Stroking an inline 4 Turbo

nhgunnut · 10-20-2009, 07:37 PM

A question for the engineer types here.
I am Running a Hahn Turbo Kit and Port Fueler (Secondary Fuel Rail) On an Otherwise Stock 05 Busa. (Last Dyno Run showed 257 RWHP and 139 Ft pounds of Torque Peak torque at 6k. ) I have been counseled by people a trust against punching out a Street turbo as the tend to blow out head gaskets regularly. Up until recently a custom stroker crank at about $2700 was out side of my budget. But I have found out I can use a Gen 2 crank and pick up an extra 10mm of travel for a bump to 1340. (My cost on a new gen 2 crank is just shy of $750 the build gets completed at a local shop for just under 2500. Now on a normally aspirated Gen 1 with a stock fuel system and PC3 this has proven to produce an extra 8 to 10 horse the big gains have been with a slight degree of the cams and extra 12 to16 foot pound of torque. Logic seems to indicate that between the turbo and the fuel rail increases to be as much as 30% higher with the added side effect of the extra volume of exhaust gases causing the turbo to reach boost levels sooner.
IThe more I explore this the better I like it. But if we have folks here who can see a problem with this I would like to know. I appreciate your time. Rick

10-20-2009, 07:37 PM	#1
nhgunnut gun totin redneck Join Date: Apr 2008 Location: South West New Hampshire Moto: turbo busa 999 Duc Goldwing & Victory Posts: 1,130	Stroking an inline 4 Turbo A question for the engineer types here. I am Running a Hahn Turbo Kit and Port Fueler (Secondary Fuel Rail) On an Otherwise Stock 05 Busa. (Last Dyno Run showed 257 RWHP and 139 Ft pounds of Torque Peak torque at 6k. ) I have been counseled by people a trust against punching out a Street turbo as the tend to blow out head gaskets regularly. Up until recently a custom stroker crank at about $2700 was out side of my budget. But I have found out I can use a Gen 2 crank and pick up an extra 10mm of travel for a bump to 1340. (My cost on a new gen 2 crank is just shy of $750 the build gets completed at a local shop for just under 2500. Now on a normally aspirated Gen 1 with a stock fuel system and PC3 this has proven to produce an extra 8 to 10 horse the big gains have been with a slight degree of the cams and extra 12 to16 foot pound of torque. Logic seems to indicate that between the turbo and the fuel rail increases to be as much as 30% higher with the added side effect of the extra volume of exhaust gases causing the turbo to reach boost levels sooner. IThe more I explore this the better I like it. But if we have folks here who can see a problem with this I would like to know. I appreciate your time. Rick __________________ Evolution requires a body count, Count or be Counted!

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