We have our old Supra back after 10 years! But it seems a bit slow... Info/Advice...

[Guest Stav Redline]

Hi there, Stav here, Deputy Editor of Redline Magazine here (You know, that one with Jamie P's car on the current cover!), hope you're all well.

 

Right back in 2001 we had a UK spec Mk4 Supra twin turbo auto as a project car, and since then Toyota UK themselves have kept it and looked after it. They have kindly lent it us back for a week, but the car seems far slower than it used to be. 'Maybe' its us, but something seems odd...

 

Spec is, from what we remember and can see...

HKS front mount intercooler

Blitz cat-back exhaust (ie the middle cat, so stock front/middle and downpipes)

Blitz cone filter (directly on to the AFM)

Superchip (Exactly what is involved here, we don't know, any ideas? BUT it has a bleed valve fittted?! But its wound fully shut it seems. Was the 'Superchip' conversion just a bleed valve in 2001?!).

Samco boost and coolant hoses.

 

Car seems well, no smoke, no dodgy noises, no missfires, can feel the shove when the 2nd turbo kicks in about 5k or so, but its pretty flat, esp until the 2nd turbo, and we're not even sure it's standard power?!

 

What power would the above spec likely be even with a stock ECU map?

Any idea what the 'Superchip' setup would be?

Whats maximum safe boost for it to run in this spec? (I will hook up a boost gauge later)

 

IF this is about how it should be at this spec, what would be the next step? Replacing that rear cat section with a free flowing item? Any links to the right part?

 

Any ideas, things to check, and so on, would be MUCH appreciated

 

Stav

[monsween]

Does it have a de-cat?

 

Safe boost is around 1.2 for j-specs and 1.4 for uks.

 

I wouldnt be trusting this superchip setup.

[Scott]

I would be very wary of the bleed valve and superchip. Have a look under the passenger carpet, up at the footwell to the rear of the dash. The ecu is in there, check for any strange boxes or writing on the ecu cover. Definitely bin the bleed valve, it's not going to do you any favours.

 

First thing to do is get a boost gauge on it, take her for a spin and see what she hits. After that check when the transition occurs, it should be 4k revs rather than 5.

 

Once you know all that is good it's time to get some boost into it. An electronic boost controller is best but if you insist on a mechanical valve then go with a ball and spring type. An EBC will set you back about £100 for a basic model 2nd hand. A mechanical ones will be around £20. Go for 1.3 bar on the uk turbos. That's the accepted limit before heat takes over.

 

If doing the above definitely ditch the 1st cat if it hasn't been already. 2nd one isn't so much of a restriction.

 

See how it feels then

[Guest Stav Redline]

1.4 on stock ECU/fuel setup? Thats a good start to finding out.

 

Doesnt have any kind of de-cat it seems, we had a quick look under the car and the Blitz exhaust starts around the middle of the car, just after what looks like a cat, and from there to the front of the car it's defo the stock system.

 

Will take a look at the ECU, but we suspect superchips just wanged a bleed valve on it!

 

Is there a link anywhere to where the boost controller should be fitted? The bleed valve seems to be in a vac line from near the rear turbos inlet to somewhere down near the front turbo? (I'll grab some pics later if need be)

Edited September 14, 2011 by Stav Redline (see edit history)

[The-Plethora]

Do you mean the car has just been stood around for 10 years or so? Probably needs it's fluids checking and a good long drive. With cats still in I am guessing anything from 323bhp to 350 with those slight mods. I wouldnt go increasing boost much if you still have the cats in due to the heat.

Myself and a few others are in and around Bristol but mines BPU but might be worth comparing things to see if the power is where it should be. Check those fluids and get some miles on it first I say.

[Geo]

Agree with Scott. But if you have the car for one week. Why are you bother with fault finding of it's going back to Toyota UK?

[j_jza80]

By the looks of it, you're not too far away from Whifbitz, SRD or AFR, who are all respected traders on this forum. I'd say the car is probably due a good check over by people who know these cars inside out (ie, not Toyota )

 

Welcome aboard by the way

[j_jza80]

Do you mean the car has just been stood around for 10 years or so? Probably needs it's fluids checking and a good long drive. With cats still in I am guessing anything from 323bhp to 350 with those slight mods. I wouldnt go increasing boost much if you still have the cats in due to the heat.

Myself and a few others are in and around Bristol but mines BPU but might be worth comparing things to see if the power is where it should be. Check those fluids and get some miles on it first I say.

 

Toyota have been using it for promo work, it's been to loads of shows and events, including Goodwood FOS.

[BOB B]

From your description it seems you still have both your cats in, if that is correct you will only be hitting 0.8/0.9 boost, though if it is the same as it was when you moved it on, and unless it has done big miles since then, it should feel relatively the same.

 

Never had a boost chip and I don't think many have, I don't think they are any good.

 

If you go full BPU (see FAQ IN TECH), you would get what monsween has said, though that is a Max.

[Scott]

From your description it seems you still have both your cats in, if that is correct you will only be hitting 0.8/0.9 boost, though if it is the same as it was when you moved it on, and unless it has done big miles since then, it should feel relatively the same.

 

Never had a boost chip and I don't think many have, I don't think they are any good.

 

If you go full BPU (see FAQ IN TECH), you would get what monsween has said, though that is a Max.

 

Cats won't make a difference to a uk spec with regards to boost levels though.

[Guest Stav Redline]

Its been looked after and used a lot by Toyota UK, no worries there regarding servicing etc, but of course, the tuning side of things they know nothing about, they would just treat it like a standard car.

 

It may or may not be the same as when we gave it to Toyota, esp regarding that middle pipe, as we could've swore it used to be louder.

 

So around 5k is a bit late for the 2nd turbo? Any ideas what would be causing this?

[Gaz6002]

Stick a boost gauge on it, take it for a run and have a play with the bleed valve if you're not hitting high enough boost. Just make sure you're not hitting too much boost with the cats in as the exhaust gas temps will shoot up.

[Brazil]

In for some pic's...!

 

Once you know for sure what its boosting I would take it to a dyno so you know for certain that you are getting the power that you should be getting.

[Branners]

Sounds a bit like its running true twin mode. On a UK spec they boost up a little late in TTC so would explain the boost coming in so high. The kick on a normal sequential would be around 3500 to 4000rpm.

 

TTC conversion is easy to do, theres a couple of ways of doing it so you would need somebody who has more of an idea than me to tell you how to check for it.

[Guest Stav Redline]

The second turbo comes in around 4.5k, which sucks on the motorway at certain speeds as unless in manual mode and revving the tits out of it, you end up before the 2nd turbo even after kickdown (which takes it to about 4k usually) which, to be honest, is pretty slow.

 

Ill go find a boost gauge to plumb in now...

[mellonman]

have a look here tells you all about the stock turbo set up and ttc

http://www.mkivsupra.net/vbb/showthread.php?35926-The-sequential-system

[Tyson]

Hi Stav, we have a UK spec register on here it would be great if you could add this one !! Oh an welcome back The link to the register is below in my signature.

[Guest Stav Redline]

Right, hooked up a boost gauge and...

 

0.9bar or so.

 

Undid the bleed valve a turn, 0.9bar or so, undid another turn, 0.9bar or so.

 

SO rather than keep trying, I took some pics, looks like all manor of things going on here...

 

The bleed valve is above the rear turbo, off a line that goes from the inlet pipe near the rear turbo, and theres a solenoid valve next to it that's been bypassed, which, am I right in saying is the VSV for the rear turbo wastegate actuator? Looks like some lines above have been looped too.

 

The other side of the bleed valve travels to the TOP port of the front turbo wastegate actuator, and ANOTHER VSV looks to have been bypassed, this one is the one for the front turbo, right? Just out of shot you can see the line coming from the bleed valve to the actuator has been joined where there was originally a break in the line- We presume where the front VSV was originally plumbed in?

 

SO, I'm confused, lol. How the hell should it be plumbed in?! It needs its boost back and the 2nd turbo not kicking in for so long is a bit rubbish too and probably connected to this issue...

[Scott]

Wow, that's not right at all. I would definitely take out the bleed valve and plumb it back in the way it should be. The VSV should definitely not be bypassed.

[monsween]

Wow, that's not right at all. I would definitely take out the bleed valve and plumb it back in the way it should be. The VSV should definitely not be bypassed.

 

I think that VSV does get bypassed when adding a boost controller.

 

I think its plumbed into the wrong turbo however (does that even matter?)

[RobD]

When I see it in Surrey they moved it a couple of times, all for about 100 yards or so at a time! I'd advise a good service, fresh fuel and maybe it could do with an ECU reset

 

EDIT: and those pipes look a work of art! definitely not right! I'm surprised Toyota didn't notice something wasn't quite right there!

Edited September 14, 2011 by RobD (see edit history)

[fastcar]

the VSV for the 2nd turbo shouldnt be bypassed! only the VSV for the 1st turbo should be bypassed when connecting a boost controler. Not sure about a bleed valve but im sure it works the same way.

looks like a bunch or ametures have been messing with your pipe work so i would think Toyota is to blame for that mess!!

[Guest Stav Redline]

Im a bit confused to be honest.

 

The rear VSV being disconnected makes no sense, I agree, but the front one, if being changed for a bleed valve to up the boost, does make sense I guess.

 

BUT the bleed valve feed looks like its on the inlet side? There will be no boost there, will there?

 

What would the reason/effects of the rear VSV being disconected be?

 

I bet the 'superchips conversion' was just a way of bypassing the fuel cut (if theres one on a UK TT?) plus a bleed valve, esp as it was a decade ago. I expect they realised the stock ECU can cope with upto 1.4bar so just used a cheap bleed valve to do so.

 

BUT the reason its such a mess now is potentially Toyota (not knowing tuning at all) getting confused which pipes were meant to go where after they'd taken bits off repairing something...?

 

Sooo, how should it all be linked up? Esp the rear VSV, the front bit looks more obvious...

 

(PS- Oil is fresh, as is fuel, and I bunged in a bottle of octane booster just to be sure...)

[Scott]

I think that VSV does get bypassed when adding a boost controller.

 

I think its plumbed into the wrong turbo however (does that even matter?)

 

No wonder your boost gauge didn't work

[Scott]

Im a bit confused to be honest.

 

The rear VSV being disconnected makes no sense, I agree, but the front one, if being changed for a bleed valve to up the boost, does make sense I guess.

 

BUT the bleed valve feed looks like its on the inlet side? There will be no boost there, will there?

 

What would the reason/effects of the rear VSV being disconected be?

 

I bet the 'superchips conversion' was just a way of bypassing the fuel cut (if theres one on a UK TT?) plus a bleed valve, esp as it was a decade ago. I expect they realised the stock ECU can cope with upto 1.4bar so just used a cheap bleed valve to do so.

 

BUT the reason its such a mess now is potentially Toyota (not knowing tuning at all) getting confused which pipes were meant to go where after they'd taken bits off repairing something...?

 

Sooo, how should it all be linked up? Esp the rear VSV, the front bit looks more obvious...

 

(PS- Oil is fresh, as is fuel, and I bunged in a bottle of octane booster just to be sure...)

 

 

Ok for the one at the back of the engine....

 

The bleed valve needs to be taken out and a fresh pipe put in its place. The "in" and the "out" are OK.

The LHS port of the VSV (as you look at it on the picture) connects to the LHS pipe on the loop.

The RHS port of the VSV (as you look at it on the picture) connects to the RHS pipe on the loop.

 

 

Do you have 2 bleed valves? I can't see from the 2nd picture.

 

Anyway, in the 2nd picture you can see the actuator at the back. It has 2 hoses coming out of it. One should be going to the turbo outlet and the other should be going to the VSV. I can't see where the one pointing downwards is going but it is useless to the setup. In order to fit a boost controller the actuator needs to be blocked off at that point. The upper inlet from the turbo is where the boost controller needs to be fitted. The outlet of the turbo manifold goes to the "in" port of your boost controller (mechanical or electrical) the out port from the boost controller goes to the top port of the actuator.

 

There should also be a line on the vac lines at the top of the engine blocked off. When you look at the vac hardlines there will be 2 tailing off to the LHS of the engine as you look at it from the front. The left most one gets left as is, the right one is the one that would be going to the VSV that you are bypassing. This gets blocked off.

 

It's hard to explain just in words and I don't have a complete Supra to take pics of anymore so I hope that helps