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View Full Version : Need more power! Kinda slow at higher RPMs too.


Jason
07-08-2009, 05:05 PM
Ok I had a little grudge race with a buddy and his modded Jetta TDI. From a punch he pulled me, from a boosted launch he had me about a car and a half by 50mph or so. I've got lots of smoke, so lots of fuel... I haven't fooled with the waste gate, but I do have the dump valve plugged off and the turbo light is on, so I'm guessing I'm getting around 10 or 12lbs of boost. I have the exhaust straight piped, and stepped up to 2.5" out back over the axle, though its still 2" at the turbo. What I am noticing is that the car pulls pretty well once the turbo has spooled between say 2500 to 4k rpms or so, but above 4k it seems like its taking longer to wind out that last thousand RPMs or so to shift when its to the floor. I'm thinking it would be faster if I adjusted the kickdown cable so it would shift at around 4k rpms at WOT. What will help this thing pull harder at the higher rpms? I advanced the pump timing, though I haven't put a dial gauge on it. I scribed a line and tapped the pump over about a 32nd of an inch. There is a little more rattle and it is more responsive though. Any thoughts? I'm planning on doing my water meth setup tomorrow night and turning the boost up a little and see what goes...

Jason

Slobodan
07-08-2009, 05:59 PM
Its just the profile the camshaft that makes the peak power fall off after 4k or so. I've heard the D24's have a slight difference in cam specs, and ofcourse the D24 Intake is supposed to really kick ass on the Turbo setup.

reed
07-08-2009, 06:09 PM
Set the pump the correct way it takes all of 15min. Get a boost gauge from any parts store. T it into the hose that goes to the injection pump. Mine pulls to 5000 rpm. Im running the d24 na cam. Black smoke to the floor with the kickdown detent pushed, no smoke if I let up a little.

Check out this link, I want to get this book but havent. http://www.allardturbosport.co.uk/index.php?page=Turbo-Diesel-Tuning-Manual


Check this out good reading but set pump timing first. http://dodgeram.org/tech/dsl/more_power/Power_ve.htm#top

Jason
07-08-2009, 06:57 PM
I have also heard the na cam is a little more lift. I was thinking it felt like full power was done by 4k rpms. I am familiar with all the VE pump mods and have already tweaked the pump. I have had a few 12v dodge diesels and 1.6 diesels as well. Non of them reved like this thing does though. I hooked a boost gauge up to it tonight, and am pushing 22lbs by 5k rpms. Its at 15 and climbing by 4 grand. All I have is the dump valve plugged off. I'm guessing the waste gate must not be working. I have read most guys that plug off the valve get about 12 or 13lbs. My Jetta with the 1.6TD was the same way. It must be blowing nothing bot hot air though, as you really don't feel much difference from 10lbs at 3k rpms up to the 20 by 5k. In my jetta, when I turned the boost up to 17lbs from the 10 to 12 it was running, the difference was night and day. Even at 20lbs, its still smoking and I haven't even removed the fuel screw stop collar yet! I suppose it could just be over running the waste gate and it just cant bleed off enough to keep the boost under control... Who knows. I gotta get my water meth hooked up and I guess I'll open the dump valve up in the mean time before I blow the head!

Jason

reed
07-09-2009, 03:22 AM
Lift for the turbo cam and na cam are the same, from everything I could find. It may have to do with overlap. The turbo probably has no overlap where as the na would need some overlap for more torque.
Intake 8.5mm
Exhaust 9mm

Jason
07-09-2009, 04:42 AM
Interesting, I cant see why the NA cam would perform better with more overlap. You would be blowing your intake charge out the exhaust... Cant argue with the facts though. I have read in more than one place the NA cam ran stronger in the turbo engine.

I'm going out there now to mess with the waste gate and see if its frozen up.

Jason

reed
07-09-2009, 06:05 AM
The wastegate on the d24t is not adjustable, unless its aftermarket. I plan on using a mbc.

Jason
07-09-2009, 07:03 PM
Mine is not working at all. Now that I got full throttle after adjusting the pump again, I am getting up to 25lbs at 5000rpm. There is no way it should be going that high if the waste gate is working. The turbo is comming off so I can check it out. I may end up using another turbo all together unless I can find a good used waste gate. Anyone know what the deal is with the two hoses to the waste gate canister? One dumps back into the inlet of the compressor housing? Does that recuirculate some of the boost for some reason? I have never seen one with two hoses.

Jason

reed
07-10-2009, 01:39 AM
Its to drain oil back to the inlet. Are you sure the big hose to the wastegate is not broken. The wastegate is made to the turbo.

Jason
07-10-2009, 04:52 AM
Drain oil back to the inlet from what? Both hoses go to the top of the canister. Both hoses are in good condition as well. I think part of the reason its not pulling to hard at the upper rpms is the insane boost its trying to push. Lots of hot air, and I'm sure the drive pressure at that rpm with the turbo spining that fast is out of this world. That little .36 exhaust housing cant flow that kind of air.. I'll let you guys know what i find when I get it off there.

I'm thinking while its off a T-4 compressor housing upgrade!

Jason

reed
07-10-2009, 06:43 AM
You can have oil intering the turbo inlet from the crankcase vent hose. Its what Volvo say its there for.

cuaz64
07-10-2009, 03:13 PM
Well, based in information posted by Tom Bryant in turbobricks.com, the NA D24 camshaft "push" 2% more air to the engine, giving a almost 2% more power to the engine. I gonna post the Tom Bryant performance secrets soon.

Jason
07-11-2009, 04:10 AM
The waste gate canister is bad. When you blow on it, air does blow back into the turbo through that other hose, but its restricted like it has a calibrated orfice of some kind to bleed off pressure. Either way when I plugged it the diaphram still didn't hold pressure. Makes sense, as I was getting 25lbs of boost. I'm not impressed with the flow characteristics of the exhaust housing, 2/3 of the area of the inlet to the turbine directs flow to the waste gate. I'm going to reuse my center section and go probably with a .42 or .48 A/R hot side T3 housing and slap a .50A/R T4 cold side to really push some air. I may use a external waste gate depending on what exhaust housing I find. I'll post up some pictures when I get the stuff together.

Jason