asianspeed

I'm planning a daily driven (< 300 hp), turbo project. I've got a 99 stock ls, that I will run between 7-10 psi. I'm trying to figure out which turbo would be best for my application.

Would I be better off with the smaller t3 60 trim .48/.60 a/r that will give me a faster spool up, around 2,500 rpms? Or would I be better off with a t3/t04e 57 trim .50/.63 a/r that will take a little longer, 3,250 rpm's?

When comparing the compressor maps between the two at 10psi, my peak power for the b18b is at 5,000 rpms, which is in the middle of the 74% turbo effiiciency, and stay there until 6,000 rpms, then from 6,000 to 7,000 it's in the 68-75% range; for the t3 60 trim. I'm guessing that at about 6,000 is where the turbo will seem to die down.
On the map for the t3/t04e 57 trim at 5,000 rpms it hasn't reached the turbo's maximum efficiency yet, it reaches it at about 5,600 rpms...but it stays there until redline at ~ 7000 rpms.

With these maps, I'm not experienced enough to know which would be better. Starting to boost ~750 rpms earlier and starting to top off at 6,000 with 68% turbine efficiency OR boosting later and staying the in 75% turbine efficiency, but not getting there until 600 rpms after my car reaches it's peak power. So I was hoping someone could help me out with real world experience or help with figuring out those darn compressor maps and what's a better for my application.

Please help, I just learned how to plot and read compressor maps today, so I'm very new to this...educate me if there is something I'm missing.

Thanks.

InTeGrA B18b1

i got a 57 trim and its not really a good if your start from low rpm such as 3k on 3rd get, if you start 4k on 3rd gear your pretty much in your power band. More top end and more power. Im thinking that even though it lags when you switch from 1st to 2nd to etc 5...... your in your power band so the big turbo would be good for draging and highway. the 60 trim will be good for that instant power as soon as you press the gas.


YOu will beat the 57 trim from lower rpm to 4k and from there 57 trim will take over. If if makes sense then if it doesnt well i tried my best hope i helped you.

black04

I'd say go with the 60 trim. That smaller turbine will have a quicker spool up and be a more streetable daily driver. More practicle for daily driving and getting around IMHO.

hybridsol

Check out this site, there is a lot of discussion on this topic, with dyno charts:

http://www.boosted-hybrid.com/

Generally speaking, you want a turbo to be matched to what you will have:
3" exhaust?
Downpipe size?
Manifold style?
Driving style?
Torque curve?

Most people intrested in drag racing will take the 4000-8000 rpm power over the "drive-ability" of a smaller turbo.

A small (0.48) turbine A/R will help spool the turbo faster, but will hurt top end Hp. A 3" exhaust will allow better use of a larger turbine (.63) A/R

For the compressor, look at the dynos on the site, generally a 57 trim is good for street use, although precision turbos are worth looking at.

Good luck, and post back how you do...

SlowTeg

I'm assuming you're talking about a 60 trim t3/t4e trim right, w/ .48 a/r turbine housing? If you plan to not up the boost and try to shoot for alot more power down the road the .48 a/r turbine housing is your best bet. You will have noticeably less lag w/ the .48 compared to the .63 a/r, and it shouldn't hurt your top end too much on the b18b if you plan on sticking with the stock redline. The .48 will spool in alot quicker and be alot more fun on the street.

If you do plan on upgrading and making more power later on, the .63 a/r housing is definetly the way to go. At higher boost levels the .48 will choke the top end and you'll wish you went w/ the larger turbine housing. Bottom line, if you're sure you plan on only making <=300whp I'd stick w/ the .48 a/r housing because spool will be much quicker and top end isn't a huge concern if you're running an ls. The .48 should be some fun on the street.

-Mike


Modified by SlowTeg at 2:05 AM 11/30/2004

asianspeed

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">Check out this site, there is a lot of discussion on this topic, with dyno charts:

http://www.boosted-hybrid.com/

Generally speaking, you want a turbo to be matched to what you will have:
3" exhaust?
Downpipe size?
Manifold style?
Driving style?
Torque curve?

Most people intrested in drag racing will take the 4000-8000 rpm power over the "drive-ability" of a smaller turbo.

A small (0.48) turbine A/R will help spool the turbo faster, but will hurt top end Hp. A 3" exhaust will allow better use of a larger turbine (.63) A/R

For the compressor, look at the dynos on the site, generally a 57 trim is good for street use, although precision turbos are worth looking at.

Good luck, and post back how you do... </TD></TR></TABLE>

Generally speaking, you want a turbo to be matched to what you will have:
3" exhaust? 2.5" e-cutout exhaust before the cat
Downpipe size? 2.5", unless I can squeeze a 3" past my a/c
Manifold style? blox manifold (looks like inline I believe)
Driving style? mostly street, but of course I'll take it to the strip. but 95% street.
Torque curve? highest torque I beleive is at 5000 and slows down reaching 6900 rpms.


What is "top end hp"????? Is that top end accordin to a vtec engine or non-vtec. Because my "top end" is 6900, but that sure isn't the top end of a gs-r. If someone can define that, it would help a lot. Because I don't really care if either of the turbo's make great hp in the "top end"....unless it's my b18b's top end.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SlowTeg &raquo;</TD></TR><TR><TD CLASS="quote">I'm assuming you're talking about a 60 trim t3/t4e trim right, w/ .48 a/r turbine housing? If you plan to not up the boost and try to shoot for alot more power down the road the .48 a/r turbine housing is your best bet. You will have noticeably less lag w/ the .48 compared to the .63 a/r, and it shouldn't hurt your top end too much on the b18b if you plan on sticking with the stock redline. The .48 will spool in alot quicker and be alot more fun on the street.

If you do plan on upgrading and making more power later on, the .63 a/r housing is definetly the way to go. At higher boost levels the .48 will choke the top end and you'll wish you went w/ the larger turbine housing. Bottom line, if you're sure you plan on only making &lt;=300whp I'd stick w/ the .48 a/r housing because spool will be much quicker and top end isn't a huge concern if you're running an ls. The .48 should be some fun on the street.

-Mike


Modified by SlowTeg at 2:05 AM 11/30/2004</TD></TR></TABLE>

Actually I was talking about the 57 trim t3/t04e, with .63 a/r turbine housing. The most I would up the boost would be to 10 psi, due to the map sensor restriction. So either turbo will be boosted to a max of 10 psi.

Can someone give an estimate of what hp the t3 60 trim .48/.60 a/r is good for? Just curious, but I don't plan on building my engine yet, so I'm planing on keeping things under 300 hp. I hear that's when things start to break. But I deffinately want to be above 220 hp. Is this acheivable with the t3?

Thanks

asianspeed

Thanks for all your help guys. I researched a bit more and I've decided to go with the t3 "super 60" .60/.63 or the t3 60 trim .60/.63....whichever I can find the best deal for. I think either of those will help me reach my goals.

Thanks again