JM Performance

Ok, I talked to the guys at F-Max and told them what I have (2000 LS) and what I want ( super-reliable, daily driver) and this is what turbo specs they told me to get. Tell me how they sound to you.

T3/T4
B Compressor housing
S trim compressor
Stage 2 turbine wheel .48A/R

If some of that sounds off, its because I'm not really sure what it all means and how to say it right, but those are the specs they gave me.

So....what'd you think?

boomslang

I'd go with a .63 A/R and stage 2 wheel. .46 or .50 compressor trim. I don't know what S trim is. I like my E housing but have never tried a B.

Seraph0

Sounds decent except for the .48. Get a Stage2 with a .63.

s-trim... i know what it is but havent looked into it enough to support or condemn.

Rob03Pro5

I would stick with the .48 stage 2 because you said you have an LS right? And they have a shorter redline than that of a GSR.. something like 6750 rpm? If so, you wont get much advantage from the .63.. only thing you might get is more lag.. and with a short redline, that can suck. Here's my rule of thumb: GSR=.63/ LS=.48/ Civic Si=.63/ Civic EX=.48

JM Performance

Rob: Yeah, thats what the F-Max guys were saying. I think I'm gunna go w/ this setup.

SpeedMonkeyRacing

hehe....convinced another guy to the darkside

Jeff-

Doodoo

I have a .48 on my LS. Like it just fine. Some lagginess but I don't complain when it fully spools!

ArizonaTurbo

I think the .48 Exhaust housing is way too small! i woudll stick with a Stage III .63 AR housing!

TurboInteg95

I just did a quick calculation and looked at the compressor map and it looks like the T04BS-3 trim should work about perfectly. I would go with a .63 exhaust with a stage 2 wheel though. there shouldnt be much lag. Although the .48 with the stage 3 wheel might also work. That's kinda of up to you.

JM Performance

I don't really know enough about this to make a decision. What differences would there be between a .63 stage 2 and a .48 stage 3?

Rob03Pro5

Here's the thing. Get a .63 if you are seriously worried about not having any top end. But with your 6800 redline, that wouldn't be a problem with a .48. These guys are really used to their GSRs and all have .63. That is good for a high reving motor. It is sort of a waste to get a .63 when you have no "top end" (6800+ rpm) to gain anything from... all you'll get from a .63 is more lag compared to a .48. The different stage wheels also affect lag and top end power. Stick with a .48 Stage II. The stage III wheel is just overkill .. but this is my opinion. All I know is that the people at F-MAX know what they're talking about.

JM Performance

Cool Rob, that sounds great. Thanks for explaining the differences to me and telling me why different ones are better for different people. You da man!

Peter K

hey i'm also getting the fmax kit and i was wondering if the power potential of the .63 is more than the .48. when should i see full boost if i opted for the .63 with the stage 3 wheel compared to the .48 with the stage 2, the .63 with the stage 2 wheel..and whatnot. tanks

Peter K

another thing. i thought that they were giving the t3/t4e not the b with the ls kits??

VTC_CiViC

Ok I'm glad somebody brough this up cause this is one of the turbo newbie questions I've been meaning to ask. When people refer to different wheel sizes like .48 and .63 etc.. what EXACTLY are you talking about? I'm guessing it's got something to do with the physical size of the turbine wheel or blades correct? Numericaly bigger meaning physically bigger (hence .63 spools slower than a smaller .48 but provides awesome top end), is this a correct asumption? Let me know Turbo guru's and thanks for the 411 guys.

Rob03Pro5

VTC_CiViC,

The .63 and .48 numbers people are referring to are the air ratios the exhaust housing has. The bigger the number, the more air can go through the housing. The Stages are the wheel sizes. Bigger = more top end hp but also has more lag.

Here's an example:
A .63 and a .48 both have a Stage II wheel. That means that the actual wheel size is the same on both of them. The only difference is the A/R.. which is .63 and .48. The .63 will give more hp top end (6500rpm +) compared to the .48 BUT the .48 will spool lots quicker. This is why for a car with a redline between 6000-6800 should use a .48. They wont benefit from a .63 as much as a car with a higher redline.

b18bturbo

how are you going about basing that. Are you actually looking at the compressor map of the t3/t04b trim based on what typical honda b18b is running.

smoothludey2

Couldn't he set his redline higher using Hondata? Then the .63 AR would seem feasible.

Rob03Pro5

Compressor maps have hardly anything to do with Exhaust housings. They dont change the compressor's characteristics.

b18bturbo

i am jsut asking how are you basing your theory that .48 exhaust housing is better than .63 based on just rpm. Have you ever done a compressor based map vs what the air flow characteristics of a b18b are.

Rob03Pro5

Oh I understand what you're asking now. No, I haven't done any sorts of airflow tests. I'm basing my "theory" off of previous B18b users and other cars with lower redlines than that of a B16A or B18C1/5. I have noticed that cars with lower redlines need a smaller exhaust housing than those with a higher redline. I've also seen GSRs with the .48 exhaust housing not making nearly as much hp than a .63. This is because the .63 carries on the turbo after 6500rpm.

Seraph0

What Rob says makes a lot of practical sense. I don't know the the theaory about what supposed to happen, but what he says is true because I have experienced it.

What I want to know is what would be the difference between:
Stage2/.63 and Stage3/.48

I have had a Stage3/.48 on my GSR and it choked top-end something nasty. I am wondering what a Stage2/.63 would feel lik both spool-up wise and top-end-wise compared to a Stage3/.48

b18bturbo

the stage 3.48 is just too small for any b18c model. it will start to choke at around 7200 rpm. The exhaust gases will not evacuate in a fast enough manner. Not putting a stage 2 .63 on a b18c you will experience lag from 800rpm-3500rpm before full boost is reached. The car still flows up to 8800 rpm with out any deficiency in the flow of the turbo. on the other hand the stage 3 with .48 spool approx 500 rpm faster than the stage 2 with 68. its all about what you want to do. Actually if you canfind a ihirhb7 or ihirhb8 thats the turbo to go with.. I been trying to find compressor maps from it for years but i cannot find anything. you allready know that mark

Peter K

so what i should do since i have the ls is to go with the stage 2 with the .48...but what is the full potential of the stage 2 with the .48 a/r?

JM Performance

sexychinaman (hehe): I have a ls too, and after reading what everyone says, I'm gunna go w/ the stage 2 .48. Our cars only rev to 6800, so we dont need the high rpm flow of the .68. Since we don't need it, we can take advantage of the faster spooling time.

See, sometime it IS better to have a LS. non-vtec power!!!