Author Topic: turbo question (Read 4696 times)

hillfolk'r · « **on:** December 11, 2005, 01:19:23 pm »

ok im using (or want to use) my garret t3 turbo from my 86 td on my alh tdi that im building,,its gonna be mech. pump,w/12mm plunger,race 520 nozzles,,,,,,my ?? is,,,does anyone know some numbers for a new comp housing and wheel?? im worried i wont have enough air,,cause iused to let this turbo go closed wastegate on the 1.6,,and it ran great,35+psi ,,if i canfind a bigger wheeland housing,,i can rebuild the turbo at work,we have a good turbo guy,whoknows turbos,,but cant help with upgrades,,if i have some part#s then he canwork with it, i like the garret,seems to have a better top end rush than the kkk on my 84td,,,iswapped the kkk of my 84 and put the garret on,and was much happier,,what uguys think?

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RabbitGTDguy · « **Reply #1 on:** December 11, 2005, 04:21:39 pm »

What exactly do you need? Different compressor wheels? Or trim housing part numbers? Ideally, I think your compressor side is fine. There may be merit though in upgrading the turbine side... a little bit more lag in the bottom but with your fuel/air combination, i doubt you'd notice the increase from .38 (your T3's hot side) vs. going up to say a .48 hot side. That means changing your housing altogether and if your planning on using the 1.6TD exhaust manifold it also means you'd have to change that to elimnate the keystone style flange or make an adaptor for adapting it. I'm using a T3 on my application as well. staying with the .42 cold side and a .48 hot side. Couple reasons...its tuned to make power and be efficient within the rpm range of the diesel motor and will provide some extra umph on the top end and better breathing thanks to the larger .48 hot side vs. using the smaller 1.6TD's stock hot side. Not looking for more than 30 psi...but...we'll see. The turbo could support it. I'm running similar modifications but with a DI specific 12mm mech pump, backset turbo and manifold as well as a modified plenum style intake manifold. Injectors are still up in the area... probably not Race 520's...too much smoke...efficiently, and power wise...i think I'll end up at PP520's or PP764's....

Joe

hillfolk'r · « **Reply #2 on:** December 12, 2005, 11:49:52 pm »

yea,,iwas figuring on compressor side upgrades,,with the 520's ill probably need it,,i used to let the 1.6 run closed wastegate cause it flew,,15.79@ waterfest,,,,but i figure that the turbo willget angry after a few 100k of close to40psi(of course not all the time),,,,,the way i see it ,,,if im spinning turbo the same speed,but have "more" compressor,,then ill have more air,,,right???,,then i wont have to go 40 psi all the time,but im a nut,soi mayanyways soidont see what making the exhaust side larger,,i think thats about right,,so doyou have anyideas on bigger wheels and housings???ihave all the part # s sitting right here if you need them,,,thanks for any help man,,,,,,,,,toolate on the injectors,,ialready got the nozzles in

i like smoke anyways,keeps the 'gaters away

RabbitGTDguy · « **Reply #3 on:** December 13, 2005, 06:40:56 am »

The larger the turbo on this type of motor, the farther up the RPM band your going to move the power band. So upgrading the compressor side too much, or with the wrong trim, you'll increase your spool up time and how hard the motor as to work to get it moving. .42 on the cold side, compressor side IMO is pretty good for the diesels...it'll do 25psi+ through relatively all the power range you can want. Merits on the hot side upgrade to .48 are increased efficiency in those higher RPM's where we all are tending to try and find extra power these days.

hillfolk'r · « **Reply #4 on:** December 13, 2005, 07:30:08 pm »

i guess i dont see how a bigger exh. side will give more power,with all the other stuff staying the same,i dont see how the turbo can spin same speed,with larger exh side,,,when all things stay the same on the int. side,,,iknow it aint the same,,but exh side upgrades for the "b",, usually give you a smaller housing,,,so i see w/a smaller exhaust side,turbospeed goes up,,,they are less laggy,and power is sweet,ive done a few atwork,,,i bet the b as stock,has too big an exh side,,,,,so im thinkin that if i go larger on exhaust,,itllslow down the turbo,meaning less boost,,,,,,,,i will let it go over 25 psi,or whatever itll top out at,,i figured a little larger in intake side should be ok,,just not monster huge,,not too worried about lag, just need more air,,,gonna have to look into this hybrid deal maybe

RabbitGTDguy · « **Reply #5 on:** December 13, 2005, 07:40:02 pm »

Your partially right...partially wrong...

Where do you want the power? The hot side will help determine this. You can do whatever you want for the compressor side, alot of options there but if you want to broaden the rpm range at which boost is most efficient a larger hot side will allow things to "breath" better in the higher rpms... .48 for a diesel hot side would just be about perfect. Look at your Audi IDI TD's as well as Mercedes and the like... various 5 and 6 cyl models all use the .48 hot side. the smaller hot side with the larger compressor wheel WILL run out of steam unless you just want your power right around 2k-3.5k i imagine. .48 is only a step up, not huge. I imagine the difference in spool up time on a TDI motor, especially a built one is HARDLY even noticeable. You haven't said what kind of trim and compressor wheel you want to run on your cold side but basic forced induction theory on compressor wheel and trim housing upgrades notes that these things must be done to benefit each other and work with each other in correlation.
So what size trim and compressor wheel were you thinking?
Where do you want max boost...and efficiently?

From the books...
Bell's Book
basic turbine selection... "consider basic turbine size a measure of the turbines ability to gernerate the shaft power required to drive the compressor at the flow rates desired. Larger turbines, thereforre, gernerally offer higher power outputs than smaller turbines..."

Flow capacity is a major concern here... so you want to run 30psi or so on a smaller turbine...with the smaller turbine you also get less flow capability because of the smaller turbines exducer bore which is relative to its hot side A/R

Also from bell's book...
"It is of further value to note that a larger R will effectively give the turbine shaft greater torque with which to drive the compressor wheel. The same force (exhaust gas) applied with a greater level arm (R) puts more torque into the shaft...

In short... if this motor is being built the way you say it is then it will have great flow capabilities...not to mention, the TDI in general will flow better than an IDI unit for which the .38 hot side A/R of the orginal T3 was matched too. So..you increase the hot side A/R to compensate for your larger cold side A/R that you want to do as well, this increases the efficiency of the unit but making less work in the higher RPM's by allowing the size of the wheel, which is only slightly larger to translate the power/shaft torque needed to keep the compressor side spinning efficiently and through a broader range of RPM thanks to the benefit of the larger turbine wheel and a larger, more efficiently flowing exducer bore that is more evenly matched with the compressor side as well. The lag on a .48 I think really will be nominal...i'll tell you in the spring for sure.
Conversely, the smaller turbine, with a larger compressor side (not sure what your thinking... but in this case, above say .48 max) is going to make the turbine side have to do alot more work with alot less output and efficency at the top when you want it to be boost efficiently instead of choking and running out of steam.

Don't know if thats any better...but its my shot..

Joe

hillfolk'r · « **Reply #6 on:** December 14, 2005, 10:55:08 pm »

well,it seemed onthe 1.6,,,,the orig kkkturbo seemed to have great low end/midrange,fell flat up top,,,iswapped the garret on it,and low end was ok but got stronger in mid,and had great top end rush,,,,,,yea i been thinkinthat now ona 1.9 is even more stress ,,hell with it,,ill probablyleave it alone. for now,intake now has alot of porting,and the intake inlet?is cut down,,like a old idi,yaknow???nice for porting in theretoo,,the stock1.6 turboexhaust manifold canhave some major cleanup in it,,the cast in bulges to clear the turbo thru bolts canbe reallyknocked down,and blended,,,head was cleaned up in the ports,rough edges,etc,,exhaust ports chamfered at end,to eliminate steptomanifold,,the ports in the manifolds are waybigger thanhead ,,,this freakin sapcebar sucks,,im sorry,,,,,id like anidea of hp/tq. that this thing will put out though,,,,,,hope its a good sleeper,the rabbit w/tdi :twisted:

therabbittree · « **Reply #7 on:** December 18, 2005, 07:16:19 pm »

joe i think blake and i want similar singleturbo hes saying he wants to keep the stock 1.6L hot side and swap a larger compressor on to keep the same lag of the 1.6 but more boost and cooler.. i think twins will work work also.. i personsally don't really really get the a/r ratios ..asl long as i can get 40psi and not get too much heat ..thats cool with me and blak i beleive..we are both shooting for around 40 psi max on a singel turbo ..i may do twins but blakes going single ..and to not blow our headgaskets...or turbos...to heck with the a/r map ... at least yet..and not sissy tdi tea party 20 psi boost #.s we want double that..tune it like acummins b..
merry christmas
deo
\x/ Hillfolk!

RabbitGTDguy · « **Reply #8 on:** December 18, 2005, 10:35:54 pm »

To each is own

The A/R maps and compressor/turbine sizes, etc. specifically balance each other out to make the most power, most efficiently relative to the size of the motor and peak power output. We'll see what happens.

Good luck!
I'll be going for the 30's with the upgraded turbine side and doubt the upgrade will even be noticeable... spring will tell!

Merry Christmas as well!

Joe

therabbittree · « **Reply #9 on:** December 19, 2005, 08:07:36 am »

yeah its just a real pain in the ass to get a turbo wthat the map is still good at 35-40 psi with the same size turbine housing or lag in spool as the stock 1.6l td..or close. heck we know the 35 psi out of thekkk24 is WAY way off the map and not good ..so if they could get a compressore housing that was a hybrid and way bigger that would help..i think... badsically my own opinion is to getteh best of both lag and cool in the map boost you need to do a set of twin turbos or supercharger feeding a large turbo.
Thanks
deo
Joe when did you get all techno on us???

merry christmas
ps i left a message on your phone..i broke my 1.6L td head tightening the injectors in with a hand racket..yep you heard right broke the damn injector boss right off and cracked two other bosses ...never heard of that before..so im f'ed.. swapping out the 1.6L I just fully rebuilt argharghargh with a good running '98 tdi engine i have here 150k miles on it doing the 12mm pump on it sucks big time ..argah...any how the lifted bunny truck looks really bad ass i'll have to take apicture soon..
Thanks
deo

RabbitGTDguy · « **Reply #10 on:** December 19, 2005, 09:49:41 am »

deo...

Not really technical... nor conservative...just want to try and help match the optimal setup for optimal power. Nothing really too complicated in that

My thing is again... and actually to mentioned the K24 being off the map above 30, etc. You'd be hard pressed to find any T3 or KKK of the relative size that will work the best at that PSI and still be efficient. Now, a compound setup...thats a different story. Like I said...to each his own

Still doing plenty of seat of the pants mods, etc... but when it comes to turbo selection, even before with the IDI TD I can't help but to make the best choices to save all the time and $$$ invested in its internals...

Just in case you guys are interested. The 300D Mercedes turbo that I'm going to run on the TDI, I also ran on the IDI TD for a little while prior to its removal and being sold. I didn't notice the lag whatsoever and top end breathing/response was much better. If you have enough fuel to move it in the lower portion, then...it'll be fun. It was very happy at 25psi just during testing...

Have fun!

Joe

hillfolk'r · « **Reply #11 on:** December 19, 2005, 09:46:26 pm »

im not planning on revving it to the moon,,use a diesel for torque,,,isnt stock redline on a tdi like 47-4800??,soi dont plan on revs,,imwilling to have a piggy low end,as long as it starts hittin in mid to top,,,im not conservitive,,,,,,,,deo remember the gasser 79 engine(the little 1451)

?yea it felt like a diesel till 4500,then someone turned on the switch,and it flew to 7500,g grind,basic stuff,,,,but i aint lookin for a ride for granny,im lookin for nut,,i figured like deo said,,more air,for cooler temps,dont haveta boost as much,,,trans is "resealed+bushed",,waitin on the peloquin 80% kit,,gotta installcam,set engine on ground to mark the f.w. for tdc,,,i made a piston stop from a old glow plug,and threaded it for a 6mm stud,,,cool tool,,,another cool tool is a "tranny chunk"cut from an old trans,i use the top 2 bolts section of it,,,,,,this is soyou dont haveto install a trans to do timing belt stuff,,,,,,,wonder if i can get my fuel guage to work on one of those "universal" senders they use in fuel cells,gotta ditch stock leaky tank,,, :cry: