John..

It is qualified to be called a "Bastard"

jheis

As I recall, the Ford 4.6L is pretty much a copy of the 928 engine.

If you've ever seen a cut-away drawing of a C-5 Corvette next to a cut-away of the 20 year earlier 928 chassis - its not too hard to see where that design came from (with the exception of the transverse leaf springs).

So, if you put a Ford 4.6 in a C-5 Corvette is it a 928?

James

pcarfan944

I saw that car at lake Calhoun all the time this summer. During the Wheels of Italy car show in August, he parked the 928 right next to the show parking lot to try and get some attention, no one was interested. That about says it all.

Parnelli Joneser

I stayed away from this thread for days thinking it would be a bash fest but have been surprised by the generally acceptant tone of the posts.
My thoughts are-
The qualites that make a 928 a 928 lie more outside the hood than under it. It would be a shame to sacrifice a decent car for the lack of resources needed to keep a Porsche engine in it. I'm thinking most Chev transplants didn't start out as Plan A for the owner-

"Dude, you bought a Porsh!"

"Yup, and my cousin's on his way over right now with his cherry picker so we's can yank this double cammed overhead motor whatsit and slap that 400 out of my old Blazer in it! It's gonna rock!"

"Yeah, didn't you put like 5-6 hundred in that motor before you rolled the Blazer up elk huntin' last year? Good idea, but there's no way your 400 is gonna fit in the back of that thing, man."

An unlikely scenerio(but alas, not impossible). More likely it's the best compromise that allows the car to be used as it should be. And as a life long Ford man it pains me to make this observation- small block for small block- the Chev is more cost effective than a Ford on a $$ to HP basis, plus they're standardized as THE transplant motor regardless of application. Just paint it black and keep the hood closed and drive, drive, drive, I say.
The Mad Max blower-out-the- hood look? Uhhhhh, perhaps a tad over the top.
That said, it'd be a cold day before you see me dropping a Chev motor in my 928. But that's just me.

I can't believe no one has came up with this yet- A Chev powered Porsche- a 9-Z28!?!

Malibu310

The essence of a Porsche is its strength, smoothness, and handling... none of which was effected by our conversion to the Chevy engine. However, what was affected alot was the dismal tourque from a stop that the original 1982 928 delivered compared to 550 pounds of torque at the get-go. The reason for building the car was it made far more sense to build a Hot Rod 928 than a late 60's Muscle car, as the basic 928 frame can actually handle the kind of power that a Chevy Blower motor can deliver.

In the end the car was built for show, but we have discovered that the other qualities of the 928 were not affected, other than not being able to see where your going on a right turn with the blower. This was a father - son project that we discovered is a blast to drive! The engine WITH THE BLOWER still weighs LESS than the original 928! Pictures can be seen at www.rhsdplanning.com/porsche.htm

I have purchased another 928 which will be the opposite build with stealth as its goal. The 1987 Black 928 will have a 430HP 430 Lbs Torque Chevy 383 stroker motor with 18" Wheels (done) and be very quiet. The interior wil be upgraded with light woods and a modern GPS-Stereo install like the latest luxury cars.

If Porsche delivered 928's with the explosive torque that an American engine delivers, they might still be in production. Supercharging a 928 engine is not an option because of the costs - benefit... The custom engine is being built as I write this, and after I'm done I'll have a 928 with all of the modern conveniences expected of a car built today, be reliable, and have enough power to at least keep up with a C6 Corvette... all for about $20,000. As far as our Hot Rod, our $25,000 investement is quicker than most anything around on one or two wheels. Imagine having two cars and still be less cost than a new Vette?

Parnelli Joneser

Don't take my previous post as anything other than a fleeting stab at humor...looks like a well crafted conversion by Malibu~310. Having done a small-block into a 240Z myself, I have no problems whatsoever with conversions of any sort really.

G Man

I would love to have a V-8 Z car. Almost went that route before I got my 928. There is a huge amount of info at www.hybridz.org about z-car conversions.

H2

I would have nothing against a chevy powered 928 IF it were built right...that is, strong, not cobbled together, all the original gages work, etc., etc. I think one would have to be built by a good mechanic in other to do these things, however. I'd expect there's no way are you'd be able to get the Porsche brains to work with a Chevy motor....so, unless well done top to bottom, you'd really only have a streetrod with lots of aftermarket gauges and levers, etc. Sounds like some have done it successfully though. The yellow one with the blower is impressive. I'd opt for one with all the engine below the hood since I'm into the daily driver thing.

I've heard that the Renegade adaptation kit is not as well engineered as it should be and you have to make your own adaptations to make it work right. Is this true or just Porschevy bashing?

Yes, I'd buy one if I knew it were built by a capable and precision-conscious mechanic. Does anyone know of a honest-to-goodness well engineered Porschevy daily driver for sale?

Also, being a street rod, does the insurance rates increase?

Harvey

Parnelli Joneser

The Z car conversion I(we) did was done employing the outline from JTR (Jaguars That Run), an outfit in California, IIRC
The small-block into Z is a win-win, more power/torque and the engine weighs a bit less(if you use an alum. intake, etc.) AND that mass moves rearward in the car and down. The JTR method places the entire engine behind the centerline of the front axles. I divested myself of it before completion, but I still have the book...
What's the weight difference between a 928 lump and a small-block? I have my M28/12 "spare" engine cunningly disguised as a rolling work bench, but it sure seems damn heavy for an all-alloy unit. And bulkier too with the OHC's

Old & New

Malibu,

Nice job on the hot rod. Questions, though... why do you say the car was built for show "in the end"? It sounds like you are saying that you intended on building a car to drive and enjoy, but ended up with a car which looked great, but was impractical for some reason... I'm not sure I agree with your use of the term "investment". It sounds more like an expense, unless you intend on getting more than $25K back on it somehow.

Why do you think supercharging a 928 is not a worthy cost-benefit? It's getting quite popular around here for just that very reason. For less than $20K, you can have a supercharged 928 which dyno's at 470 HP/440 Tq (C6 looks a little anemic at 345/345) ...on the road in two days. How much labor do you expect to "invest" in your next project?

Another nice cost-benefit of supercharging is that the car retains its market value; the components can easily be removed from the vehicle to restore it to stock trim.

rob rossitto

as a kid, I put a built 289 into a pinto...was a hoot, but corners were an issue as the car was at 85/15 and the rear was a bit skittish as a result(ok it was nuts)....

guess the idea of ruining a concour quality pinto wasn't much of a concern for me - but I can't leave anything alone so I guess purist OEM stuff just isn't my bag... ie, there's "always room for improvement", although the pinto had a bit more room for improvement than a p-car, of course

old habits die hard - my 928 stroker thing is hardly a p-car motor anymore - moldex crank, msds headers, je pistons, nicom, devek radiator, etc...not much left OEM except the valve covers, block (sort of) and intake... it's got more american stuff under the hood than german, (and don't forget the suspension/brake/stereo/etc upgrades) so does that mean it's not a pcar anymore?

my guess is that a purist would have a heart attack, but as long as it rocks I'm happy... in fact, to take it to the "next level", a different block or blower is really what's needed - either way it's far beyond OEM at that point....

IMO, as far as the hot rod world is concerned, it's still a pcar - just a pcar w/a bigger attitude (but the hood scoop thing is a bit much, IMO) the purist gang will of course gag, but it won't last long since they'll quickly disappear from your rear view mirror....

regards!

Malibu310

The blower sticking out of the hood makes for a show car instead of a street car, as rain and in this area snow would make this type of blower motor impractical. The visibility problem further complicates "daily driving". Otherwise we could consider it for a daily driver, that is if we could actually live with 8 miles to the gallon! My SLK 32 has a blower that is only used on demand, something also impractical with a GMC 6-71 Blower (Mad Max was fake). There would have been other stealth blower options.

OK, as far as an investment, I''ll bet that if we listed on E-Bay, we would get better than our money into the project, but we did not build it to sell it. It's about as practical of transportation as my Buell, but like the bike, its a blast to drive. As far as reliability, every component on that engine is specific to a blower motor, and we should enjoy many years of trouble free driving.

Supercharging a 928 Engine? I seriously doubt that taking a stock 928 engine an adding any type of blower will result in a reliable platform. If we blow up our chevy, it's a few thousand to fix... a 928 would be a tremendous expense, that is if the rest of the engine is not modified. To build a proper 928 blower motor would be very expensive, far more than the Chevy. We are building a daily driver 928. Cheney Performance is now shooting for 500 lbs of low end torque, which will be verified on the dyno this friday or next monday. The non-supercharged engine built with the best parts will be under $5,000. The installation will be about $2,500 and the Renegade Kit cost me $2,300. The Kit alone to supercharge a 928 without installation is $7,600. What I get is a blueprinted state-of-art zero time engine instead of upgrading my 97,000 mile engine... In a few weeks I'll be able to see what kind of gas mileage the car has... hopefully it's not too bad.

Anyone want to buy a Mercedes SLK 32 (AMG) cheap?

Old & New

Hey, different strokes for different folks. Time will certainly reveal the reliability level of our supercharged engines. There are at least a couple dozen (?) out there & the number is steadily growing since the advent of a few good vendors here on the list.

My comments regarding the sale of 928 conversions are based upon the few we have seen pop up on eBay, which generate very little bidder interest.

Say, you got any plans for that 97,000 mile engine? It's barely broken in.

Rob M Budd

I put an LT1 Chevy engine in my 80 928 3 years ago. I used a some of the Renegade kit and fabricated a few other parts. It took about $7,000 and 3 months of weekends and some evenings. The original engine ran fine but was seriously weak by today's standards and leaked about 2 quarts of oil every 500 miles. It sat in storage for 5 years before I bought it.
It took many hours pouring over Chevy LT1, Corvette and Porsche manuals and I spent a lot of time on details.
After 3 years of spirited driving I decided on a new interior and paint. Now I have an excellent, fast and reliable daily driver. While I'm happy with the performance, my only regrets are that it wasn't an S4 with the suspension upgrades and I didn't modify the Chevy LT1 to more than 368 HP. For another 1-2K I could have added about 50-75 HP.

As far as the brains and electronics, I was surprised how the two different systems merged together. The 928 injection system is separate from the rest of the electronics. After disconnecting the wire from the injectors, fuel pump, throttle body, temp & oil sensors, etc, and following the wires you'll find they go to the brain and then to one connector on the board below the fuse panel.
Disconnect that connector and the whole harness and brain come out.
The LT1 brain goes in its place. All one needs to do is replace the ends in the connector with the ones for the LT1 and plug it back in. Since your now using the LT1 harness, all the injector and sensor connections for the LT1 are right there and plug right in to the various places on the engine.
With a slight bracket modification, the brain can use the same bolt holes in the right front passenger well.
The oil and temp sending units also hook right up to the 928 gauges without modification along with the tach. The gauges, warning lights and central warning system (!) works just as before for low oil pressure or high temp along with the usual chassis warnings.
I installed a single bulb check engine light for the LT1 which works just like any later model check engine light.
The Delco AC compressor and power steering pump are within the operating range of the Porsche system, so all that was needed were some custom made hoses. Same with the heater hoses and fuel lines
The AC control uses the same wiring so no mods beyond wire connectors required there. The heat and AC work just like before.
The LT1 throttle body has provisions for the 3 cables. The main accelerator cable was replaced with a stock Camaro cable with the Porsche clip on the pedal end. The kick down cable needed a GM end on the throttle body side.
The cruise control cable also needs a GM end.
It uses dual Spal 11" electric fans triggered by an additional temp sensor/switch on the LT1.
I've installed a Delco 140 amp alternator with can handle everything including the upgraded sound system. The starter and charging system wiring is the same for the Chevy and Porsche.
With an adaptor from Renegade, the torque tube bolts directly to the Chevy bellhousing.
There was no cutting or welding to the 928. It was entirely bolted in. Should it be desirable to go back to a stock 928 engine it would be feasible.

One feature of the LT1 is the programmable chip. Several programs are available to log performance and engine functions, i.e. rpm, spark advance, fuel ratio, engine temp, intake air temp, o2 milivolts, injector pulse width, throttle position, speed, idle air control, etc. You can log track runs or regular driving for extended periods and save them on a laptop. The cable interface uses a standard serial port.
Once the data is logged you can view the graphs and charts and then make changes in the program and transfer the new program directly to the chip with any Windows based system. For example, you can change the fuel ratio and spark advance all through the RPM range or just certain ranges, either advanced or retarded. Or trim the fuel of each individual cylinder. There is no need to buy additional chips and you can reprogram it within a few minutes.

Normy

Now I'm a bit of a purist. I don't have any problems with chevy/other engine conversions, but I'd just ask the questions: 1. What happened to the M28, and 2. What is going to happen to the M28?

There's nothing at all wrong with a 928 powered by a foreign engine...unless it's owner thinks there is. Personally, I'd consider a foreign engine conversion while I rebuilt the original engine in the garage.

N!