90/91 Callaways - how does the air filter work?

[malc350]

Don't mean to sound stupid again but when I look at my air filter box I can't help thinking "how does it work?" I t looks like there is only one large hose running from the air filter box to the wonderbar. This can't be right? Where does the air filter take air in from? If I can find the right part in the UK I'll probably fit a cone type like UltraSlow has. I have to be real careful with the wires to the sidelights when I open the top of the box.

 

[SurfnSun]

Malc, the 87s and 91s take in air from the stock location over the radiator. 88-89 and 90(I assume the filter is by the pass headlight.) take air from that surrounding area.

Youre right though, the stock b2k airbox is constrictive. But it is due in part to wet driving conditions. When you go with the cone filter as many of us have, understand that any water that leaks around the headlight is going to land right on the filter.

 

[malc350]

Holy restriction batman

that makes me think the air filter box is more restrictive than the old wonderbar! Must have taken Callaway ages to work out all those little details.

Looks like I mistakenly assumed the 91 would have the same intake as the 90 as they have the same type of fuel injection. Wonder how good (and powerful) our cars would be if they kept developing them up to now (2004 Callaway Twin Turbo - cool!)

 

[SurfnSun]

yes between the airbox and original wonderbar, there is alot of hp to be freed up.

You should have seen what my car did to a stock filter after the Wonderbar upgrade. The suction thru the airbox was so strong it deformed and contorted a brand new air filter the same weekend after putting it on. I soon after dumped the airbox and put a cone filter on.

 

[malc350]

I'm wondering if the car was trying to draw more air than the air filter housing could flow in? I've a feeling the cone filter alone will make a difference. Just need to find one the right size over here. Shouldn't be too much of a problem though. I'm sure one of the local speed shops that sells stuff to the "fast 'n' furious" mob will have a generic filter that's the right diameter.

If I get a chance in the week (I hate jacking my 'vette up) I'm gonna have a good look underneath at this wonderbar situation.

 

[malc350]

Just realised another thing

I wondered how the air was getting in the box becuase I thought it was sealed. Looks like it takes the air in from the small opening in the back, with the flexible plastic flap over it - facing backwards too!

Added to that the flap half covers the intake hole, I can hardly believe my car is flowing any air!

If it wasn't a rare (expensive, no longer available?) part I'd cut the air box cover open like a lot of people do with the regular C4 air box.

Wow, this really is an area that needs improvement on these cars.

 

[SurfnSun]

Yes, too much air through not a big enough space. 89x2 has a long K&N cone on his, and I think he said it collapses a bit under boost

BTW the cone filter on my car was for a Honda, but it bolted up perfectly to the MAF sensor.

 

[malc350]

The other thing I'm thinking is

maybe I can make up a frame that follows the outline of the airbox so I can clamp the filter down. I'd keep the bottom part of the box but the top of the filter would be completely open resulting in a large area exposed to the air.

All I'd need to make is something for the rubber clamps to clamp down on to hold the air filter in place.

Whatever filter we run (even a cone type) the area we're taking intake air from is far from ideal when you consider that the stock C4's air hits the spoiler and is deflected into the air filter housing, effectively giving a "ram air" effect.

If it wasn't for the fact I always regret cutting up factory parts I'd also consider cutting away some of the radiator shroud next to the box so that maybe some of the incoming air hitting the spoiler and radiator would get to the intake area.

I think our cars could really benefit from ram air. I can't believe how restricted our cars' intakes are. Could be a whole lot more power on the way!

 

[SurfnSun]

Malc, actually you already have ram air comes from two T04B turbos.

Actually once you put on the cone filter you will have ample breathing room under there. While the turbos definitely pull alot of air thru, I doubt its enough to create a vacuum or air shortage in that "cove" under the headlight. IMO I dont' think its too bad of a place to pull from because the filter is quarantined from the rest of the engine bay, pulling slightly cooler air.

But there must have been some advantage to the front intake system since they went back to in in 1991.... probably in the forum of the coolest air possible and less cost since the stock airbox was utilized.

 

[turbocat]

Malc, actually you already have ram air comes from two T04B turbos.

Actually once you put on the cone filter you will have ample breathing room under there. While the turbos definitely pull alot of air thru, I doubt its enough to create a vacuum or air shortage in that "cove" under the headlight. IMO I dont' think its too bad of a place to pull from because the filter is quarantined from the rest of the engine bay, pulling slightly cooler air.

But there must have been some advantage to the front intake system since they went back to in in 1991.... probably in the forum of the coolest air possible and less cost since the stock airbox was utilized.

The only Callaway with TO4B turbos was the Sledgehammer. The Roto-master turbos in production Callaways are the size of a T3 turbo.

 

[SurfnSun]

Are you talking impeller or housing?

Everything Ive read said that 87s had the IHI turbos and 88+ received the T04Bs.

 

[turbocat]

Are you talking impeller or housing?

Everything Ive read said that 87s had the IHI turbos and 88+ received the T04Bs.

The inducer size(diameter of the opening in compressor housing) on a Roto-master is 1.98 inches. A TO4B is 2.32 inches. The TO4B compressor housing is about 1 Inch larger in diameter than a Roto-master. Go under your car and look at the inlet hose that clamps to your turbo. It's about 2.25 inches in diameter. The same hose on a TO4B is 2.75 inches.

 

[SurfnSun]

So then any water cooled T3 turbo could be used on a Callaway?

 

[turbocat]

So then any water cooled T3 turbo could be used on a Callaway?

Yes ,you could mount a T3 in the place of the roto-master but the turbine housing would require a new wastegate .Turbonetics could probably fix you up. A T3 would not flow much more than a roto-master though so performance would not be improved. I'm in the process of installing T3/T4 hybred turbos . They just barely fit in the space of the Roto-masters. They have a TO4E compressor housing and a T3k center section and turbine housing. Should be good for an extra 300hp or so.

 

[SurfnSun]

I have often wondered about the t3/t4 hybrid. Are you staying with water cooled?

Did you ever get your wastegate situation straightened out? Im sure you'll need the racegates if you bump an extra 300hp. Thats almost $900 in wastegates

 

[turbocat]

I have often wondered about the t3/t4 hybrid. Are you staying with water cooled?

Did you ever get your wastegate situation straightened out? Im sure you'll need the racegates if you bump an extra 300hp. Thats almost $900 in wastegates

The center section is almost identical to the center section of the rotomasters -so yes ,they will be water cooled. You are right- I have two racegates for the turbos.

 

[SurfnSun]

When can we expect to hear more??? My interest is peaked to say the least.

 

[turbocat]

When can we expect to hear more??? My interest is peaked to say the least.

What do you want to know?

 

[SurfnSun]

final results, difficulties of the swap etc.

 

[malc350]

Turbocat

It will be interested to see the turbos fitted especially as I have so little room on the starter side (solenoid +ve was shorting on the turbo and I had to grind the post down to stop it killing my starter.