SGT/SC#0471 Posted March 3, 2008 Report Share Posted March 3, 2008 Do underdrive pulleys comprimise charging ability? And what is the hp increase by putting them on? Thanks! Link to comment Share on other sites More sharing options...
Flyingbadgers2001 Posted March 3, 2008 Report Share Posted March 3, 2008 I had one on my CS8 Mustang which I traded in on a SGT. The Steeda underdrive pulley is the one I had. Install was easy with air tools. The mod didnt have any effects on my instrumentation or my gauges. I seen dyno results that did have improved HP and torque. The numbers were like 5 hp and 7 torque. Its a simple mod that added with a pair of ceramic coated headers and a BBK 62mm throttle body could add modest HP under 870 bucks. My .02 Link to comment Share on other sites More sharing options...
JeffIsHereToo Posted March 3, 2008 Report Share Posted March 3, 2008 Do underdrive pulleys comprimise charging ability? And what is the hp increase by putting them on? Thanks! That's just how they work! If it were optimal cars would come with um! Like spoiler delete, some people swear by them, others say it's almost no difference. I did a lot of research on them and found tests where they found no real difference, to others that gave 2-5hp. Check out: http://en.wikipedia.org/wiki/Underdrive_pulleys http://www.teamscr.com/pulleys.htm The last got only 3hp with NO accessory belt! Anyway....your hp may vary! I'm leaving well enough alone. Link to comment Share on other sites More sharing options...
LuLu Posted March 3, 2008 Report Share Posted March 3, 2008 The theory behind an underdrive pulley system is to reduce power sapping drag on RPM. The goal is to allow your engine to spin up into it's power band sooner, and if this produces/translates into RWHP/RWTQ, it's because of the reduction in drag. Most folks report a favorable boost in the seat-of-the-pants dyno, and I have no doubt you'll be a tad quicker in the 1/4 mile. But, remember the magic is in reduction drag, not the creation/development of new power. With regards to their effect on charging and cooling systems, yes there may be a few adjustments to make, or, live with. But, nothing serious, it's only at idle RPM, not once the car is rolling. I've had the Steeda and March kits on 3 4.6L-4V cars, and they seemed to work for me with no complications. But, they are in conflict with a supercharging system (all of them) if you go that route down the road, so, put your stock pulleys away, don't throw them out. FYI...You can do more in this area of drag reduction on the stock engine with an electric water pump. There are a few to pick from, and they require some special attention to the electrical system to prevent failure. But, in the long run they are as reliable as the serpentine drive belt system and the manual pump. My experience with them has shown they can result in as much as 15 RWHP/10 RWTQ gains. Happy motoring, gents. Link to comment Share on other sites More sharing options...
TheKurgan Posted March 3, 2008 Report Share Posted March 3, 2008 I have the Steeda UPD and I can tell you that you will feel the difference. I haven't dyno'd with it but I know it has to be at least 7-10HP gain or I would not of felt it. You're not going to feel a 1-2 HP increase, but 10 you will. Lulu is right it reduces engine drag much like an aluminum/carbon fiber drive shaft will do on the back end(Huge reduction in weight). Less centripetal force that the engine has to disperse == less drag on the engine == more torque/HP to the rear wheels. I have not notice any effects on the charging system or anything else and I developed a habit a long time ago of paying special attention to my gauges. Ughs! mispells! Link to comment Share on other sites More sharing options...
SGT/SC#0471 Posted March 4, 2008 Author Report Share Posted March 4, 2008 Thanks guys. LULU , thanks for the s/c info, i am in the midle of expanding my business, then it is s/c city for me.....so I guess it's a moot point now. Thanks! Link to comment Share on other sites More sharing options...
JeffIsHereToo Posted March 4, 2008 Report Share Posted March 4, 2008 I have the Steeda UPD and I can tell you that you will feel the difference. I haven't dyno'd with it but I know it has to be at least 7-10HP gain or I would not of felt it. You're not going to feel a 1-2 HP increase, but 10 you will. Lulu is right it reduces engine drag much like an aluminum/carbon fiber drive shaft will do on the back end(Huge reduction in weight). Less centripetal force that the engine has to disperse == less drag on the engine == more torque/HP to the rear wheels. I have not notice any effects on the charging system or anything else and I developed a habit a long time ago of paying special attention to my gauges. Ughs! mispells! I'm still left to wonder why, and these things have been around for years, why if that al this were the case, and there was no issue using them, why does not one car ship with them from the factory? Link to comment Share on other sites More sharing options...
LuLu Posted March 4, 2008 Report Share Posted March 4, 2008 I'm still left to wonder why, and these things have been around for years, why if that al this were the case, and there was no issue using them, why does not one car ship with them from the factory? Maybe I can help? Ford engineers are more concerned with NVH issues than building power. Give them a choice between reducing NVH, or, adding 20 HP to the brake HP rating, and NVH wins every time. There are other issues, mostly back in modular history than at the present time. When UDPs began to emerge into the modular engine world, there were several suppliers and choices to make. There was also a lack of field testing prior to release. This can land you in a trouble zone if you're not careful. Some kits are designed to use the factory damper (harmonic balancer) while other replace the damper with their own design, and this is where you need to do your homework. The cast cranks on 5.4L and 4.6L modular engines are not internally balanced. Balance is achieved by the flywheel and damper working as a team outside the engine block. Flywheels on manual trannys can be heavy and they do a good job in reducing harmonic imbalance. With auto trannys, the torque converter replaces the flywheell. But, this is at the rear of the crank, what controls harmonic imbalance at the snout? The crank pulley and damper. This is critical because as engine RPM increase and power builds, the crank will telegraph vibration in both directions. The oil pump is also crank snout mounted (just inside the front cover) and the drive gears are made of the same powdered metal as the connecting rods. Powdered metal construction is a double edged sword. Like MDF in construction applications, stronger and lighter than other materials. But, hit it wrong way, and you have a handful of sawdust. Excessive vibration through the crank snout will destroy the oil pump and along with that, the rest of your engine. Imbalance is at it's worst at high RPM, not the time to lose an oil pump. BTW, if you're building a custom engine, the cast crank can be polished and internally balanced with heavy metal. But, if you are not, an external bolt-on is your only choice. Over the years, Ford engineers worked to reduce crank vibration and crank dampners grew larger and heavier. It's been a while since I've counted them, but my last count was seven revisions from 1998 through 2004. The lighest and smallest weighed in at 5.5 pounds, and the last I had in hand weighed in at 9.9 pounds. I don't know the specs on our 3V SGT dampers, but I'd bet it's been revised once again, considering the power available from a stock 3V engine. Thus, you need to make your choice carefully, and IMHO, retain the OEM damper. Some aftermarket products can be expensive, such as the Romac. It's NHRA-SFI certification puts it close to 400.00, and if you're not building an engine and racing every weekend, this is excessive. I'm not trying to dash anyone's hopes here. It's not a bad mod for a few extra ponies and some low end grunt. Just make an informed decision? Happy motoring, gents. Link to comment Share on other sites More sharing options...
TheKurgan Posted March 4, 2008 Report Share Posted March 4, 2008 Steeda's reputation is the reason I chose them over the others. Also, this statement on their website: "Our underdrive pulleys are the only pulleys engineered through our unique partnership in Ford's technology transfer program to have the proper torsional vibration dampening characteristics for your 4.6L engine. No other manufacturer can make this claim." http://www.steeda.com/products/s197_underdrive_pulley.php They also list other ISO standards, etc which reassured my confidence and this pulley is well tested by now. Lulu quit scarin' people Link to comment Share on other sites More sharing options...
willyumm930 Posted March 4, 2008 Report Share Posted March 4, 2008 "...look at the big brain on Brad". Seriously 07SGT4729, that's a ton of good information. Thanks! Link to comment Share on other sites More sharing options...
JeffIsHereToo Posted March 4, 2008 Report Share Posted March 4, 2008 Thanks 07SGT4729! While I understood only about every three words... it's good info! -jeff Link to comment Share on other sites More sharing options...
LuLu Posted March 4, 2008 Report Share Posted March 4, 2008 Lulu quit scarin' people I assure you, sir, not my intent. I identified it as historical data, a little background from a few years back. Someone taught me what I know, don't feel right keeping it to myself. Happy motoring, gents. Link to comment Share on other sites More sharing options...
rpretzel Posted March 4, 2008 Report Share Posted March 4, 2008 "...look at the big brain on Brad". Seriously 07SGT4729, that's a ton of good information. Thanks! Good to see another Pulp Fiction fan on the site. I'm sorry. Did I break your concentration? Link to comment Share on other sites More sharing options...
mywickedshelby Posted March 4, 2008 Report Share Posted March 4, 2008 "...look at the big brain on Brad". Seriously 07SGT4729, that's a ton of good information. Thanks! I love that movie. Samuel was the best. "That would have to be one charmin' MFin pig" Link to comment Share on other sites More sharing options...
351PONY Posted March 4, 2008 Report Share Posted March 4, 2008 I have the Roush under drive pulley system on mine and have had zero issues from it. It does seem to allow the engine to reach peak RPM's much faster then it did previously. Hope this helps. Link to comment Share on other sites More sharing options...
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