VINCE

iTrader: (1)

I did a search and I could not find any valid research. How do they stand up to each other? Is there a max turbo size limit for either? Will one require more boost to make the same horsepower if they were tested on the same motor? Which will spool faster?

V8_DSM_V8again

First off T3/T4 denotes the combination parts from garret T3 and T4 series turbos..

Typically its a T3 turbine wheel and a T3 turbine housing assembled with a T4 compressor section.. The turbine housing flange is the flange you are refering to.. There is a degree of overlap between a t3 and t4 series turbine housings depending on their A/R ratio.. A=Area and R=Radius..

As for T3 vs T4 its kind of like a small (T3) vs a big block engine series... You can sometimes get the same displacement out of either but the biggest displacement possible will come from the big block.

Which all have been superceeded by the new GT stuff..

Spool depends mostly on the A/R of the turbine housing, which turbine wheel and engine volumetric efficiency and engine displacement..

This is a huge subject and to explain it all would consume all day.. There are entire books written just on turbocharger sizing and selection....

Go here....
http://www.forcedinductions.com/help.htm

smokinHawk

iTrader: (48)

would a t3 exhaust housing be to small for a 346 (using two turbos)? or is it just barely big enough

V8_DSM_V8again

It depends on the A/R...

I still need to know your desired RPM range and the amount of hp you want..

If you want a quickspool setup go small.. Wanna be the dyno and track king go big..

A .82 t3 turbine housing will probably be great for street and strip twins.. Strip only twins or hot street I would recomend a T4 series turbine housing.

For my twin turbo 4wd trail truck all my engine analyzer and turbocalculator math says .63 will be perfect for what I want... I want the 3200 rpm tq peak and am willing to live with fading top end... Its going to spool as quick as an standard production audi turbo...

http://www.hotrod.com/techarticles/e...rbo/index.html

Good info for newbies.

93formto98T/A

iTrader: (28)

For example I know the CAS twin turbo kit came with a pair of t3 turbos and have seen numbers over 700rwhp with those so they do work but are not optimal for higher power apps. I chose to go with 2 t4 61s good for 1400hp.

V8_DSM_V8again

You could probably do that or very close to it with T61 compressors on a t3 turbine with a .82 A/R

On a ported DOHC 2.0 with a .63 A/R T3 turbine side and a GT40 56 trim compressor side it wont spool untill 4000 with a standard bearing turbo....

However two of those on a 6.0 each getting their own 3.0 to play with hits 25psi around 2400-2600....

It depends on alot of things..

30th t/a

iTrader: (51)

i have a CAS kit so thats interesting to me. do you know if the person who made over 700rwhp is a member of this site? i know A DEE O made 681 on straight 93 with his t44s but he had a p trim turbine wheel. i wonder how much that would have helped him over the stock turbine wheel.

93formto98T/A

iTrader: (28)

yea, I know of A DEE O cause I nearly bought his kit before talking to GMR about a custom twin kit. I can't veryify that anyone has made over 700 but have only heard that guys were maxing them out at over 700.

eviltwins

Speaking from personal experience and not just trying to guess out of thin air like you, you're on crack if you think twin SC61's are going to make 25 psi at 2400-2600 RPM's on a ~360 inch motor. Ask danimal95 on here how his 61mm turbos spool up on his 347, it sure isn't 2500 RPM's.

XJGPN

I'm assuming your being sarcastic or something? But for people who are actually serious about this question... for comparison, the Incon kit used T25/T28 flanged turbos (If I remember correctly) which is even smaller than T3's. The CAS used T3 flanges (as has already been mentioned). As has been said before, a twin T3 hybrid setup could get you a good deal of power, but you start getting a lot of backpressure at higher HP levels. The only reason to go with twin T3 flanges over twin T4 flanges would be space constraints, as you will have a much better selection of useable turbine housings with the twin T4 setup.

V8_DSM_V8again

What turbine housing does he have... If its a T4 I dont doubt it spools later... Which turbine wheel...?

Trust me.. The compressor wheel is only half of the equation...

The 6.0 spool spec I quoted is using the exact same turbine housing and wheel as on the 2.0 on EAPro .. It is also a mildly cammmed engine with great heads (flowbench data).. The cam helps lower the spool point..

I know for a fact because I have bolted a PTE SCM61 to more than one built mitsubishi engine.. It will spool at 4,000 rpm like clockwork on a 2.0.

What? You dont think trying to put 1.5 times the flow thru the same turbine housing will lower the spool point..

7th grade algebra for you..

1.5 * X = 4000

X=4000/1.5

X= 2666

The 2400 to 2600 range depends on which of the handfull of cams I enter in the software.. EVO exhaust valve opening duration and timing effect spool alot.

Incidentally the simulation version of my mitsubish engine and turbo system was dead on.. Spools at 4k just like the real deal.. It takes forever to actually enter in all the exact specs for every little thing. But if you are accurate with your specs it will be an accurate simulation.

Hmm I'll guess I'll have to use my copy of corky bells book maximum boost as toilet paper since you know everything he does'nt..

I will also have to tell Ken D that all his record breaking turbo small blocks are wrong because he uses engine analyzer pro software..

Sorry dude I'm right and he is using a larger full fleged T4 turbine side hence more lag but probably more power 5k and up...

eviltwins

Did you just try and like smite me with some desktop dyno/engine analyzer pro info? lol!

danimal's car is running .70 A/R T4 tang housings with P-trim exhaust wheels. There's obviously going to be a difference in lag between the two housings and wheels, but if you look at danimals dyno sheet he's clearly not getting full boost till the ~4500 RPM range. I don't care how magical of a combination it is, going from a .70 A/R p-trim T4 setup to a .82 A/R Stage V T3 setup with the same compressor side is NOT going to knock out 2000 RPM's worth of lag on a setup.

Here's a 2.0/SCM61 dyno That doesn't really seem to be spooling it "like clockwork at 4000 RPM's" if it's not quite making 250 ft-lbs of torque at that point and the torque curve hasn't even started the sharp rise from the turbo spooling yet.

Good SCM61 impressions thread For those too lazy to read:

There's some 7th grade algebra for you, but maybe you just had a miracle SC61 that PTE installed ball bearings into long before they were available to the public, you got a super prototype that lets it spool up 500-700 RPM's faster than everyone else Gotta love how in the first sentence of your post you tout how much camshaft changes will effect turbo spool up, then a few lines later you make a direct comparison between spool up and displacement. A+ champ.

Browse around Supra forums, if these SC61/GT35 turbos were such a magic bullet like you claim them to be, I bet a lot more of them would be posting dyno graphs and posts of amazement at their 2500 RPM spool, not ~3500 RPM spool like they are actually seeing with .68 A/R hot sides.

qqwqeqwrqwqtq

Fwiw, Danimal95's car hits 20psi boost at around 4,800. GT61, standard bearing,p-trim .7 a/r tang.

Those same turbos with .69 a/r on center housings made 20psi at 4500 on my 359ci LT1.

I now have dual ball bearing GT61's with p-trim exhaust, and welded/ported on center housings. Now hits 20psi at 4,200.

I don't think twin SC61's on 360ci would hit 25psi by 2500 without nitrous, but I can't say that I've tried it.

V8_DSM_V8again

Then why do I spool at 4k in first gear and even lower going thru the gearbox as the ratios get taller?

Why? because when you run a .63 AR T3 & T350 wheel like what I was actually talking about it spools MUCH lower.. That is the combo I was talking about..

Lets forget Engine Analyzer Pro even despite the fact that it makes desktop dyno look like a atari game.

HMM we have two real world running cars...

I have 122 cu inches spooling it at 4000 rpm vs 173 cu inches spooling at 4500 rpm...

So he gets 50 more inches displacement and 500 rpm more lag...

Sounds like a much more open exhaust side to me.. He probably has lower exhaust manifold pressures at upper rpms however. The T4 turbine wheel and its integral shaft are also heavier... So they take more energy to get going.. Then there is the issue of the larger thrust bearing area.. Longer lasting but more friction...


Thats funny I have over 2k posts on that site.. I know of many other people on there that hit boost at the same RPM as me...

I have seen better SCM61 dynos too... I also see one on my car and one next to some LS1 parts and a 16g turbo. Maybe I wont see the 16g on the shelf but I'll see two SCM61's. and more LS1 parts

Hey look Jose is on there talking up the SC61...
http://dsmtuner.com/forums/showthread.php?p=1117077

A better link
http://dsmtuner.com/forums/showthrea...ht=SCM61+spool

I have all the right mods and ran smaller upgrades before.. Heh I maxed out a 50trim... Incidently AWHP is HP put down to a AWD dyno..

Hey look jump up .4 more liters in displacement and the spool point drops 500 rpm to 3500... At that rate a 3.0 (1/2 of a 6.0) would be ~2750.... HMMM I'm begining to find third partys to prove my point...



Wow what useless banter...

Gotta love how you misquote every one of my specs.. Also I got it in the ballpark via with a crude estimate via displacement changes. THEN I mention there were different RPMs it happened at based on which comp grind I put in the program.. Maybe I just understand and size things right and thats why it does'nt lag as much? The compressor wheel on that baby is pretty magical.. I just wish more people put more thought into matching it with a turbine side..

Although the other configuration is "right" for peak power at the expense of spool. Its only "right" if it does what YOU planned it to do.

Yes its just too bad that they run a .68 T4and not a .63 T3 turbine setup like what I am talking about..

V8_DSM_V8again

Its the whole T4 turbine housing .69 and p-trim exhaust wheel as opposed to the T3 pieces that makes the difference...

http://www.dsmtuners.com/forums/show...oto=nextoldest
So you have a turbine housing targeted for higher rpm and a wheel more targeted for higher RPM...

Yours are also good to about 680hp each on gas as opposed to 630hp..

VINCE

iTrader: (1)

Lets keep this civil.. What setup would work well on a 408ci low compression motor and have the potential to produce CRAZY horsepower if pushed? I am talking about a twin setup..

V8_DSM_V8again

In that case full T4 turbine housings...

Like INTMD8's rig... not identical but very much the same.

Twin PTE GT35R's Potential for 680 per cylinder bank about 1300 hp..

The GT40 56 trim wheel is just waking up about 25psi...

Beyond that its stuff probably only Ken D, Keith urban, Mike moran etc should be playing with.. Like maybe 2 GT42R turbos on a twin scroll AKA T4 divided turbine housing. You would need a 4 into 2 exhaust manifold with two paired cylinders going into their own half of the turbine housing.. It helps make more power and spool earlier.. Ever see a 4-2-1 header.. Well the turbo takes care of the last the 2-1 part... Two GT42Rs is like 2200hp.. There are alot of other things that have to be done just to keep it together let alone actually get close to that HP...

Just one turbo in the GT42R ballpark on a 2.0 in the right hands is enough to shatter records... 100 shot of N20 down low is what makes it actually work on a 2.0... You wont need that..

http://www.shepracing.com

smokinHawk

iTrader: (48)

not being sarcastic just curious, i knew the incon's housing were small but wasnt sure exactly what they compare to.
didnt know the CAS were T3's some reason i always thought they were t4's

XJGPN

Sorry about the "sarcastic" comment... I respect your knowledge of turbo stuff and figured you were joking or something. I'm working from memory now, but I remember being perplexed when everyone was talking about how they were SOL with their incon setups because they didn't have their CHRA's and concerns over not being able to go big enough on the turbo and I kept thinking "why not just get another T3/T4 hybrid and install it... started looking into it and incon went with pretty impressive turbos built on a T28 flanged turbine housing. It takes some crazy expensive T28 flanged turbos to be able to feed an LS1, since they are usually only used as a single turbo on sub 2.0 liter japanese cars. The CAS manifolds definitely use a T3 flange because the turbos they use had the integral wastegate (although it was eliminated, and the port was plumbed to an external wastegate).
As seen here:


Although, I saw an earlier prototype that used non-integral wastegates with their own feed coming down from the middle of the log:


As for your original question about if T3/T4 hybrids could feed an LS1... based purely on my opinion and not using any hard numbers, I'd say that if you plan on never exceeding roughly 750 hp you can achieve it with hybrids just as easily as with a straight T4. While there is no reason you couldn't feed 1000 hp with twin hybrids, your backpressure really would be off the charts, and at that level, you really are going to want to have a more efficient setup just because all that backpressure is really going to cause a lot of durability issues.

smokinHawk

iTrader: (48)

ya it seems like those can only get to 700rwhp before they run out. I realy dont know to much about t3/4 turbos, just always stuck to the T4's and mostly in single applications.
brain kicked back on , dont know why i thought they were t4's specially with the intergrated wastegate, though i never paid attention to the pic with the external gate, but changing plugs on those things look as scary as everyone says.