Hey everyone I just gutted 2 of my cats and I tested to see if my 5th and 6th were opening and there not.. Whats the hp loss on something like that... It felt like I gained quite a bit and I didnt notice a loss at higher rpms so what would the hp and tq loss be like. Thanks for the help.

 

How did you test? Which cats did you gutt?


Santiago

 

Well since they arent opening you should use your airpump and an air valve to make them open, that is if you still have your airpump. If not, you should wire them open at all times.

Running with those closed all the time will cause a drastic loss in top end power.

 

Well as long as your main cat is not gutted they probably should work anyways since the fitting that goes to the ports is on the split ait tube/pipe and that is where the pressure comes from to open them. If you gutted it you probably will have to find another way to operate them. I don't suggest you wire them open permanently since this is not the BEST thing to do: https://www.rx7club.com/forum/showth...tterfly+system
You could find an alternate way to operate the auxilary ports, via an electric air pump for example. Later on you can get a pre-silencer or a high-flow cat for them to work properly.


Another possability is that they are stuck shut. In this case you can clean them up and make sure they move freely in their slots. This will make sure they don't stick.


Santiago

 

I gutted the last two cats I was told that my air pump didnt control my accuators because its an 88. I have no air pump on it now. To test them I put grease on the rods and took it for a run getting above 3800 a few times brought it home and the grease hadnt budged. I'm replacing the 2 cats with a high flow cat hope that will help a little. I havent noticed a loss in power and felt a bit of a gain from my gutted cats. I raced a prelude and did fairly well ending with my front bumper to his rear. I heard preludes are pretty fast so I figured it was doing good.

 

Ludes arn't fast!!!


Whats wrong with your car???

I am 80% sure that the Bonez hi-flow cat will have the fitting on it to control the ports. IF you don't have emmissions to deal with you can get the RB pre-silencer with the H-fitting on it to operate the ports.

Santiago

 

Oh but the all might non-turbo RX-7s are Gods gift to speed. Any Lude from 94+ could kill an n/a stock for stock. I believe the 94 Ludes with VTEC run about a 15.4 1/4 mile.

If your ports arent opening, your motor is starved for air, if you think your car is fast now, get those working right.

 

That may be true but from what I have experienced on the street they are not fast.


What Lude did you race? year model? Vtect?

Santiago

 

98 prelude non vtec

 

I mean it was a vtec

 

right now my car has a vaccum leak and the ports arent opening. Its running stock for the most part except for a k&n filter and secondary throttle body plates removed.

 

contrary to what some people say they operate via the air pump. Mine were not opening due to the pump bracket being broken and the air hose popping off the ACV. My split air was still hooked up and they didn't function. I removed the air pump,"temporarally wired the 5&6 open as well as the VDI." The difference was huge. New car on the top. Idles a bit rich but who cares! Buy the gaskets for the IM to engine and the two extension gaskets and remove the valves.(6pi&VDI) Enjoy the new power!!!!!!

 

on Series 4 they are controlled by the main cat back pressure, and on series 5 they are electronically controlled.

best bet would be to get some pineapple sleeves and wire them open.

 

BigIslandSevens

S4 uses exhaust backpressure
S5 uses the air pump


Pay attention!!!

Santiago

 

And if they arent opening on S4s due to backpressure, you can use a manual air valve hooked up to your airpump to open the ports at whatever RPM you want. I did that for awhile, then I got sick of looking at the airpump and ACV...

 

BDoty311- YOu ever think about electrical operation of the ports? I think there are several threads on this.

BTW if you want to do it with the air pump they should open up at about 3800rpm.


Santiago

 

I did at one point, but when I had the motor apart I decided the actuators were restricitions in themselves, so they are gone.


3800rpm is what they open at from the factory, but for the best powerband, they should open around 3500rpms.

 

take the outlet pipe from the air pipe, split in a new line and silicone it up tight, run it over to the 5th/6th actuator input

i just did this (remember my thread about this same deal earlier, 1987rx7guy? )

anyways, they open up right on time, no problems now.

 

wasn't that like a year ago?


lol

 

Technically, there is no such thing as electrical operation of the ports. The actuators must have air pressure of some sort applied to them. The application of that pressure can be electronically controled, but you must still have some source of pressure, whether it's exhaust backpressure, the stock air pump or an electric air pump.

 

Well if you get to electrical motors that turn the little rods to open them that would be electrical way wouldn't it? Not to saw they would last long.

 

all hale mighty santiago. call me when you own your own shop deuchbag!!

 

Cant we all just get along. Thanks for help everyone.