Jump to content
The mkiv Supra Owners Club

Stock trac control issues with BPU anyone solved this?


StuartW

Recommended Posts

  • Replies 65
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

I don't know about the pre-facelift Supras but when I turn off my T.C. it still has stability control that cuts in, as and when, without any loss of power or untoward side-effects. You just see the flashing yellow warning light with skidmarks on it momentarily, if you spin a wheel on a corner. It never ever steps out of line, (unless I try drifting in the wet on roundabouts but even then, I've never felt about to lose it).

 

It's always the left rear that lets go when accelerating though; is this normal? Should be a type 2 (torque sensing) LSD according to 1997 spec's? I've always figured that the extra weight on the driver's side causes this.

 

Maybe fitting a facelift T.C. system with this extra stability program would help? That is, unless they're all the same and the extra power you guys run, still makes it shut down the throttle, even with the T.C. off?

Link to comment
Share on other sites

I love not having any traction control. I think if I did, I'd just turn it off every time I drove anyway.

 

I always do.

 

The slightest slip of a wheel, (driving over a bump, for example), can trip it into shutting down power. More annoying than dangerous though, as generally, it only comes on under way too much throttle on the road, hence, always turning it straight off! :D

 

It's one of those driver assists that if not done properly, is worse than nothing atall, like the ABS itself.

Link to comment
Share on other sites

Moved out of Technical in to Off Topic. If Stuart does the modification to the butterfly I will remove the chit chat and put it back in technical.

 

So what does this modification involve exactly? I mean, surely it will totally bugger up the idle. The slightest leak through a closed butterfly will raise the idle speed. Are we talking a secondary throttle, behind the main one? If not, you're properly into bodge job territory and either way, it's hardly the ideal solution.

Link to comment
Share on other sites

It is an extra butterfly in the manifold which simply snaps shut when the traction control system senses slip (on the j-spec anyway).

 

Stuart's idea is that rather than having the thing snap shut and stop all airflow it can be cut down to allow some airflow to go through without killing the car dead.

Link to comment
Share on other sites

It is an extra butterfly in the manifold which simply snaps shut when the traction control system senses slip (on the j-spec anyway).

 

Stuart's idea is that rather than having the thing snap shut and stop all airflow it can be cut down to allow some airflow to go through without killing the car dead.

 

That would take some tuning to get it right, (let alone multiple removal and replacement of the manifold gubbins) and it would only be right under certain circumstances. At another time it might kill you. No worse than stock though, I suppose! :D

 

Can't the butterfly motor electrics be resisted to perform the same job with a pot' to allow adjustment or am I repeating what's already been done countless times? Electronic intervention would be far superior to hacking a lump off the flap, as too much and you might as well remove it or replace it. You'd also have in-car adjustment with a manual potentiometer. I guess that's why RLTC was developed, huh?

Link to comment
Share on other sites

Not much has ever been tried with the stock TC, which is why people used to fit RLTC, remove the stock butterfly and fit blanking plates as the RLTC system is so far ahead of stock TC it reacts even before the stock TC knows there is a problem.

 

Not sure why Stuart doesnt trust RLTC but will be interesting to see what results he can get with his idea.

Link to comment
Share on other sites

Not much has ever been tried with the stock TC, which is why people used to fit RLTC, remove the stock butterfly and fit blanking plates as the RLTC system is so far ahead of stock TC it reacts even before the stock TC knows there is a problem.

 

Not sure why Stuart doesnt trust RLTC but will be interesting to see what results he can get with his idea.

 

Yes, thanks for the info. :)

 

Like I said earlier though, my facelift T.C. still works to prevent slip even when turned off. Was wondering what difference there was to Stuart's T.C.? Mine's a '97 model TT VVTi so it goes into snow mode really easily but when turned off it still has some sort of E.S.P. to limit wheelspin to a mere twitch at most. I vaguely recall it being yaw sensing from somewhere. Certainly hasn't ever let the back end out very far. Knocks that straight on the head.

 

Edit; When I say limit wheelspin, I mean during any yawing motion, as in an imminent spinout on a corner. You can still rag the crap out of your tyres if you want to with T.C. turned off. Must have anti-spin like my Smart Fortwo.

Link to comment
Share on other sites

Yes, thanks for the info. :)

 

Like I said earlier though, my facelift T.C. still works to prevent slip even when turned off. Was wondering what difference there was to Stuart's T.C.? Mine's a '97 model TT VVTi so it goes into snow mode really easily but when turned off it still has some sort of E.S.P. to limit wheelspin to a mere twitch at most. I vaguely recall it being yaw sensing from somewhere. Certainly hasn't ever let the back end out very far. Knocks that straight on the head.

 

The VVTi TC system is better than the pre-facelift version - and the RLTC is miles better than both.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.