stock fwd beams 3sge dyno results

[Alchemist]

Stock ECU

[urantia]

well then alch, thats a dam nice effort on stock ECU! i'm impressed!

Roman, there is a guy by the name of billzilla around here that glued a bunch of straws together and inserted it into his intake piping. This straighened the air out so to speak. And apparently smoothed things out quite abit.

[Roman]

That's actually quite a clever idea regarding the straws!

I might just bite the bullet and get a standard airbox though. *Anticipates financial ownage from Toyota*

[Alchemist]

That's actually quite a clever idea regarding the straws!

I might just bite the bullet and get a standard airbox though. *Anticipates financial ownage from Toyota*

Got lube?

Also, thanks urantia, was a fun car to drive

[aw11man]

This probably wont work, never tried it b4

[urantia]

Didnt work, but there is a pic of some nice boobies half way down the page.

[AndyTTR]

when i first installed my engine it was idling like you described before. worked out in the end that i'd put the vacuum lines for the charcoal cannister on the wrong way around - after fixing this it was fine. It also used to idle eratically after using the a/c but since i pulled the ISC out and cleaned it up that problem also seems to have disappeared. Having no way to manually adjust the idle speed is a bit of a bugger.

Im using the stock m/t ecu, but it uses a map sensor. I wonder why they went back to AFM on the gen 4?

Have you had a look around a toyota wrecker? When it comes to sensors and airboxes I've found that there's usually something from another local model around the same era that'll have the same /similar components.

I've got a set of extractors waiting to go on - I saw some identical ones on yahoo auctions once and they said they were made by RSR (or similar?). They're for a ST202 but im sure they could be modded to fit an MR2. You'd just have to cut them off at the flex join and fit up something appropriate.

[Roman]

I think the reason they use a MAF (hot wire mass air flow) sensor, is that it can compensate to a certain extent for volumetric efficiency mods done to the engine.

A MAP sensor engine makes an assumption about the airflow based on throttle position, MAP sensor reading and the VE of the engine, whereas a hotwire airflow meter samples the amount of air coming in directly. If the VE of the engine changes, so does the amount of air coming in.
You cant pick this up with a MAP sensor, IIRC. (Or to a lesser extent, anyway)

I think they made a bit of a jump in ECU technology with the gen 4/5, I've heard stories of Altezza guys fitting SAFCs, and having the ECU recompensate for them, so it ends up back to normal after about a week.

It's also interesting to note, that I've heard from many different sources that an engine doesnt use the sensors (IE oxy sensor and AFM) when it's running at WOT, as it has a map which it uses at WOT or >75% throttle...

I can confirm this is not true, for my engine at least!
I had my intake pipe come off at WOT, *cough* the engine completely shut down, and wouldnt start without air flowing through the pipe again.

[JustCallMeOrlando]

I'd say the change was made for emissions. MAF is more accurate.

[AndyTTR]

So is the airflow meter on the Gen 4 the hot wire type or the flap type? I cant work it out from the pictures?

You're right about the MAP sensor not being accurate if its not calibrated correctly. There's a bit of black magic involved in calculating airflow using absolute pressure. I think if you modify the volume of the plenum then the computer just gets confused and makes wrong assumptions about the flowrate? The benefit of the hot wire is that, like you said, it can directly measure the volume of the air. I've been told that they're generally avoided on high performance engines because they respond slower than the MAP and flap type?

Im pretty sure the ECU from 1994 onwards is a Bosch Jetronic D type, I remember reading that somewhere... The way its programmed is probably better with each new engine revision though.

There's different ways of mapping ECUs. If it wants to run in closed loop mode (like you were saying with it automatically recalibrating itself) then it will need the information from the O2 (wideband?) sensor, AFM etc. If its running open loop (non learning mode) then it can be mapped directly to throttle position, load, airflow etc. Factory computers do a bit from column A and a bit from column B depending on the type of driving.

Could you jig up the hot wire setup / airbox from a nissan to work instead of getting raped by toyota?

[Roman]

Yeah, I think the gen 4 ecu is probably a bit different... part of the reason that it's stupidly expensive to get an aftermarket ECU that can work as well as the factory one.

Not many ECUs that I've found like controlling 4 injectors, 4 coil packs, VVTI and crank angle/cam angle sensors all seperately.

You cant run the 3SGE coil packs in wasted spark, as apparently they overheat at higher rpms if you do.

And I wouldnt want to run batch fired injectors, that's just... wrong.

The only sensible options for running a VVTI engine that I've found, are:

motec
powerFC for altezza
modified powerfc to suit single VVTI engine
c-one ECU.

And apparently the new link ECU can run VVTI etc, but I've yet to find more details on it.

I should be able to get an airbox to suit from the wreckers, there's quite a few GT caldinas on the roads, and will definitely be cheaper than going direct to toyota.

[AndyTTR]

haha, damn you kiwis with your exotic cars!

[JustCallMeOrlando]

Autronic would also suit it Roman.

[kanazai2001]

The PITA thing about the beams airflow meter, is that it looks like this:



and often doesnt come in the pipe that it should. (Which is what happened to me)

The factory Caldina ariflow meter is positioned here:



You can see that it's in the first part of straight pipe, just after the airbox.
I wonder if the airbox helps dampen any pulses or reverberations that might upset the reading that it gets?

Here's my setup:







My engine was converted to a MAP sensor when I got it, so I had to buy the AFM, and then mount it in the pipe that was included.

Rom,
im having a red beams in my FF silly kar, im curious to know how to convert it MAF to MAP without change the ori ECU...
you have mentioned that your red beams was converted to MAP, may i know was it using the ori ECU with MAP or aftermarket ECU with MAP before you convert it back to MAF?!

[Roman]

Update!

I went back to the dyno to get the MR2 dynoed after fixing a few things.
It's definitely running better, but still not 100%.

Still running stupidly lean, and my AFR is a bit FUBAR :?

Plans from here are to ditch the standard catalytic converter and muffler, and replace the pod filter with the standard airbox. (Only because of the farking AFM that shits itself when you mod/replace the intake pipe)

Current mods are apexi pod filter, HKS aluminium intake pipe modified to fit MAF sensor, and TOMS extractors with heatwrap.

This engine is an 'automatic' one from an ST202 celica, which apparently makes 10hp less than the manual ones. I'm not sure if it's a physical difference, maybe in cam profile etc, or if it's just the ECU.
I'm running the MR2 M/T ECU though.