HOYS' ST185 Res-Q

Alikazam

Member
abeans":22nvlg4u said:
One of my favorite things about older cars is drive by cable. :(

There is a definite smiplicty and elegance to just putting your foot down and moving the throttle blade directly. That being said, almost all new cars use drive by wire and with modern aftermarket ECU's and some retro-fitting, you can do things like add cruise control ability with just the computer brain and some algorithms without all the mechanical hardware, etc. by having a drive by wire throttle body set up. How cool would it be to have cruise control on a 1971 cuda or 1969 charger without any additional cables? Anyway, I digress :)
 

autojumbled

New member
Interested to see how you get on with the electronic throttle - I agree. Updating to newer tech is a great way to ensure older cars stay usable! :D
 

underscore

Well-known member
Surely you'll miss having that big looping mess across the top of the engine. I suppose you could run the DBW harness the same way to keep the look :p

I love the forum hopping to find the info you need to do something unconventional. Sifting through the tidbits to figure out if X fits Y, and Y fits Z with a tweak, then it should fit my car is a lot of fun.

I imagine most of the dislike of DBW comes from early systems that I assume had a bit of a delay. I never noticed anything in my wifes old Matrix though, my only annoyance with it was trying to adjust the idle and I assume that's a non-issue with an aftermarket ECU.
 

hoys

Member
underscore":31av1auu said:
I imagine most of the dislike of DBW comes from early systems that I assume had a bit of a delay. I never noticed anything in my wifes old Matrix though, my only annoyance with it was trying to adjust the idle and I assume that's a non-issue with an aftermarket ECU.

Exactly, even modern systems have a built in delay. With an aftermarket ECU you can define all parameters. Believe it or not, a DBW system can move a throttle plate faster than a cable.

All of the parts are on order or on hand for the conversion. I'm attempting to use the Rat2 MR2 DBW pedal adapter, but I assume I'll have to make my own, but it's a good starting point.

I also desinged and ordered a throttle adapter plate to deal with the IAC channel in the manifold and the fact that the DBW throttle doesn't have this. This adapter should also alleviate a small spacing issue of the DBW motor housing to the cold start injector to IAT adapter plate. Small grinding might need to occur, but should be pretty straight forward.

The Ford TB selected has smaller bolt holes than the 3S manifold so the holes need to be drilled a size bigger, but no problem there.

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grip-addict

Active member
Any chance you came across any that fit the gen 3 factory intake manifold?
I'm also in the DBW is better camp, but clearly we are outliers within the 3sgte community.
 

hoys

Member
grip-addict":2d1l2xkp said:
Any chance you came across any that fit the gen 3 factory intake manifold?
I'm also in the DBW is better camp, but clearly we are outliers within the 3sgte community.

Do you know the dimensions of the gen3 TB? Bolt pattern and blade size?

There is a good chance there is a bosch motorsports TB available:

https://www.bosch-motorsport.com/conten ... e_Body.pdf

I found the match as noted above by a lot of forum surfing. I also used photoshop to take the factory gasket and line it up in Photoshop with pictures of the throttle body.
 

grip-addict

Active member
Gen 3 Id is 60 mm. The bolts are 72 mm center to center.
I've looked at them in the past but I think an adapter plate would need to be made to fit the 60 or 68mm bosch tb to the intake flange. I don't mean to thread jack tho, was just wondering if you saw anything drop in :)

Definitely curious to see how you handle the pedal part, too.
Thanks
 

hoys

Member
TB is back from getting the mounting holes enlarged. Here are pictures roughly mounted with an adapter plate I had made to allow for the normal gasket to seal to the manifold and a custom gasket to seal the TB. The OE gasket is on the wrong side of the adapter in the picture, but you get the idea.

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grip-addict

Active member
that fits very nicely!
I'm curious to see what the adapter plate looks like, did you have to add a ridge/inset to seal the channel from the IAC?
Also, do you have a mill? Jealous if so :notworthy:
 

hoys

Member
grip-addict":1pg9cyxi said:
that fits very nicely!
I'm curious to see what the adapter plate looks like, did you have to add a ridge/inset to seal the channel from the IAC?
Also, do you have a mill? Jealous if so :notworthy:

The adapter plate is essentially just a flat plate of aluminum that covers the entirety of the stock gasket. No inset etc for the IAC, just blocking it off. Not "optimal" but it works. I just ordered the plates from a laser cutting place online. Easy and cheap, like 30 bucks shipped for four of them. I ordered 1/8th inch aluminum which might not be enough, but I can double stack them.
 

Alikazam

Member
Looks like there is a lip inside? Might need to see about cutting that out or grinding to make it open up to the TB actual opening size. As for gasket, you might look at some of the DIY gasket material to cut out a gasket that blocks the factory IAC opening part and has the right opening for the TB. Looks good! :)
 

hoys

Member
Alikazam":231upho6 said:
Looks like there is a lip inside? Might need to see about cutting that out or grinding to make it open up to the TB actual opening size. As for gasket, you might look at some of the DIY gasket material to cut out a gasket that blocks the factory IAC opening part and has the right opening for the TB. Looks good! :)

Getting the manifold ported would certainly be ideal. I'm really just preparing the rest of the car for future plans when the stock engine bites the dust. Getting all the features of the ECU up and running on this engine is mainly just a testbed.

The adapter plate I made will block off the factory IAC opening section with the factory gasket and then the DBW TB will seal to the adapter plate.
 
I was told that there is a Lexus sold in Europe that has a fly by wire throttle body that fits 3sgte directly. The idea was to get a dog gear kit with sequential shifter adapter from SQS. I am told they work well. That combined with drive by wire throttle will allow programing of flat shift ECU function like you have in sequential transmission application. I want to try that in my rally car. Somebody did it on a ST205 rally car there. Worked well.
 

hoys

Member
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Throttle body fully mounted. I needed to stack two of my adapter plates to space it correctly. If I was a stickler I'd reorder the plates in a thicker aluminum, but this will work fine.

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This is what the plate looks like from the manifold side with a new gasket:

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I also designed and printed a custom DBW pedal adapter.

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The pedal is a touch too far away from the brake pedal, but I can worry about that later, just trying to get this boy on the road soon.

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Next up: Wiring the throttle pedal and throttle body to the ECU
 

hoys

Member
Update!

Got a lot of little things buttoned up and the car moving on its own again. Needless to say, very happy!

Just a few images I've taken, not everything done is captured.

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Got the FPR bracket professionally 3D printed in a CF infused material. Rated for something like 180C* so it should hold up well to underhood temps. Making it out of metal was too costly. About 40 dollars for the part. Front part is the professionally printed, rear is my prototype PETG print (which was already broken!)

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The engine bay almost all put back together. Had a fitting welded to the intake side of the AWIC as the GTX 2860R doesn't have a compressor side boost reference fitting. I also need to get more looming for the flex fuel sensor wiring (in pink). I absolutely hate running additional wires into the car so I try and resuse neglected connections on the factory harness as much as possible. The flex fuel sensor is ran through the old narrow band O2 sensor's connector as it had 12v, GND, and two signal wires free! Purchased the mating connector and pinned it in through the ECUMaster adapter to the new ECU. I've done this other places as well for signals.

The IAT runs through the old MAF connector with a mating connector I found. I also recently ran the intercooler relay control wire through the old MAF connector as well. The only "new" wires I had to run into the passenger compartment were for the DBW throttle and wideband.

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The car seeing sunlight for the first time in well over a year.

I still need to finish up the air intake, final bits for that arriving today.

Some eagle eye'd viewers might of noticed the fuel pressure sensor isn't hooked up yet, thats because I'll be hooking it up to a different module!

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Purchased an ECUMaster ADU7 and a custom printed IPC replacement bezel from Mako Motorsports in Aus. I'll be running additional sensor wiring to the ADU through the soon to be available holes in the firewall from the throttle cable(s) and speedometer cable. I'll be running GPS speed with the dash and potentially converting to an electronic speed sensor from later year MR2s and ST205. Planning lots of cool little things with the dash to make it a seamless install. For now though, just focusing on getting the car in driving form again.
 

grip-addict

Active member
that looks really excellent. Especially the gtx2860. I'm looking forward to what results you have on it, since I'm running that same turbo but with a different turbine housing on my gen 3 motor.

If you have redesigned that DBW pedal adapter, is there any chance you'd be willing to ship one to me or send me the file? I'd happily send some beer money your way.
 

hoys

Member
grip-addict":1k00gjsx said:
that looks really excellent. Especially the gtx2860. I'm looking forward to what results you have on it, since I'm running that same turbo but with a different turbine housing on my gen 3 motor.

If you have redesigned that DBW pedal adapter, is there any chance you'd be willing to ship one to me or send me the file? I'd happily send some beer money your way.

I'll certainly provide the STL and part numbers once I feel it out a bit more. I've only putted around a few miles so far and might want to tweak it a bit.
 
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