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View Full Version : Those with BT. What do you like better 48ar or a 63ar?



grillhands
10-05-2010, 02:02 PM
I've only been in cars with a 63ar or bigger. I was just curious to know how does the 48ar feel on a BT? Does it choke it too much on top end? Is it fun for DD or scca? Does it suck on the highway? Just wanted to hear some thoughts.

ScratchRob13
10-05-2010, 04:00 PM
I've only been in cars with a 63ar or bigger. I was just curious to know how does the 48ar feel on a BT? Does it choke it too much on top end? Is it fun for DD or scca? Does it suck on the highway? Just wanted to hear some thoughts.

What size housing you looking for? .63 like I have on 3076 does let it spool better, but has some surging issues. I mean if you need to see the difference in just hotside take a peek at this:

http://www.youtube.com/watch?v=nfVmBrhbWWw
vs me and an as fast if not faster s4

http://www.youtube.com/watch?v=2yQZBLyswrk

Dynamite
10-05-2010, 04:17 PM
Bassed ran a hybrid bullseye s256 with a s258 compressor (from memory might be wrong about the exact hybrid details) and a A/R of 55, it didnt flow near the 55lb/min he claimed. So its not really a good comparison. Basically the lower the AR the quicker the spool but the less flow you get up top causing it to choke. Cant really tell you what one to go with though. what turbo were you thinking about going with?

grillhands
10-05-2010, 05:04 PM
i got a t3/t4 46 trim with a .63ar already for the past few months and it just seems like a dog anything under 4.5k.

ScratchRob13
10-05-2010, 08:15 PM
Bassed ran a hybrid bullseye s256 with a s258 compressor (from memory might be wrong about the exact hybrid details) and a A/R of 55, it didnt flow near the 55lb/min he claimed. So its not really a good comparison. Basically the lower the AR the quicker the spool but the less flow you get up top causing it to choke. Cant really tell you what one to go with though. what turbo were you thinking about going with?

It being only .55a/r was the point.

It sucked in the top end... and really didn't have much low end power either, as seen by the domination by the S4... however... I have no low end... as seen in the first pull... but if I spool I do have power up top.

.48 would be useless I feel.

JumboBlack1.8
10-06-2010, 09:34 AM
I run a .82a/r GT30r on a 2.0 block. The spool definitely isn't nearly as bad as I'd feared (although my lightweight forged crank, lightweight flywheel, and bigger displacement have a lot to do with that...). I wouldn't get this housing on a stock displacement, but, with more displacement and a built head (mine revs to 8.5k), you'll get a GREAT top end that doesn't stop pulling.

I wouldn't go for any turbo smaller than .48a/r. If you drive a 1.8, you've just gotta accept the fact that we have NO bottom end.....the fun is up top

grillhands
10-06-2010, 10:45 AM
I run a .82a/r GT30r on a 2.0 block. The spool definitely isn't nearly as bad as I'd feared (although my lightweight forged crank, lightweight flywheel, and bigger displacement have a lot to do with that...). I wouldn't get this housing on a stock displacement, but, with more displacement and a built head (mine revs to 8.5k), you'll get a GREAT top end that doesn't stop pulling.

I wouldn't go for any turbo smaller than .48a/r. If you drive a 1.8, you've just gotta accept the fact that we have NO bottom end.....the fun is up top
LOL..so true.

Dynamite
10-06-2010, 01:39 PM
JumboBlack when do you hit full boost on your setup?

black99.5a4
10-06-2010, 02:25 PM
i got a t3/t4 46 trim with a .63ar already for the past few months and it just seems like a dog anything under 4.5k.

that is just how the .63 t3/t4's are.. Laser Viking is running a t3/t4 50 trim with a .63 and 18psi is around 4400

JumboBlack1.8
10-06-2010, 02:33 PM
JumboBlack when do you hit full boost on your setup?

Not sure EXACTLY where....but its somewhere around 4.6-4.8k.....I hardly look at the tach at that point.....when boost hits, the car demands your FULL attention

ZimbutheMonkey
10-06-2010, 02:55 PM
Bassed ran a hybrid bullseye s256 with a s258 compressor (from memory might be wrong about the exact hybrid details) and a A/R of 55, it didnt flow near the 55lb/min he claimed. So its not really a good comparison. Basically the lower the AR the quicker the spool but the less flow you get up top causing it to choke. Cant really tell you what one to go with though. what turbo were you thinking about going with?

I spoke to 'wild bill' from Bullseye Power yesterday and he said that having a stainless steel turbine housing makes a big difference in spool time. Reason being is that it allows the exhaust charge to retain it's heat/energy and transfer it to the turbine. He said that a SS .55 A/R would spool like a cast iron .48 A/R. I know it sounds kind of unlikely. However, given his knowledge I'm inclined to believe him.

If and when get the funds to upgrade past the GTRS elim, I was thinking I may run an extended tip S252 with a .55 A/R SS housing. If I understood Wild Bill correctly it should flow similar to a 3071r with an equivalent or faster spool. Plus it would be rebuildable if something happened.

I guess in your case, it may be of benefit to get a stainless steel .63 A/R to bring it close to a .55 A/R cast iron housing. Ceramic coating the manifold may help a little as well. However, the SS turbine housing would be the greatest advantage.

As for Bassed's setup, I don't know that he ever had it working properly. He was one of the first to run this kind of turbo on the longitudinals and I think he had a pretty rough tune. Also, he was running against a wicked fast stage 3+. Had he been running against a garden variety 3+ it may have been a better outcome. Not to get into a 'what if' contest here, however it's something to consider.

94jedi
10-06-2010, 06:03 PM
i got a t3/t4 46 trim with a .63ar already for the past few months and it just seems like a dog anything under 4.5k.

I had a 50 trim w/ a .48 a/r. Although it was a gorilla on crack starting at 3700 rpm, I always felt like it teased me and left me wanting more up top.

grillhands
10-07-2010, 06:07 AM
that is just how the .63 t3/t4's are.. Laser Viking is running a t3/t4 50 trim with a .63 and 18psi is around 4400

Mine comes on a little sooner than that but i have to check. I don't like to go into boost in 3rd,4th or 5th unless im over 4k. It's just my personal preference.

black99.5a4
10-07-2010, 01:36 PM
I had a 50 trim w/ a .48 a/r. Although it was a gorilla on crack starting at 3700 rpm, I always felt like it teased me and left me wanting more up top.

werent you only the standard stg1 or 2 compressor wheel? had you of upgraded to stg3, you would of gotten the output of the .63 ar housing with the spool of the .48

20vpower
10-07-2010, 04:23 PM
Not sure if i have the stg 3 wheel or not (probally not) but on my 50 trim .63 im at ~10psi at ~4k rpm. This is however on an atp style dp with stock post cat dp to a 2.5 exhaust. So Im sure it was killing my spool. Car is back to stock temporarily (smog check) but should have a full 034 3" exhaust back on with the 50 trim in a couple of weeks, ill post my spool then.

94jedi
10-07-2010, 06:07 PM
werent you only the standard stg1 or 2 compressor wheel? had you of upgraded to stg3, you would of gotten the output of the .63 ar housing with the spool of the .48

I'm not positive but I thought I read somewhere or got an email from garrett (based on my s/n) that it was indeed a stg 3 wheel.

Dynamite
10-07-2010, 09:37 PM
As for Bassed's setup, I don't know that he ever had it working properly. He was one of the first to run this kind of turbo on the longitudinals and I think he had a pretty rough tune. Also, he was running against a wicked fast stage 3+. Had he been running against a garden variety 3+ it may have been a better outcome. Not to get into a 'what if' contest here, however it's something to consider.

Na bassed never did get it running well, he only got to about 330awhp on a 2L, there are 2871s round that will do that, one of the b6 guys is getting close to 350awhp with a HTA2868 on a 1.8. Its interesting you say that the Bullseye guys claim that the stainless housings help so much, I had never thought of that, but if the SS housing do have a higher specific heat capacity than the normal ones then it does make scene. it would be interesting to know how much it really helps and if there is a down side to it. I have always liked bullseye, it would be interesting to see how a s252 goes, I have contemplated a s256 as rather than an HTA3076, it really would be interesting to see a real comparison without anything else changing. The faster spool without the lower AR would be really good. Also I have to agree, Evil's s4 is probably one of the quickest k04ed cars out there, although not to start another flame war with the s4 guys, a well set up BAT will take that s4, something like millitant grunts old setup would give it a good run for its money.

A4Rob
10-07-2010, 09:40 PM
You should run at least a 63AR.