Dmitriy

iTrader: (15)

So a little while ago I saved up some funds to build up a decent streetable h/c setup, my research led me to picking up a Texas Speed 228r cam on 114lsa and matched it up with the PRC 5.3l ported heads.

I was pretty happy with the results, expected to hit 400hp, but ended up with 429hp/389tq, which made me happy... but of course, I "needed" more...

The need for more came before any funds were available for buying "more"; throwing more monies into my build to work out flaws was not an option. I did however have a slightly 'larger' cam lying in my garage.

The 228r cam that put me at 429hp was spec'ed at: 228/228 588/588 114lsa, the 228r cam uses the aggresive comp xer lobes. Power with this cam peaked at about 6100rpm

The rogue cam in my garage was reground by deltacams to 228/230 .571/.573 112lsa, and has the less aggresive comp xe lobes.

I attempted to edjumacate myself into cam durations logic, which thoroughly confused my but from what I've gathered from articles and Youtube; I was led to believe that adhering to the following specs would equate to better power:

-More lift would = more valve opening = more flow = more power
-If Intake/Exhaust varience % is lower than 80% than more exhaust durations are better in cam choice (some chevymag)
-More exhaust durations would equate to better velocity.
-Tighter LSA puts power lower in power band.

All this data crunching eventually gave me a headache and made me believe that throwing the 228/230 cam with less lift than what the 228r cam had equate to less power, but I decide to say **** it all and give up the 114lsa for 112lsa just so I can just enjoy a choppier idle for the summer time.

I succeeded in attaining the choppier idle; but I really did not expect to pick up an extra 20hp/10tq out of 2 extra exhaust durations and less lift

Can anyone help explain why?

Dyno comparison between cams:

Dmitriy

iTrader: (15)

BTW - the tune stayed exactly the same between runs, AFR was not accurately recorded in the first run, thus the 10.0 flatline...

Paul57

What is your exhaust set up?? If it is somewhat restrictive then a little more exhaust duration could make a notable difference but 20 hp seems like a alot for 2 degrees. Also, the extra overlap may have helped pull in a larger intake charge.

Your tune is a very large variable. It is disappointing when magazines do cam and head swaps but don't take the time to tune to optimum AFR and power. They share back to back results that are truly incomplete...and most people just automatically accept what the results were because they were "back-to-back".

Dmitriy

iTrader: (15)

Exhaust setup is rather laughable. I am currently running dented/rusted pacesetter LT/ORY, the Y looks very inefficient as the merge of driver side into passenger tube is very perpendicular vs a "V" style merge (if that makes any sense at all)

Dmitriy

iTrader: (15)

All mods starting from filter to exhaust

K&N CAI
Stock MAF
Ported TB
Stock LS6 intake
Stock injectors
Stock rockers
7.4" rods
LS7 Lifters
LS2 timing chain
228/230 cam 5.3 heads
Pacesetter LT/ORY - driver side has a 'speed spike' made with torch/3"clamp/RTV to fix a leak from a bad dent
BBK balancer
T56
Monster L2 clutch/18lb flywheel
10 bolt with a chipped gear tooth
Magnaflow catback

WTR's camaro

iTrader: (6)

if u are on the market i would look into a set of TSP 1 7/8 LT's. i have them on my stock z28 and i picked up close to 25hp(give or take) with full exhaust. i got the LT's, O2 extentions, and ORY all for 800 shipped to my door. they are stainless and the install was a breeze. im not trying tp pander for them as their products speak for themselves, but i have had them on the car for well over a year with 0 rust. just my .02

Dmitriy

iTrader: (15)

I actually have that exact exhaust setup on my wish list - the TSP y merge looks pretty nice.

JakeFusion

iTrader: (7)

More overlap. But I don't see 20HP from the modest gain in overlap. If anything, you barely went any bigger with a much less aggressive lobe.

My next question is what was done by deltacams? They reground - but did it get bigger or more aggressive with their work?

HCI2000SS

iTrader: (2)

The before and after is on the same exact dyno correct? Another question...were both cams verified to match the cam card itself?

Dmitriy

iTrader: (15)

Both pulls were done one the same mustang dyno.

-The 228r pull was done in the morning ~45-50* weather.
-The 228/230 pull was done in warmer weather ~60ish.

I verified the cam card for the 228r cam. No cam card for the 228/230 - but called Delta Cams and they gave me the specs based on the number they etched into the cam - I did not ask what it was reground from though...

Dmitriy

iTrader: (15)

Cams dont sound too much different either, just slightly choppier with the 112 lsa.

Warmed up idling with the 228r cam (dyno vid)
Cold start with 228/230 cam and a few 2k-3k revs -

HCI2000SS

iTrader: (2)

Hmmm... well even if the 228/230 was off a bit upon installation it still shouldn't account for 20 hp lol. How's the drivability compared to the 228r?

Dmitriy

iTrader: (15)

I thought the same thing, but I don't have an adjustable timing set and I think even if I was off by 1 tooth - it would be too huge advance/retard to run right... I just lined up the dots on the gears.

She drives great, its noticeably weaker down low but more violent up top Driving around town she just asks for a slight rev to 1.2k to get off the line smoothly (I do have an 18lb flywheel)

6th gear still does well at 60mph and 1200ish rpms.

HCI2000SS

iTrader: (2)

That's awesome! The drivability sounds very similar to my setup actually. There has to be a reason for that big of a hp difference, but i'm just not seeing it here lol

Dmitriy

iTrader: (15)

The logic that I have decided to accept - (bare with me as I'm a little crazy...)

I think the answer may be in the head flow #'s:

FROM TSP, 5.3L stage 2.5 head flow:

Lift Intake Flow Exhaust Flow
.200" 147 cfm 111 cfm
.300" 206 cfm 145 cfm
.400" 254 cfm 185 cfm
.500" 291 cfm 204 cfm
.600" 308 cfm 223 cfm

Intake flow varience from .200-.300lift = 59 cfm increase
Intake flow varience from .300-.400lift = 48 cfm increase
Intake flow varience from .400-.500lift = 37 cfm increase
Intake flow varience from .500-.600lift = 17 cfm increase

If I was to mentally graph out the increase in CFM between lift values, it would appear like a HP curve flatting out on top (by .600 lift)...

So, maybe with a *slightly* less lift cam, I am capturing the range in intake flow that has the highest velocity?

This is pure speculation and I am not an expert

JakeFusion

iTrader: (7)

No, with more CFM in the head, you actually want more lift, since peak lift is an area where you only "dwell" once. But you "dwell" in the midlift flow areas longer when you have more valve lift.

For example, a .600" lift cam would cause the head to flow through the 291 and 308cfm numbers on your head longer than the .550" cam would. In fact, you'd never get 308cfm with the .550" cam. Also, you'd hit the 291 number twice with both, as the cam opens and as it begins to close. But you wouldn't hit 308 at all or most of the numbers north of 300 with the .550 cam.

Hypothetically, at .550" lift the head is flowing 300 cfm (avg of the .500 and .600 numbers). With the .550" cam, you'd only hit 300 once, but with the .600" you'd "dwell" on the 300cfm point twice, and all of the points above it twice until .600". So that's why just a few cfm between heads can make for pretty noticeable power differences if you have the camshaft, supporting intake/exhaust mods, and CID or RPM to make use of the flow.

Of course, lower lift cams can make more power if they can get off the seat faster and "dwell" in the midlift for longer periods of time due to any number of factors like duration, lobe ramp, overlap cycle, etc.

HCI2000SS

iTrader: (2)

Interesting theory actually, and I think I see what you are saying, but the lift is still pretty close between the two cams. At least close enough to not warrant a 20 hp and 10 tq difference...at least in my mind, but who the hell knows lol. Besides the different lobes the LSA is the biggest difference here from what I can see. Do you happen to know the intake centerline for both cams?

Dmitriy

iTrader: (15)

I see what you mean Jake - that does clear a little mud for me.

Makes sense that a .600 lift cam would allow more time to dwell and capture the higher flow number just below .600

HCI2000SS - I'm not certain on the intake centerline value, will need to dig around to see if I still have the old cam card.

DACTARI

iTrader: (1)

My theory is that with more overlap you've brought the torque curve down into an RPM range where you can actually realize it. Prior to this, you never realized your peak. You would have to have spun faster than than your rev limit.

Oh and black magic.

Dmitriy

iTrader: (15)

Thanks for the input guys, I really appreciate the feedback - just trying to understand what was done right so I can do it more right and get more more MORE!