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Engine Specific Info and Questions => IDI Engine => Topic started by: barrygti on April 09, 2009, 11:46:59 pm

Title: What's your boost threshold?
Post by: barrygti on April 09, 2009, 11:46:59 pm
Ok guys can we get a list of:

Engine
Turbo
Boost Threshold
Boost Level
Power if known

Might help some, including me, work out what turbo to use. Have a nagging feeling my Land Rover turbo will be too big.......  :lol:
Title: What's your boost threshold?
Post by: AudiVWguy on April 10, 2009, 08:17:18 am
How do you define boost threshold?  
Boost level--at a certain rpm and gear, highway, max boost? Just trying to understand what you want.
Thanks
Title: What's your boost threshold?
Post by: barrygti on April 10, 2009, 12:30:11 pm
Yes, at what RPM do you reach maximum boost loaded in maybe 3rd or 4th gear?
Title: What's your boost threshold?
Post by: zukgod1 on April 10, 2009, 02:10:36 pm
Well my personal Boost Threshold is about 35 psi, beyond that I start to get nervous.  :lol:


But on a bit more serious level.

Personally I wouldn't take a stock 1.6 with a 24 over 30 psi and expect it to hold together long. The stress on the turbo will be less the higher you get using a larger turbo but the lag will be nasty, meaning @ 30 psi a 26 may be at it's limits before it blows up and a Garret T4 with say an 60mm compressor and a .48 exhaust can run @ 30 psi all day but your going to spool the 26 way sooner in the RPM range than the T4

Problem is we really need to be talking about CFM instead when we are talking about turbos. A k26 can run @ 25 psi as can a k14 but the 14 will be pushing HOT air and have to work much harder to get it.

Here's the problem as I see it.

Everyone here want's BIG boost, my self included. Then when we get it we realize it sucks! I just bought an 02 Passat with a gasser 1.8t (I know I know) and it has a k03 on it. Damn near the smallest turbo I have ever seen on a car this size but holly crap does it perform!

Now when I first built my car (jetta diesel)I had a stock k24 on it and it was fun, well that wasn't good enough for me I wanted more! I built a 26/24 hybrid and bolted that baby on, holly crap talk about power! But it was a DOG at anything under 3000 rpm.
Cruising down the freeway @ say 75 mph I was turning about 2700 rpm, if my cruise control tried to compinsate for a hill the smoke out the back would black out the freeway, that wasn't to good for economy not to mention I actually got pulled over and cited for it once.

Now had I been running a k14 the turbo would have lit and the smoke wouldn't have happened.

You need to decide (as we all do) what youwant/ need your car to do. Build from there.
In my opinion going with a turbo that is smaller than what you think you want is going to be perfect.


I'm rambleling now so i'm going to shut up.....
Title: What's your boost threshold?
Post by: zukgod1 on April 10, 2009, 02:20:34 pm
For giggles.

Smallest is an k03, middle is k24 larger is k26.
I should have put something there for size reference sorry.

(http://i176.photobucket.com/albums/w168/zukgod1/MK2%20Project/1239392154357.jpg)

The one in my hand is an exhaust wheel from a k24 the one in the housing is the k03

(http://i176.photobucket.com/albums/w168/zukgod1/MK2%20Project/1239392152698.jpg)
Title: What's your boost threshold?
Post by: barrygti on April 10, 2009, 03:46:21 pm
What you have discussed is my great fear. I don't want to ring the neck of a smaller turbo as I believe it places more stress on EVERYTHING.

However I am worried my BV50 even with VNT will not start boosting till 3k rpm, maybe full at 3500rpm and be all done and over by 5k.

However I also don't want a 30psi hit at 1900rpm and have component killing torque.

Wish I could find a damn compressor map.
Title: What's your boost threshold?
Post by: andy2 on April 10, 2009, 06:47:43 pm
Excellent advice zukgod1  :wink:
Title: What's your boost threshold?
Post by: blackdogvan on April 10, 2009, 08:04:12 pm
Quote from: "barrygti"
What you have discussed is my great fear. I don't want to ring the neck of a smaller turbo as I believe it places more stress on EVERYTHING.

However I am worried my BV50 even with VNT will not start boosting till 3k rpm, maybe full at 3500rpm and be all done and over by 5k.

However I also don't want a 30psi hit at 1900rpm and have component killing torque.

Wish I could find a damn compressor map.


Whats the disp, hp & tq @ RPM numbers from the engine that turbo is off??
Title: What's your boost threshold?
Post by: barrygti on April 10, 2009, 10:49:38 pm
Quote from: "blackdogvan"

Whats the disp, hp & tq @ RPM numbers from the engine that turbo is off??


2.7 V6, 190bhp at 4000rpm, 325lb/ft at 1900rpm

I used to work on these vehicles and they do come in nice and strong so I am hoping the turbo is on the small side in order to increase torque due to being a 4x4.
Title: What's your boost threshold?
Post by: Smokey Eddy on April 11, 2009, 04:00:31 am
i find my t3 is too big for "fun" daily driving. But when i dont mind spending the extra money on diesel it will perform if i feed it enough.

Foot to the floor pushing 25psi PLUS it's quite the torque monster. but... driving around town you never get over 10 without really wasting fuel... driving conservatively but comfortably it [with my build] will make maybe 4-6 pounds?

just my experience...
your mileage may vary:)
Title: What's your boost threshold?
Post by: barrygti on April 11, 2009, 04:49:59 am
Is that the standard T3 you are running?

What sort of power/torque do you make as your engine is along the lines of what I am doing.

Do you use the standard 1.6 pump and injectors?
Title: What's your boost threshold?
Post by: g-spec on April 11, 2009, 10:35:31 am
Im currently running a T3 on my 1.9 AAZ peaks at about 30-35lbs. But my friend is willing to give me a t3 super 60 he has and Im gonna try and build that for my 1.9. I want to use the cold side from the super 60 and the turbine from the diesel t3.

What do you guys think about something like that??
Title: What's your boost threshold?
Post by: Rabbit on Roids on April 11, 2009, 10:55:19 am
Quote from: "g-spec"
Im currently running a T3 on my 1.9 AAZ peaks at about 30-35lbs. But my friend is willing to give me a t3 super 60 he has and Im gonna try and build that for my 1.9. I want to use the cold side from the super 60 and the turbine from the diesel t3.

What do you guys think about something like that??


i think its gonna take DAYS to spool something that big.. considering they run those on pretty big engines. arent they spec'd for something big? like 4 litres and above?
Title: What's your boost threshold?
Post by: barrygti on April 11, 2009, 12:46:36 pm
A Super 60 is a 400bhp turbo on a VR6 etc I think so may be a bit big. And if you go too big and the engine can't consume the air you will probably get surge.
Title: What's your boost threshold?
Post by: g-spec on April 11, 2009, 05:22:54 pm
The t3 super 60 isnt that big....guy run it on turbo 1.8-2.0. It would be way too small to run on a vr6. I think it would be a little big for a diesel but with a proper pump I think it could yield some nice power.
Title: What's your boost threshold?
Post by: zukgod1 on April 11, 2009, 07:38:45 pm
Quote from: "g-spec"
The t3 super 60 isnt that big....guy run it on turbo 1.8-2.0. It would be way too small to run on a vr6. I think it would be a little big for a diesel but with a proper pump I think it could yield some nice power.



Sure it could, At 4000 rpm and up.. If that's where you want to run fab it up and go.  8)
Title: What's your boost threshold?
Post by: jtanguay on April 11, 2009, 08:03:46 pm
Quote from: "barrygti"
Quote from: "blackdogvan"

Whats the disp, hp & tq @ RPM numbers from the engine that turbo is off??


2.7 V6, 190bhp at 4000rpm, 325lb/ft at 1900rpm

I used to work on these vehicles and they do come in nice and strong so I am hoping the turbo is on the small side in order to increase torque due to being a 4x4.


the fact that the turbo allows the engine to produce 325 lb/ft @ 1900 rpm shows you how well the turbo spools down low, and that its a VNT.  i think that this turbo would be well suited to a 'hopped up' 1.9 diesel engine.  the lag would be comparable to running a K24 i would imagine.
Title: What's your boost threshold?
Post by: AudiVWguy on April 11, 2009, 10:07:13 pm
If this is used on a 2.7 ltr engine, is there a way to figure out many CFM of air is running through the turbo at 1900 engine RPM?
Then see what RPM the 1.9 motor has to spin to make the same CFM.

The only problem I can see with this theory is that it might be related to how much fuel (load) is applied. There is more heat generated (expanding exhaust gas) from a 2.7 than a 1.9.

Am I over thinking this?  :shock:
-JB
Title: What's your boost threshold?
Post by: barrygti on April 11, 2009, 10:47:57 pm
I will be runnning a 1.6 bottom end though so even worse......

I am going to give it a go, if it sucks I will put the T3 on there. I am sure Land Rover run them very lean for emissions so with a bit of smoke and the ported head etc I hope it will work ok.  :lol:

See my project thread.
Title: What's your boost threshold?
Post by: scottcoreyv on April 11, 2009, 10:55:35 pm
Im running a S1B switzer, with no wastegate on a 1.9 AAZ and it will start to spool at 2000rpm and will peak at 30psi at around 3800rpm but i had to modify the pump to get it that high otherwise it would only hit around 8psi. Its good around town as well as on the highway were it will sit around 3psi crusing
Title: What's your boost threshold?
Post by: barrygti on April 11, 2009, 11:00:07 pm
Quote from: "scottcoreyv"
Im running a S1B switzer, with no wastegate on a 1.9 AAZ and it will start to spool at 2000rpm and will peak at 30psi at around 3800rpm but i had to modify the pump to get it that high otherwise it would only hit around 8psi. Its good around town as well as on the highway were it will sit around 3psi crusing

What vehicle does that come on standard? I would be happy with that sort of spool range as I think the top end will be worth it.

Can I ask what you done to the pump, or do you just mean fuelling adjustments?
Title: What's your boost threshold?
Post by: UnderPSI on April 11, 2009, 11:35:18 pm
A 2.7 flows 6.25 lbs/min at 1900 if it had 100% volumetric efficentcy. A 1.9 will flow the same considering 100% ve at 2700.

S1b Schwitzer can be had new for around $400.
Title: What's your boost threshold?
Post by: barrygti on April 11, 2009, 11:49:21 pm
So it's not un-reasonable to expect full boost on a 1.6 at around early 3000rpm range??? Perfectly fine by me if it will then hit 200bhp!!  :lol:
Title: What's your boost threshold?
Post by: UnderPSI on April 11, 2009, 11:58:39 pm
A 1.6 would be 3200.
Title: What's your boost threshold?
Post by: barrygti on April 12, 2009, 12:09:06 am
Yep that's what I just worked out too, but I would assume that's full boost if the peak torque of the 2.7 is delivered there, so that would mean it should start spooling earlier with full boost(dependant on level of course) at around 3200rpm, hopefully continuing to around 5000rpm will give a nice enough power band.
Title: What's your boost threshold?
Post by: RabbitJockey on April 12, 2009, 09:09:52 am
i think the only way to know is to try it.  u could plug numbers all day and get an idea of what you need but until you try it you won't know, there are so many different styles and sizes of wheels.
Title: What's your boost threshold?
Post by: UnderPSI on April 12, 2009, 10:05:32 am
Quote from: "Trev0rbr"
i think the only way to know is to try it.  u could plug numbers all day and get an idea of what you need but until you try it you won't know, there are so many different styles and sizes of wheels.




It's a T3 Super 60 actually.
Title: What's your boost threshold?
Post by: TurboJ on April 12, 2009, 03:34:01 pm
A Super 60 will support around 300 hp on a gasser 2.0, and that means it should be able to make 200+ hp on a diesel of the same size with little trouble.

As for spool-up, on my 2.0 Saab I got a T3/T4 since a super 60 would've been too small. Even the T3/T4 gave full boost at 3000 rpm.
The difference in spool-up between the T3/T4 and the stock T3 wasn't dramatic, however the effect of spool-up definetely was!
Since a normal gasser T3 works fine on IDI VWs (experience from another guy), a super 60 should be just just as good, given the fact that even with a T4 compressor the T3 does not have that much slower spool-up vs a standard one.
Title: What's your boost threshold?
Post by: zukgod1 on April 13, 2009, 12:38:48 pm
Looking forward to your results.

just like everyone else here I love BOOST!!!!!!