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I am debating wether or not to do TTC/ETTC before tonight because I wanna do a little racing, and I have an AUTOMATIC which is BPU and has clipped/polished turbos... just basic BPU though.. DP, RM, BCC, Intake...

Will TTC make my car faster in acceleration and yield better quarter mile times, or just make the power delivery smoother with no #2 kickstart?... any more horsepower at all possible?

I know lag is an issue, and more so on an AUTO like mine... but I am BPU so I was wondering if any AUTO guys have done this... otherwise your input will still help me if you have a 6speed.. Sooner the better I plan on going out in 2-3 hours... but its ok if I do it tommorrow I guess...

:D
 
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I run eTTC on my 94 BPU+ (FMIC) AUTO.

When I'm on the street, or just being a lemming (heavy traffic) I usually keep it in Seq so the lag is small.

When I am on the freeway or in a race (at high rpms) I switch to TTC so that I don't have the transition lag (1 spools down so 2 can spool up), and I get faster boost response.

If you have the time, do the eTTC and you can see for yourself.
 
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The E-TTC mod is pretty good for highway racing, but doesn't it have pretty detrimental effects on the engine? Correct me if I'm wrong, but several people have had bad experiences with them...

I've been advised to stay away from it by several Supra owners...
 

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achilles99 said:
The E-TTC mod is pretty good for highway racing, but doesn't it have pretty detrimental effects on the engine? Correct me if I'm wrong, but several people have had bad experiences with them...

I've been advised to stay away from it by several Supra owners...
Sorry,

But that is the problem about "rumors" going around that is totally untrue. I am the creator of the eTTC mod. I have ran it for over 1-1/2 years now, R&Ding, testing and improving it (30,000miles later), so my "facts" right now will override all the "opinions" you have heard.

Let me start off by explaining the Supra's Sequential System to you in Simple Terms:

When your car is making about ~8psi boost on turbo #1 (BPU Level), at about ~3500rpm, the ECU will send a signal to the EBV (Exhaust Bypass Valve) VSV (Vacuum Switching Valve) to open it's EBV actuator. This does two things: 1) act as a wastegate to keep boost levels of turbo #1 at a constant (~10psi), and 2) "bypass" (thus the name "EBV") some of that excess #1 pressure into the #2 turbo to slightly spin it. By now, your boost should have dropped a bit (boost transition lag), and your #2 should been "prespooled". At 4500, the ECU then sends 2 more signals, to the EGCV (Exhaust Gas Control Valve) and the IACV (Intake Air Control Valve) VSV's. The EGCV's airflow will join in w/ the EBV's to give you a smooth transaction with a "kickstart." The operation of the EGCV is then followed IMMEDIATELY by the opening of the IACV, which then brings the #2 turbo fully online. The IACV and EGCV VSV's are simple electronically-activated (12v) vacuum switches that open and close when a voltage is applied. The pressure is supplied by the nipple of the #1, which gets directed by the VSV's. When you let off the throttle, the ECU then gives these VSV's a "halt" by cutting off the signal. This will then direct all the pressure originally in the actuators out into the atmosphere, thus disabling the #2 turbo.

So what the eTTC mod pretty much does, is keep the two IACV and EGCV VSV's "activated" at all times, which will keep the #2 turbo online at all times by supplying them with an outside power source. The sequential system relies heavily on the Pressure Tank on the car (a simple $50 plastic bottle that stores air), and eTTC mod relies heavily on the pressure tank. A lot of people who have experienced problems w/ the eTTC mod has a bad pressure tank, which through time wears out and leaks, and is not caused by the mod itself.

The eTTC mod is totally safe, and can be performed with a simple DPDT rocket switch and simple wiring...assuming that you have some background in electical wiring. Some people have screwed up their cars because they have absolutely NO idea on what they are doing, such as cutting their ABS wire. :wtf:

The eTTC mod can be found here.

Please feel free to contact me if you have any questions.

-Jeff
 
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GREAT answer... the best one I've seen yet. I guess you DID invent it :)

Anyhow, sorry to offend. I was just trying to get the people who had problems with it give a reason why.

I went through this same "rumor" mill about the HKS EVCIII unit that I had. A lot of people complained that the fuzzy logic was the culprit. After calling HKS, they sent me the supplemental instruction manual that was written for Supras. Turns out that they were almost completely reversed from the general instructions! The boost controller works perfectly now...

Thanks for the clarification, Jeff. I might contact you directly to ask a few more questions about the E-TTC mod before starting any vicious rumors on the forums ;)
 
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