Coolest (unique) DDM mod ever!

[bun1t]

Originally Posted by Craig Lewis I never really understood why this was an issue? You could argue that most other forms of boost run out of efficiency at thier top end and thus churning tons of heat into the system. For that, they achieve good low end. A centifugal blower has a slow peak, admited. But when it's out of it's efficience range, the result is not heat. Less heat in the overall package goes a long way. It's rather a matter of compromise with your intended project or specific use. Most of the applications that suit centri blowers are on NA applications where thier relative compression makes up for a slow bottom end of a typical centri blower. Thier advantage with heat can typically be taken advantage of with tuning and there is no questioin that heat plays a big role in sustained power and reliability. The 2.4 solstice's extra displacement, compared to the LNF, will further enhance it's low end and maybe make for a well balanced combo. Anyway, I'm surely lonely with my opinion. I thought Mallet's curve looked pretty good. I look forward to seeing the results.

The power under the curve with a centri s/c is lacking and you have to rev the piss out of your engine before you start making any real power. Although it's typically easier to intercool than a roots s/c. They both have their pros and cons but I'm not really a fan of s/c'd 4 cylinders anyways.

[Craig Lewis]

Originally Posted by bun1t The power under the curve with a centri s/c is lacking and you have to rev the piss out of your engine before you start making any real power. Although it's typically easier to intercool than a roots s/c. They both have their pros and cons but I'm not really a fan of s/c'd 4 cylinders anyways.

Surely my previous point had some merrit.

[scdyne]

I guess only a dyno will tell us one way or another weather a centrifugal S/C will be worth the effort?

[Chemist]

Remember, some folks are the sole repository of knowledge and wisdom. The rest of us are just along for the ride.

[duckSol]

Originally Posted by Chemist Remember, some folks are the sole repository of knowledge and wisdom. The rest of us are just along for the ride.

Here's to anuuder skewl yeer

[Dave@ddmworks]

Well here is what some of you were waiting for, a couple dyno runs and some interesting observations on the centrifugal setup.

The centrifugal setup put out 244whp and 220ft/lbs of torque at 7.5psi.

So for those that are following along at home, that is only 1.5-2 psi more than our stage 1 supercharger, but almost 50whp more. Also we ran some tests on it and it reaches the same top speed on our test circuit as Randy's car did with the Stage 2 setup, which offers similar horsepower at the wheels.

So does this mean that we are switching from the Positive Displacement blowers we use in our kits now? Well the short answer is no.

I have attached the dyno of the Centrifugal setup and the one comparing our PD blower setup to it.

If you look at the graphs you will see that they both do make the same peak horsepower, but the PD blowers have a lot more low and mid range, which makes for a more streetable daily driver. Also this was very noticable up at Deals Gap when we were testing the car up there. The car lacked the power getting off of the turns that we were used to with Randy's Stage 2 setup and definitely with the Stage 3 setup. So does this mean the centrifugal is worthless? short answer is no.

The centrifugal does a really good job at moving some air, and considering we are comparing a system at 7.5 psi to a system that is at 9-10 psi and they are making the same peak power, it is doing pretty good. Unfortunately, we are pushing the unit we have here as much as it will go and can not pulley it to push some more air to get it to the same pressure, but at 10 psi, upper 200's at the wheels would be possible. Also the other thing to keep in mind is that these core supercharger units are more expensive than the units we use on the supercharger kits we sell now, so there would be a price difference. Also if you look at peak torque numbers the positive displacement supercharger has the edge there.

So in the end is one better than the other? the short answer is no again here. They both offer a unique driving experience, the positive displacement supercharger feels like a much bigger engine. The centrifugal is very linear in its power delivery and is deceptively quick, but never really feels like it.

So for someone looking for a unique quick setup, this could be the answer for you. We initially took on this project out of curiosity more than anything else, however after testing we are going to produce a kit like this for the 2.4L using the rotrex. So if you have a 2.4L and are looking for some extra power with a smooth delivery, let us know we want to work with you!



Comparison between the Centrifugal and the Stage 2 supercharger

[Kappster]

Dave,
From your previous post I would surmise that the centrifugal set up takes alot less power from the engine to make the same pressures. (50 horse more to the wheels for 1 to 11/2 lbs of pressure) over your stage one kit. So this would mean better fuel economy less loading of the crank and linear power to the crank allowing higher peak horses with out yanking out the drive-train. (longer overall drive-train life). Maybe not the bottom end, but you test was running a 71/2 lbs boost. What about 10lbs?, 12lbs?
When will we see this set up and how much will it cost? Your the man to do this!
This company is already doing it for the miata and hondas with great results. KraftWerks: Home Good read!

[Kappster]

I want my MTV.... I mean Rotrex!

[scdyne]

oh.. someone actually understands the theoretical value of a centrifugal S/C.
I have been tied up with Halloween displays lately and haven't had time to update my progress on the kit. Needless to say I haven't had time to do much, but I'll have an update later this week or early next week.
I actually may still take it to Kraftwerks before the end of the year for some dyno fun. I have friends there that have been asking about it also. Rotrex has exclusive license limitations on who can sell what systems and KraftWerks is limited to Imports only.

[Kappster]

This would appear to be the most efficient system out there so far. So where is the system?
Is there any interest in this type of system?
Engine life, Higher H/P with less pressure. A quieter system.

[hammy221]

for me i love to noise and the instant power of the MP62 kits and well engine life if your worried about hurting your stock engine build it... i do got to say look around on the net there are huge numbers coming out of the LE5 stock internals as for me i got to build min i want more power and more power....... HA i think iam going MADDDDDDD I TELL YA!!!!