Herr-Kuhn

Both will work, but the fact still remains that the only place a closed loop A/W system will outperform a properly sized A/A is when the water is chilled. You can confirm this on the Bell website. For street use or endurance racing, the A/A offers higher efficiency and it is likelt to be more repeatable as well. Tim is right, longer duration between boosted runs will offer cool down periods on a street car. I'm sure the A/W systems out there perform well.

A good race quality A/A will offer 1 psig pressure drop, maybe less but that is hard to obtain. I don't see 2 psig as an issue and I doubt any intercooler shop would say that much drop across a whole system is extreme. The mid range torque the turbo blows out more than enough to cover the delta here.

I've considered A/W for the new TT car and there is a slight possibility I might do that...but it won't be a decision based on the highest efficiency system. Based on packaging, maybe. I have to say the A/A ICs used on the Pacific NW TT car will offer very low efficiency...no ambient airflow path and stuffed into the cramped/hot engine bay. How is any flow supposed to make its way across those cores? Subaru still uses the engine bay mount A/A system...it is stupid in my opinion to stuff an A/A into the engine bay. Nor do I like the idea of cutting holes in a $2,500 aluminum hood.

Herr-Kuhn

Thats a cool photo Dave...but I have a question. Do you sweat your *** off when the throttle is mashed because you are chilling the cooler instead of the cabin? It is an interesting concept, what they have done.

I'm sure some of you have seen the super chilled A/A cores, where the Nitrous Oxide is used to chill the core down...or there are many water spray systems out there...works like those old bolt on VW air conditioners that used evaporative cooling...looked like a jet engine strapped to the bug! I hear those worked quite well. The water mist has been confirmed to add 10% to the efficiency...but like water injection it is based on a consumable fluid...water runs out, temps go up.

Fabio421

How does a bend in the system result in a pressure loss? I deal with hydraulics on a daily basis and I can see where a bend would decrease efficiency, lower fluid velocity, create some heat, and decrease your overall flow rates. But if anything, a restriction should increase the pressure slightly before the bend. Please explain.

Carl Fausett

I love that picture of the SVT Ford Lightening that DR posted. Man, thats a tough setup!

But, you cannot take pictures of THIS APPLICATION and say "its just like THAT application".

I raise these points that I have mentioned before and here they are again:

1) That's an example of a manufacturer building and designing for a twin-screw from the ground-up. Not an aftermarket application. BIG difference. You cannot say "this one will work because its just like that one" - it isn't.

2) That intercooler and plenum is not short like those we have seen for the 928.

3) That installation actually has a plenum under the twin screw - you can see it.
Probably room for individual intake runners too. (Why not, the whole assembly sticks thru the hood) I'm sure, since a major manufacturer is doing it, all the unique issues regarding a twin-screw have been worked out.

4) That intercooler is cast, and probably cast from the same material/alloy as the surrounding metals. The Ford engineers would have thought of this. Not like our twin screw applications, where we see welded-up intercoolers of one alloy that are seated inside a different alloy (Alusil) with different expansion characteristics.

5) That intercooler is not sealed down in the V where it will get super-heated like those on the 928 Twin Screw systems. It is up, out of the V, and has much cooler around it. It can be bigger this way, and it does not have to fight heat gain from conduction and convection like those currently in use on the 928.


I have every confidence that Dave's implementation and fit and finish will be much better than Andy's was. This I know.

So problems with Andy's installs that were the results of poor workmanship or poor secondary design (belt slippage, pulleys not lining up, mounting holes not lining up, etc) will probably be all gone. Dave will see to that.

What we have all yet to see is if the problems inherent in the primary design can be solved. Fueling, tip-in-detonation, etc. - and still get this package under the hood . Only after Dave gets some miles/years on some cars will we know.

DISCLAIMER: comments about twin-screws are based on kits and results of kits currently on 928's in the field. None of which are Dave's.

DR

Hi John,

>Thats a cool photo Dave..

No doubt!

>.but I have a question. Do you sweat your *** off when the throttle is mashed >because you are chilling the cooler instead of the cabin? It is an interesting >concept, what they have done.

The way I understand it, the system reservoir is "pre-chilled" and doesn't take from the main A/C 100% of the time so I would say that cabin temps wouldn't be an issue. To take a guess I would assume it is sort of like how a 928 with Rear A/C works. For those that have 928 Rear A/C systems it would be like driving down the road and turning your Rear A/C on and off occasionally, it does make a slight difference in the main A/C (front) system temp, but very little on a properly working system.

DR

Carl,

>(Why not, the whole assembly sticks thru the hood)

Actually it doesn't, see below.... (but it would on a 928 :-)

Tony

Ive seen first hand how this works.
"BLOWBEAST" (rob) has done this on his car. He runs a CS. A tremendous amount of work and inovation went into it, but damn it gets the water cold. Its perfect for street uses but on the track you wouldnt be able to use the system continuously.
I need to go down tot he Ford dealer and have them pull up the parts/schematic for it.
Id love to run 30F water through my I/C on the short runs on the drag strip.
I have never used ice, but would like to try at some point. Its just a PITA to haul the bags out there, storing them, then making a seperate tank to hold it with the room we have....

Efficient or not i dont care what you call it. You can argue all you want but there are 100,000 of vehicles out there, High performace vehichle as well, that run this "in the VEE" set up including numerous 928s.

Carl...John...To this point, My car and many other TwinScrewed 928s with a Vee intercooler are still faster than yours

DR

>That's an example of a manufacturer building and designing for a twin-screw from the ground-up. Not an aftermarket application.
>BIG difference. You cannot say "this one will work because its just like that one" - it isn't.

Of course, just a John eluded to earlier, we are all stuck with packaging our various system within the confines we have to work with.

For example if you or anyone else was designing a Centrifugal system for a 928 from the "ground up" with no space limits, you wouldn't suck air from the hot side of the radiator, or even mount the SC against the hot side of the radiator, both of which heats up the air and components more than they should be IMHO (and also greatly degrades the cooling capacity of the radiator). I would also assume the intercooler would not be mounted 8" or so above the exhaust manifold which put off more heat than anything in the engine bay. Also I would assume a ground up design would get the Air Flow Sensors/Meters, Air Guides and Throttle Bodies up and out of that hot "V' area where those "idiots" at Porsche put them on all 928s.

So unfortunately with the space confinements of the 928 engine bay a typical Centrifugal SC install has to follow this path...,it sucks hot air from the output side of the radiator (or thru a pipe in front of the hot side of the radiator) into a a heat soaked Supercharger mounted on or against the hot side of the radiator, then flows along the cylinder head getting heated from the radiant heat of the exhaust manifold, then enters the intercooler mounted above the radiant heat from exhaust manifold to be cooled down AND then is blown down into the "Hot V" of the engine via the Air Flow Sensor/Meter, Air Guide and Throttle Body before going up and and then back down into the cylinder heads.

On our 32v Twin Screw systems we are getting twin cold forced air from the front of the 928, that flows thru tubes along the cam covers (yes above the exhaust manifolds also) going into the Air Flow Meter/sensor, Air Guide and Throttle Body that IS NOT mounted in the "Hot V" and then flow thru the SC down into the the Intercooler (housed in an Insulated Lower intake) and then immediately flows up into the cylinder ports. FYI, our 16V Twin Screw Systems will be more like the later styled Top Mounted Intercooler systems currently being sold by Saleen (see photo below).

As was said, none of our "add-on" after the fact SC systems are perfect, but we have to work within certain confinements of the various systems. IF the end user (928er) could justify a mega buck totally redesigned engine compartment to over come all of these issues and were willing to do a lot of "undoable" mods to their 928s any of us could make them even better, but that is just not reality for the average consumer.

Just so it is clear, none are these statements are meant to belittle any system on the market as I have repeatedly said they are all good and have enjoyed every different type I have driven, but if we are going to talk facts we need to include all of the issues of the various compromises needed to SC a 928. Anywho, after all is said and done all of the various SC systems are done very well with what we had to work with to start with, within reasonable "sane" budget and space restrictions.

DR

Tony,

>I need to go down tot he Ford dealer and have them pull up the parts/schematic for it.
>Id love to run 30F water through my I/C on the short runs on the drag strip.

IF you have a 928 with rear A/C you already have most of he components you need to do this without sacrificing your main A/C system. Just think, with a little plumbing (which would be easy for someone of your skills) you could reach to the console, turn on the Rear A/C switch and NAIL IT!!!!!

mspiegle

Me too! I'm waiting for the '07 Sport Trac SVT to come out. Supposed to use a simliar setup along with a new engine that has 3 valves instead of 2. Since it'll be a new car, I shouldn't have any financing issues

I fail to see where he said that? He merely mentioned that OTHER large car manufacturers put the intercooler in the V of the engine. In fact, I don't think he mentioned "928" in his post.



Yup, there most certainly is a big difference. No aftermarket application will be just like a manufacturer setup. Not a twinscrew, turbo, OR a centrifugal.

If you're using an intercooler designed and rated to handle/flow 500hp, what's the problem?

oh yeah... whole thing out the hood....


Have you ever compared one of Andy's manifolds next to a stock cobra or lightning manifold? I doubt it. If you have, then you'd notice that they are strikingly similar. Go ahead, poke around and look for some pics. Do you want to know why this is? I'll tell you why... Andy modeled certain parts of his manifold after a lightning manifold. He actually bought one off ebay and studied it for quite a while.

This you know? How do you know that? Last time I saw a picture, DR's manifolds are incredibly similar to Andy's original production run of casted manifolds:

(DR, I hope you don't mind me borrowing this)


-vs-



Oh there you go... just had to open up that can of worms. You must really dislike Andy.

Warren928

That is an interesting idea, but if there was enough room in next to the evaporator (or somewhere just AFT of the evaporator) for a small heater (or small radiator) core device to be mounted AFTER the evaporator, you could just pump your intercooler water to that heater core and it would be cooled just the same without deleting the rear A/C or running expensive custom A/C lines. At that point you might just need some extra rubber line and a water valve to direct the water to the heater core on demand. Then your A/C remains in tact, just alittle less cool on those 1/4 mile runs.

Again, you might want to have a temp guage and sender in the intercooler water tank to see just how cold the water is. I think that in theory it may not get quite as cold as the but probably still VERY COLD.
Just an idea.
If somebody came up with a pre-fabbed simple add-on solution with either design I bet alot of SC folks would buy one for their shark. I know I would.

DR

Mike,

>Me too! I'm waiting for the '07 Sport Trac SVT to come out.

Count me in too, that thing is beyond BAD A$$!!

>Supposed to use a simliar setup along with a new engine that has 3 valves instead of 2

Actually it is a 4.6L DOHC 4 Valve version with Roots-type supercharger and air-to-water intercooler (sound familiar :-). FYI, the 5.4L used in the 2004-2006 F-150s, Expedition etc. is the 3 Valve version (my 05 has the 5.4 3 valve, GREAT torque)

Here is a link to specs for it ..

http://www.f150online.com/fordnews/view.cfm?nnum=204

and a link to tons of photos .. sadly no engine shots around that I have seen.

http://www.f150online.com/galleries/...w.cfm?num=8048

mspiegle

I see you've been doing more homework than me The DOHC 4-valve makes perfect sense now that I think of it. I just thought it was awesome that one of the big american manufactuers is stepping up to a more advanced engine design. Isn't chevy still using leaf springs on the rear suspension of the vette? eww

I actually wasn't *too* fond of the interior on the sport trac SVT... and the exterior is a bit radical looking for me.... but hopefully that's just in the concept vehicle.

I never really had a desire to own a truck/suv as my daily driver until I saw this thing. The ONLY thing i'm worried about is insurance killing me =(

Tim Murphy

Just to be clear:
All Murf928 systems get intake air from below the headlight and not from behind the radiator.

All Murf928 systems utilize a blow off valve that continuosly dumps the air from the sc when not in boost, so there is no heat soaking taking place. Other types of systems must recirculate the pumped air from the sc and I could see some heat soaking taking place in that situation.

All Murf928 systems with an intercooler, the intercooler is ALWAYS the coolest component under the hood, by a good margin.

DR

Hi Tim,

Happy Holidays, good to hear from you!!

>All Murf928 systems get intake air from below the headlight and not from behind the radiator.

Yes I was aware you have ungraded your system to get cooler fresh air on your Kits in your continuing evolvement and excellent development of your Kick A$$ SC kits. As I have said publicly before, your level of SC Kit fit and finish and continuing development was and is an inspiration to me. Keep those improvements coming, it benefits all of us in making our 928s more fun and more competitive!!