Stock turbo flow map

[91White-T]

There's a compressor flow map for stock turbos on page 161 of the 1992 FSM, I know I've been looking for one and could never find it...

[boostjunkie]

I wish I could access that fsm. For some reason I can't open any of the links. I can save them to my harddrive but can't open them

[vrg3]

91White-T - I presume you mean page 161 of the PDF Josh posted? I don't see a compressor flow map anywhere there.

I remember looking through the entire 1992 FSM for a compressor map a while ago with no success... The closest I've ever found are the IHI images on this page:

http://www.graphics.cornell.edu/~v/compressormaps/

I think the RHF5 is similar to the RHB5 we have, but I don't know... in any case, what's on that page are not proper maps.

[91White-T]

Here's the link for it
http://www.finleyweb.net/docs/SubaruEJ2 ... nual-2.zip
Page 161, right near the end.

[vrg3]

Woah! Cool! I didn't notice that that was included there! That's not part of the factory service manual.

I wonder where that came from... Is IHI BRL4016 the code for our compressor wheel?

[Legacy777]

That compressor map is in my scans...at the end of the engine & elect.

You guys do know you can hit the show/hide navigation button and it will display all the bookmarks I've setup......I need to figure out a way for the panel to stay open....grr..

boostjunkie.....what version of acrobat viewer do you have?

[legacy92ej22t]

Cool, I'll have to check that out when I get my Broadband back up .

Hey 91 White-T, are you really running 17 psi on a VF10? That seems pretty far out of the efficiency range for a VF11, let alone a VF10. Do you notice if you pull much harder at 17 psi then at 15 psi? Just curious because I didn't think we could push that much air with either the VF10 or the VF11.

[Legacy777]

I've updated all the pdfs, the bookmark index pops out automatically now, which gives you an index of pretty much in the scans.

So if you're not sure what I'm talkin about, d/l the new ones.

[91White-T]

Yes I am, and there is a difference between them though not all that much. I've seen up to 22psi in 4th gear before with no detonation, but I turned it down after I saw that...

[legacy92ej22t]

What kind of I/C setup do you run? Do you run a Saab 900?

I would be interested to know what kind of exhaust temps you're getting.
Are you running an EGT?

[91White-T]

Yeah, I have the Saab IC with a WRX hood scoop. I'm not running an EGT unfortunately, but I'm sure the EGT's are up there...

[91White-T]

I was messing around with some turbo calculators, and the map to find where the stock turbo is most efficient. I used the Volumetric Efficiency calculator at www.turbofast.com.au and found that for a stock EJ22T, the VE is right around 90% at 5600rpm.

So using the equation for airflow in CFM:
135(Disp in CID)*5600(rpm at HP peak)*0.9(VE)/3464=~194CFM or 5.91 cubic metres/min
Pressure Ratio (stock) (14.7+8.7)/14.7=1.59

Those numbers on the graph put the efficiency right in the middle of the 76% curve @ ~120,000rpm. Now a somewhat opened up intake/exhaust system would increase the VE a little bit, so the flow would go up, we'll say between 6 and 6.5. So in this range using the flow map, it looks like a Pressure Ratio anywhere between stock (1.59) and about 1.9 (13psi) keeps the turbo in the 76% efficency range @ ~140,000rpm.

So it looks like the stock turbo is most efficient at about 13psi on a slightly modded EJ22T. Please feel free to chime in and or correct anything I screwed up, I'm still learning about compressor flow maps.

[legacy92ej22t]

13 psi sounds about right.

I notice you turned your boost down too.