pcar928fan

The 45 in that numerical designation IS the displacement. 4.5L... The last one was a 430 = 4.3L, before that 360 = 3.6L, 355 = 3.5L... You get the point. Does not apply to the V12 Fcars though.

Remember those motors are SO MUCH newer than our poor old motors. Ours were state of the art in the '70's but they barely changed over the years. Not to mention these bad boys rev all the way to 8500 and are designed to produce top HP at the high rpm...they don't make much Tq though. Ours are the opposite...big Tq (at least in the GTS's) and lower HP...

EspritS4s

A little searching of the archives goes a long way when it comes to the topics you are asking about. Strokers vs. SC and then SC vs. SC and even SC vs. turbo has been discussed, extensively, in multiple threads.

928man

Greg: So you actually built a 600HP engine, wow, even with a kevlar clutch a 5spd wouldn't survive a 600HP Stroker? Or would there also be transmission problems(street driving only) with a 5spd? Were any modifications necessary to the automatic transmission to handle the horsepower? how long does it take to build a stroker, what is the displacement, and compression ratio? Is there a range of cost on an engine like this, or would you rather not say right now? Why would a naturally aspirated car with 360HP beat a 500HP S/C car, i don't understand? any comments would be appreciated, thanks, Bill

928man

James: I see about the model designation, so for a 4.5liter engine, the 458 Italia is putting out a lot of horsepower but at very high RPM. What is Ferrari doing to get such horsepower, are they using exotic material, metals etc? I know that even in the old V12 models the horsepower was always much higher than the corresponding Torque for those engines, i guess they always ran at higher RPM's to get the horsepower compared to the american V8 engines? Bill

blown 87

Then we need a better manual trans and drive train.

928man

Excuse my ignorance but compared to a lot of guys on this site I'm a newbee, even though I've had 3 928's over the past 12 years, these guys are a wealth of information about 928's. The more you learn, the more you realize how little you know about these cars. Personally, I think Porsche should have stuck with the 928 design, but I guess the sales numbers, price, and times were wrong to do so. Today, even the least expensive new 911 is way over the amount of money I could ever consider spending for the performance your getting for the dollar, just my opinion.Bill

pcar928fan

Bill, I will let others answer your HP vs. Tq vs. displacement question. I don't know the answer. All I know is that you pick which one you want and go that direction. Look at a diesel engine in a big tractor trailer. Most of them are inline 6's and pretty big displacement but they make very little HP but 2000 lb/ft Tq! Maybe 250 Hp with that. Then you have the little Fcar V8 and it is making close to 600HP but only 420 Tq or something like that. It is always a trade off and I am not sure how things trade one way or the other to make more of one or the other...

IcemanG17

928man

By far the MOST important ??? is WHAT IS YOUR GOAL for the 928 you plan on building?

If you want a HUGE dyno number on a street car, that is street driven with the occasional drag race or dyno pull...then boost is the way to go, it makes the "biggest" numbers for the least cost....

However....if you intend to drive your monster 928 to the limit often and expect it to live for a while, then a Doc Brown stroker is the way to go....His stroker engines are NOT cheap, but are the most proven in the world....which is why people ship 928's from all over the world to him to get a stroker....

It all depends on what you are building the 928 for.....a dedicated race car, Open road racing, or just a powerful street car.....Doc's engines will suit all three......

I consider myself an EXPERT in blowing up 928 engines....having personally blown up 3 road racing....and have 1st hand knowledge of another 4 blown road racing engines..... IF it was my checkbook, I would call Doc.....but my racing budget isn't quite to that level.....yet :>)

928man

James; what you said makes sense to me, thanks for your honesty, I certainly don't have the answers, well, when the time comes I'll decide what to do, but a stroker @ 600HP would be some motor, automatic or 5spd in a 928, that's for sure. Bill.

Rob Edwards

Bill-

As Greg said, no question that supercharging is the best bang for the buck- if I didn't live in California (and live so close to Greg Brown's shop....) I would have gone that route. There are a number of good S/C solutions but the key to them all is good tuning post-install. (Good tuning applies to supercharged, turbocharged, or stroked engines, of course......)

Against my better judgement, here's a rough cost datapoint for one of Greg's strokers- remember that every stroker is a bit different from the next, as new developments arise. My build started in December 2008 and went 'live' in July 2010. (Someone referred to the December half price used part sale at 928Intl, I managed to score a '91GT motor for $2750- that became the 'donor' engine.)

My engine has Greg's standard 104mm bore shortblock, Moldex crank, Carillo rods, JE pistons, ported heads with 39 mm intake valves, DLC'ed lifters, and base-circle reduced GT cams. Pretty much every single part other than the block, head castings, exhaust valves, intake, valve covers and hardware is a new part. Including the donor engine, my parts tally is about $25K, and the labor tally is about $15K, so $40K-ish. Keep in mind that a big chunk of the labor is outside labor for having the block bored and Nikasiled, modding the cams, etc. Some of the labor is Greg fixing stuff that I messed up when I disassembled the donor engine, and some is extra cost that I incurred by working alongside Greg, 'helping' with the assembly steps that he could have done much more quickly without me in his hair...

My engine is set up to look as stock as humanly possible for the fine folks at the California Air Resources Board (though there's certainly nothing wrong with building a 'clean' engine....) , so I'm constrained by the stock intake. To get to 500 crank hp naturally aspirated, you'd need a different intake. The coolest option right now is one of Mike Simard's ITB setups, which used to sell for $3300, not sure what they cost now. Going to ITB's necessitates a lot of wiring and engine ECU changes, there are several options for this but you'd either better be byte-savvy or have good access to someone who is. Greg's 600 hp motor runs these ITBs- here's the thread if you haven't seen it.

https://rennlist.com/forums/928-foru...o-results.html


600 hp through a 5 speed is going to be hard on the 5-speed. My engine first dynoed at 370rwhp/405 tq, I have added Greg's exhaust since then but haven't gotten the chance to re-dyno. It's plenty fast for my driving abilities...... I keep losing stoplight encounters 'cause I haven't figured out how to not light up the rears. Good problem to have, I guess. Anyway, the 600hp engine lives in a '93 GTS Automatic, with some tranny mods. Should be an epic ride....

928man

Iceman: Durability of the motor @600HP would be the most important factor and being able to drive it fast & often would be the goal(street), the car would be driven to take advantage of the HP, not just blipped fast once in a while. I know aston martin was getting 520 HP out of their V12, and that was back in 2004(Vanquish-S model), and that was a pure street car rated to go to 200mph, even now, they sell for starting at $90k Ahead of its time, in my opinion. Is Doc Brown from CA.? I don't remember, was the Devek 928 a 5spd, i always assumed it was. The durability of the 928 motor was always the biggest thing for me about the motor. i guess you know all about that, it must take a lot to blow one up.bill

928man

Rob: Many thanks for the thread and information about your motor, that's some setup you have, i figured it would require a lot of custom machine work for the parts. that motor is a work of art, sounds like your getting around 500HP or so from what you said. So the 600HP motor with the automatic is yours or someone else's? In Penna if you drive the car less than 5,000 miles a year it is exempt from emissions testing. Is the motor in the GT or GTS? Bill

danglerb

600 hp will have a list of things to worry about before the motor. Torque is going to exceed the limits of tires and suspension in all lower gears, maybe all the gears. When the tires hook up the half shafts will snap. Automatics can be worked over to handle the power, but not a 5 spd.

Big factor in my thinking is that nothing I know of is going to make a 928 a "really" fast car zero to 50 mph. The suspension wasn't designed for the weight transfer easy to accomplish in a typical muscle car.

Rob Edwards

Bill-

If one believes the adage about 15% drivetrain loss for a manual transmission, then at 370 rwhp I'm at about 425ish crank hp. Pretty sure there isn't 500 hp in there with a stock intake. Last fall I installed a set of Greg's headers and catback exhaust, which were worth 33 hp/41 torques on a stock GTS, so I'd like to think that I can get to 400 rwhp with them on my GTS, as I have a lot more cam to play with. Maybe having dry sumped the heads will be worth a hp or 3. But the number will be whatever the number will be- I need to get back to the dyno shop, it's been way too long.

Pretty much every single piece in the engine is modded in one way or another. The crank, rods, and pistons all come in a box ready to assemble, but each is a custom piece designed to work with the others. As you might imagine, Greg's got some development time in each component before it went in the box. I really can't think of a single piece outside of some of the hardware and gaskets that is exactly as it came from the factory, even though that's the intended look underhood.

The other nice thing about a stroker is that it's essentially a new engine, so I have a little window period here where there's nothing in the engine compartment that's going to die of old age.

The 600 hp beast isn't mine, it belongs to andy-gts, who lives in Kansas.

Here are a few threads on my engine build:

https://rennlist.com/forums/928-foru...r-society.html

https://rennlist.com/forums/928-foru...ly-thread.html

https://rennlist.com/forums/928-foru...pril-11-a.html

And the story of the GTS that it went into:

https://rennlist.com/forums/928-foru...eap-twice.html

928man

Rob: So your motor is pushing roughly 460HP at the crank with the added headers & exhaust, thats still a lot of horsepower! So I guess 600HP with a 5spd isn't possible, but your setup with 460HP a 5spd still wouldn't be possible? I guess i'm trying to find a way but maybe there isn't any way. So an automatic is the only way to go, it is nice to think you have a brand new engine & congratulations on having such a magnificent setup! Lastly, can anybody tell me what a practical limit would be for horsepower at the crank for a 5 spd ? Thanks for all the additional threads, Rob. Bill