Hi, all! Been busy for quite a while. Keep the TBI faith! I'm still working many MPFI thi


Did anyone ever flowbench a Holley "670cfm" unit (2"+ bore) to check for:

Dry flow (no fuel, only air, with and without pod?)

and

Wet flow (with injectors operating, std pod and raised pod?)


Thanks!

 

https://www.thirdgen.org/techbb2/sho...hreadid=278939

This guy is supposed to test a 2" unit soon, and it looks like he's testing them in every concievable combo of pod, and spacers. Should give us a good idea of what they actually flow. Of course this is all dry flow numbers.

 

Wish I could but I cannot view that graph, need an id and password...

Doesn't seem like it was flowed "properly", but the numbers are nice.

FYI, I am presently still using a 2" Holley TBI unit (actual bore is a bit larger) dry with pod but no injectors as the air control device for a Holley Commander 950 TPI ECU control with a Holley Single Plane vortec-style MPFI manifold, massaged E-Tec 200 heads with a whipple charger on top, Borla stainless equal length headers, 42pph Ford injectors, 383 GMPP short-block and full-time Innovate WBO2 closed-loop mixture control. I only rev up to 5,500 max (all that is needed!) and I do not seem to have airflow requirement issues. I do have the IAC wide open a high TPS settings and did put an electronic "purge" solenoid in the big power brake vacuum hose that open at 90% TPS, allowing more air.

 

That's a nice setup you got there. Good to hear that the wideband isn't showing any airflow restrictions up top either. That's a positive bit of information for anybody looking to build up a TBI engine. I'd ask you if it pulls any vacuum at WOT but I think that whipple might throw it off a little

 

So far, so good. Cam is mellow, too, so that helps. Comp Cams hyd roller, 112 LS, 218/224, about .500" lift, 269HR I think.

Can someone post that flow-chart graph from the link above so that I may see it?

 

Thats cool how you are trying to increase the air flow @ WOT. But then again why not?

 

I signed in on that sight, and the flow numbers look very good, and pretty much what we expected. Around 550 cfm, 30 or so more without the pod. The guy seems to know what he's talking about, the others that posted seem to think he was clueless since he didn't flow it wet. I've never seen, or even heard of flowing stuff wet, so I don't think it's really a valid argument, when we are just looking for numbers to compare to carbs.

 

BMONTEss, can you post the flow graph/pix so I can view it? Killing me!!!

Fast355, air is air, and a lot can flow through a 3/8" hose. Piece of mind.

 

This is for an LS1 TB, but it has flow vs throttle angle data so it's at least useful for reference purposes, even though it's a 75mm diam mono-blade design:

http://members.fortunecity.com/tunemaster/ls1air

Also note that the pressure differential for the test was 20.5 inches of water, so obviously the unit would flow more had the pressure differential been 25 or 28 inches. Even so, it still reached 663 cfm.

FWIW the LS1 monoblade TB has a flow area of 6.45 sq in (not incl the shaft and the blade shadow). A dual bore Holley TBIhaving 2-inch diam bores (i.e. this thread) has a flow cross section of 6.28 sq in. (again not counting the shaft and blade shadow), which is 97% of the LS1 unit. So it seems easily reasonable that the Holley unit will flow at least the 670 cfm that they claim.

And the data is consistent with Ken73's data on Crossfire single bore TB units machined to 2-inch diam, reposted here on TGO:

https://www.thirdgen.org/techbb2/sho...&highlight=cfm

 

thanks, Ken.

My Holley is untouched and the dia is 2-1/16" at its narrowest. Anyone else ever measure their diameter out of the box??? So, it's even more comparable to the single body you speak of... I suppose I could massage the thing for more flow but not going to bother until I have the need.

Man, I wish there was some real flow data out there for this thing.

Bye, all.

 

I'll try to post the graph here:

" just got done doing a flow rating on a GM TBI for:
4.3 - 5.0 - 5.7L TBI applications
the blue line represents a throttle body in full trim (injectors, injector
pod) no air cleaner.
the red line represents a throttle body in full trim with and injector pod
spacer installed (injectors, injector spacer and injector pod) no air cleaner.
the green line represents a throttle body with nothing installed.
the column on the left is air-flow in cubic feet per minute
the row underneath the graph is throttle position rated in volts from
a stock TPS.
the test was run with 1000cfm @ 28.00" temp 68.5°"

 

how did you mount the whipple to your manifold if you don't mind me asking?