first turbo bike need advise

busakiller

Registered
hi guys so I bought stage one turbo busa and I need some help with some problems iam having.

03 busa stock motor

stage one mr turbo kit
old pc3
stock wheelbase
5 up rear sprocket
fuel system
auto meter boost gauge

those are the mods on the bike.

on to my problems.......

bike make 4 to 5 psi in 3rd gear same with 4th 5th gear. I haven't opened up all the way in 5th and 6th. bike gets a little tank slap happy in top gears. 1st gear it makes like 2 psi and 2nd gear it make 3 psi. had the bike dynod and it only made 178 hp at the tire. I have done a boost leak test and the throttle body shaft seals are leaking pretty as soon as the system get pressure built up. that's the only leak I have found.

so my questions are why is it low on power?
why does it not make full boost in 1st and 2 nd gear?
can the boost leak cause it to be low on horsepower?


things I do plan on doing.
upgrade to pcv
a/r gauge
fix boost leak if I can figure out how to do it.
 
Definitely fix the boost leaks. While you may be getting pressure, your losing air volume. If the afr is super fat you'll be killing power. But 178 seems really low. Like even it it was at 10.5 I would still expect it to make at least 200hp with 4psi and a overly fat tune. Sure it doesn't have a base spacer? On a healthy engine and tune, I would expect to see around 220-230hp @4-5psi. Something's up.

Does it have an external wastegate? If it does, it's worth pulling the spring out to see what ones in it. If it's a 4psi spring, 4-5psi would be normal.

I would also strongly suggest going back to stock gearing, or even -1 from stock in the back. Higher gearing will load up the engine more helping to spool the turbo harder. You'll also notice the bike will pull way harder due to the engine being held in peak torque for longer. Also helps with wheelies to an extend since your stock wheelbase.
 
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I do plan on changing the rear sprocket to 2 up in the rear since I already have one laying around in the garage.

I do want to fix the boost leak. but I dont know how to change the seals and I haven't found any place that can do it locally.

this weekend I will pull the wastegate spring and see what one it is.

the local tuner said bike should make at less 200 at 4 psi. I hope with the boost leak fixed it will make more power.

I will do a compression check on the bike this weekend also
 
Street bike yes :) Really fun for roll ons. Spinning is a little more controllable when you add in a little more room. For instance, I did a mock launch the other day on a back road with 8" back, spun so bad I went back and looked and the patch went across 2 lanes but I didnt know it was really that bad as it was happening. I just knew i was spinning and doing everything I could to keep it straight. Take to the track and the windscreen will be hitting you in the faceshield instantly. Plus it gets old seeing stock stretched out $500 swing arm guys tear you a new one just because of launch.
 
You have no issues with your '60 ft or 1/4 mile times either. So your 300hp street bike is a fun street bike. For you.
 
I tried it and would have stayed with it. Got tired of the windscreen bustin me in the helmet and the kids with the grudge bikes with stock motors stretched to bejesus whipping my ass.
 
I tried it and would have stayed with it. Got tired of the windscreen bustin me in the helmet and the kids with the grudge bikes with stock motors stretched to bejesus whipping my ass.

Come on man don't let the kids get to you...
For me running swb has been looked at as a challenge. A challenge to see what my best will be then maybe move up to a 6" or 7" stretch. I know many people that have stock or near stock bikes with 12-16in stretches running good times but it is what it is. People think I'm crazy for even riding my bike around with the stock arm on it, to me that shows the lack of knowledge most people have about turbo bikes.
I do agree with you though, if you want to have the best 60ft times and better e.t over all, stretch the bike.
 
I see what you are saying. Challenging yourself to go as fast as the bike possibly can with YOUR skill before making a change on the bike to make it quicker. Thats a noble thing. And a patient thing.
 
update

the bike is back to stock gearing and makes full boost in 2nd gear now. still wheelies in 1st and 2nd gear...... so over winter I will extend it 6 inches and get a shinko hook up for the rear. I am going to get the throttle bodies shaft seals replaced with o rings and find out what wastegate spring is in the wastegate. I would like to up the boost to 7 psi to get to that 200 rwhp mark. I just need to do some looking around and find a good tuner.
 
update

the bike is back to stock gearing and makes full boost in 2nd gear now. still wheelies in 1st and 2nd gear...... so over winter I will extend it 6 inches and get a shinko hook up for the rear. I am going to get the throttle bodies shaft seals replaced with o rings and find out what wastegate spring is in the wastegate. I would like to up the boost to 7 psi to get to that 200 rwhp mark. I just need to do some looking around and find a good tuner.


Tuner checking in, where are you located?
 
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