if the td04 makes no power past 16psi, then why do all the fastest 2l subies (ie, those in the 12s) run in the 20psi range?

just because YOU (or the mystery supertuner) haven't gotten more power out of it past 16psi doesn't mean its not there. i myself pulled 4.4maf volts from a td04 running 20psi over a year and a half ago.

 

A WRX running 12s with the stock turbo? 20PSI through a turbo with 290cfm flow rate? Not for more than a few weekends...

Here's an interesting writeup on the strengths and limitations of the IHI/TD04 series of turbos with some very revealing flow maps. They are for a 3.0l engine with a 7500RPM redline, so you'd have to scale the results back about 100cfm for the 2.0l/700rpm redline of the stock WRX motor.

http://www.stealth316.com/2-3s-compflowmaps.htm

 

dude...

the more you talk the more it belies how much you do not understand.

20psi and 290cfm, first of all, have NOTHING to do with one another. the first is a pressure, the second, a volumetric flow rate.

second, the oem wrx td04 turbo has a 13t compressor. its map can be seen below:



as we can see from this map the island of highest efficiency extends well into the mid 2.6 pressure ratio area. that means a manifold relative pressure of 1.6bar, or 23+ psi. so the turbo IS efficient at that boost level.

now, back to volumetric flow rate... according to hotrod/larry's turbo comparison chart, the td04/13t is actually good for 390cfm, not 290. http://forums.nasioc.com/forums/show...69&postcount=3

all of this "book stuff" notwithstanding, the fact of the matter is that LOTS of people have gone VERY fast with the oem wrx turbo:

OppositeLock 1.755 60'
12.682 @ 107.63 Old Bridge Township Raceway Park PA. 4/21/06

Quicktime 1.742 60'
12.78@106.62 Atco 3/23/04

O Stylee 1.739 60'
12.906@104.15 Maryland Intl Raceway 9/20/04

Amazake 1.770 60'
12.941@104.31 New England Dragway 5/19/05

Oppositelock 1.822 60'
12.942@105.56 Old Bridge Township Raceway Park 3/10/06

Gadiel 3/20/03
12.955@102.25 Puerto Rico

IWRXIT 1.82 60'
12.967@105.65 Bremerton Raceway Wa 4/9/04

Quick scooby 1.86 60'
12.97@103.61 Temple Academy Dragway Tx 2/07/03

Carlo 1.843 60'
12.981@107.00 Atco 5/31/2003

12.9$500rex 1.781 60'
12.989 @ 102.99 US 41 Dragway 12/05/04

Hassassin 1.784 60'
12.9@102 Etown 11/15/02

some of these trap speeds indicate power levels in the area of 300whp. this is impossible on paper.

longevity isn't the point here. the point is whether or not the turbo can make power past 16psi... and i am telling you it can.

 

You need high octane to run those times/high boost levels. Or water/alchohol injection.

 

You are talking about cars that have changed out almost everything EXCEPT the turbo, and are running race gas to boot. FMICs, stripped interiors, 800cc injectors, etc. I'm talking about 91 octane on stock internals. VERY different situations.

With 91 octane and stock injectors/fuel pump, the EJ20 doesn't produce enough exhaust to push the turbo to anywhere near 25psi; it craps out around 18 and stops making power at 16.5, just like I said. That is why so many people on this board (as well as the tuners at Dyno-Comp, who tuned my WRX) switch to a VF34 or VF22 once you need to get past 250whp. Certainly, if you were looking for a drag car only and had all the supporting mods you could make power out of almost any turbo. For those of us not building purpose-built racers, the TD04 has limited utility.

 

the fact of the matter is that you guys don't know what you're talking about.

the fact of the matter is quicktime's run was on 93 octane http://forums.nasioc.com/forums/show...9&postcount=29

the fact of the matter is that I PERSONALLY have run over 20psi with a td04 on 93 octane gas. no adi, no race gas, no nitrous, no tricks, stock tmic, reasonable timing (ie 15* torque peak) and it pulled like hell.

it is all in the tune.

i supplied a compressor map. it demonstrates in black and white that the turbo is efficient at high pressure ratios. if you don't know how to read efficiency from a compressor map, you should do some research.

even if you don't believe me, which it seems you do not, do you believe someone like hotrod/larry? http://forums.nasioc.com/forums/show...5&postcount=14

in the meantime, keep repeating everything you hear, because that's the way it's done on the internet, isn't it? just remember some of us walk the walk.

 

Running 18 psi on my stock turbo vs the normal 16 psi, i was able to make an additional 10 peak hp and about 20 additional ft/lbs of torque. This was with a stock TMIC and on 93 octane gas. Boost tapered to around 14psi by redline.

I've since retired my trusty TD04 and moved on to a super 16g. It's currently pushing 23-24 psi and making some fantastic power. I found that the stock IC couldn't handle more than 20 psi on it, so I upgraded to a larger TMIC. It's been fine since.


Mike

 

Flame thrower

Please all you guys keep thinking "flame thrower".
OMG 20psi your **** will blow up.

TMS

 

This proves my point exactly. You added two full PSI of boost and got only 10hp -- yet I was able to add over 70hp to my 02 WRX by moving peak boost from 14.7psi to 16.1psi. Once you push past 16 you get heavily diminished returns. Did you measure your EGTs? What was your degree of knock correction? Of timing advance? Did you ever run this setup with 91 octane? 18 or 20 PSI with the stock intercooler is just asking for 1600-degree EGTs, knock and pulled timing.

Ride5000, you are exactly right -- I don't believe you. There has to be a reason (besides making money) that Cobb, Vishnu, Dyno-Comp, Turbonetics and many other well-respected tuners all advise moving to a bigger turbo past 16psi or at least doing a complete port and polish on the stock turbo. 20psi? Sure, if you like an engine rebuild four times a year. Go to the Aftermarket Turbo forum and tell everyone how they are wasting their money on those 16gs, VF22 and VF34s, I'm sure they will be sympathetic.

 

first of all, you don't tune anything. you have no idea what it entails.

second of all, was manifold pressure the ONLY thing that was changed?

not that you would know the answer, since you don't tune anything.

i will tell you the answer... you CANNOT net 70hp from ONLY adding 2psi of manifold pressure to a wrx and changing nothing else. as in, it is IMPOSSIBLE, no matter who the tuner is, or what the turbo is.

i laugh at 1600* egts. to make power you will ALWAYS exceed 1600* without ADI. you don't know that because you don't tune anything.

that's funny, because i ran a td04 at 20psi for tens of thousands of miles, and the turbo came of with no excessive shaft play, and the engine comp tested @ 165psi all around.

"tuners" don't push the envelope with other people's cars. they push it with their OWN cars, just as i have done with mine. the people who do believe me know i am not content to regurgitate someone else's "facts." my car has never been rebuilt, is 3+ years old, has 50k miles on it, was wrenched on and tuned exclusively by me, and runs 12s at 105+ mph with 100* ambient air temps. i speak from EXPERIENCE.

only a complete idiot would equate boost pressure to mass air flow, even when being shown the difference, over and over again. can you be any more obtuse?

pressure is not flow. flow is not pressure. the units of measurement are different.

20psi on a td04 is not 20psi on an 18g is not 20psi on a gt35r. same pressure, different flows.

is any of this sinking in yet?

 

^^^^

OMG you run over 1600*. Your valves are going to melt.
NO it will be a piston first.
NO your turbo will assplode.

HAHAHAHAHAHAHAHAHA
Ken why are you still here? No one listens because you don't know anything.

TMS

 

Yes- 10 hp peak but boost tapers. That 20 ft/lbs was gained in the midrange.

As far as wasting money on a 16g- I disagree. I'm running one now. And I'm pushing 20+ psi on it. And I am seeing MAF voltage of 4.62 at the top of 3rd gear. That's something that is in the range of an STi with exhaust/tune. On the TD04, I saw some 4.4s. This is making quite a bit more power.

 

[QUOTE=ride5000]that's funny, because i ran a td04 at 20psi for tens of thousands of miles, and the turbo came of with no excessive shaft play, and the engine comp tested @ 165psi all around.
[\QUOTE]

Yeah, but you drive like a grandma.....

 

...yeah. Since you do tune engines, I had figured you could fill in the blanks for this one. No one turns up just manifold pressure and nothing else, unless they plan to blow the engine through the hood in some sort of Mythbusters pyrotechnics. No, we added a turboback exhaust and changed the a/f mixture and curve, the spark timing and a few other variables. My point is that getting the car to the peak efficiency of the TD04 only required a tiny amount of boost change for huge gains, but past 16psi the gains slow down radically -- exactly the experience of Rich Gonzales from Dyno-Comp and many other experienced people I have talked to.

Your tendency toward personal attacks makes me despair of gaining anything useful out of this discussion, but I'll soldier on. 1600+ degrees is half the melting point of mild steel; you can push it to almost 2000 before you get any change in actual strength. But as a tuner, you must understand that the hotter your EGTs, the more you are heating the "cold" side of your turbo (ceramic coating or not) and the hotter your manifold temps rise. Hot manifold temps = detonation. ZERO amount of knock is tolerable in my book.

Since you speak for all tuners of cars, I'll have to take your word for it. I'm trying to reconcile the vast difference between what you are saying here and the credible, factual and insightful opinions on this topic that I have read on this board, on others like it and in personal discussions with mechanics and full-time tuners.


This is actually the first time such an issue has even entered the discussion, and you're the one who mentioned it. We're discussing the TD04, and nothing else. My point is, and has been from the beginning, that the TD04 is poorly suited to high-boost applications because of its restrictive laminar flow which causes drag on the vanes, high manifold temps and detonation at high PSI. The flow diagram you posted isn't relevant, because while it does show efficient boost to 26psi, the stock 02 WRX motor doesn't generate the volume or velocity of exhaust needed to actually drive it to 26psi without leaving the wastegate shut forever and delivering superheated air. Hooked up to a V8 5000cc turbo diesel, that TD04 might be able to hold 30psi to redline -- but it is hooked up to a 1996cc boxer engine with a 7000rpm redline.

I guess the concept I can't get my head around here is why someone would boost the TD04 to 20psi when a VF34 at 18psi or a 16g at 17psi would be producing the same or more power, with less risk of detonation and less need for exotic fuel mixtures or "envelope pushing." Sure, bragging rights alone is a good argument for this, as is cheapness (burn out a TD04, throw it out, get another for $250). If you've had such success doing so, congratulations and good luck to you in the future. However, if the best you have to offer is attempts to bully your way through the discussion with personal attacks, you'll have to forgive me for remaining skeptical. All you've managed to do so far is attract some hecklers, for some odd reason.

 

I agree 100%. Unless someone is trying to "prove a point" there is no need to stress the motor like that...