Jon B.

If nothing else it would look pretty darn cool. Issue would be the plenum "Y" off the SC I would think.

hacker-pschorr

Why would you need two?
How much power are you trying to make? In theory two are needed for a 1,200hp car, one would be more than sufficient with a 500-600hp application in a 928.

One of the many advantages to an air / water setup is you can basically increase the size of the IC by controlling the water better.
The McLaren SLR was suffering form heat soak in extreme heat testing. Increasing the size of the IC was out of the question so the water pump was increased with a larger heat exchanger - problem solved.

Water capacity is also a big factor, a lot of factory boosted cars with air / water IC"s do not have a very large water supply. We are blessed with the 928 by having a 3+ gallon system once it's all setup using the windshield washer tank.

The layout of using two of those would be challenging. Yes the supercharger can be clocked 90 degrees or more to change the outlet direction for such a setup. IIRC from the conversations we've had about such a setup, hood clearance would be an issue.

It would be a cool setup though, IMO unnecessary unless you are going for some really big power (which is what started the conversation in the first place with Tim's car).

inactiveuser1

You're right about up to 600hp being enough for the car as they can't get traction with street tires as it is and if they did things would most likely wear or break over time if the cars hooked up with no wheel spin from a standstill.In a situation like what Carl is doing going to Bonneville with the blown stroker or some sort of extreme racing the dual setup would be something to try if someone wants to get above the normal setups up to 600hp without doing the supercharged/stroker combo.

dprantl

I've known about those PWR intercoolers for several years now. They look really neat. Not too useful on a twinscrew car though, but for a centrifugal or turbo car I was betting it would work great. From the video it looks like that's true. Good stuff.

Dan
'91 928GT S/C 475hp/460lb.ft

Mongo

Stupid question - is Tim Murphy still selling kits? I went to his website but I don't see any updates on it.

Z

I had looked into and gotten some information on the PWR intercoolers a few years ago. At that time, one that would fit there next to the engine on a 928 wasn't really big enough. Maybe they've changed since then though. You might be able to set up a configuration using one on each side of the engine, but it would probably end up getting kind of involved making it fit and look good. The only way to really know if two would be worthwhile from a performance standpoint would be to measure the temperature and pressure drops. At some point, you won't be able to lower temperature or reduce pressure drop any more no matter how much bigger the intercooler is.

From what it says on Youtube, the car in the video is making 315rwkw, which is 422rwhp. It would be interesting to have pressure and temperature data from different setups, to see how well stuff is really working, what can be improved, and if it would really be beneficial to do so.

Yes. He's in the process of finishing up the installation on one car now, and also shipping or just shipped two other kits, including a stage-3 kit for a custom wide body '92 GTS that was imported to the US from Germany. The web page hasn't been updated in a while, but the contact link should work.

hacker-pschorr

So I should add a counter that says: "Site updated" and always have the previous days date behind it?

I'm working on getting the video's off Google and up on Youtube and re-doing some in a higher definition that wasn't available when I originally made them. I was hosting some of the videos myself, but the free bandwidth on YouTube is hard to pass-up. They should be all on the site soon.

Mongo

Yes you are not doing your job.

blown 87

I mean really, what else can you do when you get done working all day, shovel snow???

victor25

Hi Guys

Thought I would drop in and stir this thread up a little

I have developed a new supercharger kit for the 928s4. I am using the rotrex supercharger with great results. Went to the dyno last night for the first time and got some very interesting results. I will post the chart and a couple pictures for you.

I started this adventure with large 100mm pulley. It is a very simple setup, super easy to install, and had great results. Now of course once you go boosted it's never enough. So I changed to a 75mm pulley, installed an fmu, and off the the dyno I went

First run was in stock configuration without the supercharger turning. I got the typical s4 results with the flappy dip and all.
Second run was with a 75mm pulley installed....Holly cow what a difference!!! So I get done with the pull, shut it down, and go look at the screen. Not what I was expecting. Great torq, but short on HP. So I asked if that looked right. He says it looks ok, but somethings is not quite right. He says lets make another run and check your air fuel ratio. Sure enough same numbers after the second run and you can see the air ratio goes lean above 4ooo rpm, the torque drops off and the hp levels off. After a short conversation where I explain the car has 19lb injectors and high fuel pressure, he says he bets we are leaving at least 50hp and 20lbs of torque on the table with those little injectors. So either the FMU was not keeping up or I need bigger injectors

So in conclusion... if anyone is interested in running a Rotrex system, and strapping on an easy 100hp and torque with 4lbs boost let me know. You pretty much get to leave everything on the car completely stock, fans, intake manifold, crank pulley, ect... Just install the bracket with supercharger, oil resevoir, and tensioner mounted on it. Replace the fuel rails and hook up an oil cooler. It takes only a couple hours. Now obviously your car has to be maintained correctly, and your knock sensors need to be in good shape. Personally I will recommend pulling your intake, clamping all the hoses, checking the sensors, changing the breather setup, and so on.

COMMENTS, QUESTIONS ????

inactiveuser1

Nice setup,I like the idea of leaving the stock fans in place.
Are you going to go with intercooler later on?
Stock chips?
Stock exhaust?

victor25

My car is completely stock, the only thing it had before installing the supercharger is an RMB. Stock exhaust, chips, ect...

I'm figuring to offer this unit in 2 steps. The first is just a basic inexpensive 4psi setup with a 100mm pulley on the charger, bracket and fuel rails. The second setup will be with a 70 mm pulley, larger injectors, and shark tuned chip. Both very simple to install and easy to upgrade from a level 1 to level 2. I can sell the level one now, but as you can see the level 2 will be a few weeks.

90 S-4

What will the boost psi be with the 75mm pulley
& why the need to change the fuel rails ?
Nice set up

SeanR

Cost projections? Fuel rails can stay stock and you can shove huge LB injectors in there.

Imo000

Do you have a run with the 4 psi/10cm pulley?