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Discussion Starter #1
ok, i was told that in the true twin conversion that.

1) it is not as hard on your first turbo.
2) if you have a vacuum line leak, it will go away by doing this.

My question is I think my first turbo died for over boosting so, if i fo the TTC setup will is still be able to run 1.7-8 bar like i am now with out hurting on of the turbos?
 

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If I'm right it isn't as hard on your second turbo. Some people have posted it cured some of their boost problems. If the turbo will still push, it run it. TTC just changes the response and power curve a bit.
 

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It is not as hard on your 2 turbo because it elimanates the chance of compressor surge if the sequential operationis fubar
has nothing to do with a boost leak if your leaking you will continue to leak deal with it.

TCC has an alternate boost curve a little less at low rpm with a more consistent response at mid rpm. when bpu you booost to 10 psi then the 2nd comes on and you surge to 18 + psi makes it harder to drive smoothly with TCC you get a steady ramp up of power with a little more lag as the exhaust has to spool two turbos( in sequentila turbo number one gives a little boost as it pre spools number 2
 

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Just got my car switched to TTC and my feelings r kinda neutral at this time.
Pros: 1)-Linear & smoother power delivery
2)-Safer on your #2 turbo (so i have heard)
Cons: 1)-Exhaust sounds a little bit louder
2)-Low torque under 3000-3300 RPM
So at this time i still prefer TTC over the Sequential mode but car feels more responsive in the later.However in TTC once the tach goes pass 3300 RPM,the car just takes off :D Gotta love this feelings.
Regards. Yasir
 
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Question: wouldnt this be worse on tubo#1 because wouldnt it be overspooling???
 

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Info on Auto

How does this mod works on AUTO. Anyone have an idea....Specially one without EBC all others BPU in place.....

Also I have some concerns about becomming full BPU, meaning adding EBC and how it will treat my turbos and my trainny. Is there a lot of power increse by adding EBC...How much should I expect and what should I worried about?

Sorry is there s a lot to learn jeje
 

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Here are some more questions on the TTC Has anyone ever done the ETTC mod instead of the normal TTC? If so where is it better to do the mod from the ECU harness or the other way? Any advice would be much appreciated. THANKS
 

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well,
i have an '98 auto,27k miles and one week after i done true
twin turbo #1 went,i changed nothing else and this car is
maintained very well and driven by an adult.

just my story

randy
 
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Did you say you were boosting 1.7- 1.8 bar?? Are you on the stock turbos? If so, I think that's way too high. The most reliable boost I've seen a lot of people say doesn't hurt your turbos is around 18psi. I think you can push it to 22 or so to race, but I don't think running it at 1.8bar (~25psi??) is very healthy for stock turbos, no wonder your #1 turbo died. Maybe I'm missing something here, but no one else seems to have been bothered by that comment. . . strange. Stock turbos, right?

-Z.
 

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maybe he runs race gas all the time?

hwen i had my vsv mod.. i used to hit between 1.5-1.8 bar all the time.. mainly its the timing retard that sucks.



here is an intersting story.

i was on my way to MVP and one of my boost hoses popped off(did not know it at the time) and i hit 1.95 bar!!! im happy my turbos are still working lol.


needless to say my car felt like shit afterwards, cause of the timing retard and the plugs were fouled.

feels lots beter now that i change the plugs and reset the ecu!
 

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why do you think number 1 would overspool? all TTC does is look the IACV and EGCV open number one is still seeing the same pressure it would otherwise. TTC has been around a long time in the supra world and has not been shown to cause any additional long term problems other than that the stocker do not have as long a longevity with overboosting

here is a post from Andi Barachi from MKiv.com mailing list

If you're not BPU I wouldn't recommend TTC.

The reason we (well, some of us) do TTC is because of the very nonlinear, spikey
powerband that BPU causes in sequential. That is, when you've got 10psi from
turbo #1 and then all of a sudden your boost goes to 18psi in half a second when
the computer feels like it. That's not predictable, it's not smooth, and it's
very hard to drive it like that when you're cornering at the limits of
adhesion. Thus we go TTC which gives us earlier spool of the #2 turbo, but more
importantly, one smooth predictable ramp-up of power rather than sequential's
unpredictable kick in the pants. (Since sequential doesn't "ramp up" the boost
smoothly, it just hits hard).

Remember that Toyota's original design for sequential as NOT to have the boost
hit hard on the #2 turbo for more power. They designed sequential to spool the
#1 turbo early for good low-end torque, and then when the motor is turning
enough RPM's that one turbo alone cannont keep up with it, the #2 turbo is
activated simply to continue this broad smooth torque curve.. Boost goes up
slightly on the 1-2 transition (on the order of 2-3psi) but it's nothing major
like the BPU spike from 11 to 18psi..

Here are some stock Supra dynos....
http://www.gqma.d2g.com:81/kys/my_supra.html

Even in sequential I'd think these torque curves are quite driveable and
wouldn't TTC them. TTC is for BPU when you need a predictable, stock-like
powerband.

Regards,
Andi
 

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anothr post on the subject from Andi


Here is my old TTC vs. Sequential dyno:

http://www.boostaholic.com/tmp/ttc_seq_dyno.gif

As you can see, Sequential does spool up like you said at 2500, and between 2500
and 3500 sequential is beating TTC. At 3500 they're even, and between 3500 and
4300ish TTC kick's sequential's ass hard. At 4300 sequential spools the 2nd
turbo and it catches up to TTC, and for all intensive purposes TTC and
sqeuential are the same once sequential has activated the #2 turbo.

The reason this chart made more hp overall in TTC is because TTC let me get
20psi on the dyno, and Sequential was only letting me get 18-19ish.

Andi

 

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Discussion Starter #16
Yea I said 1.6-1.8 bar.

See this is what happend, wife came home and said your car sucks. I say why she said it will not go. Im like ok it went fine last night.......get the keys go for a ride, Hum..... She is correct for once, first turbo not somming on. It spools but no boost. look for the usual, and say well hell try this, un hook the actuators. still noting on the #1, #2 come on and makes, 1.3-5 with a hiss hisss hiisss sound. AH......... Sound like a boost leak no problem. Hook the actuators back up and drive again. same thing, so i say fkit, its under warranty take it to the toyota dealer and they keep it 3 day. say we cant find the problems cause you have a down pipe, and BCC. :( I told them that would have noting todo with #1 now comming on in any gear. Make a long story short she said take the parts so we can get the computer info off it. We think you turbo needs to be replaced.

So i guess the #1 has died over night. No clues or anything, it just killed over dead. we are talking no smoke, no wine, nothing. made 1.4 bar one night went home went to bed and it had a heartattack i guess?
 
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KERR said:
Yea I said 1.6-1.8 bar.

See this is what happend, wife came home and said your car sucks. I say why she said it will not go. Im like ok it went fine last night.......get the keys go for a ride, Hum..... She is correct for once, first turbo not somming on. It spools but no boost. look for the usual, and say well hell try this, un hook the actuators. still noting on the #1, #2 come on and makes, 1.3-5 with a hiss hisss hiisss sound. AH......... Sound like a boost leak no problem. Hook the actuators back up and drive again. same thing, so i say fkit, its under warranty take it to the toyota dealer and they keep it 3 day. say we cant find the problems cause you have a down pipe, and BCC. :( I told them that would have noting todo with #1 now comming on in any gear. Make a long story short she said take the parts so we can get the computer info off it. We think you turbo needs to be replaced.

So i guess the #1 has died over night. No clues or anything, it just killed over dead. we are talking no smoke, no wine, nothing. made 1.4 bar one night went home went to bed and it had a heartattack i guess?
At 1.6 bar, you're probably pushing detonation with pump gas. It's bad for your engine. Don't go much over 1.3 bar with stock turbos if you want longevity.

As a rule, Toyota dealers don't know &#*$^* about our cars and will do anything to wriggle out of warranties. If you're gonna modify your Supra, learn to work on it.

Hooking the actuators up will NOT solve a boost leak. You probably have a leak at an IC hose. Pressurize your intake to find the leak. If you had a bad turbo in TTC you'd probably hear a wooo sound and see little or no boost (as in, 0 bar, not 1.4 bar).
 

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at 1.6 t0 1.8 bar(23- 26 psi ) it is no wonder you fried your turbo. either go single or if you want them to last keep it to ~18 psi. the stockers are not made for that boost level for long. I hope your warranty is going to cover the turbo They might but If Iwere them I would look at the aftermarket stufff and say un unh
 

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Discussion Starter #19
i dont see why they will not cover it, I dont have a boost controler, besides when they drive it is always makes .9 bar 13 psi.

Also im not upset that one has died. The car has 42K miles on it. so eithor way its toyotas bill, im under the 5 year 60 power and the 7 year 100K mile extended, Also they have done all the service for the last 3 years, and they issued the extended warranty with those parts on the car.
 
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