Brain teaser for superchargers

[chiefmg]

Those of you with intercooled superchargers know the joys of idle droop, at least on occasion. General consensus from what I have gathered is the IAC can't adjust for the increased volume of air in the system compared to stock. Some people are able to tune it out if they have a MS or similar, some use dual throttle bodies, and the rest just live with it.

My brain sometimes works, and I have been asking myself what would happen if one were to use an IAC from a car with a larger air volume in the intake system. Say, something with a larger engine or a factory turbo system. I'm still getting up to speed on modern induction and fueling systems, but it seems that with an engine computer that can be programmed to allow for different parameters, and with an IAC that is compatible that you could conceivably end up with a solid idle with no extra pieces required.

Anyone who has more experience than I with engine management (pretty much everyone) please speak up and air your opinions/thoughts on this. I have been doing the small amount of research I can while at work (basically looking at IACs from different cars to see if they might fit), and unless told that it absolutely won't work based on previous attempts, I am going to give it a shot when I get home.

[maharaj]

Couldn't you just add a chip to the computer and program it to the specs of the car?

[chiefmg]

You don't chip an MS, that's where the programming part of my statement comes in. The IAC is basically a sensor and as such is designed to work only over a specific range. By introducing an intercooler you step outside that range. I am sure if you were good at that sort of thing you could come up with an algorithm or some such to use to program with and get the stocker to work, but my abilities in that direction are sorely lacking.

[— Agent☣Orange —]

Interesting direction with this topic but my first reaction is where are you going to find a different IAC that will work on the Miata throttle body? Even if you found a bigger IAC, there are still the two small, square passages on the TB to mate it to.

I suppose you could remote mount a different IAC but I still don't see that coming close to addressing the volume of air between the TB mounted on the back of the SC and the intake manifold, even worse when you add an intercooler into the mix.

The IAC is only designed to make small adjustments to small amounts of air entering the TB in order to maintain idle, not handle huge amounts air in a modified intake tract. Add an intercooler and it becomes even less feasible or realistic.

Maybe I'm just overthinking this or just not experienced enough but it seems the number of vaiables to figure from scratch is daunting whereas the dual-throttle body setup is so much simpler, cheaper and more reliable to do.

[chiefmg]

Interesting direction with this topic but my first reaction is where are you going to find a different IAC that will work on the Miata throttle body? Even if you found a bigger IAC, there are still the two small, square passages on the TB to mate it to.

I suppose you could remote mount a different IAC but I still don't see that coming close to addressing the volume of air between the TB mounted on the back of the SC and the intake manifold, even worse when you add an intercooler into the mix.

The IAC is only designed to make small adjustments to small amounts of air entering the TB in order to maintain idle, not handle huge amounts air in a modified intake tract. Add an intercooler and it becomes even less feasible or realistic.

Maybe I'm just overthinking this or just not experienced enough but it seems the number of vaiables to figure from scratch is daunting whereas the dual-throttle body setup is so much simpler, cheaper and more reliable to do.

I have already considered the passages in the throttle body being a bottleneck, if that is the case then I would have to look at mounting the other throttle body that the IAC came attached to. Yes there are variables, I am going to try to minimize those by using a Mazda part if I can. Not looking to make life too complicated so no remote mountings.

Alex, the reason I started this thread was to see if we can shift the paradigm. In all the reading I have done I have never seen anyone bring up this particular modification. I have been leaning towards DTB if I can't get the droop tuned out with the MS, but since I have lots of time here at sea I let my mind wander and this is what came up. If nothing else the information will now be on the web so people won't wonder in the future.

[cjsafski]

Dual throttles ftw

[gapmiatas]

I relocated mine to the firewall but can't find the kit that I used... fixed all idle droop issues completely.

[— Agent☣Orange —]

I've installed a couple of those before but they were for cold-side MP62s from Fast Forward Superchargers. Since those were an integrated SC/intake manifold, idle dip wasn't really an issue to begin with.

I hesitate to say this setup would work with a hot side with intercooler though but if you want to give that remote IAC a try like above, give Tom at Fast Forward Superchargers a call to get the kit. I couldn't recommend a nicer person.

[Demon I Am]

Tom is a great guy, for sure!

[chiefmg]

That's interesting. Wouldn't be too hard to fabricate the mount, it could be put anywhere there was space. Do you have an intercooler? I can see mounting the IAC that way removes the extra volume of the supercharger setup out of the equation. But would that be enough for an intercooled system?

[chiefmg]

This is still on my mind, I haven't been able to make it to the junkyard as yet between the holidays, weather and a cold.

[Cxmoney]

Damn man. I bought a intercooled mp62 supercharger kit and the more i read, the more difficult the install seems to be. I am honestly even at the point to where i am thinking about selling it, and ive only had it a month and havent even seen it myself yet! Haha. Just seems like more trouble than its worth... My car likes being NA anyways...

[wannafbody]

What about a TB from a Mazdaspeed turbo?

[chiefmg]

Don't know, it might be a possibility. Price on one would probably be through the roof though. Weather is warming some here, if we don't get any more precipitation in the next few days I'll try to hit the junkyard.

[chiefmg]

While putting things back together today I pulled the IAC and traced out its footprint so I'll have something to go by at the junkyard.