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Are my honda cbr 600 throttle bodies enough?
thepest - 20/11/09 at 09:43 AM

I'm planning on using them on a crossflow 1.6L
Has Kent 244 cam, around 140BHP would they be sufficient?

I have fueling concerns


cd.thomson - 20/11/09 at 09:51 AM

Presumably you'll be controlling the injectors anyway with an ecu and I'm sure they'll flow enough.

on a side note - I don't know anything about crossflows but an older engine with a 1.6l capacity producing 140bhp is pretty good!

My 2L DOHC XE will probably only produce 20-30 bhp more than that with carbs and a big exhaust!


Project7 - 20/11/09 at 11:07 AM

Are you planning to use the Bike Injectors? I think the CBR600 has approximately 100bhp and you are looking at 40% increase, so the standard injectors *might* be border line.

Do you know the flow rate of the standard injectors?

I *think* you will require somewhere in the region of 230cc/min plus.

[Edited on 20/11/09 by Project7]


thepest - 20/11/09 at 12:27 PM

I found on forums that the flow rate of the standard injectors are 19lb/hr and the standard is at 43 psi. According to this calculator I can get 145 bhp with 60 psi... but its all trial and error. I was hoping someone has used this before to avoid me having more error than trials


wilkingj - 20/11/09 at 12:30 PM

I seem to recall the CBR 600 had dual injectors? ie 8 of them (4 in the bodies, and 4 in the airbox area).
Having said that, there is a Rover V8 using 8 x CBR600 Tb's. Dont know what injectors they used.

Look about 1/2 way down this page.
If they can run a RV8 then a Xflow should not be a problem.

Linky

Two questions....
Are 38mm TB's big enough?
How well are they spaced, and would different ones be easier to space out.

In the good old days (1970's) we all used to go for DCOE 40 Webbers. However, 38mm TB's are not that much smaller.

I assume you are going megasquirt or similar.


will121 - 20/11/09 at 12:31 PM

what size are the throttle bodies? if like early GSXR600's at 38mm dia they will be plent big enough in size and reported to be still ok at 180bhp+ as for injectors again would think ok as later models 2005 ish CBR600RR's were around 120bhp but you could check if you know what model they are from?


thepest - 20/11/09 at 12:41 PM

They are 38 mm in dia, I have no way of checking from which bike they are from though, whenever I google Honda cbr 600 throttle bodies I get matching pics though. There were another 4 in the airbox area however I dont have them just the throttle bodies injectors and fuel rail.

I used to use DCOE 40s and I'm thinking that the throttle body setup would be alot nicer. I had no probs with the webers before, I just want to play around with megasquirt a little, I want to learn how practical efi is.


will121 - 20/11/09 at 06:36 PM

quote:
Originally posted by thepest
I found on forums that the flow rate of the standard injectors are 19lb/hr and the standard is at 43 psi. According to this calculator I can get 145 bhp with 60 psi... but its all trial and error. I was hoping someone has used this before to avoid me having more error than trials


just tried and worked it out long hand, and your sugestion seems to work out, but would think upping fuel pressure at 60psi a bit high, assume as the 600 has a 8 injector setup they are individually quite low flow rate. what are the honda injectors like? can you change them for say CBR900 ones or another one?


thepest - 22/11/09 at 12:19 PM

I have no idea... this is the first time I try out efi I'll look around for bigger injectors. but I guess a photo would help...will be up shortly..


rusty nuts - 22/11/09 at 01:01 PM

My 1600 Xflow made 127 BHP on Emeralds rolling road running on ZZR1100 T/Bs with a 35mm bore so yours at 38mm should be fine. Can't help with the injectors


thepest - 22/11/09 at 03:29 PM

Hope so... will find out soon enought & will post again. Thanks


clutch_kick - 23/11/09 at 05:53 PM

Philly, next time give me a call, I had coded an excel sheet to do all this

You're going to need 250cc injectors, which equate to approx 178bhp maximum, and that is running them at 3 Bar which is usually the stock figure. Increasing pressure a little bit is ok, but too much will give you valve opening problems.

Get the throttle bodies machined to accept automotive injectors and ditch the bike ones. It will make life A LOT simpler, specs wise and will broaden your choice of injectors.

And fit a thremostatically controlled oil cooler



[Edited on 23/11/09 by clutch_kick]


MikeRJ - 8/2/10 at 11:54 PM

quote:
Originally posted by wilkingj
In the good old days (1970's) we all used to go for DCOE 40 Webbers. However, 38mm TB's are not that much smaller.



38mm throttle bodies will flow way more than DCOE 40's and nearly as much as than 45's. Don't forget the venturi size in a 40 DCOE has a range of 24-36mm, and 28-42mm for the 45 DCOE.


thepest - 9/2/10 at 01:14 AM

Answering my own question, yes they do flow enough, peak power at wot with AFR of 12.5:1 using 75% duty cycle on the injectors.