My 944 1uz-fe V8 swap

[George Elliott]

Can someone explain how air is prevented from going in?

Paul, "flow is obstructed by the air pressure present in the engine bay" Its like, if you stand in a shed with the door open and a 30 mph wind is blowing towards the doorway, you do not get a 30mph airflow past your ears..........unless you open a sizeable window in the shed..........[] The air flow thru the engine bay is mostly directed to the bell-housing / tunnel which seems restrictive, as outlined above. I would suggest your intention is good, and a good bonnet vent would help, including road spray, salt etc etc........[8|] George

 

[CarreraRSR]

Some bed time reading regarding badge panels and cooling. Sure focused on IC versus your oil cooler then some food for thought http://www.porscheclubgbforum.com/tm.asp?m=770898&mpage=1&key=944%2Cturbo%2Cbadge%2Cpanel%2Cduct

 

[Woodsport]

I don't wish to get off on the wrong foot with anyone here, especially with me being a relative newbie to this forum, but i just don't agree.

 

[os951]

Believe us Paul [] A friend of mine have a 1988 951 S. His car have a 924 Turbo vents. Since intake temperatures seems to be too high, he decided to add water injection to IC. With 924 vents this was a mission impossible. Water keep moving all other places than IC. When he blocked the vents, he got a nice spray directly to IC. With water injection, intake temperatures dropped 25-30C, which was a good result. Years ago we tested Temperatures with 951 original setup (plastic tunnel via bumper) vs.AIR vented nose panel (in the middle of your pictures). Original set up was far better. Without original plastic tunnel and just vented panel installed intake temperatures raised between 30-40C. We also made camera installation (Gopro) behind the nose panel and use classic wool yarn test, to see how does yarn move in the "massive" air flow our vented panel gives. We were more than surprised with the results. It moved all other possible directions but not to the IC. If you really want to have a useful cooler, use 951 plastic tunnel sealed over to your oil cooler, otherwise it's there just for looks. What comes to 924 Turbo vents, have you looked what is behind it? Nothing. 924 Turbo's have those vents just for looks. Also check out how 951/S2 radiator air flow has been arranged. If you look the picture i posted (that orange 924 in wind tunnel) you can see the point right away. Some of us have removed factory made plastic air tunnels. Most of them have run into heat difficulties. A friend of mine have a track 951. he ran without under engine plastic & aluminium shields. Also plastic panels under floor were not installed. He kept having serious heat issues. When he installed all those missing parts back, all of these problems vanished. Factory made very good job when they designed 951's. They used wind tunnels. All of these plastic parts are there for a good reason. If you want to make a good design better, you can add vents to bonnet, they seems to work well at least on turbo installations, where under bonnet heat is a issue. Also what comes to make a big IC to 951, it's in the most cases nonsense. Original item is very efficient. Air i led via that plastic tunnel i have wrote. When big cooler are mounted in front of radiator, most of have just that hole in the bumper which leads air. Original item have that plastic tunnel sealed around it, so all air is forced to run via IC. That will not happen with aftermarket coolers.Big aftermarket coolers make also in some cases impossible to radiator to get enough air to cool water. Most of us are not that good engineers to be as good as factory engineers were. Lot's of wild guess' here, what comes to make a great car to be better.

 

[Woodsport]

Ok thankyou for the explanation, however i need to see this for myself, when the car is driveable my Anemometer is going to be placed between the nose panel vent and the oil cooler so i can measure the windspeed hitting it and also the temperature of it, i'll report back exact data and repeat the test with the nose panel vent blocked off.

 

[GPF]

Part of the problem with the 924 vents is that they sit in a low pressure area. As such they are better for allowing a bit of heat out rather than airflow in….. I know, it seems counter intuitive, but does seem to have been proved time and again I'm afraid. Changing the profile of the badge panel may help - there is at least one type out there that bulges up to position the vent/s into the airflow but they can be a bit fugly []

 

[Woodsport]

My datalogging Anemometer will show exactly what airflow and temp that area sees with a vented panel, so i'll report my findings as soon as the car is driveable, certainly it cannot have a negative effect by venting the nose panel so i will do it anyway.

 

[edh]

ORIGINAL: Woodsport My datalogging Anemometer will show exactly what airflow and temp that area sees with a vented panel, so i'll report my findings as soon as the car is driveable, certainly it cannot have a negative effect by venting the nose panel so i will do it anyway.

It might have a negative effect if it's in a low pressure area & air is flowing out of the vents rather than being forced through the rad (and oil cooler)

 

[Woodsport]

Like i said, i find that impossible to believe with a 70mph wind hitting the car, interesting that this subject has had more reaction than the huge V8 sitting in the bay

 

[edh]

ORIGINAL: Woodsport Like i said, i find that impossible to believe with a 70mph wind hitting the car, interesting that this subject has had more reaction than the huge V8 sitting in the bay

Ah well, we know nothing about V8's in 944's, so just happy to look at the nice pics... []

 

[Woodsport]

LOL, on that note, i suspect my engine bay has completely different flow characteristics than a regular 944 anyway, so who knows.

 

[CarreraRSR]

Whatever hole you choose to put in the badge panel or bumper a duct direct onto the oil cooler will be required as Porsche did with the front mounted intercooler. A task I need to complete for my 924 turbo using a 944 IC. Without a duct the air bypasses the cooler via route of least resistance. A route you have in abundance above you oil cooler. The reaction you are getting is all with good intention and prior reading and experience. Not many V8 experts here. But there are of modified engines needing cooling

 

[Woodsport]

Appreciate that, i will also make some ducting to channel it straight at the oil cooler, thanks.

 

[Woodsport]

On with the show, tonight i got the heater lines done, usually on any engine swap they are a simple matter of connecting A to B with rubber hose, but my 944 always suffered badly with faulty heater controls, to the point where i was getting fed up fixing it, you name it my 944 had that heater fault, i even thought about replacing the whole thing and i'm a mechanic! Anyway as luck would have it i have no space under the bonnet for the stock control valve etc so with my car always blowing hot i can take this opportunity to ditch the Porsche way of controlling the heaters and use my own system, so i've used the complete heater valve and pipework from a Lexus Rx300 here which just happens to marry up very nicely with both the 1uz and 944 heater pipes.... so i'll run a cable from this and mount it under the dash binnacle somewhere.

No more heater problems for me ever again.

 

[Mike_Pollock]

Still amazed how quickly and neatly you can fabricate these things, experience helps I'm sure, but still impressive!

 

[George Elliott]

i'll report back exact data

Gents, I look forward to this, we will have to accept Paul's findings I think, and just imagine if........[8|] George 944t

 

[924nutter]

Point one; the 924 turbo has a divergent Naca duct in the bonnet. ( the schematic is for a normally aspirated car from 1978/1979 or before (no rear spoiler). Being divergent (as opposed to a caburretor choke body which is convergent) the latter sucks so the former must increase underbonnet pressure by definition. That coupled with the low pressure area in front of the 924 must counterintuitively suck some hot air out of the panel because the duct is on the bonnet at about pos15. Point two; if it worked so well to let air into the front of the engine, and bearing in mind Porsche probably still had the tooling for the slots if not the front panel (I know the S2 has a different curve) then a cheap solution would have been to use the slotted panel and situate the I/C right behind it, but if you take a close look at the 944 turbo the inlet for the I/C air is from a new slot underneath the badge panel, so with the greatest of respect I think Porsche themsleves have answered the question, because the new slot must have required more substantial retooling than re-hashing some of the existing tooling.

 

[Woodsport]

Thanks Mike. That may be 100% correct John, but the fact remains a statement has been made that putting a vent in the nose panel results in zero airflow directly behind it, zero cooling effect on the top of the radiator (my oil cooler area) and is a waste of time. Not looking to disprove anyone here, but i'm an old school mechanical engineer, i work with real world data and solve mechanical problems and with all due respect, the internet is full of shit. So when the car is driveable it will have a vented nose panel, and i'll mount my Anemometer directly in front of the oil cooler, drive it at 30mph and also 70mph (road and motorway speeds), the test will then be repeated with the vent duct taped over and i'll video the meter for good measure. That area behind the nose panel is not sealed, let's face it, the radiator would suffer if it was, and driving with 70mph winds entering that vent, there would need to be 70mph winds coming the other way to negate that or a sealed off area to see zero effect.... which i just do not believe. Let's wait for the tests, it's a long way off yet.... so on with the build.

 

[xschop]

The low pressure nose profile does prevent strong air velocity under free laminar air flow of the road, but air vents in the nose increases the flow when factory air fans kick on. My 5.3 LS engine cooled perfectly even with the NA radiator and nose. The 951 cars that have been V8 swapped all seem to need a bigger radiator core due the better aerodynamic front bumper cover.

 

[JagdHamster]

Looking at this pressure diagram closely and with a knowledge of bernoulli's laws by profession, I note that point 1 is under the car, just in front of the front tyre. It then graphs forwards to the bumper and only when it reaches point 10 does it move left to right over the car as expected.

So the low-pressure is actually above, in front of and on top of the front bumper (the airflow speeds up here the most, clearly, to travel over the car) However, if the air was able to flow through the car then this pressure drop would be much reduced. So the guys ares right; at the moment, the low pressure will drastically reduce cooling. However, if you make a pathway through the radiator and back out into the airflow (say at the windscreen, or even under the car like SMICs do), I think the pressure drop through the vents will be a lot less (maybe even a little positive pressure). That's the vital bit; making an exit for the airflow to rejoin.