so, the big 16g.

[Herbal]

aight, went to buy a 16g from a local guy. went there specifically to see a 16g that needed rebuilding. well that one was too far gone IMO. Then he produces another 16g, this one looks much better. some play, sure, maybe a tiny bit of contact (clean edges on the compressor blades but not smeared or chipped) but rebuildable. im on a budget, some crap is expected.

get home a minute ago, check the part numbers, i got one of the seemingly hated big ones(part no. ending in 420). now, the hotside that was on it was all cracked to shit, so i passed on it for a cut off the price. the thought occured to me that i have a nicely ported 6cm housing on my blown out 14b... hmmm.

so, the big issue with the big16g's seems to be that while they can flow okay, they spool slowly due to a fat compressor. what would i get with the 6cm housing attached to it? im betting id get some boost creep, but i dunno.

beyond that issue (which could easily be fixed by finding a evo3 hotside) how bad IS the spool on a b16g, and would it be detrimental to fwd? i've heard a lil lag isnt so bad for fwd. btw this is all happening under the hood of a colt so it's a pretty light car off the bat, and my current power goals fall in the region of "mild". i want to run 12's but it isnt crucial, pretty much looking for a grin on my face, no attention from cops, lightweight racing/aggressive street driving, and 4 cyl gas mileage. the original plan called for a small 16g, an efficient fmic/ic piping,550's and the parts i already have which include a straight 2.5in exhaust, safc,wb255,2g man. all that's changed is a big 16g instead of the small, a step down for sure but im not sure it would really hurt me running less then 25psi.

 

[the_mork]

I would not suggest putting a 6cm hotside on that turbo. Even a 14b can benefit significantly from moving to a 7cm hotside.

I would suggest going with a 7cm hotside and running what you've got.

The problem with the b16g isn't that it spools slowly so much that it spools slower than the sm16g while barely flowing more and about at the same speed as the evo3 16g which flows a fair amount more air. It still spools pretty quick and would be a fine turbo to run.

 

[joe sobo]

why is the "420 " the seemingly hated turbo? i just picked one up for 130.00 shipped. it also is the 1420 part number. what the spool-up compared to the e316g and the s16g?

 

[JusMX141]

why is the "420 " the seemingly hated turbo? i just picked one up for 130.00 shipped. it also is the 1420 part number. what the spool-up compared to the e316g and the s16g?

Beats me. These turbos have made lots of power over the years.

The compressor wheel measurements are almost identical to the Evo III 16G (.010" smaller on the inducer) - the Evo III compressor has lighter and thinner blades for quicker spool (100-200rpms MAX).

One benefit of a Big 16G is you generally don't hear the boost creep issues which seem to plague the Evo III. This is because of the different turbine housing, I'm sure.

I ran a Big 16G on my FWD TSi for years and loved it. Couldn't imagine how an Evo III 16G would be better unless it was free or I was planning on running lots of boost to make the better-flowing turbine housing more useful.

 

[Yngvar]

I don't know what your taking about when it comes to lag on a big 16g they spool really quick. I think my friends 18g spools fast compared to my turbo. His 16g car spools at idle almost.

 

[joe sobo]

Beats me. These turbos have made lots of power over the years.

The compressor wheel measurements are almost identical to the Evo III 16G (.010" smaller on the inducer) - the Evo III compressor has lighter and thinner blades for quicker spool (100-200rpms MAX).

One benefit of a Big 16G is you generally don't hear the boost creep issues which seem to plague the Evo III. This is because of the different turbine housing, I'm sure.

I ran a Big 16G on my FWD TSi for years and loved it. Couldn't imagine how an Evo III 16G would be better unless it was free or I was planning on running lots of boost to make the better-flowing turbine housing more useful.

well, i am putting it on a 2g fwd with 650cc injectors, safc,and all other supporting mods, with fully built bottom end. but for now, i will keep the stock cams.
justin, what do you think would be the max boost for it as a street car with 93 octane?

 

[Bender]

I ran 12.5 on a similar turbo you are describing at 21lbs of boost. By all means it is a good turbo.

 

[Herbal]

sweet, good news for me huh thanks.

any other comments on the 6cm housing?

 

[Bender]

If you use it.. hog it out, especially down in the throat of it. I do all my own porting, and ported my 7cm to 8cm..

If you are looking for the most power, I advise going with a ported 7cm housing as well.. even if it isn't brought out to 8cm's.

 

[JusMX141]

I do all my own porting, and ported my 7cm to 8cm...

Impossible.

Sure you opened up the volute a little at the entry, but you can't port the entire radius, nor can you change the geometry of the housing and the angle of how the exhaust flow hits the wheel through porting.

http://www.dsmtuners.com/forums/turbo-system-tech/356175-i-ported-6m-7-cm-manifold-turbo.html

 

[Bender]

Obviously the whole housing wasn't 8 cm.

It was 8cm matched to my manifold, then it was down to 7.5 at the wastegate. I radiused that, and opened up the flange. It then continued with 7cm until the housing walls started getting too thin for my taste, then I followed those contours down to the radius. The housing was then blended to form to the radius.

And who said I changed the way the pulses hit the turbine wheel?

 

[PieEyedPiper]

I do all my own porting, and port-matched my 7cm housing to an 8cm gasket..

Fixed.

 

[Bender]

Port matching doesn't open up the throat, and offers very little power gains.

Obviously someone with no experience die grinding or extrude honing thinks something is impossible because he has never done it.

 

[Herbal]

i wouldnt keep it on there or anything, im saying WORST case in a pinch i could run it. i have no illusions which is better but the difference between parts can get blown up on the internet.

One benefit of a Big 16G is you generally don't hear the boost creep issues which seem to plague the Evo III. This is because of the different turbine housing, I'm sure.

the big 16g gets a different housing then the other 16gs?

 

[the_mork]

It has a different housing than the evo3 16g but the same as the s16g. The evo3 16g is lighter, made of a more crack resistant material, and is shaped slightly differently. Except in terms of boost control it is the superior housing. How superior you ask? Enough to make them cool, not enough to make you want to throw away your other housings.

 

[Herbal]

awesome reply. most of the ones id find would be from bigs or smalls if they were older. id rather not deal with boost creep then have the ultimate flow anyways.

 

[JusMX141]

It was 8cm matched to my manifold, then it was down to 7.5 at the wastegate. I radiused that, and opened up the flange. It then continued with 7cm until the housing walls started getting too thin for my taste, then I followed those contours down to the radius. The housing was then blended to form to the radius.

Sounds to me like you're confusing cm as a unit of measurement with cm2, the measurement of volume of which our housings are described.

What you're basically telling us is, in Garrett terms, you ported a .48 a/r housing into a .63 a/r housing which, as I stated above, is impossible. You can't change the volute of the radius, nor can you effect how the exhaust flow contacts the turbine wheel.

What you have done is lower the velocity of the housing by making the "funnel" area at the entrance of the housing larger. Dsm-onster explains it better here:

"Your volute still necks down after the entry before the turbine blades. You didn't change the a/r of the housing doing this. A 7cm^2 housing has a larger a/rthan a 6cm^2 housing. And porting the inlet to 7cm DIAMETER doesn't have anything to do with 7 square cm of area. If you measure, you will see that your inlet diameter is in fact only 6.5cm wide....so you didn't increase flow of the housing at all- what you did was increase flow of the transition.

. . .By doing so you've now you've increased the volume of the collector. Larger volume lowers velocity; smoothing increases velocity. So it comes out in the wash."

 

[Bender]

I understand what you are saying... but it is not entirely correct.

An A/R ratio is just the ratio from the area of the collector/housing over the radius from the center of the turbine to the middle of the housing (going perpendicular to the inlet). Can you not change the inside area of the housing? Yes. You can. I have been doing performance porting for over 6 years, and I am going to go with my personal experience over you talking about what you heard.

Also, opening the collector does SLOW down the velocity of the exhaust gas. That is why a turbo with a .63 A/R spools so much quicker than one with a .83, and a .90 compared to a 1.10. However, you gain the ability to force more air into the turbine, and less out the wastegate. This greatly increases higher rpm performance, since the turbo is no longer being "choked" out.

 

[JusMX141]

I am going to go with my personal experience over you talking about what you heard.

Never did I say I "heard" anything, and I still don't see the point you're trying to prove.

If the nozzle area of the housing is the size of a quarter, it doesn't matter whether the inlet of the housing is 2" or 6", it will only flow the amount of air that the open area of the housing around the turbine wheel will allow.


If you're pouring oil into an engine using a funnel and the opening of the funnel is 1/2", it doesn't matter whether the mouth of the funnel is 1" or 6 feet in diameter, it will only allow "x" amount of oil into the engine at a time.

 

[Bender]

Air compresses, where as oil does not. The more air you can get there, and the more force you can push into it, the more air you can compress into that little hole.