1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

gslse performance question?

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Old Jan 22, 2004 | 11:35 PM
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gslse performance question?

I just bought an 85 gslse, and i still own an 85 12A S. The 12A is straight piped and the nikki carb is tweaked a bit to deliver more performance. The 12A rips up to 7500rpm with ease. The 13B deffinitally has more lower end performance than my 12A but after about 5000 rpm it seems to level off a lot, if not get weaker. I've gutted the cats on the gslse, thinking they could be clogged, but the power delivery did not change. Really, i guess my question is...Is it normal for a gslse to not have that much high end power in stock form, and how can i fix this? The intake manifold is clean, and there is a new air filter also.
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Old Jan 23, 2004 | 12:42 AM
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you shouldnt gutted the cats because you need backpressure of the exhaust to operate the sleeves on the intake, and probably too that they are stuck close.
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Old Jan 23, 2004 | 12:42 AM
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Any help here?
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Old Jan 23, 2004 | 12:46 AM
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The sleeve worked right before eddierotary.
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Old Jan 23, 2004 | 12:48 AM
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should i remove the sleeve?
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Old Jan 23, 2004 | 12:48 AM
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should i remove the sleeve?
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Old Jan 23, 2004 | 01:45 AM
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my old gslse engine had low end and alot of high end, i had a gsl before and i did alot of stuff to it and it doesnt compare nothing to the gslse. theres porbably something wrong on you SE but it shouldnt. dont remove the sleeves because it will take your low end off, check if they move. sometimes even afetr you fix them they get stuck. it happened to me before. and another ting too that by gutting out all the cats is make that the ports wont open because it doesnt create enought backpressure, you should it guttet just the 2 little one and left the big one alone. have you change the cap and rotor latelly, that make alot of diference on a gslsebut make sure those ports are openning
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Old Jan 23, 2004 | 08:09 AM
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Lube the ports really good, take em apart if you cant move them by hand. Now that the cat is gutted you may want to do the air pump mod to open you ports. Change cap and rotor, plugs, and wires if they look shity. The car has 35 more horsepower than a 12a and the car only is only 255 pounds heavier. You should be feeling a big difference. Maybe the -SE is just that much smoother and you dont notice. Check your port operation for sure.
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Old Jan 23, 2004 | 08:20 AM
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i am a little confused about the ports. whrer are the ports located? how do i check and see if they are working correctly? this is the first se i have owned so
it is all new to me
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Old Jan 23, 2004 | 08:44 AM
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Above the exhaust and under the intake runners. Do a search for pics and stuff. Lots of port info out there. Good learning.
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Old Jan 23, 2004 | 10:25 AM
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When I purchased my SE it had the same symptoms, although it didn't want to rev past 5k. Since, I have replaced the fuel filter, plugs, wires, removed sleeves, and cleaned intake and injectors...Now she runs awesome!!! The thing is impressive And I noticed NO low end loss and a good high end gain from removing the sleeves. You can also remove those nasty actuators from the manifold......6port actuation is crap!!
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Old Jan 23, 2004 | 11:29 AM
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do i need to take the exhaust manifold of or the intake off to get to the ports? does any body have any problems with removing the ports? i am going to replace the injector seals today . is this a good time to check the ports?
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Old Jan 23, 2004 | 11:41 AM
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If you have the injectors out get them cleaned. It is the best time to check the ports (youll have everything off) Youll be looking right at them.
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Old Jan 23, 2004 | 03:01 PM
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If the ports are not moving at all it is probably best that you take the full intake manifold off and clean it out good, then you can put it all back together with new gaskets. Last year I took my intake manifold off and cleaned it out. This allowed all of the crap that was causing the sleeves not to move to get out of the system.

It is best to run the sleeves off the air pump. Running them off the airpump allows you to decide about were you want them to open. If I can find the links that I used I will post them. Do a search.

The sleeves are not useless. Because of the sudden closing of the intake ports a pressure wave is created. This pressure wave travels up the intake plenum and into the open intake port of the other rotor. When the sleeves are shut they allow this process to work better, which yields more torque. At ~4k rpm the sleeves open to allow more air to enter the motor.
This is how I understood the process to work. If I am wrong please correct me.

If you have the money get a straight pipe put in place of the gutted cats. The gutted cats will cause turbulence in the exhaust system, which causes back pressure. I don't know if this will make to much of a difference, but every bit helps.
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Old Jan 23, 2004 | 03:47 PM
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Originally posted by Nick-7
If the ports are not moving at all it is probably best that you take the full intake manifold off and clean it out good, then you can put it all back together with new gaskets. Last year I took my intake manifold off and cleaned it out. This allowed all of the crap that was causing the sleeves not to move to get out of the system.

It is best to run the sleeves off the air pump. Running them off the airpump allows you to decide about were you want them to open. If I can find the links that I used I will post them. Do a search.

The sleeves are not useless. Because of the sudden closing of the intake ports a pressure wave is created. This pressure wave travels up the intake plenum and into the open intake port of the other rotor. When the sleeves are shut they allow this process to work better, which yields more torque. At ~4k rpm the sleeves open to allow more air to enter the motor.
This is how I understood the process to work. If I am wrong please correct me.

If you have the money get a straight pipe put in place of the gutted cats. The gutted cats will cause turbulence in the exhaust system, which causes back pressure. I don't know if this will make to much of a difference, but every bit helps.
Very well said, need to add that when the ports open to let in more air, it also lets in more gas.
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Old Jan 23, 2004 | 04:01 PM
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Get some RB headers and presilencers since you don't care about emissions. I also recommend the air pump mod because exhaust packpressure is the devil.
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