Hahn Stage II Gen I Busa
- Thread starter Shaft
- Start date
Well, let's see. First big weakness is the mild-steel header pipe, which uses separate flanges (one for each pipe) and goes on good when it is brand new. If you ever have to remove it after it has been heat cycled a few times, you will find that the individual pipes don't line up with the exhaust ports any more. A lump hammer is handy! The other thing about a mild steel head pipe is that it cracks, usually after about a year of use. I had one that actually dropped the turbo while it was on the dyno . . . that would not have been too good in the street, dragging a turbo under the bike by it's hoses. That is why POWERHOUSE sells a stainless replacement header for Hahn systems.
Another weakness is the internally-gated Mitsubishi turbo. Although the actuator is designed to pull off the gate at around eight pounds of boost, these systems tend to spike to ten pounds . . . the small flapper valve style gate is not large enough to do any better.
The log style plenum does not come with any tie-down straps, and can blow off the throttle bodies at around 15 pounds.
On the positive side, the Mitsu turbos spool quickly and you get good throttle response and actually a nice-running bike when properly tuned. Keeping it at the lowest boost level is the key to happiness with a Hahn. If you ever have a desire to turn up the boost, it gets complicated.
Improving the Hahn setup requires the optional stainless steel header and an external wastegate mod. By the time you've done these two things, you have already spent the amount it would have taken to buy an RCC system.
1busa
Registered
When it comes to something like a turbo don't compromise.... Save your $$$ do it right with the right parts the 1st time and you will save a whole lot of $$$ and headaches in the long run. Been around this forum and a few others long enough to know cheap and turbo in the same sentence doesn't end well 
I would say do not compromise in an effort to turbo the bike.
arthur39
Registered
you should call them directly, I spoke to them recently and they told me they are no longer using the mitsu's. I was hoping to get another chra from them. The kits might be different then what they are showing. I've heard mixed reviews on the port fueling system. Some people have made decent power with it, others say it is a POS. I heard Powerhouse might have a refurbished RCC kit, maybe you could get secondaries added to the plenum and an a microtech to control the boost. That would be the way to go, unless you plan on doing a lot of the modifications yourself.
Shaft
Registered
They also sent me an email and they are updating their kits. They are calling it a precision turbo kit.
I was very curious on the port fueler system as it looks pretty slick
Yes the refurb I'm considering as soon as my funds clear up more and the exchange rate isn't so messed up for us Canadians. I was thinking of that kit + the Port fueler system + boost controller.
I was very curious on the port fueler system as it looks pretty slick
Yes the refurb I'm considering as soon as my funds clear up more and the exchange rate isn't so messed up for us Canadians. I was thinking of that kit + the Port fueler system + boost controller.
Arthur39 is correct - they are no longer using Mitsubishi turbos, they are using Precision turbos, which happen to have a problem smoking all the time. If they would have stuck with the Mitsus, and gone to a Super20H Shootout turbo with an external gate, it would have been a home run, IMO. As far as their Port Fueler, it is funny that you ask, and here is why:
When the Port Fueler was initially conceived by Bill Jr, we were very exited. The concept of putting another injector directly in the port that way was a great idea at the time. As one of Hahn's biggest motorcycle dealers, POWERHOUSE was asked to do all the Beta testing on the Port Fueler before it hit the market, which we did. The crappy re-labled control box he supplied did NOT track properly - it would go in 1,000 rpm jumps in the software. This resulted, for example- in a situation where the afr would be right on target at 7.000 rpm and right on target at 8,000 rpm, but dangerously lean at 7,500 rpm (as an example). Hahn thought that was okay, we did not. I told him at the time that his idea was good, but the "split second" controller he was using (which was made for a car) was a pos. I refused to sell it. Hahn is a nice guy, but he is a car guy and has his head somewhere else when it comes to bikes. I don't see too many people using his car kits, either.
That, coupled with the fact that his tech assistance is non-existent, and that even dealers have to email him was a no-brainer for us. I personally contacted Richard at RCC, and found a quality product and a breath of fresh air. That was 16 years ago. POWERHOUSE has installed and tuned Hahn, Mr. Turbo, and even Velocity kits along the way, among others. Ask me what I run on my personal turbo Busas . . .
Do yourself a favor - learn from other's mistakes, it will save you time and money. And yes, we do have a great refurbished RCC turbo system for a Gen 1 right now. A few people have contacted me about it, but no one has pulled the trigger yet, so it is still available.
Shaft
Registered
Thank you again Frank for your input. This is all great information.
