Rain_man

I did a search already but couldn't find anything. I've pretty much learned to read the compressor maps thanks to BlueShadow's post but I have no idea how to select the a/r, wheel stage and how to map hybrid turbos. I know hybrids are t3/t4, but wouldn't you need a entirely different map to use to determine if it would work?

Any help would be great, thanks.

BlueShadow

Selecting turbine A/R's is not an exact science you dont use "maps", for it to be precise you would need to measure exhaust manifold pressure, or turbine inlet pressure, and comparison with boost pressure. (Maximum Boost pg 33)

since it's very hard to measure manifold pressure or turbine pressure, your left with good ole guessing. It ends up being a process of "Trial-and-Error", however it doesn't have to be your trial and error. Try asking around and see who has a similar motor and turbo setup. Then you find out what their boost characteristics are.

here are the typical A/R sizes for people with:
<U>H22's, H23's, B18C1, B18C5</u>
T3 stage 3 .63 A/R

<u>B16's, D16, D15's etc</u>
T3 stage 3 .48 A/R

I'm judging that by your SN you drive a GSR? if so what PSI do you plan on running and what HP are you shooting for? are you looking for very quick response, or very good top end RPM power? This will help us chose the right A/R for you.

BlackGSR

BlueShadow,

what about this setup:

-2.0 liters
-9.7 CR
-15+ PSI
-Turbo lag not a BIG issue. Just don't want my neck to hurt. I like "super" VTEC.

I was thinking about .80 A/R ... I love topend power.

BlueShadow

I'm assuming this is a CRVTEC or something, for 1.8L to 2.2L VTECs a .63 A/R's boost pattern looks like this:

7 PSI @ 3700-3900
10 PSI @ 4500
15 PSI 5000-5200

I would post a thread giving your engines specific specs and get every ones opinion on what boost would feel like from 3700 to your redline (whats you redline anyways?)

There was a post on http://www.preludeonline.com FI forum where different owners shared their boost characteristics and A/R sizes. unfortunately the site is down rigt now.


[Modified by BlueShadow, 7:58 AM 4/2/2002]

Rain_man

Actually a DC4 is the LS. So it's about 112 ci, 6800 redline. I'm looking to boost about 8 pounds.

When I did the compressor map for my engine it it looked like a T3 Super 60 trim would be good. The PR was 1.54 and max flow was 23 lbs/min. Anything below the Super 60 would have the redline off the map to the right. However this seems odd becuase everybody else is using a 57 trim for their GSR's and I know my engine doesn't flow more than a GSR.

BlueShadow

Selecting your own compressor by doing the math should not be your only way for selecting a turbo. ask the diffferent LS people and see what the 8 PSI people are using as far as compressor sizes, and compare your results to there input. Also the T3 60 might nnot work well for 10-15 PSI in case you decide to raise the boost in the future. The T04E 40" might work good too, but thats just going off the numbers, more than likely the T04E 40" will have a lot of upgrade potential whn you raise the bostwith your engine though a stage 3 .48 A/R migt be the way to go.

so ask around and see what 8 PSI of boost would be like on an LS with a T3 .48 A/R and a T04E 40". a T04B might work too, but judging by the numbers it would be too "small" but again, judging by hte numbers vcan be decieving.

Rain_man

Thanks for the tip, it really does look like I'm going to have to get some other opinions. I'm just wary of asking because some people are pretty clueless, but they talk like they know what's up.

One more question though, how did you know that the t4oe 40" would good to mate with the t3 .48? I mean that's two separate maps right? Shouldn't there be a hybrid map?

Stock@$$GSR

May sound stupid, but the TO4E 40 trim is bigger than the T3 60 trim, correct? I know the TO4E's are naturally bigger than the T3's, but the 40 trim compared to the 60 trim is throwing me off.

BlueShadow

Well like I said earlier compressor selection can be done by doing the math and using the compressor maps, however turbine selection is pretty much trial and error or guesstimation. whenever you do the math for compressor maps all that does is tell you the ideal compressor size for you. It's up to you to find out what turbine A/R will take full advantage of the compressor you have chosen.

Too large of an A/R and you might not even reach the full potential of your compressor, to small and you reach the compressors peak to early in the RPM range.

There are no turbine maps available, you just guess based on engine size, exhaust flow OR you guess based on other peoples experiences.

BlueShadow

well I was just trying to see what DarkSideDC4 was planning to do, and give him several options.

He said that he was planning on boosting 8 PSI, he didn't say if he was planning on raising that in the future.

The T3 60 and T4E 40" look like they would be operating close to the same range at 8 PSI, but just an EXAMPLE the T3 60 might only be good for 10 PSI MAX but the T04E 40" would be good for up too 15-18 PSI. I was just letting him know that in case he plans on raising the boost in the future.

so in short the T3 60 would be operating at close to its max potential on 8 PSI but the T4E 40" is only at say HALF of its potential. Thats just a HUGE way of over-simplifying it without going to much in depth.

Rain_man

Ah okay, that's the distinction I wasn't making, compressor and turbine.

I'm planning on upping the boost later, but only after I have my engine built to support the boost and increased redline. But I figured the engines were so different (stock LS vs. built LS/VTEC) that I would have to get a new turbo anyway.

I'm going to have to look at the map of the t4 and see... thanks for the suggestion.

Xerxes

that's some great info! Is the difference between the b16 and b18 really that significant that a .63 would be best for a b18 while a .48 would be best for the b16?

on identical setups wouldn't a .63 a/r on a b16 only spool up marginally slower than on a b18? It seems to me that you'd really be hurting your top-end with a .48 on a b16 vs. a .63 on a b18..


what about if it's a 10:1 compression b16 vs. a 9:1 compression b18?

just throwing out some hypothetical situations.. as a b16 owner considering getting a t3/t4 (who knows when though, i've discovered some enjoyable hobbies that are much cheaper than this damn car)

-Xerxes

BlueShadow

Thats true, I'm guessing that a .48 would work real well on a Civic EX, but for a Civic Si (99-00) its kind of a toss-up. I haven't asked too many Si owners what A/R's they run. I have seen a fair share of .48's and also .63.

Thats why I always tell people to get a second opinion besides my own.

BlackGSR

Xerxes,

Get the .63 A/R. You will be a little disappointed with the lower one.

I have a 2.0 GSR and I am also debating which A/R to get: .63 or .80. I'm leaning towards the later one ... will make more topend horsepower.

Rain_man

Was looking at the map of the T04e 40" and it seems that at 8 psi I would never hit the peak efficiency of the turbo, although all the points are on the map. The points are just below that center oval. But you are right, this turbo has much greater growth potential.

So let me get this straight (I hate being a n00b), it looks like a t04 would be a good choice according to the compressor map? This doesn't seem right however, because isn't the t40 a pretty big turbo? I figure if the b18c's a using hybrids, me with a b18b should be using something smaller not something bigger.

BlueShadow

well I can compare LS's and GSR's to H22's and H23's

a lot of people that use T04E 57" trims with .63 turbines on the H22 VTEC's is the same setup that most H23 NON-VTEC turbo people use.

H22 = 7400 RPM redline
H23 = 6800? RPM redline

but remember it all goes back to whether or not you plan on raising boost past 8 PSI to say 15-18 PSI in the future. I'm at work right now, but when I get home I'll do some quick math of my own between the B18B and B18C.