well of course there is "static" turbo options out there, anything from gt17,18, 20 would do the job, its just getting something that is a easy fit. Things to look at is the exhaust manifold connection, oil feed and drain connections, and of course downpipe and intake connections. Orientation will also need to be sort of close, obviuosly housings can be rotated but with the exhaust housing the wastegate is connected so need to be looked at.
I still think readings are needed just to make the theory is correct, the pressures might be not that bad, and it could be something else causing it.
I still think that relieving the presure is the way forward, its just knowing wat is acceptable and safe. There should be enough emp there to create boost, so i wouldnt worry about boost and lag, theres always going to more pressure at the manifold than at the turbo during spool, so you shouldnt see any effect.

i believe the company matt was using for the stage 3 was turbo dynamics, but costs will be quite big for them to develope a turbo, or do any kind of fow benching, which i think put matt off in the end.

Its a tough decision, but i would stick with it and get some readings and go from there. I would try and find some information on what emp is aceptable.

 

Thanks Mad - I am not planning on going one route over the other just yet, but i want to work out what all the options are.

the costs invovled for doing either option and things along those lines.

I would hate to be in a situation where we get some EMP readings make the decision to go down the bypass route rather than getting a larger turbo, then find we hit a whole other host of issues around the control side of the bypass system that we have overlooked....

As you say a tough decision, but one i wish to try to make with as much ammo\information to help me make the 'right' decision....

I have just emailed the turbocentre to ask if they know of another off the shelf unit that has the same flow characteristics and lag etc etc as the stage 2.

If there is one that is there, and it can be made to fit relatively easily then i think i would be more inclined to go down that route - Assuming it is EMP at fault and not head design...

Let some-one else use the stage 2 for a low boost low tune scenaro to just flatten out the torque curve comparied to a normal unit

 

well the only thing i would say is that if you plan to change to a larger turbo, you will start to have lag issues, anything larger than a gt17 static vane it will be a tad laggy and less responsive. At this stage vnt would be my only thoughts.

Like i said in the other thread a external wastegate or blow off valve does not need to dump to the exhuast, it can dump to the atmosphere. You could do this for testing if needed, and then think about relocating to the exhuast.

 

yeah, i know for testing we can go about dumping it to atmosphere.. still however need to work out where to route the pipe to where it is not going to be dumping hot gases on anything critical.. or knocking etc etc...

the 'stage 3' was going to be using the GT17 exhaust housing from my conversations with Matt so that was the sort of size i was expecting to go up to only - for a static system...

VNT would be the best bet you are right, but i just dont have the time for the development work needed to perfect the system. It has to work 'out the box' as i use my car day to day for work... turning up in a 206 with more dents than straight panels is not such a good look :lol:

On an unrealted note... electronic boost controllers what names are good and what should be avoided - i guess anything from china....

checking out fleabay suggests there are a number of different options for around the £100 mark... and then there are some much higher prices around the £300 range for brand names...

 

if anybody wants to actually do any experimenting with all these theories, I modified a light dimmer pcb and put in my own controller with its own firmware for duty cycle control at the correct frequency if anyone wants to borrow it.

Very small, and easy to use - three inputs, 12v, -ve, and switched -ve (for the solenoid control). i.e you control the egr solenoid to permanent +ve and connect the negative to the switched negative.

If that makes sense, then you can open and shut the egr by twisting a dial.

I did some 'cigarette packet' estimation, and I tihnk the best way of controlling the egr would be proportional response based on boost/emp imbalance, with limiters. Just my two cents though.

Anyway as a starting point i'd settle for knowing what emps currently are. Proof of the theory would give me enough reason to kickstart the development of a system to help solve it.

As for the turbo,I could give a few suggestions but i'm reluctant. Anything moderately bigger than the stock turbo is going to take a lag hit and until I see dan's running i'm not sure what scale it's gunna be.

 

As for the turbo,I could give a few suggestions but i'm reluctant. Anything moderately bigger than the stock turbo is going to take a lag hit and until I see dan's running i'm not sure what scale it's gunna be.

Speaking to Matt, he didn't think lag would be too much of an issue with a bit of work on the mapping side.

I can't see it being considerably worse than the stage 2, as from what I've heard that is noticeable worse than standard.

If I was taking the streetwise any further, I'd defo be going down the TDS route :broon:

 

I know what you're saying, and I totally agree. I know the difference between a stock map and a remap with both the stage one and my vnt, and there is a world of difference when there's a bit of extra fuel in, make no mistake, it is magic the impact you can have....


but................the tds turbo, is as far as I'm aware anyway, a generation older (can't remember if it's a garrett or mitsubishi now). That probably means it uses different materials, different fin profiles, it'l be missing whatever they've updated since really. It won't be efficient as a turbo of the same size today.

That might sound like i'm nitpicking....I'm not trying to, but it's worth mentioning as, for example, now there's the GTB range of vnt's out now, and if i'd got one of them instead with more or less the same dimensions (GTB2260 actually), i'd be looking at much better boost response than my own, slightly smaller gt2256, yet still push enough air for 280-310hp.

It uses the same bmw flanges as far as i'm aware though, so might upgrade yet LOL

(I'l make this one work first).

 

I know what you are saying there Dakta, but if you dont want to say over the open forum you mind sending me a pm?

I just want to see what is out there and what the options are from some-one that has already done a bit of the leg work re-size and the various compressor maps etc...

Spent a bit of time doing some research today and think i finally half understand the bloody graphs :lol:

I have to say thought in fairness the stage 2 spools a lot later than OE, and i have driven with a car that did not hit peak toruq until 2750rpm - so i know what lag is acceptable for day to day and what it is a bit too far....

Dont think i will ever need anything that can flow enough for 300bhp tho

 

There's absolutely nothing I won't say over an open forum, I just don't wany to say 'turbo xyz will be drivable with minimal lag' and later find out your definition of lag is my definition of threshold

Personally I'm quite optimistic about Dan's tds conversion, and I am hoping he pushes the boundaries a little more than he's let on, in order to reveal the turbos capabilities even if that isn't his direct aims.

I'm particularly interested in that unit because it shares common flanges with quite a range turbos. For example it's interchangable with my vnt turbocharger, if my vnt went to pot I can swap it to either garrett or mitsubishi turbo from the bmw 2.5 TDS range without changing adapter nor downpipe (or even the oil feeds), and vice versa, this is the same for the VNT range, whilst most vnt's are like wastegated turbos and have a range of flanges, I find a lot of the bmw turbos once again share that common flange arrangement, and if for some absolutely crazy reason I fancied an upgrade to a GTB2260v for a better bottom and and a legitimate push towards 300hp, it could be arranged with a simple turbo swap.

I took a big risk with my turbo, I wasn't ever expecting to spool it, I needed a turbo that was easy to fit and cheap and the gt2256v turned up. I was amazed to see it spool at reasonable revs, (expecting post 2500+) and it was more 1500. I don't think wastegated turbos will yield the same surprises.

Anyway basically, none of thats really relevant to you I guess but until I know how the wastegated turbos in that range perform i'd be a little reluctant to guide people to definite turbo models. I will try and offer some guidance though. You don't have to take it, or set much store by it but if helps then great.

----

Right, there is a long mathematic process for working out what compressor wheel etc you need. Unless you want to go through that pain (and it is quite nasty, been there) then the first thing i'd do is lookup on essexturbos or some other turbo workshop website, what sort of turbo vehicles with your desired power output are running, and take note of their engine size, try and keep it similar to yours. It is likely the turbos were selected for reasonable low end performance with the given power, so providing the engine capacity and rev range is similar you won't be a million miles off.

Secondly, regarding the popular garrett series turbos ,more of a warning than a tip - turbo numbers don't always tell you what the turbo is. GT1549 is a garrett turbo with a turbine from the gt15 family, and a compressor wheel with a 49mm exducer. (the big side).

A GT1749 would also have a compressor wheel with a 49mm exducer (inducer may vary), but would have an exhaust wheel from the GT17 family. typically (not always), the higher the 'GTxx' number, the bigger the exhaust side, and in a wastegated environment this will always lead to a higher boost threshold + more lag. A/R ratios also contribute to lag as they alter the flow dynamics of a turbo exhaust/intake housing, generally the more it can flow the more lethargic it will feel, the less it flows, the more emp will be created. (This is what I think might be limiting the stage 2, I don't beleive the wheels themselves are badly sized).

It's also worth noting that the existence VNT's are actually in themselves quite good proof of the emp theory, because they got rid of the wastegate completely, and operate ONLY by adjusting the effective a/r ratio of the turbo. By doing this you alter the emp, and it is this creation of emp that gives it such a good spool. This is also why it is vital to have good vane control, because it is easy to emulate the stage2 problem if boost is not managed. VNT's are almost always specced so the engine they are fitted to cannot outflow the turbo (i.e create boost) with the vanes open, they are designed to flow too much to allow this to happen (otherwise you'd have uncontrolled boost). In essence vnt turbos do not 'pretend to be big turbos'. They are big turbos with the ability to pretend to be small.

You can also operate a VNT with an external wastegate, and fix the vanes in a position that gives you the most desirable drive. This obviously doesn't give you the benefits of a well-controlled vnt mechanism as you can't set it for too little lag without causing emp at the top end, and vice versa, but in essence it will work.

I have not come across a wastegated gt17 yet, however that'd be my starting point for research, failing that I would look at the possibility of GT20's, in particular the GT2052 (some of these are almost impossible to make fit, however different configs might exist). However as a wastegated turbo it's very likely you'l see an increase in the turbo threshold, whether or not this is tolerable comes down to the driver i'm afraid.

Also don't focus on the compressor wheel too much, the 49mm part on the standard zr turbo is used on 170bhp applications. A bigger wheel will help increase efficiency and reduce requried rotational speed for a given turbine and boost pressure, but you don't have to go too massive. 56mm for example would be pointless on a GT15. A lot of people put them on gt17 vnt's with decent circa 200hp results though. Personally I'd sooner have a Gt20 turbine for any serious compressor upgrades.

I wouldn't go too big though if you can, and obviously forget most petrol turbos like the t25, they are not well suited at all.

Hope that gives a breif insider anyway. By all means PM me if i've just confused you further - the long and short of it though is it will always remain a compromise between drivability and power, with vnt a way of stretching out a bit of performance at either end of the scale.

 

GTB2260VK is my new turbo, only £600 + cost of manifold!

 

Thanks a good starting point indeed - and what i had already been looking at in terms of sizes and units...

I had noticed that the BMW\Freelander unts were on quite a few applications, also with the same flanges etc, so was being swayed along those lines - the challenge will be to find one cheap enough to make it cost effective in the timeframes i am after really...

I could continue to pootle round using elss than 50% throttle for quite a long time i am sure, but it is so dammed tempting to just 'get on with it' all the time :lol:

Like you say there is that compromise there, about what makes summit driveable and what makes nice big top end figures.. i am really happy with car at the level of tune it is, so unless i get my 'non wingy's sorted and amted up to a large VNT, i am ideally after something close to the stage 2 in all means.

Knowing the luck i have had with a few things i will be right inbetween turbo sizes and have to make a choice.... or the one that would work perfectly is like rocking horse poo or summit....

I agree that VNT is the way i should be looking but it seems to me like there are still a few too many issues with that scenario.... I'll give matt an email and see how long he thinks he could get the EGR mapping side sorted out as that might sway me that way too....

So many options and decisions to make.....

 

• A Turbo that has the same or similar spool characteristics as a stage 2 unit - EG has hit max boost by about 2500rpm, but with a larger exhuast housing

Without going VNT you are going to struggle to get OEM spool with better flow as I've found. I originally started out looking for the GT2052 for my van but the one I got really wouldn't fit easily, so I went shopping again and ended up with the one I have now. As said above it is fairly old skool and I think will be fairly laggy, but compared to the T2 in my old prima I think it'll be tolerable and a lot more power to be had.

Don't give up on the external wastegate option yet though as the pipe can either be muffled and dumped under the car or it could be spliced back into either the downpipe or maybe more conveniently the Decat.

 

Not giving up yet, but thanks for your input ETV... i guessed it was not going to be as easy as find the next family up and bolt it on, as otherwise people would have thought of it before now....

I am not sure there will be enough space to splice it into the decat that easily, depending on the diameter of the pipework used and the route taken, joining it to downpipe will be the easiest option as it is right there... but not hugely convinient.

 

im struggling to find any compressor maps for the GT17 and GT18, most websites only list the GT15 range then next are the GT20/Gt22's. i know they do exist in wastegate form as the Saab 9-3 uses the GT1752.

what RPM is full boost going to start with a bigger WG turbo that will flow 160bhp top end?

 

That'll depend on the turbo sizing. There are big and small versions of most turbos and the exhaust turbine housing also has a vital part to play.

 

cheap compared to the hybrids that!

I also struggled to find any info on anything in the GT 17 family - from what i can work out a lot of them share the same exhuast housing as the GT15 family...

I got in touch with wilky on RT as he is a custom turbo builder, and he had no obvious suggestions to try - other than going VNT.

 

my gt2256v cost £200...

 

Mine cost 100 lol. 600 seems abit steep but def cheaper than hybrid.

 

Don't forget the manifold, I've seen his pleas for assistance on t'club!

:dddc:

However, if you can....GTB2260v is the way to go. I want one myself.

But i'ms stuck with what ive got for now.
.

 

Cheaper if you can get it to fit and work!

A custom manifold won't be cheap. £200 at the very least.

 

GT20 at least size but add a supercharger for the turbo lag and jobs a good un, add a extra like NOZ or LPG.

 

Or you could just fit vnt.

The result is the problem of vane control, but it's 'the' problem to solve!

You know, out of all the problems I could be facing, i'm so glad it boils down to a simple case of 'move the actuator if boost gets too much'.

You know, boost control didn't work too well, but it's still a fairly simple problem. No need for complicated solutions, nitrous, superchargers etc

 

i came across this turbo any wondered if it'll be suitable?

its the kkk-K03/04 hybrid:
http://img406.imageshack.us/img406/7941/a3turbodj1.jpg
http://www.stealthtdi.com/ST-Turbos.jpg

its used as an upgrade on the wastegated 1996-1997 Passat and 1997-1999 Jetta 1.9TDis to hit ~165bhp
http://www.kermatdi.com/servlet/-strse-428/-dsh-K03-fdsh-K04-Hybrid-turbo-for/Detail?category=-Performance+Parts%3ATurbos

 

you been digging around on tdiclub by anychance?

 

ive been searching online everyday lol, ive found some mad mechanical methods of controlling VNTs by linking to the throttle cable and having an actuator and all sorts but every method isnt as good as a factory fitted VNT system.

the old passatts/jettas have a garrett GT15 as stock, or a K03 and people are taking them from the stock 90hp to 165-175hp!

 

i took mine to 170 on the hybrid so i guess it will be similar to that...

If it EMP killing the car and not a stat or some-other odd gremlin, we should see a little more bhp out of it when the backpressure is reduced...

 

i see from a previous thread that a GT2052 could possibly be a decent upgrade, but how about having a hybrid created using that but with a GT17 hot side?