Hahn Stage 1 Turbo Info Needed

HayabusaPilot

HayabusaPilot

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Been learning quite a bit on the turbo side of things here. I have a 2007 'Busa with a Hahn stage 1 turbo. After reading all the posts on "boost creep", I wrote to Hahn. (The bike has over 20,000 miles on the engine, turbo'd since day 1). The bike is running rich, producing about 215 rwhp and the gauge shows boost in the 7-9 psi range. Hahn gave advice about porting the turbo and ended with " if you run a full exhaust system, then boost creep will not be an issue". I do run a full STOCK exhaust system for maximum stealth look and sound....is Hahn right or should I pursue a porting option as they initially stated? And would it be safe on a basically stock motor to pursue 225-230 rwhp through better tuning, fuel mapping? Thanks. ( And, yes, I basically know next to nothing about the turbo, but I can ride the bike. It tours great, has done a 201 mph GPS/radar run and catches most Gixxers off guard because of the bags and seats....)

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The hp does sound a little low for the amount of boost on a stock engine.....but hp numbers can vary so much between dyno's you might show 240-50 on another one. From what you've described, you've got some incredible mileage and tremendous reliabilty out of your bike, while still being able to have tons of fun when you choose to :beerchug: Personally it sounds like you have an awesome set-up.........I wouldn't change a thing :laugh:
I only hope my turbo 14 I'm building will run anywhere near as long, and as reliably, as your busa has :bowdown:
 
Thanks, just got a bit concerned on some of the Hahn info posts about internally wastegated boost systems. So far, so good with the bike. Goes to the Suzuki shop here in Tucson for maintenance like clockwork. And the other worry was overheating issues, but even multiple 2-up trips to Vegas and San Diego in June and July haven't (yet and hopefully won't) caused anything unusual. Does go through rear tires fast though!
 
your exhaust system is what is killing your hp.

8 psi on a hahn with its supplied exhaust would be 260-270ish...

restrict the exhaust and it drops severely. Fatten it up and it drops more.

If the bike isn't fouling plugs or putting you in the poor house between fuel or service work....ride it how it is and be happy.
 
Aaron at Hahn is correct in regard to porting the hot side (turbine) of their turbo. That will alleviate most of the boost creep you are experiencing. Your horsepower is low, even for a full exhaust, at the boost level you are seeing on the gauge. Although a dump pipe (and proper mapping) would increase rear wheel horsepower, you should still be seeing 250ish with the setup you have. You should port the turbo (Hahn will do it for you if necessary), and get it properly mapped . . .:beerchug:
 
if it runs fine, leave it alone. No need to port anything, you haven't said you are experiencing boost creep, you are concerned about it.

8psi should yield more than 250 with a dump pipe and good tune
 
Thanks for the replies. The bike has averaged 40 mpg since it was built and I'm not seeing any fouling on the plugs. We haven't done any drag racing type runs, it's always roll ons into the turbo. (with a few front wheel lifts in the low gears when boosting, usually when throttling hard from about 40 mph in 1st and and staying in it a bit). Evan Steel Racing in Tucson stated a better tune would increase h/p, although reading some posts here now has me trying to learn the air/fuel ratio that will allow longevity for the bike without burning up the motor... I've been bitten somewhat by the horsepower bug by reading info here, but am not willing to give up the stock exhaust look as the bags were built around the pipes. And the stock motor will withstand 225-250 h/p without internal mods? Suzuki4life...probably the best advice, just leave it be! My wife was thrilled with that answer as she thinks the bike doesn't need any more h/p.
 
HayabusaPilot said:
Thanks for the replies. The bike has averaged 40 mpg since it was built and I'm not seeing any fouling on the plugs. We haven't done any drag racing type runs, it's always roll ons into the turbo. (with a few front wheel lifts in the low gears when boosting, usually when throttling hard from about 40 mph in 1st and and staying in it a bit). Evan Steel Racing in Tucson stated a better tune would increase h/p, although reading some posts here now has me trying to learn the air/fuel ratio that will allow longevity for the bike without burning up the motor... I've been bitten somewhat by the horsepower bug by reading info here, but am not willing to give up the stock exhaust look as the bags were built around the pipes. And the stock motor will withstand 225-250 h/p without internal mods? Suzuki4life...probably the best advice, just leave it be! My wife was thrilled with that answer as she thinks the bike doesn't need any more h/p.
Click to expand...


bike will withstand 300-320ish hp without any internal mods.
 
BTW...beautiful bike.

Hahn racecraft wouldn't been my choice for turbo systems (even though I have owned a few of their kits)

But the dual exhaust is a dream of mine and the bags make the perfect sleeper.

BUT....we must step into the real world with the modern liter bikes and realize that a 550 lb bike with 230 rwhp and bags...might hold its own,but won't show them up the way it would had in 02.

love the bike man :thumbsup:

who fabbed the exhaust?
 
Love the stealth look. On average you would gain about 15-20hp with out the exhaust system. You are getting good HP so if you like the look and feel, keep it the way you have it. Make sure you have good Bosst gauges, A/F guage and a fuel pressure guage. You will not have to worry about boost creep if all the guages are working.
 
Thanks again for the info on the engine. The exhaust was fabricated by Exhaust Works here in Tucson and the turbo was installed by the lead mechanic at Ridenow Powersports. Initially it was taken to Phoenix for tuning at Performance Cycles, then looked at again here in Tucson. The Hahn turbo kit had been recommended on a web board by two 'Busa owners in Phoenix ( an '02 'Busa and '04 'Busa) who claimed the kit was easy to install, easy to hide and that they'd had no heat related issues. They stated they'd had the turbos on for 3 years and 1 year respectively. I looked at the Hahn site, spoke to Ridenow and that's how the kit happened. Another friend of mine found this site and told me of it at a Bike Night out here and said there was lots of info on turbos I might want to see. Some of the reviews on the Hahn system here got me to thinking, so I wrote to Hahn and then posted here to see what experienced turbo drivers thought.
 
suzuki4life said:
if it runs fine, leave it alone. No need to port anything, you haven't said you are experiencing boost creep, you are concerned about it.

8psi should yield more than 250 with a dump pipe and good tune
Click to expand...
I agree...if its running fine and getting good mileage leave it be :thumbsup: The way its set up it'll probably give you years of big grins :laugh: This time your wife could be right :lol:
 
Thats a great looking bike and the perfect sleeper! Keep it the way it is and ride it till she turns 100,000 miles.:thumbsup:
 
IMHO...a fuel gauge is a must....then an a/f......then a boost.

I run fuel and boost but my bike came like that and too lazy and cheap to put an lm-1 on it
 
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