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Discussion Starter #1
It's been a while since I've been here--flirted with buying a Honda (blasphemy, I know. . .). I'm amazed to see how much this place has grown!

OK. I'm thinking of doing IRTB's on my 91. No money for Fuji's or Chikara's. A GSX-R or something similar option seems to be my best bet. Engine management is the next hurdle. I'd be thinking Megasquirt in the long run--again, I'm cheap--but I had a thought. If I were to fab a plenum that has an appropriate sized round tube heading to it, could I attach the OE or a RX-7 AFM to it and run the IRTBs on the stock computer to start out with? I know, why do the IRTB's if you put a plenum and a restrictive AFM, but I'm thinking of getting one thing sorted before I go to the next--to eliminate variables when the inevitable issues arise. Is this stupid? Is this feasible? I already have the RX-7 AFM in the garage to handle the higher flow of the IRTBs if I need it. Thanks in advance for the help!
 

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yes you could do that. I think it's more work than is worth it, unless you intend to run a plenum in the long run.
 

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Discussion Starter #4
Nah. I just feel like fabbing a plenum would be easier than tuning a Megasquirt (for me, at least) and I don't want to be off the road for too long. It's gonna be a few months anyhow, gotta raise funds for a new clutch/flywheel before I do anything--clutch died after my first autocross on r-compounds :)
 

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Mufasa in Training
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What Taylor said. Who's to say that the factory AFM will give you the correct tuning for the car to run in optimal condition. Even then, you probably wouldn't see the benefits of all of the time and money you spent, IMHO.
 

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OR you can go over to the megasquirt board and read about setting up megasquirt for miatas. its not that bad, there are tons of maps to gank and there is a whole thread about different ITB's that you can read up on.

most guys problem have centered around the tps voltages from the various motorcycle brands.

it can be and has been done, you can do it, and if your crafty you can do it for really cheap.

my 2c? if your serious, build a megasquirt or get another standalone, tune it to run off of map sensor and ditch the afm, at that point 75% of the hard work is finished on the itb front. you want to go itb you really only have to sort out the tps, then the plenum is give or take.
 

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most guys problem have centered around the tps voltages from the various motorcycle brands.
You dont even need a TPS input to run Megasquirt. I have ran my Miata for 3 months without one. I have the dummy ON/OFF 1.6 TPS sensor.
see I never did it I was just reading various motorcycle itb setups, they were trying to use the honda/suzuki/etc tps sensor on the itbs and having issues figureing out what voltages etc. if you can run it without a tps sensor and have it running good then thats even better I suppose!
 

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Best bet is to blend TPS and MAP. People will tell you it'll run just fine w/o TPS but it's so much easier to get it to run fine if you blend both. Mapping TPS voltage is simple piece of cake if you're installing aftermarket open source EFI computer. Honda guys have it so easy. They can use Honda motorcycle throttle bodies on their DIY ITBs and feed the signal straight to their cracked oem computer with no problem.
 

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Hey steamcorners,

I have an answer to your hypothetical question. Lookie at my sign off below for a quick peek at: "The whole system is based around 2004-2005 Suzuki GSX-R 600 38mm throttle bodies."

My story here: http://www.clubroadster.net/forum/viewtopic.php?t=3615
and within that you will find the coolio who made the system, story too.

Im still struggling with the ECU issue but it looks more and more Ill be MegSquirting too.

Oh yah, you can see a clip of them running on my photobucket site.

Password = fast

http://s8.photobucket.com/albums/a48/Aestheticsphd/


No doubt about it IRTBs are a way of life, a passion for growling throttle response vs a bolt on turbo or SC.

Good luck whatever route you choose to go.

Speedwell,

FH
 

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