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The mkiv Supra Owners Club

tuning standard supra twin turbo


Guest beefycol

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would probably be a good idea to do other (boring) jobs first before hitting the bhp route. maybe get the car FULLY serviced (cambelt, lsd fluid, 'box oil, fuel filter etc), get the valve stem seals and turbo seals done, maybe replace the intercooler (if it hasnt already been done). get the car dyno'd in stock form, make sure its running sweet as a nut, then do the performance mods.....will probably save time, tears and money in the long run. these cars, however reliable, are cracking on a bit :(

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The standard power of a j spec TT is 320bhp. 280 is rubbish and was only claimed by Toyota because of said gentlemans agreement between the manufacturers limiting power to that amount at the time. I've had two different completely standard low mileage j spec TT's dyno'd at 321bhp and 323bhp respectively.

 

Check out all the threads on BPU on the forum for full details of what parts but really you're looking at 400bhp max at the fly with standard turbos. Beyond that you are as well to go single turbo.

 

Don't bother with larger injectors - the problem these cars have is too much fuel as standard with AFR's in the 10:1 range and under when on the 2nd turbo. A piggyback or replacement standalone ECU is a good idea to optimise your setup at BPU but by no means essential.

 

In my opinion the things you should buy for BPU (assuming std IC in good condition and car well serviced / running fine) are:

 

1. Aftermarket exhaust - Blitz Nur Spec R my preference but dozens will do the job well with differing levels of noise.

2. 2.5" Decat pipes

3. Restrictor ring to limit boost to 1.2bar

4. NGK BKR7E or BCPR7ES spark plugs gapped down to 0.9mm or just under

5. Walbro 255LPH fuel pump or new UK spec pump from Toyota

 

That's it!

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Guest verbal

Back in the day all the japanese manufacturers came up with a gentlemans agreement because things were just turning into stupid HP wars, the agreement was to limit the vehicles to 280HP, nobody really followed that agreement, each manufacturer published 280HP but people have dyno'd the supras and skylines of the day and they were producing well over 300HP.

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The difference between the jspec & ukspec from what i have seen is the actual power delivery is somewhat different although their bhp is similar. As for going over say 390 bhp (although all cars differ) i would think piggyback ecu, could make 420 bhp achievable.

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Unless you want to be disappointed, the J spec is 280bhp. As I said, anything more is speculation because there has never been a published account from the manufacturer. If your Supra has 320bhp then you're lucky... same as some of the BMW M series cars fluctuating by around 50bhp from the factory. I'm sure some J spec Supras did come with 280bhp, if only the early models.

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Unless you want to be disappointed, the J spec is 280bhp. As I said, anything more is speculation because there has never been a published account from the manufacturer. If your Supra has 320bhp then you're lucky... same as some of the BMW M series cars fluctuating by around 50bhp from the factory. I'm sure some J spec Supras did come with 280bhp, if only the early models.

 

Well with a bit of luck then, my Supe came with 320 bhp from the factory... :-D

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Unless you want to be disappointed, the J spec is 280bhp. As I said, anything more is speculation because there has never been a published account from the manufacturer. If your Supra has 320bhp then you're lucky... same as some of the BMW M series cars fluctuating by around 50bhp from the factory. I'm sure some J spec Supras did come with 280bhp, if only the early models.

 

Rubbish.

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Does that mean that the VVTI's are higher than 320? They apparently have a mythical 25bhp more than a standard Jap car, so does that equate to me having 345bhp before mods....? doubtful I think.

 

25bhp higher in the mid-range maybe, but I don't think Toyota ever officially said they were 25bhp higher than the non-VVTI.

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Guest beefycol

lol this post gone off the subject, i read on serveral websites that its 280, and serveral that its a myth and its 320. people have had like said 320 from the factory. what ever is true i just hope mines 320.

anyway the mods im going to be doing are

fuel pump,

colder spark plugs

decat, resistrictor ring

boost controller

dump valve

piggy back ecu

service

fuel cut defender

induction kit

 

 

then when i got some spare money front mount intercooler and short shifter

 

i was reading the BPU and it says resistrictor ring because the small size waste gate, on the uk model you dont need a resistrictor ring because it had got a bigger waste gate.

well if ive got a after market waste gate on will i still need a resistrictor ring? plus im goin to put a boost controller on would i still need one because you can control the psi boost with the boost controller?

Edited by beefycol (see edit history)
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You can't use an aftermarket wastegate with the standard internally gated setup unless you go to a lot of expense and time taking the turbos and manifold off to extensively modify them.

 

I wouldn't bother with a boost controller - the point in the restrictor ring is to limit boost to a sensible level. Size it correctly and there's no need for a boost controller as you'll be at the highest boost level you want to run and they cannot lower boost.

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Guest beefycol
You can't use an aftermarket wastegate with the standard internally gated setup unless you go to a lot of expense and time taking the turbos and manifold off to extensively modify them.

 

I wouldn't bother with a boost controller - the point in the restrictor ring is to limit boost to a sensible level. Size it correctly and there's no need for a boost controller as you'll be at the highest boost level you want to run and they cannot lower boost.

 

ok cheers that save me some money then. take the boost controller off my list.

please check my new post need more help https://www.mkivsupra.net/vbb/showthread.php?t=160028

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  • 1 month later...
I have to agree. There have been several standard J-Spec's dyno'd right around 320BHP, they were never 280.

 

The previous owner of my car had mine dynoed at 326bhp with the only mod a front downpipe; so I do think most j Specs are around the 320bhp mark.

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Be warned though, you will always have your hand in your pocket once you go single...

 

I have to disagree, if you ask me it comes down to what parts you use, quality of install, who tunes it and how its maintaned. Like any car though something will go wrong but if the jobs done proper it shouldn't be major expence.. Cost you a fortune in fuel though!

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I wouldn't bother with a boost controller - the point in the restrictor ring is to limit boost to a sensible level. Size it correctly and there's no need for a boost controller as you'll be at the highest boost level you want to run and they cannot lower boost.

 

I agree. The aftermarket BC was the biggest waste of time and money I've ever done, although at the time I thought I was doing the right thing. If you're going BPU you really don't need it. It can control the boost upwards, but lets be honest, once you've decatted it, done the induction and got rid of the fuel cut, all you really need to do is keep the boost from running away, and a BC is no good for limiting Boost, only increasing it. Get a nice 1.2 bar RR and enjoy :) Save the BC for later. You'll know when. :D

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I have to disagree, if you ask me it comes down to what parts you use, quality of install, who tunes it and how its maintaned. Like any car though something will go wrong but if the jobs done proper it shouldn't be major expence.. Cost you a fortune in fuel though!

Posted via Mobile Device

 

That is true however ask a member who has gone single, Pig, Gaz 1, tooquicktostop, Jamie P or even Chris Wilson, they'll tell you exactly how much it costs to build,

run and maintain...

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Guest redsupra31

hi all,

 

Just some info. input & also professional advice. TQ.

 

My UK Spec Supra TT VVTI Auto-Tiptronic boosting 1.1bar is getting 330 bhp/43.8 kg/torque on wheel.

 

Modification - ARC intercooler, ARC BOV, HKS spark plug (7), HKS air filter, HKS oil cooler, HKS auto gearbox oil cooler, ARC power steering oil cooler, HKS FCD, APEXi Boost Controller. Others all factory standard.

 

Plan to Upgrade - Greedy E-Manage Ultimate & HKS Valcon V-Cam (inlet & exhaust). How many bhp can i get???

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