Belly Tank Build Diary

[Mike Brown]

The factory blower ratio is 2.74:1 which at my maximum rpms gives a blower speed of 17,536 rpm.  My new blower ratio is 3.24:1 which gives me a blower speed of 20,736 rpm.  Both Weapon-X and Lingenfelter recommend a maximum blower speed of 23,000 rpm.  I should be safe at this speed.  This will stretch my fuel injectors to the maximum at the stock fuel pressure.  I am running an Aeromotive Eliminator fuel pump with boost referenced fuel pressure regulator so I will insure that I have adequate (higher than stock) fuel pressure at maximum power.  This is why a good tuneup on a chassis dyno is must. 

[Mike Brown]

I dropped the parts off to Weapon-X in Cincinnati to have the OEM blower pulley removed and the new pulley pressed on.  They recommend "pinning" the pulley to the shaft since it is held in place with a press fit only.  This is a comparison of the 3" OEM pulley and the Lingenfelter 2-1/2" pulley.  This will speed the blower up approximately 18%. 

[Mike Brown]

The SCTA has deemed that "D" rings are not safe to secure arm restraints like those on my SFI-20 fire suite.  The "D" rings can be used as an attachment point. 

[Mike Brown]

The fix is to use flat buckles like these to secure the adjustment.  Thanks to Joe Timney of Delaware Chassis Works for supplying these. 

[Mike Brown]

The fix took about 10 minutes. 

[Stan Back]

I'm at a loss to verify this reply – I've given away all my current Rule Books.  But, as I remember, somewhere it says that the arm restraint must be at the smallest place on the arm (which makes sense it that it won't move back and forth).  And some inspectors, not all, will not pass it when it's up on the forearm.  Comments?

[handyguy]

YES    ..  on smallest part of arm , generally the wrist area ..   STEVE

[Mike Brown]

The new blower pulley is pressed on so I need to machine another timing belt pulley to drive the alternator.  The only accurate way that I know to insure the new bore in the pulley is concentric when the hub is machined off is to bore and relieve softjaws for the lathe.  The slot prevents contact with the flanges. 

[Mike Brown]

The new pulley chucked up and ready to machine. 

[Mike Brown]

The new blower pulley machined. 

[Mike Brown]

The new blower and alternator pulleys installed.  The alternator pulley was a shrink fit on the blower pulley hub secured with Loctite.  After the Loctite cures I will drill and pin the pulley in place to insure that it does not come loose. 

[Mike Brown]

I'm at a loss to verify this reply – I've given away all my current Rule Books.  But, as I remember, somewhere it says that the arm restraint must be at the smallest place on the arm (which makes sense it that it won't move back and forth).  And some inspectors, not all, will not pass it when it's up on the forearm.  Comments?

The fire suit was manufactured by Stroud Safety.  The arm restraints are integral to the fire suit.  I was advised that Bob Stroud submitted for and received compliance. 

[wobblywalrus]

Mike, will that pull shaft stay cool enough to use Loctite?  Some types of it lose grip strength at elevated temps.

[Rex Schimmer]

Mike,
Are you planning to cross pin the pulley to the shaft or "Dutch" pin it? For something like this I really prefer the Dutch pin method as it is like putting in a precision key. When you have dis similar metals like you have you really need to do it with a small milling cutter, carbide if possible. This is a favorite way to key things together of the "Kansas Bad Man" Max Lambky.

Nice job on the soft jaws!!

Rex

[Stan Back]

"The fire suit was manufactured by Stroud Safety.  The arm restraints are integral to the fire suit.  I was advised that Bob Stroud submitted for and received compliance."

It (like mine) was probably in compliance when it was manufactured.  So we're following what I believe to be the "letter of the law" and we have a new strap located on the wrist with the proper hardware.  We were told to make that modification and used it all last year.  I'd hate to get to a meet and have a problem . . .