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2K views 17 replies 6 participants last post by  MisterBlue 
#1 · (Edited)
Intake opening 86mm
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Connector Gasket 72mm AKA plenum
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Crossover Housing 74mm
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T-body 75mm
 
#7 ·
The 2000+ Northstar had pretty serious revisions in 2000. The ports are different, different sized valves, different compression ratio, different intake manifold design, etc. Granted, all of these changes, individually, wouldn't be considered "major", but together they gave a pretty significant change to the engine.
 
#8 · (Edited)
The 2000+ Northstar had pretty serious revisions in 2000. The ports are different, different sized valves, different compression ratio, different intake manifold design, etc. Granted, all of these changes, individually, wouldn't be considered "major", but together they gave a pretty significant change to the engine.
all of those basically aim to increase the efficiency or power of the motor, yet it still breathes through the same 75mm hole...

if anything, an 80mm TB would be a bigger benefit to 2000+ years...

the holdback, is the fact the spacer plate is part of the water crossover. this makes it a PITA to bore...and it needs to be port matched for optimum benefit

and yes i am aware of the compression drop and use of regular and such...

a 2000+ should still see at least similar gains...
 
#9 · (Edited)
I don't think .2 of a compression drop is anything!
My 99 program in my Fiero has an octane calculator. Yes it will display the octane level that it thinks it has in it and it changes.

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The major performance change in my opinion was the cam profiles.

1999 Cadillac Seville (LD8 (VIN Y))
• Valve Timing (With Ramp at 0.100 mm Lift), Intake Opens 8 degrees BTDC
• Intake Closes 55 degrees ABDC
• Exhaust Opens 51 degrees BBDC
• Exhaust Closes 13 degrees ATDC
• Valve Lift, Intake 8.6 mm 0.339 in
• Exhaust 8.6 mm 0.339 in
• Duration (@ 0.100 mm Lift), Intake 243 degrees
• Exhaust 244 degrees
• Valve Overlap (@ 0.100 mm Lift) 22 degrees


2000 Cadillac Seville(LD8 (VIN Y)) 1.7 rockers?
• Timing, @ 0.150 mm [0.006 in] Lift, Intake Opens 5.6 degrees BTDC
• Intake Centerline 113 degrees ABDC
• Intake Closes 236.8 degrees ABDC
• Exhaust Opens 222.5 degrees BTDC
• Exhaust Centerline 107 degrees BTDC
• Exhaust Closes 13.8 degrees ABDC
• Camshaft Lift, Intake 6.15 mm 0.2421 in
• Exhaust 5.94 mm 0.2339 in
• Valve Intake 10.500 mm 0.4134 in
• Exhaust 10.000 mm 0.3937 in
• Duration, @ 0.150 mm [0.006 in] Lift, Intake 242 degrees
• Exhaust 236 degrees
• Valve Overlap, @ 0.150 mm [0.006 in] Lift 1.98 degrees


1999 Cadillac Seville (L37 (VIN 9))
• Valve Timing (With Ramp at 0.100 mm Lift), Intake Opens 13 degrees BTDC
• Intake Closes 73 degrees ABDC
• Exhaust Opens 51 degrees BBDC
• Exhaust Closes 13 degrees ATDC
• Valve Lift, Intake 9.4 mm 0.370 in
• Exhaust 8.6 mm 0.339 in
• Duration (@ 0.100 mm Lift), Intake 266 degrees
• Exhaust 244 degrees
• Valve Overlap (@ 0.100 mm Lift) 26 degrees

2000 Cadillac Seville(L37 (VIN 9))
• Timing, @ 0.150 mm [0.006 in] Lift, Intake Opens 0 degrees
• Intake Centerline 122 degrees ATDC
• Intake Closes 251 degrees ATDC
• Exhaust Opens 225.5 degrees BTDC
• Exhaust Centerline 106 degrees BTDC
• Exhaust Closes 20.5 degrees ATDC
• Camshaft Lift, Intake 6.15 mm 0.2421 in
• Exhaust 5.94 mm 0.2339 in
• Valve Lift, Intake 10.500 mm 0.4134 in
• Exhaust 10.000 mm 0.3937 in
• Duration, @ 0.150 mm [0.006 in] Lift, Intake 251 degrees
• Exhaust 246 degrees
• Overlap, @ 0.150 mm [0.006 in] Lift 2.04 degrees
 
#16 ·
When I started my Northstar project I had some input like "it can't be done" or "it can't be done that way"
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I am not saying that. I am stating this is the obstacle. From the beginning I have listed this part as the smallest inlet and it has the largest outlet some 96mm I think it was.
This part fails often.
Please don't write in saying you have never heard of that. We stock the part on the self :rant2: and you want to make it weaker.:thehand:
May be you can reconstruct it.

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#1... You could machine a grove in the Crossover or the new flange to hold a T-body gasket/seal. Just like the one in the T-body and just use a second seal.
#2... You could construct a flange for the over sized crossover bore. The flange would need to have three threaded hole and the tube size could be up to 96mm OD.
#3... You would need a short piece of rubber or silicone 96mm id hose and two hose clamps.
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Now you have your T-Body bolted up.
It may work like this Theory. You take your medium size Shop Vac and stick a 4" drier vent hose on it instead of the 2" hose. Now it will not pick any thing up, but it will move air.
Hemi's from the 60's did not have that much good usable power. They did not rule the streets. In 1970 the fastest production car was a Buick.
A major problem with the Hemi was the intake ports, manifold and dual carbs.
To fix this and completely change the way the engine works you need the push the air into the old Hemi.
Now you bolted a blower to this Hemi and it screams. You bolt the same blower onto a 427 Chevy or Ford and it does not have the same power gain or the same power. One design is a pull air in engine and the other is leans more to push air in.
This goes to Volumetric Efficiency. I think if you wet CC'd the intake manifold on a 00+ you would see my concern. It would be hard to argue a larger T-body and the major lower RPM power loss you would get
 
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