anyone running w/out stock AFM

[BAHKACK]

I'd like to do a cold side w/ MegaSquirt on an NA w/out stock AFM.

Any issues? Advantages?

thanks

[BAHKACK]

I had not done my homework. All new intake? Thats cool. What happens with the AFM? Sorry for newbie questions. Looks just too good to be true, I am excited.

[pace]

Hi there!

Tom gave me a heads-up about this thread and asked if I would chime-in.

I'm running the FFS coldside setup, minus the E-cool, with the DIYAutoTune.com MegaSquirt PnP on my '95 NA.

To answer your specific question: The MSPnP has a built-in MAP sensor. You will need to T the supplied line into the boost reference that comes off the FFS manifold. The MegaSquirt can then be configured to either run with the stock MAF for intake air temperature reference, or with an external IAT sensor that can be purchased from DIYAutoTune.com (it can easily be sourced elsewhere too).

I ran the MegaSquirt for several weeks prior to the FFS coldside installation, in order to familiarize myself with the unit and to see if I could easily establish a stable tune. The stock DIYAutoTune.com tune is very good right out of the box. I chose to run with the stock MAF initially. When I installed the FFS coldside kit, I tapped the FFS intake manifold and installed the external IAT sensor. This allows you to completely remove the MAF - so you will need to find some other way to attach Tom's intake hose to his air filter (hint: a piece of the stock plastic crossover tube can be cut for this purpose). The external IAT must be spliced into the factory MAF harness, and you must reflash your MegaSquirt with different firmware and load a different basemap. This is because the IAT correction tables in the firmware differ based on the type of IAT sensor being employed (stock MAF versus external GM sensor).

As for observations.. The MS IAT correction tables seem to assume a n/a setup that would not see the extremes of manifold intake temps that you can easily attain with a non-intercooled FFS coldside. Remember, I have no E-cool and have not yet installed my water-injection setup. When the FFS manifold heatsoaks, the MS IAT tables apply a little too much negative fuel correction, causing some lean conditions. In my car, this manifested itself as pinging under load during the onset of boost, primarily between 3k and 4k rpms. If I tuned for the heatsoaked condition, I'd be extremely rich when the motor was cool.

The solution is either to stop that IAT sensor from heatsoaking, or modify the MS IAT correction tables. I modified the tables, and recompiled the MS firmware. It seems to have mostly addressed the issue, although not entirely. I believe that the WI will quell remaining heatsoak issues, but for now I'm just careful not to lug the motor when it's heatsoaked. The 'lean when heatsoaked' problem can also manifest itself as a lean idle, causing oscillation of RPMs around the target idle. The MS has pretty sophisticated (and touchy) idle control, and there are a few tricks that you can use to tune out this condition also. And modifying the IAT tables probably helps there too. After several weeks of occasional fiddling, I have finally gotten my idle as stable as it was when running the MS prior to the FFS coldside installation. I'd say idle quality is about 90% of what it was stock.

As a general observation, I'll say that the majority of FFS coldside owners will be happier running the PC Pro that Tom supplies with the kit. It'll likely make more power out of the box than an MS setup, not least because of the intercooling achieved with the E-cool system. However, the MS will allow you to run larger injectors, water-injection, nitrous, etc. and will provide a finer grained level of control over your vehicle tune, including full timing control. If you're a tweaker like me, then it's fun. For many people, however the issues I have worked through would be rather intimidating. And I should note that my Miata is not my only means of transportation - if something goes wrong I have a backup vehicle to get me to work.

If you decide to go the MS route, then I can certainly try to offer assistance when you encounter the issues that I have. This is the second time I've run an aftermarket standalone (I previously ran a WRXLink on my Subaru) and I will say that it's a better quality product with a much better support base than I experienced with the Link.

Oh.. and you should plan on either buying a wideband O2 sensor and taking a crash course in engine tuning, or else drive straight to your nearest dyno tuner after installing the FFS with the MS. I found the MS basemap to be relatively rich under boost, but still I babied the car until I could get it on a dyno. You take your chances if you choose not to do that - your car may run lean on the MS basemap.

Hope that helps.

-James

[BAHKACK]

pace,

Thank you for your comprehensive reply.
No disrespect to the standard kit (it is easy and better suited to my limited skills/understanding -I may still go that way) but I do see the logic in your approach. I am not geared for tuning, but my father-in-law is, and I will be depending on him.
I lack some fundamental understanding, so a few more basic questions...
Will water injection cool the charge (or just reduce detonation?) as well as (better than?) E-cool?
Will more power eventually be available with your approach? Too soon to tell?
The approach of removing the MAF + WI and perhaps going with larger injectors is to replace the "band-aid" approach of the 5th injector? I really don't like saying it that way because E-cool could be seen an elegant way to fix two problems at one time (charge cooling and insufficient fuel volume). But your way seems to correct the stock cars inherent problems(?). I am a little nervous of unbalanced AF with 5th injector (not sure if I should be).

If this works, perhaps Tom and the MS guys could collaborate on a stage 2 kit?

[pace]

pace,

Thank you for your comprehensive reply.
No disrespect to the standard kit (it is easy and better suited to my limited skills/understanding -I may still go that way) but I do see the logic in your approach. I am not geared for tuning, but my father-in-law is, and I will be depending on him.
I lack some fundamental understanding, so a few more basic questions...
Will water injection cool the charge (or just reduce detonation?) as well as (better than?) E-cool?
Will more power eventually be available with your approach? Too soon to tell?
The approach of removing the MAF + WI and perhaps going with larger injectors is to replace the "band-aid" approach of the 5th injector? I really don't like saying it that way because E-cool could be seen an elegant way to fix two problems at one time (charge cooling and insufficient fuel volume). But your way seems to correct the stock cars inherent problems(?). I am a little nervous of unbalanced AF with 5th injector (not sure if I should be).

If this works, perhaps Tom and the MS guys could collaborate on a stage 2 kit?

I don't really view Tom's 5th injector / E-Cool system as a band-aid, as it really is a rather clever way of both adding additional fueling and cooling the intake charge. I don't think there is a simpler, more cost effective way of making ~200WHP with a supercharger. It's hard to see any significant downsides to this setup, within the context of his stated power goals. I can't speak to unbalanced AFRs with the 5th injector, but WI would likely suffer similar distribution problems if they exist since it mists at the same location under the blower discharge outlet.

Regarding your other question; water does have a much higher latent heat of evaporation than gasoline, and will thus have the potential to cool the intake charge to a greater degree. However, in the absence of E-Cool you're going to have to run larger injectors (I'm running 460cc RX-7 injectors). And water injection kits can get pretty darn pricey too - I'm doing a DIY setup, but it has a limitation in that it implements a simple on-off with no progressive control of flow rate. That means that I won't start misting until some relatively high boost threshold (say, 9psig) and therefore the majority of the time I'll not be achieving any intercooling. Of course, I could set the WI to activate at a lower boost threshold, but then it's going to consume water at an impractical rate. The more sophisticated systems from Aquamist and Snow Performance can provide a variable flow rate based on boost reference, but as I said those kits get very expensive. My plan was to see how this setup works, and if the results are promising I'll possibly upgrade later.

I believe that ultimately the MS and WI setup should be able to provide more power, but that comes at a higher cost and probably a compromise in driveability. Right now, I believe I'm making no more power than I would with an E-Cool setup because in the absence of any intercooling we had to run the AFRs rather rich (11:1) with conservative timing, in order to keep detonation at bay.

Once I have the WI install completed, I'll post comparison dyno charts. I am hoping I pick up 20-30WHP right off the bat. I guess it will depend in part what % of methanol we run.

Oh.. and I do believe that the MAF is a significant restriction. I've heard wildly varying numbers as to the gains realized by removing it, but regardless the general consensus seems to be that removing it is a 'good thing'.

-James

[pace]

Btw.. the reason I haven't yet completed the WI setup is because DIYAutoTune.com do not yet have the third (accessory) harnesses available for the MS PnP. I last checked with them a couple of weeks ago, and they told me "very soon".

So my hope is to have the installation completed and the car back on the dyno within a month. Worst case, I can control the WI using a simple pressure switch referenced from the boost signal.

[BAHKACK]

I am glad/grateful that you are doing your system now, as your experience will help set my course.
My miata is replacing an '65 E-type jaguar (GTJ built motor) AND a '65 Mini Cooper 'S' so even with MS and WI I will be $ ahead (my wife dictated this move).
Another possibility... could I use E-cool and still dump the MAF? If I went that route would I need MS?
In any event I will be using the FFS kit in one form or another (ruled out the FM, Moss, and MOAB kits). FFS advantages of cold side, short intake and 18lbs weight wins for me.
Thanks again.

[pace]

I don't think you'll be able to ditch the MAF sensor with a piggyback computer like the PC-Pro. However, I will investigate whether it would be possible to control the 5th E-Cool injector with the MS. I've been curious about that myself..

Btw, we installed the solenoid for the WI setup on Sunday evening. Also routed all the hosing, and installed the Aquamist nozzle. We put the nozzle in the forward-most boost-reference port on the FFS manifold, and T'd the line that was previously referencing there (the MegaSquirt MAP sensor and boost gauge) into the adjacent bypass actuator hose. I think this location is as optimal for the WI as the 5th injector port, which was a little more tricky for us to deal with (drilling and tapping a bolt for the WI nozzle would result in the nozzle sitting rather far back out of the manifold due to the manifold wall thickness at that point).

All that is left to do now for the WI, is to install the 2.5 gallon tank in the trunk (arrives on Thursday), then hook up all the wiring. I also still need the MS accessory harness from DIYAutoTune.com

I will post pictures of the WI install when it is complete. Also dynocharts.

[kudotaku]

Running a FFS coldside with a standalone is something that Ive been thinking about doing. I currently have an AEM EMS running on my car with a MAP and IAT sensor but I wanted to get the FFS without electronics and see what I could do with the standalone. I too was wondering if Tom ever considered a standalone option for his kits. Since the AEM does have auxiliary injector maps, I was thinking that I can run the E-Cool injector with the AEM. Things would be much easier if I could know a rough duty cycle/load graph of the injector used for the E-cool. Want to help me out Tom? I think the coldside with E-cool with a standalone would work well and I dont think it would cost that much more than running two PC-Pros.