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MrShift@EdmundsMrShift@Edmunds Posts: 43,693
edited March 21 in Pontiac
This topic is for those of us with big ideas but temporarily small budgets.

We aren't exactly dreaming in this topic but the projects we are describing here might take 6 months or a year to see the light of day.

I'll start with the next post.


  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    I have an older Porsche 928, a 16 valve V-8. It's pretty fast and an excellent handler but by today's standards it could use more HP.

    Given that these Porsche V-8s have indestructible bottom ends and a nice roomy "V" between the "stand up" cylinder heads, as well as good space fore of the engine, I'm thinking that a Supercharger running about 6 psi would be perfect for this car.

    With any luck, the installation you see below should produce about 330 HP and plenty of low end grunt.


    Cost? I'm estimating about $7,500, including a professional install.
  • driftracerdriftracer Posts: 2,692
    I've ALWAYS been a fan of 928s.

    Of course, I'd take the Texas approach and do a stroker Chevy small block (over 400 ci, probably 406), with aluminum heads and Accel DFI. And a nasty, lumpy cam and Flowmasters, so folks would know there was something strangely wicked hiding under the bonnet.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    Nah, I need something that I can drive everyday. And besides, you can build these motors to put out as much power as a Chevy and still have the compact size for a nice clean and attractive fit.
  • driftracerdriftracer Posts: 2,692
    a car with a Chevy small block every day?
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    Because as you spec'd it, it would be an animal to drive and would sound like a pile of bowling balls in a clothes dryer :P I want a very docile and tractible engine...which is why I like can crawl or you can wail.

    But no need for a Chevy...I have the car set up with a Y-pipe back of the header and a free-flow Ansa sounds GREAT, and with the whine of a supercharger, it would be dee-vine. Sounds very much like an American car right now but the firing pulses are just a little different than an American V8...and it revs faster and higher than say a stock pushrod engine.

    Some nut actually build the 928 engine up to 600 HP but I don't expect it is very tractable either.

    I'm really aiming for a very versatile car and decent fuel mileage.

    Also we have to think about the drivetrain...this has the engine in front, transmission and differential as a single unit in the rear...I don't think a big brute Chevy would hook up to the Porsche 5 speed, so we got big conversion problems here...

    Basically to run a Chevy I think you'd have to gut a complete C5 Corvette, which has a very similar driveline and rear suspension (GM, have you been peeking under 928s?)
  • How do the CARB boys like that set-up, Shifty? Your local smog shop is gonna see all those hoses and send you on your way.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    It'll pass smog or I won't do it. Might have to go to a special referee. That's part of the delay.
  • I think the only way you'll get by a referee is if you have a CARB expemption for the system. Being that the market for superchargers on 928s has to be pretty darn small, I'd suspect who ever developed the system didn't spend the many thousands of dollars it takes to get a CARB exemption.
    Your best bet may be to bring to some little smog shop that has never seen the engine bay of a 928 and hope they think that that is the way it's supposed to look. I'd go for black tubing connectors though, the blue ones really scream aftermarket. I have them on my car and that';s the only thing the guy challenged me on last time I had to go to a "Test Only" center. I managed to convince him that the piping was all stock (which was true) and that I replaced the cracked rubber factory hoses with blue silicone, which should be legal. After that it was just a matter of passing the sniffer test, which my car did easily.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    Yep, I need a strategy that's for sure. I could also go across the border to Nevada--which one clever Edmunds community member suggested should have the license plate slogan "Nevada----yeah, you can do that here"
  • driftracerdriftracer Posts: 2,692
    is SO cool - my Ion Redline has a custom fabbed cold air system and a custom fabbed exhaust - when you get on it, the Eaton WAILS and turns heads - you can really hear it scream with the intake opened up. Way too much fun for a 41 year old guy...
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    I checked it out...I think as long as it passes smog out the tailpipe, everyone's cool with it. Question is, how do you know it's going to pass out the tailpipe until you build it? Probably if I don't mess with the injectors and have the catalytic hooked up I'll be fine.

    Next question is, do I spend $7,500 for a hotrod older 928, on a car I know is good, or sell it for $6,000 and add another $7,500 and buy a later model and faster stock 928? The newer 928s are not supercharged, but are 32V motors. Faster but way more complex as well. Damned if you do, damned if you don't, sounds like.
  • Legally, they are supposed to fail you for any aftermarket mods that don't have an expemption number, regardless of what the sniffer says but many shops aren't too diligent about that. That's why I suggested getting black hoses if possible. Anything that peaks a shop curiosity is bad.
    You can ask for a pretest to check your emissions before doing the real run. I always do that with my MR2. Once I avoided having a "Gross Polluter" classification hung on my car by doing that. Once you have a GP label on the record, you have to go to the referee station to get it off. Downside is you'll have to pay for two tests each time.
  • BTW, a wise man I know who has been around the car industry for decades has often advised people considering modifying their car that if you want a faster car, buy a faster car.

    And I misread your earlier question. You wanted to know how you would know before you decided to pursue this whether it would pass the sniffer.
    You'll probably have to rely on the outfit that makes that kit for their experience. I don't know enough about how 928s handle fueling and ignition at WOT, open loop conditions vs. partial throttle, closed loop conditions and how the system you are looking at affects that but generally, the smog test is run at light load, partial throttle, closed loop conditions so the engine essentially self tunes and the cat cleans up any off nominal output. I'd guess the sniffer test won't be a problem.
  • Stever@EdmundsStever@Edmunds YooperlandPosts: 39,041
    if you want a faster car, buy a faster car

    That makes a lot of sense to me, unless you really want to enjoy the hobby aspect of modding your ride. Gets expensive either way (hobbies seem to do that).

    Btw, the title requirement is geared to forum improvements in the pipeline - we can't seem to stop modding around here either (and our speed has greatly improved just in the last six months!)

    Steve, Host
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    Well in general your remarks are all well taken but when you are dealing with very complex and exotic types of car, the situation changes a bit. Sometimes it is better to deal with a known entity. Fer instance, I know my car has a rebuilt 5-speed, new clutch, new synchros, new CV joints, new diff bearings, etc. Also I have an engine that burns no oil and has outstanding compression.

    Now to sell that off and get "new 928 Mystery Car X" for double what my car is worth---well, a used 928 is not a car you want to have to rebuild. Also the newer 928s go to an interference-fit engine (which mine doesn't have) and higher compression. So then I'd have to run premium fuel and sweat a broken timing belt or change it out every 30K, which is expensive.

    So there are plusses and minuses here. If I keep the old car, I save $250 a year on gas and maybe $600 a year on maintenance (easy).

    As for performance, a newer 928 puts out 326HP and my car stock is I believe 231. So presuming a 35% increase in HP with this blower, I might hit around 310HP without much stress on the engine.

    On the downside, I have the dreaded twin clutch disk, which grips like crazy but doesn't release quickly, making shifts a bit slow and clunky. But then I'm not drag racing.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    This company sells a conversion kit to install a Corvette or Camaro LT-1 engine in my Porsche 928!

    Looks like by the time you buy everything you need it's about the same price down the road.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    Yeah but I need the conversion kit at $1,400, the clutch kit and options at another $1,400, a junkyard Lt-1 and all the accessories bolted to it for $2,500, then I need an aftermarket wiring harness to hook up the fuel injection and ECU, and then I need 30-40 hours labor.

    And then I have a Porsche with a 350 Chevy in it rather than a supercharged stock motor that's all neat and tidy and costs the same.

    If I SC the stock motor, I'll have more HP than a N/A stock LT-1 motor.

    But of course, one can punch out the LT-1 motor to correct that for not a lot of money.
  • driftracerdriftracer Posts: 2,692
    potential in an LT-1 - 383 stroker, induction, cam, heads, etc...
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,693
    yes but then I have an animal car again which I don't want.

    I want a sleeper. I want to leave a $60K sportscar in the dust like you see in the viewing screen on the starship Enterprise when they punch the warp button.

    Oh, decisions, decisions...

    right now it's tax time, and I'm watching my supercharger dissolve before my least temporarily.

    My friend Monty (you know, the one who blew up two C5 motors?) has a Porsche 914 with Corvette power. It's freaky-fast. He needed to flare it out all over to get a fit.
This discussion has been closed.