Air Intake, Aftermarket
03-03-03, 03:21 PM
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Air Intake, Aftermarket
Please Help! I have a 1991 RX-7 convertible, 5 speed. I removed the entire stock airbox and intake hose, bought a big K&N filter for the main intake and two little ones for the two drawn off of the stock intake hose. The airpump was removed, no fiter needed there. The car ran terribly!! Bad cold, not at all warm. The stock aribox has some weird-*** dashpot in it that must be very important. I put the box back in to plug in the dashpot, it still ran like ****. Put the whole damn thing in, it runs great. Can anyone tell me how to make it run without the stock airbox??? I am trying to reduce weight primarily, I was hoping for a noise (more) and performance (more) gain. Also, does anyone know where to get a perfomance chip for this car?? Many thanks to all of you who try to help...
03-03-03, 03:26 PM
#2
ok I have a S4 and your car is a S5 but it should be the same thing except that you so not need the adapter like me. you remove the stock box by unbolting it from the AFM then you attach the cone filter. You can not run the car without the AFM which is what I think you did. I just bought a cheap 15 dollar generic cone filter and made a ghetto adapter but you do not need to fabricate or buy an adapter cuz you have a S5 car. as far as removing the air pump you will need to wire open your auxilary ports or else they will not work properly(at all rather).
03-03-03, 03:27 PM
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where in ct are you? it sounds like you took off the mass air flow sensor. if your close to fairfield county i can give u a hand. my email/aim is moxeysrx7s@aol.com
03-03-03, 03:46 PM
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Thanks for your input 1987RX7guy. The problem is definately not the air pump, the later models dont use it for port activation. I had mine off before the whole intake fiasco. I made a nice adapter for the big K&N, and bought 5/8" I.D. minis for the other two. I did a real professional job!! I am so pissed LOL!! The second poster may be right, I need to know how to get around that.....
03-03-03, 06:41 PM
#6
Originally posted by 1987RX7guy
Uh not to argue but the S5 cars are the only ones that use the air pump to activate the auxilary ports S5=89-91
S4 used exhaust backpressure S4=86-88
Uh not to argue but the S5 cars are the only ones that use the air pump to activate the auxilary ports S5=89-91
S4 used exhaust backpressure S4=86-88
I was under the impression the S5 aux ports were electrically actuated...
Hmm...
Jarrett
03-03-03, 06:56 PM
#7
Yeah, everything that I have heard says the s5 airpump controls the 5th and 6th ports.
In the s5 the afm is actually somewhat integrated into the air box. They can be separated, it's just a couple more bolts. You have to have the AFM hooked up or the ecu has no idea what is going on. I'm quite suprised it would start without it. It has a little cone in it that gets pushed back when air is flowing through. the position of this cone thingy in the AFM tells the ECU how much air is coming in and it responds accordingly.
In the s5 the afm is actually somewhat integrated into the air box. They can be separated, it's just a couple more bolts. You have to have the AFM hooked up or the ecu has no idea what is going on. I'm quite suprised it would start without it. It has a little cone in it that gets pushed back when air is flowing through. the position of this cone thingy in the AFM tells the ECU how much air is coming in and it responds accordingly.
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03-03-03, 08:18 PM
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I feel like a newbie. If it has a carburator and a distributor and 8 cylinders I know everything. This EFI stuff isnt anything I have messed with before....
Okay, after reading all of the threads I think I have some idea how this thing works. The Bullet in the intake opens according to the amount of airflow, and the EFI reads the position and sets accordingly. By having it completely out of the car the EFI didnt get a signal and didnt know what to do. Plugging it in without airflow made the EFI think that there was no airflow at all so it didnt work either....
SO somehow I have to integrate the MAF into my aftermarket intake system right? I wanted to get rid of that thing because I thought it was restrictive. It is going to be a huge pain in the *** to do that! Right now I have the cone filter right on the intake.
Okay, after reading all of the threads I think I have some idea how this thing works. The Bullet in the intake opens according to the amount of airflow, and the EFI reads the position and sets accordingly. By having it completely out of the car the EFI didnt get a signal and didnt know what to do. Plugging it in without airflow made the EFI think that there was no airflow at all so it didnt work either....
SO somehow I have to integrate the MAF into my aftermarket intake system right? I wanted to get rid of that thing because I thought it was restrictive. It is going to be a huge pain in the *** to do that! Right now I have the cone filter right on the intake.
03-03-03, 08:23 PM
#9
Originally posted by skyypilot
Okay, after reading all of the threads I think I have some idea how this thing works. The Bullet in the intake opens according to the amount of airflow, and the EFI reads the position and sets accordingly. By having it completely out of the car the EFI didnt get a signal and didnt know what to do. Plugging it in without airflow made the EFI think that there was no airflow at all so it didnt work either....
SO somehow I have to integrate the MAF into my aftermarket intake system right? I wanted to get rid of that thing because I thought it was restrictive. It is going to be a huge pain in the *** to do that! Right now I have the cone filter right on the intake.
Okay, after reading all of the threads I think I have some idea how this thing works. The Bullet in the intake opens according to the amount of airflow, and the EFI reads the position and sets accordingly. By having it completely out of the car the EFI didnt get a signal and didnt know what to do. Plugging it in without airflow made the EFI think that there was no airflow at all so it didnt work either....
SO somehow I have to integrate the MAF into my aftermarket intake system right? I wanted to get rid of that thing because I thought it was restrictive. It is going to be a huge pain in the *** to do that! Right now I have the cone filter right on the intake.
03-03-03, 08:38 PM
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Thanks Mr. 13bpower...
My air pump does not work. When I removed the line feeding the cat there was nothing coming out of the hose. Wanting to save weight, I took it out. I have not road tested, but with the whole shitbox intake on it it runs perfect in the driveway. The roads are a mess so I cant roadtest yet, This car never sees rain, sno, or a dirty road...
This car has always had a flatspot from 4,500-5,000 RPMs. At 5,000 it hits like a turbo and the car pulls hard. Could this be due to the weak or non-functioning air pump? I was told the ports on this car were electrically actuated, but two of you say it is the airpump. One road test ought to settle it, but it could be weeks before I can do that.
Also, the car had ALL trailing plugs in it when I got it. It ran fine except for the flat spot. What would you have expected from that?
My air pump does not work. When I removed the line feeding the cat there was nothing coming out of the hose. Wanting to save weight, I took it out. I have not road tested, but with the whole shitbox intake on it it runs perfect in the driveway. The roads are a mess so I cant roadtest yet, This car never sees rain, sno, or a dirty road...
This car has always had a flatspot from 4,500-5,000 RPMs. At 5,000 it hits like a turbo and the car pulls hard. Could this be due to the weak or non-functioning air pump? I was told the ports on this car were electrically actuated, but two of you say it is the airpump. One road test ought to settle it, but it could be weeks before I can do that.
Also, the car had ALL trailing plugs in it when I got it. It ran fine except for the flat spot. What would you have expected from that?
03-03-03, 08:50 PM
#11
The air pump supplies the air, the ECU controls a solenoid that lets the air in. That's basically how the Auxilary ports are opened.
That "turbo" effect you feel at around 5000 RPM is the Variable Dynamic Effect Intake, or VDI. Your air pump must be working, because the air pump supplies the air for the VDI valve to open as well.
That "turbo" effect you feel at around 5000 RPM is the Variable Dynamic Effect Intake, or VDI. Your air pump must be working, because the air pump supplies the air for the VDI valve to open as well.
Last edited by JerryLH3; 03-03-03 at 08:53 PM.
03-03-03, 11:00 PM
#13
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The air pump does supply for the 5th/6th ports as well as the VDI. There has not been anyone that has made the 5th/6th ports work reliably with electric port actuation.
Since he describes the VDI operating with the comment:
I doubt the air pump was not functioning. It was probably just fine. It only pumps to the cat at specific throttle positions and gears.
Anyway, well untill he removed it and the AFM (as a hint, most of the stuff on the car is needed for emissions and power, so just ripping things off like the AFM or air pump is.. well not a smart approach).
Since he describes the VDI operating with the comment:
At 5,000 it hits like a turbo and the car pulls hard.
Anyway, well untill he removed it and the AFM (as a hint, most of the stuff on the car is needed for emissions and power, so just ripping things off like the AFM or air pump is.. well not a smart approach).
03-04-03, 11:43 AM
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This is the first car I have owned that removing the air pump was significant to the operation of the car. In most cars, the worst thing that happens is you cook the cat. Since the car had no cat, I didnt think it would matter. AND absolutely no air comes out of the hose to the cat at any throttle setting.
As far as the AFM is concerned, I had no idea what is was. My shop manual did not call it out anywhere. It looked like a major restriction and since I could mount the cone right to the throttle body adapter, I did. I have owned more cars than I can count, and rebuilt and hot-rodded most of them. I restored my first car when I was 13, bumper to bumper, every nut, every bolt. They were all "Old School", now I find myself back in school.... Most of the "teachers" here are very gracious.
You live, you learn.
As far as the AFM is concerned, I had no idea what is was. My shop manual did not call it out anywhere. It looked like a major restriction and since I could mount the cone right to the throttle body adapter, I did. I have owned more cars than I can count, and rebuilt and hot-rodded most of them. I restored my first car when I was 13, bumper to bumper, every nut, every bolt. They were all "Old School", now I find myself back in school.... Most of the "teachers" here are very gracious.
You live, you learn.
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