Thread: Big Bore Sonic Booms
07-15-2007, 06:20 PM #1
Big Bore Sonic Booms
I have my first set of Big Bore Sonic Boom throttle bodies almost ready to test. They measure 43mm at the blade, and have a 6 degree taper bore from the blade up to the mouth of the throttle body where they measure 43.75mm.
Taper boring has been proven to outperform a standard straight bore. They will be finish ported and outfitted with velocity stacks just as the originals are.
These will flow 15 percent more air than the 40s will. The equivalent from going to an 800cfm holley carb to a 930 cfm holley carb..
Testing will begin hopefully this weekend on my Lowell big bore, and i will also test them on my unported 1300 06 ski to see how they work on different applications..
Of course i will be offering this combo for sale in the near future. It is not cheap. There is no cheap way to do it correctly and i will not compromise price for quality.
It will take your set of throttle bodies, approximately 2-3 weeks turnaround time, and also your rubber spigot intake manifold boots to port match them to the throttle bodies..
Package pricing will be around 900.00 complete, all parts labor and return shipping.
I will not be actually selling these untill i test them and make sure they perform as expected.
If you are interested then PM me so i can get an idea of how many people may want a set.
Once again, this is still in the preliminary stages, and it is not something that is done in 3 days like the porting of the 40s are..
07-16-2007, 02:01 AM #2
Nice to see you got a set ready for testing! I can't wait to see the numbers.
07-19-2007, 09:55 AM #3
07-19-2007, 09:59 AM #4
very clean looking Ross, Can't wait to hear your results!!
07-19-2007, 10:12 AM #5
I see big gains here Ross.Cant wait to hear the results.
07-19-2007, 11:03 AM #6
07-19-2007, 01:52 PM #7
damn Ross you need to clean under those finger nails cant wait to see you run them sunday the TB's that is
07-22-2007, 09:37 AM #8
07-22-2007, 09:47 AM #9
very nice work
Looks like a good compliment to all the 1390 cc motors out there !
07-22-2007, 08:19 PM #10
Ok, just got back. Heres the summary..Idle quality was outstanding, after spending what seemed like an eternity re-synching all 3 blades by using water as a flow measuring tool, it was a complete success. Everything changes with bigger blades and bore, the idle throttle angle is far less, which requires a huge difference in the positioning of the TPS switch.
Driveability was great. It actually seemed to tame down the 4700-6200 jump in rpms the 1390 has. Throttle response was very crisp and clean, no hesitation.
Since my 79.0 at the bug ive been stuck in the mid to hi 78s here in tampa salt. I made 2 passes today at 79.4, and 2 more went 79.3.
The highest rpm ive ever recorded previously in the summer heat was 7259, heat soaks would take it down generally to the 7220s.
Today i recorded a 7290, several heat soaked 7260-7270s..
These comparisons were against the 40mm sonic booms i installed at the bug...
I ran my EFI controller at 11-11-11-5.5
I was happy to see we have plenty of fuel, my iridium plugs which dont show color as well as a standard plug were a dark brown/black color, beyond tan, very much on the rich side. I didnt change the settings all day, wanted to stay rich and safe.... Maybe there is a little more from leaning it some. It appears so by reading the plugs..
This was a good day, its always nice to step forward...
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