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Old 12-27-2017, 12:52 AM   #6
DailyDriverSst
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Default Re: Throttle Stop w/ 1 blade TB / roll RPM Q

Quote:
Originally Posted by Tom Goldman View Post
The problem you have with a large bore single blade is closing it far enough to get it to actually slow down the air flow enough .
I have closed the throttle of some EFI Stock Elim .cars to where the TPS is at 55 -60% and all that happens is we loose a little 60' but the car actually makes it back up between the 330 and 660 clocks.
Like Lenny said you need to go closed farther , maybe not to idle but I would say at least down to 25-35% open .
This is exactly why I asked. I know the issue came up in Pro-Stock, and has also been dealt with on the flying toilet.

This is exactly the info I wanted to know. Yes it will be FOL for index racing, and CL for driving back and forth to the local track and around town (trailered any further). The tuner and platform has proven well in similar builds for bracket racing in various areas, including a track champion up north. But he does not run a stop with his single 68mm blade, and is slower than 6.95 (small displacement OHC NA motor).

With that said:

This will be a very low boost procharged engine with A2A. There are others with a similar combination running at 8-10 pounds and running very close to the SG index in grudge racing. Knowing how centrifugal boost can vary widely with atmospheric conditions, I'm hoping that I can drop down to 4-5 pounds as a baseline, then adjust the stop as per normal use to get to the 10.85-90 window.

The good thing with centrifugal is that I do have a couple options to work with. I know a few T/D guys are using manually/timer activated BOV's to dump at the big end. By nature, centrifugal is only making boost at high RPM. Essentially, I can hang the BOV open on the 2 step and on the stop, and keep the engine completely out of boost until it comes off the stop - unless I do as stated above and hit the timer at the 60'. I feel that this would help with the consistency factor.

It will take some time to learn the curve, but this is more of a fun project than strictly for SST. Goal is to run the 2019 DragWeek street class without the stop, and bracket race and SST with the stop. Trying to make the build be as versatile as possible.

A 4150 is bolt-on, as will a 2 barrel TB, but an elbow and LS/Ford style TB will be much easier to package with the piping.

Last edited by DailyDriverSst; 12-27-2017 at 12:59 AM.
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