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2000 Seville STS
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Discussion Starter #1
OK guys and gals. I know this has all been said before in previous threads, but if your like me you never get sick of passing along info to another driver. I have a 1997 Seville STS (black on black) with about 175,000 miles on it. The struts are bad, but thats another story.

My friend just picked up an 1994 Impala SS. I can whoop him right now by a long way, but he is starting to pull the old upgrade card on me. He's getting some major upgrades in the exhaust and intake department; along with a performance chip and 3.73 gears. Im a bit worried that after he does this he may pull on me if I dont do something soon. He has the venerable LT1 motor which loves upgrades. He has 265 horses right now with about 330lbs of torque. After the upgrades he will pe pulling about 335 horses and 375lbs of torque. Im estimating a low to mid 14 in the quarter. (that hurts because Im only running a 14.7-14.9)

I know I cant do a chip because its ODBII. I need some good ideas for any power building ideas, the only catch is I have to stay emissions legal for the state of MO's Gateway Cleanair System. It cant trigger the check engine light or I WILL fail. They have eliminated the roller test next year in liue of a computer check. Now if the upgrades are removable I will just take them off.

Here's a few ideas I would like to hear about:
1.Bigger throttle body (any difference)?
2.Cold air style intake (either handcraft or retail)?
3.Lower thermostat (160 or any other)?
4.Exhaust?
5.Head machining to raise compression?
6.ANY other ideas you may have would be great.

Please help me, I need more power. My goal is 365 horses with 385lbs of torque and a high 13 low 14 in the quarter. Help me keep the Caddy on top.

Thanks again, you guys and gals rock.
 

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Throttle body is NOT an option, CAI is a good idea, lower stat will do nothing, exhaust is a good idea, head machining is BAD idea. In the end you're not going to be able to keep up with the Impala SS due to it's ease of modification compared to your car. You have a car that's just NOT easy or cheap to modify. Sorry.
 

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2000 Seville STS
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Discussion Starter #3
I have a plan, but it will take a while.

Why is headwork a bad idea. I have a 1979 Malibu with a vortec 350 custom built and I took the vortech heads and had them machined to open them up, it made a world of difference. Is it the computer not being able to compensate for the change (thus triggering the SES), or does the North* not take well to head mods. If you remember the STSi had some head and exhaust work done and they pulled another 50 horses from the rig. Just wondering, not trying to argue. I dont have as much experience with this engine as I would like, Im still a classic smallblock man. Thanks again.
 

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Re: I have a plan, but it will take a while.

The Northstar does NOT lend itself to performance mods. The STSi was a custom vehicle that was totally supported by the GM powertrain engineering department. Since I doubt you can muster that kind of technical muscle, and since I'm sure you're interested in being able to drive it on the streets, pass inspection, have some reliability, etc. (all things that Cadillac didn't need to bother themselves with when building the STSi), I'd say stick with the small-block.
 

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2000 Seville STS
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Discussion Starter #5
Re: I have a plan, but it will take a while.

Well, I will agree with that and respect your knowledge on the situation. Thats a very good thought. So lets talk superchargers. I have been to caddyinfo.com looking under the Northstar supercharger page and found some good information on a supercharger. You have any idea of the legitimacy of this website and the supercharger project. If I supercharge the car I will definitely be replacing the Northstar with a very low miles replacement. It says no mods are needed to the OBDII computer and if the kit is like other supercharger kits I can just pull it out every two years for emissions purposes. Im not at all against working on a car. I have built my Malibu from the ground up, and helped on many other severe overhaul projects. (you should see what Im going to do with this old 1984 Celica/Supra I picked up, if you love engine swaps and such you would flip)

Katshot said:
The Northstar does NOT lend itself to performance mods. The STSi was a custom vehicle that was totally supported by the GM powertrain engineering department. Since I doubt you can muster that kind of technical muscle, and since I'm sure you're interested in being able to drive it on the streets, pass inspection, have some reliability, etc. (all things that Cadillac didn't need to bother themselves with when building the STSi), I'd say stick with the small-block.
 

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1984 Fleetwood Brougham coupe
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Re: I have a plan, but it will take a while.

Check this site out. They seem to know more about modding the Northstar than anyone.

http://www.chrfab.com/


523 hp & 357lb-ft @7700RPM out of a Northstar is damn good. Granted it might be a race engine but its still awesome.
 

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Re: I have a plan, but it will take a while.

Superchargers are great but I would just warn anyone planning on installing one on a Northstar, that the head gaskets will most likely not stand up to any significant boost pressure. Can the Northstar be made to handle a blower? Hell yeah. Is it gonna be an expensive proposition? Hell yeah. Will there be any PCM work needed? Hell yeah. The best person I can think of to ask "specific" PCM questions to would be Ed Wright at www.Fastchip.com
 

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Discussion Starter #8 (Edited)
Ooooooooh, now were making progress

Well, that is really what I wanted to hear. I know the head gastket is a weakpoint in all cars. I have no intentions on getting rid of this ride in the next millenia.

I only wanted to put 4.5-5 psi through the engine, I know thats pretty low. I also know a stock LT1 is suppose to handle that without a problem. Does that mean the stock Northstar is inferior. Well, I choose to say no. How long would you expect a stock Northstar with 20,000 miles or so to hold up to a 4.5-5psi boost without major mods.

How much do you think a newly rebuilt caddy tranny would take without getting too fussy. I was just wondering about your opinion.

I will have plenty of money to spend in a year or so but until then I just may have to wait and start the build from scratch. I am going to get the whole thing constructed and ready before I install it into the car. But I am going to get ahold of this fellow at Fastchips.com.
 

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Re: Ooooooooh, now were making progress

4 to 5 psi seems to be not even worth the install...i think a lawn mower could handle that..LOL just kidding...seriously it should be able to handle up to 8 psi with no problems...reliability issues are another issue..Theoretically the engine can last as long as it would without the charger..Depends how often you lay into it...burn outs ect ect..

Did you consider a shot of NOS ?
 

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Re: Ooooooooh, now were making progress

ty at dp has some hookups on custom turbo setups, at domesticperformance.com there doing a setup for aurora's, so im sure they could do it for a STS, the link goes to the turbo manufacture, and they even say they'll do 1 offs. but im sure its at least 6k.

why don't you just get a freeflowing exhaust with highflow cat, and a CAI. that would put you at around 14.4. then get a NX 75 shot setup for when you need it (racing the impala) with that you wouldn't have any driveablility problems because your only using it once in a while. you can also talk to them about highstall convertors, YANK convertors said they made a few highstalls for the 4t80e starting at $850 for a 2800-3000 stall, anything higher would through codes without a pcm reprogram. anyone know what the stock stall is??

ive heard good things about RSM racing's 80mm tb w/ dyno results to prove it, and ive heard that it does NOTHING w/ dyno results to prove it....
 
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