Posted: 9/2/2007 6:09:55 AM EDT
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Alright folks, this is a question for the mechanics and engineers here. I am running an 05 Busa with a Hahn Stage 1 turbo kit. I would like to get a bit more low end torque and my budget is not huge so swapping in another turbo kit seems out of the picture. I have a thought (more of a guess really) that If I went with an over bore kit the increased volume of gasses moving thru the turbine would begin to build boost sooner. What is the opinion of the more educated and experienced engine builders here? |
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You've seen pictures of my buddies bike, iirc about the same setup you have. He put a cheap adjustable boot regulator on it and is running 7-9 PSI now depending on the gas he can find. It was at 6psi before. Boost doesn't come on any quicker but he said it makes it bit better when he hits 6k RPM. There is a guy named Dick Datsun that is somewhat of a turbo guru, he was experementing with CO2 pumped into the exhaust before the turbo, pretty much instant boost. Personally I wouldn't bore or stroke a turbo bike without first messing with the turbo. -JTP |
I am running a 8 pounds now and in street tune getting 235 rw hp. I have in the past tuned it to 250 but it takes to much out of the low end and the it becoms for lack of a better word twitchy. Since I ride this bike more often then not on my 50 mile commute to work my goal here is a daily drivable street beast. |
I have tried a 2 tooth drop on the primary in the past. It then became a very "buzzy" bike without some of highway characteristics I like. This is to be my winter project. I also have a budget and at the moment what seems to make the most sense is to increase displacement. Ideally stroking the engine would be best but the cost of a custom crank and rods is prohibitive. On the other hand a 1397cc big bore kit with J&E turbo pistons is right around $1200 (after getting your $700 core charge back for the block) add gaskets and dyno tuning and we are at the 2k mark. Some questions I need answers to are will the stock fuel rail feed this thing sufficiently? Do I need to think about a different fuel pump to maintain sufficient fuel pressure Does my Power Commander have the range to handle the change in displacement? Should I think about a cam change at the same time thus further altering the power curve? |
Do you miss your wife?  May I ask why you want more torque? I haven't ridden a Busa, but it has to have crazy torque as is. |
I want more torque simply because I want it.(Call me self indulgent) I am running stock pistons without any spacer. I like the idea of a "Muscle Bike" So more torque at the low end before the 4500 mark where the boost hits. Or a means of bringing the boost on sooner. am beggining to explore the idea of switching from the Super 16g to the Super 20g |
I love Superchargers I ran one on a modified 13b rotary. But when I was building the Busa could not find a Blower kit for the Busa that had a decent relablity record.. The 400 Hahn is all top end |
Swapping out to entirly different kit would bust the budget for this project. But most of the stage one kits offer roughly the same power profile. The math keeps taking me back to a big bore kit |
