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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Discussion Starter #1
Does anyone know since the inception of the northstar, which intake flows the the best?

I've seen metal intakes, the plastic intake on my 98 eldorado, and the 2000+ version. Which one is the best? Thanks
 

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1997 ETC (GAVE TO STEPSON 2011), 2000 DTS (RIP)
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1,702 Posts
Re: northstar intake manifolds

2000+ supposedly, according to Cadillac
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Discussion Starter #3
Re: northstar intake manifolds

the 2000+ intakes have the "skinny" injectors. Therefore to swap to the 2000+ intake, I'll need the intake, fuel rail, injectors and injector harness. Hopefulley it should have the same plug connector as the 98 version.

was the intake redesigned for the 2000 models? what changes did they make?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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67,978 Posts
Re: northstar intake manifolds

2000+ intakes are quite different from 1999-.

The 2000+ intake uses a slightly different lower air log with the 8 tuned runners looping up and over to the opposite side/port. The overpressure valve was moved from the recess behind the P/S pump to just under the plenum spigot, where it changed from a flapper to a poppet mushroom. The PCV lines are routed entirely differently, and the PCV "valve" itself changed to a fixed orifice some time after 2000 (?), so the airflow calibrations are different.

Your 1998 throttlebody bolts to your original manifold with a rubber gasket - the 2000+ uses a flex rubber "plenum", so you'll also need to change the entire throttlebody, sensors, EVAP purge system, MAF, MAP, IAC, all the intake air ducting, and maybe the water crossover.

You would probably need new cylinder heads as the manifold mounting is different. (Actually, the entire engine is a complete redesign for 2000+)

Several 2000+ intake manifold pictures in my albums. Click my username, open the profile; Left column, 2 albums 6 pages of STS and Northstar stuff.
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Discussion Starter #5
Re: northstar intake manifolds

oh my goodness......I wonder what prompted all those changes....
 

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'98 STS (RIP @ 206,xxx miles)
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Re: northstar intake manifolds

oh my goodness......I wonder what prompted all those changes....
Below is a post that I saved from 7 years ago. Folks who have been here for a while will recognize the writing style of the author.


"Fundamentally the engine was substantially redesigned for 2000. The
2000 engine got completely new cylinder heads that have redesigned
combustion chambers, less compression and roller cam followers.

As far as the fuel requirements go the switch to regular fuel was
managed thru the reduced compression ratio and the improved
combustion chamber. The compression only went down 1/2 a
ratio...normally if nothing changes in an engine it would take a
full 1 to 1.5 ratio change to accomodate regular fuel from premium. In
other words the compression went from the 10.5:1 of the earrly
engines to 10:1 in 2000. Normally , if the compression ratio was
10.5:1 and you wanted to change the fuel requirement to regular from
premium you would change the piston/head/deckheight to get the
compression down to 9.5:1 or 9.0:1. That is where the combustion
chamber redesign comes in. The improved chamber which is more knock
resistant accepts regular fuel with optimum spark timing for max
power with the 10.0:1 compression ratio.

So....the answer to the regular fuel question is the combustion chamber
redesign and the slight compression ratio reduction.

In addition , the piston and rod design was changed to move the
rings closer to the top of the piston to reduce the crevice volume
for HC reduction.

The intake manifold was redesigned with a center feed plenum design
to improve the induction node at full throttle.

The roller cam followers to reduce friction which improves fuel
economy were mentioned.

The cylinder head redesign also included an AIR passage drilled deep
into the exhaust port to improve the catalyst lightoff....the engine
is started cold and extra fuel is added, the spark is momentarily
retarded and a LOT of air is pumped thru that deep drilled passage.
The result is extra unburned fuel in the exhaust, heat from the
retarded spark and oxygen in the air pumped thru the passage....the
result is an exothermic reaction in the exhaust port that travels
down the pipe to the converter and lights it instantly.

One of the more important highlights of the 2000 and later engines
is the ability for a relatively heavy luxury car with a high
performance V8 engine to pass LEV emissions....back in 2000 well
before it was required.

So, the 2000 engine was cleaner, quieter and more fuel efficient. It
makes the same power as before and only requires regular fuel.

In addition, now that the cam followers are rollers instead of
rubbing element followers the oil anti wear package is not depleted
nearly as fast, which allows the oil change maximum interval to be
extended to a maximum of 12,5000 miles under optimum conditions as
determined by the oil life monitor.

One other thing is that the spark plug wires were eliminated with the
coil-at-plug ignition system for 2000."
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Discussion Starter #7
Re: northstar intake manifolds

thank you. That was very informative.... I never knew gm redesigned all that stuff for 2000. Thanks again
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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I pulled this thread out of my archive for the benefit of the new 2000 - 2005 FWD Northstar members. Bookmark the URL for your own files.

The engine redesign info in Post #6 was written by one of the GM Northstar Powertrain Design engineers, the same person who posted the Cadillac Technical Archive way up ^^^ in the top black bar. The Archive also contains an explanation of the OLM by the engineer who did the main work on the algorithms and testing.

Still informative.
 
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