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Engine Specific Info and Questions => IDI Engine => Topic started by: Riverfurm on February 16, 2008, 05:11:37 am
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I had my 1.6 Turbo motor for about two month now and like it. It has a Giles Super pump, Pass. 3" down pipe, 3" exhaust and a Garret T3 turbo running 20 PSI max. When I get 10 psi boost the car really starts to pull all the way up to 20 psi and 5000 rpm. But off the line it still runs like my NA motor. Not much boost in first gear. Second gear boost starts coming in around 3800 to 4000 rpms. Third, fourth, and fifth come in a little sooner 3500. Is this typical. I find myself trying to keep the rpms up so I can stay in the boost zone. Is there a way to get boost sooner? I am happy with the boost control set at 20 psi I had it up to 30 but it did not seem to add much power so I keep it at 20. (Replaced the head gasket after a month, saw some leakage on the outside. Also installed head studs). Also mileage is anywhere from 34-39 typical (heavy foot???).
Any Help.....Thanks
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A got the smoke factor to a point I can deal with so I will leave the fuel alone. But I guess A smaller turbo is the easiest way to go.
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K14, baby !!
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or if you feel ambitious a G60 supercharger will give you boost way sooner!
but a K14 will do it easier like said earlier by Vince
thanks Duane
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slack out the starwheel spring,it really affects the response
so does turning the eccentric pin
i noticed a definate mileage decrease when i had the smoke screw turned in too far...not a big deal,it afects response too,but not like the starwheel
here i posted this in another thread a few mins ago
(http://img230.imageshack.us/img230/5681/veafchw4.jpg)
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I have this same slow boost issue with my T3. Dont have a tach yet so cant comment on the rpms but it feels similar to what your describing. It got worse after the intercooler install. My fueling is still stock and im contemplating what the best approach is for faster spool. I want more fuel at low rpms/boost to spool the turbo, but on the other hand I dont want it dumping tons of fuel in while cruising on the hwy at 5psi or so...yes I want my cake and yes I want to eat it :wink:
ps. my friends '96 Jetta AAZ will make 15psi at 2000rpm in 1st gear :shock: but the exh housing on the turbo is hardly bigger than the down pipe lol. Smallest turbo ive ever seen.
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the k14 is small but boost comes on very quickly especially with a little additional fuel. my cheapo intercooler makes it spool slower as well and does not keep efficient boost but i hope that the cooling benefits even it out or i am going back to no cooler. smaller turbo or bigger turbo? that is the question. i get 4 psi cruising at 60 all the time and that is nice, 15 psi max right now. it isnt too bad
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I'll try the starwheel spring adjustment first. But the K14 turbo sounds like the ticket. If it will run 20psi and start to spool up at 2000 rpm that would be great.
Thanks for the help.
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does the stock K24 spool up much more fast than the T3? anyone tried them back to back?
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Ok I did some testing on my car to see what is up. Basically I wanted to see if my boost controller was malfunctioning and causing slow boost.
This is the setup:
1.6TD
T3 Turbo
Small Intercooler
Stock Fueling
Stock downpipe
2.5" Mandrel Exh. no muffler
Boost Controller set to 15psi (everyday for the last couple months)
WG line clamped off (for this test)
Results:
No change. I couldnt get it to boost more than 15lbs even with my foot full on the brake and gas for XXseconds. Boost didnt come on any faster. Is there something wrong with my turbo or are T3's really just way too big? How much will more fuel help? Im hitting 1250F max EGT's. Its killing me waiting for boost...its like watching paint dry.
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Remember, there are 2 different types of "slow boost."
The one that most people forget is boost threshold. Turbos require a certain volume of air passing the turbine before they will even start making boost. This volume might equate to 2000 or 3000 RPM. This is determined by the sizing and geometry of the turbo, and it what's normally affected by changing to smaller turbos. Putting a little more heat to the turbo might help this situation a little bit, but if you are below this threshold you can brake torque it all day and never make boost. There's just not enough gas going past the turbine to get it up to speed.
The other is lag. Lag is the amount of time that it takes for the turbo to reach boost speed and pressurize the intake tract. It is determined primarily by the mass of the turbo internal parts and the mass of air in the intake tract. Lag is typically witnessed in the higher RPM range when going from steady state cruising to full power.
Boost threshold is the most annoying issue with turbos, but remember, a turbo that has the proper geometry for efficient high boost condition is typically larger and will not respond until higher RPM on smaller engines. Of course, if you are running a VNT, you can almost have your cake and eat it too.
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according to my favorite thread you need a 2.5 downpipe
http://www.vwdiesel.net/phpBB/viewtopic.php?t=1352&postdays=0&postorder=asc&start=0
My car is waaaaay faster now Very Happy. On Sunday and Monday I drove an hour to Brett's (DVST8R) shop and the following was done to the formerly stock 1.6TD:
1) Boost pin washer/spacer mod.
2) Electronic boost control. It's currently set at 24 PSI with barely any boost spikes. We ran it at 25 for a while.
3) Fuel injection quantity maxxed out.
4) Fuel governor mod.
5) 2.5" no-cat custom mandrel-bent downpipe to 3" exhaust (starts at bottom of downpipe).
6) EGT probe drilled in pre-turbo.
... and a few more. Big props to Brett for the help. I've had the TD for only a little over a week so I learned a lot during the process.
On Sunday I had leak in the back of the fuel pump where the cold start lever attaches to. We fixed that Monday. Rebuilding the fuel pump is a little easier than it looks.
So far the power is great, a big improvement. A friend of mine commented that it accelerates a bit harder than his MK3 VR6, but different torque curves can play tricks on the mind.
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there are 2 different types of "slow boost."
Very good point Gearhead. I cant count the number of times I have had to argue this. People always complain "OMG I have soooo much lag when I floor it from idle!".....well duh.
I drive over a relatively large hill every week (~1500ft elevation change over ~5km...~3min of full throttle at 110km/h). Even if I drive it in 4th at 110 (dont have a tach but fairly high rpms) I can maybe get it to creep to 17psi.
Im gonna try doing the mandatory boost pin/starwheel/etc. mods and see where that takes me before I go for the downpipe....I dont really feel like changing the turbo or messing around building a DP if i can help it.
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does the stock K24 spool up much more fast than the T3? anyone tried them back to back?
Also very interested in the answer to this
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I ran these turbo's back to back and the k24 spools a bit quicker than the T3.The k24 has a slightly bigger compressor than the T3 and the T3 has a noticably bigger Turbine than the k24.Beacuse the T3 has a bigger turbine it works better for mid range-top end performance and the k24 will provide better low-mid range performance.Both turbos are not efficent when pushed past 21 psi for k24 and 23psi for the T3.
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I ran these turbo's back to back and the k24 spools a bit quicker than the T3.The k24 has a slightly bigger compressor than the T3 and the T3 has a noticably bigger Turbine than the k24.Beacuse the T3 has a bigger turbine it works better for mid range-top end performance and the k24 will provide better low-mid range performance.Both turbos are not efficent when pushed past 21 psi for k24 and 23psi for the T3.
+1 I already try both turbo on AAZ, T3 and K24 (from 1.6TD) and yes the K24 spool a bit quicker.
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Just thought I'd update this as I have now done the following:
-Turned boost pin to max ramp
-Cut nylon washer in half
-Turned starwheel down 2 turns
-Unscrewed smoke screw untill it was just touching the top of the pin
-Turned max fuel screw in ~1/4 turn
-Adjusted idle screw to normalize idle
Results:
-Awesome
Turbo spools WAY faster now. I get a nice smokey cloud up untill 10-15psi then it clears up as boost builds to 20psi. Max egt's are about 1500F under a long pull, creeping towards 1600 if I do repeated pulls and heat soak the IC.
All this being said...its not like I have no turbo lag. The engine still needs to be in its midrange (dont have a tach) to make full boost, and even in the upper rpms, it takes a moment to build. It is still not a quick spooling as my friends '96 AAZ with K14/K03 (not sure which).
It is a huge improvement over what it was though.
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yeah i was going to say its definitely the fueling, under stock fueling i could never get more than 15psi. its amazing how much power the lda adds
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any news re. MPGs? have they improved?
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MPG have been affected minorly. My odometer doesnt work but I drive almost exactly the same amount each week (put in exactly 32L per week for the previous month or so) and this last week since I did the mods I put in 35L. That was including my first day of autocross in the golf however so im sure that burned some fuel. Overall I couldnt be happier.
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Those are kind of high EGT's, at least higher than I would run..
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yeah, I try to stay under 1200F
but then I turboed an N/A
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If I want to make more smoke the boost will come on sooner but, it soots up the rear of the car. I just hate the offline performance. A small amount of boost in first, second almost full boost at 3800rpm(20 psi) 3rd, 4th and 5th full boost from 3000 rpm up. So when I pull away from a light the traffic passes me, by the time I hit 3rd gear I am passing them with some smoke. Exhaust temps rarely get above 1050 F. I use this car as my shop vehicle. It has about 200 pounds (don't know what that is in Kilos) of tools and parts. Best MPG was 40+ highway.But it is still fun to drive.
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Those are kind of high EGT's, at least higher than I would run..
I suppose...but my car has always run hotter than others on here it seems...it was running this hot completely stock (stock boost, fueling, exhaust, no IC etc.). It will run at 1200F just holding speed up a small incline at hwy speed (making NO smoke). I have yet to check the timing so maybe that has something to do with it but it starts/runs fine so I never really bothered.
Also, when I say 1500F on a long pull, it'll only get there in 4th or 5th if I do a drag race start from 1st, or have a long stretch of hwy and pull up to 150kph or so...which really never happens during daily driving so im not too concerned. Ive yet to read anywhere of someone melting/blowing "X" part at "Y" Deg F EGT, its all just random claims of peoples comfort levels so untill I melt a piston Im happy :twisted:
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When I was drag racing snowmobile I ran an egt gauge and when it hit 1200F I knew the pistons where getting soft so I backed off it for a second and the temps. dropped down. If it hit 1500F that was a major melt down.
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An appropriately sized vnt turbo will offer virtually instant boost and yet better flow than a conventional turbo at higher flow/rpms. The downside is the added complexity of an adequate vane control system and completely custom installation.
Andrew
Any chance of you offering a Vane Control System kit?