No 6 oh no's POJ auto was in the same range.

There's no difference.

 

Yeah, I just have a POS 48RE that every one knows doesn't work right.


I cheated a little bit also, I run a TC lockup switch. Without it you will never see the potential as anything under 70 mph or 2200 rpms will just cause the trans to downshift. If you look closely at that chart the run starts at 1700 rpm's. Between the 50% defueling under 1800 rpm's and the rest that happens under 12 psi boost it is impossible to get any power going. I start my run at about 50 mph and 15 lbs of boost to get a decent reading on what the engine will develop for a power curve. Any less than this and the engine can't pull thru the brakes even on the rollers.

Oh yeah, my truck had a shade over 50k when this was run. The fallacy that the auto robs so much more power than the manual is just that. Tired worn cliche it is, but it is gospel to some.

This just kills me every time I hear it. Even with the hard evidence clearly displayed we are back to the same tired BS, "yeah, the TQ peaks at 1600 so thats where to drive it". Cmon!!! Read the sheet! The TQ does NOT peak at 1600 or under 2000 rpm's. TQ peak is clearly in the middle of the range at 2400 rpm's just like the manuals. In fact you cannot even began to get these trucks to pull under 1800 without nosing over like you threw out an anchor, and, with an auto it ain't ever happenin' cuz it will drop a gear. Even with a lockup switch you drop under 1800 with a load and any grade or a stiff headwind and you are done for maintaining speed. The TQ may be there but that don't roll the truck, HP does and it ain't there due to defueling.

HOV, the ECU has several checks on the fueling curve built into it. Under 12 psi of boost you get only a percentage of demanded fuel. Another check point is 1600 rpms for a percentage change then the 1700 to 1800 rpm range is another bump that puts onto a decent profile until 2950 when it falls off again. Look closely at the HP line and you will see a pretty sharp ramp between the 1700-1800 range. Another check point is tied to wheel speed as generally you cannot power brake these trucks and spin the tires. At full throttle against the converter with the brakes holding the truck, you get about 2100 rpms, just under what the converter stalls at.

 

Hey, thanks for a very informative post. I guess it makes sense now why my truck is completely gutless for the first few seconds off the line, then really turns on once I get past 1800 RPM... I thought it was turbo lag but now I guess it's a fueling issue.

I kind of like the stock setup though... it does seem very protective of the driveline. If the truck is really to hit 500K+ miles with no major work, it's probably best to leave it like it comes from the factory. Any tweaking will definitely increase the chance of something breaking, and it pulls just fine at speed anyway.

Another thought: with the defueling at lower boost levels, it seems like a boost fooler would actually make a stock truck perform worse. Hmmmm...

 

I notice a SLIGHTLY longer hesitation right off idle with the Quad boost fooler when the engine is cold. Once it is warm I have to try to find the hesitation.

It is not an issue because I don't jack rabbit the starts and never really look for instantaneous acceleration from a stand still. I have gotten used to driving the truck accordingly.

The boost fooler should not effect the low end as it is just limiting the max voltage the ECU see's so the WG doesn't open. The lower voltage readings should be OK but it doesn't always work out that way from what I hear. I talked to Quad a bit about what to expect both bottom and top en wise and his experiences were it increased the lag on the bottom end a bit and would max at about 35 psi on a stock truck. He was pretty sure I would need a box to add fuel to get it to perform correctly.

For the most part the bottom end lag is only minor and I can break 40 psi with stock fueling. My truck runs just a little bit better than the normal 05 does, for some reason. I am also running a RokTek timing sensor advanced about halfway. Too much timing rattle at full advance. Gutted TQ tube, a better flowing air filter, and a Borla muffler.

The real difference was noticed when I had the CP3 replaced for leaking. I immediately noticed more low end grunt, better towing operation, and a noticeable increase in timing rattle and engine noise. As far as I know, and I asked, the ECU has never been flashed. I don't know what the difference in the CP3/FCA combination they replaced the old one with is, but, it is different in a good way.

The CP3 still leaks a bit when the average temps get lower in the winter but I will live with it or reseal it myself before I take it back for anothe one. I LIKE the combination I have stock and will know soon if it responds as well to programmer and/or box. I suspect this has something to do with seeing the better response with the boost fooler so it may not work the same on another truck.

 

I have the same two mods: Rokktech and Quad Boost Fooler.

I did notice a little more lag on the bottom end when I installed the Boost Fooler, but on the flip side it seemed to wake up a little at higher revs. I'm sure the lag has to do with what you said earlier: partial fueling even at higher throttle positions for lower boost levels... basically, the Boost Fooler would keep the fueling down a little longer than normal because it's reporting less-than-actual boost.

Come to think of it though - this should cause a little better fuel mileage around town, but give better performance via more boost under load... which is exactly what I'm after anyway.

 

The Roktech is probably what caused the loss of bottom end. AFAIK advancing the timing will increase mileage and reduce EGT's, but you'll also lose some bottom end power.

 

I think the stock TC stalls way too high... the HPCR makes 400 ft-lbs of torque at 1500 RPM as measured at the rear wheels... ~ 2200 RPM stall is just too long to wait for me!

But I know DC did that to help make the tranny, etc. last through warranty.

 

Actually, the RokTek made a noticeable positive difference in bottom end power withthe original CP3 and FCA.

Not so much with the new pump though. Had to back the sensor down to get rid of the rattle that wasn't there before but low end is still better with it.

The lag is definitely from the boost fooler.

Stall is not really the issue, the lousy TQ multiplication in the fluid coupling is the culprit. Fix the fluid coupling, the stall will automatically come down, and the low end is much better suited to the engine. However, that leads to emissions changes and parts breakage.