[supravan92]

Here's what I'm about to order:

Intercooler with 3" piping and SSQV BOV
4" HKS Ti exhaust, 3" HKS downpipe
and probably going to get a boost gauge as I don't have one yet.

also will stock ECU be fine?
and this is a J-spec Supra so should I upgrade my injector size?

My stock j-spec dyno'd 315bhp STOCK... and I am aiming at a reliable 350rwhp, the car is my daily driver.


what else do you recommend for 350rwhp? or what I have should be fine?
I know most people go up to 18psi but will that be practical as a daily?


thanks

 

[xnofear6988x]

u should be perfectly fine. I dont see a need for aftermarket injectors or a diff ecu. 18psi is fine for a daily driver as long as ur not at wotm every day. Your setup should be good enough.

 

[95jza80tt]

I am not totally sure but I thought there was an issue with the JDM supras overboosting due to a restrictive internal wastegate port or something to that matter so when you change your dp and exhaust to something that is very free flowing overboosting and or boost spiking is something hard to avoid. That is why some of the other fellows with the jdm spec supras run restrictor plates because their exhaust setup flows too freely thus naturally raising the boost. Not to mention the ceramic wheel designs of the jdm turbos tend to grenade them when constantly running high boost. Do more searching as I am not completely sure of these issues since I have only had experience with the usdm supras, but these were a few things I have noticed when lurking around on some of the other sections of our forum.

 

[want2boost]

i know for mine, i did an aristo swap, so it should be the same, i did the fmic, and a full 3" DP to a 3.5" exhaust, and i cant keep it from hitting fuel cut, i can still drive it but when i run it overboosts, just my .02

 

[supravan92]

ok is there a gauge that I should get then to watch the fuel cut? boost cut controller?

I am all new to the turbo scene, all my cars in the past were n/a

 

[RyanV]

I personally wouldn't run that much boost on 15 year old ceramic turbos. It's ok if you plan to do a single upgrade in the near future. I'd keep it at about 1.0 bar since I think that's where you get fuel cut on the stock set up anyway.

 

[want2boost]

i mean a gauge is important but it wont fix fuel cut, ive heard that restrictors will fix the problem, im not 100% sure but i think the boost cut controller wont work right on j-spec car because we run off our MAP no MAF, so im under the impression it will just run lean anyone correct me if im wrong. My twins are going out so i am just going single, that way i can control boost easier

 

[bodilx6]

There is a few issues here:
If you decat your exhaust completely, you will hit fuel cut @ 1 bar. You can use a boost controller or a Fuel Cut Defender to remove that barrier. But at that point your turbos WILL overboost massivly and they will go boom. You need restriction in a j-spec decatted exhaust since the wastegate is too small to keep the boost controlled.

Two ways of getting to this; easiest is to insert a simple plate with an aprox 50mm hole. This should keep you in the 1-1,2 bar range. The exact diameter can differ a bit from car to car/exhaust to exhaust. The other way is to keep the 1st cat in and knock a hole through it, keepeing a bit of restriction in here. This has to natural advantage that you can point to the cat, should you need it for the car to be legal. It will not keep up to emission regulations, but it will be ok to satisfy police.

A boost gauge is MUCH reccomendend until you have the setup done and know you dont boost past the 1,2bar/17-18psi. You should not have any trouble daily driving at 18psi. I've been running 1,2 bar for 5 years now. No issues. But of cause depends on how you use your car. I do track it once in a while and even take it around the Nürburgring a few times a year and everything is holding up nicely.

You will not need new injectors, but a fuel pump could be a nice "safety net" as you will be hitting around 400 hp @ flywheel

PM me if you want more specific info

 

[Hatem]

Hey supravan92,

Here's a list of what you could do in order to achieve some nice numbers on BPU levels:

- Air intake

- JDM downpipe!!! Make sure it'll bolt on the JDM twins. http://www.supraforums.com/forum/showthread.php?501581-JDM-Downpipe&p=8139358&highlight=#post8139358
Or else u'll end up having something that'll look like this:

- Exhaust (U don't need a 4" if you're sticking with the stock twins... Unless you plan on upgrading to a single turbo later)

- Restrictor Ring so that your ceramic JDM twins don't over-boost. As JDM twins have a restrictive internal wastegate and won't be enough to keep boost at wanted/needed levels. Keeping in mind that the maximum amount of boost your JDM ceramic turbos could handle is 1,2 bar which is 17,4 psi. After that you'd be running the risk of blowing your turbos up.

- You will aslo need a boost cut controller (BCC) in order to overwrite the factory fuel cut of your ECU.

- A boost controller & a turbo timer would be nice as well.

- You could also throw in some pulleys, cam gears and a tensioneer bracket would be recommended.

- Maybe a BOV if you like the sound of it.

- USDM camshafts & 550cc injectors (not necessary, but wouldn't hurt either)
If you end up getting injectors, make sure they fit your JDM fuel rail as it is different than the USDM

- NGK plugs?

- As for gauges you will need a boost gauge and a wideband

- FMIC won't hurt + it'll look good

This should get you to anything between 350rwhp - 400rwhp reliably for a daily driver.

Good luck!

 

[supravan92]

Thanks a lot for the help guys, lots of new info for me here.

And I know I don't need a 4" exhaust I just like the sound of them.


I don't think I want to throw everything on at once, maybe order the exhaust and intercooler for now. With a larger exhaust this shouldn't cause fuel cut and overboosting right? this only becomes a problem when I install the downpipe? I just want to make sure i'm understanding this correctly.

If so and I get those parts I will look at JDM downpipe and go from there.

thanks again

 

[Hatem]

I think u'll be fine with just an intercooler & exhaust, even though I'm not so sure u'll be putting 350rwhp to the ground.
I used to hit the fuel cut @ 0,9 bar with just a down pipe & exhaust, so u might want the BCC as well.
Anyhow, u will need a boost gauge to know how much boost ur getting.
Also, if ur car is a LHD with the JDM engine & twins u'll have to get a regular down pipe but u'll need to cut the flange on the turbos side & weld the JDM flange (with 3 bolts just like in the pics above).

 

[supravan92]

Nope my Supra is full JDM

RHD with JDM TT engine.


damn didn't think I would experience any problems like this with very basic modifications.

 

[bodilx6]

I would not go for the intercooler. You will see no effect from that, if your SMIC is in good working order. If you want it for the bling, thats fine but it will do you nothing. I could go on and on about this, but the SMIC is such a nicely engineered part of the supra, with both correct ducting and nozzle to speed the air up again = less drag. Also in regards to low pressure zones around the wheel and so on. You will so no gain (probably the opposite if you were to measure it thoroughly) except the bling. - And you will have to loose your active spoiler, if you got it.I would reccomend a nice aftermarked full alloy SMIC instead. That should keep things nice and cool all the way to 600hp or so.

Also give the 4" some thought. They tend to "drone" a lot on the highway. So if you do a lot of cruising @ that speed it can get quite annoying.

But by doing just a cat-back and intercooler, you should not hit boost cut. If you do the entire exaust from the downpipe and back, thereby deleting the 2nd cat, you will hit fuel cut. With the 1st cat in place and full 3" exhaust I made 354hp flywheel so you will be around there as well.

 

[Hatem]

bodilx6 is there a particular aftermarket full alloy SMIC that u wld recommend?
I'd like to look into one of those...

 

[RikTT]

Invest in a Wideband

 

[cadmkiv]

hey,

I'm running a J-spec in almost the same spec you asking about. my recommendation is:

cat-back (whatever personal pref is)
Boost gauge
intake
BCC or Tuneable ECU (BCC is the cheaper option to start)
And only single de-cat to have some control on runaway boost. Single de-cat over both is about 10rwhp but it will save the twins life in j-spec.

*not needed but recommended - boost controler if not tuned ECU, Fuel pump(jspec gets pushed hard over 17psi)

and yes no USD/CAD supra downpipe/midpipe fit on the j-spec best thing to do is get custom made or risk you luck with suprastore online and get one shipped but its buyer be ware with them. I made this risk for only this part and it worked out fine for me.

Then down the road add FMIC, clutch , cam gears/cams, full de-cat and single ect.

i have been running mine at 17psi or about 1.1 kg/cm2 daily driven and its great.

good luck-

 

[Nick 95 6sp]

bodilx6 is there a particular aftermarket full alloy SMIC that u wld recommend?
I'd like to look into one of those...

The only one I know of still available is the Chris Wilson SMIC, he's a prominent, respected member/supplier on the UK Supra forums. There has been positive posted feedback about his SMIC but I don't recall actual comparative data stock SMIC vs CW SMIC. The CW is nice size, seems well made, and allows using stock duct work which is very important for optimized airflow.

stock on left, CW on right

 

[Hatem]

Thx Nick

WLd u happen to know his SF nickname?

 

[Nick 95 6sp]

on the UK forum he's "Chris Wilson". While I don't frequent that forum...I probably should visit more often, I think he's still quite active:

Price holds good from original post, and in stock, will reply by e-mail tomorrow, bit jaded from a heavy day at Oulton

Regards, Chris Wilson.

Race and performance road car servicing and preparation in north Shropshire. Race and road car engine building and tuning. Suspension development and geometry specialist, all Supra work and other cars too! Latest Bosch KTS and Vagcom diagnostics for all cars. 07971-952084 [email protected] NO PM's PLEASE!

 

[94Canuck]

Here's what I'm about to order:

Intercooler with 3" piping and SSQV BOV
4" HKS Ti exhaust, 3" HKS downpipe
and probably going to get a boost gauge as I don't have one yet.

also will stock ECU be fine?
and this is a J-spec Supra so should I upgrade my injector size?

My stock j-spec dyno'd 315bhp STOCK... and I am aiming at a reliable 350rwhp, the car is my daily driver.


what else do you recommend for 350rwhp? or what I have should be fine?
I know most people go up to 18psi but will that be practical as a daily?


thanks

List looks good.

Skip the 4", go with a Blitz Nur. +1 on the proper DP fitment, speak with AGM he knows the right one to get that won't need modification. +1 on the wideband. Stock ECU will be fine, so will your injectors. 18psi is perfect, no issues there and 350rwhp is great for a daily. Lots of go, without a bunch of hassles. BPU is where it is at! I wouldn't go the single route ever again if I had another Supra.