Whoa! That could be bad! Have you tried another maf or is this just something that happens on all of them? I've heard that different ones have different voltage outputs due to manufacturing inconsistencies.

 

Maybe it is a current output MAF sensor. You might need to shunt the current to ground and measure it that way.

-Mr. Wigggles

 

Sounds to me like you're pulling too much air over it, or pulling it too fast, and effectively overloading it. If this is the case, perhaps you should look into a totally different MAF, and build a small interpretive circuit to make the voltage output rang between 0 - 4V?

 

Even if you use a MAP sensor as input to the piggy-back (I have no idea if you're doing that or not) the stock ECU will still freak out without a MAF in the loop, won't it? Hmmm...I think I'm seeing why all these FI kits seem to run into a brick wall. This is logical though, isn't it? You would want to use a sensor that uses the full range of voltages across the range of expected air flow rates...suddenly you're pushing more and sure, its going to be out of range. I wonder how difficult it will be to replace the MAF and come up with workable tuning. Ugh.

jds

 

First, thanks for the update on the car........
Pricing is already looking better......
Second, How long do you think it will take to fix this problem?

 

Pricing is looking better? Yes.. it is minutely looking better....

RX8-Turbo system - $6250 $5995, 5495 = Savings of $255, $755
TSI engine management system option - $1495
Ball-bearing turbo option - $600
304SS Cat deletion pipe - $399

That brings the total cost from $8744 down to $8489, $7879. Mind you thats without tax and assuming installation will be $1000. That brings it back up to $9529 if you take advantage of the intro price....

Still kind of high for my blood thats for sure...

 

Under boost? That would be normal wouldn't it!

 

"area" that's all I have to say.

 

Some what off the subject hear but I was making a few calls and ended up talking to a Motec specialist who also specializes in rotarys. He as tested 3-4 Renisis engins on a brake dyno using the Motec 400 unit with good results. He went on to say that he was working one of the engines into a turbo set up for a race boat for a south american customer. He claims that the Motec unit works great with the Renisis and stock ECU and picks up 92% of the stock sensors and data, that's great news! He went on to say that so far the unit is providing adequate management for the turbo system. Now keep in mind that this motor has had the compression lowered and tweaked in a few other places he wasn't willing to go on about. The bad news is that the Motec unit retails for $2600-$3000 depending whare you buy it from. I was really thinking hard about doing this option and building my own turbo kit but man that's some serious coin to drop on engine management, let alone finding someone local with the experience to tune it. I also have a sneaky suspision that the other motors he was working on were for race cars of some sort. You know, those who have the cash to spend on an awsome unit like that.

 

Well said. You have obviously been typing too much on the axial thread.

 

It wasn't because I didn't want to type anymore, It is just that I wanted someone to figure out what it means.

 

Could you possibly port the maf, or put it in a bigger housing or something ... then switch to bigger injectors to balance out the equation? Then recalibrate it ...

Seen that work on certain mafs in the past ... dunno about these hotwire ones, but that's something that's done with older supras

 

I think that IS what Paul is getting at....increase the housing diameter to maintain the same velocity over the MAF, with larger actual flow. Same sensor, doesn't know it is now reading the same velocity in a larger cross-sectional AREA.

S

 

WELL put, that's EXACTLY what it means.

 

Wishing you good luck for part throttle driveability!

The ONLY way to go with respect to the OEM PCM is :
- electronicaly limit the output signal from the MAFS at its max nominal (might not even be necessary unless it gets to 5V under 2000 rpm, if I believe the manual);
- and drive the extra fuelling (and spark retard if necessary) from a MAP correction on an auxiliary ECUs (using existing or extra injectors).

This way :
- you keep things std at part throttle, including smooth driveability
- you can control the boost in open or even closed loop

Changing the MAFS area and compensating by changing injectors (higher flow rate) might work but I classify this into the 'alchemistry' section!

Remember that the characteristics of the MAFS, and the injectors (high and low fuel flow slopes, breakpoint between high and low slope, offset vs. VBatt...) are engraved in the PCM.


Regarding using Motech, it's probably very good for racing but won't give you any refinement regarding driveability. Remember all these aftermarket / racing ECUs don't feature an AIR CHARGE MODEL as in the OEM ECUs. They don't evaluate (and even predict!) the cylinder air charge in transient conditions.

With the solution I gave above, any basic aftermarket ECU would give you good control provided :
- it features a boost control strategy module
- you feed it with an appropriate signal from the e-shaft for synchro
- you install a MAP sensor
Remember that the injector firing per rev is as per an I-4 engine.

 

Do you think blowing through it is better?! I think not.

 

In a road car application, the BOV should be vented to the air intake system before the compressor (but after the MAFS).
The MAFS is precisely calibrated on a flow bench, using the full production intake system upstream of the sensor as it directly affects the flow pattern across the cross section of the MAFS. By blowing through it, the flow pattern does not correspond at all with the flow to which it was calibrated. Air charge calculation will therefore be wrong, the PCM will schedule fuel according to this wrong air charge. Expect a loss in driveability and refinement.

EDIT : Re blow through : I don't say it cannot be done. But it's a job that needs to be handled properly!

 

Isn't the MAF sensor expecting air at baro pressure? How would it know the density?? Plus ditto for a BOV. it will fuel for air that did not go in. Then of course is the housing built for pressurization? Does it messure temp before and after the compressor? I know there should be so many dia.s before and after the MAF. It's like using air stream in lab equipment there has to be undisturbed stream before and after a sensor. Even sharp edge orfice systems require a long section on each side.

Man, I wish we had Webers.

 

Actually, you must be right, there is not provision for pressure compensation in the MAFS. Another good reason to keep it upstream of everything FI.
BOV outlet should be redirected between the MAFS and compressor.
The air temp is measured at the MAFS too.
And indeed, you need to make sure that the air flow remain more or less laminar even after the MAFS.

 

I was browsing through the manuals for the eManage (aka Canzoomer) and they suggest adding their pressure sensor into the loop if you exceed the capacity of the factory air flow meter or MAP sensor. The pressure sensor can then be used for the scale of each Map table.

More info

 

*bump*

Any news?

 

How about the problems guys, have things gotten straightened out yet? I was just wondering when we could expect numbers. I know nothing about turbo's but I am interested in getting a kit for the 8. Just an update is all that we need but surely numbers must be close.

 

Sorry.. no new news.. they are still working everything out...

but whats up with SSR's site?

strange....

http://www.ssr-engineering.com/

 

Maybe they're retooling. I hope they didn't go out of business.