Confused with throttle response

[Camp]

Ok guys, let me pick your brains for a minute. I am trying to figure out why my truck has much less throttle response than my roommates truck. My truck is in my sig and this is a comparison running the Juice/Attitude on my truck.



My roommates truck is an '02 3/4 ton short bed extended cab, 6-speed. He has a DD True Torque Module on it and an open air fliter. I think it is a K & N but, don't remember for sure. He also has hummer rims on it with the 35's and 3. 54 gears. My truck has 3. 73 gears.



We had to switch trucks the other day so he could drop mine off for some hitch repairs and I noticed a HUGE difference off idle in throttle response. In his truck, when you touch the go pedal, you immediately feel the torque and it takes off. In my truck, the go pedal feels a bit mushy until is gets spun up.



Is the difference due to all the emissions programming on the newer trucks? Is it something to do with the common rail injection? I ask that because my Dodge has similar throttle response to my Duramax that I sold.



We were talking last night about this and he noticed the difference too but, neither of us are completely sure why that is. He did say that his truck was similar in throttle response from idle as mine when it was stock. He said the DD box is what made the difference on his.



I just don't understand why the Juice w/ Attitude would not produce similar results unless I am too stupid to use the box properly.



By the way, I had the Juice set on level 4 when he took my truck, that way it would be making similar power to what we know he has put down on the dyno.

 

[rbattelle]

I really don't think you can make any kind of meaningful comparison between the two vehicles. They have different turbos, blocks, pistons, fuel system (high and low pressure), intercoolers, radiators, fans, and programming. Even the TPS sensors are different.



I don't see any way to draw any meaningful conclusions from comparing how the throttle "feels" between them. Am I missing something?



-Ryan

 

[Camp]

I knew there were differences but, I don't really understand why the new engines would make more power but, have less grunt. Why make the diesel perform more like a gasser? My question is more to the effect of; is there something else out there to get more bottom end out of this motor or is the programming in the ECM so EPA friendly that you just get to live with it?



Trust me, it is not just "feel". My truck falls on its face until it is making somewhere around 8-10 lbs of boost. His will put you in the seat back right from idle.

 

[CLAYTON]

I noticed quicker throttle response when I added a BHAF and exhaust. I believe that it helped my turbo spool quicker in-turn making the throttle feel better. On your Attitude what setting do you have you "low boost fueling" on?

 

[Camp]

That "low boost fueling" setting confuses me. Every time I set it, it goes back to one. I need to get the manual out and make sure I am not doing something wrong with it.

 

[CLAYTON]

I think you can set the low boost fueling for each power level... So if you set it for 5x5 and then you go to level 4 it will probably be 4x1 unless you set it to 4x5 for the power level. I have the beta box so mines a little different. Can someone who has a production box chime in on this?

 

[Daimler Dan]

Camp,



While I can not speak for 04. 5's, I know the 03's have a lot of controls to keep low-end response lagging. I am not sure if it is emissions, or drivetrain control, probably both.

On the 03's, I am seeing torque management (auto's), air/fuel ratio controlling, and timing/fuel pressure dips that hurt low end response.

Find a way to eliminate these (not so easy. . ), and your low end throttle response will liven up.

 

[Badunit]

I knew there were differences but, I don't really understand why the new engines would make more power but, have less grunt.

Don't confuse off-idle throttle response with low-end grunt. I understand what you mean, though. The fueling seems to be turned way down right off idle. I would have thought your Edge box would have fixed this little issue for you.

 

[Donn]

I don't have any complaint with my idle throttle response, if i push the pedal to hard I just light up the tires. It is go right now. I don't know if it is the bully dog programmer, but it is set in the middle setting (90) hp. I put the aFe intake on first, and noticed some difference, but the low end throttle response after the bully dog is awsome.

 

[Camp]

Don't confuse off-idle throttle response with low-end grunt. I understand what you mean, though. The fueling seems to be turned way down right off idle. I would have thought your Edge box would have fixed this little issue for you.

I agree, there is plenty of bottom end in the motor but, that was the best way I could think to explain it. Basically, if you are pulling out in traffic, mine needs to make boost before it will get out of its own shadow but, my roommates truck begins to accelerate hard right from the initial touch of the pedal.



Thanks for the responses guys! It sounds like I am not nuts nor is there anything wrong with my truck, just that the EPA has had their way with it

 

[robertyoke]

camp



I would guess that the diffrence in compression ratio may be all it takes. you say that it feels like it makes less power right when you touch the throttle before the turbo spools, like his 02 makes more power at idle.



have you both had the trucks at summit county for a little comparison and then at sea level. my 03 is a tire smoking animal at sea level, and at 10,000 ft it is pathetic turd out of the hole. I wonder what the diffrence would be between your two trucks at those altitudes.



-robert

 

[Camp]

Interesting. I haven't paid much attention to my truck when it has been at lower elevations. We pull to California a couple of times a year with it but, I always have the trailer hooked up so, no high speed passes with it. I leave for Georgia with my enclosed on Friday. Maybe while I am down there, I will have to unhook and make a couple of WOT passes with it.



Out of curiousity, since I am ignorant to it, what are the compression ratio's for the two trucks? I didn't know there was that much difference in them.



Thanks,

Camp

 

[robertyoke]

I dont know off top of my head but, the vp pumped h. o. were high compared to the vp s. o. and the common rail I think is between the two. I may have to look 'cause I am going from memory and it's not what it used to be.



-robert

 

[pecandude1]

my 03 with only 250hp would jump out a truck length in a half from a dead stop over my 05 with 325hp then the 05 would pass the 03 (their both autos). but thats not near as bad as my 05 duramax from the time you floor the pedal to the time you have full power you could count to three (seems longer)

 

[Scrappy]

the computer in the '03 is set up to not fuel hard until it sees boost from the turbo. the Van Aiken C3. 1 is supposed to help wake up the low end.

 

[pecandude1]

the 03 is fine. its WAY! faster off the line than my 05 that has more power.

 

[JTurk]

I can echo Camp word for word on the lack of low end on my 04. 5 Dually LB. I was used to my 96-2500 with Banks Power pack. A few weeks ago I added one of Quad's non-adjustable towing modules and life is MUCH better. The problem now is that I have to let off by 2. 5K in order to shift before the boost goes over 40 lbs. I don't need a turbo bill at 18,000 miles!

My thinking that the low end power loss is all EPA, which is why the mileage is lower. Quad seemed to help that a bit too.