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HT4100 4.1, 4.5, 4.9 Discussion, 4.9ltr Northstar performance? in Cadillac Engine Discussion; 4.9, still a good vehicle/engine. Wish I had one....
  1. #16
    z06bigbird is offline Cadillac Owners Connoisseur
    Automobile(s): Sedan de Ville, CTS
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    Mar 2007
    San Antonio, Tx

    Re: 4.9ltr Northstar performance?

    4.9, still a good vehicle/engine.

    Wish I had one.

  2. #17
    Raze's Avatar
    Raze is offline Cadillac Owners Enthusiast
    Automobile(s): 90 Eldo -SOLD-, 98 ETC -SOLD-, 86 XR4Ti Track Car, 07 Ranger
    Join Date
    May 2004
    Atlanta, GA

    Re: 4.9ltr Northstar performance?

    Ok, everything everyone is telling you about not being able to mod this engine is not true. I agree that you should pay attention to base mechanicals first, suspension, brakes, tranny rebuild, engine rebuild, etc before you go to town on making power or you'll just break a lot of parts. That being said here's some info on REAL performance upgrades, not just CAI, bolt on Cat back exhausts, and performance chips:

    I would point you Pennock's Fiero Forum where a 4.9L swap is common in Fieros and the writeups farily detailed. There are 2 I would look at and potentially contact the members for more specific information in your quest for parts:

    1) A 4.9 Turbo setup, it used the stock 4T60 Caddy tranny with a reburned/tuned factory PCM and wiring harnesshttp://www.fiero.nl/forum/Archives/A...-2-064940.html, he's not the origional owner and I couldn't find the origional thread by PBJ (who as I recall is a member here as well) but if you contacted him you should get some info on "Pete" who burns the PROMs for the 4.9L turbo...

    2) Naturally asparated 4.9L performance thread: http://www.fiero.nl/forum/Forum2/HTML/061613.html, includes ported, polished, big valve heads, delta cams/springs using N* pistons in the 4.9L. If you got "Pete" to help you out in the ECU department you'd be able to do this, I think the end result was power output on this 4.9L that was slightly ahead of a N* and the power was made in the lower RPMs when compared to a N*, I want to say "Pete" is in Canada somewhere.

    All of this is great but if you read the threads and do some digging you'll see how much custom work a forced induction build is as there just aren't any off the shelf 'kits' that bolt on. To install a turbo you're going to need to spend a considerable amount of time custom fitting/welding up custom headers to get all that exhaust feeding a single turbo or even 2 turbos. For a roots/screw supercharger you'll need to fab up a custom intake, for a centrifugal supercharger, that'd be the easiest route in terms of customization cause all you'd need is enough space to locate the CSC, fab up a custom bracket, get a longer serpentine belt and plumb up an front mount intercooler into the stock intake, never touching the exhaust unless you wanted to open em up to help flow. Really the only thing you'd have to worry about on a CSC is the harmonic balancer and front crank seal longevity since you'd be 'overloading' it, but regular replacement of the balancer should minimize problems...

  3. #18
    CadillacSTS42005's Avatar
    CadillacSTS42005 is offline Banned
    Automobile(s): 2005 STS4 1SG: GM Acc Lights, Corsa, Platnium Grille, Volant
    Join Date
    Oct 2005

    Re: 4.9ltr Northstar performance?

    Quote Originally Posted by illumina View Post
    There was no 4.9 liter Northstar, and there never will be. If there is badging that says otherwise on a 1992 Seville, someone placed it there to make people think it was the Northstar; the Northstar didn't come out until the 1993 model year on the Allante and Seville STS.
    And the Eldorado ETC

  4. #19
    tagrp is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Feb 2008

    Re: 4.9ltr Northstar performance?

    The reason you can push this engine harder in a Fiero is the the same reason a motorcycle transmission wont work in your car "MASS" the Fiero weighs in at nearly half the weight of theses big Caddies the loads the 4.9l would see in a fiero are no where near what you see just driving to the grocery store and back.

    None of us would expect a transmission designed for a 300lb motorcycle to propel a 3000lb car reliably. V8 FWD and 4000lb are a precarious combination and any performance gains should be approached with that in mind.

  5. #20
    tinderinc is offline Cadillac Owners Member
    Automobile(s): 1992 Cadillac STS Seville
    Join Date
    Nov 2010

    Re: 4.9ltr Northstar performance?

    Quote Originally Posted by illumina View Post
    There was no 4.9 liter Northstar, and there never will be. If there is badging that says otherwise on a 1992 Seville, someone placed it there to make people think it was the Northstar; the Northstar didn't come out until the 1993 model year on the Allante and Seville STS.
    I own a 1992 sts 4.9L Northstar and Ive owned a 1994 sts 4.6L Northstar. It its a northstar motor its factory made and called the northstar 4.9L even tho it is much better than the 4.6L as I owned a 4.6L in 07 and now in 2010 I own the 92 4.9L as its a way BETTER NOTHSTAR...

    I can take a picture of the engine if you want to see....

  6. #21
    cadillac_al is offline Cadillac Owners Connoisseur
    Automobile(s): Cadillac 78 Seville, 78 Coupe de Ville, 92 Sedan de Ville
    Join Date
    Feb 2007

    Re: 4.9ltr Northstar performance?

    that's an interesting tid bit. I'd like to see a picture to see how they labeled or badged that engine. I've been looking for a 92 Eldo just for this reason. I love my 4.9 deville althought the body style is getting dated, The 92 Eldo still looks kind of modern.

  7. #22
    raymondlee is offline Cadillac Owners Member
    Automobile(s): none
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    Jan 2011
    Albany, GA

    Re: 4.9ltr Northstar performance?

    anybody ever shave the heads

  8. #23
    TK8411 is offline Cadillac Owners Member
    Automobile(s): 94 Deville
    Join Date
    Mar 2011
    WPB, FL

    Re: 4.9ltr Northstar performance?

    I made a custom cold air intake for my 94 deville 4.9. It's a 3 inch pvc 22degree elbow and a 2 inch loncg piece of 3 inch glued to a velocity stack behind the headlight. I basically replaced that flex piece and upsized it. I think the stock inlet was 2 inches or less! I insulated it with r-3 duct wrap and sealed it with foil tape. Then I moved the IAT sensor from the intake manifold to the intake tube just after the filter. I have insulated from the elbow to the airbox and insulated the underside and sides of the air box. I have a k&n filter and a 70 series flowmaster. I saw immediate improvements with the cold air and relocated sensor. She runs great and mileage improved slightly. I may move the IAT sensor again up closer to the headlight to see if it gets even better.

    Hey guys, let me know if you have any custom ideas for this 4.9. We need to get a market started for this engine and the transmission too. If we work together we might get some options.

  9. #24
    drewsdeville is offline Cadillac Owners Master
    Automobile(s): 2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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    Oct 2004
    Oak Creek, WI

    Re: 4.9ltr Northstar performance?

    Getting the market started on a fwd lo-po drivetrain that hasn't been produced for over 15 years isn't very likely...

    That said, DIY stuff is never out of the question. One bit of advice though...this engine is severely choked by it's poor flowing, small valve heads. Don't expect many gains by bolting intakes and exhausts on the stock heads (the intake and exhaust can't flow any more than can pass through the heads). If you are going to do it, do it right the first time - Pull the heads and work them over, establishing a capable base, then continue from there.

  10. #25
    Sevillian273's Avatar
    Sevillian273 is offline Cadillac Owners Connoisseur
    Automobile(s): 69 Thunderbird | 90 Seville | 89 Marquis | 72 Torino
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    Oct 2008
    Palm Bay, FL

    Re: 4.9ltr Northstar performance?

    ^ But that's no fun and it doesnt come with shiny stickers and chrome nick-nacks to put under the hood.


  11. #26
    RippyPartsDept's Avatar
    RippyPartsDept is offline Cadillac Owners 10000+ Posts
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    Sep 2007
    Wilmington, NC

    Re: 4.9ltr Northstar performance?

    Quote Originally Posted by tinderinc View Post
    I can take a picture of the engine if you want to see....
    what ever happened to the picture??

    i'm thinking that 'maybe' it's true since "NorthStar" is a total powertrain/suspension/etc system, not an engine...

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