From: Marc Reviel [marc@powerlogix.com] Sent: Friday, September 13, 2002 3:14 AM To: 928 Subject: [928] Lies, damn lies, and 928 superchargers (Or a FAST missive) Well, I guess it's time to answer many questions put forth recently about FAST products. MISSION STATEMENT Most importantly, please recognize our goal with developing these supercharger kits - to produce a reasonably priced, serious power option for Porsche 928 owners. We love the 928, and in addition to being 'power-junkies,' we were growing more and more worried about the fact that some SUV's can out accelerate it! In fact it seems just about every car produced now is very powerful. We want the power level of 928 commensurate with the car's original impact, and uniqueness. We did NOT want to make into a 1/4 mile drag car. We wanted to keep the upgrade as low-cost as possible, retain daily-driveable docility, yet still be able to raise the driver's (and passenger's) adrenalin level with a tap on the throttle. Although it may not sound like it, we are actually quite conservative when it comes to design and engineering. We have to be. The top people in our field follow this in all their developments, such as Mark Anderson/928 Int'l and Marc Thomas/DEVEK. Marc Thomas has said it time and time again: "Design verification" is everything. This is job 1. Even ONE customer who has a failure with our (or their) products due to a design flaw is totally unacceptable. 5 PSI For many reasons, we chose 5 psi nominal boost level. 5 psi may not sound like much. But that number is deceiving. A supercharger adding 5 psi to an already superbly designed ~5L engine has dramatic results (see our website for dynos), while keeping complexity, cost and at absolute minimum. (It needs to be noted that many of our customers have gone way beyond this with great success, even though this was quite outside our original performance and testing envelopes.) 5 psi results in around 45-50% more torque! And 40% more hp! We use only one supercharger vendor: Vortech. We wont go into why Vortech is the best, but suffice it to say, we've seen all the rest and they are mostly problematic junk. Vortech is worth every penny. FUEL-MANAGEMENT To again keep costs low, we decided we must use the stock fuel-management system. And, moreover, there is no reason not to. Every 928 since 1984 had mass-flow. Mass-flow systems have the inate ability to fully compensate for temperature and air-density changes. Porsche (and Bosch) was kind enough to design in plenty of headroom for this to work perfectly at 5 psi of boost. We supply the parts and knowledge necessary to make it all work seemlessly. We also have very specific tuning procedures that, ensure the entire system is reliable and SAFE. Prior to our kit, every earlier "one-off" supercharger attempt resulted in damaged engines. We had never heard of a single success that stood the test of time. And, of course, the rumors flew - we heard it was the rings...or the ring lands...or the head-gaskets...etc, etc. We never got any concrete information on the individual systems, or the definite failure-mode(s), or any real engineering data, for that matter. However, it was our opinion at that time in the mid-90's that no one with the proper qualifications and engineering knowledge had worked on these attempts. We decided it was time to put put a full engineering effort into it to find out what the real issues were. After all our development, it was clear what had happened: Detonation. Detonation brought on by ignorance, ineptitude, misapplication, and stupidity. The most important thing we'd like everyone to realize, even after you have long since forgotten this post and FAST, is that - with all else being equal - at low-boost levels, the ONLY failure 928 engines are prone to is *detonation.* That is to say, if the fuel-management side is modified correctly, and tuned correctly, 5 psi of boost will not impact the reliability and longevity of a street-driven 928 engine in any way. CONTINUOUS INJECTION SYSTEM There has been talk of supercharging the earlier cars with CIS. There are some reports of one or two successful installations out there that are blowing through the CIS metering plate. If it is functional to some degree, this is a laudable accomplishment. However, we still maintain with great steadfastness that CIS systems when blown through - without any other fuel correction - is, at best, a hack. CIS was a really neat system in it's day, and we have tuned innumerable CIS 928's on the dyno. We know these systems inside and out. The problem is there is NO way a CIS system can compensate for air-density changes. This is *exactly* what a supercharger does: increase air-density (pressure) in the manifold. The mixture setting is a gross-offset adjustment - that is, it moves the transfer curve up and down. If you simply "crank" it up to where you have enough enrichment to handle the highest boost level at the highest RPM, you are also running grossly rich at every point below that max. boost setting. Yes, it might "work", but not without many very bad side-effects. Such as significant torque/power loss at lower RPMs/lower boost levels, fouling of plugs, washing away the oil film protecting the rings/cylinders, carbon build-up on valves and pistons, poor fuel economy, damage to catalytic converter (probably irrelevant), contaminating the oil much faster, smoke from exhaust, etc. Note that all the Porsche Turbos used a CIS system from 1975 until 1994. But they were all a *draw-through* CIS system. This means the metering plate sees the same density of air at all times, thus accurately metering fuel-flow. This is the correct way to do it. Again these are the results of years of tuning CIS systems. There are right ways to do things and there are wrong ways. And if we can be proven incorrect, we'll admit it! But until then, we'd like to see the dynocharts for any blow-through, virgin CIS system with the A/F ratio charted (standard DynoJet). IOW, prove it. ;) (Sneak preview: FAST will be announcing the availability of a properly designed supercharger system for CIS cars in the next 6 months.) INTERCOOLERS At 5-6 psi, there is absolutely no need for an intercooler. The added cost does not justify itself. Yes, if the intention is to run 9-10+ psi, the threshold is crossed - there are serious benefits (even necessities) for intercooling. Again, we are talking BANG-FOR-THE-BUCK here. 5 psi does not need intercooling. An intercooler will add any where from $1500 for home-made to $3000+ for custom designed and installed versions. Some will argue: "Hey if you cool the intake charge, you get more power and reliability." Yes, that's true - for higher boost levels. This effect approaches zero for low-boost levels. Again, this is also why 5 psi was chosen. PERFORMANCE Look at our dynocharts. No peakiness. That's one of the side-effects of supercharging - it tends to smooth out peaks and valleys in the torque curve. That smoothness is also an indication of spot-on tuning with the factory fuel-management system achieved when using our techniques. Side-note: the S3 and S4 intakes have the same performance achievement with supercharging. After the installation and tuning, you end up with a clean-running 400+hp engine with a broad torque curve, and 100% reliability. It feels just like a factory would have done it. The 928 is back on top! Other Power Adders The only other refined upgrade to date has been strokers (+ opt. boring). This is a great way to go. The only issue is the financial barrier (and down-time) to get there. The FAST s/c kit is something that the owner can install in one weekend with standard tools - it's a bolt-on. Again, bang-for-the-buck. (Of course the utimate is to combine a stroker + supercharger but that is beyond the scope of this missive.) Then there is always nitrous. It's not that we hate "the bottle," it's just that it's so unrefined, inelegant, and limited. How often do you want to go fill your bottle each month? And where do you want to put the obnoxious thing? Nitrous has it's place (I guess), just not in our 928's. CONCLUSION (finally!) We applaud those out there doing there own thing. More power to you! But for those who want a tested, tried and true, bolt-on upgrade, that can be done in a long weekend, and will not break your bank (~$5 - $5.5K), this is for you. We've put the R&D time in, and done the countless hours of testing. As of this date, we have 23 customers out there racking up mile after mile. Probably more than 300K miles in total. Some are daily-drivers, some are out at the Porsche DE events with modified versions at 10+psi! Out of all these stock installations, not a single damaged engine. This is the result of 'doing it right.' It still never ceases to thrill us to hear the excitement of a customer calling us from his cel-phone on his first maiden-voyage out. FUTURE We have more development going on; more products coming in the next 6-12 months. We will announce more when we are ready. (No other comment until then.) Stay tuned. Also, we are seeking more qualified resellers/installers interested in our products. Email us. For more questions/inquiries email Mark Robinson, robinson@powerlogix.com Thanks for your time. Marc J. Reviel Co-owner Forced-Air Systems of Texas (FAST) http://www-f-a-s-tonline.com Director of Engineering/CTO PowerLogix, Inc http://www.powerlogix.com From: Randy Page [mailto:randy.page@terraverge.com] Sent: Wednesday, September 18, 2002 11:33 PM To: 928 Subject: [928] Supercharged 87 Auto....Really Long Hi All, With all this talk about superchargers, and all the questions I have been getting off-list, I thought I would chime in and give everyone an update on what my experiences have been to date. Sorry it's so long, but hopefully this will help those of you who are considering adding a supercharger to your 928. The Car: 87 S4 Auto - 53K miles at the time of the install, and 65K miles now. Supercharger: Vortech S-trim Intercooler: Custom Vortech Air/Water (supplied by Projekt928) Installation Kit (pulleys, brackets, etc.) supplied by FAAST Installer - Me (which is where most of my problems came from!) Preparation As has been pointed out, you need to make sure the car is in good shape before installing the blower. I took my time and went through all the major maintenance items I could get to without pulling the engine. This included a complete t-belt service, plugs, plug wires, rotors, caps, coils, knock sensors, and a whole bunch of gaskets. I also took the opportunity to have a bunch of parts powdercoated. I also performed a few mandatory upgrades at this time including: low-profile cooling fans, RRFPR, 30 PSI injectors, Vortech Fuel Management Unit (FMU), and routing an oil feed line for the blower. Installation In principal, the installation should be simple. But in practice, it wasn't (at least not for me and most of the folks I know who have done this.) There are a ton of little details to work out, odd little parts to find, and the inevitable gotchas (which seem to be different for everyone.) There were a couple of months where the UPS/FEDEX guys were making nearly daily deliveries to me from the big three, Jegs, Summit, and yes...JC Whitney. But, I had never done anything remotely this involved to a car, and was breaking some new ground as one of FAAST's first customers. Luckily I hooked up with Tim Murphy and Marcus Hutchinson, who were about at the same stage as I was. So between them, the guys at FAAST (very helpful), and Eric Munck (very helpful) we were able to work through most of the kinks. First Few Months During the first few months of getting the car running again, it spent at least half it's time in my garage getting the kinks worked out. I had problems with belt slippage, poor idle, boost leaks, etc. Most of these problems were worked out with fairly simple solutions....just had to figure out what those solutions were. The Last 10K Miles Since the initial install, I have had the blower out of the car at least 6 or 8 times to make changes to the setup, change pulleys, etc. I have switched to a belt tensioner setup designed by Tim Murphy, swapped out the blower pulley a few times, and sent the blower back to Vortech to have the oil seal replaced (totally my fault.) I have also spent a good bit of time changing the intercooler setup, making the intake setup air-tight, running a cold air intake to under the headlight, installing additional fans, etc. Auto Transmission Allot of folks are asking about how the auto transmission is handling things. So far it's great, and doesn't seem to mind the extra power. With boost in the intake, it shifts much firmer at WOT, and will spin the tires when shifting from first to second gear. Fuel System I also get allot of questions about the fuel system. I think I was one of the lucky ones in that everything seemed to work well right from the start. I am running about 54PSI pressure with 30PSI injectors. The LH Brain seems to be taking care of the air/fuel ratio for regular driving. When under boost, the FMU restricts the flow of fuel back to the tank, and really bumps up the pressure. So, I use the FMU and RRFPR to tune the air/fuel ratio for WOT. This setup is working great for me with no other changes. But, I do think a piggyback controller like a Dastek or Perfect Power would be a nice addition. Result While I haven't had the car on a dyno in over a year, my guess is I am putting down somewhere between 370 and 390 HP to the wheels (with about 7 psi boost.) Back when I was at the dyno a year or so ago, I was getting about 350HP. This was with a slipping blower belt (getting a bit more than 5psi), boost leak, improperly setup intercooler (had a poor water supply), and an air filter pulling hot air from behind the radiator. For the most part these issues have been fixed, and I'm looking forward to hitting the dyno again soon. As for drivability, I would never know the blower was there unless I get on it. It's fairly quite, hasn't made a big impact on gas mileage...if I drive like a sane man, and has over 10K miles on the setup. I never hesitate to drive it out-of-town. Summary First off, I have tended to focus on the difficulties I encountered as that is what most people ask me about. Don't let that scare you off, but do keep it in mind as it can be a bumpy road. Since I started my project, there are ALLOT more folks out there who have done this, and most of the issues you will face have been solved by someone else, so your road will likely be much easier. Many of the things that gave me fits back then, I now look at and think what an idiot I was for not figuring that out earlier. Would I do it again...heck yes! After driving this car for 10K miles with the blower, I can't imagine owning a 928 and not installing a supercharger. ONCE YOU GO BLOWN...YOU NEVER GO BACK! Randy 87 S4 Auto Black/Black Supercharged & Intercooled Powered by JC Whitney, Home Depot, Ace Hardware......