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

performance problems

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Old Jun 21, 2003 | 01:22 PM
  #1  
Terrh's Avatar
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performance problems

I hit fuel cut today.. about 3 times
So I KNOW that the car is boosting properly. Anyone else do that with just gutted cats?

I obviously need an FCD now.. I shouldn't be overboosting serioulsy enough to need more fuel, right? I've got totally stock exhaust + smaller than stock mufflers + gutted cats
I'm probably going to get some different mufflers in the near future, though. I don't think that will effect boost much?


Anyways.. even though its boosting properly and driving well and etc and etc... it still feels slower than it should be. Now that it hits fuel cut (amazing what decent gas can do for a car) I can't really test anything until I get an FCD... but anyone have any ideas here?
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Old Jun 21, 2003 | 02:49 PM
  #2  
Icemark's Avatar
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From: Rohnert Park CA
get FCD and go from there if there is still a problem.

Muffler size won't make much difference after you have already removed the cats. The cats are the biggest restriction.
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Old Jun 21, 2003 | 08:20 PM
  #3  
600HP CLUB's Avatar
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i had boost cut with stock exhaust and dirty stock intake, just gutted cats. Try adding a restrictor in-line to pressure sensor vac line.
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Old Jun 21, 2003 | 08:29 PM
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Stop messing around. Get an FCD, and get a real boost gauge. If you don't think the car has the power it should put it on the dyno and find out.

Do you still have the stock twin scroll setup? The twin scroll on my car would stick and the car would make full boost but go nowhere.
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Old Jun 21, 2003 | 09:27 PM
  #5  
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Yeah, I still have the twin scroll.

Guess what's next on my removal list?
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Old Jun 21, 2003 | 09:30 PM
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I second that. You really need a "real" boost guage if you don't have one already. Be careful with the FCD, as it will fool the ECU and you will get LESS fuel as your boost passes the 8.6 PSI cutoff. Best to get an A/F guage for at least some sort of warning, and upgrading the fuel pump wouldn't hurt.
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Old Jun 21, 2003 | 10:20 PM
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hitting fuel cut is not good, don't do it anymore.

When your twin scroll was sticking was it staying closed, or open?
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Old Jun 21, 2003 | 10:30 PM
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Knowing you, your timing will be spot on... but an overly retarded timing will cause you to be slower than you should be
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Old Jun 21, 2003 | 10:33 PM
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I'm going to get an EGT gauge and a boost gauge as soon as I can.

I know that the FCD will trick the ECU and make it run leaner, but if all I have is a gutted exhaust + stock pipes, then there shouldn't be much problem with running lean, fuel cut is 8.6 PSI and it's probably running like 8.62...
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Old Jun 22, 2003 | 11:01 AM
  #10  
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Originally posted by rotary>piston
hitting fuel cut is not good, don't do it anymore.

When your twin scroll was sticking was it staying closed, or open?
Hmm good question, I guess if it was making boost but not gaining any power that would make it stuck closed. I actually think it was the selenoid rather than the door or the actuator that was malfunctioning.

I know more than a few people who use a WB O2 sensor as opposed to an EGT. The EGT reacts to slowly and really gives you NO indication of your A/F ratio when you need it. Oh and Terrh there have been more than a couple motor's blow on the the stance your taking, "All I did was gut my cats, now I hit fuel cut, but I should be OK" You're asking for trouble. Take a lesson from many forum members before you. Do things right the first time. Fuel mods, fuel mods, fuel mods, or LEAVE IT STOCK.
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