Throttle body swaps

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Hondata
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Throttle body swaps

Post by Hondata » Tue May 05, 2015 12:12 pm

Since people often swap to larger drive by wire throttle bodies, we tested Civic Si, TL Type S and ZDX throttle bodies for compatibility.

There are two types of drive by wire systems that Honda uses. One where the ECU drives the throttle body directly (Civic, TL, RDX) and where there is a separate throttle controller (S2000, TSX before 2007).

ECU driving the throttle body directly.
throttle-civicsi.png
throttle-civicsi.png (13.76 KiB) Viewed 9634 times
ECU communicating with the throttle controller.
throttle-tsx.png
throttle-tsx.png (30.88 KiB) Viewed 9634 times
All throttle bodies have two components - a DC motor to position the throttle plate, and a throttle position sensor to determine where the throttle plate is. The throttle position sensor has two resistive elements (A & B) for multiple redundancy. The motor is driven both open and closed by the ECU or controller, switching voltage across the motor using two sets of transistors.

Tests - Throttle Position Sensors

1. TPS A & B voltage
A. Civic Si
Closed 0.60 / 1.48 volts
Default position 0.85 / 1.67 volts
Open 4.00 / 4.20 volts
B. TL-S
Closed 0.62 / 1.50 volts
Default position 0.89 / 1.72 volts
Open 3.85 / 4.07 volts
C. ZDX
Closed 0.60 / 1.47 volts
Default position 0.90 / 1.72 volts
Open 3.97 / 4.17 volts

2. Throttle plate position
A. Civic Si
Closed 0.1%
Default position 7.8%
Open 105%
B. TL-S
Closed 0.0%
Default position 9.1%
Open 100.3%
C. ZDX
Closed 0.1%
Default position 9.5%
Open 102.6%

The TPS sensor for each throttle body works in the same way. The default position is different for the TL & ZDX throttle bodies.

Tests - Motor

1. Motor resistance
Averaged over 6 measurements, open direction and closed direction, using actual current for set voltage
A. Civic Si 2.85 ohms
B. TL-S 1.70 ohms
C. ZDX 1.35 ohms

2. Peak current @ 14V
A. Civic Si 4.9 amps
B. TL-S 8.2 amps
C. ZDX 10.4 amps

As the throttle body gets larger, the motors are higher torque / higher current. This is not proportionate to the throttle body opening area, as the ZDX throttle draws almost twice the current of the Civic throttle body.

Under real world conditions the throttle controller will vary the current to the motor in order to position the throttle plate. The current required to do this will be around the same for each throttle body (roughly 1 amp). However, the peak current is much higher on the larger throttle bodies. This is likely to be a problem if the transistors in the throttle controller shut down from over current or over temperature.

With the Civic Si / R18 ECU, the throttle controller uses a IC chip to drive the throttle body motor. The IC is rated at 5.0 amps continuous current, and has over current and over temperature shut downs. Switching to a throttle body which uses more than double the current is likely to overload the controlling IC.

Conclusion

Bigger throttle bodies draw more current, potentially overheating the controlling circuitry, causing erratic throttle operation and errors. This cannot be fixed by software.
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VitViper
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Re: Throttle body swaps

Post by VitViper » Tue May 05, 2015 12:29 pm

Good info. Would be interesting to see the results for the TSX TB (07-08) as that's the one I was having problems with, maybe I'll get bored and take a look at it.

However, what you just posted will go over 99% of your consumer's heads, and they will continue putting on the big TB's to make 2hp on their 200hp bolt on cars.

lol

D-Rob
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Re: Throttle body swaps

Post by D-Rob » Wed May 06, 2015 5:27 am

VitViper wrote:Good info. Would be interesting to see the results for the TSX TB (07-08) as that's the one I was having problems with, maybe I'll get bored and take a look at it.

However, what you just posted will go over 99% of your consumer's heads, and they will continue putting on the big TB's to make 2hp on their 200hp bolt on cars.

lol
This is the most true statement ever.

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Hondata
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Re: Throttle body swaps

Post by Hondata » Wed May 06, 2015 7:45 am

The point is now the customer can see why it is not a simple software change to support different throttle bodies.
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VitViper
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Re: Throttle body swaps

Post by VitViper » Wed May 06, 2015 12:28 pm

The CEL "fix" is going a long way, it's doing the trick for now.

A certain someone I know has adapted Lexus and Toyota big TB's to work on our cars with no issues, it was quite a bit of work the first time around ;)

DomGSR-T
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Re: Throttle body swaps

Post by DomGSR-T » Thu May 07, 2015 3:49 pm

Are the TPS A & B voltage and Throttle plate position values taken from a HDS? IF yes I will check mine to make sure I have the same. Thanks for the reply!

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Re: Throttle body swaps

Post by Hondata » Thu May 07, 2015 4:09 pm

I have not tested with the HDS. The voltages & positions may be different.
In any case I do not think the TPS is the problem.
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DomGSR-T
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Re: Throttle body swaps

Post by DomGSR-T » Mon May 11, 2015 12:25 am

Hondata wrote:I have not tested with the HDS. The voltages & positions may be different.
In any case I do not think the TPS is the problem.
Just tested with the HDS and it's the exact same value your have listed

shind3
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Re: Throttle body swaps

Post by shind3 » Mon May 11, 2015 11:58 am

Cool. Now how about similar measurements for systems with a separate throttle controller? :D

I'd like to measure mine and compare for purposes of diagnosis.


Also, how did you measure 'peak' current? Did you mechanically limit travel while actuating the pedal? Or is it actually a measure of inrush current when opening the throttle quickly?

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Re: Throttle body swaps

Post by Hondata » Mon May 11, 2015 1:50 pm

The measurements for the TB will be the same regardless of the controller. If you want to open up the S2000 controller and read the IC part number for the output then you can find the current limit for the S2000 controller. But, it is moot as the TB motors are different unless the S2000 controller is much higher current than the Civic/RDX etc.
Peak current is just what the TB motor uses at max torque. In use, most of the time the motor is only using about 1 amp to stay in position.
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mabo
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Re: Throttle body swaps

Post by mabo » Tue Jun 02, 2015 12:07 pm

Ok, so once we retrofit 04-05 TSX with flashpro compatible 07-08 TSX ECU we need to change wiring as well ? How it works then if prefacelift cars

has TB controller and facelift ECU use direct control method ?

BoostedK
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Re: Throttle body swaps

Post by BoostedK » Sat Mar 12, 2016 6:19 pm

Where is the IC here? This is from the s2000, 06-08 TSX DBW driver.
image.jpeg
image.jpeg (2.72 MiB) Viewed 7963 times
If it is the big square chip here is the best I can do photography wise. It has some potting compound on it making it nearly illegible. I tried searching but didn't find any info.
Attachments
image.jpeg
image.jpeg (1.85 MiB) Viewed 7951 times

peteyj88
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Re: Throttle body swaps

Post by peteyj88 » Tue Nov 15, 2016 5:58 pm

Hondata wrote:The measurements for the TB will be the same regardless of the controller. If you want to open up the S2000 controller and read the IC part number for the output then you can find the current limit for the S2000 controller. But, it is moot as the TB motors are different unless the S2000 controller is much higher current than the Civic/RDX etc.
Peak current is just what the TB motor uses at max torque. In use, most of the time the motor is only using about 1 amp to stay in position.
Hi, sorry to bring this topic back from the dead. I guess no one ever posted the results for the S2000? I'm curious as to the results of this test. Have you or anyone you know ever run into an issue with these controller units by using larger throttle bodies? I'm trying to pick my second S, my first one was an '04. I'm trying to decide if the new one should be a mechanical or DBW car. Do you by chance have the test result numbers for the S2000's controller? I'm trying to draw a conclusion from what you posted. If I were to stroke a DBW S2000 to the point where a larger throttle body could be beneficial to take advantage of the extra cubes, this may put stress on the transistors of the controller according to your post. Based on this premise then, ideal cars to stroke and potentially FI are older '00-'05 since they don't have this "problem?"

I'm wondering if, since the S2000 is the more "intense/sportier" car compared to the others you mentioned, if Honda built a higher level of tolerance on those transistors? Again, do you have any test numbers you can share about the S's controller unit?

Gernby
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Re: Throttle body swaps

Post by Gernby » Mon Nov 21, 2016 9:21 am

The '06+ S2000 already has a larger diameter throttle body than the '00-'05, which is about the same diameter as the older TB's after having them re-bored to their largest possible diameter. Also, the OEM actuator is strong enough to drive 4 60mm ITB's over 20K+ daily-driven miles without any failures.
'06 NFR S2000

peteyj88
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Re: Throttle body swaps

Post by peteyj88 » Fri Nov 25, 2016 7:01 pm

Gernby wrote:The '06+ S2000 already has a larger diameter throttle body than the '00-'05, which is about the same diameter as the older TB's after having them re-bored to their largest possible diameter. Also, the OEM actuator is strong enough to drive 4 60mm ITB's over 20K+ daily-driven miles without any failures.
Cool! Thanks for the info. I figured this would be the case. Then is it likely that the numbers and tests ran on this thread are a bunch of smoke? I'm not doubting Hondata's knowledge about this one bit nor do I think they wasted their time on these tests, actually on the contrary I think it's very useful info as a sort of gauge but I can't help but wonder. If these tests claim a potential overheat from using ONE larger throttle body, then surely 4 would be overkill and according to their evidence should easily fry the DBW throttle controller? So again back to my original point, was this whole testing thing kind of.......a waste? Or maybe only specifically applied to all other Honda DBW applications?

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