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Old 01-07-2019, 02:02 PM   #1
Zombie Panda
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Default To DBW or not to DBW that is the question

I have a 2003 WRX. Currently using a RMR 90mm drive by cable throttlebody. The intake manifold I was using (emphasis on 'was') had provisions for the stock IACV. The new intake manifold does not.

So I have 3 options for idle control:
1) Design/machine a block so the stock IACV can be used.
PROS: Uses stock IACV so wiring tuning will be easier. Uses my current throttlebody.
CONS: Have to design and machine a part, have to find a location to mount it, no traction control option like DBW

2) Use an aftermarket IACV that already has remote-mount blocks available (GM/Ford/etc.)
PROS: Mounting block readily available, IACV's are cheap and available everywhere. Uses my current throttlebody.
CONS: Have to figure out wiring, have to find a location to mount it, no traction control option like DBW

3) Convert to DBW
PROS: Cleaner install - no remote mounted IACVs, Traction control options
CONS: Have to buy a DBW throttlebody large enough for my HP goals, have to buy a DBW pedal assembly, have to figure out wiring, more complicated to tune/setup

I'm using a Haltech Elite 2500 so making any scenario work isn't terribly difficult.


After searching, I've only found threads where someone was trying to install a DBW engine swap into an older chassis. Several folks in those threads were against using DBW but didn't give a reason. ("DBW sucks bro") They were older threads also so DBW was kinda new then.

Thanks in advance
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Old 01-08-2019, 12:18 PM   #2
subydude
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Just curious, why such a large TB? 90mm is pretty huge for us and without a matching IM and intercooler piping it's likely not doing too much.

The DBW conversion also requires a pedal change and some other conversion pieces. I'm actually doing the same conversion to my GC also using a Haltech 2500. I'm going to make my own conversion pieces though and use the OEM TB since I'm not going to make more than 500 hp.
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Old 01-08-2019, 04:57 PM   #3
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Quote:
Originally Posted by Zombie Panda View Post
I have a 2003 WRX. Currently using a RMR 90mm drive by cable throttlebody. The intake manifold I was using (emphasis on 'was') had provisions for the stock IACV. The new intake manifold does not.

So I have 3 options for idle control:
1) Design/machine a block so the stock IACV can be used.
PROS: Uses stock IACV so wiring tuning will be easier. Uses my current throttlebody.
CONS: Have to design and machine a part, have to find a location to mount it, no traction control option like DBW

2) Use an aftermarket IACV that already has remote-mount blocks available (GM/Ford/etc.)
PROS: Mounting block readily available, IACV's are cheap and available everywhere. Uses my current throttlebody.
CONS: Have to figure out wiring, have to find a location to mount it, no traction control option like DBW

3) Convert to DBW
PROS: Cleaner install - no remote mounted IACVs, Traction control options
CONS: Have to buy a DBW throttlebody large enough for my HP goals, have to buy a DBW pedal assembly, have to figure out wiring, more complicated to tune/setup

I'm using a Haltech Elite 2500 so making any scenario work isn't terribly difficult.


After searching, I've only found threads where someone was trying to install a DBW engine swap into an older chassis. Several folks in those threads were against using DBW but didn't give a reason. ("DBW sucks bro") They were older threads also so DBW was kinda new then.

Thanks in advance

They likely dislike the lack of instant response a DBW has in comparison to the feeling on a cable throttle. That being said, you can tune a DBW set-up to work with the same responsiveness as a cable throttle.

Personally given the information provided I would go with option #1. That way you get to keep that massive throttle body (never heard of one that large on a Subaru) and making the "block" or "plate" to allow the factory IACV to be used would actually be extremely easy to fabricate.
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Old 01-09-2019, 09:42 AM   #4
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Quote:
Originally Posted by subydude View Post
Just curious, why such a large TB? 90mm is pretty huge for us and without a matching IM and intercooler piping it's likely not doing too much.

...
I have matching intake manifold and intercooler piping.

Quote:
Originally Posted by Scuby04STi View Post
They likely dislike the lack of instant response a DBW has in comparison to the feeling on a cable throttle. That being said, you can tune a DBW set-up to work with the same responsiveness as a cable throttle.

Personally given the information provided I would go with option #1. That way you get to keep that massive throttle body (never heard of one that large on a Subaru) and making the "block" or "plate" to allow the factory IACV to be used would actually be extremely easy to fabricate.
There aren't many people that venture out past about 75mm on t-body size. Possibly due to intake manifold restrictions or whatever. I could run a 75mm without impacting my HP goals too badly. If I go to DBW, I will likely get a 75mm just because of availability - but there are 2 good reasons why I'm using the RMR 90mm... 1) The worksheet that I got from Shane Tecklenburg (Tuned by Shane T) says I need a 84.6mm diameter throttlebody for 750hp, and 2) I already had the 90mm RMR throttlebody and it's a really nice piece. I ordered it for a customer's Supra and he changed his mind so I ended up using it.

Last edited by Zombie Panda; 01-09-2019 at 09:49 AM.
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Old 01-09-2019, 02:17 PM   #5
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Frankly, having tuned DBW throttles on a standalone now, I wouldn't go back. There are nothing but downsides with a cable throttle:

1. Broken cables
2. Linear response (only)
3. IACV replacement cost
4. Rotational idle requirement for anti-lag (yeah, I know it sounds cool, though)
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Old 01-10-2019, 02:22 PM   #6
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Quote:
Originally Posted by mrsaturn7085 View Post
Frankly, having tuned DBW throttles on a standalone now, I wouldn't go back. There are nothing but downsides with a cable throttle:

1. Broken cables
2. Linear response (only)
3. IACV replacement cost
4. Rotational idle requirement for anti-lag (yeah, I know it sounds cool, though)
Thanks for the info.

The more I dig into this, the more I see the only real downsides are financial investment and added complexity. Both of which are not that big of a deal.

Unless I come across new information that changes my mind, I'm leaning heavily towards converting to DBW.
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Old 01-10-2019, 03:25 PM   #7
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Just cover your ass in terms of safety. Follow the standalone instructions to a 'tee' and be aware that ALL standalone DBW control sidesteps some of the safety considerations made in factory DBW systems.
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Old 01-10-2019, 08:35 PM   #8
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What manifold are you switching to? There is a spacer that kS tech makes http://www.kstech.biz/subaru-wrx-thr...fold-3-4-19mm/ I've had it on mine since I switched to a Cosworth mani. The design is different that the pic and works great.
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Old 01-20-2019, 11:33 AM   #9
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90mm TB ? You shooting for 2000+ ?
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Old 01-20-2019, 11:39 AM   #10
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Quote:
Originally Posted by mrsaturn7085 View Post
Just cover your ass in terms of safety. Follow the standalone instructions to a 'tee' and be aware that ALL standalone DBW control sidesteps some of the safety considerations made in factory DBW systems.
Any good system will still have very good failsafes if the tuner chooses to use them all.

For most part as long as both tracks on the blade behave as expected ( likewise pedal sensor ), and pedal vs blade stay within tight ( user set however ) parameters, then all should be well. Any deviation from that should force either a limp or shutdown until rectified.

Although I was a little cautious when I moved to non factory DBW myself a couple of years ago, but really I can see almost no downsides.
It just works, and gives the user more options.
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Old 01-20-2019, 11:30 PM   #11
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Quote:
Originally Posted by stevieturbo View Post
Any good system will still have very good failsafes if the tuner chooses to use them all.

For most part as long as both tracks on the blade behave as expected ( likewise pedal sensor ), and pedal vs blade stay within tight ( user set however ) parameters, then all should be well. Any deviation from that should force either a limp or shutdown until rectified.

Although I was a little cautious when I moved to non factory DBW myself a couple of years ago, but really I can see almost no downsides.
It just works, and gives the user more options.
Define 'good'. Most motorsport controls I've used will allow you to burn the throttle motor up in less than a minute if you program it poorly and none had a limp mode.
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Old 01-21-2019, 03:05 AM   #12
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Will your ECU do rev-matched downshifts with a DBW throttle body? If yes, I'd probably let that be the deciding factor.
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Old 01-21-2019, 01:25 PM   #13
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Quote:
Originally Posted by mrsaturn7085 View Post
Define 'good'. Most motorsport controls I've used will allow you to burn the throttle motor up in less than a minute if you program it poorly and none had a limp mode.
Well a bad tuner/user can **** almost anything up, no matter how "good" the hardware/software is.
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Old 01-22-2019, 06:30 PM   #14
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Quote:
Originally Posted by mrsaturn7085 View Post
Frankly, having tuned DBW throttles on a standalone now, I wouldn't go back. There are nothing but downsides with a cable throttle:

1. Broken cables
2. Linear response (only)
3. IACV replacement cost
4. Rotational idle requirement for anti-lag (yeah, I know it sounds cool, though)
My thoughts. DBW only has advantages.

On the ALS, I was never a carberry junky but always wondered why no one (that I'd seen) rigged the cruise control to kick the TB plate. Everyone mechanically set or ran air solenoids.
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Old 01-22-2019, 08:30 PM   #15
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Because cyclic idle sounds amazing.
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Old 01-28-2019, 11:40 AM   #16
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Yeah, it does sound bitchin. Everyone wants that Group A sound
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