[Jogon30]

Ok guys, I'm sorry if this question has been asked before I did search but was not able to find the answer? My question is, will the dobeck ejk work without a aftermarket exhaust ? Will u still get some proformance out of it ? Is there anyone out there running it this way?

[NMKawierider]

I can't say but here's my thoughts. I already measured 4psi peak back pressure with the stock exhaust on mine when I was looking for reasons why the springs were not holding things together. Replacing some of the springs and doing my exhaust end mod was my effort to keep it together and bring the pressure down. Without the spark arrester in it the back pressure was reduced by more then half but went too lean as the system could not adjust the injector's pulse-width far enough. Had I kept it as it, I would have needed to install a programmer to richen it back up...and it would have added even more power...but decided now wasn't the time.

Adding one to the stock exhaust as is may give you at least some more power but will also increase the back pressure even more then it is now. Will that have an effect on valves...and exhaust flanges.... probably. I guess this is why programmers and freer flowing exhaust kinda go hand-in-hand with EFI systems.

I would also be interested in hearing from anyone running a programmer on the stock exhaust system. 

[Bobbed06]

I spoke with a fella that has done nothing but race his Z force from day one. Its on mile 700 ish now. His exact words was the only mods are a DynoJet PCV and air filter. They tried the 2 brothers exhaust and removed it, said it lost too much back pressure and power. Reinstalled stock muffler, and left air filter and Dynojet unit in place. Their 800 runs like a champ and pulls other racers outta the hole by 2 bike lengths.

He also said, they change ALL fluids day one to premium, and that their buggy has been beaten absolutely every mile of its life. No failures to date.

[Jogon30]

I'm really about to pull the trigger on a two brothers pipe and ejk but  want to hear from somoe of you that have them! What gains have you seen ! Do u get more speed? Take off? Top end? Just give your opinion please. Thanks guys

[flash]

Hey jogon, I've got the dynojet and two brothers along with a twinair filter, I love the sound of the exhaust, but it sure seems like I lost a little power, I never ran it hard during the breakin period.
After around a hundred miles I added the exhaust and dynojet, now it seems like around 6700 rpm is all it will turn now, I've been looking for a different map for the dynojet but no luck, I've got the tune from dynojet for mods I got.
So I don't know if exhaust helped or not.
I would love to see a dyno test with and without the exhaust.

[Jogon30]

That's crazy mine buggy is pretty fast as it is now and with the b2 setting even better but I did ride it hard during break In. I have been  looking for some ejk setting and what works best but have had no luck but thankfully I got lucky and live in the same town as nmkawi and I'm already thinking when I get my stuff I'll head over and we will go loco on the tuneing lol. Maybe rent the tool and see if we can't figure this out! If any one is running this set up what settings are you useing ?

[flash]

Yea I ran it sorta hard but never flat out, it's got around 300 miles on it now.
It's been trouble free and it's pretty fast as it is, I've thought about putting the original exhaust back on to see if it  would make a difference.

[Jogon30]

Yea I ran it sorta hard but never flat out, it's got around 300 miles on it now.
It's been trouble free and it's pretty fast as it is, I've thought about putting the original exhaust back on to see if it  would make a difference.

That's not a bad idea you should do that I mean it's easy to do and run it let me know the outcome of you do please.

[NMKawierider]

I pulled my silencer off to see if it had an effect on mine. It shouldn't have but it felt a little more tame the last time out with it. Maybe just my ears...lol

[Jogon30]

I guess I need to do more research lol. its just hard to find info out there on these machines.

[flash]

Yes it is, I wish there was a dyno report on these with and without the exhaust.
Anyone wanna take one for the team....lol
I wish I had access to a dyno, would really like to know.

[Spaceman78]

I added my 2 Bros. before doing anything else. I could feel a slight difference. Acceleration seemed to be a little better in a short run. The EJK helped more, even though I still don't know if I have the settings right. I can't tell any difference with the Uni. I plan to do snorkels soon. I hope opening up the intake makes a difference.

[Jogon30]

Spaceman? What settings Do u have the ejk? They say it's allready set for stage 1. Did the settings it comes preset to work pretty good? What did u change?

[Spaceman78]

I'll have to check my settings. I can't remember what they are now. The standard settings didn't work for me. It lost power compared to the factory setting. I just kept bumping it up a little at a time and test driving it until I thought it felt best. I increased fuel on all 3 levels and adjusted the accelerator pump to open quicker. I'll try to remember to check soon to see what I finally left it on.

[Jogon30]

Ok cool