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FROM 2013:The current cost for a stage-1 supercharger kit for your '85 is $5,395 + actual shipping cost (ships in one box, approximately 2.5' x 2.5' x 3' tall and weighing around 70lbs)
The stage-1 kit includes:
Vortech V3-Si polished supercharger with self contained oiling system.
Air filter assembly
All required air ducting, connecting pieces, and clamps
Vortech Maxflow racing blow-off valve
Custom Murf 928 supercharger bracket with integral belt tensioner (powdercoated satin black)
Custom Murf 928 pulleys (CNC machined and hard coat anodized)
Drive belts
4 pancake fans (mounting brackets included)
42lb/hr fuel injectors
Custom mass air meter recalibration device
Custom Murf 928 aluminum mass air meter adaptor
Custom Murf 928 Stage-1 computer ignition timing chip
Custom Murf 928 Stage-1 computer fuel chip
Replacement radiator hose
Everything else required for a complete installation
Complete installation instructions and support
For anyone trying to decide between the stage-1 and stage-3 kits, for whatever reasons, something that's an option is to go with a stage-1 kit, and then later upgrade to stage-3. The stage-1 kit can easily be upgraded to stage-3 later on. The stage-3 is really more like an addition to the stage-1 rather than a complete replacement of it. You don't end up with a stage-1 kit that you paid for and then don't have any use for after upgrading to the stage-3 configuration. The cost for a stage-1 kit and then later on upgrading to a stage-3 configuration is a little more than if a stage-3 had been purchased initially though.
One of the things that people often ask about is about how hard it is to install the kits, and whether a typical do-it-yourselfer can do it. The answer is definitely yes. We have installed a few for people, and some customers have had a shop or mechanic of their choice do their installations, but most of the kits sold have been installed by the cars owners themselves. Many of those people said that they'd never really done any very involved work on their car before. The installation ends up being enjoyable for them and giving them a feeling of accomplishment and confidence in working on their own car after they've finished. Many of them also learn a good bit about their car in the process as well.
The kit really isn't very difficult to install, and it can be done in steps that will allow the car to be driveable in between. That way the car can still be driven if you don't have the time to do the whole installation all at one time. You can do part of the installation in one day, or over a weekend, and then still be able to drive the car until the next time that you get a chance to work on the rest of the installation again. If you do end up having any questions, there's help available, so you don't have to worry that you'll be left to try and figure things out on your own.
With a couple of people working on it, the stage-3 kit has been installed in one day, but that is not typical. Most people take their time doing it, and end up looking at and cleaning things as they go. The stage-1 installation is quicker and easier to install.
Attached are dyno charts from an '86 with an automatic transmission, showing stock, stage-1, and stage-3 installations. The same car was used for all three configurations. The car was all stock except for the addition of the stage-1, and then later the stage-3 kits, and an "X" pipe in the exhaust for all runs.
The "X" pipe is a good compliment to the supercharger installation, but the Porken chips that you have now will definitely need to be replaced with the chips that are supplied with the supercharger kit.
In case you haven't already seen them, here are links to a couple of forum threads on the car that the dyno results are from:
We no longer offer the stage-2 kits, only the stage-1 and the stage-3.
The cost to upgrade from a stage-1 to a stage-3 on your '85 model year car would be $3,300. If the no longer needed stage-1 parts from the upgrade are returned in good condition, $150 is refunded to customer.
The parts for upgrading from the stage-1 to the stage-3 are an air/water intercooler system, including intercooler, pump, heat exchanger, and all required hose and fittings, all parts required for going to the dual air filter assembly, and a different supercharger pulley.
The biggest part of the upgrade cost comes from the custom made air/water intercooler. It's expensive to have them made, but they fit and work very well. That's why the competition has tried to buy them from us for use on their supercharger systems.
Love my supercharged s4, but it gets hot.
not sure what to do.
Fans seem to work correctly, but it struggles when the Temps get about 70 and I'm not roaring down the road.
Attached pictures for inspection.
Sam
Are both the pusher and puller fans working? Make sure they're spinning in the proper directions for airflow from the front to the rear. At what engine temp are they coming on and what controls them - is the temp they come on adjustable? If you can make them come on earlier you can prevent heat soak that's harder to recover from
For starters the kit came with four puller fans to go on the radiator. Also make sure they are flowing the correct direction. Don't trust your hand, use a piece of tissue paper.
My Murf Stage III 928 also runs hot. It settles around the 3/4 mark on the gauge in normal operation. Occasionally in the Florida summer with the AC running it will edge into the red band but once it gets decent airflow it comes back a little. When I first bought the car I was very alarmed at the temp but the folks here on the forum say it’s okay. Since they’ve seen pretty much every 928 scenario I trust them. I run distilled water and Water Wetter since I never see freezing temperatures, it seems to help somewhat.
I drive the car pretty conservatively but it’s nice to know the power’s there for that occasional unlucky BMW driver. 😉
Don't trust the temp gauge, let's put some real measured numbers in this discussions.
Pick up an infrared temp gun, a cheep one works just fine, they just don't have the higher range of the more expensive one's like a Fluke, then measure at the thermostat housing.
Also good to note what the temp is going into and out of the radiator
Note: An S4's temp gauge typical sits around 3/4 and that is normal operation.
I have the Stage 3 kit and I've always had an issue with the high temps also. All 5 fans run properly so I'm thinking that its the overall design of the system. Where the supercharger and airbox are placed behind the radiator I believe that it reduces the airflow through the rad and the hot air gets trapped. I haven't calculated the size of the charger and airbox but I would think it covers approx. 20% of the surface area of the rad.
That's just my observation so I've just learned to live with it. Since the fans are constantly running while driving hard, particularly in the summer, I upgraded to a high output alternator which I think helps a bit to keep up with the power draw.
My 89GT ran hot too. Definitely confirm the fans (all 5, you are missing 2) are all running the correct direction. Make absolutely sure your radiator cap is good and you have no small leaks. These reservoirs often crack.
I also removed the intercooler heat exchanger from in front of the AC condenser and plumbed in a new one under the radiator. It was a bit of project and a tight fit. Seemed to help some. I'm convinced the puller fans need some shrouds. I think they could be fabricated out of sheet aluminum fairly simply.
I also put in a high output alternator to support the fan loads (plus all the stereo equipment). I also considered aftermarket oil coolers to get the oil heat load out of the coolant radiator.
Has the radiator ever been pulled and thoroughly flushed? I've done this on a few 928's, one very low miles, and they all had a surprisingly amount of crap that came out after multiple back and forth flushing's.
Tim designed a fan shroud that drops in without any other modifications which greatly increases the efficiency of the 4 rear fans. I'm not sure how many he made, I'll see if I can dig up some of those.
Good discussion.
Certainly it is a struggle to keep a charged 928 cool, and it’s inevitable if you are not moving.
Hell, I think a NA 928 doesn’t cool well in stop and go.
To quantify some temps, 3/4 on the cluster temp gauge is 184F in the upper radiator hose with my aftermarket temp sensor, so that’s from block, pre radiator.
That’s what I see at the track, I have to confess I use the heater for cooling as well because of the supercharger(s).
Its not for everyone
Yes aftermarket higher output alternator as well.
02-09-2022, 05:45 PM
