also my other question is, my current stock tb has the iacv block off plate and coolant bypass.. does it really matter if i get the b16a/b18c2 or ITR tb? i just noticed itr variants cost a bit more and have the iacv built in which i won't use anyway?
Originally Posted by Slow96GSR
If 1 person has had bad luck with a product don’t condemn it until you yourself have tested it. Now if 10 pros have tried it and it sucked then I would trust their opinion.
also my other question is, my current stock tb has the iacv block off plate and coolant bypass.. does it really matter if i get the b16a/b18c2 or ITR tb? i just noticed itr variants cost a bit more and have the iacv built in which i won't use anyway?
i have no issues with the idle at all.. the 62mm isnt overly huge so it seems ok with the skunk im. i got the itr tb.
b18c2 the earlier models have that built in iacv ur talking about.. i know there's been issues with idles and shit like that.. rpm raise n dropping. my mate had exact same issues.
he wasrunning a b18c2 with a older model b18c2 tb with that built in iavc.. now changed it to the same tb that it was meant to be running no issues.
if that makes ssense?
i know a friend is using a 68mm on his itr and has dramas with idle and cold starts.. pain in the ass..
yours/fatboyz setup is what got me intrigued... basically same setup except for CR and IM+TB.... i'm trying to account for the missing 5-7wkw across the rpm band and the 16wkw difference in peak
also if yous is 70mm.. what is the ID of the intake mani your using? ITR 64/62mm?
Last edited by dsp26; 23-09-2008 at 10:19 AM.
Originally Posted by Slow96GSR
If 1 person has had bad luck with a product don’t condemn it until you yourself have tested it. Now if 10 pros have tried it and it sucked then I would trust their opinion.
Dupac, what you mean by iacv built onto the b18c2 tb, Do you mean the Fitv?
You guys reckon it should be fine using a 68mm Tb with out porting my IM? IM currently at 64mm.
I understand how this all works now after a total of 5hrs continuous research on the physics and why bensons/fatboyz 70mm Tb works with the 64mm ITR IM....
you don't match TB size to IM inlet size.. you match TB size to the plenum volume..... but in their case its working like a taper anyway.. minus maybe some turbulance cause by a flat 'lip' on the IM due to it being smaller than the TB
Originally Posted by MichaelDelaney @TeamIntegra
the low rod ratio of our Tegs already causes the piston speeds to be optimized for cylinder filling during the intake stroke at low-mid rpms. So if you already are having enough suck at low rpms an oversized TB bore will just make that more apparent. But as rpms increase, the time spent in the intake stroke shortens. Our low rod ratio and the pistons speeds away from TDC don't help cylinder filling under these conditions. The low rod ratio engine needs help filling at high rpms from ram air and scavenging. You need good flow speeds out of the IM plenum and down to the head to create the ram air. If the TB is too big, the flow speed dies. Couple that with a shorter fill time and a big TB bore just kills filling at the top rpms where you need it the most for low ets.
This isn't theory. People have theorized it and then shown this theory to be true in real life.
You have to understand how the engine parts work together: rod ratio, cam spec, port size, IM plenum volume and runner dimensions, and TB bore. They are all connected. Each one determines the other's size. They inter-relate. They all center around where your powerband
should be placed along your rpm range.
Originally Posted by Slow96GSR
If 1 person has had bad luck with a product don’t condemn it until you yourself have tested it. Now if 10 pros have tried it and it sucked then I would trust their opinion.
im going to be using a ITR manifold with a obx 68mm TB... because i got nthe tb cheap... we will see how i goo that might be a month or two away
let us know how it goes....
you gonna dyno after and overlay to your current?
i just ordered a 65mm coz it came with a free block off plate for whatever it is at the bottom of the tb (fitv/iacv..)
Would've loved to get this hyped one though... 68mm tapered to 65mm at the plenum.. worked out to be ~AU$210shipped
also found a 72mm tapered to 65mm with a free brand new oem tps already bolted and calibrated for ~AU$230 shipped
Originally Posted by Slow96GSR
If 1 person has had bad luck with a product don’t condemn it until you yourself have tested it. Now if 10 pros have tried it and it sucked then I would trust their opinion.
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Originally Posted by dupac->
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