Greddy/BEGi-S vs. ITBs
#45
Boost Czar
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not the cast iron guys, if they do Corky wants you to send to him, he'll repair them and send them back out. but i don't think he's seen more than one or two of his cracked.
#46
Boost Pope
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Ironically, that's exactly how my SV650 is set up. There are two throttle plates in each barrel- one mechanically linked to the grip, and a second one controlled by a stepper motor driven by the ECU. The bike obviously doesn't have flowmeters or MAP- just TPS, baro, and temperature. It is an astoundingly smooth and responsive engine. Not nearly as powerful as a GSX of equivalent displacement, but the torque "curve" is damn near a horizontal line from 3,000 to 10,000.
#49
You are asking that question on a turbo board and I am pretty sure you'll get votes for an itb setup. obviously, i am being facetious.
I've got an itb setup and I do love the throttle response. I tracked the car a weekend or two ago and I was amazed with the throttle response. I was revving the 1.6 all the way to 8000rpm and waiting for it to blowup but it didnt...lol...An itb setup will involve more work and money. I've got my next project going that involves a 99 head mated to an 01 shortblock. I wont be staying with the 1.6 much longer. Money is money and if you have it, youll spend it.
My last band aid to get power is forced induction....i would probably plumb a turbo with my itb setup.
I've got an itb setup and I do love the throttle response. I tracked the car a weekend or two ago and I was amazed with the throttle response. I was revving the 1.6 all the way to 8000rpm and waiting for it to blowup but it didnt...lol...An itb setup will involve more work and money. I've got my next project going that involves a 99 head mated to an 01 shortblock. I wont be staying with the 1.6 much longer. Money is money and if you have it, youll spend it.
My last band aid to get power is forced induction....i would probably plumb a turbo with my itb setup.
If I was building a 1000hp+ turbo road race motor, had an unlimited budget and was restricted to 1.6L I would definately be looking at ITBs. But mainly for off boost throttle response, and becasue with the unlimited budget the entire motor would be blueprinted to completely new specs and need to match the cam and exhaust manifold.
For what they are and what they get the factory manifold has proven to be more than adequate, and capapable of producing more power NA in CSP trim, and at the levels most of us intend to play at.
I'd like to see empirical data on your part to prove your statement that I WON'T receive benefit from it.
Some evidence based statements from posters on this board would certainly be a treat for me.
Some evidence based statements from posters on this board would certainly be a treat for me.
So go ahead and start proving to us that there is actual benefit to ITBs on a turbo miata.
#50
Ironically, that's exactly how my SV650 is set up. There are two throttle plates in each barrel- one mechanically linked to the grip, and a second one controlled by a stepper motor driven by the ECU. The bike obviously doesn't have flowmeters or MAP- just TPS, baro, and temperature. It is an astoundingly smooth and responsive engine. Not nearly as powerful as a GSX of equivalent displacement, but the torque "curve" is damn near a horizontal line from 3,000 to 10,000.
Im not after a dyno queen that will crank out x amount horsepower and torque. Im after a well balanced driving car that I can abuse on the track.
I dont mind exotic setups and I dont mind performing experiments to backup claims.
#51
Ironically, that's exactly how my SV650 is set up. There are two throttle plates in each barrel- one mechanically linked to the grip, and a second one controlled by a stepper motor driven by the ECU. The bike obviously doesn't have flowmeters or MAP- just TPS, baro, and temperature. It is an astoundingly smooth and responsive engine. Not nearly as powerful as a GSX of equivalent displacement, but the torque "curve" is damn near a horizontal line from 3,000 to 10,000.
But there's a lot to be said for intake manifold design. Telling yourself it doesn't matter is giving up a lot. It might not be worth the trouble, but it would buy you something, I'm sure of it. Who here hasn't seen where they'll put a leaner injector in one cylender from the factory because the manifold sucks? Only with modern CAD and/or lots of flowbenching can you get it right. In fact, that's how you make a manifold, you flow bench it with individual flow meters on each port. Then you look at how it changes with RPM (which is tied to the cams and to manifold pressure, humidity, etc) and you choose the best compromise, after deciding if you want a maxium horsepower peak or a flatter torque curve.
Adjusting those factors individually would help. Just run of the mill ITB's would only let you make up for deficiencies in the manifold design. But independently operated ones would completely let you maintain even flow across all cylenders at all times. Like the SV, you could have your total flow throttle in the front, and just a small adjustable restriction on the inlets.
So, someone talk Joe into letting me drive his bike. :-) Maybe I'll let him drive mine but then he'll rave twice as much about how much better the system is.
#56
Boost Pope
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So, someone talk Joe into letting me drive his bike. :-) Maybe I'll let him drive mine but then he'll rave twice as much about how much better the system is.
But it is tempting.
#57
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You should ride it. It's not nearly as comfortable as your SV, but so much more powerful. I had a GSXR750 for a while, and while I decided that it wasn't for me, I'm glad that I got the chance to pilot it for a while.
#58
Like you said, if the stepper motor decides to crap out while wide open, I can still close the plates that matter. It'd be an interesting experiment though to disconnect the motor and open the secondaries up, then see how it rides. I'm sure the bike would throw a CEL though. (what an odd concept...)
But it is tempting.
But it is tempting.
Anyway, that's down for a carb-change that never happened, but if this miata works out I think I'll microsquirt it. It'd be weird to have boost control on there, but it would be very useful! I always figured the gsx-r750 would be about an ultimate bike. Then again, I've ridden some modern sport-600s and the lack of torque till 50,000 rpm is kinda weird. But it's hard to imagine the 750 isn't at least ok.
Anyway, I'd be really curious to know how it runs that way. Let me know.