Big Bore Throttle Body Truth - Honda Accord Forum : V6 Performance Accord Forums
Ribbon Banner

Go Back   Honda Accord Forum : V6 Performance Accord Forums > CAR SPECIFIC DISCUSSION > 7TH GENERATION HONDA ACCORD (2003-2007) > 7G HONDA ACCORD PERFORMANCE DISCUSSION
Register FAQ Members List Calendar Mark Forums Read Insurance
V6Performance.net is the premier Honda Accord Forum on the internet. Registered Users do not see the above ads.
Like Tree10Likes
  • 1 Post By Sonnick
  • 1 Post By accord325
  • 1 Post By brian6speed
  • 1 Post By pa1nt13aller
  • 2 Post By DomGSR-T
  • 1 Post By thisaznboi88
  • 3 Post By NVA-AV6

Reply
 
LinkBack Thread Tools Display Modes
Old March 26th, 2015, 09:03 AM   #1
Registered User
 
pa1nt13aller's Avatar
 
Join Date: Mar 2014
Location: Minnesota
Posts: 497
Big Bore Throttle Body Truth

Okay...so I've been doing a lot of researching online and haven't come up with anything beneficial. I think it would be best to hear it from the people who have done the modification.

It's becoming apparent to me that a ZDX/TL/RL/MDX throttle body is completely pointless. Even Vit strongly suggests it is. That the 67IN/65OUT throttle body provides plenty of CFM. If that were true, why did honda provide the 3.5/3.7 engines with bigger throttle bodies??? What is the verdict?

EDIT: Quoted from Vit's blog:

"N/A car does NOT need a 70-80mm throttle body. Guess what, it does absolutely nothing for you. You don't gain any HP, you don't improve the car in anyway. The Skunk2/ZDX/TL TB's are for major builds (big power n/a builds need big TB's, some S/C setups benefit from big TB's -- sorry your KW kit doesn't, the Centri blower works on the same concept as a turbo).

Fun fact, we're making over 730whp with a 65mm TB. Shocked? Good.

Putting a huge TB on your car seems to be the latest trend -- it's right up there with hellaflushing."
pa1nt13aller is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old March 26th, 2015, 09:14 AM   #2
Registered User
 
05accord6spd's Avatar
 
Join Date: Feb 2012
Location: Minnesota
Posts: 424
So your saying the 3.7 tb is pointless as well as the 3.7 I'm? Or just the tb
05accord6spd is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 09:20 AM   #3
The Jester
 
Join Date: Apr 2013
Posts: 1,352
While I can't say I agree, I can't say I disagree. The mechanics of how the tb in controlled by the ECU is changed when the size is changed, or even half shafted or knife blade. If that is not compensated for or even is not possible to be retuned for and recalibrated, then big bore would in fact be a detriment.

However on larger builds, more air will of course be needed, on NA builds looking to get high rpm power focus more air will be needed. The less pressure needed to be exerted by the engine in order to suck that air in the less resistance there is pulling the air into the chamber and slowing the process of the cycle at all.

Now I do believe that slapping an 90mm on a civic is completely useless for any drivability and not worth the money for gain, I believe a minor gain such as our ZDX conversion is a minute enough change that if balanced for correctly with injectors that can keep up or a chip that can retune the sensitivity of the TPS motor can allow for some better flow when the rest of our systems are ported(most users here have either 3.2 heads or above, ported, 3.7 manifolds that weigh less than 3.0s and yet are significantly larger indicating more flow area) as long as the end goal is not to get peak power around 3k but rather into 5k as the peak maybe 5500 then allow vtec change to carry the power gain up into the 7-8k range.

Will be putting a definitive answer on this within coming time, but in the meantime I wonder if he is talking about a PSI build thats making 730 on 65? Because boosted cars usually do benefit from smaller tb,runners, even cc to an extent since they have the pressure to spare and it makes the air void created by each revolution easier to refill.
oraclem19 is offline   Reply With Quote Quick reply to this message
 
Old March 26th, 2015, 09:29 AM   #4
Registered User
 
pa1nt13aller's Avatar
 
Join Date: Mar 2014
Location: Minnesota
Posts: 497
Quote:
Originally Posted by 05accord6spd View Post
So your saying the 3.7 tb is pointless as well as the 3.7 I'm? Or just the tb
This is concerning the TB. I never said its pointless, but thats what I'm attempting to figure out.



Quote:
Originally Posted by oraclem19 View Post
While I can't say I agree, I can't say I disagree. The mechanics of how the tb in controlled by the ECU is changed when the size is changed, or even half shafted or knife blade. If that is not compensated for or even is not possible to be retuned for and recalibrated, then big bore would in fact be a detriment.

However on larger builds, more air will of course be needed, on NA builds looking to get high rpm power focus more air will be needed. The less pressure needed to be exerted by the engine in order to suck that air in the less resistance there is pulling the air into the chamber and slowing the process of the cycle at all.

Now I do believe that slapping an 90mm on a civic is completely useless for any drivability and not worth the money for gain, I believe a minor gain such as our ZDX conversion is a minute enough change that if balanced for correctly with injectors that can keep up or a chip that can retune the sensitivity of the TPS motor can allow for some better flow when the rest of our systems are ported(most users here have either 3.2 heads or above, ported, 3.7 manifolds that weigh less than 3.0s and yet are significantly larger indicating more flow area) as long as the end goal is not to get peak power around 3k but rather into 5k as the peak maybe 5500 then allow vtec change to carry the power gain up into the 7-8k range.

Will be putting a definitive answer on this within coming time, but in the meantime I wonder if he is talking about a PSI build thats making 730 on 65? Because boosted cars usually do benefit from smaller tb,runners, even cc to an extent since they have the pressure to spare and it makes the air void created by each revolution easier to refill.
Yes well stated. My power peaks around 6800rpm, so I wonder if the 3.7 throttle body, matched with the corresponding intake upgrades can keep the power going past 7k.
pa1nt13aller is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 09:52 AM   #5
Registered User
 
Sonnick's Avatar
 
Join Date: Aug 2005
Posts: 4,828
Vit s also used to the K series. Not saying he doesn't know the J, but I gained 15whp with my 3.7 setup. I guess those gains could be attributed to the manifold, but I don't know. Pretty sure ILC over at Azine reverted back to his stock TB and lost like 4whp up top. Don't quote me though.
pa1nt13aller likes this.
__________________
7.5G J30 6spd -- 13.28 @107.56
Full Bolt ons/Street Tune/3.94 Final Drive
Instagram = j30_allmotor
Sonnick is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 10:12 AM   #6
Registered User
 
accord325's Avatar
 
Join Date: Jul 2012
Location: Tampa
Posts: 2,392
You should ask how VIT is making 730WHP. They are cramming a **** load of air through the TB by boost. N/A doesnt have that option so you need as large as an opening as possible. Larger IM and TB do indeed yield gains on N/A J's
pa1nt13aller likes this.
accord325 is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 10:21 AM   #7
Registered User
 
07J30's Avatar
 
Join Date: Apr 2014
Location: Ohio
Posts: 429
im going to be purchasing all the parts for a 3.7 IM/spacer/runners all pnp with a ZDX TB VERY SOON...Im interested to see what the others who have this setup think about its gains, i dont wana throw money away, but the evidence seems to be there showing these mods do in fact yield gains.
__________________
AGENT J: full bolt on j36 hand built by myself and tuned at slowmotion motorsports 295WHP/275WTQ
07J30 is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 10:23 AM   #8
Registered User
 
Sonnick's Avatar
 
Join Date: Aug 2005
Posts: 4,828
I made up 3+ cars on the street from 40-120 with the addition of these mods, ported runners and an upgraded 4" intake over my AEM. Perfect dyno would be back to back stock TB and 3.7 TB with the 3.7 manifold. Would need the adapter to use the stock TB on 3.7 manifold though.

However, pa1ntballer is specifically talking about the TB, not the manifold itself. So I can't speak specifically about the TB gains.
__________________
7.5G J30 6spd -- 13.28 @107.56
Full Bolt ons/Street Tune/3.94 Final Drive
Instagram = j30_allmotor
Sonnick is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 10:31 AM   #9
Registered User
 
accord325's Avatar
 
Join Date: Jul 2012
Location: Tampa
Posts: 2,392
ekkkk.... why upgrade to a larger TB if your IM has the same volume?
accord325 is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 03:14 PM   #10
J35 _ 5-Speed A/T
 
WHEEELMAN's Avatar
 
Join Date: Dec 2003
Location: GA
Posts: 1,736
Quote:
Originally Posted by pa1nt13aller View Post
EDIT: Quoted from Vit's blog:

"N/A car does NOT need a 70-80mm throttle body. Guess what, it does absolutely nothing for you. You don't gain any HP, you don't improve the car in anyway.
Clarification = on a OEM N/A engine, no porting, piggyback tuning, etc. A bigger throttle body, IN GENERAL, will have little to no effect.

The engine will only use what volume of air it is currently set up to use.





Quote:
Originally Posted by pa1nt13aller View Post
EDIT: Quoted from Vit's blog:

"The Skunk2/ZDX/TL TB's are for major builds (big power n/a builds need big TB's"

Clarification - I would define a MAJOR build as 11:1 or higher compression, Head/Cam package(such as T/B Motorworx Full Race head and billet cams), fabricated intake manifold, BIG A$$ throttle body and a full standalone.

This set up would benefit from a bigger throttle body because you have opened up the top end and the low end has the high compression to use the volume of air and fuel being forced into the combustion chambers.


As an example, Mr. Smalser can fabricate a dual throttle body set up. On a STOCK J30 versus a MILD build J30, the mild build J30 would see more benefit from a dual T/B.

So, if you are asking about throwing ONLY a bigger T/B on your stock J30, you might see some gain, or maybe not.


However, if you port the heads and throw on a 3.7 intake manifold you have opened up the Top End to "breath" better. The engine will now use the increased volume of air much better versus a stock engine with ONLY a bigger throttle body.


Got it?...or got milk?
WHEEELMAN is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 03:21 PM   #11
Registered User
 
thisaznboi88's Avatar
 
Join Date: Dec 2007
Location: West Virginia
Posts: 8,733
you can buy my TB and send your to get ported. Then tell us if you make any power after?

maxbore will do it for 100 bucks. 65->68mm
thisaznboi88 is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 05:22 PM   #12
Registered User
 
accord325's Avatar
 
Join Date: Jul 2012
Location: Tampa
Posts: 2,392
I gained 30whp from DTB, ported runners, and a J Pipe (or CBE, cant remember which) and have the Dyno to prove it. I went from 214whp to 244whp, untuned. just saying........
accord325 is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 05:38 PM   #13
Registered User
 
Join Date: Jun 2010
Posts: 155
A larger TB will make power if the TB is a restriction. You need to modify both intake and exhaust.

You don't want to go too big.

On my j32a2 setup, I think 74 or 76 MM will be perfect.
Sonnick likes this.
brian6speed is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 06:11 PM   #14
Registered User
 
Sonnick's Avatar
 
Join Date: Aug 2005
Posts: 4,828
^ Yep. If you have all exhaust mods and no intake mods, you will make vood power from just a CAI, and vice versa. Perfect example: I gained 25+WHP from my cutout over my stock exhaust. That's taking into account all of my intake mods, PCDs & Jpipe "exiting" into a stock catback. Obviously it was a huge restriction.

Same is true for the intake. That's probably why I gained 15whp from this setup. Had I been stock, I guarantee my gains would have been far less. The correct combination of mods is very important.

Pa1ntballer, how is the car btw? Did you ever dyno after your build?
__________________
7.5G J30 6spd -- 13.28 @107.56
Full Bolt ons/Street Tune/3.94 Final Drive
Instagram = j30_allmotor
Sonnick is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 06:40 PM   #15
Registered User
 
pa1nt13aller's Avatar
 
Join Date: Mar 2014
Location: Minnesota
Posts: 497
Good replies .

And sonnick my car is doing well. Although my head gaskets went out on me about a month ago lol. My own fault....didn't torque the head bolts correctly...had to tear it down in my non heated garage while it was 0-15 degrees outside....was not fun. Just installed the Acura rl manifold and got the 3.7 throttle body on the way. I can now spin the tires while shifting to 3rd gear .

I've tried all local shops for a dyno and all of em are booked until May or rent it out, and Idk how to use a dyno or strap it in....I'm honestly trying to get it dyno'd trust me. It's complicated
accord325 likes this.
pa1nt13aller is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 07:02 PM   #16
Registered User
 
Join Date: May 2011
Posts: 65
As for me, on my 08TL-S I have gained 6whp from the ZDX TB alone. Same gain that ILC from azine got from the ZDX TB and 3.7IM. So the 3.7IM on a TL-S is useless whp wise. My test was done within 20 minutes or so intervals as a stock vs ZDX TB dyno test. My dyno results are posted on azine if you want to see them. I have done a lot of same day before and after tests that are available, just look if interested...
Sonnick and pa1nt13aller like this.
DomGSR-T is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 07:07 PM   #17
Registered User
 
pa1nt13aller's Avatar
 
Join Date: Mar 2014
Location: Minnesota
Posts: 497
Don't you need a retune after installing a bigger throttle body? I'm trying to get Vit to retune mine when I install the throttle body but it's frustrating how slow he responds...2 cals a week.

DomGSR-T don't you tune as well? E tuning?
pa1nt13aller is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 07:47 PM   #18
Registered User
 
Join Date: May 2011
Posts: 65
Quote:
Originally Posted by pa1nt13aller View Post
Don't you need a retune after installing a bigger throttle body? I'm trying to get Vit to retune mine when I install the throttle body but it's frustrating how slow he responds...2 cals a week.

DomGSR-T don't you tune as well? E tuning?
Yes that's me And there will be very small difference from the TB so retuning would be minimal...

Last edited by DomGSR-T; March 26th, 2015 at 07:50 PM.. Reason: added info
DomGSR-T is offline   Reply With Quote Quick reply to this message
Old March 26th, 2015, 08:08 PM   #19
Registered User
 
thisaznboi88's Avatar
 
Join Date: Dec 2007
Location: West Virginia
Posts: 8,733
^ Dom been giving me one/day which is freaken awesome.
pa1nt13aller likes this.
thisaznboi88 is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 12:10 AM   #20
Registered User
 
Join Date: Dec 2007
Posts: 516
its all good. my j35a8 hybrid runs well. pulls like a mofo
qaz393 is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 01:03 AM   #21
Registered User
 
Join Date: Jun 2010
Posts: 155
What size in MM is the ZDX TB?

From what I have seen, the only difference from 3.5 IM to a 3.7 IM is the neck area where the TB mounts is wider. The TB would need to atleast be 74 MM or larger for the switch in manifolds to be worth it.

For the dynos you did with the 3.7 IM did you open up the lower ports or anything?

Even with the 3.7 IM, the IM can be a restriction. For my j32a2, the oem 3.2 IM has more power potential than 3.7 IM. Custom could be even better if designed properly.
brian6speed is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 01:14 AM   #22
Registered User
 
Join Date: Jun 2010
Posts: 155
I just read the ZDX TB is only 69 MM. That is smaller than my bored 3.2 TB. That is probably why you don't see much gain from 3.7 IM. Only difference is TB neck size area. 3.7 IM neck is 74 to 76 MM wide.

If you bored out the ZDX TB or had another larger option then the 3.7 IM might show gains.
brian6speed is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 02:27 AM   #23
Registered User
 
Sonnick's Avatar
 
Join Date: Aug 2005
Posts: 4,828
Quote:
Originally Posted by brian6speed View Post
I just read the ZDX TB is only 69 MM. That is smaller than my bored 3.2 TB. That is probably why you don't see much gain from 3.7 IM. Only difference is TB neck size area. 3.7 IM neck is 74 to 76 MM wide.

If you bored out the ZDX TB or had another larger option then the 3.7 IM might show gains.
It's 69mm on the manifold side, 79 on the intake side. Either way it will make power because it's larger than a bored stock TB. Pretty sure the larger a stock TB gets is 67 or 68mm on th manifold side. According to Acur, there's something like a 6 or 7% flow increase from the TB alone. Mine is bored to 81/72 I believe. The 3.7 manifold opening is either 75 or 76mm, so it would be better to have a 76mm throttle body like you were saying. Problem is, I don't believe there is J series DBW that large on the manifold side.
__________________
7.5G J30 6spd -- 13.28 @107.56
Full Bolt ons/Street Tune/3.94 Final Drive
Instagram = j30_allmotor
Sonnick is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 04:56 AM   #24
M90SC Boosting 13PSI
 
NVA-AV6's Avatar
 
Join Date: Apr 2007
Location: Northern Virginia
Posts: 10,960
After reading this thread there was only one person on here who stated it correctly. ANY MOD has to have the supporting mods in place to get full effect. Induction and exhaust have to work together to get value from all the various mods, it has to be done in a holistic approach from the filter to the tail pipe, any restriction can cause other mods to not have their potential effect or even cause poor running and power loss.

As far as forced induction, free flow exhaust is important to keep from excessive back pressure build up in the exhaust and engine damage, but the intake side really is not all that important as you are stuffing the air in which will cover many sins. Now a good induction setup will of course help you get into boost much faster.
Sonnick, simione and thisaznboi88 like this.
NVA-AV6 is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 07:16 AM   #25
Registered User
 
Join Date: Jun 2010
Posts: 155
Nice post Paul. You said it better.

My 3.2 oem TB is bored to 70 MM on manifold side. Your 72 MM isn't bad, but makes 3.7 IM not worth it over the 3.5 in my opinion.
brian6speed is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 08:47 AM   #26
Registered User
 
05accord6spd's Avatar
 
Join Date: Feb 2012
Location: Minnesota
Posts: 424
Some one really was arguing that a 3.7 tb on stock Im and runners isn't going to show gains? I thought that was fairly obvious? Who would even make an adapter for that. And zdx and MDX are the same tb same part number same size.
Basically comes Down to what tb you get at what price + porting price, my zdx was 99$ used so 100$ to port is nothing.

Last edited by 05accord6spd; March 27th, 2015 at 08:48 AM..
05accord6spd is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 01:12 PM   #27
Registered User
 
Sonnick's Avatar
 
Join Date: Aug 2005
Posts: 4,828
Quote:
Originally Posted by brian6speed View Post
Nice post Paul. You said it better.

My 3.2 oem TB is bored to 70 MM on manifold side. Your 72 MM isn't bad, but makes 3.7 IM not worth it over the 3.5 in my opinion.
If I'm not mistaken, the 3.5 manifold has a 68mm opening, which would cause turbulence with a 72mm throttle body.

I don't know enough about the internals of the manifold to say that there are any differences, but the larger opening has surely proven to make power with the right supplemental mods. Port matching is also key, IMO, so that everything flows smoothly. You don't want any lips that would cause turbulence.
__________________
7.5G J30 6spd -- 13.28 @107.56
Full Bolt ons/Street Tune/3.94 Final Drive
Instagram = j30_allmotor
Sonnick is offline   Reply With Quote Quick reply to this message
Old March 27th, 2015, 01:57 PM   #28
Registered User
 
Join Date: May 2011
Posts: 65
Quote:
Originally Posted by Sonnick View Post
If I'm not mistaken, the 3.5 manifold has a 68mm opening, which would cause turbulence with a 72mm throttle body.

I don't know enough about the internals of the manifold to say that there are any differences, but the larger opening has surely proven to make power with the right supplemental mods. Port matching is also key, IMO, so that everything flows smoothly. You don't want any lips that would cause turbulence.
Of course the 3.5IM need to be bore/grind to match the opening of the larger TB. And I think the stock 3.5IM is 2mm larger than the stock 64mm tb so it's 66mm.
DomGSR-T is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply


Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Honda Accord Forum : V6 Performance Accord Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Chapter
Choose your AV6 Chapter Location
Ride
What do you drive?
Insurance
Please select your insurance company (Optional)

Log-in


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On