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DOHCDX ...

I measured the "slack" between the Z6 TB throttle "spool" and the throttle cable bracket ... then I bent and formed the CBR throttle cable bracket so that it was the same distance from the TB "spool".

The Excess throttle cable will be routed as best as possible in the engine compartment.

Cheers

Moose
 

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D15b2 / CBR 954 Throttlebodies

Here is a pictoral outline of my "homemade" CBR 954rr throttles on a D15b2 Built specifically for SCCA Solo2 E-Prepared class rules. They have been operational for about a month and have been dyno tuned. The engine is making +100hp/liter with almost no tuning. There is still much more to be found with different runner lengths, trumpet shapes, and header/exhaust configurations. Hopefully a Bisimoto header will find its way into the engine compartment soon.....
 

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the beginnings of my ITB set up:





i'm going to cut down the y7 manifold and either weld in custom runners, or just use the stock ones as the spacing ends up being dead on about 2 or so inches away from the flange.



they are cbr 600 tb... the diameter is 38mm just behind the butterflies.. the y7 manifold has a width of 39 mm, but only a height on either side of the injector of ~32mm.... so i figure they ought to be sufficient in size.
i'm just going to use the stock injectors in the stock locations. i could make the stock injectors work in the gsxr fuel rail, but i am unsure of how that will affect injector timing, etc. i figure stock location will work just fine. UNLESS someone can show me if it will be beneficial to put them in the GSXR location.
 
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AudioMan said:
as for the injector sizing i was thinking about it for a while and here is what i came up with.

A motor is a motor right?
What seperates the 929 motor from a d16?
They both are 4 cylinder and both have close to the same power output.
So why can injector sizing be done the same way?
IF you put 130hp (y8) into the injector formula, for a 4 cylinder engine you get 213cc at 80% duty.
well, the 929 puts out about 140hp. put this in the formula and you get 230cc at 80% duty.

we all know that is not gonna run the injectors at 80% duty that is why the y8 has 240cc injectors in it, thats about 70% duty.

Now if the cbr runs its injectors at 70% duty that would be about 260cc.

This is just a theory, but they could not be less then 230cc
the one thing you're forgetting here is fuel pressure. Honda could use a much smaller injector on the bike because of the high fuel pressure that they run. I know the CBR 954RR stock fuel pressure is about 52 psi, whereas the stock d16z6 is low 30's I believe. Don't forget those same 240cc injectors (from the d16z6) are used on the B series engines. The spray pattern might be different but the flow rating is the same. Honda seems to run the injectors at a fuel pressure that puts them really close to 100% duty cycle at redline for full load. For example the b16 fuel pressure is 38psi , b18c1 is 42 and b18c5 is 45 (i'm pretty sure those are all right, not 100% on the ITR motor). The duty cycles are all pretty much the same, just different pressures. Honda must have realized a benefit to doing this because they do it across the board on the cars.

The 954RR motor has such different characterisistics who knows what flow rating they are. The high rpm's that the motor runs at they might need a really high fuel pressure because of the high pistons speeds and make them a really small pulse width (so pushing out more fuel in a smaller time). How that relationship rates to what the flow rating might be I'm not sure. So, it's all a mystery for now. At any rate I'm gonna try them out and see how they work. I'm betting if they can handle the 140hp bike motor they'll easily handle a d16z6.

s
 
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Moose said:
So now I am in the process of figuring out the vacuum and coolant routing, and what I am going to do with the Injectors. I have three choices, Highflow CBR inj from RC, Modified Prelude injectors in the stock CBR location, or Prelude injectors in the Z6 stock location.
I'm pretty sure stock honda injectors for the car will just drop into place, no mods needed. I'll have to double check but I thought someone did that. For my project I'm going to put the injectors in the stock bike location. I guess the tradeoff is idle and high rpm power. At the stock d16z6 mani location they are easy to get to idle lower but you might suffer some high rpm power. In the stock bike location I guess idle gets tricky but that location is much better for high rpm flow. This is just what I've heard and is hearsay, in my mind til I try it for myself, so take it with a grain of salt.

Moose said:
Once that is done ... the tunning becomes the issue. I think i may have resolved the low vacuum issue and how it impacts tunning and the A/F maps. A local tuner is building a custom re-curved Map sensor (he builds Turbo Maps) for low vacuum situations.
please elaborate on this? So what's it going to do? You're gonna get a custom map sensor that will put out a similar voltage at idle as the car map sensor but this re-curved sensor will put out the same voltage but with less vacuum needed for idle. Seems pretty complicated to get it right. You could really mess up the map readings you're going to get. Changing the value at idle could have a big effect on what you get at WOT. Gonna have to do some testing to make sure you didn't make it worse.

Moose said:
This hopefully will allow me to tune properly using Hondata, with out having to resort to TPS only tunning below 5k.
From the people that I have talked to that have tuned ITB's if you do the vac canister like you are and T all 4 together you won't have a big issue getting good vac readings. As far as TPS tuning with hondata it's not possible anyways. Hondata only allows tuning based on map readings. That's why a lot of people like the AEM, it allows TPS tuning.

steve
 

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SteveL

The Z6 injectors will fit in the CBR locations BUT the Z6 injectors are taller, so the fuel rail sits higher ... you have to use washers/spacers to allow you to bolt the fuel rail down

Difference in height between the CBR and Z6 injectors



Z6 injectors installed in the CBR locations



Z6 injectors in place with CBR fuel rail




Here is a close-up of the Fuel rail and mounting points




Vacuum logs ... there is a lot of conflicting info on wether or not a log is required .... I decided not to run a log ... I figured If I had problems I would just add a vacuum canister after the fact. I ended up epoxying in some barrbed nipples and then I teed the lines together ... this vacuum source will feed the Brake Booster .... the OE CBR vacuum lines will feed the MAP and FPR. I decided to use the OE CBR vacuum ports for the MAP because they have a smalled orifice ...I suspect to provide a more accurate (finer) Map reading








Re-curved MAP ...
The MUCH lower vacuum that the ITB's provide EVEN with a Vacuum log causes the MAP to read wrong (voltage range is smaller) ... It is similar to how a huge cam causes tunnning and idle issues.
When you start hacking the ECU (Hondata etc) look-up tables, the lower vacuum and reduced voltage range of the MAP re-distributes the A/F tables, causing a reduced tuning resolution in the higher RPM bands. This make tuning difficult, so I asked a local tuner to create a custom map sensor that compensates for the lower vacuum by allowing the MAP sensor to output a normal range of voltages. This MAP is similar (but opposite in correction) to a Boost (2 or 3 bar) Map sensor. I hope that made sense


Cheers

Moose
 
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I might need that special MAP sensor too, depends on what DOHCDX made from his ITB's.. Looking very, very good i must say.. keep up the write up..
 
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DOHCDX said:
you don't need to use a re-calibrated MAP. compensate for the reduced vacuum when tuning by leaning out fuel.
So I understand from a PM from you a while back.. still laying on the shelf... will be put to good use sooner or later..
 

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Discussion Starter #58
By the way, I have an extra y7 intake manifold. The plenum has been cut off where it meets the runners. If someone needs a flange for ITB's all you would have to do is cut the runners off and weld some straight tubes. $15 shipped.
 

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This one's for you, Duck.
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Man, this thread needs more love. :lol: I can't get enough of it. Once someone gets their project done the need to do a full write-up detailing what parts were used, how certain engine bits were re-routed and accounted for, etc. Oh yeah, and of course pics and VIDS.

Also, this guy on H/T sells custom made flanges with welded runners for ~$160.
link

EDIT: the guy above will need an IM gasket for your application for D-series motors.

Keep the pics coming guys! This will deff be going on my NA build. :thumbsup:
 
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