InternetRoadkill

Has anyone actually put a vacuum gauge on the on the intake plenum and measured the manifold vacuum at WOT during acceleration to see if the intake system really is as restrictive as folklore believes? I'm really curious about this. I would do it, but my vacuum gauge is kaput.

The reason I'm asking is that it looks like it would be possible to fit a modern high-flow MAF to our 22REs and remove the VAFM without having to change the EFI system out. But if the VAFM isn't the problem that everyone thinks it is, there's no point pursuing it.

Flash319

2 valves per cylinder is the problem, not the intake. Even if the intake is causing a bit of a problem, you are not going to get much by fixing it if any. 22RE's flow like poop. They are truck engines after all.

4Crawler

iTrader: (3)

My vacuum gauge easily drops to 0" Hg under wide open throttle acceleration. I do have a 3mm over bored throttle body.

X-Tool Pimp

MOD EDIT: (Lysmachia) BANNED!

Swansen

HAHAHAHA, thats good time, but yeah, the VAFM inlet is about the size of a pencil, and i don't really care, you just can't pull that much air through that like one square inch area.

ozziesironmanoffroad

just put a supra afm on it, it will open it up. remember its a truck engine, i dont care what you do to it, its not gonna be anywhere near a ferarri

Flash319

Toyota Engineers are not stupid like GM and Ford. I would trust that the intake is designed properly for the engine. Unless you modify something (bore size, turbo ect) I think you are pis$ing into the wind.....

you know what happens when you do that don't you? Don't ask me how I know.......

InternetRoadkill

The VAFM was borderline obsolete when it was introduced. It's a klunky solution to metering air into an engine. I don't know of any modern EFI system that still uses one.

The fun part is that I found my old MCU development tools and I still have a couple of prototyping units laying around looking for something to do, so the converter part is covered. I just need to write a program for it and make a wiring harness.

I also dug up a spare VAFM I had and hooked it to my shop vac. Surprise! The shop vac can pull it to near 80% open which means I can calibrate the MAF to the VAFM using the shop vac instead of trying to do it on a vehicle.

corax

if you are going to do all that work, you could just run a HKS VPC (Vane Pressure Converter). It's programmable and converts to a Speed Density System - no VAFM, no MAF. They're not made by HKS anymore, so you'd have to find one used.

abecedarian

and besides, I'd be more worried about that plastic, behind-the-radiator crossover tube than the AFM

Swansen

little random?? just sayin

abecedarian

that's me- random. just when everyone is going in one direction, I fork off and go another.

Swansen

yes, i think that is apparent

InternetRoadkill

You guys have no sense of adventure or curiosity. No guts, no glory.

FWIW, I already have the code for the converter half written. The only thing I'm really missing now is to take a trip to the junkyard and pick up a used MAF and its pigtail. Total expenses so far: $0.00. Can't go wrong with that.

To be honest, I don't really care if it does anything magical or not. It's just an excuse to play with the FI to see what happens.

abecedarian

Conversion from AFM sensors to MAF and MAP sensors has already been done. There actually is little to no reason to do so since the more accurate sensors offer little advantage over the factory afm sensor other than for accomodating turbo/supercharging applications up to the capabilities of the ECU, for which the AFM can already suffice. Above which, an aftermarket fuel management solution has usually already been implemented.

Swansen

Yeah, and are completely ridiculous, seriously.

Targetnut

first you need to understand that the stock head only flows about 130cfm.

Even then you'll likely find some pressure drop, and it might even go 1"hg (13.5"H2O/1/2psi) or so which will reduce peak power some, but really It's likely not to make a difference you can feel.

Now if you port the head, go with a bigger cam, and bump up the compression, You'll be increasing the flow potential and that restriction will create a bigger pressure drop and be more of a factor.

I was thinking about using a MAF, but electrically they work very different from an AFM and it was just looking to complicated. But I'm no electronic guru either.

Now I'm working on a Megasquirt. this will use a MAP sensor and eliminate any measurement device in the intake tract

abecedarian

how so, if I may ask?

Swansen

I'm not exactly sure about what you were thinking, but these are not exactly options.

https://www.yotatech.com/forums/f116...sensor-115962/

https://www.yotatech.com/forums/f116/maf-bypass-106148/

InternetRoadkill

Woot! Controller board for the converting MAF signals to VAFM signals is working nicely. Just need to scrounge a MAF from the junkyard and cross calibrate the two.