2002 vs 1999 idle

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mikecronis
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2002 vs 1999 idle

Post by mikecronis » Sun Nov 27, 2016 6:21 pm

By my ear (not the tach, which is steady) I've noticed the idle on the 2002 tends to be a bit lope-y like the LS3 is. I'm pretty certain the cam on the 2002 models have a truck's camshaft (from the LQ4?) to improve midrange response and torque to 345hp, which is nice. Has anyone noticed the idle by your ears tends to dip-out a little here and there? Anyone who's owned a Corvette LS3 will notice this in a more pronounced way. Either that or my fuel injectors or wires/plugs are jacked.

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Scott Chab
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Re: 2002 vs 1999 idle

Post by Scott Chab » Sun Nov 27, 2016 11:45 pm

SLP cars did not have truck cams in them. They were the factory f body cams.

RPMs raising and lowering randomly could be a vacuum leak, spark problem of a fuel problem.
Last edited by Scott Chab on Mon Nov 28, 2016 3:17 pm, edited 1 time in total.
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NBrehm
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Re: 2002 vs 1999 idle

Post by NBrehm » Mon Nov 28, 2016 2:21 pm

The cams were virtually the same as the Vette and 6.0 in 01-02. The 98-00 F-Body actually had a slightly more aggressive cam than the 01-02

01-02 Vette: 198/207 .467/.479 116 <---- This may be a typo on the source, I believe the Vette was also 196 intake, but not sure
01-02 6.0: 196/207 .467/.470 116
01-02 F-Body: 196/207 .467/.479 116

00 and older F-Body: 198/209 .500/.500 119.5

The extra lope on the newer ones came from the 116 LSA as compared to 119.5, but the 01-02 had less duration on both sides because of the 98-00 having EGR. End result is likely a wash power wise.
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mikecronis
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Re: 2002 vs 1999 idle

Post by mikecronis » Mon Nov 28, 2016 3:18 pm

You're saying I may have a PCV issue vacuum-leak? It's possible. I just got the car a month or two ago.

Here's what I read from here and a few other sources: http://www.ncpontiacs.com/differences19982000.html

2001

1. A small percentage of 2001 and 2002 LS1s actually had LS6 blocks which had a different part number and a darker metal cast
2. Starting 2001, all LS1s came with an LS6 intake manifold without an EGR system
3. Advertised HP output was changed from 305 to 310 on base LS1s and from 320 to 325 on WS6s and SSs
4. 2001-02 cars have a smaller cam from the Vortec truck engines to increase low end torque
5. 2001-02 cars had 28 lb fuel injectors like the 98 cars (albeit different part numbers)
6. WS6 cars had a redesigned 5 spoke rim which was more wavy
7. WS6 cars got less suspension upgrades from a base Trans Am suspension than previous years
8. Manual transmission cars all came with the Z06 clutch

2002 - Last year of the F-body

1. 35th Annivesary edition of the Camaro, and Collectors Edition Trans Am available
2. 2002 LS1 head gaskets redesigned. The new ones are a pressed metal, as opposed to the graphite ones and are no longer specific to the side of the car theyre installed on
3. 2002 cars continued with the LS6 intake, 28 lb fuel inectors and smaller truck cam
4. 2002 continued the use of an LS6 block in some LS1 F-bodies
5. A factory supported optional 345 HP option could be ordered from SLP
6. Manual transmission cars continued use of the Z06 clutch
7. Some 2002 model F-bodies came with a revised rear view mirror that had the map light buttons on the bottom, rather than the front.

NEW OR CHANGED FOR 2001 MODEL YEAR

Camshaft from LQ4 6.0-liter V8 (Vortec 6000) Truck Engine
Eliminate Exhaust Gas Recirculation (EGR)
Increased Volume Fuel Injectors
Increased Flow Air Cleaner with Larger Mass Air Flow sensor (MAF)
Pup Catalytic Converters
Cast Exhaust Manifolds with New Gasket
Reduced Tolerance Main Bearings
Revised Oil Level Tube and Indicator
Extended Maximum Oil Change Interval
Two-point Water PumpVapor Vent
Sleeveless Coolant Sensor
Revised Powertrain Control Module Calibrations
Revised Rocker Cover Castings

LQ4 CAMSHAFT
Powertrain engineers found an elegant, cost-effective answer when the platform team asked for a five-horsepower increase in the 2001 LS1: They borrowed a billet-steel camshaft from the LQ4 Vortec 6000 truck engine. The new cam has more advance and different timing, delivering more torque lower in the rev range. Coupled with an improved air cleaner developed for the LS6 V8, the new cam increase horsepower by five in the Firebird
.

So I was wondering if the LQ4 might have a different lope so that the engine idle is a little less smooth than the 1999 Firehawk. My idle is very smooth but by my ear I can hear a tiny bit of occasional hesitation-dip, though not as pronounced as the insanely rough idle of the LS3 (again, by my ear). Some don't even notice the LS3 Corvette rough-idle sound (or the new C7 LT1 for that matter, which sounds like a Maxwell House coffee can full of marbles in my opinion after hearing a half dozen inside the cabin). My 1999 was very very smooth, and idle was best described as, dun-dun-dun-dun-dun-dun-dun. Perfect. This 2002 tends to go, dun-dun-dun-dun-duuuun-dun-dun-dundun-dun-dun. There's no absolute pattern to the "tripping" as I like to call it. I suspect the slight off idle is based on the LQ4.

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Re: 2002 vs 1999 idle

Post by mikecronis » Mon Nov 28, 2016 3:27 pm

After listening to several examples of 2002 SS Camaros and Firehawks on YouTube (it's hard to find stock examples) with the SLP-LM it seems that mine sounds the same, with the idle being a bit rough. I suspect most people don't notice. The 1999 Firehawk had a smoother idle in my opinion.

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BLACK-HAWK
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Re: 2002 vs 1999 idle

Post by BLACK-HAWK » Mon Nov 28, 2016 4:54 pm

You know where you can go to hear stock Firehawk exhaust from 93-02?... The Firehawk Rally :wink: :mrgreen:
someday, i'll have another firehawk...

mikecronis
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Re: 2002 vs 1999 idle

Post by mikecronis » Mon Nov 28, 2016 6:38 pm

Well, the 1999 is smoother in my opinion. Here's a video of my 2002 I just made (closed-caption option available).

https://www.youtube.com/watch?v=DxyH_uyQ_PA

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sleepinghawk
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Re: 2002 vs 1999 idle

Post by sleepinghawk » Mon Nov 28, 2016 10:04 pm

Your hawk has a nice tone to it. Is that the slp1 or slp2? Sounds too quiet to be the loudmouth slp1. I have the lm1 with headers.
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mikecronis
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Re: 2002 vs 1999 idle

Post by mikecronis » Tue Nov 29, 2016 3:20 am

It's a bit quiet in the video, possibly due to the nature of the Nexus 5x recording phone's compression mic. According to the documentation the LM purchased was an LM-1 bought and installed around 2003. I got this replacement for my 1999 (I still miss #423) last month. I don't think the LM-2 existed yet in 2003. I verified with a sound-db tester that it's about 97db at startup outside and 82db (or so) at idle at 6 feet away which jives with other values measured online.

An interesting factor is that I'm in Colorado so the air-pressure is LESS and so the sound is a bit less as well. The density of the air is 18% less at 6000 feet and therefore it is quieter. I remember in my 1999 Firehawk I had at sea-level it was deafening. When I moved it to Denver it was notably more quiet (but so was the Monsoon radio's bass). Less air to "push". Interesting.

Anyway, the idle sounds a bit off to me. If you crank it up or wear headphones you'll hear a tiny bit of hesitation here and there; a little "trip-up" like an LS3 or LT1 but less so. I'm a bit sensitive to sound being a part-time guitarist for 20 years so I can tell when a rhythm is "off". The 1999 "rhythm" was dead-on perfect. This LQ4 sounds a bit punch-drunk (or it could be a vacuum leak). Not sure.

Opinions?

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BLACK-HAWK
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Re: 2002 vs 1999 idle

Post by BLACK-HAWK » Tue Nov 29, 2016 1:42 pm

How many miles are on your hawk?
someday, i'll have another firehawk...

mikecronis
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Re: 2002 vs 1999 idle

Post by mikecronis » Tue Nov 29, 2016 10:04 pm

About 25,000 miles.

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BLACK-HAWK
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Re: 2002 vs 1999 idle

Post by BLACK-HAWK » Wed Nov 30, 2016 2:41 am

I think I found your problem!!, you see most cars general like to be driven more then 1,785 miles a year. You're Firehawk is maaaadddd at youuuuuuu :lol: :mrgreen: ... I just watched the video. I think your ears might be playing tricks on you. Can you really compare your car with the LM1 to a stock Firehawk? No Firehawks came with the LM1 or LM2, they were an aftermarket option. Maybe tricks being played is because there is no sound absorption with the LM1 as there is with the muffler that came with the Firehawks. And again, they like to be driven
someday, i'll have another firehawk...

mikecronis
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Re: 2002 vs 1999 idle

Post by mikecronis » Thu Dec 01, 2016 2:11 am

Agreed. I put 500 miles on it this month. Needs to be driven, yes! I just got it last month! If you listen closely, you can hear a few dips in the idle!

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