my results
Thread Starter
Instructor
Joined: Apr 2013
Posts: 178
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my results
I have an 88 coupe auto. It has 50k miles. Shift kit , open air filter cover , removed pie plate, magna flow exhaust with no cats and factory manifolds. What horsepower and 1/4mile time could be expected if I decided to do the above combo?
Team Owner
Joined: Oct 2007
Posts: 26,745
Likes: 694
From: PA
You dont have full exhaust. Factory manifolds are the bottle neck. Cat backs save weight and give sound. Without manifolds being swapped you won't make more power. Simple as that.
Get some long tubes and tuned and you will make more power.
Get some long tubes and tuned and you will make more power.
Thread Starter
Instructor
Joined: Apr 2013
Posts: 178
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I thought removing the cats gave more power?
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
A few hp at best youll never feel it unless they are plugged up currently
If its something you were going to do anyway ie "every bit helps" go for it but to spend the money hoping for big power gains nope
Times will depend on state of tune, D.A. your driving tires lots of things. My first couple times out I was running 15s.
If its something you were going to do anyway ie "every bit helps" go for it but to spend the money hoping for big power gains nope
Times will depend on state of tune, D.A. your driving tires lots of things. My first couple times out I was running 15s.
Last edited by cv67; Aug 14, 2015 at 11:58 PM.
Team Owner
Joined: Oct 2007
Posts: 26,745
Likes: 694
From: PA
Changing all but the biggest bottleneck won't net much and only a fraction of the potential power.
Pretty much, in this case.
In higher HP applications the cats are more of a HP robber than in this instance.
In higher HP applications the cats are more of a HP robber than in this instance.
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
When my 91 was stock it ran 14.0x at 99 or so. With exhaust mods similar to your's (front y-pipe w/out cats, hollowed main cat and aftermarket cat-back) it went 13.80 or so. Its been quite a few years, but IIRC deleting the cats was the biggest gain although, as others stated, I can't say for sure if this was due to my cats being clogged.
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Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 113
From: Michigan
Stock manifolds are fine for a stockish-mild engine, people over header c4's a lot! Until you make over 400hp I wouldn't even think of 1 3/4 headers. If you look at the stock racing classes some of those guys that really fine tune those best stock parts you'll see they got a 1 1/2 primary and making around 350-375hp.
Team Owner
Joined: Oct 2007
Posts: 26,745
Likes: 694
From: PA
When my 91 was stock it ran 14.0x at 99 or so. With exhaust mods similar to your's (front y-pipe w/out cats, hollowed main cat and aftermarket cat-back) it went 13.80 or so. Its been quite a few years, but IIRC deleting the cats was the biggest gain although, as others stated, I can't say for sure if this was due to my cats being clogged.
Without seeing a slip, the ET to me doesn't mean much. If its all in the 60 foot, its due to hooking better.
Sounds like you had a strong L98.
