And of course, now for the numbers... The dyno day didn't go as expected, but it wasn't a problem with the supercharger... it's my warm-up/pressure regulator (WUR)... a problem I've had before but *NOW* I do have to replace it. We did get three dyno pulls in, but couldn't do any tuning of the mixture and tweaking of the advance/map curves. So how did it do "out of the box" with no tweaking? Over 250 hp at the rear wheels, which equates to over 300 hp at the crank!! The chart below shows both my best baseline from a year ago, and how it came out today. Our best guess is that we'll probably be able to get another 15-20 hp out of it by tuning the advance/map curve after I replace my Bosch WUR, since it hasn't been optimized yet at all. But I'm pretty happy even if we didn't get ANYTHING else out of it. My hope (goal?) was to get the 308 car at or slightly above the hp of a regular 348 (300 crank hp), and we've done that!! Image Unavailable, Please Login
Very nice indeed!! I am interested in the blip at the end of the graph, which looks more like a dyno artifact (believe me I've had a few). Anyway, you are clearly well into the 240s on rwhp and right at 300 crank hp out of the box which is very cool! Now for all of us geeks, do you have the A/F graph that goes with the dyno? It would be very technically interesting to see how the A/F plotted against hp. Oh yeah, what was the boost? This dyno hard documentation of a really professionally planned and executed mod is nothing short of brilliant. Congrats on a stunning success!
smg2, CONGRATS on a great design! The torque gain down in the 2k-3k range is more than I expected! BTW, That before curve is almost identical to my '82 Euro QV's dyno curve. My peak hp was 183 & 7k rpm, peak torque was 150 @ 5.7k rpm.
Graph is below... I think Scott has the system setup for 10 psi boost (or was it 12?) at redline Mike Image Unavailable, Please Login
Yes, we know that the fuel/air is going too high in that middle range... that's what we were going to tweak (among other things) until we realized we were having significant problems with the WUR/pressure regulator. I've already been talking with Larry Fletcher. What I *may* do in the meantime until the replacement arrives is to lessen the advance in that RPM range via the XDI-2 advance map functions since I'm somewhat stuck in trying to flatten that a/f ratio.
I think you will pick up a A LOT of mid range hp once the mixture is under 14 between 3.5K and 5K rpm. It stays about 14.9, so it's not too bad for cruise, but a little more lean than optimal under load and increased cylinder pressures. Still - that K-jet mechanical injection does an amazing job for what it is designed to do. Great work!
Took it out for a good drive this morning. What fun!!! I have to get used to the supercharger noise. Some may call it a "whine" but it's an additional mechanical sound that's very prevalent at idle or just off idle -- somewhat similar to what you hear from a deisel Mercedes engine though not as loud -- but is only barely there when you're driving. But the "pfft" from the blow off valve between shifts under hard accelleration is a very noticeable and cool-sounding noise that I liked right away! That blow-off valve action isn't there during shifting in less agressive/casual driving which puts you back in 'stealth' mode. I had taken the tip inserts back out of my Stebro exhaust... this thing really ROARS! I stood on the sidelines and had my mechanic drive it yesterday so I could hear it from outside as it went by... WOW. Not quite LM, but still a lot of WOW factor. As noted by Verell, the nice improvement in low-end torque is definitely there in addition to the high-end power. I can take the hills in my neighborhood at low speeds more easily than before. On the open road, there's nothing noticeable when cruising, but the power is definitely there when you punch it. I had a tiny bit of rubbing on the engine bonnet mesh from one of the clamps, which I could see where the black aluminum mesh got shiny there. I pushed it up with my thumb in that area so it is lightly indented upwards, and put a small piece of rubber on the clamp as a bumper. That seems to have solved the issue. Cosmetically, I fixed the mesh by putting a piece of copier paper under the louvers from the top, and then did a quick mist on the mesh from the bottom with black primer from a spray can (though I *could* have been more precise if I wanted to bring out my airbrush). I've had to do this before, because my stock airbox would also rub the mesh unless the box was seated absolutely as low as it could go. I *think* I may put a vacuum-boost pressure gauge on the center console in place of the clock if I can find one that looks like it belongs and works off an electronic sending unit. My problematic WUR is making hot restarts difficult, but that's not a supercharger issue. I have NO problem with the engine or oil overheating.
Using comparative Dyno-Jet dynos on the two centrifigal supercharger kits with an older 40 DCNF Weber on a 3.2 development graph as back-up, I think clearly shows once you bring your mixture richer a couple of points you will really pick up the hp in the mid range as the S/C installations are running comparable boost. Since HP is all about getting air+mixture to the engine (insert famous Mark E. biblical quote here), the fact that the 40 DCNF Webers on a stock head/cam get about as much air to the cylinder as a supercharger shows just how flow restrictive the K-Jetronic injection is. As a recommendation, it may be safe to turn up the low end boost a bit as the Webers actually make better torque (i.e. cylinder pressure) down low, but then run out of air over 6 as the head flow restriction becomes the limiting factor. Of course, the S/C can blow past the head restriction giving the last little run to the top. So, I think Mark's car will at least do at least or more what the other S/C car does once the mixture is sorted (2v vs 4v). As you can see at the end, they generate similar numbers when the mixtures are similar. It will also be interesting to see if the Webers catch back up later after the head is ported with increased airflow. Great work by everyone, I think. best rt <<Edit>> Another Dyno of the "green line" kit has just been posted ( http://ferrarichat.com/forum/showpost.php?p=136716634&postcount=271) Interesting to compare, especially the A/F; hp numbers difficult to compare as he uses DIN numbers and mph x-axis instead of RPM. Important to note his graph is in DIN hp, while these are SAE corrected. Not a huge difference, but DIN reads higher numbers than SAE. Also a great installation on Lou's part. Image Unavailable, Please Login
russ, can you overlay Lou's QV run as well, then we'd have 3 QV's modded to see what's going on. Lou will have HP left on the table due to the stock ignition, but it would be interesting to see the curve. for MikeC's ignition maps I was up till 3am the night before writing new ones, I'd tweak it between runs on the dyno. the program could be easier and is decent for the price point. the WUR acting up wasn't helping us, so it was hard to get decent comparative runs running lean. I think he has about 3 good maps, I'll also be writing him some more to try on the next dyno run when the WUR is sorted. Larry was great help that day in getting the system tweaked. so if anyone needs anything CIS related call Larry! and since this is a slipper slope with the hunt for HP I have more mods up my sleeve that will get better results out of the CIS , nope you're all going to have to wait. i have some video that'll I'll edit down and get hosted soon, I got to experience southern thunderstorms last night that shut down the Atlanta airport for 2hrs. delayed my last leg out by 3hrs so I got home early this morning. I know Mikes happy, but I think we have at least another 25hp on the table once the control pressures are fixed. Mikes dyno runs from the yr before also had a bit of lean problem which is why he's showing a low baseline for a QV. even still we picked a respectable 88 rwhp.
Guys, Kudos to a fast installation and a killer SC!! Don't take this the wrong way, but just a small aesthetics comment. Is there nothing that can be found to replace that horrible looking piece of dryer hose from the intake duct to the SC? (I know it's not dryer hose, but it looks like it.) To me at least, it cheapens the look of an otherwise first class product. Just my $.02 Birdman
Dryer hose! dryer hose! I'll have you know..... that's actually high temp brake duct hose. the hose will be retained but will barely be visible when the carbon/kevlar replaces the 'temp' layout. honestly it's the easiest way to get air flow to the supercharger where there are 'variations' between models and tolerances.
Will need to get the data with rpm on the x axis to compare. <<edit>> Based on his graph showing about 240 hp at about a stated 6000 rpm as the plugs failed, Lou's graph is probably essentially the same as the green line graph. A bit of a guess, but the one point is pretty close and it is the exact same kit as the green line. <<edit>> I think all of the owners benefit from these cross compaisons with boosted K-jet, as they can simply set their pop off valve and boost ratios to match the optimal combination found on the best car; Webers are a bit more artsy in their tuning, but the idea is the same. While the current SC's do turn more high rpm hp, the Webers are still the bang for the buck winners, especially in the daily driver torque rpm range. Will be interesting to see what the ported heads do. Ok, it looks like an expensive dryer hose... Great work, all of you!
Just for grins I changed my data from SAE to DIN in the Dynojet/WinPEP software. My 252.68 max power number went up to 256.32, which puts my computer crank hp at 313. 'Course, there was something "special" about the 308 hp for the 308 car so I guess I'll stay SAE!
Took the car out for another drive... I *think* that the supercharger unit is already getting a little bit "broken in" and less raspy, and more towards the whistle or whine that people describe. It seems a reasonable presumption that Vortech does nothing to actually break these things in, and I don't know how good the tolerancing is on the interior gearing, so it will probably continue to get "smoother" sounding as I get some more miles on it. Scott, was that your experience?
The "fast installation" thing is a BIG plus in my book. Start the supercharger install and have it street-testable the next day? Fantastic. Unlike the other system, this came with everything and we didn't have to send the old dampner off to be welded/machined. And the harmonic balancer from Nick that replaced it and aluminum custom pully from Scott is substantially lighter than the stock dampner/pully combo.
I know, I know!! That's why I said it looks like dryer hose! I don't mean to insult you, because I know it works great and the whole thing is basically an engineering masterpiece, but it just looks so........."dryer hose"! I know why you used it (because it's flexible and gets lots of air where it needs to go), but is there no better looking alternative? It looks like a dryer hose in the engine compartment!
Lou sent me the files for comparison and what I can tell you for sure is that they were in different gears for their test. I'm guessing Mike was in third and Lou was in fourth. Lou was unable to get an rpm trace due to a faulty pick-up. Check out the mixtures. Mike is the red one. Very cool installations both, and ultimately quite comparable - as you would expect from the math. Gotta run, more later.. Image Unavailable, Please Login
Question on this part: "Take off warm up regulator and reposition using new brackets" Do you still need the "warm up regulator" with this SC setup?? On the "other" SC install, i was reading the manual and they remove the regulator. They explain why you don't need it, but that part was not available to download.
might be a misprint on Carls, the WUR or warm up regulator is what controls the CIS, or more specifically it is the control pressure regulator for the CIS, without it the car will not run. I think Carls is referring to the AUX air regulator, we also removed that on Mikes car.
Wasn't sure if that's the one that some people remove cause they didn't want there engine reving that high (3k), before it warms up. Just trying to understand.
Couldnt a cockpit controllable pressure control valve replace the WUR? With a cockpit A/F gauge you could adjust it right where you want it?
