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[GEEZER-X]

Hey guys, can anyone tell me if I would gain anything from a bigger throttle body on my 04 SE bagger,, I'm dealing with a 107ci kit from revolution performance, Head quarters worked heads with 10.6 compression and their 0033g cams, 600 lift and 533 exhaust, thunder header, hypercharger intake.. the bike on the dyno made 115hp with 130 torque,, im still using the 44mm throttle body, stock I think? wondered if a bigger TB would help the cause, or maybe the dd Fat cat exhaust?  then again maybe leave well enough alone,, Any ideas on this subject,, I would appreciate any thoughts. The bike runs sweet, but you know how it is, a little more never hurts.. No problems with anything yet.. thanks.

[Unbalanced]

Geezer,

If the heads were setup correctly it should help, but that is really a better question for the Headquarters people as they are the ones that flowed the heads and did the work and can tell you if the heads can handle the volume and whether it will adversly or positively affect the velocity of the air inside the heads.  They should also be able to tell you what size you should look for to get the most out of the heads.  If they say yes your most likely going to want to get the bike back on the dyno for some tweaking after installing the new throttlebody / possibly injectors as well.  I would suggest looking at the 49 or 51 mm Horsepower Inc if you go this route.   

The caveat you can run into is if the heads have no velocity and you push even more air down into them you lose the bottom end snap and then when the heads catch up you take off like a bat out of hell.   In some cases when you have this problem you can use a smaller throttlebody to mask the problem that the heads actually don't have the velocity to go with the volume. 

Whether you call Headquarters or not the only real way your going to find this out at this point is to try the larger throttlebody and see the results.   Unless your willing to remove the heads and have them tested on the flow bench with the throttlebody of choice and the throttlebody you currently have to compare the flows at 10 and 28 inches. 

Btw the 04 CVO came with a 43mm throttlebody with 25 degree injectors setup as 4.35 gm/sec

[GEEZER-X]

Unbalanced: Thanks for getting back with me, and the information. I'm sure I can call Headquarters and as you said ask them, seeings how they set up the whole build. I have heard that to big of TB will take away the low end, which I do not want to do. As I said I might not even mess with it, put a Thundermax autotune on it and call it good. I do appreciate the time you took to email me. Also thanks for the correction of the size of TB being a 43mm. Man the more I get involved in the engine stuff, the deeper it gets.. At least on this web site a guy can find out new stuff. Thanks to all. Geezer

[Unbalanced]

You're very welcome.   I hope to have the FTP Server running again soon, it is a glitch with the new modem that they sent me, so I am awaiting a new one from them that they say will allow me to port forward to allow the ftp server to be backup and running.   I guess we will see.

-harry

[GMR-PERFORMANCE]

It is very easy to tell if you need a larger t/b. While under heavy load what is the map doing??  You would need a data log file to look at. But if you are using a stock t/b on the 107 it  is more than likely not large enough. You may see that your injector duty cycle is getting very high. This cause's a problem as the injector is spraying too long as you end up spraying on a valve that is closing or is closed by the time the cycle is done.  The best way for a injector to work is under 60% duty 80% being the max. You want high pressure and short "on" time.  So I would check fuel PSI as the stock injector will handle 160 hp. ( my own bike) with increased fuel pressure. You can modify the fuel reg.

 The tq dip you have is the t- header did they work with the baffle fins?? the a/c unit you have is not the best either( testing has shown that ) The Hp unit is a great unit a 51 would work well if you are looking to get the largest numbers a 55 would get that job done. If it where me I would opt for the SE unit. The stock injectors may work but I would need more data before I could tell you if they are maxing out. If you run them too hard they will burn out as they are "on" too long and do not have time to cool, they will overheat and stop working.  You have a nice build I would work on tweaking what you have first before throwing more parts at it.  The fuel curve could use work,

The flow numbers will give you a start from there looking at the map while on the dyno or with data log info will tell you even more. It is all in the testing, I have no idea what the head you have flows so as i said before adding more parts work the items you have until there is no more, then if you still want more power go from there.  Who knows you may be very happy with more tuning , and save the cash to take a trip. More fun that way HA HA .

[GEEZER-X]

Wanted to take a moment and thank you for the information.. I have a question or two so I can  understand a little better.. What is the ac unit? air cleaner? also what is the hp unit being a 51 would work? I did see where the fuel curve was not great on the low end of things. I am heading to NM and hope to have a better tuner remap it, or the TM auto tune. Any ideas there? the tuner is pretty sharp. I read and hear both ways on the Dyno tunes, or the auto tunes. I'm a little afraid of the auto tune because there is no one around here with the experience to tune it if something should go wrong or need some tweeking. The things you mentioned about the TB and injectors is a little over my head. I will copy what you had to say and show it to my builder and see what his thought are. Not sure where to get the information one needs to make those decisions,, maybe seat of the pants? As I said the build runs well compared to my old 95 ci. As I said I will see what my builder thinks maybe he knows about the some of the information you mentioned.. Thanks again for you advice and I will check it out.. By the way the Thunder header does have a device in the end of it for some sort of tuning help of the pipe, the NM tuner put it in there, it bolts in kind of like a litte metal plate, for back pressure I would guess. Well any other information you think I could use please let me know. Sorry I didn't know some of what you were mentioning, I'm trying to learn kind of after the fact, but appreciate it.. Geez

[GMR-PERFORMANCE]

We all learn every day, heck I am learing about toilets right now. HA HA I have to replace one at home? I am working on it, always seems I have the wrong fitting for something. I really hate working on plumbing.