination wants than a cam grinder.

This reply wasn't in response to anyone in particular, just random thoughts at 6:20 in the morning, waiting for the caffeine to start working. 

[1968galaxie]

Are you going to replace the camshaft used in the second 445 Trick Flow engine build? (i assume both customers paid for custom cams)
The first design you used made 11 hp and 13 ft lbs more than the second cam design.

When testing ANY two camshafts in a build comparison clearly there will be one better and one less optimum for the combination.

An interesting comparison would have been a similar duration/rpm range standard hydro roller "catalog cam".

Nice builds nonetheless!

[cjshaker]

If you build 2 identical engines, I wonder what the variance would be in hp and tq output, on an average? I know theoretically they should be the same, but I'd be surprised if they were identical.

[blykins]

Are you going to replace the camshaft used in the second 445 Trick Flow engine build? (i assume both customers paid for custom cams)
The first design you used made 11 hp and 13 ft lbs more than the second cam design.

When testing ANY two camshafts in a build comparison clearly there will be one better and one less optimum for the combination.

An interesting comparison would have been a similar duration/rpm range standard hydro roller "catalog cam".

Nice builds nonetheless!

Yes, and knowing how to choose the better cam is where the experience comes in. 

I'm not going to replace it.  He was wanting 475 hp and he got more than he wanted. 

I haven't tested against "shelf cams" because I don't want to pay for them and end up with something I can't use.   But I have tested against other custom cam grinders' cams.  I was up 28 peak hp and 10 average horsepower in one engine against another guy's cam.  That was a cam swap in the same engine on the same day, actually within a couple hours of each other. 

[chilly460]

Agreed, it would be very interesting to run a custom vs a modern shelf cam.  There's so little difference in price, makes all the sense in the world to have a cam guy spec a grind who's familiar with your combo, engine idiosyncracies, and head/intake flow figures....but would still be interesting to see what it's worth.   Hell, I'd be happy to see a comparison of something like a shelf single pattern vs XE cams from Comp, as I still see a LOT of recommendations for something like a 270H or 282S.  That said, still not going to be an absolute as the comparison on any one combo is only so valuable for any other combo with it's own variables. 

[CV355]

You know, the fact of the matter is that a lot of cams will work.  For any given build, I could probably use a Comp 270H, 282S, etc., etc., and the engine would make power and the customer would be very happy.  However, it's not until you start comparing camshafts that you find that there are better ways of doing things, making improvements, etc. 

For instance, I built a 445 with Trick Flow heads, Performer RPM, 10.3:1 compression, QFT 780VS carb, roller rockers, Canton pan, etc., etc., and made 547 hp @ 5500 and 588 lb-ft of torque. 

I also built a 445 with Trick Flow heads, Performer RPM, 10.3:1 compression, QFT 780VS carb, roller rockers, etc., etc., and made 536 hp @ 5500 and 575 lb-ft of torque. 

Do you know what the difference was?  If you didn't notice the "guess the horsepower game" thread that was centered around this, I was testing two camshafts.  One was 231/239 @ .050", .630" lift, 114 LSA on a 105.  The other cam was a 231/235 @ .050", .630" lift, 113 LSA on a 105. 

Those are seemingly miniscule changes that the average guy would think nothing about.  And even though I purposefully kept the overlap exactly the same to eliminate that as a variable, there was 11 hp difference and 13 lb-ft of torque difference on the peaks.  You may think that 11 hp and 13 lb-ft isn't that much, but if you paid for a new cam, would you rather have more hp or less?

It's not until you try back to back camshafts that you really learn what some engines/combinations like.  Until then, you could be leaving some power on the table.  Unfortunately, I don't think a lot of cam companies get back to back testing feedback, especially on engines that are not mainstream, like the FE, Cleveland, etc.  IMO, that's why I think engine builders sometimes have a better handle on what an engine combination wants than a cam grinder.

This reply wasn't in response to anyone in particular, just random thoughts at 6:20 in the morning, waiting for the caffeine to start working.

Interesting info, I hadn't thought of that, to be honest. I guess part of it comes down to factors that are hard to quantify or control becoming a deterrent in finite testing.  Back when I had my drag car, one particular day we did 3 back to back dyno tests, let it cool completely, and then 3 more.  The HP/TQ figures were all over the place- probably around 40hp-50hp range with no real changes to tuning.  Granted, it was a bizarre turbo setup that I doubt had been done before on that particular family of engine, and it was a chassis dyno, not an engine dyno. 

If you're doing back to back tests and are able to differentiate ~1-2% differences, that's impressive.  A lot of people will think "eh, the dyno is a tool, it's close enough."  If you're actually doing testing to that level, that is cool.

If you build 2 identical engines, I wonder what the variance would be in hp and tq output, on an average? I know theoretically they should be the same, but I'd be surprised if they were identical.

I suppose that comes down to the precision of the components going into the engine and how they are both broken in.  We hear of "factory freaks" now and then, but that's mainly just a statistical anomaly that worked in the buyer's favor. 

I'm curious what Brent has to say on that topic.

[blykins]

An engine dyno will repeat within 1-2 hp on back to back to back tests, as long as the water and oil temperatures are kept the same.   They are accurate enough that if you're watching during the first 3-4 pulls on a fresh engine, you will see it gain on every pull and then level out.  Once it levels out, it's extremely repeatable.   

Chassis dynos on high horsepower vehicles not only have to worry about the temperatures of the transmission, rearend, converter loss, etc., but also traction loss on the rollers.  On a big power engine, it would be simple to "lose" 40-50 hp somewhere.

The variance between two similar engines should also be very close.  The factory freaks that you're referring to is just basic manufacturing tolerances that aren't checked and corrected at assembly.  If a particular engine gets a piston that goes to zero deck height, the cam timing is dead on where it should be, then the next engine has the pistons .005" in the hole and the cam is retarded/advanced past optimal, then you can see some good variation. 

The cam test from above was a continued "back-up test" to what I've been doing for years, but to also see how much duration played a role versus overlap.   I always split the duration based on the intake/exhaust flow of the cylinder head, but it's nice to verify your practices every once and again, especially with new combinations.  I'm one of the guys who likes to try different things, so I can have more data to pull from.  If I send out 10 cams and no one reports back, or no one compares it to another cam from another grinder, I have no real comparative data.