Patrick G

iTrader: (14)

I got a call several weeks ago from Coach 02 Z28 A3. He was going to be installing a fresh set of valve springs and timing chain on his 347 cubic inch bracket motor and thought a cam swap might be in order.

Coach's motor is a 13.5:1 forged 347 from LME that runs ported 5.3L truck heads, FAST intake, and a Cam Motion 244/249 .643/.644 112LSA +0 advance cam. He also runs a TH350 trans with a 5000 stall race converter. Needless to say, it's not built as a dyno queen, but a strip warrior. It's been a solid combo that has taken Coach to consistent 10.20s at 130mph. On 98Aggie's dyno, the combo put out 470rwhp/408rwtq.

After spending time with Billy Godbold at Comp Cams (their chief lobe designer) in December, he mentioned a family of solid roller lobes that were compatible with hydraulic lifters. He said very few people in the country were running them. According to Billy, these lobes have ramp rates that aren't as aggressive as some of the "square" hydraulic lobes, but they would rpm much better.

So after looking at Coach's current set, I decided that we could pick up some mid-range by having an earlier intake valve closing point and by using a longer exhaust lobe (with a higher revving solid roller lobe), we could carry power better after peak. The approach worked. The cam is a 245/254 .643/.648 111LSA +3 advance solid roller cam running stock rockers and Comp R hydraulic lifters. One half turn of pre-load. AFR 8019 dual valve springs.

The chart below shows the before and after of the cam swap. Same dyno. If you are wondering why there is a dual peak, remember, this is an unlocked torque converter. The 5000 stall converter does not couple up until 6500 rpm. After that, it's fairly efficient. Check out the better mid-range, the higher peak power and the extended power range. For those who can't read the chart, the before power was 470rwhp/408rwtq and the after was 498.9 rwhp/421.6 rwtq. All this from a cam that to the uneducated would look almost exactly like the one that got taken out. The moral of the story, don't look just at duration and lift when choosing a cam.

hellbents10

iTrader: (10)

Nice results!

Tom@SpeedInc

iTrader: (5)

great RPM, good work

Patrick G

iTrader: (14)

Keep in mind, 499rwhp through an unlocked 5000 stall converter and TH350 with slicks on the rear is soaking up a LOT of power. Had this been a manual transmission setup, the numbers would have most likely been in the 560-580rwhp range.

STEEPSS

iTrader: (30)

wow those are some awesome numbers Pat! Once again, knowledge prevails.

NightMoves

The chart below shows the before and after of the cam swap. Same dyno. If you are wondering why there is a dual peak, remember, this is an unlocked torque converter. The 5000 stall converter does not couple up until 6500 rpm. After that, it's fairly efficient. Check out the better mid-range, the higher peak power and the extended power range. For those who can't read the chart, the before power was 470rwhp/408rwtq and the after was 498.9 rwhp/421.6 rwtq. All this from a cam that to the uneducated would look almost exactly like the one that got taken out. The moral of the story, don't look just at duration and lift when choosing a cam.

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I'm not sure how you are getting the results shown on your graph? When making a power pull on the dino with 4L60 & stall converter I unplug (or pull the fuse) to put the tranny in manual shift. bring it up to about 3,000 in 2nd and shift to 3rd (which is 1 to 1)then stand on it till the revlimiter kicks in. For me this graphs a good solid pull all the way through. How are you doing yours?

Patrick G

iTrader: (14)

This is a Turbo 350 transmission with a manual valve body, not a computer-powered, electronically-shifted 4L60E. To dyno this combo, you shift the vehicle into 3rd gear and stand on the gas around 3000 rpm. With a 5000+ stall, it's difficult to get any kind of hp or torque reading until above 5000rpm.

Black02SLPSS

iTrader: (5)

Out of curiosity, what is the expected valve spring life on that combo? I know its set up primarily for racing but im just curious about that aspect of it.

Patrick G

iTrader: (14)

Coach plans on changing springs again after 200 passes. In truth, this combo is milder on the springs than a number of hydraulic lobes on the market. If this were in a street car, I'd think you could easily get 15-20k miles out of a spring set.

allngn_c5

iTrader: (3)

245/254 .643/.648 111LSA +3 advance solid roller cam running stock rockers and Comp R hydraulic lifters

Wow Pat all that in a 347......thank god its a bracket racer, and not a street car.

Anyways, very nice gains. Should we assume this bracket racer is going to dip into the 9.9's now ??

Black02SLPSS

iTrader: (5)

Very nice. Looks great to me. Makes me wonder if we will start seeing more solid roller cams with hydraulic lifters.

dlove

iTrader: (23)

great results!

Coach 02 A3 Z/28

iTrader: (10)

No track times today. The weather got us. We hope to race tomorrow(Sunday 3-15-09). If we race tomorrow, I will run both Top Et & N/E to get more runs on the new set up.

Coach

Coach 02 A3 Z/28

iTrader: (10)

Well, the weekend is a washout. We will try again on Friday March 20th at HRP.

Coach

WKMCD

iTrader: (2)

Don't tell me there are lobes other than XE, XE-R, XFI and LSK...

I don't know what lobes were used for my cam but I couldn't find anything even close in the Comp catalog.

Nice numbers Patrick.

Old SStroker

Maybe it's the hydraulic roller lifter on a solid flat tappet combo? AKA the HRSF lobes. They are on an unpublished page in the CC Master Lobe catalog Addendum LXIX.


With your cam guy anything is possible.

How does it run?

NemeSS

iTrader: (127)

intersting......
what rocker arms were used?
would these type cams be compatible with say, ls7 or caddy lifters?

slowandrichws6

iTrader: (2)

great results!!