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Chevrolet Impala Accessories & Modifications



  • otto42otto42 Posts: 33
    The one I got was part number 88954949.
  • atbearatbear Posts: 322
    Well I posted this a while back, but somehow it's gone.... well, here it is again!

    "What are you planning on modifying?"

    Let's see..
    As of now: Custom Fenderwell Intake w/ 9" cone filter, Borla Stainless Steel Dual Exhaust, 180 degree thermostat, BMR Sway Bars. (I assume I'm at about 210HP now give or take)

    By end of the year: Stage 2 P/P High Velocity Throttle Body, Extended Range High Ratio Rocker Arms, INTENSE Pushrods, Ported Upper Intake Manifold, Upgraded PCM with many features. (I would say I'd be at around 250HP)

    Soon: 3" Downpipe, Highflow Catalytic Converter and ubend replacement, Ported Exhaust Manifolds or Headers (maybe 260 HP)

    Maybe in the future: Centrifugal Supercharger!!!! (approaching 400HP), GM Performance Springs and Struts (NEW!)
  • can any one tell me a good www page to pick up some 19inch rims for my impala?
  • atbearatbear Posts: 322
    Hey, if you're still looking for the 5 spoke Impala LS wheels, check this out!!

    100 bucks!

  • atbearatbear Posts: 322
    I just emailed em, and the ebay auction was bogus. They were $100 per wheel. I told them they better change their description.
  • OK I have a few questions on your MODS atbear:

    1) Borla - I had one on my old car and I really liked it but it was a bit too loud. How loud is their system for the Impala and how much did it cost?

    2) Thermostat - what will this do?

    3) Intake - Your FWI sounds good but I just don't know... I am going to consider it and thanks for the instructions! Now about the Thrasher - Do you think that it is a TOTAL waste of money based on your experience? And what does everyone else think?

    4) How is your MPG with your current mods?

    5) Throttle Body - Where can I get more details on this ?

    6) 3" Downpipe, Highflow Catalytic Converter and ubend replacement - Can you elaborate on these items. What is the "ubend"? What is the "downpipe"? Is the CAT street legal?

    7) Header - Is this a street legal header?

    Sorry for all of the questions. Those are the mods that I may be interested in for the future. I'm going to try and save up enough money for the exaust and intake by this summer so I am just planning way in advance I guess. Thanks!!!
  • atbearatbear Posts: 322
    1) Borla- it is the most quiet exhaust out for our cars. People actually complain that it is not loud enough. It gives a deeper sound, but does not raise loudness much at all. Plus, the quality is TOP NOTCH. You will need to get the drivers side rear hangar welded on at a muffler shop since we don't have dual exhaust originally, but that's no big deal (10 bucks).

    2) The thermostat opens the flow of coolant through the engine at a certain temperature. The stock thermo is 195 degrees. You can get 180 and 160 degree for our cars. The 160 is not good for our engine. The 180 is great! It keeps your engine a little cooler, and cooler mean more power! You won't feel anymore power, but you will feel your peak power for a longer period of time! They are only about $10.00.

    3) On the FWI-- You can do it! Don't feel intimidated. It'll probably take one full afternoon, but it will be worth it!
    If you really really don't want to do it, then I suggest you WAIT for a little while and get the ZZP Cold Air Intake when it comes out. It will be MUCH MUCH better than the Thrasher CAI. I had the Thrasher, and it was not very good at all, and it was not durable. It was falling apart (it's held together with glue!). Also, it did not work as well as I would have hoped. Go to and check out their products. They are about to update their site soon. The ZZP CAI should be out soon as well. I might even upgrade to the ZZP CAI if it works half as good as they are claiming!

    4) My MPG is great! I get about 27-28 MPG going about 78 MPH or so. No drop in MPG with mods.

    5) For Throttle Body etc I suggest you go to these sites:,, Those are our main parts suppliers. For general information and ALL THE KNOW HOW YOU COULD WANT go to You can find out anything there. Go to the message board, and use the Seach feature. It will help you out! Also, you can email ZZP or INTENSE and they will help you too!

    6) Our cars have a 2.5" downpipe from the exhaust manifolds, down to the stock cat, then through a ubend. Now this isn't too bad (except for the ubend), but it could be better. Changing the downpipe from 2.5 to 3" obviously helps flow. The highflow cat also helps flow, and is emissions legal. The ubend replacement can be bought seperately, or as part of the downpipe/cat/ubend combo (they are sold together usually). The ubend is exactly that, a U bend in the piping that really restricts flow. It's good to get rid of that!

    7) Headers don't really have any impact on whether something is legal or not. Headers are NOT needed for us. The only way I'd get headers is if I Supercharged my car. We just don't flow enough air to warrant the price of headers. We will have 3 different choices on headers soon: TOG, S&S and SLP will be making headers for our cars. SLP's should be out in February, and is looking like the best bet for us. Again, Headers are not needed unless you are HEAVILY modded.

    ECT) You really don't need to mod your car at all unless you are gonna mod a good bit. Intake and Exhaust is good if you have future plans, but it won't give you a big gain by itself (nothing noticable). You might see a little gain on the highway, but it's not cost effective. But if you want to do it, and have other plans, you can't go wrong with the ZZP CAI and the Borla Exhaust. The Borla Exhaust is TOP NOTCH, but you will need to get a muffler shop to weld the drivers side rear hangar on, since we don't have dual exhaust originally. PLEASE LET ME KNOW IF YOU HAVE ANY MORE QUESTIONS!! GOOD LUCK!

  • I just copied and pasted everything in your message into a Word document so I have it for future reference. Very good stuff.

    I'll be waiting until this summer anyway or maybe even next summer so when the ZZP CAI comes out I'll be looking into it. I'll stay away from the Thrasher for sure.

    I'm definately going to do some light modding in a year or two as long as the bank account (and wife) lets me.

    Intake, Borla exaust, TB, thermostat, and the downpipe / CAT combo sound like a good way to go for me. If it amounts to like 20 more "usable" HP and more tourqe then I'll be happy like a pig in sh*t.
  • atbearatbear Posts: 322
    Great! With Intake/Exhaust, TB, thermo, and downpipe I see you at around 210-215 HP. Another thing you should look into in the future would be rocker arms. Lots of HP to be gained with them! BTW GM just release a new Stainless Steel Performance Exhaust system that would be great for you! Much easier on the pocket than the $700 Borla system. It's GM Part #12498617 and should be around $400-450. Good luck
  • Yea $400 is much easier then $700 LOL! I'll check it out. Thanks for the tip.

    Noob question: What are rocker arms?

    What do you think this item for the tranny:
    (found it on

    AutoTrans Interceptor Electronic Modulator is a permanent adapter plugged into the existing wiring harness with adjustable microprocessors.
    Increase transmission line pressure reducing burnt clutches & bands
    Eliminates the need to install complicated valve body kits
    Compatible with specific computer controlled transmission applications
    Tighten up those shifts and put a little snap in your driving
    Easy, plug in installation
    The AutoTrans Interceptor cleans up the vehicle's signal, while improving shift quality and increasing vehicle performance. Fine tune your transmission!
  • atbearatbear Posts: 322
    Yeah, that GM Exhaust should be a good system. I've heard really good reviews so far.

    Rocker Arms are the little arms that connect to the camshaft inside the engine right underneath the valvecover. What they do is create the effective duration of the valve lift, letting the air in and out of the cylinders. The higher the ratio, the more air being moved by the cam. ZZP makes some good High Ratio Rocker Arms for our engine. High Ratio Rocker Arms will give you about 15-20 HP by themselves.

    The AutoTransInterceptor has had mostly negative reviews. I would stay away from it if I were you. If you want those features, plus many more, I would suggest a DHP PCM. DHP (Digital Horsepower Performance) is a company that reprograms our cars computers (PCMs) with higher performance features, while still maintaining full driveability and comfort features. Go to to read about it. It's THE BEST reprogrammed PCM for our engines. Good Stuff! The one for the Impala should be out in a few months. I will get one as soon as they are out!
  • Rocker ams look like a very good and safe mod.

    I'll stay away from the autotransint.

    What do you think about having the muffler removed in favor of a higher flowing resonator just for sound?

    The stock exaust should be good enough once the ubend is removed yes?

    I know the full setup is best but I'm trying to get the most HP for my money:

    My Stage 1:
    Thermostat $12
    ZZP CAI $220 ???
    HV stage1 TB $180

    My Stage 2:
    ubend replacment $65
    replace muffler?? $100
    rocker arms $300

    Hmm that comes out to around $900 bucks. I'll have to get everything in part 2 installed at a shop so I'll have to see how much that will cost but all in all that's not too bad.

    What do y'all think?
  • atbearatbear Posts: 322
    You don't really need exhaust mods (except for the ubend), the stock exhaust flows plenty enough for your plans. Only do the exhaust if you want sound! Yes, do the ubend removal, that is a good idea. The downpipe/cat/ubend combo will give you more gains than a cat-back exhaust system. The resonator is not a restriction, it's a straight through design. The stock mufflers flow plenty. If you don't want exhaust for sound, then just leave it like it is.

    You don't need to have any of these things installed in a shop. They are all simple bolt ons that you can do yourself very easily. I put everything I have on myself, and all I have are simple tools.

    I'm not sure what you're looking for so I can't really give you a "Stage 1-Stage 2" model to follow, but if all you are doing is what you posted I'd do it this way:

    Stage 1:
    Ubend replacement

    Stage 2:
    Rocker Arms
    Throttle Body

    What you might want to look into is the ZZP Stage 1 Performance Package (about $500). That will give you most of what you're looking for, for a good price. I'm personally getting the Stage 2 Performance Package, which is much more radical, and gives more performance (but it costs over $1000!).
  • OK. I'm very new to this 3800 engine. But more ponies seem well within my reach. :)

    I think my best path is to wait until the spring and go for the ZZP CAI assuming its available and the Ubend replacement. I thought the ubend replacement had to be welded into place?

    Then my next step when I have the cash is the ZZP stage 1 performance package kit. Not a bad price at all for all that you get but what is the fan switch and do the UDP's really make a difference?

    Thanks again for all your great advice. I've been over at clubgp and its a good site but we need an Impala section over there...
  • atbearatbear Posts: 322
    The 3800 has a lot of potential. Mainly because of 1) It's large displacement, 2) It is strong, well built and durable, 3) It was made for durability and drivability so it has potential for tuning.

    Yes, the ubend will have to be welded to the cat, but if you get the downpipe/cat/ubend all together, it's just a bolt on. Take the old one off, put the new one on.

    The fan switch is to have control of your cooling fans (you don't really need that). The UD Pullies take away some of the parasitic loss that the accessories pull from the motor. Those don't really do much either. Your choice whether you want those things. I'm not getting them.

    Please remember, the Grand Prix GT and the Impala are basically the EXACT same car. It has the same engine and transmission, and they are both W-Bodies. The Impala has a little stronger frame, and of course the PCMs are different. Other than that, pretty much everything that will work on a Grand Prix GT will work on an Impala. So, ClubGP is an excellent source of info for us!
  • OK. I'm very new to this 3800 engine. But more ponies seem well within my reach. :)

    I think my best path is to wait until the spring and go for the ZZP CAI assuming its available and the Ubend replacement. I thought the ubend replacement had to be welded into place?

    Then my next step when I have the cash is the ZZP stage 1 performance package kit. Not a bad price at all for all that you get but what is the fan switch and do the UDP's really make a difference?

    Thanks again for all your great advice. I've been over at clubgp and its a good site but we need an Impala section over there...
  • otto42otto42 Posts: 33
    Hey. I have a 2002 Impala LS. I've been pouring over schematics trying to work out how to disable the DRL with minimal impact on the rest of the system, and without going the full 9 yards and hooking up a surveillance mode switch like in the 9C1/3's.

    If anyone is more daring than me, then here's how you do it:

    Disconnect the negative battery terminal. Pull off the Junction Block Underhood on the right side of the engine compartment. It looks held in by two bolts and is right behind the right headlamp. Crack it open. Look for a light green and black wire (striped, probably) hooked to a spot labeled D3. Cut it or disconnect it in whatever fashion. Make sure to seal it up real good with electrical tape and so on so you don't short anything later by accident. Heck, put a switch on it if you like (one that can handle 12 Volts and possibly up to 15 Amps) and mount it somewhere handy. Close it all back up and put it back together. Reconnect the battery. Start 'er up. Your DRL's should now be disabled (I think).

    I'm going to try this next week when I'm on xmas vacation and take some pictures. But if anyone wants to try it before me, if you've got the guts ;-), then go for it. But you're on your own, I hold no responsibility for you breaking your car, etc. Still, I think it'll work.
  • garywgaryw Posts: 116
    Good thing you did that - those DRL's are so dangerous and they must be real annoying to you from behind the wheel.

    And a big thank you from those of us who are trying to see you in adverse conditions.
  • otto42otto42 Posts: 33
    Hey, I haven't done it yet.

    But believe me, if I want you to see me, then you'll see me. What I don't want is to run my spiffy brighter headlights at low power all the friggin' time.

    And yes, frankly, I find the DRL's to be extremely annoying, on both my and other cars. They don't improve visibility and they don't improve safety (reference any study you care to look up). Why do we have them again?
  • bh0001bh0001 Posts: 340
    I would really annoy you. I drive with my full lighting system on all the time. Low beams with fog lights. All the time, every time I'm in the car.
  • atbearatbear Posts: 322
    DRLs do improve safety. They make cars easier to see. It's the truth. Having said that, there's no law against removing them, so do what you want.
  • Would you be willing to document your mods and plans for a How-To article?
  • garywgaryw Posts: 116
    Screw studies - how about just some good old fashion common sense. Remember when that mattered and worked :--)

    All I know is that DRL's allow me to see cars sooner than later - in any environmental condition. I much prefer to see your "spiffy brighter" headlights than none at all.
  • atbearatbear Posts: 322
    "Would you be willing to document your mods and plans for a How-To article?"

    Sure that'd be no problem! I sent you the instructions and a picture of the Fenderwell Intake. I'm sure you have a ton of email to sift through. I have an updated version I'd like to send you that's a little clearer, so let me know when you want me to send it to you!

    Also-- my BMR Sway Bars came in this afternoon, so I'll be putting them on in the next couple of days. I'll try to create a How-To or at least, I'll have a before and after opinion. I expect a drastic improvement after what I've heard about them!

    My other mods should be done within a month or two, so I'll let you know about those then. I might be getting the downpipe/cat/ubend in the next week or so, so I'll let you know about them too.

    Write me an email when you're not busy, letting me know what you'd like, and when you want me to send you the updated FWI instructions. Thanks!
  • otto42otto42 Posts: 33
    Bah. How am I supposed to run from the cops at night with my headlights on? ;-)
  • Hm, I think I remember your e-mail. I gotta check. I've been receiving a lot of virus attachments so I may have cranked up my firewall too high.
  • "Would you be willing to document your mods and plans for a How-To article?"

    That would be cool.

    It would be great if there was one web site that had Impala how to articles, reviews, and a great message forum. I know there are all of these scattered resources all over the place but it would be nice to have it all in one dedicated site.
  • atbearatbear Posts: 322
    Not sure if you've checked it out yet, but go to night_owl1's (Nathan's) It's awesome! Good work Nathan!
  • I did have a lot of mail quarantined so I gotta go through it all. I posted atbear's fender wall intake project. That was a great article, I only had to format it in HTML and upload it. Karli sent me photos of her Impala. She painted the body molding to match the car.
  • Its not a woman, its a car. Please. LOL.

    But seriously I was looking at my car (its black) and I was thinking that it would look great with chrome along the sides like I see on some other cars. Has anyone done any good looking exterior mods woth chrome?

    I'm gonna get the carbon fiber bow tie on ebay:

    That looks so muvh better then the blue.
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