major differences between 52mm and 58mm TB?
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,961
Likes: 2
From: Fort Knox
major differences between 52mm and 58mm TB?
Looking at getting the Holley throtle body replacement for my 86, what is the primary difference between the 52 and 58mm models besides the obvious?
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,961
Likes: 2
From: Fort Knox
other than headers, and a turbo 350 transmission conversion and 120 shot of nitrous - no head work.
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,961
Likes: 2
From: Fort Knox
I run a throtle plate for my nitrous, I wonder if one of these Holley 58mm's will allow me to use the plate...I couldn't imagne why not.
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Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
Intermediate
Joined: Jul 2008
Posts: 39
Likes: 0
I love the throttle body threads.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
Melting Slicks
Joined: Oct 2005
Posts: 3,178
Likes: 5
From: Daleville Indiana
St. Jude Donor '08
I love the throttle body threads.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I found a site where a dyno test was done that showed a power increase of less than 10 when a larger TB was installed, but only within a 1000 rpm band, IIRC 5000/6000. As I recall, it was on an engine with only bolt on mods.
One of the mags did the engine build and test and I'll try to find and post the link.
On a personal note, I've run all three, 48, 52 and 58 mm. Going from 48 to 58 showed me an acceleration increase so dramatic that I swapped it with a Forum member for his 52.
One thing members don't seem to consider is that even though max power may not increase, the fun factor does. When moving to a larger TB, for every incremental increase in throttle opening, more air is allowed to enter the engine (when compared to a smaller TB) which causes the car to accelerate faster. Up goes the fun factor.
In the case of me running the 58, the change from a 48 was so dramatic I decided to move DOWN to a 52 to better be able to modulate the throttle and NOT blast around like Speed Racer.
Jake
One of the mags did the engine build and test and I'll try to find and post the link.
On a personal note, I've run all three, 48, 52 and 58 mm. Going from 48 to 58 showed me an acceleration increase so dramatic that I swapped it with a Forum member for his 52.
One thing members don't seem to consider is that even though max power may not increase, the fun factor does. When moving to a larger TB, for every incremental increase in throttle opening, more air is allowed to enter the engine (when compared to a smaller TB) which causes the car to accelerate faster. Up goes the fun factor.
In the case of me running the 58, the change from a 48 was so dramatic I decided to move DOWN to a 52 to better be able to modulate the throttle and NOT blast around like Speed Racer.
Jake
Last edited by JAKE; Feb 23, 2010 at 04:51 PM. Reason: Spelling Corrections
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,961
Likes: 2
From: Fort Knox
I found a site where a dyno test was done that showed a power increase of less than 10 when a larger TB was installed, but only withing a 1000 rpm band, IIRC 5000/6000. As I recall, it was on an engine with only bolt on mods.
One of the mags did the engine build and test and I'll try to find and post the link.
On a personal note, I've run all three, 48, 52 and 58 mm. Going from 48 to 58 showed me an acceleration increase so dramatic that I swapped it with a member for his 52.
One thing members don't seem to consider is that even though max power may not increase, the fun factor does. When moving to a larger TB, for every incremental increase in throttle opening, more air is allowed to enter the engine (when compared to a smaller TB) which causes the car to accelerate faster. Up goes the fun factor.
In the case of me running the 58, the change from a 48 was so dramatic I decided to move DOWN to a 52 to better be able to modulate the throttle and NOT blast around like Speed Racer.
Jake
One of the mags did the engine build and test and I'll try to find and post the link.
On a personal note, I've run all three, 48, 52 and 58 mm. Going from 48 to 58 showed me an acceleration increase so dramatic that I swapped it with a member for his 52.
One thing members don't seem to consider is that even though max power may not increase, the fun factor does. When moving to a larger TB, for every incremental increase in throttle opening, more air is allowed to enter the engine (when compared to a smaller TB) which causes the car to accelerate faster. Up goes the fun factor.
In the case of me running the 58, the change from a 48 was so dramatic I decided to move DOWN to a 52 to better be able to modulate the throttle and NOT blast around like Speed Racer.
Jake
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Many times guys only compare what we refer to as "peak to peak" numbers in making TB decisions. When I moved to a 58, I began a new learning curve to re-learn how to control and regulate my right foot. The same pedal pressure I had become accustomed to when using the 48 was out the window. Using that same pedal pressure, I'd blast away from stop lights and had folks looking at me like I was a drunken teenager, LOL
Sort of the same thing happens when comparing head flow numbers. Guys tend to look at and post on the max flow numbers and completely ignore all else, like port volume, mid-lift flow, bore size, etc., all of which effect how the heads will actually perform when installed on the engine.
As I recall the next biggest issue was getting the accordion to fit over the 58.
Jake
Sort of the same thing happens when comparing head flow numbers. Guys tend to look at and post on the max flow numbers and completely ignore all else, like port volume, mid-lift flow, bore size, etc., all of which effect how the heads will actually perform when installed on the engine.
As I recall the next biggest issue was getting the accordion to fit over the 58.
Jake
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
I love the throttle body threads.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
You know what would be great? If someone with access to a dyno could settle and answer these questions with finality.
Run a stock, sound L98 with stock, 52mm and 58mm throttle bodies and record RWHP.
Run a slightly modified L98 (chip, cam, porting, headers) with all three throttle bodies again and record RWHP
Run a highly modified L98 (chip, heavy cam, porting, headers, stroker, NOS or blower) with all three throttle bodies again and record RWHP
You still can't convince me that anything more than stock is needed until you start moving a lot of air.
I wish there was a comprehensive dyno run/test of all the different mods to a stock engine to see whats real and what fake!For example, is less back pressure good or bad! (no one answer this)
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
I did 58, at that time both were the same price , except with the 58 you need to mod your intake to match...
An old thread showing the importance of doing it right..
http://forums.corvetteforum.com/c4-t...plugs-ect.html
I would think the same concept would apply to the L98
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Quote 'One thing members don't seem to consider is that even though max power may not increase, the fun factor does. When moving to a larger TB, for every incremental increase in throttle opening, more air is allowed to enter the engine (when compared to a smaller TB) which causes the car to accelerate faster. Up goes the fun factor'
You could just step on the pedal faster..LOL.. Anything bigger than what you need just makes it harder to drive .. What is the point in that.
You could just step on the pedal faster..LOL.. Anything bigger than what you need just makes it harder to drive .. What is the point in that.