Topic: Message #1126130

[Snowtoy]

Hi Snowtoy,

LOL…. Your posts read like a person possibly with H.A.S. (Hyper Analytical Syndrome)… I have it. 

 It’s not necessarily a bad thing and seems to be found more often in people with extra brain cells and higher I.Qs. 

Side effect of my education and original career choice.

I did not know about tire sizes not being actual? 

Wasn't an issue anyone thought about, until IIRC Interco made it a marketing issue 10-15yrs ago, some manufactures have upped their mounted sizes to be closure to their sidewall size, others have not.  Overall height is also effected by the rim size, and overall tire diameter, my BFG 33's and 35's both on 15x10's measure 31 and 33 inches, yet the

I’m sure you’ve watched a funny car burn out.  You noticed the tire diameter expanding radically.  That’s what happens, to a lesser degree, to tires running down the freeway at 75 MPH.  Right now my 31” BFGs measure 30” diameter, but they have been sitting for 3 ½ years, and may be a little low on air pressure? I’d make a good guess that if I could measure my tire diameter at 75 MPH that they would be more that 31” in diameter?

Not quite the same thing, dragster tires are usually filled with less than 15ps, most under 10psi, and use nitrogen since it is wont expand much/if at all under heat.

At 80 MPH my 31s are running down the freeway at about 15 revolutions per second, and in this Arizona 100+ air temp, plus the pavement will get 170+ degree F, I would think that BFG rubber is expanding.

If this was happening, there should be a noticeable power loss at that speed, and your speedometer should be off more than just the % between the stock 225's(27") and your 31's.

Your idea to “buy-low-swap-sell-salvage” is not a bad idea, but at my age my clock is speeding up and I’m much more lazy and slower than I was at age 42 - which was my peak! :-

I hear ya, but there is a member on here w/a front IFS section in So.Cal, that can get you halfway.
http://board.marlincrawler.com/index.php?topic=100092.msg247122;topicseen#new

With both my 22R/RE pickups, I never changed the ring & pinion, just ran the stock 4.10s.  I ran 33s on my 85 22R and that did cause a gear ratio issue.  1st gear starts were sluggish and 5th gear was sometimes not useable, and had to use 4th.  But, I got used to it. Since I had lockers front and rear and Marlin Crawler, doing a R&P swap would have been the hot ticket, looking back I’m not sure why I did not.

True. most find 31's and 4.10's tolerable/livable, for the most part, and with the fresh rebuild it may perform just fine.

As I mentioned, yes, a R&P change to lower gearing will be noticeable on your butt dyno, and can move the peak torque to a more useable RPM, BUT…. it still doesn’t increase any power.

On doing an R&R on camshaft, I have only done that while doing a head job.  We have read about guys that have done it without any issues with the head gasket.

It would interesting if the guys that have done cam swaps without moving the head, could comment on that, as I would like to do some cam swaps and dyno tests in the future with my truck.

R&Ring a head on 22RE is WAAAYYY more time consuming compared to just removing the rocker cover, removing the cam sprocket, un-torquing the head bolts, lifting the rocker rack, removing the 3 cam bearing caps, lifting off the camshaft, and then re-assembling.  I could be wrong about that, but that’s how I envision it.

Gnarls.

If you are going to test different cams, then I would wait until you have bought the different cams you are considering, swapone in, tune/dyno, then repeat with the others, after you fond one you want, redo the HG.

One thing you have to remember, often theoretical power/performance gains on paper don't often transfer to the real world, which is why, as you have found, cam manufactures don't/wont state HP gains, only "x"%, nor do many post dyno runs.

I'm looking for as big a power increase as I can get for the buck, and specifically in torque.

Not to beat up the topic, but it is an interesting discussion....  Regearing would not give me any more power.  I can use 4th gear to get the RPM up to a higher torque number.

Spending the money for a gear change, would not be my first choice.  I'd rather spend $112 for the cam, and $600 for a header, 2.25" exhaust tubing, a free flow cat, and a turbo muffler.  THEN, I'd have the increased power I want and would not need to change my gear ratio.

Gnarls.

Once you get the rebuilt in, you should dyno the truck with a set of 225's and the 31's to see what the actual hp/tq loss is, it would give you a number to test your mods against.