NA-T questions

Im am desperate to get the Whifbitz NA-T kit fitted but have a few concerns. My engine only has around 60/70K on it and runs like a dream, uses no oil, no smoke etc, i dont want to bugger such a good engine. It will be the basic NA-T conversion running the quoted 0.5 bar boost. I dont want crazy power and will be happy with the 360-ish HP it reportedly produces.

How reliable is the car afterwards? I am concerned that engine life could be reduced. Is it really safe to turbo an NA engine without lowering the compression even if it is only running 0.5 bar?

Is it possible to have a switch of some kind fitted to allow less than 0.5 bar boost for everyday driving or is there really no need because the conversion is perfectly safe to always run 0.5 bar?

My car is also an auto. Is the box able to withstand the 0.5 boost ok with no reliability issues?

I value my car at around 9K as it is. The kit costs around 7K supply and fit. Approx how much value would it add?

So long as it's tuned correctly your engine will remain healthy, wouldn't overthink that. If you can be bothered you could always buy another 2JZGE engine for ~£500 and do your conversion to that and drop it in, I wouldn't though,

0.5 bar boost is barely anything you won't have any major reliability concerns other than the usual service items of a 2JZ. With a higher compression engine you only need to worry about fuel octane and potential detonation, but if you are using decent fuel Shell V power for example and keep the boost at 0.5bar you won't have any issues with this.

I can guarantee you that after a few months of driving you will be asking how to put a switch in to turn it up from 0.5 to higher, not a switch to do the opposite. 0.5 bar is already very low. In my opinion trying to have a wastegate spring lower than 0.5 is a waste of time.

The only problem you will have with this setup is the autobox. NA autobox does not like power, anything more than 300hp/300 ft.lbs of torque and you are asking for it to shit the bed. In particular, it does not like shifting gears with that much power running through it when you are wide open throttle. To make the box last longer you need to lift off the throttle in between gear changes.

Your best way around this is to either stick a manual box in it at some point, or go ask DavidP if he can hybrid your autobox which should let it hold around 550ft.lbs I think.

Car would probably be worth around 13-14k I would say.

Like always, brilliant advices from Mike

Preempting a list of wrong questions...........

What is a Hybrid transmission?

http://www.mkivsupra.net/vbb/group.php?discussionid=82&do=discuss

How do you get one?

http://www.mkivsupra.net/vbb/group.php?discussionid=90&do=discuss

If I learn of any components, I post them here.

http://www.mkivsupra.net/vbb/group.php?discussionid=86&do=discuss

Please note that the links don't work with Crapatalk.

So long as it's tuned correctly your engine will remain healthy, wouldn't overthink that. If you can be bothered you could always buy another 2JZGE engine for ~£500 and do your conversion to that and drop it in, I wouldn't though,

 

0.5 bar boost is barely anything you won't have any major reliability concerns other than the usual service items of a 2JZ. With a higher compression engine you only need to worry about fuel octane and potential detonation, but if you are using decent fuel Shell V power for example and keep the boost at 0.5bar you won't have any issues with this.

 

I can guarantee you that after a few months of driving you will be asking how to put a switch in to turn it up from 0.5 to higher, not a switch to do the opposite. 0.5 bar is already very low. In my opinion trying to have a wastegate spring lower than 0.5 is a waste of time.

 

The only problem you will have with this setup is the autobox. NA autobox does not like power, anything more than 300hp/300 ft.lbs of torque and you are asking for it to shit the bed. In particular, it does not like shifting gears with that much power running through it when you are wide open throttle. To make the box last longer you need to lift off the throttle in between gear changes.

 

Your best way around this is to either stick a manual box in it at some point, or go ask DavidP if he can hybrid your autobox which should let it hold around 550ft.lbs I think.

 

Car would probably be worth around 13-14k I would say.

Thanks for the in depth reply. Now i have a dilemma. It looks like going turbo with the original NA auto box is going to lead to problems even just running 0.5 bar. This leads me to wonder if it is not better just selling the NA and buying a turbo as with what my car is worth + turbo conversion, i could just buy a turbo without all the conversion hassle. The problem i have is that my NA is a really good car, never been welded and solid and its all there and pretty much all original and standard with only around 60-70K on the clock.

Am I using invisible ink?

http://www.mkivsupra.net/vbb/group.php?discussionid=143&do=discuss

A little offtopic. As I am far away from UK and wont be able to get a TT box. Maybe I can buy from David P already built auto box for NA-T applications?

Am I using invisible ink?

 

http://www.mkivsupra.net/vbb/group.php?discussionid=143&do=discuss

No but if i was to go to the trouble of messing with the auto box, i think id just do a manual conversion but thanks for your info, its another option. I really didnt want to start messing with the box. The Whibitz website makes it sound like the NA turbo kit is suitable for just bolting on to the auto and thats it. This is part of the reason i put this post up, to find out if it really is just as simple as fitting the turbo kit and ending up with a turbo Supra thats reliable.

Thanks for the in depth reply. Now i have a dilemma. It looks like going turbo with the original NA auto box is going to lead to problems even just running 0.5 bar. This leads me to wonder if it is not better just selling the NA and buying a turbo as with what my car is worth + turbo conversion, i could just buy a turbo without all the conversion hassle. The problem i have is that my NA is a really good car, never been welded and solid and its all there and pretty much all original and standard with only around 60-70K on the clock.

Mine started as an NA, and over the years I've had to change everything on it to handle lots of power. Would of saved myself a good chunk of change if I just started with a TT6. In hindsight I should of done it that way round, so might not be a bad idea for you. Especially if you ever want to push the power of the car beyond stock.

A little offtopic. As I am far away from UK and wont be able to get a TT box. Maybe I can buy from David P already built auto box for NA-T applications?

There are many different ways to incorporate the stronger TT box for N/A-T and for me to establish which method is best suited for each application, is waaay beyond communication with text or pm grunts and requires talking in old money.

Because the end result can only be as good as the used components, I leave the responsibility of acquiring these to the N/A-T-er.

Some of the scrap that is brought to me in expectation of achieving the next to impossible for the mostly ungrateful, is quite remarkable.

I believe the standard tt box can handle 550 bhp

Mine started as an NA, and over the years I've had to change everything on it to handle lots of power. Would of saved myself a good chunk of change if I just started with a TT6. In hindsight I should of done it that way round, so might not be a bad idea for you. Especially if you ever want to push the power of the car beyond stock.

Yeah, only problem is buying a TT6 now is crazy money. If i did swap, id be looking at a standard twin turbo auto or 5 speed but as i say, im reluctant to part with the car ive got because its such a good one. If only i had a bigger garage, id whip the engine and box out myself as a project at my lesuire but with limited space im snookered.

If you went for a NA 5 speed, you'd end up in a similar boat as you'll find people saying the w58 transmission can't handle much more than 400bhp reliably...

Better option could be finding a facelift SZ-R? They came with the v160 6 speed transmission and the 2jz-ge. Much cheaper than a TT6

Yeah, only problem is buying a TT6 now is crazy money. If i did swap, id be looking at a standard twin turbo auto or 5 speed but as i say, im reluctant to part with the car ive got because its such a good one. If only i had a bigger garage, id whip the engine and box out myself as a project at my lesuire but with limited space im snookered.

If you discuss with David and need a TT box I have one I'd be willing to part with (I don't think it's a straight swap but you can use it or parts of it - but best researching/talking to David etc)

In fact I have a NA gearbox too (bought by mistake!) that perhaps then you could create a hybrid box from at your/David's leisure and then you could carry on with your NA-T plans knowing you have a backup if (when!) your gives up?