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I just installed a w25 ram air hood on my 1970 Cutlass. Like any ideas on a air cleaner setup to utilize the fresh air benefits. Thanks.
Pictures would be Great 👍.
Don't know if I have any pictures. But back in the day when I couldn't afford the air cleaner top with a flapper I removed the standard air cleaner lid and glued a foam ring to the top lip of the air cleaner base.
I used a dual snorkel air cleaner I found on eBay off a early 70’s Corvette with a cowl induction adapter and the foam from a factory W30 OAI air cleaner.
Different hood, my cowl set-up. I seen a few videos on YouTube. Where different air cleaner setup are tested on engine dyno. The ones that added the most HP were the top air cleaner filter. I was so impressed, I added to my car. Air does not need to make a 90 degree turn into Carb. Tried to build a box to incorporate the whole carburetor into the air ram. From the small heat defector under the carb. But that was beyond my ability. Insulated a industrial rectangular baking pan on top of carb air cleaner base. Just fits. You can just see the cleaner base lip that the air filter would normal sit on in the last photo. Foam from Summit racing.
Coppercutlass velocity stack setup was the best HP gain on the YouTube dyno. Would think that the best way to go for W25 ram air hood.
Did add mustang louvers above the headers. To get heat out of the engine bay. Working on some other ideas to get heat out of engine bay. GNX louvers that work next. Out of the box. Trying anyway.
Aren't re-pop setups available from Year One, the Parts Place or similar? Would have the added benefit of a factory look rather than a homebrew Frankenstein vibe.
Aren't re-pop setups available from Year One, the Parts Place or similar? Would have the added benefit of a factory look rather than a homebrew Frankenstein vibe.
.......or, low buck, hot rodding? This is the racing section, afterall.
Highway, how much rain came in through those louvers?
The issue with the w-25 is it had to look cool, be cool, yet be reliable, hence the flapper. Previous years (68-69) went through the thermacs and 66/67 just didn't care and it was open all the time.
If I wanted a cheap, somewhat looking ok, air base to mount to a hood, I'd go get a 6 quart, 5 buck plastic oil pan, put a hole in the bottom for the carb, and trim the top to fit, then put sponge on the lip.
Highway, how much rain came in through those louvers?
The issue with the w-25 is it had to look cool, be cool, yet be reliable, hence the flapper. Previous years (68-69) went through the thermacs and 66/67 just didn't care and it was open all the time.
Moving, not much. Stop at a light, Its coming in. I am sure its going right to the headers. Rain is coming up from under the car anyway. No problems so far in the few downpours. Not like we get much rain in St George, UT. Have foam door insulation on the lower cowl intake. Keeps rain from getting into the carb. Like a little dam. I can see that works from the driver seat.
Just saw your plastic oil pan idea. Plastic sounds like a bad idea over your engine. As a Fire Sprinkler Designer. Plastics are one of the hardest to control in a fire. Playing with fire
Thinking about the cake pan idea. Getting a 16 in. One, cutting a hole for the holley carb, putting the 14 inch air cleaner with the k&n top on it. Then putting the foam around the lip of the pan. Thanks for all the responses. All great ideas and setups.
In terms of the 'cool' factor, the W25 hood probably wins out over the under bumper scoops of 68/9. No question it beats the 66/7 set-up since, if you didn't know what you were looking for, you'd have a hard time seeing those. However, in terms of delivering more airflow to the carburetor, the 66-9 designs almost certainly outperformed the W25. The earlier designs were engineered for function more than flair and put the hose openings directly in the air stream. The opposite is true of the W25. Form won out over function. The openings were too far back on the hood and far too low to really be effective. There's a 1-2" boundary layer of stagnant air across the hood so the W25 openings provide little, if any, ram effect. True, the carb is able to breathe cooler outside air but it's not 'forced' into the system the way it was with the earlier designs. The same is true of similar designs of the time - for example, the Buick GS. Great looking scoops on the hood but really no performance benefit whatsoever. Some of Chrysler's bigger air boxes they were using in the mid-late '60's were good as they effectively pulled in air from above the boundary layer. Chevy took advantage of the high pressure air at the base of the windshield with their cowl induction set-ups. For the most part, the musclecar "ram air" systems were pure marketing and styling with little, if any, engineering benefit.
I read a story several years ago that there was quite an argument within Oldsmobile when the '70 model was being designed. The engineers were insistent that the W25 hood was ineffective and only 'eye candy'. The stylists argued they needed a 'wow' factor with more impact than the previous designs and won that fight. Cool hood but if you're prepared to fabricate your own air box to force cooler air into the carb, you'd be better served trying to snag the air from someplace other than the factory hood openings.
None of the "ram air" systems on musclecars resulted in any usable positive pressure. The 1966-69 ducting created so much turbulence inside the duct that the pressure at the carb inlet was no different than without the ducts. The W25 scoops were at least at the leading edge of the hood, which is somewhat of a high(er) pressure area. Some factory hood scoops from the 1960s were actually LOWER than ambient pressure (think Ford and Chrysler shaker scoops, for example) The high pressure areas are the grille, leading edge of the hood, and base of the windshield. As you've pointed out, any HP gains were due to reduced inlet air temperature.
Red/orange are positive pressure. Yellow/green/blue are negative pressure and are actually sucking air out of the carb.
Moving, not much. Stop at a light, Its coming in. I am sure its going right to the headers. Rain is coming up from under the car anyway. No problems so far in the few downpours. Not like we get much rain in St George, UT. Have foam door insulation on the lower cowl intake. Keeps rain from getting into the carb. Like a little dam. I can see that works from the driver seat.
Just saw your plastic oil pan idea. Plastic sounds like a bad idea over your engine. As a Fire Sprinkler Designer. Plastics are one of the hardest to control in a fire. Playing with fire
Some plastics will go at 100C. Considering there's plastic on the carb, I doubt above the carb will get that hot, especially a quarter mile at a time.
Like Joe has indicated with the Prius (lol), OAI is about cold air, not ram air. Most cars have it now, they also have a plenum void to remove the sucking sound as it is uncouth, I guess.
Is it better if I use a Volvo?
Hey, there are only so many images available on Google Images.
(note, the color scale on this graphic is different than on the first one)
Some plastics will go at 100C. Considering there's plastic on the carb, I doubt above the carb will get that hot, especially a quarter mile at a time.
Like Joe has indicated with the Prius (lol), OAI is about cold air, not ram air. Most cars have it now, they also have a plenum void to remove the sucking sound as it is uncouth, I guess.
You want pressurized air; it's supercharger time.
100C is 212F. It may get up to 200C under the hood. Think I could cook a hot dog, over my louver OK if the plastic is made to stand up to the heat.
Considering that modern engines run coolant above 100C under normal conditions, and have plastic intake manifolds, I think that problem has been solved.
While not typical in automotive applications, we frequently use very high temperature plastics in spacecraft. One favorite is Vespel by DuPont. About 570 deg F capability. We often use it as a thermal isolator for thrusters and heat shields. Of course, there's also Teflon.
While not typical in automotive applications, we frequently use very high temperature plastics in spacecraft. One favorite is Vespel by DuPont. About 570 deg F capability. We often use it as a thermal isolator for thrusters and heat shields. Of course, there's also Teflon.
Interesting. I've not anything that goes anywhere near that. Closest we have is some odd closed cell dense foam molded into shapes that now seems to be showing up on the engines. I believe it helps keep the firewall cooler as the right head on a V engine is right there on a transverse mounting in a small engine compartment. There is not much room at all, especially if it's AWD. You have to jump through your rear to get to the top of the transfer case once in the car.
Fun materials !!!!!! I am surprised at Beryllium, because its carcinigen. Whats Invar ?
Beryllium was the material of choice for buckling-critical structures before graphite became mainstream (yeah, I'm dating myself). The carcinogenic issue can be dealt with. The real problem is that it's very notch-sensitive. You can't drill holes in it, you have to chemically mill the holes. There's a story about how a few techs trashed a completely assembled beryllium structure for a DoD satellite when they tried to lift it without taking all the bolts out first.
Invar is a high temp nickel-iron alloy with very low CTE.
Invar is a high temp nickel-iron alloy with very low CTE.
Invar is used frequently in the composite industry for bond form tooling. Thermal expansion (CTE) is nearly identical to carbon fiber which greatly simplifies the amount of calculations the tooling guys need to program their CNC tapes during the tool fab machining process.
Invar is used frequently in the composite industry for bond form tooling. Thermal expansion (CTE) is nearly identical to carbon fiber which greatly simplifies the amount of calculations the tooling guys need to program their CNC tapes during the tool fab machining process.
Yup. Done that also. There are also companies who make composite tooling that is post-cured to allow use at temperature in autoclaves. It's only good for short runs, but in the space business three copies is "high rate production". Much cheaper than Invar.
Invar is used frequently in the composite industry for bond form tooling. Thermal expansion (CTE) is nearly identical to carbon fiber which greatly simplifies the amount of calculations the tooling guys need to program their CNC tapes during the tool fab machining process.
Is this from Wikipedia ? In the early days (1960-70's) NC controls used paper tapes. That has been replaced with CNC (Computer Numerical Control) which is digital. CNC can compensate for these previous "calculations" very easily.
Originally Posted by joe_padavano
Yup. Done that also. There are also companies who make composite tooling that is post-cured to allow use at temperature in autoclaves. It's only good for short runs, but in the space business three copies is "high rate production". Much cheaper than Invar.
INVAR has a very high Nickel content. The difference I noticed was it doesn't have any appreciable amount of Chrome, compared to Stainless Steels. It would be difficult to machine,drill and tap threads.
I checked online and a 5/8" diameter rod was $168 per foot.
For what it's worth, Vespel is being used in automotive applications but, as stated, it is expensive - mostly because it can't be molded like a typical 'plastic' and must be machined. I've personally applied it to a few very common applications I would guess many of you drive. PEEK (some grades) is a decent alternative which is used more often. Not as top shelf as Vespel but can be molded into shapes which makes it preferable, assuming it can survive.
I'm done.
For what it's worth, Vespel is being used in automotive applications but, as stated, it is expensive - mostly because it can't be molded like a typical 'plastic' and must be machined. I've personally applied it to a few very common applications I would guess many of you drive. PEEK (some grades) is a decent alternative which is used more often. Not as top shelf as Vespel but can be molded into shapes which makes it preferable, assuming it can survive.
I'm done.
That's good info. One of the continual pushes in the aerospace industry is an attempt to look for automotive industry solutions that give us 90% of the capability for 50% of the cost, or something like that. There are times when you have no choice and just bite the bullet because the high cost solution is the only one that works, but there are a lot of cases where people in one industry just don't know about solutions developed in another. Of course, there's a big difference between buying five parts and 50,000.
Is this from Wikipedia ? In the early days (1960-70's) NC controls used paper tapes. That has been replaced with CNC (Computer Numerical Control) which is digital. CNC can compensate for these previous "calculations" very easily.
Not from Wikipedia. When you are building large bondform tools (think large aircraft Fuselage,Wing or Control Surface components), you want to eliminate all variables that are economically possible. Yes that much INVAR will cost a lot of money, but these tools will cycle an almost infinite number of times without developing leaks.
Last edited by 4+4+2=10; May 13th, 2021 at 06:30 PM.
May 9th, 2021, 08:17 AM
