underdrive pullys

[BakerEdition]

Whats the scoop guys?

 

[toms89]

They reduce the parasistic drag on the motor by spinning all of the accessories slower. But there is always a compromise. The factory sets up the system to hold up to worse case scenarios. Towing in 100 degree heat for instance with your a/c on max so there is some room to play. Consider that your fan, water pump, alternator, a/c will be spinning slower. If you have a high electrical load or live in a hot climate I would be concerned. The problem is the expys primarily live at very low rpms to begin with and this is where underdrive pulleys will have issues if any.

I have done underdrive pulleys on my mustang and the charging would drop noticably at idle. Also cooling was compromised. Different vehicle though. I would not do it with my expy as I dont want any potential issues with any of these systems. Just my opinion..

 

[GAINMOB]

good to know...i put it on my to do list...more research needed...

 

[panda24619]

same. it was never on my HAD TO DO list. but its on there.

 

[Thermo]

Like Tom says, the underdrive pulleys reduce the speed of the various components. If you have a fairly stock Expy and live in the northern climates, PROBABLY won't be a problem. But, how many people drive something that will PROBABLY get them to where they are after? you get down south and in the heat, you can anticipate having more issues as now you are battling both heat and electrical demands. Keep in mind in our X's, you are going to be pulling potentially 60 amps just to run the A/C system. At idle, the stock setup can barely handle this. You spin the alternator slower and you will be running off of the battery for part of your electrical loads. Now you add in less cooling water flowing through the engine and I'm sure you can see where they will be bad on the engine itself.

If you are thinking "what if I put a smaller pulley on the alternator to make it spin faster?" Then why have the under drive pulleys in the first place. The load on the power steering pump is very minimal. Ok, maybe you save 1 hp (at best) with the power steering pump running slower. But, for the cost and effort, is it worth it?

Underdrive pulleys have their spots. For the most part, they should be used on racing vehicles where the RPMs are kept up high. IN that application, they work great. Otherwise, keep the truck as is.

 

[GAINMOB]

got it...cause i live in VA...summers are high 90's/100's...them i'm moving to FLA in 6-7yrs...

 

[BakerEdition]

Thanks guys....as usual all great input....cant say it enough...GREAT FORUM!

 

[walnuts4x4]

yeah never something I thought was worth the money...

 

[TheGuyWho]

THERMO pretty much summed it up, so I dont need to say much. But my opinion is: Not worth it! Dont do it!! The power gains are so minimal its not even worth the time! Ive heard of these UDP's causing all kinds of problems. Too many of my mustang buds have done UDP's and have had issues.

 

[BakerEdition]

Sounds good....dont need more headaches...Im married got enough already...

 

[LameSuburbanDad]

I have a set on my 99 E.B. I love them, I notice no changes in any of gauges, none of my lights flicker and my windows don't roll up/down any differently.
as for the power increase...about 10 Hp, a little less in torque, and pretty much Zero in MPG.

but like I have said before, If you do the pulleys, with the Gotts mod, with E-fans, and with air intake and MAF sensor, you DO notice a hell of a big change.

I don't know about anyone elses truck but mine is a bad **** now. I rarely lose a stop light drag, I cruise at 18 mpg highway. I get 500 miles out of a tank of gas, and it just has power for days through all the RPM bands. I have pulled semi trucks uphill in snow, and I have driven 7 hours strait in 85-90 degree heat on the Hway fully loaded, pulling a trailer with two ATV's a stove and a fridge.....NO PROBLEMO. if you can find a set for cheap enough, hop all over it. just my opinion, that's why we're here.

as for the parasitic drag removal, all that has been said is spot on, the kit changes the three pulleys right in the center of the engine, a smaller alt pulley, a HUGE idle pulley, an a slighty smaller crank pulley, remove the clutch fan and go E-fans, you can see how the power gains would quickly stack up.

someone please let me know if these numbers are off and I will delete them
Programmer = 30 h.p.
pulleys = 10 h.p.
fans = 10 h.p.
intake, MAF, and spacer combo = 3 h.p.
Gott's mod = 1-2 h.p.
cat-back = 8 h.p.

your talking about almost 60 H.p. total. with the money you spend for such a relatively small increase in power for such a large heave truck, the only place you really notice the gains is, well, everywhere. I can get onto the highway with ease. I spend less money in gas. I love it, I notice the change, I'm the only one it matters to, I am super happy I did it. and can't wait to add more.

 

[SOLISIMO]

THERMO pretty much summed it up, so I dont need to say much. But my opinion is: Not worth it! Dont do it!! The power gains are so minimal its not even worth the time! Ive heard of these UDP's causing all kinds of problems. Too many of my mustang buds have done UDP's and have had issues.

You read my mind. Ive heard horror stories from the mustang guys too.

 

[toms89]

"Programmer = 30 h.p.
pulleys = 10 h.p.
fans = 10 h.p.
intake, MAF, and spacer combo = 3 h.p.
Gott's mod = 1-2 h.p.
cat-back = 8 h.p.

your talking about almost 60 H.p. total"

Many of these are advertised hp gains and or guesstimates.

I think you would find that if you strapped it on a dyno it is far less than that. The advertised figures are generally optimistic and what they don't tell you is it is the peak gain over stock on the graph or through the rpm range. This is not across the board or rpm gains. While it would be nice....the hp gain figures just do not add up like that its the system as a whole. It is not cumulative.

I have tested my mustang with various bolt ons and the manufacturer claims. The truth is the average hp gain through the rpm range is far less than the claims and they do not add up as such when added together.

 

[2000eb]

i wish i had access to a dyno fo free haha cause i would love to see what i have done to the expy so far and see about future mods

 

[TheGuyWho]

someone please let me know if these numbers are off and I will delete them
Programmer = 30 h.p.
pulleys = 10 h.p.
fans = 10 h.p.
intake, MAF, and spacer combo = 3 h.p.
Gott's mod = 1-2 h.p.
cat-back = 8 h.p.

your talking about almost 60 H.p. total.

NO WAY!! Not even close… I would be extremely impressed if you even got 20 HP gain with all that on these trucks. HELL, the mustang boys cant even gain that much HP with the exact same mods, or very similar mods. But like Toms89 said, these are "advertised" gains, which in layman's terms means over inflated, "they wish," horse power gains. Hahaha In fact what you are actually feeling is not a HP "gain" its a freeing up of existing restricted factory HP. Example, if you take the manufacturers advertised HP rating when you buy the car/truck and immediately take it to get dyno'd it WILL NOT make that advertised HP number, wont even come close. Now granted a lot of these HP ratings at the crank or flywheel, but the fact of the matter is everything is overrated, including the stuff you put on your car.

 

[panda24619]

yeah i hate factory hp ratings. cause its all at the flywheel. they take an engine to an engine dyno and dyno it. do it till they get the best number. print the receipt. change a few things then say its that. kinda bs. and as for the gains i would be shocked if i got 60hp out of everything. i would be shocked if i got 10mpg out of my edge. i call bs on that. cause i switched everything to stock before i put my edge in and had to drive around a bit before since it still picked up the hypertech. then i put the edge in. its improvements are mainly at the top end. i do agree though that all those improvements will increase your hp. but maybe by like 30 at the top.