RedStarGsr

ive searched, but haven't exactly found if the 14b (1g dsm manual) will be good up to 8grand for a dohc vtec. lookin for some setup advice as far as management, and manifold for 8psi (internally w/g) I know this runs good on LS's but wondering if it will die out in extra 1200 rpms that the b17 has (what im running it on) thanks everyone.

InTeGrA B18b1

i think its a little to small considering its the size of a t3 but flows good

RedStarGsr

anyone else?

rickbusarow

I can't say from experience with a 1.7 DOHC or any other Honda engine for that matter, but I've got quite a bit of experience with several 14b-powered DSMs, each capable of sustaining ~15psi up to 7k. With the added displacement, the cold side's being asked to flow about twice as much as it would in your setup. If anything, I'd say your exhaust side would be restrictive. Modifying the o2 sensor housing to accept a dump tube would greatly increase flow and more than likely eliminate any problems you'd have, while allowing for a much quicker spoolup than any non-BB setup your buddies may be running.

RedStarGsr

thank you for your FIRST POST....ever..

anyway, so you're sayin do a dumptube (into atmosphere, or back into downpipe) and that would help it spool higher? I know the 14b is very capable on ls's and dsms, but just not sure of its power.

what exactly does a dumptube offer opposed to the regular 1g dsm 02 housing? thanks.

rickbusarow

Hey, I may be a newbie here, but not elsewhere...

Basically, it's like running an external wastegate for a few bucks. You use a dremel or die grinder to cut a hole in the wastegate pipe, then weld in a 1.75" pipe (so that nothing goes into the exhaust) and bend it down so that it vents down by the bottom of the engine bay.

When you're running a turbo below its ultimate flow capacity the wastegate's open, right? The lower the taxation of the the turbo, the higher the taxation of the wastegate. If the turbo's only reaching half its potential, the wastegate's likely being asked to flow quite a bit, and at 7k+ rpm that's asking a lot. The external dump frees up the downpipe and rest of the exhaust quite a bit, and the wastegate gets to breath freely. Some say the sound's cool while others hate it... I say that if you're running WOT you shouldn't really be concerned about the sound you endure in order to get maximum performance.

RedStarGsr

rick-
do you think a dumptube would help it spool up faster, OR do you think it would just allow me to rev the thing out to 8? Since the exhaust gas is not being stuffed into the downpipe and has its own path, then it can flow up exhaust gas correct?

still piecing all this crap together, and still thinkin bout it bout it...

RedStarGsr

bumpage

rickbusarow

Both. Any release in backpressure will result in quicker spool-up, and I'm told that the gain is rather substantial. Also, of course, less backpressure means more top-end power. In addition, of course, you get the pleasure of doing something rather innovative to your turbo kit.

RedStarGsr

whats the next step up from a 14b..is it worth it if im only pushin 8psi max, or should i just stay w/ the 14b and let the high rpms die? (or will they)

RedStarGsr

so 14b, 1.7l, 8psi, w/ a dumptube, 2.5 d/p, t/p and exhaust, what about intake piping...2" to smic? or would a fmic help it not run out of juice? PLEASE HELP, if im gonna dump some serious money into this setup i wanna know if its gonna spool all the way up or not. please...

rickbusarow

The next common step up is a 16g. They flow 55cfm more at 15psi, and lag isn't too bad. Of course, they're more expensive - maybe $500 more used when compared to the average used 14b. I wouldn't say it's worth it - yet.

2" intake piping should be fine... A SMIC (DSM, I take it?) would also be alright, but a Starion FMIC would cool better, look better, and flow a bit more. The pressure loss would increase ever so slightly, and lag may increase, but you can offset that by running more direct plumbing, going straight forward from the TB instead of plumbing it like an intake.

RedStarGsr

if the internal w/g is set at 8, and it doesn't creep, what will i be boosting with the smic and w/ the fmic (w/out a controller...yet)

also would the dumptube help the 14b flow to 8grand a little smoother. I realize it might drop off somewhere between 7000 and 8000 but if i got it tuned (hondata...payn in michigan) would it show where it started to drop off, and couldn't I just shift there, or am i stupid and should just look for a 16g or 18g to actually rev to 8grand? thanks. later

thanks again rick

rickbusarow

For some reason, I'm not getting emails to say you've replied... I do have it selected in my user options...

You shouldn't have a problem with boosting to 8k and beyond. The dump tube would help you to create a bit more power up top, but it shouldn't alter the boost seriously. Actually, a restrictive wastegate creates boost creep. The exhaust gas can't get out the wastegate, so it's forced into the exhaust turbine which in turn spins the compressor wheel faster. Again, you shouldn't have any flow issues, and there's no need to get a bigger turbo until you decide to build up your bottom end and fuel system.

fsp31

>>if the internal w/g is set at 8, and it doesn't creep, what will i be boosting with the smic and w/ the fmic (w/out a controller...yet)<<

Yep, what Rick said. Dang Rick, sorry we're all cracking on you for only having a few posts!! We're just not used to new people who actually know what they're talking about...

If the wastegate is set to open at 8 psi (actually, it'll open partially at like 4 psi, then be all the way open by 8 psi), then the intercooler will have virtually no effect on boost level. It depends on where you route the WG vacuum line. It should go straight to the intake manifold. No tees either, just a dedicated vacuum line because that is one vacuum line you *do not* want to have screw up. If you route the WG vacuum somewhere in the charge piping, the WG will be popping open every time you get off the gas, and boost levels will also reflect restrictions you may have, like a bigger intercooler. The only place you really *care* about getting 8 psi is inside your intake manifold, so that's where the WG vacuum line should go.

BTW, I have a T25 from an Eclipse GSX. The factory setting is for 7 psi on the nose. My WG vacuum line is too long so I get a nice spike up to about 8.5 psi occasionally. I don't wanna fix it though.

RedStarGsr

thanks for your help gentlemen--
fsp31- what engine are you running the t25 on? so far i have 1 person that says i should be ok to 8k without it dying off...have you ever seen anyone else use this setup or just guessin? sorry for lame questoins..

rickbusarow

There's a really simplistic formula I like to use to illustrate my point to Honda guys:

d x p x r = f

If a t25ed DSM can make 15psi at 7k rpm, d = displacement, p = psi, r = rpm, and f = flow, then

2 x 15 x 7000 = 210,000.

Meanwhile...

1.7 x 8 x 8200 = 111,520.

Like I said, it's really simplistic, but nonetheless you can see a B17 is asking just barely over half of what the turbo can do. It doesn't say anything about efficiency, but regardless of whatever margin of error my formula has, you WILL get full boost up to redline.

And like I said, I'm only a newbie here. I've been around, and I've made fun of a few noobs myself.

RedStarGsr

hmm...very interesting... might have to KEEP piecing parts together then...but man this new jun header really does makes the car come alive. (just imagine what 8psi would do!)

fsp31

>>d x p x r = f<<

I think where a lot of Honda fans get hung up is in volumetric efficiency. There is a lot of unqualified info floating around, but the general opinion (probably very biased) is that Honda heads are much more efficient than any other motor in the known universe. I've even heard someone explain that a B16A at 7000 rpm's actually flows more air than the DSM 2.0L motor at 7000 rpm's. I have never seen data to back up the claim though so I have no idea what the real numbers are.

My T25 is on a D16Y8*... converted from a Y7 (head, tranny, and ecu). I can definitely say that at 7 psi my setup does not run out of breath at the stock (6800) redline. I do plan to do some work to the Y8 head to get it to flow better sometime. We'll see how that affects top-end. Bear in mind that my car was *not* built for drag racing. I could care less about top end numbers in excess of 250 whp because it's useless in my chosen sport. I also want instant *GO* at 4000 rpm's and I definitely have that.

edited for stooped speling erorrss...

rickbusarow

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fsp31 &raquo;</TD></TR><TR><TD CLASS="quote">I've even heard someone explain that a B16A at 7000 rpm's actually flows more air than the DSM 2.0L motor at 7000 rpm's. </TD></TR></TABLE>

Well, that person's just talking out of their ***. Clearly, a motor displacing .4L more will displace .4L more. There's nothing mystical about that.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fsp31 &raquo;</TD></TR><TR><TD CLASS="quote">I think where a lot of Honda fans get hung up is in volumetric efficiency. </TD></TR></TABLE>

Exactly. Like I said, my simplistic little formula doesn't say anything about how efficient it'll be, but the boost WILL be there, and there will be plenty more in reserve if the bottom end and fuel system can handle it.

RedStarGsr

um..bump..anyone?

kpt4321

Rick, that formula is a good idea, but it's wrong for a couple reasons.

First of all, you can't just use straight boost pressure, you have to use absolute pressure, or pressure ratio. Otherwise, you're going to get all kinds of goofy numbers.

Second of all, VE does make a sizable difference here. However, not as much as some Honda guys get all hung out about.

My car, with a 14b, will hold 20 psi to 7000 rpm. I don't care how efficient your heads are, the heads on a DSM are not bad enough that 20 psi at 7000 rpm is less flow than 10 psi at 7000 for a Honda.

I'd like to see some real evidence as to how efficient these heads are anyway. From the numbers I have gotten for stock dyno charts for 1.8's, they are a bit more efficient than a DSM head, but nothing extraordinary like everyone seems to think.

I just finished build a turbo kit for a friend using a 14b. He's running the 14b on a non-VTEC 1.8 liter Integra, and the turbo works GREAT. I have run the numbers for flow, and this puts him at a very good point on the compressor map of a 14b.

A built motor with big cams, a big intake manifold, ported head, etc, would not be able to use such a small turbo, because it would flow more. However, the same goes for a DSM with comparable mods.

In short: For a regular motor without big mods, the 14b is a GREAT option.

turbodGSR

and were does CFM and compressor maps come into this?

kpt4321

What do you want to know about CFM and compressor maps?

With a VE of 110% (possibly a bit high for my friend's DOHC non-VTEC 1.8l) and 75% intercooler efficiency, the motor is pulling about 270 cfm of air (21.4 lb/min). This puts it right in the middle of the 14b's compressor map, at 76% efficiency.

On a 54 trim or such turbo, the efficiency numbers would be a tad bit higher, but in an intercooled, low boost setup like we are running, compressor efficiency numbers don't actually make much of a difference. The change between 72% and 76% is minute.

RedStarGsr

interesting KPT: i noticed you said a built motor w/ big cams, mani, and ported head would not be good for a small turbo....

would a TB, and intake mani be ok w/ this 14b? im considering runnina smic, or a stario fmic i can find one, and 8psi tops (probobly like 6.5 - 7psi after intercooler so im told) w/ a log style manifold. 2.5 exhaust. i just hope it wont drop off past 7 grand...do you think it will, and if it does how much will it drop off?

also: what do the effects of a dumptube add to the equation? gracias--