aaronz28

I posted this in the other thread about 30-30 cam, but i suspect many weren't following the nature of that thread, so i am starting a fresh on.

I'v been raving about this 30-30 cam I got from predator camshafts this past summer and i've been called to task about getting some dyno results.

When I got this car, it has an OE 30-30 cam in it.. after trying two other aftermarket cams, i went to this Predator 30-30. I also replaced a GM LT1 cam that was in my 64 Vette when I got it with this same piece.

This dyno pull is of my Completely restored and dead mint 1969 Z28.
Stock DZ302... unported heads.. stock rotating assembly, compression was checked to be a true 11. to 1. Stock Z28 Intake,
Stock Point distributor, coil, wires, AC 44 plugs,
GM Z28 Headers from 1968... 1 3/4 primary with 3 inch collector.
2.5 inch exhaust with 1 crossflow muffler

Predator Cams states that this cam has the same durations at .050 and the same max lift of .485 on a 114 LSA. but with the faster flanks, the cam has less duration at the seat and more at and above .200 inch lift.

The carburetor is an 830 CFM double pumper. The stock 800cfm Vaccuum Sec Holley is out being refinished... you'll see that my torque dips a bit right at 2000 rpm roughly...you can feel a stumble in the pedal with this carb. I'm guessing that this is a missmatched powervalve situation, or an issue with the secondary pump cam, squirter, or linkage. If I would have had the Original carb on, which didn't have that stumble, i'd bet that it would have had an equally smooth torque curve and probably brought the 80% peak torque down a bit closer to 2000 rpm.

I did absolutely no tuning prior to the run. My valves have not been adjusted in about 5 months (since I put the cam in) i have no idea where the timing actually is as I set it at 36 when I put the cam in and thats the last time I checked my timing. So these are hardly ideal, and I'd bet that with a bit of time and tuning, my numbers would be even better..

so, I think for a stock 302, these are pretty damn good numbers.

The funny part, is that the guy whose car was on before mine was a 69 roadrunner with a 440 6 pack, and he was pissed becasue he only made 217 hp at the rear wheels. LOL.

These were done in 4th gear,

I'm going to try to get my 64 Coupe out which has the same exact cam but on a FI 327. It runs equally well through the manifolds and exhaust, but has 3.70s as opposed to the 4.10s in the Z, so the camaro feels faster.

Enjoy

Allcoupedup

Those do look like great numbers. Can I ask a favor of you though - can you not call it the 30-30 camshaft? The 30-30 had a specific design and once a parameter has changed, it is no longer a "30-30" camshaft. How is the idle with the predator cam?

Brian

AZDoug

Just as a point of reference, the original 30-30 cam has an almost identical cam profile/lift/ valvetiming/lobe center index to the L-46 hyd cam I run.

Without looking up the specifics, I recall that there are a couple thou diff in max lift and maybe 1-2 degrees difference in valve timing in one or two places.

I think the L-46 cam was designed to deliver essentially the same performance as the original 30-30, for those that didn't want to dork with solid lifters or run 7000 RPM all the time.

I think if your 302 had the 1/4" longer stroke to make it a 327, your dyno run and mine would heve been about identical on the lower end, though the 1/8" larger headers you have may still hurt below 2500 RPM.

Doug

ghoastrider1

so,should your shift point be around 5,200?

CoupeKeeper

what is the make-up of a 302? What block, heads, crank, etc?
Thanks for the info
Steve

Joel 67

The 302 was it's own motor for the 67-69 Camaro Z/28. Basically a 283 crank in a 327 block. In order to qualify for the Trans Am racing series an engine with less than 305 CID had to be offered in a production vehicle, hence the 302.

Joel 67

Sorry, 2.02 heads as well

aaronz28

Are you serious????

Hell no... when jumping on the car... i have shifted at about 7200, but knowing what I know now, I'll probably shift at 6700 (if I can help it)

if i'm routine street driving.... from stoplight to stop light,
i'll shift at about 4500.

The car is a treat to drive.

aaronz28

The 69 Z28 "DZ" block is nothing more than a 4 bold 350 block. the casting number is 010.

The crank is an 1178 forged large journal 3.00 stroke crank.
The 67-68 useda steel version of the 283 small journal crank.

Pistons are stock OE slugs, and the rods are stock "pink" large journal small block rods.

Heads are unported 186 heads... which are essentially 461s with accessory bolts... they are "camel back" heads.

Intake is a stock Z28 aluminum dual plane intake... it's predecesor was the 327 SHP intake manifold.. but the Z manifold is a better intake.

DZ fool

Bravo !!!!!!!!

Ironcross

Hi AA,

How long does it take you to get to 5K in the Z?

aaronz28

in 1st gear?

almost instantly...

Ironcross

Just like me! Immediately if you want. There was a discussion about lower rpm`s and I never gave them much thought as the Duece and Camaros were smooth from the bottom to the top. I suppose some bad combinations would have trouble down low in using the higher gears. Thanks AA,

L79vette66

Hey AARONZ28, What is the idle like? Does it lobe (hit) as HARD as the original 30-30 cam?

aaronz28

The idle is wicked... exactly as it was with the OE 30-30 camshaft.

as far as how the rpms climb...

i have 4.10s and a wide ratio muncie in my car...

that combination makes for a great 1st 2nd and 3rd gear... when shifting from 3rd to 4th, the rpms drop a bit... but I took it to 7200rpm in 3rd gear the other night getting on the e-way, and when i grabbed 4th, it droped right into the powerband at 5500 rpm.

if one does the math,, you'll find that the rpm drop between 1st 2nd and 3rd is identical between the close ratio and the wide ratio muncie... except the gearing on the wide ratio is lower so if you have 4.10s in your car,, it will feel more like 4.56s rpming.

i made this swap in my corvette and will never look back. even with 3.70s...

alot of guys maintain that the closeratio keeps the rpm tighter.... that is only accurate in 3rd to 4th... but again, with the wide powerband and torque curve of my 302, i take advantage of the wide ratio gearing, and as I said... when shiftin from 3rd to 4th the motor doesn't drop out of the powerband.

the only downside to the wideratio trans is "strength" because the helix angle on the gears is much bigger making it easier to rip teeth off...

However, I just built an M-22 rockcrusher using new US made gears that have the tight helix angle of the M-22, but the numerical gearing of the wide ratio transmission..... so I get the strength of the m-22, the gear whine that is associated with that transmission, but the superior gearing of the M-20. So it works perfectly.

I will never understand why GM didn't offer the wideratio gearing on a SHP corvette... it makes a huge difference in the vehicle's performance. Perhaps they were concerned about strength also...

I can honestly say that I beat the **** out of these transmissions, and I've never broken an M-20.... but i'm brutalizing them with small blocks...
i don't know if they'd handle the brute strength of an L88. LOL

aaronz28

I have to say that i'm highly suprised that the people who said I was nutz about this 30-30 cam haven't chimed in on this thread.

Not that i'm looking for a battle, but I made some serious claims, and was called to the mat on it, so I went out and had my car dynoed.

Although its hard to compare to the posted dyno numbers on motors with the LT1 camshaft because these other motors have ported heads and more cubic inches, but i'm curious to hear some comparisons.

Afterall, that is why I got the dyno tested anyway.

Additionally, I rebuilt and installed the OE 800 vac secondary carb and reset the timing this weekend and that stumble at 2000 rpm is gone... I also noticed that the car is smoother from top to bottom but doesn't seem to come on quite as hard at 4000 rpm.... perhaps that is perception becasue the motor is no longer recovering from a drop in power due to a powervalve or linkage issue? I'm not sure.... but I can say that the car runs like a charm, and I'd bet that if I had it dynoed again, it would be dangerously close to that 80% torque at 2000 rpm.

Which is a miracle in and of it self with 302 cubic inches and that big Unstreetable camshaft LOL.
Aaron

aaronz28

I've consistantly referred to it as the "Predator 30-30" which is what i've been discussing this entire time. Agreed that some parimeters have been changed, but had you just looked at the cam card... you'd never know it..

when I asked predator for the specs... they said...254 at 050, 485 lift on a 114... which is exactly the published specs for the OE. 30-30

They did not give valve opening numbers at 020, 050 etc...but I just asked one day becasue I was surprised at how much better it ran than the OE 30-30 that I pulled out of the car.

Thanks

Aaron

63 340HP

Aaron,

What I found searching and comparing the cam specifications is only a small difference in the Predator cam from the factory cam: the lobe Point of Maximum Lift (POML) centerline angle. The Predator grind is advanced two degrees, with the potential for less overlap if the lobe ramps are different (a big "if").

PREDATOR CAMS
ENGINE 265- 400 CHEVY
CAM GRIND # SBC30/30 DUNTOV (compared to Factory/Crane/BR/W WG1053, 346M, for the DZ Z28 302)

INTAKE / EXHAUST

DURATION @.050: 254 (254) / 254 (254)

LOBE LIFT: .323 (.3235) / .323 (.3235)

LOBE SEPARATION (POML): 110 (112 ATDC)/ 118 (116 BTDC)

SEAT DURATION AT (ADV): 314 (314) / 314 (314)

GROSS VALVE LIFT: .485 (.485) / .485 (.485)

VALVE LASH ( HOT): .030 (.030) / .030 (.030)

The only advertised dfference is the Lobe Separation timing (advanced two degrees).

I remember you mentioned that Predator would gind the cam on different lobe centers, and the cam matching these specs may be different from what you have, but the advertised POML lobe center difference is an identical 228 degrees, just advanced two degrees more than the factory cam.

What we cannot read is if the lobe profiles are similar and if the overlap is more or less? Knowing Predator reports they use a "modern" lobe profile the actual overlap could be anything (but the lobe center specs imply similar overlap).

A design that would parallel SWCDukes advice to minimize overlap (if we design to gain torque bandwidth) would be an advantage, but there is no confirmation that the Predator does this (although advancing a cam will rock the torque bandwidth down the rpm range).

It would be very instructive to read a chart of valve lift per crank rotation angle for the Predator cam (even if it only focused on the E/I overlap portion of the valve opening profile curves).

Whatever the design, your 302's Predator 30-30 cam 80% torque bandwidth range is slightly narrower that the LT1 and at a higher rpm range (what is to be expected with the different intake lobe & displacement). We can also read that the cam makes great power in the upper rpm range for an engine with unported heads.

The unknown difference we have to qualify in the power delivery of your 302, compared to most of the dyno testing posted here, is the limited break-in operating hours for the fairly recently assembled LT1's posted in the past. We should expect your 302 to be exercised more and have well seated rings with the corresponding good compression. The fresh L76/LT1 assemblies may not have the full benefit of sufficient break-in wear.

Your 302 should perform better with the tuning you completed (the SOTP feel you report), and the L76/LT1's should also perform better due to beneficial break-in wear (if they have been exercised). A more recent dyno test of a L76/LT1 with some high load run hours would probably improve on the posted reports, but the debate on what works best will remain (different compression, displacement, break-in care, intake, etc.).

Your dyno test results help those of us that have always savored the sound of a 30-30 cam at 6500 rpm and idle, but are concerned that the cam loses too much torque below 3000 rpm (your dyno runs counter the reports that the cam is worthless below 4500 rpm).

I can read you are happy with this cam in your 302 (and the chassis dyno reports support and quantify your SOTP dyno), and overall that is all that really matters.

aaronz28

Thanks and some great insight...

one thing that is clearly obvious... the 30-30 is well drivable under 4500 rpm... and 3000 is about where it kicks in.

in comparing to Ghostriders motor... which i don't think is fresh... mind you , I only have about 3000 miles on my motor.... i'm told that stock style rings seat rather quickly anyway...

by 3000 rpm, I'm making more torque, and it continues to climb an additional 20 or more ft/lbs above that of a motor with less overlap, a wider LSA, and more cubic inches... which in theory shouldn't be able to happen...

on the second run, the untuned motor is making 219 lb/ft at 1800 rpm, and then stumbles at 2000 rpm, i loose 13 ft/lb over 500 rpm, before it comes back strong.... it is safe to assume that if the stumble is worked out, not only would these numbers be smoother, but they would likely be slightly higher... bringing that 80% torque of (228) down below 2500, which is damn impressive for a 302 cubic inch motor.

if you look at Ghostriders dynos.... he doesn't make 228ft/lbd until 2400rpm anyway... with 25 more cubes... again defying the theorys presented here.

This is why, I don't believe that the 80% torque number is something to really compare engines with... aside from determining whether a single engine has a broad torque curve.

essentially, my engine doesn't make 80% until a higher rpm, but it makes more peak torque, so naturally the 80% number would have to be higher.... the engine isn't as broad, but makes more power in the usable power range.

Finally, the one thing that we've seemed not to discuss here is the effect that gearing and weight have on the accelleration of the car.

the effective fl/lbs of torque put to the ground with 3.55 gears and 225 ft./lb is about 800 ft/lb.... the same torque with 3.70 gears is 832 ft/lb.

considering that accelleration is a function of power, gearing, and weight, it is easily concievable that a small cubic inch engine such as a 302 with a large (30-30) cam can out perform a larger (327) engine with a smaller (LT1) camshaft... even with equal gearing...

This is also why I feel that dyno numbers are great references, they don't tell the entire story, especially when considering drivability.

my Z has 4.10s and a wide ratio muncie (ordered that way from the factory) doing the torque multiplication of 2.54(first gear) x 4.10(rear axle ratio) x 219 ft/lb torque at 1700 rpm equals a total of 2280 ft/lb to the ground....

using the L76 standard gearing of 3.7 and a first gear of 2.20, you'd have to make 280 ft/lb just to equal that performance at 1700 rpm, not even including weight. 280 is more torque than both the L76/Lt1 engines made.

While this isn't a fair comparison, it is a reality when looking at these cars... and considering that 3.55 gears were available, it is easy to see why you might not like the performance of a stock SHP car. LOL

Also, my dyno numbers are Standard with a correction factor of 1.03.l

The other dyno sheet that Duke was referring to is SAE numbers. with a correction factor of 1.06. I'm not sure how that compares, but if that narrows the gap on these motors comparison, i'd like to know about it.

Thanks

Aaron

63 340HP

The 1.06 (and 1.03) correction factor is used to adjust the numbers to what should be expected if the test were under SAE temperature and barometric pressure conditions (reference lab conditions). The 1.06 number corrects a warmer (less power) weather condition. In both tests the actual numbers were "corrected" upward (6% and 3%) compared to the actual as-tested reading to provide a better gage of what the engines should have performed in a Lab with effective environment controls.

You contention that the torque at the rear wheels for a given road speed is what matters is valid (if I may apply your comments to road speed rather than engine rpm).

Those of us with 4.10 & 4.56 gears and a 2.20 low (my L76 included) have to compromise performance at low road speed to extend the performance past 120 mph (past 6500 rpm). The consideration that I can blow away the standard pizza cutter 205/70 tire traction with ease, even with the less impressive low rpm torque of the '097 or '30-30 cams, may make the compromise assumed with "lost" low rpm torque moot. The LT1 may still be the best balance of torque across the widest rpm band (and the best for a street car), but if I cannot hook the LT1's extra lower 500 rpm to the ground (or the tires, rear axle gear, and low trans ratio cannot exploit it) I need to look elsewhere to best match the engine performance with my usage.

.