best Turbo - page 4 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• #45 by vwmike on 16 Nov, 2005 12:30
• Quote from: "DVST8R"

  I don't know anyone on the Hardcore forum running a TO4E 50trim with a .48 T3 Turbine, most people running that big of a compressor run a .63 or .82 or a full T4.

  
  
  Yes, they would run a larger turbine to reduce backpressure. They also have much more exhaust heat to spin the turbine and high rpm power levels which depend on reduced backpressure. I run a rediculous turbine on my Rabbit. I don't even get full boost (generally 16-18 psi) until 3rd gear and barely even use the wastegate. I think of it as traction control though. If it fully spooled in 2nd it would just start spinning the tires. It already does that on the freeway if it's wet out.
  
  
  

  Quote from: "DVST8R"

  
  I agreee 100% The T4 is not what you want on a 1.6 diesel, however we are back to comparing apples to oranges becuase the motor that it is going on isnt anywhere close to a normal 1.6 diesel. Dave was wrong to post way back about this turbo with a cam would be a have your cake and eat it too , event. It is not nor is it intended for general public consumtion. This topic started out as "the best turbo" this is not it, but I will have to wait for the actual dyno test to prove my thoery.

  
  
  Unless you plan to rev it extremely high then it is still unlikely that you'd find it to be efficient. A 1.6 is still a 1.6. It still displaces 1.6 liters and if you've accmoplished anything by improving the breathing it would be increased volumetric efficiency and an altered power curve increasing the rev range and upping horsepower due to the increased peak RPM.  Even so, I don't think horsepower is going to peak high enough to see benefits from the T4 compressor.
  
  I'm not trying to be insulting here or anything. I just see the numbers and I have to agree with VWRacer. Twins is the only way to go to do what you are trying to do. I've already decided that I'm going to do this myself, but it will take some time to make everything come together.
• #46 by DVST8R on 16 Nov, 2005 12:32
• Quote from: "VWRacer"

  Please don't take my comments out of context, 935racer. I am not some troll from the vortex baiting you with assinine comments. I've engineered two national road racing championships in the past 3 years (Formula Altantic in 2003 and C-Sport Racer in 2005), so I know something about making engines (and cars) go fast.
  
  The bottom line is that the numbers don't lie. Take a look at vwmike's figures...at 4500 RPMs you need 22 lbs/min of air at a pressure ratio of 3.1. The TO4E's maximum allowable pressure ratio is only about 2.4 at that air flow. Go above that and you will exceed the turbo's surge limit. The T3-50 is a better choice, but as you can see from the graph you aren't pulling anywhere near the RPMs required to get that one into a reasonable efficiency.
  
  For both 935racer and Mark Malone (and please don't take these comments as negative), I think your G-Techs are giving you bogus numbers. That's because the G-Tech computer program is based on a normally aspirated engine - and a gasoline one at that! A turbocharged diesel is going to give the G-Tech fits, so it is really only good for measuring relative improvement; the change in performance after you make a change to the car. You can't reliably read horsepower from it. To get reliable numbers you will need a good engine or chassis dyno. So my advice is stop talking about horsepower - you can't get any reliable numbers for it so you're only fooling yourselves (and your customers) to even bring up a specific number.
  
  Mark, you can't directly compare your engine's hp to your friend's VR6. That's because the two engines have completely different performance characteristics. You are pulling him because your TD is making massive torque across a wide RPM range, whereas his engine makes relatively low torque and has to be wound to the sky to make hp. If your G-Tech says you're getting 140 hp at 4500 RPM from the car's actual acceleration, we can solve for your engine's corrected torque by using the standard horsepower equation: HP = (Torque*RPM)/5252.
  
  Using a little middle school algebra, we can solve for torque: T = (HP*5252)/RPM
  
  In your case, that's (140*5252)/4500 = 163 lbs-ft of torque at 4500 RPMs.
  
  A 1999-2003 1.9l TDI makes a dyno-verified corrected 90 hp and 155 lbs-ft, so from that I'd say you're making a corrected horsepower of about 100 hp. Not bad, but do you really think you can double that from where your engine is now? I don't know, but I don't believe you can with one turbo.
  
  In the end, to make the magic 200 hp from a 1.6TD, I believe we're going to have to add another turbo, especially if we want a drivable car, as well.

  
  
  First I have the utmost respect for the accomplishment of the members of this board, many have been racing and building motors since b4 I could walk. I have had my hands on wrench's since I could squeeze my fingers together, and alot of time has been spent in the building of competition pulling tractors. Where I have learned that the best theroies are often wrong when it comes to reality essptially in the world of performance diesel, as there just isnt the time and effort and R&D into this fuel sorce as there is for gasoline. With that being said, I am extatic that this has created enough controversy that it is actulaly being discussed. Let us try and keep it at a disscution where we still "hear" each other and not a argument where its just about being right or wrong.
  
  Here inlies the next problem with the above G-tech. It only has till the wheels start to spin, as well it has not been reved to anywhere near its full potential, the FMIC is not on, and it is still drasticly underfuelled.
  
  So what we are seeing in that G-tech is not anything like the car that we will see when the big turbo goes on and it goes to the dyno. About the only thing that can be taken from that is. This pump when it was on a stock motor created so much fuel "black smoke" that it was almost undrivable, it could easly fill three lanes of trafic with smoke with some mild acceleration. It would also hit EGT's in excess of 1800 degrees within seconds and was the ultimate demise of the stock motor.  
  
  With the modified engine still unintercooled, the pump has had to be turned up significantly just to produce a faint haze, as well the EGT's if I am not mistaken will not climb above 1100degrees in any circumstance tried so far. What we are seeing is a Massive increase in airflow, as well as a shift in VE vs RPM as well as a possible increase in VE though that is just a guess untill it is dynoed. With more airflow / density to come. Which is why it is my opinion that we are not only comparing apples to oranges when comparing this to a stock or stock modified 1.6TD, but it will be fuel if anything that will hold us back from 200whp.
• #47 by malone on 16 Nov, 2005 12:40
• Quote from: "VWRacer"

  For both 935racer and Mark Malone (and please don't take these comments as negative), I think your G-Techs are giving you bogus numbers. That's because the G-Tech computer program is based on a normally aspirated engine - and a gasoline one at that!
  
  A turbocharged diesel is going to give the G-Tech fits

  
  
  Please elaborate. Most people fail to realize how important it is to properly calibrate a Gtech. The old Gtech Pro model from 1994 also does not have a RPM calibration feature so you cannot adjust to 4,500 RPM as desired. The latest Gtech models work best.
  
  

  Quote

  So it is really only good for measuring relative improvement; the change in performance after you make a change to the car. You can't reliably read horsepower from it.

  
  
  I agree, I even stated that a few times in this forum a while ago. Gtech's net hp is not the same as wheel or crank hp. I'm more fond of the Gtech torque & hp differences between my old stock 1.6TD vs. my current setup than my current setup's #s alone - "140 net hp".
  
  Currently I can indeed only guess wheel hp; I never said that it is totally accurate. I mentioned looking forward to dynoing the car at www.kineticmotorsport.com for more credible figures.
  
  I have Gteched several TDIs, from stock to chipped + nozzled. Many chipped and nozzled ALH TDIs with VNT-15 turbos usually put down 120-130whp on a dyno. They all report approx ~110 net hp on my Gtech quite consistently. Numbers for stock 90hp TDIs were a consistent 75-80 hp on Gtech.
  
  Gtech requires proper calibration and I think I have more experience in handling the device than you do. I still think my 150whp guess is quite close.
  
  Since you said Gtech are useful for comparing differences after mods.. let's look at the following, my 1.6TD in stock configuration vs. my present configuration:
  
  
  a 52 net HP from a stock 1.6TD vs. 132 net HP from my 1.6TD in its recent configuration is a 2.54x gain.
  
  Calibration is spot on for both runs.
  
  You may then agree that in theory a 69bhp 1.6TD multiplied by 2.54x gain results in 175bhp, which is still on par with my conservative 140nhp -> 150whp guess (based on a VR6's 132nhp result).
  
  Also note that while Gtech numbers are lower than wheel hp.. the difference between a stock 1.6td and my 1.6td will be magnified on the dyno with wheel hp figures.
  
  Anyway, there isn't much point to continue in this discussion. A dyno for this 1.6td isn't far off; I'll post a dyno plot then
• #48 by DVST8R on 16 Nov, 2005 12:46
• Quote from: "vwmike"

  Quote from: "DVST8R"

  I don't know anyone on the Hardcore forum running a TO4E 50trim with a .48 T3 Turbine, most people running that big of a compressor run a .63 or .82 or a full T4.

  
  
  Yes, they would run a larger turbine to reduce backpressure. They also have much more exhaust heat to spin the turbine and high rpm power levels which depend on reduced backpressure. I run a rediculous turbine on my Rabbit. I don't even get full boost (generally 16-18 psi) until 3rd gear and barely even use the wastegate. I think of it as traction control though. If it fully spooled in 2nd it would just start spinning the tires. It already does that on the freeway if it's wet out.
  
  
  

  Quote from: "DVST8R"

  
  I agreee 100% The T4 is not what you want on a 1.6 diesel, however we are back to comparing apples to oranges becuase the motor that it is going on isnt anywhere close to a normal 1.6 diesel. Dave was wrong to post way back about this turbo with a cam would be a have your cake and eat it too , event. It is not nor is it intended for general public consumtion. This topic started out as "the best turbo" this is not it, but I will have to wait for the actual dyno test to prove my thoery.

  
  
  Unless you plan to rev it extremely high then it is still unlikely that you'd find it to be efficient. A 1.6 is still a 1.6. It still displaces 1.6 liters and if you've accmoplished anything by improving the breathing it would be increased volumetric efficiency and an altered power curve increasing the rev range and upping horsepower due to the increased peak RPM.  Even so, I don't think horsepower is going to peak high enough to see benefits from the T4 compressor.
  
  I'm not trying to be insulting here or anything. I just see the numbers and I have to agree with VWRacer. Twins is the only way to go to do what you are trying to do. I've already decided that I'm going to do this myself, but it will take some time to make everything come together.

  
  
  I do not see it as insulting at all I see it as very informative disscustion on turbo's  :wink:
  
  I understand the reasons for going to a bigger turbine (not that you insinuated that I didn't) which is one of the reason's I thought it best to stay with the .48 housing to decrease the RPM at which it begins to spool at the expense of more back pressure, if I was runing a twin setup it would be compeltley opposite.
  
  I also think that for a daily driver, or for a "fun" road car twins are absolulty the way to go. Mark stated previously that it was the initial plan and is still the plan to go with twins, the reason that we are not right now, is two fold, one the cost of the appropriate second turbo, and second the cost of custom rods. I know with out a doubt in my mind that if we put twins on that car that we would break rods in a matter of weeks, if not days, destroying a brand new $$$ motor in the process. The only real way of knowing how well or how lousy this setup will be is to throw it on as strap it do the dyno and giver'  :twisted:
  
  However to this point in the disscustion I still feel satisfied with the T4 compressor for what we are trying to achive. With that being said if I can get an HX35 compressor instead for about the same cost... it will be run!
• #49 by DVST8R on 16 Nov, 2005 12:48
• Quote from: "T-hane"

  What is the best turbo to put on a 1.6 that is a direct bolt on and will see good all around results

  
  
  Who would guess that a simple question like that would spark 4 pages of turbo disscution  
• #50 by malone on 16 Nov, 2005 12:56
• Quote from: "VWRacer"

  If your G-Tech says you're getting 140 hp at 4500 RPM from the car's actual acceleration, we can solve for your engine's corrected torque by using the standard horsepower equation: HP = (Torque*RPM)/5252.
  
  Using a little middle school algebra, we can solve for torque: T = (HP*5252)/RPM
  
  In your case, that's (140*5252)/4500 = 163 lbs-ft of torque at 4500 RPMs.
  
  A 1999-2003 1.9l TDI makes a dyno-verified corrected 90 hp and 155 lbs-ft, so from that I'd say you're making a corrected horsepower of about 100 hp. Not bad.

  
  
  We're talking about an IDI 1.6 here with a shorter stroke and a significantly different powerband.
  
  For starters, my torque peak (163lb-ft) is around 4,000 RPM and the 1.9L TDI's is at roughly 2,500 RPM (155lb-ft). My Gtech's RPM calibration is spot-on and its accelerometers can gradually sense the increasing G force at 4,000 RPM. I can confirm it in the seat too.
  
  I'm still stumped as to why you think Gtech is less accurate in a diesel vs. a gasser. This leads me to believe you've barely operated a Gtech, if at all.
  
  After you proclaimed yourself as a race engine builder, I'm quite surprised that you used a stock 1.9L TDI to calculate my 1.6L IDI's 100 wheel HP figure.
  
  I'm not being fooled by the torque, and I know how easy that is. During high RPM it easily pulls harder than a VR6 during higher RPM. Still will need a dyno to remove anyone else's doubts though.
• #51 by DVST8R on 16 Nov, 2005 13:01
• Quote from: "malone"

  
  After you proclaimed yourself as a race engine builder, I'm quite surprised that you used a stock 1.9L TDI to calculate my 1.6L IDI's wheel HP figure. That is incredibly off.

  
  
  Mark that was a little harsh don't you think? Rember this is just a friendly disscustion.  :wink:
• #52 by 935racer on 16 Nov, 2005 13:05
• VWracer I wasn't trying to offend you but really, every performance engine builder including myself knows that not everything works out on paper. Hence R&D, if it was as easy as just doing it on paper no one would blow up engines, and that would be some boring R&D
• #53 by VWRacer on 16 Nov, 2005 14:35
• No offence takem 935racer...and none intended.
  
  Mark, thanks for adding the amplifying information. I was just responding to your question about getting 200 hp from a 1.6TD given the information you included, so may have missed out on some of your assumptions. Please believe me that I am not trying to insult you or 935racer or otherwise trying to denigrate your projects. I'm just trying to share some tools for getting better results.
  
  But now that you mention it Mark, yes, I am a race engine builder, having build literally dozens over the years. Not only that, I am a professional race engine builder, since now I actually get paid to do it (or at least spec it to the shops that do the work). :lol:
  
  And while that doesn't make me an expert on diesels, I do have the tools and experience to objectively evaluate basic performance characteristics of high performance engines. Furthermore, I know that G-Tech itself acknowedges that their older meters are not reliable on turbocharged engines. How do I know? Because the booklet that came with my G-Tech says so!
  
  If you have a more recent model of G-Tech, perhaps it is more accurate than mine, but you yourself quote numbers has high as 15% low for stock TDIs. Personally, if I had a dyno reading 15% off what I knew to be good numbers, I would suspect the accuracy of said dyno. That having been said, let's look at the newest dyno report you post. The report gives max torque as 154.5 lbs-ft (pretty close to what I calculated above, BTW). Plugging that value and your corrected RPM into the equation I provide above:
  
  HP = (Torque*RPM)/5252, so (155*4000)/5252 = 118 hp.
  
  Virtually identically to the horsepower shown on the plot at 4000 RPM, so obviously G-Tech have improved their computer model in that RPM range.
  
  

  Quote

  I'm still stumped as to why you think Gtech is less accurate in a diesel vs. a gasser. This leads me to believe you've barely operated a Gtech, if at all.

  
  FWIW, I've had one for a couple of years and have run it on an '02 TDI, '00 PSD Excursion, '84 Quantum TD, '89 Chevy, '75 E-250, and a 1993 turbo Eagle Talon with widely variable results (from right on with the TDI to hopelessly optimistic for the Quantum (it reported 74 hp for an engine with 210,000 miles and a slipping clutch that made less than 70 hp new)).
  
  As for why a G-Tech can read a diesel incorrectly (or more precisely a boosted engine), one need look no further than the combustion characteristics of the two engine types. N/A gassers hit peak cylinder pressure shortly ATDC, which then falls rapidly as the piston slides down the bore. OTOH, a diesel has a lower ATDC peak, but then maintains much higher pressure for the remainder of the power stroke since it continues to inject fuel for a goodly percentage of the stroke. The result is a vastly different BMEP curve. At least in G-Tech's earlier models this led to erroneous diesel (and turbo in general) readings.
  
  As I said, I was responding based on the information you posted. Sorry if I missed some relevent information. One thing does puzzle me, though. On the previous page you wrote, "Chances are good I'm making at least 150whp now." Yet the G-Tech plot you add just above reads 132 hp. Why the discrepancy?
• #54 by 935racer on 16 Nov, 2005 14:55
• Vwracer, the reason the g tech reads lower is because it factors in things like aerodynamics. As mark posted earlier he has had consistant results with different engines making less hp than they have on a dyno, the reason being that the gtech factors in the other short commings the vehicle has that aren't affected on a regular chasis dyno. Do to the consistancy of the results I would say the gtech is quite accurate for net HP. And it is extremely useful for before and after modifcations and comparing hp and torque curves. I don't have my own gtech I use marks but I have tested it in many cars and mark has used in probably double or triple the amount of cars I have used it in. Hopefully the rain keeps up today as mark and I are planning and doing some more tuning with his car and will post up some more gtechs.
• #55 by malone on 16 Nov, 2005 15:10
• Quote from: "VWRacer"

  If you have a more recent model of G-Tech, perhaps it is more accurate than mine, but you yourself quote numbers has high as 15% low for stock TDIs. Personally, if I had a dyno reading 15% off what I knew to be good numbers, I would suspect the accuracy of said dyno.

  
  
  I may be misunderstanding you, but are you saying that you'd expect the GTech numbers to be close to wheel hp (dyno) or crank hp numbers?
  
  As Dave said, aerodynamic drag and other friction losses are experienced in a moving vehicle while the Gtech's in operation, unlike on a dyno, so the lower Gtech numbers (lower than wheel numbers!) are normal. This is called "net" horsepower and it is distinctive from "wheel" horsepower. This is explained in detail in the Gtech manual.
  
  

  Quote from: "VWRacer"

  On the previous page you wrote, "Chances are good I'm making at least 150whp now." Yet the G-Tech plot you add just above reads 132 hp. Why the discrepancy?

  
  
  That is no discrepancy.
  
  A 172bhp 12 valve VR6 usually produces 155whp on a dyno. The VR6 produces 130-135nhp according to Gtech and this is a perfectly normal and consistent reading.
  
  If you see 90nhp (Gtech hp) in a stock 90HP ALH TDI then your Gtech is improperly calibrated. Gtech hp numbers can be inflated by simply entering too high of a vehicle weight, which makes Gtech think the engine is working harder to move the vehicle at the measured speed. This is a very common mistake.
  
  Most people do not bother going to vehicle scales to record the correct weight. If they see too low of a HP number on Gtech, they think something is wrong and then they tend to increase the vehicle weight. Very common. The problem? They didn't bother reading the instruction manual or they just want to make their numbers look nice, especially to post on the Internet. I keep my numbers conservative.
  
  

  Quote from: "VWRacer"

  That having been said, let's look at the newest dyno report you post. The report gives max torque as 154.5 lbs-ft (pretty close to what I calculated above, BTW). Plugging that value and your corrected RPM into the equation I provide above:
  
  HP = (Torque*RPM)/5252, so (155*4000)/5252 = 118 hp.
  
  Virtually identically to the horsepower shown on the plot at 4000 RPM, so obviously G-Tech have improved their computer model in that RPM range.

  
  
  AFAIK Gtech never made an incorrect calculation in TQ and HP relation. Gtech senses the vehicle's g force via its three accelerometers and then calculates torque based on RPM, vehicle weight, and a few other data. Gtech then draws out the HP curve based on the simple formula you posted. Again, there weren't problems with TQ vs. HP relation you may have previously thought. This may be why you thought comparing my 1.6 IDI to a 1.9 TDI (both have very different curves) to calculate my 100whp (based on moving my 164lb-ft from 4,000 RPM to 2,500 RPM according to the TDI's curve) were justified - or whatever it is I have no idea.
  
  Since the Gtech readings are consistent, the difference between the consistent net horsepower of a stock 1.6TD and the consistent net horsepower of my present 1.6TD leads me to believe 150whp is more than plausible. The comparison against a VR6 made it easier too.
  
  If you still believe about the Gtech throwing a fit, deforming torque curves or whatnot, then take a look at few of fspGTD's Gtech plots he posted a while ago. The curves are very comparible to the factory curves (just like mine in my Gtech #2 post), except with slightly lower % power/torque figures that are normal.