Question about the way the turbo spools in my 1.6TD w/ K24 - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Question about the way the turbo spools in my 1.6TD w/ K24 by mk2vr6 on 12 May, 2007 05:51
• I believe the K24 is the stock KKK Turbo charger.  I know it is a KKK, I think its the K24 based on what I've read in here.
  
  Anyways...
  
  The way the turbo spools in my car is much much different than what I'm used to.  I'm used to the T04 in my VR6 which climbs out of vaccuum, from 1, 2, 3 psi, then spiking to 11psi right away.
  
  The turbo in the diesel seems to climb very linear, almost like a supercharger, with more and more psi as the revs go up.  It will climb rather slowly as well, and there is no apparent "spike" in power.  It does feel and sound as if it works properly though.
  
  However, I'm wondering if maybe this is due to where I tee'd the line for the boost gauge?  I did it on the boost line that goes to the LDA.  Also, could it be that for a boost control device I used a controllable bleed valve only?  And I did disable the pop-off valve as well.
  
  I also notice that while cruising on the highway @ 110km/h, its making 6 or so PSI, whereas my VRT would be in vaccuum, making no psi at all.  I know the diesels dont have vaccuum, but shouldn't it still be @ 0psi since the engine isnt under stress?
  
  Any ideas?  Could it be that I'm just not familiar with the way the turbo diesels work?
  
  Thanks guys.
• #1 by RabbitJockey on 12 May, 2007 08:11
• 6psi is a little high for 70mph, but not that bad... the turbo would spool faster with more fueling, then when it comes on, the car really comes on and pulls like a mule.  you also have to figure too that depending on your exhaust and the age of the turbo it's going to be slow.
• #2 by Black Smokin' Diesel on 12 May, 2007 19:22
• First and foremost, the way a turbodiesel works is very different than how a turbo gasser works but you probably know that.
  
  Plus the K24 isn't a very fast spooling turbo compared to a much smaller 1.9TD turbo or K03. A k24 is more of a high rpm turbo
  
  If you want it to spool faster you'll need a bigger downpipe (2.5").
• #3 by tylernt on 12 May, 2007 21:19
• The diesel turbos use different compressor and turbine wheel combinations (and I guess something called A/R which I don't understand) but apparently these make a difference in the way the turbo spools/boosts compared to a gasser, so you can't really compare the two.
• #4 by xud9te on 14 May, 2007 03:24
• Sounds like you either have a boost leak going to the guage, a boost leak from the turbop, or the wastegate is stuck open slightly.  I'd go for the latter, make sure the actuator allows the gate to close completely.
• #5 by mk2vr6 on 14 May, 2007 09:36
• Quote from: xud9te

  Sounds like you either have a boost leak going to the guage, a boost leak from the turbop, or the wastegate is stuck open slightly.  I'd go for the latter, make sure the actuator allows the gate to close completely.

  
  
  I'm pretty sure that stuff works fine, I was just asking about the speed at which the turbo spools, and I was mostly interested in finding out why it holds a boost charge while cruising (actually around 4psi @ 70mph) and not be at 0psi while cruising as in a gas car.  
  
  What size is the turbo exhaust flange?  Does it get restricted to a 2" exhaust size?  would it be best to get a 2.5" downpipe and back exhaust installed?
  
  Does anyone make a 2.5" DP for the 1.6TD already or do you have to get them custom made?
• #6 by rallydiesel on 14 May, 2007 09:44
• Dave at Passenger Performance makes 2.5 DP for the 1.6. He's in Canada too so you don't have to worry about broker fees/ duty with the shipping. The DP sells for $235 CD.
  
  
• #7 by rallydiesel on 14 May, 2007 09:48
• Oh, and if you get the rest of the exhaust in 2.5, just delete the mufflers/resonators. Your car will thank you  :shock:
• #8 by tylernt on 14 May, 2007 11:35
• Now that I think about it, the VR6 probably has more than enough HP to keep the car moving against rolling resistance and wind drag without really trying too hard, so the throttle butterfly isn't even fully open and hence is under vacuum.
  
  On the other hand, the little 1.6 (with what, half the displacement?) really struggles against that kind of load so you have to put your foot down more, which adds more fuel, which creates boost.
• #9 by mk2vr6 on 14 May, 2007 13:05
• That makes a lot of sense to me!  oh and thanks for the link to the 2.5" DP.  I just noticed he's from Canada too.  I'll have to get one of these on shortly.
• #10 by zagarus on 14 May, 2007 14:52
• Quote

  Oh, and if you get the rest of the exhaust in 2.5, just delete the mufflers/resonators. Your car will thank you  :shock:

  
  
  
  i just had my exhaust done by dave, 2.5 all the way, no resonators, no mufflers, nothing      and yes turbo spools a heck of a lot faster, but my turbo is the Garrett T3.
• #11 by mk2vr6 on 14 May, 2007 18:00
• Question about the passenger performance DP...  would this "Dave" fellow be willing to sell the rest of the exhaust system?  I ask because no one around here does mandrel bends and if I get the whole thing from him I'd be able to install it myself.
• #12 by burn_your_money on 14 May, 2007 18:09
• Dave's user name is 935racer, he has alot of posts in the Vendors section
• #13 by rallydiesel on 14 May, 2007 18:19
• I think just about any muffler shop could make a cat-back type exhaust for under $200.
• #14 by mk2vr6 on 14 May, 2007 18:29
• Well, thats what I had done, without a muffler.  it was about $180, but no mandrel bends and that included a resonator, and its only 2" pipe.