Just did the TTC and then changed it right back!

Just my thoughts on TTC. (Auto)The car felt very sluggish and to top it I was beaten at the light by a saxo VTR up to 35mph40mph. The boost starts to build about 3rpm and full boost by 4rpm. I really did not see the point of this mod. Changed it right back then thank god the car moved again like it should. The only two advantages are that the power build up is predictable and it sounded like a beast. Probably better on a manual !

ya exactly. I really dont think its meant for Auto's. Even so I clocked better 0-60 times in sequential mode as opposed to TTC in my manual.

on the dyno you gain a little torque also if your doing motor way runs you save a fortune in fuel i think class one was getting 100 miles more on motorway runs other than that pointless

what is really the difference having ttc mod?

how does this effect the fuelling of the car...meaning the ECU AFRs map...

How can you gain torque?

Where exactly is this extra "torque" coming from?

Most probably it was within the margin of error of the dyno measurements, especially if the engine temp was not identical during both runs.

In both configurations max torque comes when both turbos are singing in parallel, so it won't be any different.

John, how would the tcc mod affect fueling? if anything, i figured it would suck harder

After you've just done it, the fuelling and ignition would be substandard, because the ECU would still think it's in sequential. So that won't be a fair comparison.

After the ECU has been reset and has learned a thing or two, it will be closer to the mark.

The sound is louder at lower revs, of course it is, because the first turbo is not making boost so it doesn't act as a silencer (as it does in sequential mode)

For the same exact reason fuel consumption below 4Krpm will be a bit lower, because lower boost would need less fuel to pair it with.

The sound is louder at lower revs, of course it is, because the first turbo is not making boost so it doesn't act as a silencer (as it does in sequential mode)

so on idle its louder cause its not on boost ?

what about when in sequential on idle its not loud then and not on boost ?

number 1 and number 2 are both silencers if you look at it that way the reason it is louder is the exhuast vsv is now open so 2 ports are open on the down pipe not just the one ?

After you've just done it, the fuelling and ignition would be substandard, because the ECU would still think it's in sequential. So that won't be a fair comparison.

After the ECU has been reset and has learned a thing or two, it will be closer to the mark.

 

The sound is louder at lower revs, of course it is, because the first turbo is not making boost so it doesn't act as a silencer (as it does in sequential mode)

 

For the same exact reason fuel consumption below 4Krpm will be a bit lower, because lower boost would need less fuel to pair it with.

...so on idle its louder cause its not on boost ?

close.

On idle it's louder because there is far less restriction for the exh gases. They EGCV is wide open on TTC, remember.

what about when in sequential on idle its not loud then and not on boost ?

I don't understand this question, sorry.

I have a thorough explanation of the workings of the supra sequential if you're in the mood for deeper reading

close.

On idle it's louder because there is far less restriction for the exh gases. They EGCV is wide open on TTC, remember.

 

I don't understand this question, sorry.

 

I have a thorough explanation of the workings of the supra sequential if you're in the mood for deeper reading

i think we are a little mixed up here we just said the same thing ?

Im currently in TTC, mines a manual TT, and i have noticed a big gain in mileage per full tank im getting atleat 60miles more, this isnt a fluke or different driving habbit, just makes sense to me, at motorway speed turbos are not runnigs, even when crusing in street im always below 4000rpm, yeah its slugish but im saving alot of fuel, but once im at WOT im always above 4000rpm and stay above it, it feels more torquey to. am i might be imagining all this?....erm nope!

Im currently in TTC, mines a manual TT, and i have noticed a big gain in mileage per full tank im getting atleat 60miles more, this isnt a fluke or different driving habbit, just makes sense to me, at motorway speed turbos are not runnigs, even when crusing in street im always below 4000rpm, yeah its slugish but im saving alot of fuel, but once im at WOT im always above 4000rpm and stay above it, it feels more torquey to. am i might be imagining all this?....erm nope!

mate your right both turbos working boosting up together will produce more torque also if you stay below 4000 rpm you will not be using boost so you will save money on fuel as well

i have seen all this on the dyno so many times.

i think we are a little mixed up here we just said the same thing ?

Probably, I just didn't understand the last part of that post, as I said:D

Below 4Krpm with TTC you get less airflow, so less fuel is needed to run closed-loop. Hence the better mpg.

Over 4Krpm both turbos are running in parallel just like they do in sequential mode --- so you get no extra power (or torque, it's the same thing)

The feeling of power is more pronounced in TTC however, because all the torque comes at once. In sequential mode a lot of the torque is already there since 2000rpm or so, therefore the 'step' is not as pronounced.

Im currently in TTC, mines a manual TT, and i have noticed a big gain in mileage per full tank im getting atleat 60miles more, this isnt a fluke or different driving habbit, just makes sense to me, at motorway speed turbos are not runnigs, even when crusing in street im always below 4000rpm, yeah its slugish but im saving alot of fuel, but once im at WOT im always above 4000rpm and stay above it, it feels more torquey to. am i might be imagining all this?....erm nope!

In sequential the turbos don't run at 80mph either/ only if you put your foot down a little harder then normal acceleration. So the only way it saves on fuel in TTC is that your car just does not boost below 3 even when you plant it. So that’s why your fuel economy has gone up. Surely just have sequential and drive with light acceleration and you will achieve the same fuel economy as you won’t boost. Except with the sequential setup you also have the power down low when you need it.

In sequential the turbos don't run at 80mph either/ only if you put your foot down a little harder then normal acceleration. So the only way it saves on fuel in TTC is that your car just does not boost below 3 even when you plant it. So that’s why your fuel economy has gone up. Surely just have sequential and drive with light acceleration and you will achieve the same fuel economy as you won’t boost. Except with the sequential setup you also have the power down low when you need it.

That makes sense to me, for normal driving, of course you will save fuel if you have no low down boost, at the cost of no low down grunt either and that's one thing I love about the supe, in any gear at any rpm it pulls like a train (in sequential mode). It's like no other turbo car I've driven, coupled with those j-spec turbos you have on tap responsiveness as if you were driving a 6l N/A engine lol

Interesting thread though, I was thinking of trying out TTC mode too, don't think I'll bother now since I love the sequential set up and so this sounds like a complete let down.

You can actually go the opposite way (compared to TTC) and increase low-down boost by fitting an MBC on the first turbo.

It's a bit fiddly, but well worth it.

That's playing the supraTT at it's strengths and not trying to make it something it isn't.

interesting John, I get about .8 bar on #1 turbo, could that be increased much? Have you tried it out?

a bit of a hijack but will the SBCID work in auto mode properly when in TTC mode?

i ask this because i always thought the sequential thing confused the controller so if in TTC mode it should work right?

and has anyone tried it?

interesting John, I get about .8 bar on #1 turbo, could that be increased much? Have you tried it out?

You can push it a lot over 1 bar, but at some point you start starving #2 from the required prespooling. When that happens you end up with a 'hole' in the power delivery around 4Krpm.

Do it right and it's all gains. There is quite a bit of exh gas volume that bypasses both turbos in the stock setup via the wastegate and the EGBV.

I thought that everything that could go through turbo #1 does go there, but apparently there is room for improvement. I've got the setup on my site. (I have not tried this on a JSpec so I can't vouch how well it's gonna work on them. Most likely it will be fine, but until you try something it's speculation)

interesting John, I get about .8 bar on #1 turbo, could that be increased much? Have you tried it out?

I get that with both online. (Stock) 0.6 on 1st and 0.8 on second. can't begin to imagine the gains when BPUed. Gonna happen soon!

I get that with both online. (Stock) 0.6 on 1st and 0.8 on second. can't begin to imagine the gains when BPUed. Gonna happen soon!

it becomes an interesting car at BPU

I wouldn't advocate just switching to TTC on a stock Supra, but if you have an emanage or similar to map the fueling/ignition then I would definitely recommend it.

I had mine switched to TTC 4 years ago by my tuners, with the emanage mapped acordingly. Yes you loose a little low down torque, but this is made up by gains mid rev range, which is where you want the power, unless you're into traffic light races

It is probably not suited to auto Supras, but with a manual it is so much better IMO, as you get a much smoother power curve with no dip in the middle as the 2nd turbo comes on line.

Here's the dyno from mine in TTC.

i have noticed a big gain in mileage per full tank im getting atleat 60miles more,

so how does that translate into MPG..?