Hi Everyone,
Good Lord… eight pages already?
GR8 ASP, yep, sorry about that, I was thinking volumetric efficiency but my fingers were typing adiabatic. Suffice it to say I’ve been pretty busy lately and I *wish* I had a little more time to focus on things outside what I must do right now.
Ok, first, the graph and asking about how I plan to handle the temperature increase shown in that test at Autorotor. That test was running 1.6 bar, or about 8.8 psi. 8 psi is about the magic number where anything above it really could use cooling, be it from an intercooler or water methanol injection. I could go into details about the tests I did, building an intercooled version of the Gen2 kit and testing temperatures, but the bottom line, water cooled it more efficiently, so we went with that for those who wanted to maximize the ignition timing. On the Gen3 kit, and honestly, the way the Gen1 2 kit was built, 5 psi is the target. It was only after people had 5 that they wanted more. 5 does not heat it as much (obviously…lol). One thing I didn’t like about intercoolers, their inherent restriction and having to drive the supercharger harder to overcome it and get the same boost on the cool side.
Ok, on the Gen 3 kit. Take Bob’s comments, factor in anything you ever felt was a negative about the Gen1 2 kit, then address them. That’s what I did going into the Gen3. I really had to take some time to sort things. Unfortunately, it took a while for some technologies to become available so the solution would become what I needed it to be (practical). Four months ago, you couldn’t use a 2 bar MAP sensor on a stock PCM with SCT flash programmer to tune an engine. Now you can. I feel pretty good about how they’ve done on the trucks the last few months. Imagine, no VEC and wiring…. J I also needed a larger displacement low profile Supercharger. That Gen3 engine is really efficient, especially in the mid range. That, along with a small diameter crank pulley required a larger displacement compressor. Well, that’s now available too. Cylinder air equality and making the HP as high as the torque, solved that about 2 years ago and integrated that into the Ram SRT-10 kits. A stock Ram SRT-10 (manual trans) through all stock everything else, including cats, runs 575 RWHP and 575RWTQ at 6psi (straight axle, heavier and taller tires, different gear, so it’s not a direct comparison to a Viper).
The last little hurdle was that close hood to engine clearance. I ran several different designs in the past and am coming back into one of those now for the “low” version that fits under the stock hood. The “tall boy” version will be at VOI with the ’08 hood.
Anyway, I’ve been working on this, on and off, getting a divorce and going through everything else (say, building 300 car and truck superchargers) for about four years. I stopped stressing and worrying about this kit a couple years ago when I saw that it was just going to take time to get the things I wanted to build it right. That’s what I’ve been working on and that’s why it took so long. Sorry, but that’s just the way it went. I probably should have never said “yes, I plan to build one” so I didn’t disappoint anyone with my time frame. However, after making all those Gen1 and 2 kits, everyone just expected it and we all have that “want it now” mentality when it comes to our toys.
So, I’m getting things ready for VOI. I think it will be a good place to have the debut. J
Sorry if this post seemed to jump around a bit. As usual, I’m in a hurry. It’s 8pm and I really need to get out of the shop. 13 hours is enough for today.
Regards,
Sean
PS, At some point I can talk more about why we use a positive displacement SC. It's pretty basic really, you don't have to spin the motor higher RPM to make the power and you certainly don't have to drive around at full throttle beating up on it at low RPM either. I like the low RPM because of the bearing speed these engines have with those 3" mains, no cam bearings, two piece valves, low valve spring pressure, etc. That all just screams "keep me under 5,200 RPM if you want me to live forever".
Oh, last thing, peak HP on the Gen 1 and 2 SC kits, that will go up when I get around to making a replacement manifold on that kit so they have better and even air flow. Will probably integrate an SCT into it too (say bye to the VEC, though it still is good for what it can do). But don't ask me when that will be. I have my hands full right now and we're probably going to move the shop in three months too. I lost the lease on the test track and there's just no reason to have this big building anymore.
even with the extra weight.
Also, any plans on putting a larger blower in the GENII?
