Waking Up a Turd
Im In Medicine Hat AB. 2260 Feet
Ouch! yur in trouble; I'll redo the pressure calc for that, then I'll be back.
averaged 130PSI. with 2 cylinders at 125, and one at 140.
I love the Hat. Got a hi-school friend in Redvers.
You got thee problems, Two covered by
@RammerJammer75
Namely 1)too much cam for the pressure ,or said another way; not enough pressure for the cam. And 2) not nearly enough gear for 82mph.
But I've already talked about the really big deal, not enough revs.
In the dragrace situation;
The lack of cylinder pressure mostly affects your performance below about 3500; and you can fix that with a hi-stall TC.
At the top of the track; the highest Mph will come with the engine in the powerband, and thru the traps, just as she has fallen off the cam. For 82 mph,and the 284 cam, that might be 3.55s for 82=5750@10% slip in Second gear. But hang on a sec;
If you shift that thing where it wants to be shifted, namely ~6000 on the 1-2 and trapping at ~5600, then that is gonna push the trapspeed up, and you might run outta gear with 3.55s, and be forced into Third. The engine rpm will fall into the basement, way off the cam, and then you are just driving to the finish-line. To trap properly, with that combo, in third gear, is gonna take a lotta lotta gear. For a streeter, waaaaay too much.
So, IMO,
If as you say, this is
For a Streeter;
then put drag-racing on the back-burner. Build your combo for street, and let the track be whatever.
Ok so with that in mind; Pay attention to your driving habits and style. Find out where your engine has the right amount of power for you NOW; as in what gear at what rpms. And where it sucks. Cuz the fixes are different, for different situations.
I am a streeter too. And I can tell you right off, that your pressure sucks,lol.
I weight about the same or maybe a lil lighter at 3650 me in it. My car spins any size street tire I can get into the rear tubs, to well over the speed limit anywhere in Alberta.
It has a 360/A833/3.55s/ a 276/286/110 cam. ...... and 180psi (alloy heads).
You have more cam, more stall, and more TM(Torque- Multiplication), and more Effective TM to the road.
What you don't have is pressure and rpm. And I don't recall seeing Headers and free-flowing duals.
With iron heads, you want the pressure to be as high as possible, until it hits the detonation wall, and that, with open chambers is gonna be about 160psi, for 91 or better gas. Subtract 5psi per grade of gas. If you want to run 87 gas at WOT with full timing, you will want to run 150psi or so. Add 5 psi or so for a tight-Q design, which you don't have. Ok so , with iron heads
160psi will be very strong.
150 will be adequate
140 will be typical , ho-hum
130 is already sucking
120 is totally feeble
Your Static Compression ratio, AND your cams ICA, or Intake closing Angle,
TOGETHER, determine how much cranking pressure your engine will make. The bigger your cam is, the higher your Scr will need to be, to make the target pressure.
Since you plan on tearing the engine apart this winter, that will be the time to fix this.
Moving on, I feel, for a streeter at 2250 ft elevation, that 284/484/108 is a tad too much. Yes at 4400 or more rpm, it's a lotta fun, but it sacrifices everything below 3000 to get it. And yes, you can put a 3000TC in the trans to eliminate that. But unless you pay the big bucks for one, it ain't going to help your already terrible fuel economy. Besides 4400 in first gear is about 40 mph. So unless your tires spin, that's a long time to wait, to get to where the power starts. Yeah/no, that ain't my cup of tea. When I hit the gas, I expect to strike terror in the hearts and minds of all that hear it. I expect thunder, lightning, and excessive wailing of tires, with accompanying tiresmoke. Ok so maybe a bit of exaggeration there.
You can do all that with your truck right now, with 4.30s and a 3000/3500TC.Even with your 130average psi pressure. But how many miles a week can you afford to drive a thing like that.
For a streeter, absolute power is IMO not the Holy Grail. having the right amoun of power in second gear is. Once you get the pressure up a lil, first gear is gonna do a lotta spinning. So second gear is gonna be the gear you are gonna mostly be in. With 3.23s, you are looking at
30=1700,40=2250, 50=2810; Waitaminute; you see a problem here?Yeah/no; your 360 is not a diesel. Ok so Second gear is NEVER gonna work for anything but cruising with those 3.23s. And no other 3-series gear is gonna make it much better.
So that puts us into first gear. Still with 3.23s and with 10% slip, then;
24= 2500, 30=3130, 36=3810, 42=4400, 48=5070, 54=5710
So riddle me this; where does your 4400 to 5700 cam fit into this?
That's right; from 42 to 54 mph.
You can use a Hi-stall to get you to 30 in a hurry, but from there to 42,it's all on the engine.
So tell me, how often are you gonna be between 30 and 42 mph?
I'll guess at least as often as from zero to 30, and together those two might be ...... say 95% of the time, jus guessing. So, would it not be in your best interest to build your combo to have power in the area that you actually drive, than to optimize it for an engine speed that you will rarely see on your tach.
In Second gear with 3.23s@10% slip;
60=3700, 70=4330, 80=4950. Do you see 5700 there anywhere? Hey; I'm not being a smartazz.
The fact is that if the tires don't spin, you got a long wait to 42mph, then you got a quick scoot to 54mph, than yur dead in the water, until 70 mph, when the cam starts waking up again.
And if the tires do spin, spinning ain't winning. But it sure is a lotta fun.
So , if this making sense, then what's the cure?
This right here is a great start;
It honestly sounds like it's over cammed and under geared right now. If you have J heads, you might port them or leave them for now and get a bit smaller camshaft. Might be able to trade the 3.23 stump for something in the 3.55-3.73 range.
You gotta get the power down to where it is readily available, even it sacrifices dome absolute power, to get more power at lower rpms... which is where you are gonna be most of the time.And then make the reduced power zones shorter, with a bigger rear gear. The Gear chosen, will partly determine the cam. And the cylinder pressure will lock it in.
So without an overdrive, you might have to sacrifice hi-speed touring, to tighten up the rpms.
Lets try my favorite city gears of 4.30s.
Currently, your first gear road gear is 2.45x3.23=7.91.
With 4.30s it would be 2.45x4.30=10.54
That is 10.54/7.91= PLUS 33%. So your engine, by comparison, is gonna feel 33% bigger, torquewise ....... ANY TIME/ALL THE TIME. But right now, under 3000, she is feeling like a 5.2M,sooooooo now first gear is gonna be feeling more like it outta.
Lets look at the new First-gear(still 10% slip) rpms;
24=3340, 30=4170, 36=5000 42=5840, and in Second
42=3460, 48=3950, 54=4440, 60=4940, 66=5430, 72=5930
Look at the blue numbers; this is now where your 284* cam is on the pipe.
So as you can see, below 30, she is still struggling. Now you have a choice; Either keep the 284 and get a hi-stall. or keep the current stall, and bring the power down .
Le try a cam two sizes smaller; say 270/276/110 ( this is what I have). This cam peaks at about 5000, starts at 3500, and pulls forever with Edelbrock heads. Ok say 5500 with good heads. And again with the speeds;
24=3340, 30=4170, 36=5000 42=5840, and in Second
42=3460, 48=3950, 54=4440, 60=4940, 66=5430, 72=5930
Ok now we have it covered from 24 to 66 mph. The factory 2400 while not terrific, remember we now have a starter gear of 10.54 so it's only gonna be down there for a few micro-seconds.
Ok but, from 284 to 270 is two cam sizes; isn't that a big power loss?
If you are looking at just the engine, then Absolutely yes it is. But about half of what we lost on the top, is now on the bottom where we really needed it.And we multiplied that by plus 33% with the 4.30 gears! So if you convert the horsepower, back to torque, you will find that you now have waaaaaaaaay more average torque from stall to shift rpm, than you previously had.
But, here is a bonus,by slipping in the smaller cam your Ica is gonna come down, about half the difference or 14/2=7*. And that is gonna pump your pressure up about 10 psi... So now, your average is 130+10=140; what did I say that was? IIRC I said "adequate". So with no other changes than the cam/kit, you have transformed your slug into a tire frying slingshot.
And another nonus is that your 82mph trapspeed might climb to 86 and now in third gear at 4900 just about right on the power peak of that 270* cam!
So what did we spend?
a cam/kit
a 4.30 gear
lessee what else?
OkNope, that's all I got. lol.
Well, you are gonna have tirespin problems; so that's gonna cost some money to deal with.But you would have had the same problem with a hi-stall, so in my thinking, I won't count it,lol.
That leaves it up to you, if you want to chase a lil more pressure.
I would, but I turned into a pressure freak the first time I nailed it.
And finally; I said all that to bring you here.
You don't need the 4.30s and you don't need the 270* cam. I used those to introduce you to a different way of thinking,namely; putting the power where you need it, and saying to heck with absolute power.
What I would do; first, my 270 cam was about
[email protected]. This is a terrific fun street cam. In your case, I would get a same
[email protected] but in a solid lifter cam. This will bring your pressure up another 5 or so psi, so now 145, dangerously close to being the max for 87E10 with open chamber heads.But the thing is, the 270 Hydro doesn't actually close the intake anywhere near the advertised number, it could be 10 to 15* later, which kills the low rpm pressure, beyond what the Wallace Calculator can estimate for. Whereas with a solid, you tell the intake exactly when to close. And that might get you a few more psi, say 148 now. And then some new rings might get you into the 150s, I guess time will tell.
And with the pressure now cooking, you won't need the 4.30s so much. They are still the right gear to pull it all together, but, you could sacrifice some of it.
What you could do is grab an A999 with it's 2.74-1.54 1-2 split, allowing the 4.30s to become 3.84s for the same First road-gear, but that's gonna make a big difference at 60mph. But the A999 has a slightly wider 1-2 split, so, in compensation, I would order the solid lifter cam on a 112LSA. This will reduce your pressure some, maybe 2psi, so back to 148. No biggie. Because this solid lifter cam will make a stronger bottom end Ima thinking we can drop another size in rear gear, to say 3.55s. Or we can up the TC to 2800, and leave the 3.23s in there..... see how this works? always trading.......
So where are we now?
Solid lifter cam,kit,and adjustable valve gear
An A999 trans.
And,....... OkNope nothing else.
Don't care about the intake/any 4bbl, headers optional but recommended, for sure a big free-flowing dual exhaust to let that solid-lifter cam do it's job, Hi volume fuel pump for that long third gear pull,3/8 fuel-line optional, good coil/any ignition,
brakes. Hyup, yur gonna need brakes. and big front tires, cuz the back ain't gonna be doing nothing except skidding when the front don't bite. And those pesky curbs keep sneaking around every corner, lol.
Ok so, now you get to think it over, and I get to go have supper,lol.
No editing on this post, if I typo'ed you'll have to figure it out,lol.
