Another Small Block Conversion Argument

[Red Baron]

Originally Posted by Herr-Kuhn

I thought I'd share some comments I received from someone online regarding comparing the costs of converting 928S4 32V to twin turbo power vs. installing a SBC into the 928.

What's wrong with people these days? Can't anybody provide me with an objective argument and an ITEMIZED list of parts and labour to pull this off? Ironic how I offered to provide him my itemized costs on the conversion and as well to send the power and torque curves on the engine as proof of what's what...yet all I get back is this childish drool with absolutely zero substance.

As sent to me:

Re: 928 V8 vs SBC As i stated before, we live in 2 different forms of reality. Personally, I think you keep your nose in too many car magazines. Additionally, I could build a a small block chevy from used and junk yard parts that would run down that over-priced, overly complcated buzz-bomb of yours and send it into the weeds yelping like a stuck pig. Like I said before, torque wins races and horsepower sells motors, plus RPMs kill engines not torque and I won't have to twist it to 7,500 RPMs to get the job done..

I can't help it if you pay too much for a motor and are incapable of performing the work yourself. Keep driving that buzz-bomb and keep paying the fidler. Also, any moron knows you can buy assembled, Chevy small block motors all day long on the internet making between 500 and 600hp for way less than $15,000. Try Jegs.com Blueprint Pro Series Small Block Chevy 427ci/540HP/535TQ Engine for a little over 8,000 dollars already built. I could build this same motor myself, in my own shop for around $6500 dollars and it would leave that pissy little buzz-bomb of yours so fast you would think you entered the twilight zone. No ECU, either. Just a simple carburetor, no complex bull-****. Get real!

It must suck having a business web-site where any numb-nutted phffukstick (like this clown) can email you a bunch of drivel. There is so much stupidity in those two paragraphs that you'd have a hard time deciding where to start if you were to address it.

Just another "Big hat no cattle" racerboy wannabe who couldn't rebuild a Schwinn, yet alone a motor.

[Normy]

The conversions that I DON'T like to see are when some greeceball puts a chevy 350 in place of the original Porsche M28 engine.

The Porsche engine is a big block engine, yet it competes with chevrolet small block motors. This is a common misconception The M28 engine shares its bore spacing with the 454 chevy and the 440 cubic inch Dodge. The difference is measured in thousands of an inch. Arias, a high performanc shop in California, was able to mount 4 valve 928 heads on a customers 454 cubic inch chevy-based block. In the example, he was actually able to mount the heads, building, of course the very we are to get outmemberx

[superbird]

It isn't what beats what. 1/4 mile, road course, hill climb, braking, touring, and road race. There are very few cars ever built the will beat the 928 in all around great car. I've driven a lot of the older super cars (79-90) I've driven a Lamborgini Mura , a '67, beautiful, a work of art, but not a great road car. good but just not great. I've owned 5 mustangs, some mods some not, I can work a small block ford in my sleep and that goes for chev, morar and any other NA motor. This porsche engine however is a different kettle of fish.
It is overly complicated for what it needs to do. I'll give you that.
But this engine, when it winds up will give a sound that makes your heart spin up as well. The handling of the car is precise, pointed, and too dangerous for a rookie driver (skill is needed to drive a 928 no matter what model year)

I've built a lot of muscle cars, had some rare ones (which I sold before Barret Jackson) also had various british sports cars, but I've only one 928....the best.

[Danglerb]

The hot rodded 928 is very exciting, but not all that fun or practical to drive. The list of happy long term owners is TINY if it exists at all.

I have this idea in my head of what a sports car is, and the 928 even US with a 5 spd fits, the AT doesn't, and nether does a 500 hp Chevy motor in a 928.

My US 83 5 spd is fun. I can burn out in first with the clutch, chirp in second the same way, and generally run it wot even around town in first and second and not go to jail, or go sideways on dry pavement.

My Euro S 85 5 spd is fun, but a little scary. I can burn out in first and second with the throttle, and I don't even think about wot unless I find some empty road hidden away. This car will almost certainly get me into trouble, and I plan to give the HP a good 30% or more bump via hotter cams and 5.0L short block, and tame it a bit with new wide sticky tires, but it won't be a car to drive casually.

I wouldn't bother with a SBC for less than about 450 rwhp, and that going to result in a car almost unstreetable other than when babying it. What exactly would be the conditions where this would be the car I would prefer to drive vs the other two?

[Anthony10370]

The handling of the car is precise, pointed, and too dangerous for a rookie driver (skill is needed to drive a 928 no matter what model year)

Its funny you say that, my 1979 928 was the first car I ever bought/owned.
Of course, after doing the timing belt, front main seal, starter... I only got to drive it for a week before I found the other mile long list of needed repairs. That was three years (and one limited bank account) ago and it still doesnt run

It's still my favorite car though!

[Mrmerlin]

Anthony too bad you were not paying attention...
For a first car this may not be a bad way to learn though....

FWIW buy the best 928 you can,( the one with the most items refurbished)
the less you spend the more your going to have to spend, to repair the deferred items.

[rich]

IMO, the 928 is often misunderstood by nubes. The car was Porsches flagship when it was introduced. A luxo-sportscar with all the bells and whistles. Installing a chevy engine is like installing an elevator in an outhouse. It don't belong.

Renegade has sold kits to install a chevy in a 914 for many years. You can do it, but you have to ask yourself why? I have been to Renegades shop. They sell some good stuff. But when your done you have a chevy. I didn't want a chevy. I used to drag race back in the 80's I had a BB 427. It was fun and easy to build. Anyone can do it. I had three carbs on mine. No real challenge there. They work kind of like your toilet. Lift the cover off your toilet tank and check it out.

Like I said, anyone can swap in a chevy.

[harborman]

My final word on this subject. I think the 928 should be kept all 928. I have had my share of cars and it's a sin to put anything but a 928 engine in a 928 in my opinion. I would not be interested in buying one with a Chevy motor in it and consider it worthless. The car is not a drag car, go faster in one direction. It's a ROAD car, made for turns and it is fantastic! But people do as they wish which is fine I guess. I grew up in the big block go faster days when you could go buy a Dodge Hemi 426 Cuda and knock your socks off in a straight line, but these cars did not handle at all! Not like a 928, not even close!

[fb111]

Originally Posted by harborman

My final word on this subject. I think the 928 should be kept all 928. I have had my share of cars and it's a sin to put anything but a 928 engine in a 928 in my opinion. I would not be interested in buying one with a Chevy motor in it and consider it worthless. The car is not a drag car, go faster in one direction. It's a ROAD car, made for turns and it is fantastic! But people do as they wish which is fine I guess. I grew up in the big block go faster days when you could go buy a Dodge Hemi 426 Cuda and knock your socks off in a straight line, but these cars did not handle at all! Not like a 928, not even close!

Your arguement doesn't hold water. How in the world does putting a lighter more powerful engine in a 928 make the car handle worse?

[rich]

Originally Posted by fb111

Your arguement doesn't hold water. How in the world does putting a lighter more powerful engine in a 928 make the car handle worse?

How does pouring a can of beer into a glass of Dom Perignon make a better beverage? (blurp...)

[fb111]

I think its a bit dilusional to think the 928 engine represents " Dom Perignon" among the V8 universe.

[Herr-Kuhn]

We keep hearing how much lighter and more powerful these engines are but yet nobody brings real weights, power numbers and all costs to the table for discussion. A late model Camaro engine is 275-300 HP and turns like 6,000 RPM. Those are the cheap engines. If you want a 400 HP NA motor, it is more money and if you want a 600 HP NA motor it's a lot of money. You can't just point to a Jeg's catalog and say a 600 HP SB is $8000 when it has no manifolds or fuel management whatsoever. Then there is the issue of keeping all the accessories...if you aren't doing that then it's not an apples to apples comparison. Don't assume you can pull a 928 engine out and weight it with the AC and then put a SB in without AC and compare the weight. Apples to apples.

I never doubted the ability to have a Chevy powered 928 that is fast...what I doubt is that it can be built for "way less money" than it is to build or modify the 32V V8 that the S4 and newer cars came with. I also doubt it is significantly lighter.

I want an objective, side by side comparison of the costs associated with putting a 600 HP chevy into the 928's chassis (pick your poison, NA or boosted). Parts and labour!

I'm prepared to disclose all prices associated with making 600 HP on the 32V engine. I can show you invoices on what it costs. Until someone gives me an itemized list of parts and the labour time to pull it off I can only say that the comments floating around the internet and on these conversion websites is undocumented. Until the weight reduction, power numbers and the costs are documented it's nothing but hearsay.

I live in a facts based world and I really don't think that it's much to ask for a side by side comparison on the inputs and results.

[rich]

Originally Posted by fb111

I think its a bit dilusional to think the 928 engine represents " Dom Perignon" among the V8 universe.

Well let's make a car comparison then. A 928 Grand Tourismo with a MSRP at least double the cost of a GM car of the same basic design. A four place two door fastback car with an Alusil V8 with overhead cams and fuel injection with a near 50/50 weight balance, weissach suspension, 4 wheel independant suspension, 4 wheel disc brakes, compared to...

A four place two door fastback called a Camero. a tin box with the handling of a whallowing pig. solid rear axle with drum brakes, standard cast iron pushrod engine with a lame carb and a 40/60 weight balance. Under powered, poor quality, I owned a 1980 Z28 V8 5sp.

[fb111]

We're making engine comparisons not car comparisons. That was the point of my earlier post. Your defending cars I'm defending engines. Take the little 302 chevy of 1969 with its outdated carburator and I would think its numbers would compare favorably with any 5 liter 928 engine and do it 20 years earlier. You have a real issue with pushrods. I would gladly accept pushrods in the case of a 928 engine and not have to worry about the failure of a 6 foot plus timing belt breaking and bending a slew of valves. I have owned more 928's than any other vehicle and I love the package. But I'm honest enough with myself to accept the fact that the engine is not its strong suit. Its too big, too heavy, has oiling issues, and has the earlier mentioned issues with the ridiculously long timing belt.

[Herr-Kuhn]

The 928s engine was very advanced for its time. I'm unclear on how a comparison can be made on a 69 vintage SBC and any modern fuel injected overhead cam V8. You have to remember to compare on all fronts, not just power. By that I mean refinement, fuel economy, driveability, longevity, etc. It's a proven fact that a 928S4 engine can make the same power for over 200,000 miles if properly maintained. When these engines were new, they had some of the tightest tolerances of any engine made by any production manufacturer.

I'm still waiting for someone to bring the itemized list of costs to the table so we can have an objective discussion of the conversion costs between the two methods.

[Fabio421]

I don't think it makes sense to discuss power numbers and then compare a 1960's pre-smog engine to a later smog engine. Look at the same engines ( domestic ) pre-smog and post-smog and you will see that ALL manufacturers were struggling with making their engines smog legal and still make power. The late 70's and early 80's were a dark time for horsepower. Here is what I found with a little searching. Look at how much the HP dropped from the 1969 engines to the smog era engines. Maybe one of you that knows more about Chevy's can add more to the discussion.

Year: 1969 with 4 Barrel Carb
(Top Horsepower Model)
Max Brake Horsepower - 370 @ 4800 rpm
Max Torque - 380 @ 4000 rpm
Stroke - 3.48
Bore - 4.001
Compression - 11.00
Firing Order - 18436572


Year: 1981
The L81 was the only 5.7 L (350 cu in) Corvette engine for 1981. It produced 190 hp (142 kW) and 280 lb·ft (380 N·m) from 8.2:1 compression, exactly the same as the 1980 L48, but added computer control spark advance, replacing the vacuum advance.

Years: 1985–1992
The new 1985 L98 added tuned-port fuel injection "TPI", which produced 230 hp (172 kW) and 330 lb·ft (447 N·m). It was standard on all 1985–1991 Corvettes (rated at 230 hp (172 kW)-250 hp (186 kW) and 330 lb·ft (447 N·m)-350 lb·ft (475 N·m)). Aluminum cylinder heads (Corvette only) were released part way through the 1986 model run and continued through the end of L98 Corvette production in 1992. Optional on 87–92 Chevrolet Camaro & Pontiac Firebird models (rated at 225 hp (168 kW)-245 hp (183 kW) and 330 lb·ft (447 N·m)-345 lb·ft (468 N·m)) 1987 versions had 10 hp (7 kW) and 15 lb·ft (20 N·m) more thanks to 9.5:1 compression and a change to hydraulic roller camshaft. Compression was up again in 1991 to 10:1 but output stayed the same.


So in all cases, the Porsche V8 was making more power with less displacement than the Chevy engine of the same era.

[tmpusfugit]

It looks like we are arguing apples and oranges here, with a big dose of religion and politics thrown in. Seldom do those discussions ever lead any place productive, can this discussion be any different? So far, no, IMO. And we all know what opinions are worth.

I might entertain putting a DOHC Corvette ZR1 engine in a 928, or for that matter an all aluminum block and heads version pushrod engine. Or maybe the new Ford Coyote engine. But, as others have suggested, a similar amount of money invested in a 928 engine would be a more plausible exercise. I have done a couple of engine swaps (not into a 928 thankfully). My experience, take your worst case cost estimates and worst case timeline, double them both, then double them again. that should leave you close to what it will really cost you in time and $$$ to do a conversion such as a 350 into a 928. And when done you have spent $25k to make a $10k car now worth $3500. If money is no object, you have unlimited time to spend, and have access to a very well equipped shop, and you personally possess the patience of Job, a ZR1 would be fun in a 928. In that case plan to spend $15-25k for the engine alone....

[rich]

My point on the Camero and the 928 is an attempt to compare cars of the same design an a common year. Both with the same smog regs. Now anyone can put a crate engine into anything. But will it meet current emission standards at 600 hp? Will it even meet 1980 standards? And BTW: even a Corvette (which is not in the same car classification as a 928) of the same era was a plastic pig with no power. Had one of them also.
Then the second point is if you just want a chevy why not just buy one? You can get a 80's 2 door Impala with a 454 with about 180 hp and a bench seat.

Anyone can purchase a 928. Not everyone has what it takes to maintain one much less add performance without making in into something it's not.

And third, The 928 is closer to a BB chev is size and weight so I think we should be using that as a base for comparison. Now take a BB chev with 600 hp and have it meet emission standards and see what it weighs. also compare cost and fuel consumption. Good luck with that.

[Jon B.]

^^^^Is the Camero you speak of similar to a Chevrolet Camaro?

[rich]

Originally Posted by Jon B.

^^^^Is the Camero you speak of similar to a Chevrolet Camaro?

ah,yah.. what else was manufactured with a chevy engine and called a Camero?