[LJZ]

Slowly but surely I am working my stock MKIV supra upto a nice little street monster. Just doing little bits and pices at a time, DYI where I can as i love playing around with it.
I have always wanted to keep the stock turbos, maybe get them highflowed and have the boost run upto around 18psi.
After reading loads of threads about BPU I have worked out that the following needs to be done to acheive 18 psi safely.

So far I have;

1. Aftermarket catback exaust - Check. Mine came from japan already with a 3.5" catback system.

2. Front Mount Intercooler - Check. At the end of last year I bought Noodles' FMIC kit with hardpipes and fitted it.

Things I dont have yet;

1. BCC - bypasses the ECU from cutting power when boost goes over 14-15psi

2. Colder grade spark plugs - Iridium IK22 or NGK BCPR7ES plugs, smaller gap aparently for overboosting applications

3. Electronic Boost Controler - Prolific B 2 i was thinking, something around this price point. I really want to have this so that I can protect the car from overboosting and have more control.

Here is my main question
4. Decat

I am a little unsure what to do here, keep in mind I want to keep this thing street legal. Alot of forums and threads suggest to decat the whole system but i know that this would be a big no no as far as regency park is concerned.
What is a good brand for downpipe, midpipe & highflow cat system I can purchase?
Or will I have to get a custom system made up.
From reading threads I was thinking of getting a 3" decat front pipe,
a restricter plate 2" between this and a 3" midpipe with highflow cat.

Is this how I should do it? any suggestions would be great.
What have other people done to their exaust to overboost.


Cheers, Luke

[ma61turbo]

It's a Profec not a Prolific ;)

If you put a 2" restrictor in you won't get 18psi. I'm running a 2" dump/mid pipe and I'll get 1bar boost max, 2.5" is closer to what you want although I'm not sure that'll get you 18psi.

Without going a full custom job, the Tuneagent 3" dump and midpipe kit seems to be the best option these days, I assume it is still available. Forget no cat, it makes SFA difference anyway as long as you put a decent 3"+ high flow cat on there.

Just be aware that although lots of people consider it "safe", running 18psi all the time is not conducive to long lasting turbos. Also, the more boost you run, the more the sequential system shows its downsides.

Ninja Edit: A boost controller won't protect you from overboosting, they can only help you run a minimum boost level. The only way to stop overboosting is by using a restrictor on the exhaust.

[LJZ]

haha and to think this whole time I have been calling them prolific B :whistling:

Thanks for the great info, that has made it alot clearer for me.

So there is there no other way than a 2" restricter plate to stop the turbo's overboosting??
I thought that the way a EBC worked was that you programed it with a preasure ie. 18psi and when the intake manifold reached this preasure the EBC solinoid opened the wastegate. Therefor releasing all preasure after 18psi stopping the overboosting problem, is this not right??

I wasn't going to run at 18psi the whole time, with the "prolific" EBC there are 2 boost settings so I would only switch to the higher for a bit of fun every now and then.

I checked out the Tuneagent 3" dump and midpipe kit online but the store is no longer trading. Bummer becuase it would have been PERFECT for what I want.
I still cant find any kits going around that will just bolt on, i think im going to have to go custom.

I know the local exaust guy down the road pretty well, do you think it would be worth going down there and getting him to make me up a 3" system with a single 3" highflow cat? If so should I supply the cat and adaptors or let him soruce it all.

Sorry for all the questions, not my field of expertease

[ben12a]

In my experience a boost controller does exactly the opposite of what has been said here. You can control your MAXIMUM boost level, by controlling when and by how much the wastegate opens. A classic example is the old bleed valve type of boost tee.

Unless there is something caused by all that sequential trickery on the 2J. I have never bothered to learn how that setup works.

If you plan to put a 2inch restrictor in the exhaust, then do not waste any money on the rest of it. Exhaust gas will only flow as fast through the whole system as it can flow through the 2inch restriction. (assuming the 2 inch restriction is the most restrictive part of the system). Of course there is some science in having a massive dump pipe for fast initial spool up (ie low restriction of the exhaust wheel) but over all power will hurt as the engine (when considered as an air pump) can only flow so much through a certain restriction. It is generally accepted in most Jap cars that the exhaust is a major restricting factor in the entire system, closely followed by the airbox (in some models).

By fitting dumps, a better flowing exhaust (with a bigger cat) and opening the factory airbox in my 1J I gained several pounds of boost, more power and more important to me, had a more responsive engine.

Boost cut was taken care of with an $80 second hand Greddy FCD.




Also, a mate sent me a link for munro racing turbos who are doing a range of rebuilds and hiflows for the 2J sequential setup that might be exactly what you are after. I'll see if I can find it.

This post has been edited by ben12a: 04 March 2011 - 05:37 PM

[ben12a]

"I know the local exaust guy down the road pretty well, do you think it would be worth going down there and getting him to make me up a 3" system with a single 3" highflow cat? If so should I supply the cat and adaptors or let him soruce it all."


Yes. I made my own on both cars. If your mate is a decent tradie, he can design and fabricate a decent system for a good price. The only concern would be 'drone'. Once again, if he is any good, he'll be able to sort that out as well.

Basically with a turbo system, you want the least restriction possible, so there isn't too much mystery in the design. Smooth bends (mandrel if you can afford it), decent diameter pipes (not to small, not too huge) and good quality mufflers and Cat. The less twists and turns the better.

[ma61turbo]

ben12a, on 04 March 2011 - 05:34 PM, said:

In my experience a boost controller does exactly the opposite of what has been said here. You can control your MAXIMUM boost level, by controlling when and by how much the wastegate opens. A classic example is the old bleed valve type of boost tee.

Unless there is something caused by all that sequential trickery on the 2J. I have never bothered to learn how that setup works.

Yeah, that's how they are SUPPOSED to work. Unfortunately with the sequential system on the 2j it has one wastegate on turbo number 1 and it is way too fucking small for controlling boost properly. If you chuck a 3" dump + zorst on it you'll get boost spikes of 1.5bar or more.

So, the way to do it with a 2j with sequentials is to put at most a 2.5" dump on it, if you got to a 3" you'll need a 2.5" restrictor(beats the point of a 3", but nobody makes off the self 2.5" dumps). You then use the boost controller to get up to your desired boost level as soon as possible, you can't really control the maximum boost as the small size of the wastegate can't flow enough gas.

Those munro turbo mods looks pretty good, and he has been working with a guy on the national forums for a while now perfecting a larger wastegate on number 1 turbo so they can be highflowed decently, but there still isn't much of an increase to be had. I think they can get reliable control for 18psi but that is about it. Pricing looks really, really good. Personally I think a decent single setup will get you better performance, but it will also cost more to do properly, and is rather obvious if someone pops the bonnet.

EDIT: And seeing as Ben mentioned the airbox, don't bother replacing it. Grab a TRD filter and you are good to go. Kim(Ultra_Supra) did some back to back testing on the dyno with and without an airbox and it made no difference if I recall correctly(was a few years ago).

[ben12a]

I figured that sequential setup might have been an evil thing once you want to modify. No one kept it on the Rx-7s either.

I guess the beauty of the high flowed singles, especially in this state, is that it looks legal. Well, it is legal, I guess. "Stock turbos?" Check. "Big blow off valve?" Nope. "Well then, I guess you can go. Have a nice evening, sir."

With the Soarer, most of us just open up the front of the box and remove some of the internal baffling at the rear. Our airbox is a bit of a restriction as it breathes through a tiny little snorkel. I also have the JZZ30/JZA80 TRD panel filter. Allegedly the stock filter when clean has a better flow/filtering correlation than most everything on the market.

[LJZ]

Thanks for the imput guys, this is exactly the information that I need to know.
After looking around on the internet for literaly hours and hours all there was were contradictory statements everywhere and nobody actually explaining their so called reasoning for things.

I agree with you Ben in that I coudln't see why everyone online was suggesting to get 3" pipe system and then block it up with a 2" restrictor ring. I mean doesn't that completely render the 3" pipe useless and may as well have stayed stock.
But Now I get it with the 3" and 2.5" ring due to the lack of 2.5" systems.
Its all falling into place now.

Quote

Also, a mate sent me a link for munro racing turbos who are doing a range of rebuilds and hiflows for the 2J sequential setup that might be exactly what you are after. I'll see if I can find it.

Ben that would be great, im very interested please let me know as soon as you find out more.

I have an Apexi pod filter, fitted before I bought the car but as I have put a FMIC on with hardpipes now the hot side of the intercooler piping goes streight over (touching) the pod so im loosing power there im sure.
I want to build custom box for that front section then run some airflow piping from the front right side of the front bar where the stock intercooler used to go.
I will have to extend the Intake pipe to do this which is no problem.

As for the exaust I will go talk to my local guy. he is very good as he used to design exaust systems for another company and now has gone out on his own. done it his whole life i think.
I will have a good chat and see if he can make 3" system with a 2.5" restrictor ring.
The only reason I say this is maybe one day I will want to run more boost and if i get a 2.5" system made up to start with then i will have to replace the lot. rather than just pulling the ring out.

Still a little unsrure about the type of EBC i want to get.
I am looking around the $400 mark on ebay, give or take a few bucks and have narrowed it down to 4 models i like.
I really dont want to make the wrong decision and later regret it. I hate that feeling of "ahhh man i knew i should have gotten the other one.
Any thoughts guys???

Turbosmart eboost street $427

AEM Tru boost $374

HKS EVC S $449

Greddy profec B spec 2 $395

The one i am leaning towards is the turbosmart eboost street. I just like the look and after alot of resaerch i think its the best.
But would like to hear some other opinions on it.

Cheers for all the imput guys, much apreciated

[ben12a]

http://www.munroraci...ce.2jzct20.html

I have never used an electronic boost controller. In the Rx-7 I made do with a bleed valve. I never wanted to mess with it because if you decide to wind the boost up, you really ought to get it tuned again. It'd be too tempting with the dial right there at arms length. Having said that, the eboost seems to be very popular and you don't hear of blokes having issues. You'd have to imagine the little brother 'street' version would be reliable too.

In the Soarers I am happy with the road car as it is, and in the race car I have left the motor alone as I am still running the stock, untunable, computer with some signal benders to remove speed and boost cut. I am in the market for a mid sized single turbo, likely a GT3076r and then some management to go with it.

This post has been edited by ben12a: 05 March 2011 - 07:22 PM

[LJZ]

Thanks for the link Ben, I had a look and those prices are really, really good.
I am very keen to get onboard.
As much as I would love a single turbo conversion there is just something about the stocker supra TT setup that is like a work of art and I would like to see how much I can get out of it by keeping it in its true form.

Quote

I never wanted to mess with it because if you decide to wind the boost up, you really ought to get it tuned again

After reading this you have me thinking maybe a EBC isn't the way to go. For one I would have to hide it in the cabbin anyways because if the cops see it then off to regency for me.
Plus the only reason I wanted one in the cabbin was so that I could switch between 2 boost settings, one for regular daily's and anothe for a bit of power. But would you say that this switching between different preasures would put the tuning out of whack?
If this is the case I would rather just have it set to a single preasure, get it tuned and then leave it at that.

With all this new information I am going to email munroracing and find out about their hiflow systems for the CT20's. Ask them about what they would reccomend to be the best setup for a downpipe/midpipe highflow cat and get that made up. Then later down the track can send the turbo's to them to get a full work over.
I am also going to have to get a BCC, I will get the car tuned at Fours and More with brenton and get him to fit a manual boost controler and tuned at the same time to make sure everything is in check.

Cheers for the help

[ben12a]

I don't mean for you to shy away from an EBC. If you want two boost settings then it is the way to go, one for business and one for party(like a mullet,LOL). You would, in my opinion, need a computer capable of holding two tunes, or able to make adjustments in line with the boost. I haven't kept up with recent developments. My last computer was a Microtech in a 12ATurbo. I am sure that this is well within the capability of any of the new units on the market.

Best thing to do is choose a tuner and go and talk to him about what you want, and see where he takes you. If you don't like what he is saying, go see a different tuner. I intend to find a tuner, buy whatever computer he is comfortable with tuning and go from there (as long as it is fairly widely supported computer- remember I did have a microtech).

I am also talking to Glenn at Munroe Racing Turbochargers about doing somethnig for the track car, because at $1250 for a pair of highflows, I can probably afford that in the short term whereas the GT3076r and all the associated parts ($4000-$7000) is going to take me a while to save for.


*edit* Just remember, nothing screams "defect me please" like aftermarket engine management. My Microtech was boldly labelled 'For Racing Use Only' across the front. I mounted it under the glovebox in plain view. The things you do when you are young...

This post has been edited by ben12a: 07 March 2011 - 07:17 PM

[LJZ]

Quote

one for business and one for party(like a mullet,LOL).

This made me seriously laugh out loud. great call haha.

All good info Ben, I will have to have a good chat to you on a club meet n great, cruise or whatever.
Are you coming out to the cruise this sunday?

[ma61turbo]

Or instead of high/low boost settings just don't press the loud pedal down too far ;)

A boost controller could possibly be a good idea, but with the sequential system(assuming you are planning to keep it as such and not run in true twin mode), boost comes on pretty quickly once you put an exhaust on. Only problem is the hole when the 2nd turbo starts pre-spooling, but I'm not sure how much you could tune that out. Only chance of doing it properly would be to run two boost controllers, but that gets pretty expensive if you are looking at EBC's and would be quite complicated to setup nicely I'd imagine.

[LJZ]

2 boost controlers hey... hrmmmm...
maybe 2 bleeder valves tuned right?? but then I would have to choose a pressure and stick with it.
From what I understand the true TT mode would get rid of that quick acceleration at lower rev's woudn't it? Leaving a higher power up around the high rev range.
Another thought I had to safeguard the turbos spiking would be to get a larger wastegate. Would this work in allowing all excess gas escape before before a boost spike or is it un-avoidable when opening up the exaust to 3".
If so how big should the wastegate be, 50, 60mm??

[ma61turbo]

LJZ, on 08 March 2011 - 09:49 AM, said:

2 boost controlers hey... hrmmmm...
maybe 2 bleeder valves tuned right?? but then I would have to choose a pressure and stick with it.
From what I understand the true TT mode would get rid of that quick acceleration at lower rev's woudn't it? Leaving a higher power up around the high rev range.
Another thought I had to safeguard the turbos spiking would be to get a larger wastegate. Would this work in allowing all excess gas escape before before a boost spike or is it un-avoidable when opening up the exaust to 3".
If so how big should the wastegate be, 50, 60mm??

Exactly, bit more mucking around to tune with bleed vlaves though and bleed valves are really great at giving boost spikes. IMO it doesn't really need a boost controller. Put the money saved towards more mods, you'll get a better benefit from it.

It does indeed. In fact, IMO, it's rubbish. I ran true twin mode for a while when I was having turbo issues(to reduce strain on #1 as it was on it's way out), and even with exhaust and VVTi it was horribly laggy. Didn't get real power until over 4k rpm. It was all the cons of a big single turbo without any of the benefits.

How you going to fit a larger wastegate? You can't just install one and expect it to work. There is a way of installing an external wastegate with the twins, but you have to remove all the sequential hardware to do it. IMO the benefits of doing this just aren't there, bit of a WOFTAM.

[LJZ]

Looks like you’re saving me a bunch of money mate haha.
As for the external wastegate I don’t properly understand how the supra's whole sequ. System works, thought it could be done but if you think not worth it I won’t bother. U seem to know a lot more about it than me.

Well after all this discussion this is what I am thinking of doing.

1.
Go to my local exhaust guy and design a custom 3" downpipe/midpipe with a 3" highflow cat (do I need to have flexi pipe on the downpipe section like a lot of the ones you can buy??)

2.
Replacing stock sparkplugs with some NGK BKR7E (6097), these were the most recommended for BPU upgrades with a gap of .7mm to avoid any misfires.

3.
Fit an air/fuel gauge (want to keep a close eye so I don’t end up running too lean)

This is where I will need to make some more decisions about what I want to do next, all of the following will need to be done at the same time as a tune on the dyno.


Either
Manual Boost controller
Electronic Boost controller
Whether I need to fit a BCC or not

Bigger fuel pump?? (Will have to talk to the tuner once it’s on the dyno, I’m pretty sure that the stock fuel system will be fine but would like to have it all checked just to make sure)

Later down the track I will most defiantly get the turbo's high flowed. I shall have another thread for that im sure.

[ben12a]

I think you have come to the point a lot of the 1J/2J guys get to. Ahead on the road isn't so much a fork as a T junction. You either leave the turbos and management alone (maybe some signal benders etc) OR you go all out and build a defect magnet. Unlike Nissan where there are a million shades of grey it gets pretty black and white with the good toyota stuff.

You really need to ask yourself: why am I modifying? Is it because there is something you don't quite like, or more because you just like modifying. I have done both, spent lots, and had a great time with various street cars. The race car has stock motor, stock turbos, stock management, and stock fuel system. Go figure.

[LJZ]

ahh Ben you are full of wisdome. Indeed it is one hell of a T junction that I am just about loosing sleep over.
Damn datsun drivers and all their grey cheekyness.

After reading your post got me thinking and im not really too sure why its a never ending saga to modify my car in every way, I think it is simply that I just love to modify :lol:
For my supra I want to keep it on the street, this is the main thing. I never want to make it so that I am always avoiding the 5.0 and only taking it out on midnight runs.
I want to enjoy it as much as possible and have a air amount of power at my disposal just for kicks really.
Who knows where it will end, I think its going to be an ongoing thing trying to do more sneaky mods and keep it a sleeper. for example stretching the stock TT system to its limits to keep it looking stock as, bigger fuel pump, injectors, ECU eventually. All things which will not be seen.

For now thought im just going to tackle the exaust problem then we shal see.
After some looking around on the net I found a company which make highflow cats which i REALY like!! ever heard of them http://www.venomexhaustworks.com.au/
I want to get their 3" 100CPSI highflow cat with 5" body

[ma61turbo]

LJZ, on 08 March 2011 - 03:27 PM, said:

Looks like you’re saving me a bunch of money mate haha.
As for the external wastegate I don’t properly understand how the supra's whole sequ. System works, thought it could be done but if you think not worth it I won’t bother. U seem to know a lot more about it than me.

http://www.max-boost...supra/turbo.htm

This covers the operation of the system, very handy.

Quote

Well after all this discussion this is what I am thinking of doing.

1. Go to my local exhaust guy and design a custom 3" downpipe/midpipe with a 3" highflow cat (do I need to have flexi pipe on the downpipe section like a lot of the ones you can buy??)

If you are going for a custom system, get a 2.5" dump/mid made and then 3" cat-back if you want. Unlikely you'll need a flexi-joint, I've never run one in my cars and never had any issues. Don't forget the exhaust hangers are generally rubber and allow movement anyway.

Quote

2. Replacing stock sparkplugs with some NGK BKR7E (6097), these were the most recommended for BPU upgrades with a gap of .7mm to avoid any misfires.

Unless you are pushing really high hp 0.7mm I think will probably be too small. I wouldn't expect you need to go closer than 0.8mm, pretty sure the BKR7E are set to 0.8 out of the box also(I have a set in mine). No issues with approx 230rwkw.

Quote

3. Fit an air/fuel gauge (want to keep a close eye so I don’t end up running too lean)

IMO waste of money. You'll never be able to push the stock twins hard enough to have issues running lean with the stock fuel pump. Only useful guages are wideband anyway and these are pretty expensive still I think.

Quote

This is where I will need to make some more decisions about what I want to do next, all of the following will need to be done at the same time as a tune on the dyno.


Either
Manual Boost controller
Electronic Boost controller
Whether I need to fit a BCC or not

Bigger fuel pump?? (Will have to talk to the tuner once it’s on the dyno, I’m pretty sure that the stock fuel system will be fine but would like to have it all checked just to make sure)

Later down the track I will most defiantly get the turbo's high flowed. I shall have another thread for that im sure.

Just go the standard BPU route. Tried and tested by many, many people. It's only when you feel like squeezing out the last bit of useable power out of the stock twins that you'l have to start looking at doing something creative. You will need a BCC if you want to run much more than stock boost(my vvti still doesn't have one and no evidence of any cutout so far at 1bar). Forget fuel pump, stock one is fine for the max power the stock twins will put out.

Don't forget you're braking and suspension components as well! IMO these should be performed first before going all-out for power.

[ma61turbo]

ben12a, on 08 March 2011 - 08:47 PM, said:

I think you have come to the point a lot of the 1J/2J guys get to. Ahead on the road isn't so much a fork as a T junction. You either leave the turbos and management alone (maybe some signal benders etc) OR you go all out and build a defect magnet. Unlike Nissan where there are a million shades of grey it gets pretty black and white with the good toyota stuff.

You really need to ask yourself: why am I modifying? Is it because there is something you don't quite like, or more because you just like modifying. I have done both, spent lots, and had a great time with various street cars. The race car has stock motor, stock turbos, stock management, and stock fuel system. Go figure.

Not sure he's anywhere near there yet! Standard BPU mods will net in the region of 270rwkw, once you want to go for 300+rwkw then you need to decide what you want to do.

LJZ: FWIW ignore the guys over on the national forums that believe 300rwkw is posible with stock turbos, it ain't going to happen(regardless of what x dyno run tells you).