CT928

Here's a thought if you live somewhere cool.

(Please bear in mind this is purely guesswork and probably wrong)

You have an A/C Compressor on you car, but if it's not hot you don't need it.

If you were to replace it with the smallest compressor available then that would draw less HP then the standard one. (I might be wrong)

You could then install a small custom made evportaor for said compressor inside a custom airbox after the airfilter. Conecting this to the compresso would result in a massive decrease in intake temperature. Maybe it would be down to 5 degrees C?

Supposing that all the above were possible, is it likly that the resulting gain in power would be great enought to cancel out the drain of the A/C compressor and result in an overall gain in power?



Perhaps you could combine it with an NOS setup?

Now I'll sit and wait for the abuse to come down on me for having such an obviously obtuse idea... <img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" />

928ntslow

I think you will get more complaints on the function of the AC as it stands original. Down sizing will surely be a waste.Just yank the whole thing and lose the weight too if you are going to go to all that trouble.

I agree that if you are going to make any mods, get some cold hard facts first before you go to the trouble of tearing up parts. Do some tests.

You may want to contact Mark A or Mark K as far as the cowl cutting. They both have done this, but I do not know what they have benefitted from it. It wouldn't hurt to ask. I think there have been some testing and dynoing involved.

Ketchmi

CT928, your idea has some merit as Ford is doing the same thing with the new Lightning PU. It is supposed to be worth 50hp for a short time but it will not keep up with the 500+hp supercharged engine. It was thought of a long time ago but R12 is flammable whereas R134 is not. (Leaks would have been real fun!) As far as a normally aspirated engine, the gains would not be as much as with a supercharged engine which greatly heats the intake charge.

Keep up the free thought, it's the only way to move ahead!

Dave

Old & New

Again, as Pete and I suggested, without temperature and pressure measurements, you won't even know if you have any gains!

DoubleNutz

No intake gain at all in Ott's Garage as far as I can recall. However i will be in the garage with Louis tomarrow and look at the dyno's. Louis is working on new induction parts and products he is machining from billet aluminum.

Next the only reason the "assomeeter" may be only be calculating a bit more HP becuase the location of the intake air box is the same location where the the highest pressure is recorded on the 928 during forward motion, giving the slight effect of ram air induction (duuuuuh). However, just how were you planning to drive this new airbox creation in the rain?

These mods on the Porken 928 just don't seem real. Is this supposed to be some kind of sick joke that I am not getting?

DoubleNutz

This is such a true statement. What Louis Ott has learned from all of his tests, measurements and, experience trying to improve on Porsche's design cheaply is that it is EXTREMELY difficult to improve on much of what was designed into the car. There are little or no cheap or half assed power mods that are worth the time and money on the 928. Porsche did a fabulous job at building a car that is postively not giving up much power without sinking a few coins into it.

PorKen

"Next the only reason the "assomeeter" may be only be calculating a bit more HP becuase the location of the intake air box is the same location where the the highest pressure is recorded on the 928 during forward motion, giving the slight effect of ram air induction (duuuuuh). However, just how were you planning to drive this new airbox creation in the rain? "
Not sure if you're getting the point here so I'll try again.

This thread contains two ideas.

One, a radically open air box, with no little to no restriction to the path of incoming air. This air path from the atmosphere to the throttle plate is reduced by 4 feet, which promotes higher air velocity through the intake and better cylinder filling. Torque is improved which equals response.

Air temperature becomes a non-issue once the car is moving.

Two, a closed airbox with a large upward facing central opening, connected to an insulated hood sized duct, taking advantage of the large central void in the hood normally occupied by the engine sound deadener. The duct's radiator width intake replaces the upper fan shroud. This duct would receive pressurized air from in front of the radiator, in the same fashion as the factory air tubes but with increased volume. This idea would capitalize on the effect's noted above, IE airflow would follow a much straighter path to the throttle, plus have the benefits of slightly cooler air, and at higher speeds, slightly higher air pressure.

"These mods on the Porken 928 just don't seem real. Is this supposed to be some kind of sick joke that I am not getting?"
This, from the fellow that assembled the 'Predator' (PRDTR)?

"There are little or no cheap or half assed power mods that are worth the time and money on the 928."
How about an airbox made out of 'unobtainium'?

Dyno, smyno. If my finely tuned asselerometer didn't notice an improvement in my 'modified' car, then I wouldn't publish my results. I offer these ideas, with pictures, for persons who may be interested in experimenting with their cars, or learning how they work in more detail. I ain't sellin' nuthin'.

Persons 'not inclined to change original engineering' should stick to posting about detailing their 'factory perfect' cars.

ErnestSw

Porken,
First of all, I agree with you. The intake configuration is not dictated in the constitution.
What about the idea of replacing the cowling between the hood and the windshield with a mesh cover and using that space also? You could use a flap as a scoop and a rain cover.

PorKen

ErnestSW - when I get a chance I'll take some more timer pics 'the other way round', to see if there is some room to do what your suggesting...

DoubleNutz

GUYS been there and done this. All I am saying is there is not even a measurable difference or improvement. Simply put there are "NO" performance gains obtained. It was tested and and metered by Louis Ott and I almost two years ago. Not just on the dyno but with forward motion of the vehicle with testing devices and sensors wired to the vehicle. The results were ZIP in performance gains. BUT, if you are looking for something to do on a Saturday afternoon then this would be the ultimate project- after all it on took about 3months for Louis Ott to get good accurate and consistant test results. Heck, we even tried ducting cool air in from the A/C. So when it comes to wild azzed ideas we have tried and tested several as have many others like Devek, Tom Cloutier, and a number of other folks who participate with you on this list. In fact, the infamous Ott-GT is practically sitting on blocks with no engine as Loius crafts and machines parts and ideas that go way beyond the scope of anything that is propped up on this list for the 928- beleive me you guys have NO IDEA! I don't mean this as an insult to anybody's creative intellect but this hairbrained scheme you are chasing is very 1st grade (sorry, but , I had to say it). My point for going there is- "for god sake, come up with a new idea, and not one that has been beat and tested to death!"

I was just over Louis house yesterday changing the X-Over exhaust on Garths GTS and Louis' S4. Earlier that day, in between bleeding the clutch and brakes on my 996, we were discussing this topic and chuckled (along with another list member who lurks here on this list and is reading this thread - especially about the assometer because it may need some calibration). But, hey go for it- add a little more weight and complexity to a car that already well engineered in that area- but if not for that then beause this is was already tried and proved to be a waste of time.

DoubleNutz

Been there done this- and Don Hanson has been racing with it for almost a year.

Z

I think that it's great that more people seem to be thinking and experimenting with things as far as 928 performance goes. I just wish that more definite methods were used to gauge any results of those experiments. Results from a dyno, G-Tech, Road Dyno, or even wristwatch timing from point "A" to point "B" are far better than any ***-o-meter will ever be, whether it's been recently calibrated or not. Without any measurable and repeatable results, any testing and experimenting really isn't going to tell you anything much of any real use.

ErnestSw

BlueCarerra4,
On the one hand you dismiss air intake mods and on the other you say one is used by a racer. Did he do it for space reasons, or did he have some reason to think it might increase performance, and, if so, how does he know it's worth it?

DoubleNutz

Well its like I said several posts back...

ErnestSw

Does Don think it increases performance?