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How to Add Horsepower to the 2004 GXP

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Old 04-16-2006, 03:17 PM
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Default Mass air flow sensor screen

Removing the Mass air Flow Sensor screen in th air intake hose that goes from the air filter box to the throttle body is something that will let more airflow in to the motor but some speed shops dont recommend it since they say it straightens the air flowing to the motor and works as a filter also even though I cant imagine how any debris would get past the air filter and this might void the warranty.I looked at mine but I didnt remove it because Im afraid it would ruin it since its glued or held in by something and I would mybe want to reuse it if the car would not run right.I have removed these from a Buick Grand National I used to own and my 1999 Trans Am and my 98 Grand Prix but all of these have bored out throttle bodys.I do notice that the Grand Prix idle goes up and down but that might be the bored out throttle body or something else but runs fine on acceleration.Another mod we did on the Gran Nationals and Grand Prixs was to remove the weatherstrip at the rear under the hood to leave the hot air out.It just snaps into place and can be removed or reinsalled anytime but when it rains it can go into engine bay and also to remove the engine cover to allow heat to escape.Another mod you can do is unplug the coupler that plugs into the IAT sensor in the intake tract and put the 2 wires from a resistor in each prong of the coupler plug.These resistors you can get on Ebay for $10 and if you know the right part no. they have them at radio shack for around a dollar.What this resistor does is to bypass the Idle Air Temparature sensor that tells the computor the air temperature coming into the motor and gives the reading of 30 degress all the time so the computor will give your car full advance at open throttle instead of retarding your timing if its 90 degress.Your computor will still retard timing if the knock sensor picks up any knocking from the motor so you dont have to worry about motor problems from too much timing advance or bad or lower octane gas.All these are minor mods and will give probably only about 10 HP at the most.
Old 04-16-2006, 03:40 PM
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I hear ya cballweg and have considered doing that but with the nitrous now in, I want the increased air flow registered and need timing to retard, not advance. It would be very interesting to see some dyno results before and after if someone was to do this. Is that just a maf screen? I have been told its the sensor and was printed out a sheet that calls it the sensor.
Old 04-16-2006, 05:38 PM
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Its just the screen.Its located in the mass air flow sensor and in the air intake hose between the air filter box and the throttle body and has a coupler plug going into the mass airflow sensor.You can take it apart with 2 screw clamps that hold the hoses on both sides of the mass air flow sensor and unplug the coupler and remove it from car to knock out the screen but you might damage the screen.Also I dont believe you can buy a new screen alone without buying a new mass air flow sensor since it is glued in which is $100 to $300 im guessing..I know for a fact in the Trans Ams you an only get the screen if you buy a new sensor. and they are $241 from GM..Hope this helps.Let me know if you remove the screen and if it helps the car run better.
Old 04-16-2006, 05:43 PM
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The MAF screen doesnt have anything to do with the timing,just more air flow if I understand your e-mail but the resistor in the IAT does affect timing.
Old 04-16-2006, 06:51 PM
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You are right in that they do have ported mass air flow ends and a whole new bigger mass air flow sensor for some of the high performance cars from the aftermarket to flow mor air but I dont know if you coud convert them over to a GXP.I know that the SLP 85 mm mass air flow sensor for the Trans Ams is off of I believe a GM truck motor and works with the Trans Am computor but they are probably both very simular motors.
Old 04-16-2006, 07:31 PM
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OK for the first time I get it all LOL so many conflicting opinions over this I'm leaving it all alone... I have nitrous jet just after the screen and it'* working very well and dont want to take a step back. I love the 75 shot power level and not having to alter a bunch of other things suits me fine Going to open the air box up though and see about what can be done to get that tube between the two opened up without breaking the "sealed" cold air intake thats already present
Old 04-16-2006, 07:40 PM
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Another thing I failed to mention in that the aftermarket mass air flow sensors dont have the screens in them.I know my Granetelli mass air flow sensor that I installed in my Trans Am doesnt have a screen either.
Old 04-16-2006, 07:57 PM
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The dam thing is so sensetive in the N* all ya have to do is touch the screen with a finger and engine acts up, But I can see how it can choke flow considering the diameter is the same on both sides and that alot of holes to pass air thru, as for turbulance I prefer to have it to make sure the Gas/ nitrous is well atomized as it heads thru the TB. I done alot of looking and havent found a screenless aftermarket
But that not a surprise .... Whats is available for our N*....NADA DANG THING! LOL
Old 04-16-2006, 08:35 PM
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I would say that when yu are touching the scren and it acts up is because you are restricting some of the airflow going into throttle body.The next time try putting your hand in front of it and see if engine sputters or dies.I know years ago you could do that on a carburated car and it would die just like the choke flap on a carburator if it it is set wrong will choke off car too much and make it run rough until it warms up.
Old 04-16-2006, 09:01 PM
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Already did LOL I' had it off a couple times , messing with and figuring out best placement for nitrous/gas jet, It only takes the slightest touch to make a sputter and kills engine dead with a hand over. which obviously would be the case with no air to feed engine. What suprosed me was how sensitive this one is and how fast it stalls. Also could signal there a restriction there to overcome? Do ya think the screen can be removed safely... Ya got me thinking and I'm gonna have a better look at it all in the daylight. Also have you had the top off the dual airbox and what does the tube connect to in inner box. I see the snout has been engineered to "spray" the air directly at the filter but wonder why the tube is so much smaller than the cold air intake tube I discovered when we pulled out headlight assemblies to paint car . These two items could add up to some Hp gainable flow. I get all the flow I need spraying nitrous and gas but the better performance would help cause I'll go broke spraying all the time and alot of others looking for simpler, cheaper ways to mod

I've been thinking of removing snout and tube and glueing a length of 3" inch pipe after dremeling out that hole for 3' to fit into and dremeling the end of 3" pipe'* top off to replicate what ya see???


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