Stock throttle body size
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
Stock throttle body size
Had a bit of confusion when selling the throttle body off my '01 Z06 parts car. The buyer wondered if it was 78mm, and I figured he was trying to determine if it was 78mm vs. 90mm LS2. So I said yes. But he measured it and says it is 75mm. I've seen both #s in the past, but I've never known for certain what the actual stock measurement on an LS1/6 TB is.
So, can anybody tell me for sure? Since ALL C5 TBs from 2000-2004 are the same part #, then mine *ought* to be the same size as all of those years. Is there a difference in TB size from early C5s to later C5s? What size _should_ my TB be?
Thanks,
Fred
So, can anybody tell me for sure? Since ALL C5 TBs from 2000-2004 are the same part #, then mine *ought* to be the same size as all of those years. Is there a difference in TB size from early C5s to later C5s? What size _should_ my TB be?
Thanks,
Fred
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
Thanks for the response! Do you have any way to verify this info? Or is there a sure-fire way to check part #s on the TB itself? I just find it strange that my '01Z would have a 75mm TB on it. Granted, the car was a salvage car w/ a checkered past, but still seems odd to me that someone would have put an older TB on the car. Plausible, but strange...
"AlohaC5" Senior Member
Joined: Jun 2003
Posts: 3,562
Likes: 44
From: Madison, AL
If the C5 Z06 was a salvage car w/ a checkered past you may want to check the VIN on your engine to verify its an LS6 vs. an early model LS1, which might explain the 75mm
Last edited by Gray Ghost GS; Jul 12, 2009 at 05:48 PM.
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
Hmmm...yeah, I still have the block (was hydro-locked when i got the car), so I might check that out. However, the heads were the correct 243 casting, so if it _is_ a 75mm TB, I'm guessing someone had something else on top-- different manifold and TB perhaps-- before and then swapped before calling the insurance company...
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
Received the TB back today, and compared it to the one on my '99 LS1 that's for sale. The outer diameter is a perfect match. However, they have different #s stamped on them. The '99 has 25179793 stamped on it. The "mystery" TB shows 25317951. I can find virtually no information on either, as they are not proper GM part #s. How certain are you (or is anybody) that the TB size changed from 75mm to 78mm in 2000?
"AlohaC5" Senior Member
Joined: Jun 2003
Posts: 3,562
Likes: 44
From: Madison, AL
Contact Gene Culley (Forum Vendor for GM Parts) - he can verify the 97-99 and 00-04 TB sizes 75mm vs. 78mm. I could be wrong....
Last edited by Gray Ghost GS; Jul 15, 2009 at 11:34 PM.
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Instructor
Joined: Feb 2005
Posts: 242
Likes: 2
From: Mims Florida
Throttle body 17113669
I just bought a new throttle body # 17113669 which was suppose to be the 2000 to 2004 piece for Z06 as well as LS1 and the blade and the hole where the blade sits both measure 2.950" . Which times 25.4 mm per inch is 74.93 mm, or about 75mm. I thought that they were suppose to be 78mm? Anybody else have any input?
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
I just bought a new throttle body # 17113669 which was suppose to be the 2000 to 2004 piece for Z06 as well as LS1 and the blade and the hole where the blade sits both measure 2.950" . Which times 25.4 mm per inch is 74.93 mm, or about 75mm. I thought that they were suppose to be 78mm? Anybody else have any input?
In any case, a 3mm change probably wouldn't affect much anyway, but my guess is, any references to 78mm TBs are referring to an aftermarket piece, perhaps, or measurement from a different spot on the TB. Can you provide us the #'s that you see etched in the metal?
Thx,
Fred
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 860
Likes: 0
From: Birmingham AL
Thx,
FT
Le Mans Master
Joined: Jul 2010
Posts: 5,954
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Becayse we always seem to make jokes.
Sorry i cant hjelp with ?
Last edited by helga203; Mar 14, 2021 at 09:28 AM.
Melting Slicks
Joined: Feb 2001
Posts: 2,791
Likes: 355
From: Northville, MI
The LS1 TB will flow a tad over 750 CFM and the engine at readline will flow about 630 cfm. The Z06 flows over 650 cfm as I recall. We had the chief engineer from the engine plant as a guest speaker back in 2000 and he gave a talk to our club about the new, at that time, Z06 engine details. The above is from my 20+ yr memory and I believe I put it in an early 2001 thread.
