According to the 944 workshop manual, the rods are forged steel/cast since Feb. 1984.

Well, there you go. You cannot just assume an 84 has cast rods.

i think he has a better chance of having forged rods. model year '84 cars came out in late '83.

I just ran out to the garage. Production date is 4-84.

Steve

the only way to tell is to actually look. It's weird how they make some with cast, and some with forged. doesn't make any sense to me.

Doh!

Still, with good engine management you should be OK. You just have less room for error.

My 84 says october 83. Does that mean i have forged rods?

no.

absolutely right.

The way I drive I really doubt I will have a problem. The car will never be raced or auto-Xed. With a couple hundred horsepower and not driving like an ahole hopefully it will hold together for a while. I probably will look into a baffle or scraper though as the thing really sticks to the road with the suspension upgrades. It's not anywhere near as fast as the 011 or the M3 but will outhandle both. They are both dead stock but still respectable cars.

Steve

it's not about driving style. it's about a/f ratios and ignition timing. adding forced induction changes so many aspects of your motor.

Dude, you are so wrong. It is ALL about driving style. I build top alcohol dragsters and if I choose to idle through the quarter, then I go through about 1 to 2 gallons of fuel and when I tear the engine down, it looks just like when I put it together. If I go through at full throttle, I put 18 gallons of fuel through it in the quarter mile and I often times have a melted piston or two at the end. Both runs have the same a/f ratios and timing settings but very different results at the end of the quarter. Driving styles and desired horsepower (engine computer settings) dictate the a/f ratios used and how much stress is put on the motor. And timing has NOTHING to do with crankshaft stress...unless it's not set correctly in which case the motor wouldn't run properly...if at all. The whole idea behind timing is to set it properly to take the stress off the engine. Forced induction changes the amount of air that flows into the cylinders...that's it. Of course if you cram more air into the cylinders, then to keep the optimum air/fuel ratios then you have to pour more fuel in as well. But driving styles dictate what air/fuel ratio you are trying for. When I am trying to go through the quarter mile at my fastest times, I shoot for the maximum amount of fuel I can put in the cylinder without hydraulicing the engine. (That means blow the head off because the fuel was still liquid when the piston came up on the compression stroke in case you are not familiar with the term). Sometimes when I'm just working with the car, I will change the driving style I want from the car and change the performance to a more moderate setting or change the way I drive it so I don't have to pay for that much fuel and tires every run. It's all about what driving style I want because that determines the computer settings and/or how much accelerator I use which determine the amount of stress on the motor. From your signature line, you drive a car with a turbine supercharger on it...do you have to use it or is it just there when you want it to be? You of all people shouldn't have to be told that driving styles determine how much pressure is put on the motor. You don't want that pressure on the motor...keep your foot off the accelerator...it's that simple. If you do that, the stress put on the motor is the same as if you didn't have a supercharger on there at all. I can't believe you posted that remark since you own one and should know how they work.

ok, you totally missed the point of my post. you can drive the car as a daily driver, but if your a/f ratios are like 17:1, it doesn't matter how you drive, you're begging for something bad to happen. the same goes with the timing, if you advance your timing, and then add forced induction without dialing it back, again, not good.



But the question is, what is the point of bolting on a supercharger, if your not mashing the pedal down?

I would not agree with that. Like other things, it's a factor, but it's far from all.

Which is a VERY different beast. VERY cool stuff, but the operating environment is tremendously different. In your type of racing major engine components are consumeables.

Again, you're only thinking in terms of your own specialty area.

Incorrect. It may be what you do with your drag engines, but timing does matter. To a point, advancing the timing will produce more power. However, due to other factors of forced induction, quite often a lot of timing will have to be pulled out of the maps with FA.

Wrong. It also heats up the air as it compresses it. This is a critical point as this affects everything in terms of tuning. That is why intercooler efficiency (and turbine efficiency for that matter) is critical. The hotter the mixture, the greater the chances of detonation. And as a result the more timing that must be pulled out. It also means AF ratios may need to be tweaked to run more rich to cool the mixture some.

Believe me when I say I highly respect what you do. It's some awesome stuff. But don't lose sight of the fact it's very highly specialized for one thing.

A good case in point. In other FA engines hydraliciing the engine is not even close to a factor. Also, you don't just try to add as much fuel as possible. Of course, with a road or a road race car, running lean means hotter mixtures so you cannot run as lean (relatively speaking) as one might like.

No. It's NOT that simple. Again, perhaps in your specialized world. There is a LOT that can be done with FA to affect the stress the engine is under. It's quite possible to built high boost, high hp daily drivers without killing the engine. Of course the more you hammer the throttle the more stress you put the engine under, but that is hardly the only factor and it's NOT that simple.

Guys:

In my particular instance I am looking at 175-180 RWHP not 5000. I realize there will be some additional stress involved but I actually will probably lunch the old tranny and / or clutches a lot sooner than I will break rods and cranks. All of you know way more about this stuff technically than I do. I am an engineer but I work in a totally different field. I started with a car that I had never even changed the oil in until I bought my wife the M3 a year and a half ago and flat bedded the 944 back to our house from our farm. She could no longer drive a stick comfortably due to fibro-myalgia so we parked it at our farm almost 6 years ago and I got her a Jag. Rather than sell the 944 (I tried and the highest offer I got was $4000) I decided to take a few dollars from selling one of my 911s and research a little and have some fun. My next door neighbor is a Porsche mechanic by trade and he urged me to do it under his alcohol stunted supervision. I initially wanted to take $10K and redo all the things that could go bad anytime soon, get some new shocks, wheels, and maybe coax a little more power out of the old girl. The money went quick so I had to rethink the budget' I got a few things from Pelican and stumbled across this forum. I initially approached the forum with the idea that all it would be was something like some of the Audiophile sites I frequent that are full of guys that think they can hear paint dry. I was definately 100% wrong about that. There are some really really knowledgable and helpful people associated with this group @ Pelican. I have gotten a lot of good advice and encouragement.

Hopefully with only 6PSI boost for now coupled with the MAF conversion, extra injectors and controller helping with keeping the A/F ratio relatively consistant, a little better exhaust flow, and not doing constant hole shots I can hold it together. I know I will eventually do an intercooler of some type as I am at least astute enough to realize the oxygen content is higher the colder the intake temperature is. I just have to stop the bleeding at some point and get in it and enjoy driving for a couple months, sort things out, and then take it down for a month or so over the winter.

I am using a local tuner who is big into the turbo Supras and Hondas, has a dyno equipped shop, and owes me some favors. I am attempting to use a baseline approach and just see what happens. He just redid a buddy of mines 91 Turbo Supra. He bought the car a year ago w/ 8800 original miles and had always wanted one but could not afford it until now. They bumped it from 8PSI to 14 and its definately a fast car, at least to me.

The stuff West is professing does have merits otherwise I would have just used something else. If I ever do get what I have been promissed it should be pretty cool. I also see potential fatigue problems but I anticipate the alternator bearings under stress and clutches being the weak links. Hopefully I am right. If I am I will have a car that weighs about 150lbs less than it did and has a 40%-50% boost in power with a better than stock suspension on a car that all of you know handles great to begin with. Also I like the way it looks.

Redoing the stuff like the headgasket was a good idea. When I popped the head off we discovered that the head gasket was almost gone. The belts were wasted, the fuel pressure regulator was leaking, the fuel pump was straining, there was a ton of sediment in the gas tank, the brakes were shot, etc due to the car sitting almost 6 years under a cover in our barn. That was my mistake. Basicly these things would have had to be replaced anyway to either sell it or drive it. While apart it cost almost nothing extra to do the good stuff. The ball joints and bushings were not necessary and the cylinder walls and valves looked almost new. I got 951 sway bars for $150 so that started the suspension upgrades. In summary:

I really hope I get my SC before legal recourse is involved and I really hope I get to drive this thing with the SC attached prior to winter. Oh yeah:

I really appreciate the support, Tom, CJ, etc

Steve / Go Cards

Driving styles are what dictates the tuning of the engine. The tuning of the engine determines what levels of stress is placed on the car's engine components. Yes, mine is very specialized but the engineering principles are still the same but the tuner has a different desired result. In my case it's to generate as much HP as possible within the shortest time frame no matter what the cost. With a daily driver, that's not the goal at all. Again, driving style goals are what determine where you are trying to go.

Agreed. But it's my driving goals that dictate that. If my goals were to make the engine last longer, I would have to change my engine setup completely. Still all about driving goals.

Please explain as I don't agree with your statement. It's all about how much horsepower you want from your engine. If you don't care about horsepower, then it's ok to drive an NA engine and they last a very long time. If you want more horsepower, then add some boost in there but realize that cuts into the life of your motor. There are ways to reduce that, but they still affect it to some degree. The laws of physics dictate that. Anytime you put more force on a rod bearing, it's not going to last as long....no way to change that.

You are correct, timing does increase horsepower but the question is why. If just advancing the timing always increased horsepower, then why are we putting superchargers on our cars....just increase the timing. Doesn't work that way though. It does to a point then it reverses to actually decrease horsepower because the spark actually happens when the piston is trying to come up. That's the only time that timing increases pressures on the bottom part of the motor to any measureable amount. The only engine I know of that actually tries to do that is Harley Davidson..... which is why they vibrate so much and leak oil but their goal is a certain sound...again all about driving style. In this case sound is the most important thing and so they tune for that. If you take timing out, then the spark occurs later in the cycle and makes it run differently but that doesn't affect the pressures on the bottom of the motor to any measureable amount because the piston is already on it's way down. Usually you want timing to help the engine which means you advance it to the point where it's not firing too late and reducing your horsepower but if you advance it too far, the engine is firing when the piston is still trying to come up....that should be the only time added stress is caused by timing. So if timing is set correctly, it doesn't add stress to the engine.

Ok, you have a point there because you increase air pressures, the air temperature increase proportionally, but that wasn't the point being made. The added heat doesn't increase pressures on the bottom part of the motor. Again, it's the driving style that dictates how much air is forced in there and how much more air temperature is added.


Agreed.

George, you are absolutely correct on this one, but I think you missed the point. The point is my driving style says that I need as much horsepower in the shortest amount of time possible. In a daily driver, your driving style doesn't dictate that. Your driving style dictates that you want some amount of horsepower but you want the engine to last past a quarter mile. Therefore, you can't dump 18 gallons of fuel into the motor every quarter mile. It's the driving styles and goals that dictate the tuning and engine pressures.


I somewhat agree but you can't deny that anytime you increase the amount of air and fuel that goes in a cylinder, the less life the engine has. Physics are physics. Yes, in my race cars, we take it to extremes and destroy the parts in a quarter mile. But the laws of physics still say if you increase friction on a part, the more it's going to wear, even if it's to some small amount. Let's take a factory 951. If my driving style says that I never engage the turbo, then I don't ever add extra air/fuel in the engine and the rod and main bearings never feel that extra friction and they do last longer....no way if you understand physics that you can deny that. If I now choose to put the throttle to the floor every time I get in the car. I've now maximized the air/fuel delivery every time the engine runs and the bearings feel that friction and do not last as long. Driving style does dictate the pressures on the engine. Now, can you do things to reduce those pressures...sure but those things will more than likely also reduce HP...and if that's ok by your driving style, then that is what should be done. If your driving style can't live with that, then you shouldn't do it but realize there are costs for that. There are reasons why race cars are rebuilt more often than street cars.

My point to the whole post is that driving style does dictate what tune I run which has a direct result on how much pressure the engine feels and how long it lasts. It's all about the driver and the driver's goals. The details of the tune were not the point. If I brought you my car and said "hey, build me an engine I can live with" and you didn't know how I drove, how would you know how to set it up and what needed to be done. Do I drive it to the grocery store and back or do I race it against the fastest cars on the track. I'm not trying to tell you how to tune or build a road car, I would have a lot to learn before I could do that, but I am saying that before you can say you need bigger rods, more pistons, a supercharger that requires 800 hp to turn it...I would really need to know their driving style before I could make that determination. Driving style dictates everything!

jgpOrsche....to answer your question about why have the supercharger if you never use it....it's all about style. That's like asking a person who has a show car ...what's the point if you never get to drive it. It's different for everyone...you are trying to apply what excites you to everyone else and that doesn't work. My 16 year old daughter wants a turbo just because she thinks they look better...although I'm fearful she might just learn how to use it...rather heavy foot. But sometimes, it's just about what looks good that excites a person. It's like the old man that dates a young girl...probably doesn't utilize the maximum horsepower there (if you know what I mean), but damn she sure looks good! :) And for an 80 year old guy, that might be just enough. Made Anna Nicole rich, didn't it? ...although I personally don't see any high performance parts in that engine! Maybe at 80, your eyesight isn't that good either!

My gut says shikza will be fine.

I watched some Top Fuel today. Never really watched a whole race bracket before.. I'm a big Formula 1 fan. I talked about engines last night with a guy who's big into street drag trucks (he's currently installing a 7.2 litre V8 into a 80's dodge). I know my fair share about engines but I got schooled when it came to talking V8's with him.

I asked him if it was an interference engine and he laughed. I guess thats not a big problem with V8s....
"Does it use balance shafts?" Um.. No.
"VarioCam?" What?
"Is it aircooled?" Are you joking?

The speak of Porsche is much different.

To counter his 800HP nitrous fed monter talk I showed him Porsche's 997 Turbo 'Masterwerk' video on their site (A must watch if you haven't). It explained all the technologies used on the 997 Turbo.

When the movie got to the variable geometry turbine.... the dude lost it. Literally lost his &$@%. After he regained composure he told me that that was the absolute most amazing bit of automotive technology he had ever seen. And this isn't a guy who gets excited about trivial things...



So it's nice to see someone used to 8 second 1/4 miles absoutely blown away by a brand normally just shrugged off in that community...

Steve, I think you'll be fine. Again, I think engine management is critical. I've said this often on Rennlist (I'm not terribly active here but am on Rennlist). There is no reason what you have planned cannot be done well, although I really do think you'll want an intercooler up-front.

This effect is minimal compared with what it really does for you. The hotter intake charge leaving the turbo puts the engine closer to or into detonation. The temps at a compressor outlet are raised significantly (350* is not out of the question). The intercooler can dramatically lower the temps giving you more options with engine management, e.g., more advance, run a little leaner, etc. Or, it simply can keep you out of danger of detonation (the reason I think you'll want one from the get-go).

Some folks may consider this sacrilege, but I think with this you are in better hands than any Porsche shop. Too many Porsche people have too limited linking on putting a turbo or SC on a NA 944. The Japanese car tuners are MUCH more free thinking and good at finding solutions for FI. I have even more confidence than ever that you'll be fine. And if the joker who sold you the kit doesn't come through, I'd wager these folks will probably be able to engineer at least as good a solution.

Good luck Steve. I think you'll do fine. Good to see someone not listening to the nay-sayers.

exactly the kinds of things i was trying to say.

incorrect