What management are you using Shiro? I've never done tuning ITB's before and would not see myself tuning other than single tube manifolds. That your motor?
What management are you using Shiro? I've never done tuning ITB's before and would not see myself tuning other than single tube manifolds. That your motor?
Well, undeniably, single tube manifolds are some of the easiet and least confusing setup to tune, due to the lack of options.
There's plenum volume, which does little, and then there's runner length, which is not in the direct control of the tuner, but the manufacturer, which probably designed it to run with his xx cams, his xx pistons, with xx compression, with xx stuff.
Certainly, it's more comfortable to try a tried and true setup, isn't it? But with most setups already tried, isn't using ITB something slightly newer?
ITB's have varying height velocity stacks, trumpet length, injector positions, etc. Even I don't understand half of it,, to be honest.. ha ha.
ITBs are said to be more difficult, and also difficult to tune right, esp for use in daily driving. I'm trying to do something like that, and it's there, for the most part. I did a 2000rpm idle once, but once I saw how much fuel it used for warming up phase, suddenly having a race oriented tune isn't such a good idea.. lol.
Management, I'm using my Hondata S300J,
MAP indexing for idle, Secondary maps engaged on part throttle with TPS indexing, higher RPM returns back to MAP indexing.
I can't seem to get it to idle on TPS indexing/alpha-n. Having full TPS indexing is way more responsive (I tried), but I think the new Hondata 1.3.8 has issues with that, I believe it's a problem with the MAP sensor compensation, but I haven't gotten around the time to test it further. It's something I'm trying to learn after all.
With MAP, it idles just like my B16A lol, and it drives really well too. I just want to do it the full TPS indexing method just for knowledge and experience.
As to the setup
It's a B20B, 11.8 compression, Jun 3 cams
OER ITBs, setting those idle bleeds were confusing, for the first 2 minutes.. lol. easy once you get the idea down. Thankfully I could even borrow a Weber DCOE's vac meter to balance it out.
Still running on conservative timings, at least until it's strapped to a dyno.
Anyway, there's still some few mods to put in, but futher testing will determine what's needed and what's not. Currently temps hovering around 85-87, which is normal, even with a racing thermostat and the DC2 wide radiator (as you can see from the video). Could be the slightly retarded timings I used. Peak timing is only around 27ish, still on BRK-7s. It'll need 8s to go higher.
Currently I do think the ITBs are a bit too small for the B20B though.. I'm basing that thought based AFR curve versus duty, so that's a preliminary thought. It could be the exhaust. It's stupid to change both and not find out what exactly is causing the restriction though.
but then again, it's a first, so going to relax and take my time. This ITB drives like a standard car though, so its kind of strange to hear stories from other people about lag when using ITBs, and etc, when this car has none. In fact it's a bit hard to drive when starting from a stop, because the car just jumps at the slightest throttle. Have to ease the clutch and move, which makes it feel a little like an automatic.
Idle is at a surprising 1,100rpm only :slug:, No IACV or FICD for idle control. It idles at 16-14.7 depending on the time of day.. lol. At nights, it sometimes idle at 16, but when the ITB runners warms up, it will idle at stoich.. But with such low idle, opening up the throttle requires a heavier foot, no thank to the vaccuum. Thankfully messing with carbs that didn't have idle control systems helped me understand how to obtain desired idle characteristics through fuel and ignition and also idle air bleed. So it idles pretty much like my B16a.
Top end power is still lacking though, but when it's still using a restricted exhaust, not much to say about that. Planning to stuff in 2.5 inches later on so hopefully will get more power up top. Currently the torque peaks (according to Innovate AuxBox G sensor) at around 6500, and not gradually dropping off, but more like failling like a brick, and there's a huge difference in fuelling at the 8K range to get it to run close to 13 AFR. Looks like restriction though, but with closest exhaust size being 3.5 inches from a subie in stock, guess have to wait to get something a little more decent. The mapping is up to 9K, but it's rev limited to something decent like 7800, because't it's not making power past that 6.5K mark. Unless that restriction is taken care off, the B20 will not see 9K rpm, Anyway peak rpm I will base on peak torque. If 6500 is the best it will manage, then it will be rev limited to 7.8K. No sense revving it up till it misses the peak torque at each shift.
As for the question by prasath_5338,
Gains? With the current setup, I can't say I gained anything. The ITBs offer only one difference from the single plenum setup before. FASTER throttle opening, which equates to faster response, IF tuned properly.
The initial basemap was so horrible, I
gained black smoke from the exhaust from sub 11 air fuel ratios. Ha ha.
Peak power is roughly similar, but hard to test when being so close to raya, many people are 'cruising' so can't really test it to the max. So far no one driving it dares to hit 8K on the forth yet. Steering is super wild with that much torque.
Based on g sensor, should be making about 180-190hp at 8K rpm, like I said not much difference at peak rpm. but it's interesting to note that it generates that amount of power at 6K too. There's just no increase in power after that 6.5K mark because the fuel curves drops like a brick after that.
the only diffenrence is the midrange. Torque at 3-6K is absolutely scary. Have to hold steering with both hands when accelerating. Even with full lock, the car can suddenly drift to one side when shifting.
But with poor top end power, there’s still some mods to do before I can conclusively say it's completed.
I don't expect it to generate a lot of hp past 7K though, there's probably way to much parts that are more suited for a B18C than a B20 on it, and buying super expensive headers from hytech and Jenveys/TWM is not an option.
Heck! B20B blocks plus VTEC line is cheaper than an equivalent B18C block.. So that's a no arguement why this setup ended the way it did. :P
I'll record a video sometime, and overlay the hondata engine parameters on it like I posted in my hondata thread a while back, but there seems to be a distinct lack of interest on ZTH on mods that go beyond buying a part and bolting it on.. :P
. u can inquire directly with the workshop on the quad setup that fits your budget..
