Hello guys, I am a new member, and although I signed up solely for the purpose of asking the question, I found myself posting in other threads already. This is a very good board, I commend you on keeping it neat, clean, education, and free of that oriental food we all hate.

Anyway, the question: I was wondering if any of you have any tested numbers of what kind of airflow one would expect from a B18 at a certain level of boost. I'm looking for boosts in the 6-8 psi range, but whatever you can give me would be great. Also, airflow in lb/min, cfm, g/rev, etc, is fine, I can always convert if it is not what I need.

Also, if you could include a short list of mods, most importantly the turbo, intercooler, and exhaust, that would be excellent.

I need these numbers so I can do some compressor map research for a friend of mine who will be doing a turbo project in upcoming months. As such, does anyone know where I can find comp. maps for a T-25? I have found many mitsu turbos and a bunch of T3 variations, but no T-25....

Thanks for the space, and any help you can give me!

 

all i will tell u is that a T25 is wayyyyyyyyyyyyyy to small for any b18 vtec or non vtec honda motor. a GSR head is over 100% volumetric effecient and it revs to 8k.. a good sized street turbo for a GSR motor @ 8psi of boost is any of the T3/T04e family.

 

here is the most recent dyno of a properly set up turbo GSR at .5 bar, 7.25psi. these motors like their turbo's big. T25 just wont cut it im sorry. https://honda-tech.com/zerothread?id=370120

 

Too Small? Yes, I agree. WAAAAAAYYY too small? Sorry, now I don't.

As far as I can tell, at a boost level of about 7 psi on he 1.8 liter in reference here, we're talking somewhere around 400 cfm. That's like T-28 or small/medium T3 range, IMHO.

Anyway, back to the original question.... Does anyone have actual tested numbers for airflow? If I can get those, I will be able to figure out which turbos are too small, and which are right.

 

alright, it may not be wayyyyyyyyyyyyyyyy too small but its way to small if u r putting it on the car to make it fast. its great for instant boost in traffic. go ahead and put 7psi through a T25 and have fun making 175whp, maybe 190; **** u can do that on motor. ill run a T3/T04e and get 260hp and 200ftlbs of torque to go with it.

if u want to know the CFM of a gsr motor just put in the specs.
1.8L
1.58 r/s
100% volumetric efficiency
8200rpm's
i think thats all u need.

 

I can do the numbers, it comes out at approximately 400 cfm, which indeed is too much for a T-25 above a certain boost level.

However, numbers aren't always right! There has got to be some system that you people are using that allows you to see the airflow, and whoever is using it, please let me know what you see!

I just threw "T-25" in there, I'm not hell bent on using one. We'll probably end up with a T3 of sorts or a mitsubishi turbo, but I'd like those numbers so I can find the best fit.

 

It's been proven over and over again that a T-25, or T3 just won't put out the numbers that a t3/t4e is capable of. ****, even greddy's line of small Mitsubishi turbos "run out" on the top end while revving up to 8k+

 

I have to agree that the T-25 is too small of a turbo for a B18C... Above 6k... When figuring airflow, it seems people forget that it is only for a target RPM. A compressor is only effiecient at certain levels. I have a B20 that will be recieving a T-25 soon. I realize that, indeed, it is very small, but the B20 is all about midrange. So is a T25. This engine will never see over 7K. Boost response and linear torque are also nice things to have, aside from peak numbers. I'll see you at Epping. I've seen you there before. I have a slow red CRX.

 

Guys, this is not very productive. I have already rescinded my comment about the T-25, I looked at some numbers and realized that it's too small for this application. So, what do you say we STOP saying that it is too small? We all know that now!

That wasn't even the original question, yet all the answers I have are only about that. The question is, do you guys have some way of logging airflow? If so, can someone with this utility please let me know?


Was that note that you have seen me at Epping? If so, that's pretty cool. It's a small world. ) Give me a holler next time, I'd love to chat.

 

a t25 is too small for a b18c hehe

ok i emailed you 2 programs, one to calculate volumetric efficiency and then one to calculate the airflow your engine will make at any given rpm.

 

Using the programs sent to me by JCushing (thanks a LOT, that's some progress ) ), I get approximately 320 cfm of flow at 7000 rpm and 8 psi of boost.

That's not quite enough to warrant the 60-1 wheels you guys seem to be suggesting...

It is more than you want for a T-25 though.

What I see working is a Garrett Wheel like a 40-50 trim, or, due to budget constraints, a mitsubishi turbo such as a 14b or a 16g. The 14b stays above 70% efficency using the numbers above, which is ok for a budget, homemade turbo kit.

 

just out of curiousity, how did you do this?

A while backI asked around for what the VE% was for various VTEC motors, and not too many people knew them.

I did do a search on the web a while back and I found a good source that stated that the VE % for the H22 was 102% at 7000 RPM...and the S2000 had a VE% of 112% at peak HP RPM (whatever RPM that is).

So I'm guessing that the B16 and B18C1 and C5 are somewhere in between 100% and 112%. It's pretty commone for VTEC motors to be above 100% VE.

 

people use the 60-1 because it has been proven to make power. Compressor maps are only a guide to get you close, they cannot emmulate all of the real life characteristics of a motor. a 60-1 will make around the same amount of power as a regular 50-60trim up until 15psi, but it will do it less efficiently. 15-25psi is where the 60-1 really shines over the 50-60trim wheels.

for a junk yard set up a 14b might work, but its still really small. I wouldnt go smaller then a 16g, 18g will work nice.



[Modified by DIRep973, 9:09 PM 1/7/2003]

 

Yup, compressor map number crunching is no substitute for using other peoples real world experience. Dont use it as your sole method of selecting a turbo.

I did my number crunching BUT I also compared that with peoples firsthand experience with similar setups to what I planned on running.

 

i dont have the link for the VE calculator BUT i have the .exe on my computer and its really small. it uses your dyno sheet (NA) to calculate your VE based on HP, displacement, and what rpm you make your power.

i can email it to anyone that wants it as well as the airflow program that BlueSI2k made from this board

 

-so using a dyno sheet from a stock H22 (dyno sheets on http://www.ntpog.org)
-displacement = 2.2L (134.2 cid)
-200HP (155WHP/130WTQ)
-@7000 RPM

or an S2000
-I dont have a stock S2K dyno sheet
-displacement 2.0L (122cid)
-250HP (~195WHP)
-@8300RPM

what does your .exe say for ve%? I'm just wondering how accurate your program is. It's really hard to find the VE of any particular engine...I read that it was all a matter how the design is on the head, cams, intake and exhaust manifold as well as a few other parts.

 

using your numbers that you gave me i get a VE of 95.7 for the h22 and between 95 and 110 for s2k depending on how much power they put down.

 

hmmm, your numbers seem to be a little to low. The H22 should be ~102% however the S2K is close, but I think I guesstimated the WHP wrong. I used a 22% drivetrain loss---not sure exactly what their % loss is.

 

i used the #'s you gave me

 

yes, I know...and I'm saying that your VE% number might should have been a little higher. According to the site I found a long time ago, the VE should be 102% for the H22.

There could be a variance between the VE number that we get an the amount of WHP. But 155 is the average WHP number for an H22...at about 8 PSI there is a difference of 30 CFM between 95.7% ve and 102% ve.

both at 8 PSI:
~200 CFM @ 95.7%
~230 CFM @ 102%

 

For one thing, we're not going to be running more than 8-10 psi, and it may end up down at 7 all the time. This is a a budget project, half for the fun and the learning of it. If we had money, we could create a monster setup, because we have the knowledge to do so, but as always, money is an issue. )

I calculated 93 (ish)% VE, but keep in mind that this is NOT a VTEC motor. It is a B18 from a 92 Integra RS (I'm not sure what the letter is, is it B18A?). As such, it's not going to flow as much as a VTEC motor.

There is a possibility of a swap to a VTEC head after the rest of the kit is up and running, but we will worry about that later.

Also, I wholeheartedly agree with the statement about 40-50 trims, and the 60-1. I I planned on running more than 15 psi, we would certainly be running a 50 or a 60-1. However, with the budget constraints, and with the smaller amount of boost, it's not toally necessary.

It is in my experience that the 40 series wheels are not very good, I personally believe in going straight to the 50 trim if you're going with a garrett wheel. I know that 50 trims will support 400 awd whp on a DSM, without totally pushing the limits of the turbo. 60-1's, I'm not sure, but they have done 500-600 whp, and I'm sure they're capable of more.

On the other hand, this project's goal is 200 whp. Hardly a need for a 50 trim there. ) Although, if we could afford it, we would just do it, I think.

thanks guys!