kpr

pretty sure old mate @Roman set his up like that. but was still some kind of issue not making it ideal for street use? need 8 injector drives setup as staged, whilst also being able to adjust the injector timing. so the fuel makes it down the hole at correct time without getting thrown out. no drama's for ecu's these days. but is still on the spendy end of the scale with most of them

Another thing worth mentioning, is big cams on a single throttle setup will run like a bag of shit at low rpm, big plenum making it worse again. But of course with vtec not an issue.

Was thinking about this the other day. maybe since the plenum is so small, the pipe attached to the the plenum/throttle body acts as an extension to the runner. Or yeh as @Spencer says, since there are so many brand name bolt on parts, most honda guys probably dont go down the build it yourself and test all things path. Then again how many people that put itb's on there engines, actually go further than wacking them on with some shiny trumpets and call it a day

not really, other than few different things forever ago. have got a few ideas to try, just need to figure the most cost effective and least time consuming way to go about it.

Yep, so basically simulating open throttles with a cold air feed. If i ever finish playing with the intake setup, i will go back to a setup like i ran years ago. Basically sections off the intake side of engine bay. pics of said setup in below link https://oldschool.co.nz/index.php?/topic/21725-kprs-kp60/&do=findComment&comment=1624368

@RUNAMUCK I posted some of the dyno graphs from the airbox testing a page back. but can post them all here if you like. @Truenotch Thats same graph as a page back. Yeah about 5kw there. but a dip the other way either side of it. so just trading power from one place to another. Hard to get a gain in one place without loosing it somewhere else.

Airbox testing :

Made even bigger taper runners. the 2 on the left are new ones, 70mm - 52mm . then the red tape one is the 62mm-51mm that worked best so far. then the 51mm straight. Will be a little while before can test them. but the plan is to test them as is. then jam the small one down the middle. see if its possible to make top end power with the 2nd pipe in the middle.

Long time no update. Haven't really done anything to it but managed to do a little run up the river and use it as a boat. only casualty was one of the steering box bolts. was one of the factory m10 captive nut holes in the chassis. possibly was a little janky to start with. it stripped out and bolt went goodbye. so steering box was only holding on by 2 blots. was even more like driving an old shcool bus than usual . Have drilled the sucker out and tapped a m14 in there so should be good to go again. the crack at the start of the vid ^ is possibly when the bolt shot out..

Not really, length works at both ends. so does diameter. Trying to combine the 2. on my first lot of tests best length for bottom end was 205mm. best for top end was 165mm. (or dropping way back to 65mm) but gains not worth the effort of a variable setup But combine the 205mm runner with with smaller diameter gives even more bottom end. then if can switch to the 165mm at top end with big diameter will have the gains from the airflow and correct length. Looks more worth chasing.. Would be a 2 stage variable length and diameter runner Would need to retest the lengths for the small runner to confirm. then see if its possible to get the power from the outer runner without the inner screwing the top end.

just 4. mounted in the throttles not far back from stock location

black all fixed , red bit slides up for low rpm position or maybe like a slide throttle setup that sits at the bottom and blocks the outside runner at low rpm . so the runner would be fixed setup and slidy bits would do the work of selecting high/ low rpm inside only both Edit: / TVIS

Yup. basically if i can get a setup that looks the same as that to match the top end of what i have now. then at low rpm have the outer bellmouth slide up against the bottom of the inner bellmouth. which will only allow flow through the smaller middle runner, increasing low end power

So, black pipe is 37mmm id. orange 51mm. below chart is with the pipe slid in and out like pic one and pic 2 . red being out. blue being in. the pipe wasn't slid out as much as in pic one. but it didn't make a lot of difference how far out it was. What i was trying to do here, is to see if a 2 stage, small then big diameter variable setup is worth attempting. Obviously my pipe sizes are off and the outer would need to be a lot bigger. Since loosing 15kw over normal setup up to, and down low is acting like a smaller diameter pipe still. green line added is the big 51-62 pipes as per bottom pic getting rid of the outer 51mm run. leaving the 37mm in the position of pic 2 vs the big 51-62. Would likely be very hard to combine the 2 whilst having a working mechanical 2 stage without screwing up the flow on the high rpm side. but could be worth chasing with some different sized fixed setups to see if its possible. I would set it up opposite to what i've done here. so the inner smaller runner was fixed. the outer would slide back towards the engine creating a higher flowing shorter path. Doesn't look much in the above chart, so some numbers on this one. pretty decent gain at those low rpm's

Sweet keen to give them a jam. I also tried a runner inside a runner the other day, but my sizes were off. so didn't give the results i hoped. will get a pic tomorrow of what i was attempting

Yep, seems the moral of the story is get cold air in there in some how, air box or no airbox. Maybe something in the airbox itself, but probably very little. We at least know needs to be big as possible to pose no restriction my junk will easy make an extra 5kw on a cold day vs a warm day. with the dyno correction turned off

In the tests everything would be close to the same ambient temps. bonnet open. and dyno fan blowing fresh air in. I dont have a radiator in front of the inlet. so temps aren't an issue with the open throttles soon as car is moving on road. but as i said in previous post the air temps aren't what im chasing in these tests

Thought the inlet size would be brought up. Way i see it, once the inlet pipe is that big, its just a way to direct cold air rather than some kind of intake tuning. We already know cold air makes more power so isn't really relevant. There wasn't much difference in the 3" hole vs the 4" hole. red 3" hole blue 4" hole small difference in favor of 4" hole. but could almost go down to slightly different temps rather than a gain to 4" hole. But even giving the couple of kw gain to the 4" hole. would be diminishing returns going even bigger Could probably move that bump at 7500 up the rev range a bit. but would likely drag the dips up with it as well. So to me looks like would end up with the same power curve as the open throttles. below is the same chart but the green hilux inlet run removed. so can see the difference more clearly. can see how it just trades power

I just finished testing that abortion that i built. Its roughly 9-10L Best i could get it to work was with a 4" hole and no intake pipe. although with the pipes there wasn't much difference. It changed the power curve a bit. vs the open throttles. just traded power here and there rather than one beating the other over all. So in my case at least, the airbox can match the open throttles but no better. Kinda limited testing. but conclusion I've come to so far, Is the airbox needs to be big as possible along with feed pipe. and is basically used to direct cold air, which is where the gains are , rather than the box doing anything fancy itself red - airbox with 4" hole blue - open throttles both above identical trumpets green is the plenum off the hilux. which i though did pretty good. considering how the last one performed na

Nice. Do you think there are any other benefits from the airbox other than the drop in iat's?

Sorry when i said mid section i was talking about the runners rather than power curve. What effect does your airbox have vs open throttles?

Yeh, I meant the power / torque was identical throughout the whole rev range. exhaust is 3"

How so if the power is the same?

Also, I built this abortion today

At wide open throttle, the power curve was identical. going from 47mm Toyota throttles to the bmw 52mm throttles. Only the mid section changed, so kinda make sense. working from the head out. the adapter and throttles were changed. the 110mm section after the throttles was machined to shallower taper to compensate for the 3mm bigger throttle inlet opening, the top 75mm trumpet and bellmouth were unchanged