Originally Posted by tmmii

Originally Posted by Young Performance

OK. I was trying to avoid typing a dissertation on how a supercharger works and why. I have done literally hundreds of engines with Whipples, so I'm confident of my suggestions on which blower you should use. Now I'll explain why.
Overkill in most aspects of engine building are a good thing. However, that's not necessarily true when dealing with a Whipple. Notice I didn't say supercharging. Overkill is fine with a roots blower.....spin it slow, don't build a ton of heat, blah blah blah. Not so with a Whipple. They want to spin. We regularly spin them up to 18000 rpm, or more. They don't like to spin slowly. If there is 1 downfall to a Whipple, it is that they have a tendency to pitch the air and fuel to one side at low rpm when the blower is spun to slowly. We've been able to mask some of it with Distributorless Ignition, but it's still present. In extreme cases, you can have 3.5-4 point AFR point differential from 1 bank to the other. The DIS is hot enough to burn most of the excess fuel that is pitched to that side. Other then that, there is nothing you can do. One side is on the verge of fouling the plugs and the other is super lean. Now, as soon as you start making some rpm, those issues go away. But, how much idling do you do? I'm sure a lot like everyone else, you do quite a bit.
Each of Whipple's blower setups have a window where they should be ran. You wouldn't use a 4L quadrotor to make 900 hp. Can it do it.....sure. But you won't be happy with the result. Just because it can do it doesn't mean it's right. I had 1 particular customer that bought a 2.3L quadrotor setup without consulting me. We were originally building around 900 hp. i told him that there was no way I could do that with that blower on 600 ci. He didn't want more then that because the boat had Bravo's. I put it on the dyno and made 1175 without even trying. He said "too much". I started taking boost out. I got it down to 1000 hp and it was TERRIBLE. Ended up at a little under 1100 hp. Once in the boat and idling, 1 side had AFR;s in the low 10's and the other in the high 13's. It was starting to put soot on the transom behind that one pipe on each engine. If I went any leaner, the engine would stumble going in gear. After a year of using it, we installed DIS. It was WAY better, but far from perfect. We still had at least 2 points from bank to bank at idle. Adding boost would have fixed it but he didn't want the added power. The correct supercharger would have prevented any of this from happening. You WILL run into the same issues with an 8.3L Whipple on a 600 ci engine making 1200 hp. Now, if you want to make 1300++, then that would be a good choice. Actually, the 5L would have been a good choice as well but they have discontinued it. It's the same blower as the 8.3, but spins the opposite rotor. Regardless, it's not available anymore.
They started building the larger single blowers to take the place of the quads. The single 4 and 4.5L were designed to replace the 2.3L quadrotor. They are much more compact, cheaper and easier to maintain. The 3.3L was easily replace by the 5L and 8.3L but is still available. I used to use the 2.3L quads pretty often. They were fantastic and made excellent power. We've made well over 1400 hp with them. However, once the 5L came out, we never used another 2.3L quad. The 5L was cheaper and MUCH easier and cheaper to maintain. They made more power then the 2.3 quad as well. The quads look extremely cool. I'll give them that. But now, the only quad I'll use is the 4L quad when I want to make stupid power. That's what we used on the engine that I posted above on youtube. That engine made almost 1800 hp when we spun it up. That pull was only to 7100 rpm and it made 1726 hp. We turn it well over 7500.

Now on to the intercooler. They are no different then the superchargers. Overkill is not a great thing. The FOAC is sooo efficient that it could cause issues. If you cool the intake charge too much, you can actually bring the fuel out of suspension. Liquid fuel doesn't burn. You must keep it atomized. If you live in northern climates, you will definitely have an issue in spring when the water is cold. Again, these aren't like your typical aluminum intercoolers. The CuNi that they are made off is one of the best suitable metals for heat transfer. They are certainly capable of pulling the IAT well below ambient air temp. There is no need for a FOAC on anything under 1500 hp. The MOAC is more then sufficient for what you want.

I've already said it twice, but I'll say it 1 more time. The 4L will easily make over 1200 hp on a 600 ci engine. It can make upward of 1300 hp if you really spin it. Not the ideal situation though. The 4.5L is the perfect fit if you want no less then 1200 hp, but the ability to make quite a bit more. With enough head and cam, you could make well over 1300 hp. Either of these would be great with the MOAC intercooler.

Hopefully this answers all of your questions. Take it for what it's worth but these recommendations came from many years of building engines and using Whipples. We use them on probably 95% of our SC engine builds so we are very familiar of their capabilities and their drawbacks. A lot of this I had to learn the hard way but you, and everyone else that takes the time to read it, gets it for free.
Eddie

Originally Posted by getrdunn