Homestead

There was a dyno day today at a local performance diesel shop today and I had a chance to run the rollers.<br>Stone stock, my truck put 179hp and 516 ft lbs of torque to the rear wheels. We plugged in my EZ box and it went to 206 and 700 respectively.<br>Now I just have to wait a week and a half to get the 4&quot; exhaust and cold air intake installed and see where the numbers go from there!!!<br>Just thought I'd let you guys know! ;D

chuck3

The EZ didn't give you very much HP did it? Mine dynoed 178 stock and 236hp with the EZ. I have heard that injectors work better on the HO's than the boxes, must be something to it.

Homestead

We noticed the HP was down, but we also didn't install the boost elbow yet and I am running a larger tire ( 305/70 instead of stock 265/75) Dyno is also at 4000 ft of elevation which will make a difference.<br> I'll post the numbers, stock and all toys installed after the 16th when it will be dyno'd at sea level and then it get's dyno'd again at 4000 ft so we can compare numbers. The local shop is interested in the difference.

chuck3

Don't know if you will notice a whole lot of difference, I'm over 4k ft here too. Lets us know tho.

Lil Dog

I don't want to throw stones here, but &quot; Their &quot; dyno is always showing huge torque and low HP.. I would be careful on their numbers... <br><br>For comparison, at our dyno day we saw consistent numbers from stock PSD's at 209 and Stock ETC's at just over 200 at the rear wheels.<br><br>Heck even my 93 does over 200.. THe G-tech also agrees with this dyno...<br><br>Be careful Homestead....<br><br>J-eh

Scotty

My stock ETH 6 spd dyno'd at the same elevation in the same town on a dynojet was 221 at the rear wheels bone stock but no way did I have that torque. I also had 221 HP stock in Vegas. I never could figure out how the torque and HP numbers had so much of a spread where you did your test. Real world will tell ya.
Also, do not expect any power increase with an exhaust or an intake. The only time you might see some HP [less then 10] from an exhaust upgrade, you would have to be at the limits of the 3&quot; exhaust...and that would have to be at the 325-375 HP range. Food for thought.

Your numbers at sea level [I am guessing in BC...abbottsford?] will be higher by a small amount because of elevation. The air is more dense out west.

Your RWHP would be in the 220-245 range on a stock ETH. With torque in the range of 460 lb ft. Some ETH trucks have some high factory HP numbers.

Add the EZ and it should be around 30 RWHP higher and torque in the range of 510...give or take a bit.
Good luck with your testing. ;D

Bart Timothy

What gear was used during that dyno run? How was the torque calculated? High torque and low hp sounds like a lower gear was used, or a wrong reading on the rpms, wrong math calculation, or something along those lines.

Homestead

I wondered about the low HP number ??? I know there is driveline loses, but 60 some HP thru a manual trans. I am running a 3:54 gear with tires about an inch and a half taller than stock, so that would make a difference but not that much. <br> I know every dyno is different as well as a dyno operator is looking for a smooth curve not a spike. They did 3 pulls on the truck when in stock trim and the 2nd pull gave the numbers I presented. With the EZ, it was pulled twice. The first run was aborted because the truck wouldn't load the rollers, it just hazed the tires. There was a different truck dyno'd between my sets of pulls.<br>There were 3 other 02 HO Rams run that day, all with stock 265/75 rubber, and they all ran similar numbers with and without the EZ. Their HP and Torque were slightly higher, given the tire size. At least it gives my numbers some consistency, not a &quot;fluke&quot; reading.<br>I'm not taking the numbers and &quot;living by them&quot;. As long as I'm happy with the seat of the pants test, what more can I ask for! It looks good, goes good, good enough ;D<br>All these mods are honestly being done to, yes, give me a little more poop, but more for reliability and mileage. More air in and out means cooler running temps, exhaust brake saves me some service brake wear, EZ gives a little more snort.<br>I'm happy!!!<br><br>I'll keep you posted on the changes, thanks again for your input, it's much appreciated!

59mega

the ez will give you about 35 peak hp. but at 2000rpm it willl give you over 60. <br><br>jim

SmokinShaker

What effect do larger tires have on the numbers? Will they be higher or lower?

chuck3

Larger tires will cause the #s to be lower depending on how much bigger around they are, its like putting higher gears in it.

SmokinShaker

...uh...guess that was a dumb question huh : I hate it when that happens...

dieselgeek

Was this a dynojet dyno?

That WILL account for inflated or skewed numbers. I've been to a few dynos now, the ones that seem best are Superflow and Mustangs.

Read up on Dynojets - not good for tuning. They spin a &quot;known mass,&quot; not a mass that's equivalent to running your truck down the road.

We found this out the hard way - tuned a Lightning pickup on dynojet by CHT/EGTs, and found that the real world added about 300 degrees F higher temps - and could have burnt holes in pistons had we let it run lean much longer. Oh well - that's a topic for another forum...

doug

[quote author=chuck3 link=board=4;threadid=5599;start=0#51715 date=1034375388]<br> Larger tires will cause the #s to be lower depending on how much bigger around they are, its like putting higher gears in it.<br>[/quote]<br><br>maybe -- depends on the machine used and how the dyno test itself is conducted. In theory, you are right that a larger tire will contribute torque multiplication and cause lower torque to the road. I suspect, however, that real world dyno tests correct for that.<br><br>The transmission gear, the rear end, and the tire diamter all contribute to torque multiplication and actual torque delivered to the pavement. I could be wrong about this, but I believe that the dyno simply compares the engine rpm to that to its own roller rpm and bingo--you have instant normalization of drifveline configurations. So the dyno doesn't care about your gears and tires -- you just have to tell it what the engine rpm is and it figures out the rest. So if that is the case then no--larger tire sizes will not impose a different final drive gear ratio and cause a lower torque reading. There may be other tire-loss related factors contributing, but tire height is not one of them. That is, unless I'm wrong about the way dyno test are actually performed.<br><br>

AlpineRAM

Well any dyno can just measure or calculate the force applied and the speed of its drum. The force is either produced by a brake or by inertia of the rollers. A certain force@ a certain speed is power. That is on the wheels. If you measure engine RPM you can calculate torque. And print some blue and red curves. I used several Bosch dynos (calibrated for proof of evidence in court) which used brakes (electromagnetic) I found that if you let spinup happen too fast on these dynos you'll get weird numbers for turbocharded engines. (EG boost comes up slower than vehicle accelerates). Bigger or smaller tires should not make change your numbers. Actually on an inertia dyno bigger tires should increase the numbers because you have more time to get up to boost. <br>Maybe somebody can make sense of this garbled english...<br><br>AlpineRAM