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After replacing my leaking ECU capacitors, I'm not convinced my ECU is 100% fixed. Extremely frustrating! If there was an economically Plug-n-Play, aftermarket ECU with OEM+ functionality (boost/timing control, engine monitoring, traction control, auto transmission management, etc.), without spending thousands+++ on bespoke tuning and sensors, I'd be all over it.

OEMs do not individually dyno tune each mass-produced vehicle... it would be nice to have a modern plug-n-play aftermarket ECU option that replicates the stock engine parameters without additional dyno tuning.
Have you tried this guy here with refurbishing your ECU?
He was recommended by a former SFS employee.
 

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I have owned my MKIV for almost 23 years now. Went BPU a few days after I bought it. Bumped it up to around 450 RWHP over time and it was always a blast. Never once thought of selling it or replacing it with something modern. But then the wastegate went (stuck open) and so I am going to get Stu's GT-28s now.

Not going to go full out instantly. Maybe 450-480 RWHP again at first, then buy a standalone ECU, injectors and fuel pump in a few years. Also first gotta find someone who would tune the standalone ECU properly, so it feels GT-like, like BPU/stock.

I just love the GT feeling of a BPU Supra. Just cruising around relaxed and comfortable, and then floor it when you feel like it, bringing a big grin into my face still.

I tried TTC for a while but I never liked the lack of low-end power, so I am staying sequential, even if that means more potential problems over time. I will for sure replace all vacuum lines and VSVs when I replace the turbos, so that should prevent a lot issues in the hopefully many more years to come.

So far I never had serious issues except the wastegate issue now and multiple broken EGCV flaps over time (I guess thats simply unavoidable with so much boost/heat on the stock twins at BPU levels). That reliability was a huge reason why I bought it in the first place.

The only issue I have is finding a clutch thats quiet enough (keeping the stock flywheel) and can hold (later) ~600rwhp without causing crankwalk. I still havent found one.
i am in the same boat except my second turbo went. Would you attempt to keep the wastegate closed with spring mod or is it broken.

if your are on your way to gt28 and still looking for that bpu responsive sequential, I would recommend to keep your stock cams. My hks264 cams, custom exhaust manifold made the boost kick in around 3k rpm rather than 2k. It kind of defeats the sequential purpose unless you can delay transition to 43-4500 rpm and like the idea of maintaining higher RPM pull. (Which was my reason for having it in)

I’m currently working on getting my sequential in tip top shape and maybe looking to mod the transition point while still retaining stock ecu
 
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I still have the stock twins in my car and did loads of things other then going single. I have had the car for 22yrs now and don't regret it at all. Out of all the supra guys locally my car has been down the least of everyone, except that one time I was waiting on wheels from japan and prematurely sold the wheels off my car. Mechanically speaking my car was simple and reliable. My perspective and philosophy when I worked on my supra was to build something well rounded and focus more on the response and handling. When it came to the subject of the turbos honestly speaking it was a budget thing that kept me from going single but I also felt it was a shame to replace perfectly fine working turbos. I was determined to keep the stock twins until they blew before I'd go single and they are still going strong. I don't drive the car regularly as much anymore but that's more due to personal annoyances and convenience issues I have, not the car itself.
Are you me? Good to see a kindred Supra spirit. Ive had my car for ~10 years now and am mildly BPU, focusing on driving the car and modding for drivability/livability. I'll get to the twins when they go, but from 35k-85k miles in 10 years they show no signs of blowing any time soon.
 

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i am in the same boat except my second turbo went. Would you attempt to keep the wastegate closed with spring mod or is it broken.

if your are on your way to gt28 and still looking for that bpu responsive sequential, I would recommend to keep your stock cams. My hks264 cams, custom exhaust manifold made the boost kick in around 3k rpm rather than 2k. It kind of defeats the sequential purpose unless you can delay transition to 43-4500 rpm and like the idea of maintaining higher RPM pull. (Which was my reason for having it in)

I’m currently working on getting my sequential in tip top shape and maybe looking to mod the transition point while still retaining stock ecu
I used the spring mod for years. Now its stuck for good. Not going back or forth. Seems to be only a tiny bit stuck open, because I still get about 14.5 psi boost.

Thanks for the advice. I am trying to keep as much stock as possible.
I was planning to get Stu's new manifold, though. Is that the one you have? Youre saying they delay spooling of #2?
 

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I used the spring mod for years. Now its stuck for good. Not going back or forth. Seems to be only a tiny bit stuck open, because I still get about 14.5 psi boost.

Thanks for the advice. I am trying to keep as much stock as possible.
I was planning to get Stu's new manifold, though. Is that the one you have? Youre saying they delay spooling of #2?
I think hks264 definitely does, and running anything bigger than stock turbos will have some inherent turbo lag. I have custom exhaust manifold from Stu and it’s increased internal volume should also give it some delay. How much is each individually going to contribute? I can’t say.

If you are debating between stock manifold and custom for pure responsiveness, I think stock will be best. If you want to future proof and not go and do it again when you push the limits of the gt28 then do it.Stu put 10 years of heart and soul into the manifold and I doubt anything like this will be available in the future.
You really want to chase stock but with gt28r and not afraid to go into it multiple times then stock manifold, port manifold, stu manifold and play with it all you want. Haha. Lastly, beware of coolant leaks with the gt28r set up as the coolant hose design for it is not ideal. My mechanic did go braided with AN fittings but only time will tell if it holds up
 
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@Disguised - I contacted that person. Not interested in giving that person my business.
 

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I still have the stock twins (in excellent shape, took them off at 42K miles and currently at 45K with the single) and all the BPU upgrades in storage - only thing from BPU still on the car is the HKS Carbon Ti. BPU was fun zipping around town at ~16psi and those twins screamed, but I wanted more.

I don't know who else has BC 264 cams, but with a custom 4'' DP and 4'' midpipe with a recirculated gate, I do not see any torque difference from BPU, in fact, it may be a little more. Single scroll, cast log manifold. Opening the exhaust too much (tubular, straight pipe etc.) is good if you have high power goals or run it at the track for numbers/dyno, but for my purposes, I wanted that torque to stay (weekend cruiser, spirited runs every time I drive, fair weather only, no racing etc.). To be honest, even off boost, the car's torque is damn near the same way it was when I was BPU. The cams aren't too aggressive and provide a decent lope too. BPU was very fun but single turbo is just intoxicating - that sledgehammer hit getting into full boost can't be beat.

AEM V2 here and I absolutely love it, plug-n-play.

My .02
 
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I still have the stock twins (in excellent shape, took them off at 42K miles and currently at 45K with the single) and all the BPU upgrades in storage - only thing from BPU still on the car is the HKS Carbon Ti. BPU was fun zipping around town at ~16psi and those twins screamed, but I wanted more.

I don't know who else has BC 264 cams, but with a custom 4'' DP and 4'' midpipe with a recirculated gate, I do not see any torque difference from BPU, in fact, it may be a little more. Single scroll, cast log manifold. Opening the exhaust too much (tubular, straight pipe etc.) is good if you have high power goals or run it at the track for numbers/dyno, but for my purposes, I wanted that torque to stay (weekend cruiser, spirited runs every time I drive, fair weather only, no racing etc.). To be honest, even off boost, the car's torque is damn near the same way it was when I was BPU. The cams aren't too aggressive and provide a decent lope too. BPU was very fun but single turbo is just intoxicating - that sledgehammer hit getting into full boost can't be beat.

AEM V2 here and I absolutely love it, plug-n-play.

My .02
did you have your stock twins with cams already or were you able to see what stock twins in sequential and stock cams feel like.
 

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IMO All MKIV Supra's need to roll around on the street with +800hp just to let these newer cars know who's boss but when come time to sell a stock motor needs to go back in and the built motor/ parts sold separately. That way you enjoy these cars the way they should be and still able to fetch the most ROI.
 

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It seems most APU owners have had direct stock twins/BPU experience, but the converse, at least in this thread, is not, necessarily, true. Some opinions offered reflect this, which is not a bad thing.

I rarely, if ever, give rides but, when I have, I've always taken the time to show how user-friendly an APU car can be, making a point to trundle around town and to deliberately drive in the dreaded SoCali bumper to bumper. Then, I've taken the opportunity to "clear their sinuses" to show why the MKIV Supra earned its reputation as God's Chariot.

The first time I recall doing this was when I gave a ride to the author (@mvaughn) of an AutoWeek magazine article on Blackie as part of his research on the article. I didn't understand, for a moment, why he was very noticeably tense until he told me all the big power cars he had been in were big block domestics that were not particularly tractable.

Driving around my home town, before getting on the freeway, utterly amazed him, even more so when the legendary power of the 2JZ-GTE kicked in. So the moral of this story, my Supra brothers, is, if you're a stock twins/BPU guy, drive an APU car for a month and, if you're an APU guy, drive a stock twins/BPU car for 30 days. I'm pretty sure you will enjoy the experience immensely because the only thing better than one Supra is two Supras. 👍👏💪👊😎

P.S. The session with AutoWeek happened many years ago. Since then, advances in engine management systems and turbo technology, in particular, have improved APU cars even more.


Ken.
I was one of the lucky ones because your APU Supra was the first Supra of many I had a chance to ride in. I was 14 or 15 years old at the time when I asked him for a ride one day. Had to be 1997-1998ish. I remember it vividly like it was yesterday. You had just got your car done for SILV and it was at LVMS. SILV was the only big meet at the time. People came from all over the country and it was exciting. I lived in Lost Wages at the time(Las Vegas) and didn't have to travel anywhere.There were huge crowds. Most of the cars were super clean unlike today when you see hoopty Supras driven by people who shouldn't own a Supra. I got to the LVMS drag racing part of the meet and the huge parking lot had another event going on so there were cars of all types everywhere. I had to hunt down the section where the Supras parked because I knew they would all park together. I found it. Mani J, Guilly P, Ryan W, Mark, Saad Saad, and Powerhouse Racing car, Dana W, and Ken H cars were lined up behind the stands in a Supra row. Went straight over to Blackie. The paint on the Do Luck kit was so deep smooth and flawless, deep dish on the Work wheels were like mirrors reflecting the thin spokes. Brembo F50 red calipers stunting a challenge of speed. Not a speck of dust found on the car inside or out. New Sparco Milanos smelled new and leathery. I remember the carpet being immaculate like no one ever put a shoe on it. I didn't want to set my feet down on it. It was that clean. Went to watch from the stands the races that ensued. Close to the end of the races we all got up to head out. I was talking with Ken that time about some invention I made of a Lag-less Turbo as we walked back to the car. He offered to take me for a quick ride.

Ken fired up the car. Loud clutch rattle and a deep guttural rumble you can feel in your chest that doesn't come across in videos. Had a slight lope, so it definitely had cams. Lights come on and a familiar Toyota green glow is on the gauges contrasting the white and red Defi gauges in a four pod cluster on the side of the dash. People were crowding around the car scooching by to get a closer look. Ken pulls the extended pole that was holding up the hood set the hood down gently and pressed the hood firmly with a microfiber cloth in your hand. Click and click latching positively each side. My heart beats faster. A Ninja smile stealthily creeps on my face without my consent or knowledge ear to ear. "I'm about to ride in a 800hp Supra!" I am excited. Ken gets in and closes the door. He backs up and turns to towards the racetrack off the LVMS parking lot. Adrenalin is kicking in full blast as I knew what these cars were capable of and we are doing 5mph.

Ken leans over and says to me, "You hear that?" Engulfed in the senses of smell of fuel and burnt rubber from the drag strip and all the senses of riding in the Supra I snap back to the present and focus on the engine noise. "What kind of noise are you talking about?" I say after performing a complete cross checked aural spectrum analysis the walboro fuel pump noises, built and cammed engine and Greddy TD06 turbos whirring away and a Titanium Veilside Extreme exhaust sounding like heaven. Ken says "In the middle of the engine right here I can hear a fuel injector noise or something can you hear it?" I was naive and engrossed in listening for the noise to realize what sneaky sneaky Ken was up to. The car had driven out of the parking lot by then. We were on a strech of racetrack that had no cars on it. He was rolling about 5 mph when I leaned forward to hear the noise better and Kenneth J Henderson Popped in the clutch revved the engine past 4k and dropped the clutch right as I am leaning forward. BraaaaaaaaaAAAAAAAAAAA routed in wastegate opens and 295 section width Bridgestone Pole Position S01's are scrambling for traction rear end waggling turbos spooled in peak boost the car slingshots forward with an alarming urgency.

I get slammed in the seat hard. I didn't know it was possible to pull enough acceleration G's to make a smile connect in the back of my head. But the Supra pulls enough G's to do it. Being thrust into the deep padding of Milano seat my feet came off the floor and went back toward the seat as the car shot from first gear; pops the clutch and pulls the veilside shift knob into second and then almost immediately pops the clutch and pushes it again before you proccess what is happening O-MCFREAKING-MCFLIPPIN @#$%$%^ @#$%#@$%@, $%&^%^& Third gear starkly startled me because up till that point all the fast-ish cars I rode in before that got slower after first and second. This car got three times faster in third than the first and second. The car went from 5mph to ~110mph in what seemed like 4 seconds. Brembo F50 brakes slowed the car down just as fast as it got up to speed. I must have looked at Ken like he shot a baby because he smiled looked at me and asked, "Are you OK? Arrre you surrre? Do you want to go ag.." "YESSSSSS GOOOOOO AGAINNNNNNN!!!!" I cut him off before he can finish his sentence. Rascal tricked me about a noise. I didn't care. He turns the car around and I just focused on soaking in the experience as fast and as much as possible. braaaaaaaaaaaAAAAAAAAAAA First gear, second gear and I think I yelled out "money!" as he hit third gear for reasons unbeknownst to the human race. Whoooooooo! WOW! this thing PULLS. Jeezits Crackers what is Fourth gear like? Fifth? Sixth? I want to know NOW! AGAAAAIN! As we creep back through the parking lot I'm taking in all the senses. The car had no rattling other than the clutch, no creaks, there was a "Supra smell" that all Supras have that is distinctive and I have only experienced in a Supra. I will forever remember my first Supra ride in Blackie here we are 25 years later. Ken is a class act so, I forgive you for pulling a quick one on me with that, "whats that noise" thing. :cool:
 

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did you have your stock twins with cams already or were you able to see what stock twins in sequential and stock cams feel like.
As BPU, I had Stock twins (on stock sequential), and stock cams. I would think any worthwhile cam (even less than the typical 264s people go with) with the stock twins would be kinda pointless because the flow just isn’t there.
 

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The only issue I have is finding a clutch thats quiet enough (keeping the stock flywheel) and can hold (later) ~600rwhp without causing crankwalk. I still havent found one.
I only have about 2k miles on my single conversion but running a southbend stg 3 endurance. Stock factory feel and engagement, and holds the power perfectly without issues. It’s quiet, I don’t think I hear it at all. Stock flywheel reused .

FWIW, I’m about 700rw & 29psi through a BWS364,5sxe. Spools around 3700, fully in by 4,3ish and holds boost all the way to 7ish-7,2. Clutch holds torque and power perfectly through the gears, I absolutely love this clutch but heard they’re hard to come by nowadays and limited inventory. It drives , to me anyway, just like a factory Supra and that’s exactly what I wanted.

Honesltly, I’ve owned a lot of powerful street cars. From the turbo vette to upgraded blower E55 to a single turbo M3 etc. and if I’m being very frank, for me, anything over this power level (650-700rw) simply starts taking away the fun of it for me because my cars are all street cars. With traffic, congestion, lights, potholes, crappy freeways etc., the power is hard enough to use as it is, I can’t imagine another 300hp for instance. It would take a lot away from me for the car and what I want, I’m not chasing numbers or personal bests anymore.

my .02
 

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i installed some JUN 264 cams about a year ago and it made a huge difference. lost some power on the low end but what i gained on the top more than made up for it. should have done this years ago.
 

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After replacing my leaking ECU capacitors, I'm not convinced my ECU is 100% fixed. Extremely frustrating! If there was an economically Plug-n-Play, aftermarket ECU with OEM+ functionality (boost/timing control, engine monitoring, traction control, auto transmission management, etc.), without spending thousands+++ on bespoke tuning and sensors, I'd be all over it.

OEMs do not individually dyno tune each mass-produced vehicle... it would be nice to have a modern plug-n-play aftermarket ECU option that replicates the stock engine parameters without additional dyno tuning.

while I’m not well versed in these but it’s one of the plugn play options and this guy seems to have figured out the sequential set up.
 

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Very interest thread. I have a fairly virgin ‘94 Supra that I’ve avoided modifying. This is against my inner self, that has modified vehicle I’ve ever owned, but I’ve managed to not sink my claws into it. Right now, it only has exaust- downpipe, cat, and a Greddy EVO cat back. I have the stock exhaust mothballed. I’d like to do more BPU things, but I want it to look as stock as possible and be completely reversible. I did collect some parts - I have a Greddy fuel cut box, boost controller, patch harness- but never installed them.
 
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