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fuel controller question

10K views 26 replies 11 participants last post by  tylerltr450 
#1 ·
hey guys ive been doing alot of researching to learn everything about the ltr as i did the trx 450. but ive come across one thing in particular that really stumps me.

okay i have a power commander III, which as far as i understand is just for the fuel controller, but then i also have a cherry bomb, which i understand changes the stock fuel map and the timing curve. correct?

but now there a 3 maps floating around in my wire harness, stock, cherry bomb, and custom pcIII map. how in the world does my quad know how much fuel to give itself? and what would happen if i unplug the cherry bomb? im assuming it would run lean or anything.

on the PCV, which i will get one day, not soon, i though you couldnt run the cherry bomb. whats the difference? the PCV and PCIII are both only fuel controllers as far as i understand.
 
#2 ·
on the PCV, which i will get one day, not soon, i though you couldnt run the cherry bomb. whats the difference? the PCV and PCIII are both only fuel controllers as far as i understand.[/QUOTE]


I know this from my quad you can not run a pc5 and a cherrybomb that they will cancel each other out. SO when you get your pc5 you will have to unhook the cherrybomb. Did you buy the autotune system to?
 
#3 ·
thought so^^ but what makes the pc3 different? anyone else?
 
#4 · (Edited)
drag ltr no offense but this is not correct,the pcv comes with a rev extend plug which is the same thing as the cherry bomb,you need it pluged in for the programer to work properly,and 2005450r the difference between the two is the pcv will accept the auto tune feature which in my opinion is one of the best investments you can make for this bike.
 
#6 ·
drag ltr no offense but this is not correct,the pcv comes with a rev extend plug which is the same thing as the cherry bomb,you need it pluged in for the programer to work properly,and 2005450r the difference between the two is the pcv will accept the auto tune feature which in my opinion is one of the best investments you can make for this bike.[/



my quad doesn't have that rev extend plug I never heard of it they make a plug in module that you can use to set your rev limiter maybe that's what your thinking of and i have auto tune so maybe it's different? I know this for sure the pc5 and cherry bomb will not work together.
 
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#5 ·
thanks^^ so theres really no difference in the except the 5 is smaller and has auto tune, which i really want.

but if the 5 has the rev extended feature why does it need the cherry bomb
 
#7 ·
Both the PCIII and PCV come with that "rev extender plug" thingy, they do the same thing as the Cherry Bomb. They unlock the "race map", which as I understand it richens the bike up a bit and ups the rev limit to 11,200. Since they do the same thing, the Cherry Bomb was left on my bike when the PCIII was installed. Not sure if I still have the Dynojet version of the Cherry Bomb or not.
 
#8 ·
so then whats the purpose of keeping the cherry bomb then? in my eyes thats unneeded wires and weight if theres something better in its place already
 
#12 ·
Lol, weight!

It is my understanding that the PC III and V can override and adjust the fuel maps with or without the Cherry Bomb, but in order to increase the rev limit, you need to have either the Dynojet rev extension plug, or the Cherry Bomb itself.
100% accurate. Im carbed and still have the cherry bomb for the higher rev.
 
#9 ·
Alright so this plug is just made to extend the rev limiter and richen it? Because that doesnt make sense honesty to me because you'd be like defeating the purpose of the pcv or pc3? We need someone who knows exactly how this setup works.
 
#10 ·
It is my understanding that the PC III and V can override and adjust the fuel maps with or without the Cherry Bomb, but in order to increase the rev limit, you need to have either the Dynojet rev extension plug, or the Cherry Bomb itself.
 
#17 ·
This is exactly how I understand it as well, without either the Cherry Bomb or the Dynojet rev extender plug the PCIII/PCV can adjust the fuel, but not the rev limit so your A/F would be correct but you'd still be working with the stock rev limit.
 
#13 ·
So you guys run a pc5 with the cherry bomb? Because my engine builder/ tuner said he tried it they just canceled each other out.
 
#14 ·
Yes weight, that's like 3 ounces keeps my frontend planted lol but back to serious. So basically the cherry bomb is just a plug that puts the rev limit at 11200 then my pc3 over rides the bombs map into an adjustable map so if it unplug the bomb my rev limit will fall but it will run the same at low rpms
 
#15 ·
im gonna see what my engine builder says about it, it doesnt really bother me having both, i just want to have the best setup possible and i want multiple opinions on it because just asking one or two guys all the time doesnt really show what other people have research and discovered
 
#16 ·
have you done a search on here about the pcv?there was a very good write up a while back by leasureryan,he was very knowledgeable with this programer but i dont think he comes online anymore,I have ran it for allmost two years but have never understood it the way i would like,also not all engine builders are as familier with them as they should be so be carefull with that, I do know that the cherry bomb and the rev.extend plug serve the same purpose and plug into the same place,I used the plug that came with the pcv and sold the cherry bomb,my bike ran like crap without it pluged in and also they do not cancel each other out like stated earlier,good luck
 
#26 ·
PCV problems




I know this is an old bread but nobody knows enough about these😡..also forgive because this is my first posting. First off I bought mine used years ago with PCV and ended up putting Stage 1 in/ex. Idiot put the shims in backwards. ANYWAY?.. I never really got to looking at everything until the other day and realized that t didn't have the Dyno rev x thing nor a cherry bomb connected but it did come with a brand new cherry bomb so I threw it in to see what would happen and after maybe 2 min of idling my temp light came on solid. I checked etc sensor blah blah blah.. idk what to do just take it back off? I live in ND and there isn't a tuning center anywhere near. I'd say don't use cherry bomb with pcv.. ps. Air box lid removed with yoshi full system
 
#18 ·
whats the stock rev limit? with the cherry bomb on mine its very hard to get it up to the rev limiter. my motor hasnt been touch yet which i assume has some to do with it. also how does the timing curve go? isnt that along with the cherry bomb? so they cherry bomb uplugged would give me a stock curve and a stock rev limit, or are all settings the same timing curve.
 
#19 ·
The stock rev limiter is 10,500. Yes the cherry bomb does change the timing curve. If you unplugged the cherry bomb that would probably be a bad idea considering your motor. And thats weird that it is hard to hit your rev limiter because when i had the cherrybomb i always hit it and i know how you ride :/
 
#20 ·
haha i know dude i seriously didnt actually hit the rev limiter yet fully i dont think

compared to the honda though i can bogged the ltr down alot more and come out of a turn in second and its torquey and snappy enough to haul. i have alot more practicing to do but this i like the low end power out of it so i dont have much need for the high end
 
#21 ·
its not hurting me to be running the pc3 right now is it? my look at it was you could always have a perfect tune with a fuel controller no matter what mods you have, and since i already have it it would hurt me i didnt think.

i wouldnt waste my money on one right now because of only being piped, intake and no lid. but i cant just stop there and call it good. lol i like horsepower even though right now i have just alittle to much. i havent actually thought to my self on the track that i couldnt hit a jump because i didnt have the power
 
#22 ·
I finished my build last summer and went to Saint A's. While draggin Choke I couldnt figure out why my Big Bored Ltr was no faster then my buddies (nearly stock) Ltr with an exhaust and CB. Not to mention I was running HOT and white powder started to form on the exhaust. I could tell a difference in torque between the two but We were neck in neck when draggin. I couldnt figure it out till one day i looked at the electrical connector cap in the PCV kit and it hit me. . . the cherry bomb will override the stock fuel curve as well as the pcv, It took me a min to prove to myself that this was the case but this is the little test i did; With the CB plugged in I started the quad with the laptop connected to the module. Gave'r some gas and Kept an eye on the RPMs per throttle position and also keep an eye on the A/F ratio (Taking note on what they read vs the inputs on the table). They didnt match up so i simply unplugged the CB and started the same process without. I noticed a difference in curtain throttle positions and rpms when disconnected. The table wasnt matching the a/f ratio and RPMs in all the throttle positions while running with the CB. Only then did I realise what the only extra part left in the kit was for that i hadnt used (palm to forehead). Feeling dumb I unplugging the CB and put the cap in its place and the tables matched the little running stats on the right of the map. NOW, It sounded like some one said earlier on this thread that the cap is also a rev extention but I dont think that the cap is a Rev extender, only because when installed i was only able to redline at stock limit. Hope this can clear up some debate. I also have a few questions, (Is there a Rev extender that has no additional affect on the stock fuel curve other then the extention?) ALSO... I went hunting for a good starting point on a fuel map for my new build and i ran across some fuel maps with all negative numbers and some with all positive numbers. Its my understanding that The numbers on the map represent the A/R ratio on the table throughout the throttle positions. But if thats the case then HOW IN THE HELL, is it that someone can run all positive A/F with nearly the same setup as someone else with all Negative numbers. Im confused about this and hope someone can walk me through it. THANKS
 
#24 ·
thanks alot for clearing that up!! so basically the cap is just to like ground that out almost then its just all in the stock box and the pcv with the pcv being the override on the fuel map
 
#23 ·
Inside of dynojets rev extend plug is a resistor, that is what is "unlocking" suzukis race map. Inside of a yoshi crmb is the same thing. Me and my buddy are both running built ltr 450's with the cherry bomb still plugged in. I run a pciii he is running a pcv. We both make about 55 hp 40 lbs tq


As far as maps go, that will depend on the climate and the fuel they are running. I found you have to go allot richer if you want to run avgas vs pump fuel. Plus every motor is going to run slightly different, that's why I would highly recommend that you go get a tune made for your bike on a dyno. Anything else will just be "close"
 
#25 ·
Thats what im thinkin based on my experiences with it 2005450r. And i understand that with the different octains it would throw a bunch of different variables in the fuel mapping (drz 250) but Both the maps i looked at were bbks with similar mods and running 110 leaded. And i cant imagine that the elevation would have that drastic of an effect on a fuel injected bike would it? I could be wrong about the cb but if thats the case then why is it that my pcv is being overrun by it?
 
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