Another Small Block Conversion Argument

[rich]

So your copying a Lexus? Why not just buy a Lexus. And there is no way your going to convince me you have 50/50 in that car. Put it on the scales before you get too far along there.... I think you would have to stick that Toyotee engine sideways under the dash and then maybe you would be 50/50.

And the Weissach is designed to change the scrub radius of the rear tires when the car is pushed through a hard corner improving traction, handling . The G load works the suspension. I have every reason to believe the ZX copy failed because it was a poor copy on a cheap car that would flex before it could deliver enough G force for a Weissach copy to work properly. The patented design improved the 928 and it can't be disconnected as you put it. It's a built in design.

I'm all about the custom stuff. I think the Alien and our 59 Bugeye are proof of that. But I have always thought there has to be a real improvement in performance and handling or whats the point?

[Plexus928]

Since I saw my first 928 back in the '70's I loved the shape, still do, the SC430 shape does nothing for me, but the engine does.
Lets not forget that the 928 was designed nealy 40 years ago,and engineering design has moved on just a tad since then, it was and is still a great car, BUT....it was never the ultimate pinacle of mechanical engineering, things really have got better in 40 years. I realise that by using a shock horror ,Japanese engine I would upset the "can't change the Porsche design club"
Sorry for dropping into your place of worship and taking a leak in the font.
No need to weigh it now, I will finish it and fine tune it ,and liKe all my previous conversions it will be set up to perform better than it did when it left the factory.
In the eyes of some I am destroying a classic, there is probably 50,000 of them still out there, they are not rare.
The body will stay fairly well unchanged, may need a bulge or scoop as a small piece of the front of the engine can be seen on an eyeball across the guards, the curve of the hood may just be enough to clear but won't know till it's fitted.
The goal is to get rid of as much of the 1970's stuff as possible.brakes uprated to match the higher output.
Yep it's right hand drive, It's in Australia, California smog test? the state that I am in is tough, but it will pass.It has to meet the emissions of the 2002 engine, (if I moved to the next state it would only have to meet the emission standard from 1982, the year the car was built.)
The pedantic wail of "must have 50/50 weight distribution" do you realise that there is 170 lbs of weight coming and going at all times right over the diff? Petrol,
also take into account the grotesque size/weight of a lot of humans these days since fast food became the staple diet, makes the 50/50 a bit difficult to achieve most times, but mine dry will be close.

Why am I doing it? I'n past 60, It's someting to keep me busy, and I quite enjoy upsetting the concours crazies.
Apart from a bit of machining,All worK done by me,transplant and getting it engineering approval to road register will be under $10,000. a cheap price for a '70's classic shape with truely modern mechanicals.
The result, faster lighter and much cheaper to maintain.

[Danglerb]

PSO Porsche Shaped Object.

Engine swaps are smog legal in Calif. The inspection is very detailed and requires 100% of smog related stuff from a newer model year Calif legal car. Sometimes the details are sticky with issues like the automatic transmission on a Corvette considered "part of the emissions system". Last I checked Renegade wanted no part of being in the middle of getting anything passed, but claimed people have been successful.

Cheaper to maintain is a dream that actual ownership will quickly wake you up from.

Some racers pin the Weissach suspension defeating it.

Including the Lexus transmission significantly lessened the basic design and effectiveness of the 928 suspension which is built around the torque tube eliminating torque bias on the rear wheels.

[Normy]

[QUOTE=Plexus928;6304211]

Originally Posted by rich

Why did you replace the rear mounted trans and Weissach rear suspension? Weight transfer and handling just left the room. It will work but where's the improvement?[/QUOTE
Weissach still there,from what I have read, it was an early 4 wheel steer set up, from experience with several 300zx 's cars handle better with it disabled , I''ll see how it handles when it's up and running and take if from there.
Why would I replace the rear mounted trans?
for starters, it's design dates back over 35 years, it's 3 speed,(OOOOEEEE!) and apart from costs of parts and overhauls, I don't think it would handle the power of the engine if I chose to feed it a few steroids.
the 5 speed lexus trannie is 21st century,electronic controlled, I wish I'd been able to score a front cut from the year later- 6 speed auto, (from 2008 -8 speed auto)
Handling: the engine and trannie weigh less than the porker engine on it's own, as you can see from the pic's the engine is mounted further back, and another200 pound weight loss at the back end, all the weight still between the front and back wheels rough estimates indicate it will still be close to 50/50 (but about 300 lbs lighter
Also , I heard a rumor that cars that don't have a transaxle can still get around a corner

Lets handle this one one at a time:

1. The 928 was designed in 1973. That is 38 years ago.

2. Yes, the passive rear-steer Weissach suspension was a reaction to none other than the 911 and its trailing-throttle oversteer problem....and an over-reaction. The 928 handles extremely neutral. It is a well balanced car, and bites nobody.

3. The M28 aluminum engine weighs about 565 pounds. We all know it. There is a reason for this- It is a big block. The bore spacing is 122 mm, about the same as a 440 Dodge or 454 chevy. Arias a few years ago produced a 32 valve 502 big block chevy with a special crank to turn the timing belt for a pair of Porsche 928 heads; That was probably the biggest Porsche 928 engine ever built~

-At 502 cubic inches, probably the biggest Porsche engine ever. If you can call it Porsche. Arias called it an "Arias"

4. The M28 made 330 hp easily with stock cams and pump gas. This from only 4.7 liters.

-In 1985, MotorTrend magazine had an article about the 928 automobile. They stated that the 928 was the only car that they would ever feel comfortable putting 6 inches from a wall at 150 mph while they didn't own it. The car was so stable at speed that it was a non event. Hello? The 928 was designed as high speed transportation, not as a toy.

The 50/50 weight distribution means that the car handles neutrally. Moving the engine back will tend to disrupt this, though moving the transmission forward might make up for it.

While that's a cool conversion, the question I have to ask is why? After all your hard work....you've achieved an....'82.

N!

[Plexus928]

The only way to find out is to do it, hypothesising is just another way to waste time, I'll be in a position to give an opinion based on a working driving model in about 4 months.

[not_hans_stuck]

Plexus,

Please post your results. I think the one thing we can all agree on is that we're interested in the results.

What are the perf specs of the toy engine?

H

[not_hans_stuck]

Originally Posted by rich

So your copying a Lexus? Why not just buy a Lexus. And there is no way your going to convince me you have 50/50 in that car. Put it on the scales before you get too far along there.... I think you would have to stick that Toyotee engine sideways under the dash and then maybe you would be 50/50.

And the Weissach is designed to change the scrub radius of the rear tires when the car is pushed through a hard corner improving traction, handling . The G load works the suspension. I have every reason to believe the ZX copy failed because it was a poor copy on a cheap car that would flex before it could deliver enough G force for a Weissach copy to work properly. The patented design improved the 928 and it can't be disconnected as you put it. It's a built in design.

I'm all about the custom stuff. I think the Alien and our 59 Bugeye are proof of that. But I have always thought there has to be a real improvement in performance and handling or whats the point?

I dont thi k it was scrub radius. I beleive it was toe compensation. Theres a floating link in the trailing arm or Transverse link or something.

I used to have this really cool little yellow book that compared the 928 and ford fiesta suspensions from a total mathematical perspective. It was an awesome book but i lent it out and i cant seem to find another copy. Anybody here ever heard of it?

H

[not_hans_stuck]

[QUOTE=Normy;6305904]

Originally Posted by Plexus928

Lets handle this one one at a time:

1. The 928 was designed in 1973. That is 38 years ago.

2. Yes, the passive rear-steer Weissach suspension was a reaction to none other than the 911 and its trailing-throttle oversteer problem....and an over-reaction. The 928 handles extremely neutral. It is a well balanced car, and bites nobody.

3. The M28 aluminum engine weighs about 565 pounds. We all know it. There is a reason for this- It is a big block. The bore spacing is 122 mm, about the same as a 440 Dodge or 454 chevy. Arias a few years ago produced a 32 valve 502 big block chevy with a special crank to turn the timing belt for a pair of Porsche 928 heads; That was probably the biggest Porsche 928 engine ever built~

-At 502 cubic inches, probably the biggest Porsche engine ever. If you can call it Porsche. Arias called it an "Arias"

4. The M28 made 330 hp easily with stock cams and pump gas. This from only 4.7 liters.

-In 1985, MotorTrend magazine had an article about the 928 automobile. They stated that the 928 was the only car that they would ever feel comfortable putting 6 inches from a wall at 150 mph while they didn't own it. The car was so stable at speed that it was a non event. Hello? The 928 was designed as high speed transportation, not as a toy.

The 50/50 weight distribution means that the car handles neutrally. Moving the engine back will tend to disrupt this, though moving the transmission forward might make up for it.

While that's a cool conversion, the question I have to ask is why? After all your hard work....you've achieved an....'82.

N!

The M28 is 565 lbs, eh? A Ram Jet 502 is only 602lbs (cast iron block, alu heads and intake). It's a 500HP all motor, fire breathing big block. That might be interesting. You'd need a different plenum. The Ram Jet plenum is a high rise. Hmmm. Wonder if you could squeeze that in there. It's a narrower V than the M28.

[Normy]

[QUOTE=not_hans_stuck;6307006]

Originally Posted by Normy

The M28 is 565 lbs, eh? A Ram Jet 502 is only 602lbs (cast iron block, alu heads and intake). It's a 500HP all motor, fire breathing big block. That might be interesting. You'd need a different plenum. The Ram Jet plenum is a high rise. Hmmm. Wonder if you could squeeze that in there. It's a narrower V than the M28.

I think that in the end you'd find that an M28 would make about the same power as the big block chevy, especially with the cylinder barrels bored out and replaced with steel cylinder liners. There is a group up in Wisconsin with an M28 with 7.0 liters of displacement, and though I don't have the numbers memorized, I do remember it wasn't hard at all to make 500 hp with a 6.4 liter M28 with 4 valve heads that Devek used to produce. That 500 hp? That was with stock heads and cams.....

6 of one, a half dozen of another. One is worth more; Take your pick-

N!

[not_hans_stuck]

Prolly right.

[Danglerb]

Originally Posted by Plexus928

The only way to find out is to do it, hypothesising is just another way to waste time, I'll be in a position to give an opinion based on a working driving model in about 4 months.

It not exactly reading entrails to say removing the torque tube largely defeats the suspension design, where the lack of torque bias is a key element.

[not_hans_stuck]

Originally Posted by rich

Ok, so no real numbers on your engine right? I still don't get it. Why would you go through all the time and money to install a chevy in a 928? What is the attraction to the 928 for you? It's clear it's not the engine. I mean you really are not building a Porsche right? Is the chassis that much better that you couldn't just use a camero? And for the money, time, and work it takes to do it you could have a Corvette.

So when you race do you register the car as a Porvette or a Chevsche (chev-A) or... Maybe a Chorsche (chore-sha) I'm not trying to be a smart ass I just don't get the mix when Chevy makes a 4 passenger fastback sport car with the same V8 engine you are trying to install in the 928.

Porschelet

[Danglerb]

When you race generally engine swaps get classed as unlimited, as in your grouped with purpose built tube frame race cars with few restrictions on engine size (they will be MUCH faster than you). If you are lucky some may class it on rwhp/wt. Lots of Porsche events require both engine and transmission to be Porsche.