Hey guys, just wondering about the viability of ITB's on 6g74's. I've found a seller of two sets of ITB's (originally from a large displacement motorcycle), and I'm wondering if it would be worth chopping up a stock top manifold and getting them to fit in?

I mean, if a streetfighter costs $1k, and a pair of ITB's cost $400 AUD for ITB's + shipping, it wouldn't really be that expensive to mod them to fit.

But the main question is begging to be asked: Would there be much of a performance boost in doing so, either with a stockie engine, or a high comp one?

What about the problem this will create with the MAF air flow sensor.

Using ITB's you would need a full aftermarket ECU not just a piggyback. And it would only really suit a high comp Hi revving N/A application.

Plus you will need to find a way to link them all together to open them all at once.

Alot of work > not much gain

it depends on how much the stock ecu relies on the TPS (i think they depend on them a fair bit).. that is pretty much all you will need to worry about.. being AFM (MAF) you shouldn't really have any drama's with that.. as all the air will be coming through that anyway.. much like the stock 20 year old setup on a 20valve 4age toyota.. just need a sealed airbox to run over the throttles..

basically you will need some sort of piggy back at the least to be able to manipulate the signal from the TPS.. as 15% throttle over 6 throttle bodies would be more like 40-50% on the stock single TB.. which is just begging the the ECU to have a heart attack..

there are heaps of engines you can throw quads on and just turn key start.. 4age map sensored being one of them.. http://www.youtube.com/watch?v=gkZnYs-HPA0 that was on the stock ecu.. they don't really rely on the TPS.. you can unplug them and drive no worries.. but as a fail safe they run a bit rich..

you can beat the induction noise from ITB's... so i reckon you should do it!! :) be worth doing some sort of cams, higher compression though.. might not be so benificial other wise..

this is after it was all tuned, with an Adaptronic using a RPM vs TPS tune only.. (no afm, or map sensor)

http://www.youtube.com/watch?v=HbI3VNIHUgo
http://www.youtube.com/watch?v=ffwlnCpwMDw

it's common to see ppl use GSXR throttles.. as they are silicon/rubber joiners.. and you just need to 'modify' the tabs between them (to actuate the shaft), and balance them..

http://lander.tuning.cz/images/swiftkc/itb1.jpg

Performance gain from individual throttles depends on how much you are prepared to spend to do it correctly, and then map correctly. If the stock manifold is well designed there may not be much gain at all, except for much better throttle response. That though can make them painful to drive around the city as the engine gets very jerky. Most cars with individual throttles have gone to electronic throttle control to help with this. Some bikes have too.

Generally the perceived gain when going to individual throttles is more to do with the shorter inlet tract improving high rpm power. However you lose out down in the mid-range where you really need it in a heavy car with small engine like the Magna. The stock manifold has long runners to boost power where most people need it.

Cheers,
Alan

What Alan said is true.. even with my tickled up 4AG, it was pretty useless if you put your foot down.. you will learn throttle control.. eg half throttle to get it off the line, to keep the air speed up etc etc..

Haven't RPW already built an ITB manifold? they call it the six-pack or something like that.

Mine away good sir..

SuFz

Hah. There's a current itb thread going.. Should have posted in there?

OOoooo an old one!


*Checks for zombies then quickly leaves thread*

At least someone's using search!