Right, the time will soon upon us when Rufus is removed from mothballs and put back on the road (intending early spring next year) and there's one or two things I wanted to sort.

Main thing is wanting to overcome the compressor surge I get when under heavy load, low rpm in top gear, and sometimes in fourth aswell. It looks to be down to the TD06 being a bit too big for the 2 litre engine. Couple this with full 3" exhaust, straight intake and opened up head, there's not much resistance to it throwing in all it's got.

My first thought was to go for a 2.2 stroker kit, increasing engine size by 10% would certainly help as it would be able to consume the turbos output more easily. But, given the buying of the kit, fitting it, subsequent mapping runs and a recession on, I've decided that's going to be a bit too expensive. Also considered a different turbo but again we're looking at purchase, fitting with probable new downpipe and wastegate issues etc. so that's not really an option either.

So, we're left with seeing what can be done with the TD06. I'm considering getting it off and sent to a specialist to have a look at, so gauging people's ideas and theories on what can be done. Presumably some sort of clipping can be done to the fins, on one side or other, to reduce the 'poke' a little, I'm guessing on the compressor side so it doesn't affect spool up so much.

One of the second problems in control of the boost, it has been a bit tricky getting it to 'come in' just right, it would easily want to spike quite nastily. Again I'm thinking that clipping will aid this as if it's not chucking in so much air it'll be a little easier to control the process.

Thoughts and opinions then guys

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

Hi

i also think that a TD06 is to big, a TD05 as mitsubishi uses on his 4G63 is better

please note: bigger is not better!

is is a game with flow-speed and volume

small port -> high flow-speed in the mid range, higher flow speed in high range but restrictiv -> + torque in mid range, - torque in high range
big port -> less flow speed in the mid rage, high flow speed in high range and not restrictiv - torque in mid range, + torque in the high range

i speak not only from the head, i speak from the complete package (engine, turbo, exhaust, etc.) that must balanced

do you know what i want to say

to your problem:
i have two ideas yet,

- ceramic portliners (not so easy and cheap)

- ceramic coated exhaust manifold (only inside if you use a stainless manifold)

porsche uses on his first single turbo engine ceramic portliners for better spool up
if you lose less heat, your turbo becomes more energy -> better spool up

greetz

_________________
KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

Indeed, wondering if a TD05 compressor side can be matches with the TD06 exhaust side?

I would prefer more midrange torque. The mods I have so far are reasonably balanced, and I think a stroked engine would finish that nicely, but the expense is not an option and it throws up the possibility of other issues so I'll be leaving that alone. Thus the turbo needs to be reduced in size/output to be better matched with the engine.

For info, spec of supporting mods is thus -
* Motec M4 Pro ecu with lambda control, also controlling boost levels with suitable safety features enabled.
* Wlabro intank 255 pump, Aeromotive adjustable FPR, Wolfkatz fuel rail, SARD 800cc injectors.
* Head work - ported, polished, 1mm oversized exhaust valves, Piper 264 degree 10.5mm lift cams, HKS adjustable pullies.
* Exhaust manifold - standard 9 stud 185 cast unit, port matched to head and opened out including removal of 'twin scroll' exit.
* TD06 20G turbo, TIAL 38mm external wastegate on recirc.
* 3" exhaust, lagged from turbo to flexi section.
* Blitz sus filter in cold air box with direct feed from bumper, through straight intake to turbo.
* TVIS disabled.

All that has removed quite a bit of restriction, so the turbo is free to fly, think that's half the problem

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

Hi,

the problem you have is not the restriction,

it sounds that your problem is that you have no air flow-speed (->volume) in the mid range, cause: to big turbo, bigger valves, ported manifolds & head -> bad filling of the combustion chambers in the mid range
looks like that your engine is designed for high boost & rpm

a stroker kit could be a good answer, another cheap ideas ->

- you write that you exhaust ist lagged, remove it to get a bigger themp. difference from ex.manifold to downpipe
- you can map your ECU new
- play with the cam timing

does i ask you what compression ration you drive and why do you removed the twin scroll exit?

greetz

_________________
KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

Not 100% sure what the compression ratio is to be honest, but following the headwork with it skimmed and the block decked it was refitted with a TTE 1.6mm head gasket, so compression is likely lower than standard by a little.

The exhaust manifold was bored out to a single exit as the wastegate comes off a sandwich plate affixed between the manifold and turbo with a single exit plonked bang in the middle of the rear of the plate - keeping the twin exit on the manifold would inhibit the ability of the wastegate to work properly, but now it can divert more easily away from the turbo when required.

Each of the modifications on their own wouldn't be too much of a problem, but all together they do lead to reduced air speed through the engine - despite standard chargecooler and inlet manifold, albeit with the TVIS butterflies opened.

Another thought might be to re-introduce the TVIS and have the Motec control that, would certainly help with torque lower down I suspect. That said, cams can be adjusted also with some advance on the ignition cam, then the rest of the mapping in higher rpm ranges can be knocked off a bit as required.

That wouldn't solve the compressor surge though I suspect, so we'd still need to reduce the effectiveness of the compressor

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

NEVER consider to clip an exhaust wheel, it's the worst thing you could do.
To solve your surge problems you could:
If possible, anti-surge port your compressor cover;
Or map your boost controller vs rpm AND gear.

_________________
Wolf_Tm
TM 250 enduro 2 stroke
GT-four ST205 Snowy White with selfmade 3SGTE v4.1 - [2.34kg/bhp DynoDynamics]
http://www.youtube.com/WolfTm250
http://www.facebook.com/wolf.tm

The Motec is mapped with boost in each gear and we've had to drop it down to 1 bar in 5th in the lower rpm range to get over the worst of it, but it's not making it any more drivable.

Also sought advice from Adrian at Fesnsport who also suggested anti-surge compressor housing, so I think that may well be the way forward, and if it could be matched with a TD05 compressor aswell it should do the trick.

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

Ok for the anti-surge porting...
but, anyway, it's really strange that mapping boost vs rpm AND gear is giving you "driving problems":
in fact ALSO the anti-surge porting will give you the same, that is to say less boost in a known rpm region...

Hope you could port the TD05 comp then!

_________________
Wolf_Tm
TM 250 enduro 2 stroke
GT-four ST205 Snowy White with selfmade 3SGTE v4.1 - [2.34kg/bhp DynoDynamics]
http://www.youtube.com/WolfTm250
http://www.facebook.com/wolf.tm

does it surge if left to actuator boost only?

If so then it can be mapped out with the motec. If not an anti-surge housong may cure it but there's no actual guarantee as it only moves the surge line so far....

Spoken to Matt at Turbodynamics and we've come up with the following solution. The compressor itself cannot be downsized as such, so we're sicking with the basic 20G compressor on it. On that we're going to sort an anti-surge shroud which should hopefully get rid of the surge problems. We're also going to convert it to ball bearing cartridge as opposed to it's current out dated 270 degree thrust bearing.

The hope is that this will remove the surge issue and spin it up sooner in the rev range so it's a bit more 'useful' in ordinary driving conditions. Also going to try upping the boost a touch to around 1.4 bar, all of which should make it more controlable and more 'drivable' on the road, which is my aim.

I can't recall if it surged on the actuator on it's own, and it was only a minor but annoying situation when in top gear under heavy load at low rpm between 2 - 4.5 or so. I only recall it once in fourth gear when I was clearly in too high a gear. Hoping that as it's not overly severe the shroud should be enough to do the trick.

The rest should be able to be mapped out by Adrian. Aim has been revised to around 350/60bhp and similar torque in a nice road set-up. I'm keeping the chargecooler, upgraded of course with lagging and an uprated pre-rad so overall beter capacity, which should be able to cope with the 1.4 bar limit every nowe and again.

Fingers crossed anyway!

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

Hi,

pretty nice solution
i have no experience with it, but think about coating the manifold, ex.housing and the downpipe
i was the last few days in contact with
http://www.zircotec.com/

you think about to uprate the front radiator of the intercooler system?
i also plan the same step, but the only item i know is the TTE group A spec -> ~1700€
do you know a company who build a p&p uprated radiator?

greetz

_________________
KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

Mook,
How much is that conversion going to cost? IMHO be carefull in throwing good money after bad. (sorry to be so blunt - I am an engineer so in my book there is a right way and a wrong way to do something).

Having run through compressor calcs for the TD06-20G :- http://gt4dc.co.uk/forum/viewtopic.php? ... urbo+calcs

IMHO it is old technology. Compare it to a similar sized (but slightly bigger GT3071R) - you can see that the TD06-20G doesn't want to produce 1.4 bar until 4500rpm - the Gt3071R will get there at 3500rpm.

IMHO anti-surge housings are a botch/work around that basically allow a percentage of the pressurised air to recirculate to the inlet side of the compressor wheel. The downside of this is that it makes the turbo spool slower as it essentially has a small air leak from outlet to inlet and is likely to also move the boost threshold higher in the rev range. If you have to have a particular (large) turbo to reach your BHP goal/be competitive in a race/drag situation then I can see it has a place (in such circumstances you are not in the low end of the rev range and it only really helps on odd circuits or when a driver gets the wrong gear!)

For a road application it either means your turbo is too big or is a poor match to the engine airflow requirements.

Adding a ball bearing cartridge IMHO will do nothing to help you but try to overcome some of the lag you have created by adding the anti-surge housing. (yes the 270 deg bearing is pants and I would say not suitable for prolonged high boost application - so I can see its benefits of sorts).

Just be carefull that you don't end up spanking a load of cash based on TD's suggestions.

If you goal is 340bhp and 340 lb/ft at 1.4 bar you really don't need anything as big as a TD06-20G anyway. A good hybrid CT26 (read owens 48mm trim and std exhaust housing casting or a lovely turbo technics single port turbine housing) or a Garrett ball bearing will do the job properly.

IMHO I would probably sacrifice 10bhp and go for a Garrett GT28RS for your application. http://speed-source.net/products/GT28RS.htm
or a GT3071R-WG http://www.tbdevelopments.com/catalog/p ... cts_id=202

Both will work out around £1500 ish IIRC and you must be able to flog your TD06-20G kit for £500?

After you have spent £500 polishing your existing turd it may not seem such a bad option

Having re-read the above - it seems I have had a bad day at the office! Sorry in advance and I don'y mean it to sound like mr opinionated & angry but I also can't be bothered to try and re-type it.

Either way m8 I would be interested in your chosen path, how it turns out and wish you well. Must be time for a beer soon Mook!

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

Haha, no worries mate, I understand the passion with which you write

I wouldn't go so far as to call it a bodge, but understand that it's making the best of an imperfect set-up. The TD06 was bought in the group buy from the US some years ago so was relatively cheap for a full kit, and by getting this one looked at it will mean it can unbolt then bolt straight back on with minimum hassle which is bob on for me.

It's not a bad set-up and once you're on full boost it goes like a train, though it is higher up the rev range than I would lilke for road application as you say.

If the surge is cured then we can look at feeding in boost as early as possible. Couple that with the bb bearing I'm hoping it will give it a little more workability, if you know what I mean.

I would ideally go for something with more modern technology, still keeping an eye on variable vein units to see if they become a more usable option sometime in the future, but I'm reasonably happy with the TD06 at present, so a little fettling should just make it a little nicer.

Sunny > My chargecooler set up is opmised with a larger pre-rad, giving more capacity as well as cooling, and the unit itself is heavily lagged with F1 engine bay material. The engine rad is an uprated Pace unit in aluminium, with a TRD sports thermostat. I've also added an engine oil cooler and relocated the filter, so all those aspects have seen improvements

You could look at Pace for a rad, or Koyo, and I believe there's also a company in Korea or similar that do then and sell a lot in Australasia, though I can't recall the name at present

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.

Mook,

Does the surge happen while the turbo is spooling?

Like this:

http://www.youtube.com/watch?v=nCj6Spwl1CU&feature=fvst

http://www.youtube.com/watch?v=OuNTnA5A2Fo

or when letting the throttle go.

http://www.youtube.com/watch?v=GmDpxmSH ... re=related



I have a GT3071 with a .63 housing and an external wastegate on my stock (exept for EMS) CS engine. I have the sound in the 3rd vid. When I let off the throttle. I also had it with the previous EVOIII (TD05 16G)turbo that I used. So swapping back to that doesn't help I quess.

This is all on 1 bar.

I would also cotact ATS or the company you bought your kit from, and ask if they sell a turbo of your liking that can be simply swapped out with your kit.

Would a bigger blowoff help?

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ST185 CS #1845

ST185pinjo > Mine is more like the first two, although nowhere near as pronounced, only a light fluttering which does pass when the revs get higher.

What you're getting, if it's like the third vid, is wastegate chatter which isn't anything like as bad. Quite normal to get that with external wastegate applicaions

_________________
'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.