more turbo questions...sorry

[AntonUK]

Hi everyone I know you must all be fed up with people asking about turbos but I really cant get my head round it hope some of you could help me...

I cant decide wether to get a 1.6 turbo and get a larger compressor housing (or just leave it as is) or keep my GT25 (AAZ). Its really getting annoying trying to understand whats best option since nowdays diesels have smaller and smaller turbos (TDi's, HDi's etc). At the end of the day how much difference will changing a turbo make for my engine (1.9TD)?? Or could I play around with my turbo now make it bit more special?

Am I also correct in saying that the turbo whistle is from an imbalanced impellor?? Iv read that a perfectly balanced turbo makes no whistling noise at all. My turbo makes no noise (the cars done 150k miles) yet more or less brand new turbo diesels give off spool up whistle. I kind of like that spool up whistle.

Also is it worth reducing the compression ratio if Im to add boost?? up to 20 psi say?

cheers for any of your help!!!

[QuickTD]

If you haven't done extensive modifications to the fuel system, such as 1.6 LDA pin, governor and advance mods as well as added an intercooler, then you don't need to worry about the turbo for awhile. There is lots of power to be had without a larger turbo, that comes later...

[deepmud]

I would say work with the stock unit for at least to start. My 1.9td is making substantially more power and I haven't even intercooled it or gone a  far as I easily can with the stock turbo. And then I might go with some completely different turbo if the stock 1.9 one isn't making me happy. Certainly, I like the nearly instant throttle response. I think I only hear the turbo spool up nearly at idle rpm, and I have a straight pipe/no muffler. Your turbo spool up may be so quick you can't hear it through your muffler.

[moTthediesel]

Turbo tuning is a black art, rather like picking boat propellers, there are no easy answers.
Don't worry about that turbo whistle, it's not a sign that something is amiss. The KKK that I have on my Toyo 3B used to whistle like crazy under load when I ran it straight pipe, I miss it now that I have added a SuperTrapp muffler on the end of the pipe.

[AntonUK]

Yea I havnt yet done much not even intercooled it but Im planning to do it all at once while everything is out the engine. Im planning to take the head out to access the turbo and manifolds since it was such a job trying to take the turbo off in the engine bay and I may have rounded some bolts on the manifolds.

Do you think it will make any difference if I lower the compression ratio? Is it a good idea? Iv not heard any people doing this to TDs.

Reason I asked about the spool up whistle is that I always hear TDs out there whistling like mad with just old folks driving them and it makes me think why is my turbo being so damn lazy and quite :x ?! And reading that the whistle id from imbalance of the impeller makes me think why do new cars whistle surely their turbo is nicely balanced and new?? maybe its just my damn muffler :cry:

[fspGTD]

I don't know the details of your setup Anton, but on my Rabbit 1.6lTD when I replaced the thick, restrictive, cast iron upper downpipe that bolts on to the turbine outlet, and replaced with with thin-wall tubing instead, that let more turbine whistle through without having to replace or remove the muffler.  It's actually a useful sound IMO, it's sort of like a torque gauge for the engine.  Driving along at a constant speed, you can hear how the torque on the engine changes with any hills, downward slopes, etc by the speed of the turbine whine.

[type53b_gtd]

My little K03 (from a late AAZ) doesn't make much noise compared to a big K24 or Garrett (T2?)

You can hear it whistling a bit off idle, but when you get into it the "boomy" exhaust note from the 2.5" dual-outlett unbaffled magnaflow drowns it out - I'm sure the exhaust is actually louder with that muffler on the car than without any muffler...  Exhaust is A3 downpipe with a 2.25 mandrel grafted on - then a 2.5" techtonics centre pipe with no resonator.

As long as you've got boost, I wouldn't worry about the noise your turbo doesn't make...

Drew

[AntonUK]

Thanks for the comments.  So far Iv got intercooler lined up, Im going to have the injectors rebuilt, try to add fuel and up the boost.
Anyone have any idea of what sort of power Im looking at from these mods?? Anything else you think I can add to the extensive :shock:  list I have? Iv been reading about the gov mod but Ill see about that.

BTW how much louder will my car be without a back muffler?? or is it better to straight pipe the centre section??

Thanks guys, Anton.

[type53b_gtd]

The stock td is actually pretty quiet, so removing a stock muffler WILL make a noticeable difference.  However, the turbocharger serves to cut up the exhaust pulses from the cylinders, so the noise is nothing like an un-muffled normally aspirated diesel or gas engine.

It's one of those things you'd have to experience and decide for yourself.  If you're a fan of listening to classical music in the car, I would not recommend it.  If you live in a hospital (quiet) zone, I would not recommend it.  If your next-door neighbour works for the local constabulary and has been looking for a reason to nick you for something ever since you ran over his wife's cat, I would not reccomend it...

Drew