2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Stock manifold to straight pipe then stock muffs?

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Old Aug 16, 2007 | 11:38 PM
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Stock manifold to straight pipe then stock muffs?

I've been looking at the RacingBeat test pipe with the silencer, and a few people since I've been on this site have suggested it. I don't have the funding at the moment. This car is a daily, ( so I can save for motor parts on my truck) Anywho, If I hack off the cats on my FC can I just weld in a straight pipe to the y-pipe? With the stock mufflers will it still be resonably quite? I'm not familiar with how loud the roatarys can be so I'm curious. I can weld in a straight pipe for the cost of 1 hour of time not going to the couch lol.
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Old Aug 17, 2007 | 12:07 AM
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itll be loud as all hell and your 5th and 6th ports wont work.

if its a daily just leave it alone.
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Old Aug 17, 2007 | 12:28 AM
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From: Austin Tx.
ok That's what I figured...

What can I do to this thing just to perk it up a bit. Any intakes or ignitions help? I'm going to run the fuel injection drip line thingy ma bitch through it tomorrow cause it's idling rough...

Also I'm going to check the compression, what's average for an N/A FC with 77k on her?
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Old Aug 17, 2007 | 12:57 AM
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Should be at lest 95psi or higher. What year? Pics? If you have an S5, you won't need to worry about the 5th and 6th ports as they are opened by the airpump. If you have an S5 and no airpump/disconnected airpump, that would be a good place to give it some pep. Build a cold air box with a cone filter can't hurt either. But if you want to give it any type of decent power you need a full exhaust which is pricey so I'd just leave it be until you get the motor done in the truck
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Old Aug 17, 2007 | 01:06 AM
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From: the nati, ohio
a full tune up

and make sure the 5th and 6th ports work.

ive owned 3 different na's and none of them ever had the ports work.

now i got them working with this car, and the difference is night and day. theres power everywhere instead of having to choose between power down low and nothing up top or power up top and nothing down low.
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Old Aug 17, 2007 | 01:55 AM
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i had hollowed out cats going to an HKS catback, which is somewhat like stock. it was pretty loud. i kinda liked the tone tho.
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Old Aug 17, 2007 | 08:40 AM
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with the stock manifold and stock mufflers (assuming they are in good condition) that is not going to be that loud.

i have done a lot of experimentation with my exhaust system. to date i have had FOUR different setups on my car within the last 4 years.
i have tried what you are describing, stock manifold -> straight pipe -> y-pipe -> stock mufflers, and sound-wise i actually think it is the second best i have had on the car. it's not too loud, especially compared to any system with headers....
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Old Aug 17, 2007 | 09:29 AM
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hollowed cat and stock mufflers
as long as your mufflers arent blown, they would be resonable/
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Old Aug 17, 2007 | 10:26 AM
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From: Austin Tx.
How do I tell if my ports are workin and or telling if it is an S5.

It's a 90 N/A GXL, and I do have a smog/air pump on it.
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Old Aug 17, 2007 | 10:33 AM
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man that would sound awful
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Old Aug 17, 2007 | 01:26 PM
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quick question, if you have aftermarket headers and then get a straight pipe yet still have your stock y-pipe and mufflers...the 5/6 ports will work with no problems right?
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Old Aug 17, 2007 | 01:47 PM
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Originally Posted by andersonvann
quick question, if you have aftermarket headers and then get a straight pipe yet still have your stock y-pipe and mufflers...the 5/6 ports will work with no problems right?
If it's an S4 some part of the exhaust system needs to provide back pressure for the ports to work. This either comes from the Cat or the header depending on what parts have been installed/removed from your car.

If it's an S5 it just needs the air-pump for that.
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Old Aug 17, 2007 | 03:01 PM
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From: eureka
Originally Posted by VortecBowtie
How do I tell if my ports are workin and or telling if it is an S5.

It's a 90 N/A GXL, and I do have a smog/air pump on it.
86-88 s4
89-92 s5

Go ahead and do it. A little louder but thats what you want. Save the cats so you can pass smog if needed.

Also do the intake elbow mod + CAI

To make a simple CAI just buy a throttle body adapter $15 drill holes to fit. Use stock gasket. Then buy a cone filter.
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Old Aug 17, 2007 | 03:20 PM
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Do not build a CAI. Use the stock intake.

In order to get cold air to your "cold air intake" you need to make it at least as complicated and restrictive as the stock system.

In order to keep it simple, you basically have to use hot engine bay air.

Since the stock intake is NOT a restriction (don't let anyone lie to you... it isn't) and does draw cold air, it is for the win.
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Old Aug 17, 2007 | 03:25 PM
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If you cant afford it leave it alone.
I put the racing beat header, Presilencer and catback system on it. It sounds great.
Wait until you can afford this. This boosts up Horse power also.
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Old Aug 17, 2007 | 04:17 PM
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Originally Posted by VortecBowtie
How do I tell if my ports are workin and or telling if it is an S5.

It's a 90 N/A GXL, and I do have a smog/air pump on it.
You have a S5.
Here is a shot of the 5th & 6th ports (actuators removed)...

(photo by RotaryResurrection demonstrating his powder coating prowess-see the 2nd gen Classifieds for details)

The actuators are mushroom shaped with a rod coming out the top that connects to the crank arm on the port sleeve. They attach to the studs you see next to the sleeves.
To verify operation just put a little grease on the actuator rod and go drive the car.
Take her up to redline under load a few times.
Now check the rods and see if the grease has been displaced.
If so, the ports are working.

Congratulations on surviving the trip, BTW.
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Old Aug 17, 2007 | 06:42 PM
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just take the rods out then cover the hole, A dime fits perfectly in the hole, with a ledge. so a little JB weld and some time and it works fine

if you wanna remove your 5/6th ports remove everything, even the port sleeves.


IF you are removing your 5/6th ports.
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Old Aug 17, 2007 | 08:04 PM
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From: Austin Tx.
/\ Why would I want to remove them?????
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Old Aug 17, 2007 | 09:13 PM
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From: eureka
Originally Posted by kontakt
Do not build a CAI. Use the stock intake.

In order to get cold air to your "cold air intake" you need to make it at least as complicated and restrictive as the stock system.

In order to keep it simple, you basically have to use hot engine bay air.

Since the stock intake is NOT a restriction (don't let anyone lie to you... it isn't) and does draw cold air, it is for the win.
I respectfuly disagree! I put on a cone filter in the "HOT" bay and noticed a diffrence right away! The engine wanted to go the redline much quicker.

While the stock unit may suck colder air it does make the air twist and bend.

Which brings the ? up--- how come so many people use them?
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