# my 16v motorcycle itb project...



## mk2dubbin (Mar 16, 2002)

ive been keeping a thread on our local board, and thought i would start one on here as well to get feedback etc from a larger community. i will piece this thread together with the posts from the local site.
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ok, i am spilling the beans on the project since half the people know now anyway (i cant keep my mouth shut when people ask what ive been up to lately...) 
background: 
99-03 honda cbr1100XX blackbird individual throttle bodies 
42mm tapered ports 
stock spacing = 85-88mm (same as the vw 16v - mighty convenient ) 
the plan is to use oem digi1 engine management to run this setup (chipped of course with stage5 sns for a cammed NA 16v). i will update now and then with my plan of attack for how to accomplish this, but for now just play along - i have it all worked out in my head and seems 100% feasible... 
first order of business was to take the injectors, fuel rail, vacuum tubing, sensors etc off to see what i was working with. 
next comes the design/building of a throttle switch system which will allow me to run stock throttle switches upon movement of the butterflies. i removed the honda tps sensor and worked out a plan to make it work. after a few revisions from trial and error, i settled on a fairly simple system. i am sure there are other simple and pretty means of accomplishing the same task, but this is what i came up with and will stick with since i came up with it myself. its just one of those things that makes DIY so fun... 
i dont have any pics uploaded to my server yet, but maybe tonight i will get to it. for now youll just have to check out the assembly isometric i drew up for the throttle switch system. its not 100% to scale, but gives you the gist of how i am going about it... the white mounting plate will not look like that due to needing a larger plate to mount the switches on, its just how the stock tps plate looked... 
post up if youd like more explanation on how it works


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

heres some pics of the itb's so you can follow along. 
this is the intake side, which will attach to the velocity stacks, airbox ,etc. 








this is the head side, and will be coupled to half a lower 16v intake manifold via rubber couplers. 








tps is in the right side of the unit. 








fuel rail, injectors, vacuum lines etc. removed.


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

here are some progress pics of the throttle mechanism. i have the switches located as of this afternoon. i also changed out the shaft from aluminum to stainless steel and fabbed up a new inner "key." this removed the slop it had before due to me making the "key" slightly undersized. the "key" is the orange piece in the isometric above, and transfers the butterfly movement thru the plate to contact the switches. 
everything is tight and smooth now. next i will mount up the sensor plug, then trim the mounting plate to get rid of all the excess aluminum i wont be needing. having the plate oversized allowed me to mount the switches wherever i felt they worked best and was only temporary... 
heres the pics: 
keep in mind the switches arent fastened down yet, so they may look loose. this pic is in the throttle closed position. 








this pic is in the throttle wide-open position.


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

well its been a week since i updated now, so here goes. i havent gotten a whole lot accomplished since ive been busy moving, but such is life. 
i ordered the airbox (plenum) from twm and it arrived on monday. its made to fit their throttles and has a slot in it to allow clearance for their linkage. i dont need this and its in my way, so i basically need to cut it out and then fiberglas it shut to create the surface i need for mine. the good news is that there is enough room to run the oem velocity stacks in it as planned. 
i drilled out the injector ports in the throttles and tapped them for 1/4npt hose barbs. i also enlarged the injector holes in the throttle fuel rail and did likewise. when i remount the throttle fuel rail, it will become a vacuum log to generate vacuum for the brakes and mfa. the double barb system will be connected via vacuum tubing. 
i ditched the fpr off the end of the rail, drilled, tapped, and will put a plug in it. the other end i removed the fuel inlet fitting, drilled and tapped that one as well. this end will get the large hose barb for connection to the brake booster system. 
i also finished the template to correctly drill the airbox for the velocity stacks etc.


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

finding our way back from the rabbit trail... last night i started porting the lower intake manifold piece that will be used to couple the throttles to the head. i bought a $4 pack of hardened steel 1/4 shank rasp bits at horrible freight and went to town. to be honest, they actually worked fairly well for being cheap tools. i was planning on buying some good bits but figured i could use up the whole set twice and still not come out to the cost of a good single bit. 
im not doing a whole lot of porting or anything to the manifold. the primary goal is to create a "funnel" transition where the air hits the manifold. once the air comes out the back of the throttles it will expand into the diameter of the coupler and the air will run flat into the face of the cut manifold. hopefully the funnel or trumpet curve will help smooth this thransition out and keep the air moving the way it should. i am also smoothing the outside of the casting to get a clean surface for the rubber couplers to get a good seal. 
other than that i may gasket match the manifold, but that wont gain a whole lot. in general, vw castings are pretty close to the gaskets. besides that, the air has to go thru the phenolic spacer and another gasket before the head so it wont make much of a difference. i need to pick up some flapper wheels tonight and smooth out the porting from last night and it should be in pretty good shape. i will post up some pics when i get a chance.


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

the manifold is finished now as far as the porting goes, so here are some pics:


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

ok, so this week i got some other little things accomplished that im not going to bother going into detail on. then yesterday i put everything together to test fitment and what not, so i snapped some pics for the viewers in cepa-land.


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## CdnDub (Dec 3, 2002)

*Re: my 16v motorcycle itb project... (mk2dubbin)*

I'm curious why you dont think you'd need a custom chip burned for digi to work properly with this setup.
an SNS stage5 may be for a cammed 16V, but it will still be for a car with a single throttle body and a moderate level of map signal at part throttle.
with ITB's your transition from closed or 0-5% throttle and 5%-WOT is not as fine grained as you may expect
even standalone has trouble tuning with ITB's, throttle enrichment is difficult <especially without a Throttle position sensor> and map based accel enrichment wont work at all because there is nearly no vacuumn once you pass the 10% throttle mark.
I'm just asking the questions i'd love to understand what your thoughts are. It would be cool if a factory ECU was capable.


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## mk2dubbin (Mar 16, 2002)

*Re: my 16v motorcycle itb project... (CdnDub)*


_Quote, originally posted by *CdnDub* »_I'm just asking the questions i'd love to understand what your thoughts are. It would be cool if a factory ECU was capable.

all very good points. i am well aware that it is certainly not an optimal setup, but for the little bit of time that i drive it, and it not being a fast car - i think the injection can keep up. i have thought about working with sns on a custom chip, but i am not to the point in the process to where i need to contact them yet. 
i am worried about leanout when coming off-idle, but i will probably run it a bit rich to help with leanout thru the whole curve if i get on it too fast. other options are a bigger fpr, and i also have 1.8t injectors, however i dont think the g60 injectors will have a problem flowing the fuel. it all just comes back to the computer controlling it adequately. i can also trigger the WOT switch sooner than normal by adjusting its location slightly.
i welcome any and all criticism, ideas, and concerns. i know this is untreaded territory for the most part, and i am no genius. if i find i cant make it work, i will take it back to its current state and sit on the throttles until i can afford SEM - probably MS. i wish i had gone that route last year rather than digi1, but hindsight is always 20/20


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## H8SV8S (Jan 22, 2004)

You're doing a great job. I like your work with the throttle switches http://****************.com/smile/emthup.gif


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## mk2dubbin (Mar 16, 2002)

*Re: (H8SV8S)*

thanks, its not the prettiest piece but it should work quite well for what i need it to http://****************.com/smile/emthup.gif


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## [email protected] (Apr 2, 1999)

*Re: (mk2dubbin)*

Awesome work sir. I will be curious to see how this works out for you. http://****************.com/smile/emthup.gif


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

same itb's i want to use for my 2L 16VT http://****************.com/smile/emthup.gif do you have the velocity stacks or anything before the itb's? sadly mine were delivered without them so i have do mill myself some type of adapter


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*


_Quote, originally posted by *19E-299* »_same itb's i want to use for my 2L 16VT http://****************.com/smile/emthup.gif do you have the velocity stacks or anything before the itb's? sadly mine were delivered without them so i have do mill myself some type of adapter









mine came without as well. they come in pairs, and are anout $12-13US each. so for another $25 i had velocity stacks. since youre going to be running boost, it would probably be better to have the stacks incorporated into your manifold design.
i have the port spacing and mounting hole pattern drawn in autocad, but havent finished it yet. maybe i will get some time to work on it this weekend a bit. i have been considering a pair of flanges in place of the rubber couplers for several reasons, but i dont have the money to get them made and welded right now. project on hold till i get some more $$ freed up.


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

i have exactly the same problem + i must get rid of my actual car because of limited space in our street








i just wanted to take a look how honda managed it to get the airfilter to the itb's







so if you have a picture showing that, feel free to post it! http://****************.com/smile/emthup.gif


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*


_Quote, originally posted by *19E-299* »_so if you have a picture showing that, feel free to post it! http://****************.com/smile/emthup.gif


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## 19E-299 (Apr 11, 2006)

ah, ok. so i guess i have to buy number 7 two times and put some fiberglass plenum on the velocity stacks?!


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

you should actually buy both a #5 and a #7 as well. they are different pieces. cylinders 2/3 are higher than cylinders 1/4. as far as the pressurizing a fiberglass plenum - is that feasible without blowing it apart?
i am planning to run a fiberglass intake plenum, but as it comes apart - its not for pressurization. if youre going to run standalone with this setup prior to boost, i wouldnt even bother with the plenum. just get some sock filters for over the stacks and be done with it. i am trying to use digi1, so i have to run a plenum in order to mount copot in the intake system...


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

aahhh, f**k. i haven't seen that there is another number








the fiberglass plenum shouldn't have problems with ~15psi. thats were i want it to get to. should be in the near of 300hp and i think thats just perfect. 
are the vstacks made of flexible rubber or hard plastic? 
i will use MS1 with cop's from the 1.8T, if i find a ignition driver which fits







(edit2) found the driver








sock filters are some kind of unallowed here in germany. every change at the car has to be checked and sock filters aren't gladly seen over here








(edit)
do you have a picture of how the itb's were mounted at the motorbike cylinderhead?

_Modified by 19E-299 at 10:12 PM 4-13-2006_


_Modified by 19E-299 at 12:31 AM 4-14-2006_


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*


_Quote, originally posted by *19E-299* »_are the vstacks made of flexible rubber or hard plastic? 
i will use MS1 with cop's from the 1.8T, if i find a ignition driver which fits







(edit2) found the driver








sock filters are some kind of unallowed here in germany. every change at the car has to be checked and sock filters aren't gladly seen over here








(edit)
do you have a picture of how the itb's were mounted at the motorbike cylinderhead?

the velocity stacks are plastic. the itbs are fitted to the oem head via short rubber couplers. as seen in this pic:


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## 19E-299 (Apr 11, 2006)

so i can buy #5 and #7 and fabricate a fiberglass plenum on it?! should work until its hard plastic.


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

i should think so.


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## 19E-299 (Apr 11, 2006)

thanks man, i will contact my local honda dealer tomorrow to get some prices


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## 19E-299 (Apr 11, 2006)

*Re: (19E-299)*

holy ****. those horns are pretty huge








i think they are to big for me.


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

huge? they are like 2" long... anything less and you may as well not even bother because you wont get any gain out of them. however, with your engine being FI, it probably wont matter anyway.


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## 19E-299 (Apr 11, 2006)

i don't think they are just 2" long








http://www.directupload.net/sh...C.jpg


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

wow, those ARE long! mine are 2-3/8" for the long ones, the short ones are an even 2" long.







i will have to get you some pics of mine. 
i assume the port spacing is the same, so i could always get you a set of ours if youre interested. i think the spacing is roughly 86mm on center.


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

pics are definitely welcome!! http://****************.com/smile/emthup.gif


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

heres pics of mine:


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## E60 (Apr 29, 2004)

*Re: (mk2dubbin)*

There is no way you are going to want to run this thing on digi-1. Throttles take serious tuning and adjustment and your not going to want to pull a chip and send it away for every adjustment that is going to be completely necessary with a set-up like this. 
Plus, vacuum might be a problem. With the pulses of your cams (that is, if your going to run some, my guess is that with an ITB project underway there are going to be some cams under that valve cover) and your throttles a significant map signal may be hard to come by.
Edit: Nice throttles though! looking good, get your megasquirt on.


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

looking really good man, from what year are those? or from which model?
how exactly do they fit into the throttle housing without the airbox? mine have ~1mm free space all around the Vstacks


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

the throttles are 99-03 cbr1100xx blackbird. the stacks do have a significant gap between the base and the face of the throttles. i was planning on making nylon spacers to make-up the distance so i can bolt them down securely. 
as far as the digi1 goes, we shall see. some say it will handle it without much effort, but most are of the opinion it cant be done correctly. i would like to throw a mild turbo setup on the car eventually, utilizing the throttles of course, and was planning on keeping the digi1 for that as well. maybe i will run as-is for now and then put the throttles on at the same time as the turbo. that would take care of some map issues and allow for better tuning i should think...
as far as cams go, i am running a set of autotech cams with no plans of going larger in the future really. i get 16-17" vacuum at idle with them and dont currently have a problem running the digi1 NA.


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

maybe thats the difference, mine a from a 2002 cbr900 (SC50). maybe thats why my horns are so big


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

yea could be, i thought you were running the same throttles as mine...


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## E60 (Apr 29, 2004)

*Re: (mk2dubbin)*


_Quote, originally posted by *mk2dubbin* »_
as far as cams go, i am running a set of autotech cams with no plans of going larger in the future really. i get 16-17" vacuum at idle with them and dont currently have a problem running the digi1 NA.

Yes, but a mild set of bump sticks are nothing in comparison to the low vacuum condition of ITB's. That's not the real issue you should be concerned about though, its the tuning. Talk to dude...wait for chip..put it in...wideband or dyno...pull the chip...put in different chip...wideband or dyno...pull.ect.ect. Just spend the 200 on a MS kit....and especially since your 16v is already set up for EFI.
There is nothing wrong with a mean digi-1 setup (cams, porting, all that good stuff) but for throttles, I bet its going to kill your buzz.














good luck though! looking forward to see the progress..


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## 19E-299 (Apr 11, 2006)

*Re: (mk2dubbin)*

the throttles look absolutely identic. maybe they changed only the v-stacks


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## mk2dubbin (Mar 16, 2002)

*Re: (19E-299)*

i talked to jwatts and here is what he had to say:
_WOT would be the easiest part of tuning an ITB setup. It's easy enough to find the atmospheric pressure lines in the maps and tune the timing and fueling accordingly.
If you have a vacuum accumulator tapped into all 4 runners, there is a chance of getting a signal to the MAP sensor and having part throttle work out o.k., but that is an unkown to me since I haven't gotten my grubby hands on an ITB setup.
If a MAP sensor won't work for Digi-1, and other MAP based setup will work the same. In that case, an Alpha-N setup would be the best bet from one of the other stand-alone systems (Throttle Position vs. RPM)._


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## oopseyesharted (Mar 2, 2005)

*Re: (mk2dubbin)*

wholly ****!!!!
that looks great!!!!


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## mk2dubbin (Mar 16, 2002)

*Re: (oopseyesharted)*

back from the near-dead, this project is back in the works since i have changed over to MS in the recent months. just a few update pics:
here you can see how i whittled away the factory plastic webbing to allow me a place to clamp the filters onto:
















this is how i wound the spring onto the stacks:








both mounted on half of the throttles:








the throttles put back together, the stacks bolted into the throttles, and the replacement tps sensor installed:








notice the white nylon spacers used between the throttles and the stacks. originally the bike airbox would have bolted between them. i needed a spacer since i obvously will not be running an airbox around them.








ive also ordered the parts i should need to fabricate a custom throttle cable, so we shall see how that goes when it all arrives. almost time for a mockup on my spare engine to check interferences.
i will try to remember to update this thread in case people care on here. i generally update on our local site pretty often...


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## AaronAnderson (May 26, 2006)

SWEET


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## mk2dubbin (Mar 16, 2002)

*Re: (AaronAnderson)*


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## VWralley (Mar 30, 2002)

*Re: (mk2dubbin)*

glad to see your stickin with it! if you have any issues with the tuning of these let me know. make sure to sink them before tryin to tune at all! i had a hell of a time getting it nice an smooth until i did this


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## mk2dubbin (Mar 16, 2002)

*Re: (VWralley)*


_Quote, originally posted by *VWralley* »_make sure to sink them before tryin to tune at all! i had a hell of a time getting it nice an smooth until i did this

it idles like a rock, actually better than in the stock 16v form... kinda weird. mine should be synched just fine since the linkage is in the middle and didnt have to be spaced like the common gsxr bodies.








just sitting in the driveway with some light revs it went lean immediately. i am going to need some heavy AE at first just to make it driveable during early tuning. 
they are quiet at idle and during revving in the driveway. maybe they will be loud on the highway though. my exhaust note is super loud now, and it was loud before... wasnt expecting the exhaust note to change much.


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## VWralley (Mar 30, 2002)

*Re: (mk2dubbin)*

i have my fuel map up on pats web site (or at least he has it) it is meant to run with a solid rate fuel pressure reg. if you would like to jump start your tuning, you could start with that and scale it as needed to get the car to drive. i have done this on several diff configurations (stock intake vs my itb setup) and it works quite well once you find out where it needs to be http://****************.com/smile/emthup.gif 
its acutally active in three different cars that i literally imported the map, scaled it till the car ran nice, and left it alone. the wideband readout said everything was actually really close to where it needs to be, 16ish at cruise 12ish at heavy throttle


_Modified by VWralley at 1:02 PM 12-27-2006_


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## im_a_local (Jun 4, 2004)

*Re: (VWralley)*

Looks good. http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## autocross16vrocco (Jan 17, 2003)

*Re: (mk2dubbin)*

looks good.. i didn't see it in the post anywhere but how did you attach the 1.8t fuel rail to the manifold?


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## mk2dubbin (Mar 16, 2002)

*Re: (autocross16vrocco)*


_Quote, originally posted by *autocross16vrocco* »_looks good.. i didn't see it in the post anywhere but how did you attach the 1.8t fuel rail to the manifold?

you cant see it in the pics, but i used some bent brass bar. i bent it from the fuel rail tabs down to the nearest manifold bolt. i used bolts on both ends. its not as perfect as a welded tab, but works quite well. http://****************.com/smile/emthup.gif


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