Before anyone might point me to use the "search" feature, be assured that I have used it and that is now why I have this question.

I have an 02 HD. I understand from reading the HD and L forums that the L can take a 2 lb pully before there is a need for a chip because the factory computer can handle the difference and compensate. I also know that the HD has 2 lb less boost to start with and believe that the HD and L share the same management computer. Does that mean that a HD can take a 4 lb pully with no after market chip and still see the performance gains? I realize that our different SC pully will mean that a 4 lb L pully will not result in 4 lb of boost for the HD so maybe even a 5 lb would work with no chip.

What I am also wondering is whether the HD gets more HP/TQ for the same pully size as compared to the L. I think that as the SC nears its max, each additional lb results in less incremental increase in HP/TQ. Because the HD starts with more room to grow and assuming the L is factory tuned to maximize the point where a pully provides diminishing returns compared to failure, does the HD get more bang for the buck from a pully than the L - i.e. a 4 lb = 15 HP on an L and 15+ on a HD?

 

that 2nd part is a good question. it makes good sense to me. not sure how big a difference there would be, but i would assume there would be a slight one. whether its noticible or not, no idea here

anyway, not sure on the chip part either, but the L and HD have different programs, so if you increase the boost by 4 lbs on the HD, you may want to get a chip just to be safer, and also more gains

 

Great questions and I too do not know the answers. I will add my two cents though.

Just as we enhance performance of our mechanical parts and take care of them with timely oil changes, we need to care and enhance the computers too.

It's not like the old Mustangs where you could just adjust the carb and timing and you were there.

The computers today make 1,000's of calculations given all the information they are taking in from the 100's of sensors on the trucks, thus when we enhance the mechanical parts to the point where the stock computer can't keep up with the mechanical enhancers, it is time to enhance the computer.

I think you will have more piece of mind and your truck will perform better if you get the chip custom made to match your mods.

You speant over $30K for the truck, what is another $400 for a chip that will protect and enhance your investment?

 

thats what i always say when people say that a certain polish or wax costs too much, or they ask if they'd think it would be okay to just use this product of a multi product polish, or mix and match just to save 10 bucks over 6 months time. Whats a few extra bucks, or couple hundered more bucks when you look at how much you payed for the truck. why push the limit and risk screwing yourself in the end? just my .02$

 

I think your assumptions about pulley size, and more bang to the pulley size question is correct.

However...

The computers ARE different. The programming is MUCH different. The timing curves a BOUND to be different, due to different airflows...

Secondly, it is rumoured that the HD has a higher compression. this too would net more HP based on pulley sizes. BUT!!! Higher compression means a higher probability of detonation... the MAJOR cause of engine failure when swapping pullies. Therefore, a chip would be HIGHLY advisable... IMO...

 

There are a couple of guys over on world that are running 4lbs of extra boot with no chip. The oem computer can handle it just fine. There is also a thread over on NLOC. Several folks running 4+ pound lowers on their L with no chip and they are doing just fine. One of the two works for Ford and can tell you that the factory computer program fuel tables are filled in way past the standard mark.

The chip will net you more HP, though, as the A/F and timing will be adjusted for max horsepower.

I would be willing to bet you my truck that you can put a 4lb lower, if not a 6, and still run quite rich on the factory computer. You won't, however, produce as much horsepower as a well tuned chipped vehicle will. The extra horses come from a slightly leaner mixture combined with more timing.


Ken

 

I will have a 6lb lower and chip available if interested.

 

Excuse the showing of my ignorance.....
For a base line starting point what is the configuration of the stock pully set up on our 02's.
Upper = ?
lower = ?

Outnumbered - I am just north of Charlotte; I may be interested in the pulley & chip you have. Please email me with the details.
dinsull@americantiredistributors.com
Pulley, Chip & Cold Air intake are next on the mod list. Getting the truck back today with BellTech 1/2 drop & Nitro Active shocks installed.

 

Dinsull, You have mail.

 

Outnumbered-

If your previous deal falls thru, let me know... LightningDammitt@yahoo.com....

I'd be interested also...

 

Thanx all. I know that a chip is a big help for our trucks so its not out of the picture and I will get one eventually. I am trying to make the additions systematically so that each addition has immediate impact and also does not require the removal or addition of something else - i.e. if I get a chip first then I have to send it in for a reburn when I get the pully etc. I want to put it on and forget about it. I will probably do the basic filter/pully/chip combo but likely over the course of several months rather than all at once.

 

Lower HD pulley is the same as the L. Upper pulley is about 3.25" vs. the L at 2.93"...

That is how you lose the 2 lbs of boost....

Ken

 

Ken and Outnumbered
What are you presently running on your trucks? 8# or something else? I presently also have a 6# and flip chip and am thinking about going to an 8# and another chip (or reburn). Did anyone read the article on supercharged Lightnings in Trucking a month or two back? It was a very good step by step tech write up on our engines.

Treadwheeler-The lower pulley on our trucks is a 7.5", and I believe my 6# is a 9.0".

 

I've been playing around with some numbers - pully ratios and such and think some of the info is interesting.

From reading some older posts, I was able to find that the SC is rated for a max of 14000 RPMs. The stock L with a 7.5" lower and 2.93" upper @ 5000 RPMs will turn the SC @ 12800 RPMs. The HD with its 3.25" upper will only be turning the SC @ 11500. Applying that we see that the L reaches the SC "red zone" with approximately a 3-4 lb lower pully (which measure 8.17 and 8.5 respectively) - 3 puts the L @ 13950 and a 4 gives 14500. On a HD, the SC is still turning only 13900 RPMs with a 6 lb pully - 9 inches. I got the pully diameters from some older posts.

What I think that should tell us is that a 6 lb L pully is NOT delivering quite 6 lbs of boost for the HD - the HD with a 6 lb L has approximately the same SC RPMs as the L with a 3 lb.

Now Tim Skelton mentions on his site that the stock SC really begins to run out of gas once it begins to be overdriven - see http://www.timskelton.com/lightning/...dyno_data.htm. So our loss isn't necessarily a bad thing because our SC is still running really close to the SC's limit. This should mean that the lbs of boost we obtain from the 6 lb pully should produce higher HP and TQ per PSI from running in the SC "sweet spot" than the rating posted for any L pully - i.e. if the L 6 lb pully is rated at 18/50 then the HD could see more. The following is more pure speculation: By looking at Tim's incremental HP info on the L and making some big assumptions about similarities to the HD, I'd guess that the 6 lb L pully will deliver closer to 20/58 on the HD due to the fact that the HP remains in the 4 HP per PSIG range.

Anyhow, that's maybe 2 HP and maybe 8 TQ over the L rating for the pully. Lots of thouhht and speculation for what amounts to nothing?

If nothing else, I am now sold that the 6 lb L pully is safe on the HD.

Anyone have a comment re my speculation, math etc before I explode my truck?

 

My thoughts are identical to yours... I posted a similar line of reasoning on the L forum here as well as on world some time ago. Basically, I agree with your assesment. That is, that we net a few more horses and torque for the first few pounds of boost becasue we are not moving into danger zone as quickly...

Unfortunately, I finally gave up discussing pulley ratios and net gains as I really couldn't find anyone with enough information for me to build a solid case with.

I am running a 6lb lower and won't be headed for an 8. My Diablo goes back and forth unitl I get a near perfect tune. Once I do, I will get a 55 shot Zex setup for my truck. That will net a helluva lot more than another 2lbs and will leave my truck a little less vulnerable during everyday driving.

As mentioned in my previous posts, I can't get to it until after the new year...

here are some of my previous discussions...

https://www.f150online.com/forums/sh...threadid=91085

https://www.f150online.com/forums/sh...threadid=91080

Ken

*edit* Nice to see someone else chasing the same thing I was...