Cold air intake methods

[Mike Rohaley]

My 2001 Caterham (Zetec VCT with F.I.) uses the "stock" method of picking up air from directly behind the engine (in front of the fresh-air heater). This may very well be in the absolute worst position to locate it and I am sure someone out there has found a better way, I am looking to fix this deficiency over the winter.

 

Question is: What is your solution to get some good cool air into your throttle body setup without cutting the bonnet up for some sort of scoop? Any photos to show off your workmanship would also be greatly appreciated.

 

Some background information: I have investigated modifying the glassfiber airbox to get air from the front of the engine (versus the rear) and relocating the coolant resevior to do so but found that the throttle mechanism intrudes greatly and would bottleneck the airflow around it too greatly. From there I am just stuck scratching my head looking for a better way. Thanks in advance.

[soareyes]

Mike, I recently fabricated an aluminum shroud that surrounds the air filter so that the only air source is through the hood louvers. Like your car, the air filter in my Birkin is located at the back of the engine comparment close to the firewall. I first made a cardboard mockup to use as a template, the reproduced it in aluminum sheet. I lined the edges of the shroud with foam so it seals against the hood. I haven't tested it yet on the road, and I was concerned that the hood louvers weren't large enough for good air flow, but it runs well in the garage! I'll try to take some photos to post when I get home.

 

 

[Dave W]

Cold Air Box

 

I made one from fiberglass, because it does not transfer engine bay heat as easily. Basically my cold air box seals up against the top of the nose cone Via foam and with the inlet above the Rad and to one side of the filler neck. I also added a little deflector in front of the rad to prevent any heated air from coming up off of the rad and into the inlet opening. The box is very light Wt, and is just held in place by one 6mm bolt and a quick release fast pin, which you not see in the photo.

http://www.usa7s.com/aspnetforum/upload/1997712066_lofrtopen.jpg

 

Dave W

 

[Al N.]

Mike, would you consider switching to individual throttle bodies? I've seen some guys (don't know what engine or ITB config) use them without cutting a hole in the bonnet.

[Birkin42]

That looks like a pretty nice setup Dave.

I was originally thinking of doing a flat filter in a custom air box for my S2K Birkin, but this looks like it will work well for me and should be a lot easier to make.

Using the roof of the nose cone for the top of the air box is a great idea.

Now to see if I have the vertical height for a round filter.

Can you let me know what make/model filter you are using and what its dimensions are?

Probably a good place to start.

 

Jack

[Mike Rohaley]

soareyes: That was one option but I was a bit concerned with two issues actually. First is the potential lack of airflow and secondly, the rain water issue since I use the car rain of shine. A drain hole at the bottom of the box may work great and not add a measurable amount of heat to the air temp though. And yes, I would love to see what you have done.

 

Dave W: What you have done is exactly what I wanted to do. What intake system is that on your car? My car uses the stock Ford long intake plastic runners which mounts the throttle body horizontally and does not give enough physical space to run it that way. However, Christine Fox who races a Caterham in SCCA E-Production showed me a couple years ago that she was able to do it using a specially modified radiator and some silicone hoses. The cost of the custom radiator was my only major problem at that time which kept me from persuing that route. Your solution looks to be about as good as it gets.

 

Al: Right now I am a bit weary about starting down that downward spiral of changing out intake parts of that sort. Doing that will no doubt lead me to a stand alone ECU and a ton of dyno time to dial it in (hopefully). And from what I have read (High Performance Ford Focus Builders Handbook) you will not see a noticable gain on the dyno until you reach 175 wheel HP or more with intake mods (that test was between a stock Zetec and a FocusSport 65mm throttle body). According to the book, I will see much more performace for the dollar if I can increase flow in the cylinder head itself which is why I am focusing (pun) my attention for more HP on that. I have a cylinder head at home that I will be (someday) porting myself, then it will be decked by about .030" and topped off with some mild cams to gain a hopefull 35HP. The desire to decrease my intake temperature is one of those relatively simple solutions that should be done first if I am really serious about making power.

[Al N.]

Mike...I forgot that in some configs you can use the stock ECU and not the Pectel T2 I wrestle with....

 

[CLARIFICATION: I was talking about non ITB configs...:cry: Sorry.]

[Mike Rohaley]

That is promising. I live in an E-Check area which means that I need to be careful with any modifications that I make to the car, no matter what they end up being. Either that or I will need to switch the car back to stock once every two years. Not only would that be a pain in the butt but it is not exactly legal.

[Mike Rohaley]

Come to think of it, the roller-barrel intakes on Frank's CSR are reallllly cool. Maybe I can convince Jen that I absolutely MUST change them out this winter.

[Boxologist]

i hope to attempt to build a new air intake path for my zetec this winter Mike. same setup as yours, zetec with stock air plenum and accordian hose to the rear with stock ECU. I wish to make it similar to dave w's. I will take the shape of the lopsided piece that sites on the throttle plate and have some sort of tube that comes forward and takes air from above teh radiator. i will end up putting a spliter on teh top of eeh radiator with a edge that stick forward a few inches to make sure the air is divererted and then get moved to an air box housing the cone filter.

 

the air box's shape will shrink towards its rear. i eventually hope to have a nose cone thats setup like the CSR that will allow air to be diverted from right after the radiator to leave above the car instead of underneath or get trapped in the hot engine bay.

 

the biggest pickup in power is just getting the better ECU in there and tuned.

[Mike Rohaley]

Refering to :the biggest pickup in power is just getting the better ECU in there and tuned.

 

What sort of gains could I expect with a switch to another system? I would have assumed that the factory programming would be pretty close to optimized for most situations. Unless Ford is undertuning the engine by more than about 20% I would have a tough time ponying up a grand or more for only a 10 HP gain at an RPM that I may rarely visit. Keep in mind that I know very little about fuel mapping and spark curves, my knowledge on the subject is based on superstition and stories passed down from town elders (spooky stuff to me).

 

[Boxologist]

its not that ford is undertuning our setup. Ford never tuned for our setup. they tuned for the intake and paper filter, a tranverse drivetrain, and at least a different catalytic converter, if not 2, plus a muffler and resonater.

 

thats nothing what caterham drivetrain looks like, and i have a mild setup. Snake Bit is louder than many cars on the road, but se7en owners question whether the engine is actually running!

 

I think someone actually dyno'd a zx1 or 2 zetec setup as it comes from CatUSA and it barely broke 100rwhp on a manufacturers rating of 147chp. with a less restrictive exhaust like we have and a more efficient drivetrain we should be seeing more power to the wheels than a focus or contour stock, not less.

 

So i think there is some fuel mapping to be revamped, and once the Air Intake Temperature situation can be straightened out, I think much power can be reclaimed.

 

how much? 20+ peak rwhp on the conservative side. possibly manufacturer's crank claim at the wheels from a good tuner.

 

thats without playing with the valve size, crank duration, or porting. or a better flywheel.

 

unfortunately i only plan to go as far as intake in the next year, and EM the year following.

[JohnK]

Mike,

If you're using the configuration that I'm familiar with - throttle body sticking straight up on a plastic inlet manifold, I was able to fit a reasonable inlet system on the Superformance S1 running a Focus ZX3 sourced Zetec. I found that with a rubber doughnut adapter, the inlet boot from a 1987 VW Golf provided a very nice connection. It gives you a right angle redirection to the airflow, is very low in profile, and incorporates a plenum so that it breaths well. This, with a hose clamp holding it and the doughnut-spacer - maybe 3/4" thick flat neoprene - to the throttle body was quite secure. Given this you can run a connecting tube forward toward the nose of the car and attach an airfilter. I was able to use the stock Focus (ca. 2000) air tube with minor modifications. The last part would be to pick up a cold air stream from the front of the car, and of course finding room to put a box or baffle of some sort to do the directing of the airflow. The S1 took air that came in over the top of the radiator (notice the large nose on an S1 with respect to a Caterham) and used a door that fell down in font of the radiator a little when the car was stopped so that the engine wasn't inhaling hot air rising off the radiator. Hope this helps.

Cheers,

 

[JohnK]

Mike,

With respect to getting more power. To the best of my knowledge, the Ford system is unlike any other system out there. All the other systems run off calibration tables that fit a set of pieces (air filter, exhaust system, ...) If you change any of the engine fittings, the table(s) will be out of synch and the car will run worse. The Ford system is adaptive - it doesn't use tables, it runs an algorithm that figures out how much fuel to deliver and when to fire the spark for each cylinder each time each cylinder fires. It does this by weighing the air that the engine is bringing in and then looking at RPM, throttle position, throttle change, air temperature, and so on. As long as the things that the computer is listening to (like the Mass Air Flow sensor which weighs the air) and the things that the computer is talking to (like the injectors) are IDENTICAL to the system as it was originally put together, Things will work well. Not a fire breather, but you should see very very good DRIVABILITY, meaning throttle is always there, it starts and idles when it's 15 degrees or 105, it gets good economy, it even has the equivalent of a passing gear - making more power when you step on the gas quickly and a lot. This requires that everything is as it should be with respect to the configuration of sensors and effectors. If something's been switched or is operating poorly (the MAF can be a deadly player here), the computer will be doing it's calculations based on bad information. However you CAN run an efficient air filter, same with the exhaust, and actually get more power. You can even have the head ported and polished and get more power. The limit is the size ofthe injectors - they can only deliver so much fuel, and when they're maxed out, that's all you get.

You can buy aftermarket setups and get more power - this is possible. However, all of my experience is that this nearly always leads to something that runs, overall, poorly and is very expensive and is very very disappointing. Huge numbers of people out there really BELIEVE that tuning just isn't that difficult, but then there are also people who BELIEVE that the Earth is flat. If you want power, buy an engine from an estabilshed company whose business is building engines and who have a reputation and who charge an arm an a leg.

One footnote. Years ago a guy named Erick Goel reverse engineered the code in a Ford Mustang ECU and made a board that plugs into the back for the ECU and a software interface for the user. Using this, the owner can, say, install larger injectors and a larger MAF ( more fuel available, better breathing) then go into the computer, update the value of the injectors and the table that translates the output of the MAF into kg or air per minute, download the changes to the ECU, turn the key and the car will start and run not only better, but be drivable as well. This, in my mind is amazingly cool - and I don't think that there's anyone else out there besides Ford who has done this. All the other system require huge amounts of time to get their engines to run well.

Cheers

[Mike Rohaley]

Thanks John, I appreciate your insight. Also, I am going to give your VW solution a shot. It sounds perfect.

[soareyes]

Mike, here are the photos of my air box (not the best quality but it's dark out there!), The foam is temporarily attached till I get the thickness right. The box butts up against the hood and air would feed through two banks of louvers in the hood. I had calculated the square inches of total opening, but can't remember it now. However, it was larger than the air intake on my 225 hp sedan, so I'm hoping it is enough.

 

Without:

 

http://www.usa7s.com/aspnetforum/upload/380080417_DSCN2892.jpg

 

With:

 

 

http://www.usa7s.com/aspnetforum/upload/1406741886_DSCN2897.jpg

 

 

 

[Mike Rohaley]

Nice Stan, is the 90 degree rubber-looking piece a stock Birkin part? Mimicking your box and maybe (just maybe) adding a NACA duct on the side of the bonnet instead of injesting the pouring rain would work nicely.

 

Actually, that brings up yet another question: Do you guys who run exposed Webers have any issues with water injestion or is it a positive in that it helps to cool the fuel charge? I may very well be worrying about a problem that doesn't even exist.

 

FYI I did some digging and found a few pictures of Christine's plumbing work. Notice the adjustments required to the radiator to get some airflow above because the stock unit runs too close to the underside of the nosecone to allow a simpler method. That and the relocation of the overflow resevoir.

 

http://usa7s.com/aspnetforum/upload/669719728_BeaveRun 6-17-06 001.jpg

 

http://usa7s.com/aspnetforum/upload/579792031_BeaveRun 6-17-06 002.jpg

 

http://usa7s.com/aspnetforum/upload/745088347_BeaveRun 6-17-06 003.jpg

 

http://usa7s.com/aspnetforum/upload/1489121174_BeaveRun 6-17-06 004.jpg

[Mike Rohaley]

Speaking of rain issues

 

http://usa7s.com/aspnetforum/upload/1374788864_eleven in the rain.jpg

[soareyes]

Nice Stan, is the 90 degree rubber-looking piece a stock Birkin part?

 

Yes, I believe it is as I've seen it on several other Birkins.

 

 

 

[slomove]

Do you guys who run exposed Webers have any issues with water injestion or is it a positive in that it helps to cool the fuel charge? I may very well be worrying about a problem that doesn't even exist.

 

Nah, I don't think that is an issue (at least with throttle bodies or Webers). As long as you don't empty a bucket over the intake while running....The few rain drops that hit the filter are insignificant compared to the consumed air volume.

I drive rarely in the rain but the few times I did (sometimes heavy) there was no difference. Even starting after the rain soaked my ITG foam filters overnight was not a problem. The way the filters are mounted, water won't run directly into the trumpets anyway and drip out of the bottom.

 

Gert