Gretch

First phase is the fueling modifications, injectors, FMU, fuel pressure gage. Murphy's manual is quite detailed. However there are subtle differences between each years builds, so I am editing the manual as I go.

This car has 97k miles on it and the engine bay is in remarkable shape. There is not a of of room but by taking my time about things I find it pretty reasonabe working conditions. A magnet on a stick is an important tool for working around this intake manifold......don't ask.

I did find something interesting, In assembly at the factory (because the engine has never been apart since then), an inch long loop of the wire harness leading to the second injector in, on the drivers side, was pinched between the head and the cam cover. And it was squashed about as flat as it could be. I loosened the cam cover bolts and got it out. I am surprised it never shorted out after 15 years and 97,000 miles.

BTW, it was -18 in the mountains Saturday morning.

Rez

I hope we can rely on detailed steps of your mods.

Good luck!

Gretch

Well, I purchased Tim Murphys kit, so the devil (or at least, Tim) is in the details.

Pretty standard stuff though. Rising rate fuel regulator, Vortech SC trim blower, water-to-air-intercooler. New injectors, Boost , fuel pressure and AFM gauges. The real magic of this kit is in the specific engineering Tim has done on some major parts like the pulley design and the bracket and tensioner, as well as making a COMPLETE kit, including a full color installation manual. As I progress through the project, I will update on anything interesting I found. I am taking lots of pictures, and editing the manual for 89 GT specific stuff, as I go. Tim has been good to deal with and very enthusiastic about the project Now that the Packers are out of it he and his gang can get back to work on some of the new things he is developing.

I have a shop that will do the Dyno in the spring.

Drewster67

A Video Documentary would be cool. Good Luck with the Install and BTW - It was in the mid 70's today - Golf anyone?.

Gregg K

The White Mountains of New Hampshire.
I can't drive my car the way I want to. But I'm guessing that the White Mountains of New Hampshire are just about perfect for a 928. Am I wrong?

Lagavulin

Hey Gretch, I'm excited for ya!

When you dyno it in the spring, I'm looking forward to seeing how much more horsepower you'll get with the GT cams versus our S4 cams.

By the way, did you do a NA baseline dyno?

Gretch

Gregg, the mountains are why Gretch is semi-retired to my farm in New Hampshire. I wanted to retire to my home in the mountains when I hit 50, but alas, The market didn't co-operate, so Gretch retired without me. I commute to Beantown during the week and go home on weekends. Driving the 928 through the canyons, (we call then "Notches" up here) is a great way to enjoy the RMB and all other attributes of the best hot rod on the planet.

Lag, well, you were my inspiration, as a matter of fact I have about 6 different pictures of your engine bay on my computer to remind me to pay attention to appearances as I install the SC.

I did not do a base dyno, so I am not giving Tim the benefit of the doubt there, I am going to assume the 330 BHP (w/rmb) of the GT and factor a 17.3% loss to the rear wheels. Then do the math in reverse for the Dyno results. Does that sound fair?

Lagavulin

That's definitely fair, but the main reason for the baseline dyno is to get a pulse on the health of the engine before the supercharger is installed. Therefore, if the numbers happen to be low, one would know right away that something is not quite right, and remedial action can be taken if deemed necessary as the supercharged output directly corresponds with the engine's NA output, for better or worse.

Did you perform a compression and leak-down test?

Gretch

Lag, I never had a reason to do either of these tests. The engine has always run very strong (in fact I had second thoughts about the SC last summer, 'cause this thing is such an animal in its NA form).

The more scientific side of me would have done all three tests you suggest, before starting the install, but I just was not up to it before I put her away for the winter this year.

I am looking forward to the Dyno results in the spring, and if there seems something not quite right, I will deal with it then. Tim promised me 8 pounds of boost and xxx hp based on a healthy 89 GT engine. That is all I am expecting.

Gretch is semi-retired from being a daily driver (C4 took over that duty) and only sees about 2 or 3 thousand miles a year now. The SC install is for show, and some very brief "go", basically for bragging rights and wow factor from the other Porsche heads in the local area here.

This car has been good to me all these years, as a show of appreciation I spend a lot of money and quality time wrenching on it now. It is just a hobby.

On the weekends in the late spring, summer and early fall, me and the wife go for "spirited" rides in the mountains, and for one week a year I bring it to the city and drive it to work. That is all the duty this car sees any more. Hell I spend more time wrenching and waxing on it then I do driving it. It may well be my favorite toy.

Seth W

Gretch:

Can't wait to hear the results and how the install goes. Are you using an intercooler for 8PSI?? If so, where are you mounting it? You are the 89GT test case. While I'm not so sure I would SC my car as I someday hope a 993TT is next big thing, there are times when I doubt I will have the $ for such an investment and could much more justify holding onto my 928 and making it a TT competitor. GOOD LUCK!

Lagavulin

Since you drive it, you should know it's relative health and it certainly sounds like she's good to go.

If you think Gretch goes now, you're not even going to believe it once the supercharger is installed! By the way, a GT should get around 450 rwhp at 8 psi.

Oh, one more thing. I have a sneaky feeling that once the car is supercharged, you will be driving it much more than you do now, and Gretch will be diggin' it; it's just too much fun!

Gretch

Seth W, Yes, Tim's kit comes with a water-to-air intercooler, a pump setup and a radiator. The intercooler fits in the back top of the engine bay on the passenger side. I cannot give any more details as I promised Tim I would keep his engineering secrets, However this aspect of the SC solution is very well engineered.

BTW, I found out something else very interesting about our cars while talking to Tim about fuel plumbing. The fuel supply line is routed through a section of the AC cooling lines to chill the fuel, just before it is fed into the fuel regulator. Man, if I had known that I would have used my air conditioning more often........

I know I am a test case for the 89 GT. Some here think I should be burned at the stake for such heresy........I can appreciate that position and plead "No Lo" to it.

sweanders

Does anyone have pictures of the Tim Murphy kit, I'm dieing to see some...

Gretch

hear, try this. This is a picture of Tim's kit in Lags car. I know it has been posted before, so I am on safe ground.

Lagavulin

Here's another one, there's no more orange stuff now: