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I am the proud new owner of a 1991 Si 2.1 B21A (no 4ws, though) and I love the car inside and out. It drives like a dream, but I'm running it completely stock. I'm bolting on a cold air intake sometime next week, but after that I don't know what to do. That's where all of you experienced moders come in... I'm looking to boost HP, esp. in the 1000-2500 range. I'd like to spend as little as possible (duh) but am more focused on getting the most out of my car. I'd like to do some cheaper mods now, nut leave it compatible for some more expensive and involved mods later on. If you have any suggestions or have done something yourself, I'd love to hear about it. Thanks,
~Joe
 

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Danny D's second in Command
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hate to say it but u need to search ther has been a ton of threads on here about simple and cheap mods
 

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Don't get upset if people are rude to you man, but someone comes on here every week saying the exact same thing. Spend a little time searching and reading the FAQs and you will find everything you need already documented.
 

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okay... okay.... here is a free mod. are you ready?.... port match the intake manifold.... okay i know you dont get much with this mod but its free if you have a dremal tool. what you do is you take a intake mainifold gasket put it on the intake manifold and scrib a line then grind off the extra and round it out to smooth out the intake are flow. ( only do this on the intake manifold side. the part were it meets up with the engine and please use a new gasket) i have yet to do this on my lude but i did do it on my brothers dsm.



warning: If you some how mess this up I am in no way responsible!
 

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Kickass truck missed
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yup.. i think you got a cut a little here and there.

there is a write up on this somewhere.

also LSD has a CAI made for our cars... no cutting required.
 

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You are looking for gains in the "1,000 to 2,500" range.

You will need some very special cams for that. Our engines don't make much torque under 3,000 rpms. They begin to feel happy around 3,500 rpms and really don't stop feeling happy till about 6,000 rpm.

You bought the wrong car if you want power down in that range.

1,000 to 2,500 rpms is domestic V8 country.
 

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well a extremely cheap mod would be to pull your compressor out.... you will lose your A/C, but if you can stand the heat for some more power.... its worth it... all you got to do is pull the compressor and get a shorter belt.
 

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How much power does a freely spinning A/C pulley actually steal? Because the compressor clutch doesn't engage until you hit the little button on the climate control, so I doubt there's actual gains to be had there. Unless someone's got dyno sheets to prove me wrong, I'm inclined to believe that the camshafts steal more engine power than the disengaged A/C compressor pulley...
 

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adjustable cam gears set at +4/-4 in/ex is known to boost low rpm torque by quite a bit. not exactly sure what rpm range, but it is impressive, and cheap too
 

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motoxxxman said:
adjustable cam gears set at +4/-4 in/ex is known to boost low rpm torque by quite a bit. not exactly sure what rpm range, but it is impressive, and cheap too
if u read i think its chris's website prelude3g.com ull see that someone posted results on simple engine mods and they claimed that adj. cam gears was teh best mod with very good low end power and tourque increases when they found themselves spinning the tires with out noticing it rollin away from stop signs and wat not
 

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alanoneil said:
How much power does a freely spinning A/C pulley actually steal? Because the compressor clutch doesn't engage until you hit the little button on the climate control, so I doubt there's actual gains to be had there. Unless someone's got dyno sheets to prove me wrong, I'm inclined to believe that the camshafts steal more engine power than the disengaged A/C compressor pulley...
yes but, you also loose weight, and think about it a smaller belt takes less energy to move, and if you actually feel it move around. Its not so free spinning, its got some restriction. i noticed a difference when i pulled mine out...
 

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removing the a/c compressor removes a good amount of weight, removes a restriction (from friction), and also removes rotational mass.

the a/c compressor doesnt rob power just cuz of its friction, it is a rotating weight (pulley) that causes the crank to accelerate and decelerate slower; rotational weight.

all 3 combined free up power/acceleration. the amount of friction from the a/c compressor is extremely low when the a/c is off, the main source of freed power is from removing the rotational weight of the pulley, and the extra length of belt. second source is removing like 40 pounds from the vehicle. 3rd and least effective source of freed up power from removing the a/c is the actual friction of the system
 

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motoxxxman said:
removing the a/c compressor removes a good amount of weight, removes a restriction (from friction), and also removes rotational mass.

the a/c compressor doesnt rob power just cuz of its friction, it is a rotating weight (pulley) that causes the crank to accelerate and decelerate slower; rotational weight.

all 3 combined free up power/acceleration. the amount of friction from the a/c compressor is extremely low when the a/c is off, the main source of freed power is from removing the rotational weight of the pulley, and the extra length of belt. second source is removing like 40 pounds from the vehicle. 3rd and least effective source of freed up power from removing the a/c is the actual friction of the system
so you agree with me that removing the A/C system is worth it if i\you dont need A/C
 
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