Bigger Waste gate for BPU so the turbos can cope with higher boost??

[Scott]

Boost controller? Yeah, if I was staying bpu I'd like to have that element of control, but it goes hand in hand with the J-specs, you may lose slight top end but you would gain low down torque due to the back pressure from having a restrictor ring fitted

 

Ah yes, i always have boost controller in my head and yet write down boost gauge. Most of the time i catch it before hitting reply.. thanks

 

if i was doing it all from scratch i would have..

 

1st cat back exhaust system fitted with the 1st de-cat pipe for restrictor ring purposes.

 

AEM Stand alone (future proof and great for TTC) with added boost controller (i assume it has one)

 

Either Stock air box with TRD filter or a shielded induction kit

 

Of course all the usual bits and bobs... Walbro fuel pump, O2 sensor, full service, colder spark plugs etc.

[Guest FKADizzmystar]

you cant use the stock O2 sensor?

[Scott]

you cant use the stock O2 sensor?

 

Yes but there is a VERY good chance that it would be fubarred. You just replace the one thats on there with a new one, stock one does the job nicely.

 

You will know if its fooked when your MPG is less than 20 (when driving normally) and your exhaust spits out flames constantly (overfueling vs Hot manifold and no CAT's to take it)

[Guest FKADizzmystar]

awsome, what do they charge these days for a new O2 Sensor

[Nic]

so the perfect set up would be:

 

getting rid of the stock down pipe with the two cats on it and putting a straight through down pipe on then,

getting a high flow cat.

and then the cat back part.

 

all 3" to a 4" cannon

 

??

 

The first bit is a bit wrong.

 

1. Fit a de-cat pipe to replace the first cat

2. Fit a high flow second cat.

3. Fit a 3" cat back exhaust

 

Here is a pic of the cats, the small one on the right is the 1st cat nearest the turbo, the second on the left runs underneath the front of the car.

 

[tucky40]

Also you CANT reduce boost with a boost controller........... a boost controller adds duty and allows you to INCREASE boost.

 

This is important as your turbos will over boost without a restrictor ring or some kind of restriction in the exhaust system.

[Guest FKADizzmystar]

so if you chuck a bleed valve in and you have put all the exhaust and RR on, say your at 14 PSI and u turn it up to 17PSI , you cant turn it back down to 14PSI

[bolarbag]

Also you CANT reduce boost with a boost controller........... a boost controller adds duty and allows you to INCREASE boost.

 

This is important as your turbos will over boost without a restrictor ring or some kind of restriction in the exhaust system.

 

What tucky is saying here is you cant reduce it from the stock specified boost, in an ideal world the boost controller would able you to specify which boost you would like and off we go

 

In the j-specs as there is a flaw in the stock wastegate system, if you specify a set boost, its only gonna delay the inevitible and overboost if you dont fit a restrictor ring,

 

You could set the boost controller to 2bar, meaning it should hold the wg spring shut til we reach 2bar, but it wont as the spring isnt strong enough and it will open around the 1.1bar mark, conversely, if you set the bc to 1bar on a j-spec w/o a restrictor ring it will keep the wg spring shut until 1bar, then open, you would expect the car to stay at 1bar but it doesnt as the wastegate openings arent big enough and some of the gases that are meant to go through the wg port end up travelling to the turbine, creating higher boost

 

So in essence a BC is not worth it on a j-spec as you dont really have control of your boost, we rely on a mechanical inefficiency, fit a restrictor ring to prevent this overboosting and dont worry about it until you decided to go the hybrid or single route

[Guest FKADizzmystar]

what about an electronic Boost Controller?

i remeber having an SR20 turbo Nissan 180sx and fitted it with a Non electronic boost gauge and i could turn it up or down

[bolarbag]

I have been talking about an electronic boost controller all along, both mechanical and ebc do the same thing, one is mechanical the other solenoid driven,

 

As I said in an ideal world you would be able to put your boost up and down, but for the j-spec tt, you cant as the defining factor is our wastegate setup, obviously the SR20 had a better(or more expansive) internal wg setup than the 2jz-gte turbos, but that doesnt mean the turbos are crap, it just means they are not meant to run at 1.2+bar properly

 

Obviously they can though, and you will have guys who have ridden tens of thousands of miles with no problems

[Guest FKADizzmystar]

so once i get my bpu setup and turn the boost to 17PSI/1.2 thats its foreva lol

[Nic]

so once i get my bpu setup and turn the boost to 17PSI/1.2 thats its foreva lol

 

Anything above that and the turbos are out of their efficiency range, you'll just develop more heat and no more power.

[Guest FKADizzmystar]

kewl, well from what i hear 17psi is not to bad so all is good

[Guest FKADizzmystar]

SO in summery, once i do BPU and the turbos spool past 17psi and up to 23 or so, without the restrictor rings, to turn them down just obviously add a RR to 17psi and that's it. so yeah no boost Controller needed

Edited May 14, 2008 by FKADizzmystar (see edit history)

[tDR]

turbo back, the cat back does nothing but create noise, if your stock exhaust is in good condition you could add your two decats and have similar performance, without the noise

 

That's wrong - decats on a stock exhaust sees little to no gain. The stock exhaust is just far too restrictive - have you had a look at the pipework?

 

You also don't gain torque with a restrictor ring fitted vs. not having one. That's NA thinking. With a turbocharged car you want no backpressure - it's the enemy. So as free flowing an exhaust system as possible, with the caveat of limiting the boost because of the JDM wastegate issue. Think about it - Just having the turbo in the exhaust system is already a big blockage over an NA.

[tDR]

so why do people go out and buy these Boost Controllers when once you turn the to 17psi there useless

 

I've always maintained there's not a lot of point in an EBC on a JDM car. If anything, you could theoretically produce a quicker turbo spool with one.

[tomgeer]

What would happen if you knackered the turbos by overboosting?, would it be just the turbos you destroyed or other components too?

[tDR]

Depends on the failure - there is a chance of debris being ingested by the engine leading to a full stripdown and rebuild being required.

[tomgeer]

Bl**dy hell

[carl0s]

I've always maintained there's not a lot of point in an EBC on a JDM car. If anything, you could theoretically produce a quicker turbo spool with one.

 

Do you mean without one?

 

I think I disagree though. I have no EBC on my car, and for this reason the car doesn't see above 14psi until high revs in top-ish gear.

 

You have to set the upper boost limit with your restrictor ring/exhaust system. This is the absolute max the car can make and you need to make sure the car doesn't go above that.

Unfortunately this max boost is always going to be in high gear, which will leave you with less boost in lower gears.

An EBC would allow the wastegate to be blocked off in those lower gears to attain closer to your target boost (say 17-18psi) in all gears.

 

Wouldn't it?

 

It's on my list of things to do. If it makes no difference I'll come and tell you all

[tDR]

Do you mean without one?

 

 

No, as per my post, I mean with one

 

You can play about with the gain and set gain on EBC's to promote quick spool. Depending on the EBC, you can also set a target boost level that it will always try to achieve independent of what gear you're in, or 'train' it to know what gear you're in and apply different duty cycle settings on the solenoid to make your target boost in every gear.

 

Because our cars already produce a lot of torque throughout the rev range, there isn't any real gain to be had as you run into traction 'issues' in lower gears. I will be playing about with the EBC functionality of my MAP2 on the strip this year though just to see if gains can be had through quicker spool.

 

Cheers,

 

Brian.

[carl0s]

No, as per my post, I mean with one

 

You can play about with the gain and set gain on EBC's to promote quick spool. Depending on the EBC, you can also set a target boost level that it will always try to achieve independent of what gear you're in, or 'train' it to know what gear you're in and apply different duty cycle settings on the solenoid to make your target boost in every gear.

 

Because our cars already produce a lot of torque throughout the rev range, there isn't any real gain to be had as you run into traction 'issues' in lower gears. I will be playing about with the EBC functionality of my MAP2 on the strip this year though just to see if gains can be had through quicker spool.

 

Cheers,

 

Brian.

 

Ah I see, so you're saying what I was thinking then? It's just the way you said 'not much point' had me confused a bit

[tDR]

Yes, I was giving my opinion that there isn't much point on a JDM car but also offering the potential argument for having one (EBC).

[carl0s]

Yes, I was giving my opinion that there isn't much point on a JDM car but also offering the potential argument for having one (EBC).

 

Gotcha

[bolarbag]

That's wrong - decats on a stock exhaust sees little to no gain. The stock exhaust is just far too restrictive - have you had a look at the pipework?

 

You also don't gain torque with a restrictor ring fitted vs. not having one. That's NA thinking. With a turbocharged car you want no backpressure - it's the enemy. So as free flowing an exhaust system as possible, with the caveat of limiting the boost because of the JDM wastegate issue. Think about it - Just having the turbo in the exhaust system is already a big blockage over an NA.

 

I've only seen the stock exhaust a few times, I did wonder about the diameter of the stock piping, and the routing is a little suspect

 

Yeah you wont gain torque, its easy to lapse into the old wifes tales of thinking:innocent:, you will have a slight increase in spool though as your egt's will be higher, which may give you an increase in torque as your ecu tries to compensate, but then the stock ecu always runs overly rich anyhow, so its probably zapping power

 

Playing about with the PID on an ebc on a j-spec would have no noticeable gains(no pun intended:innocent:) to the driver, on UK turbos or a Single/Big Twins it would be a totally different ball game, but even on the UK's it would still be minimal