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Old 02-18-2013, 06:48 PM
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Restrictor plate

So if I put a restrictor plate on my 350 to limit the top speed, do I now have to rejet the carb to correct the mixture? Or is it more like running at 3/4 throttle?

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Old 02-18-2013, 10:59 PM
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the restrictor plate might not slow you down.
why not put a rev limiter on the car?wire the ignition to limit the rpm(with a chip)in high gear only
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Old 02-19-2013, 11:53 AM
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Quote:
Originally Posted by vinniekq2 View Post
the restrictor plate might not slow you down.
why not put a rev limiter on the car?wire the ignition to limit the rpm(with a chip)in high gear only
Im with you on the rev limiter Vinnie. However our class says restrictor plate over 283 CI. Good old APBA, They do it thier way. BTW this is 16 foot Jersey Skiff with 355 Chevy power
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Old 02-19-2013, 12:36 PM
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If you are racing,then do the math first,,,then buy a restrictor plate cam and go racing.
would love to see the rules and what variants you are allowed
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Old 02-20-2013, 07:50 AM
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Vinnie X 2! I wanna know the "rules", too.

Jim
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Old 02-20-2013, 08:07 AM
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Well here yougo:
Safety Inspection - All boats must be inspected prior to entering the course. Inspections will take place on
Friday from 9:AM to 5M. It is the responsibility of the Owner/Driver to contact an inspector, hand him
the inspection sheet that is in the registration packet, and sign the APBA safety inspection sheet with
APBA number or APBA single event membership number. Jersey Skiffs must be equipped with a
0.125" minimum restrictor plate if CID is greater than 305. Lifting slings must be date tagged and
load rated within the last 3 years. Kill switches are mandatory. Secondary throttle return springs must
be present. Prop shafts

The truth is, its not really competition as much as it is to just show off!! No 1st or second places, no flag start, no checkered flag. Just the opportunity to run our skiffs. The question was put forward because a couple of the guys refuse to put restrictor plates on claiming they have to rejet, retune, Blah blah blah. My thought was its more like running a small carb or 3/4 throttle.
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Old 02-20-2013, 09:54 AM
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remember when Nascar first brought in restricter plates and a certain person was bullet porting the plate underside and actually going 10 mph faster.
Some manifold manufacturers experimented with a bullet on the intake floor.some work.
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Old 02-20-2013, 10:59 AM
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Why not just "adjust" the carb so that the secondaries don't open all the way?

No loss of power except at WOT and on the high end.
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Old 02-20-2013, 11:15 AM
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Quote:
Originally Posted by toddalin View Post
Why not just "adjust" the carb so that the secondaries don't open all the way?

No loss of power except at WOT and on the high end.
carbs work most efficiently at W O T
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Old 02-20-2013, 11:56 AM
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Quote:
Originally Posted by toddalin View Post
Why not just "adjust" the carb so that the secondaries don't open all the way?

No loss of power except at WOT and on the high end.
YeahIdont make the rules, Soft touch rev limiter would have been my idea. Decide what speed they feel is "safe" and chip accordingly. 6300 would be about 70 MPH.
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Old 02-20-2013, 11:58 AM
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Quote:
Originally Posted by vinniekq2 View Post
carbs work most efficiently at W O T
Engines work most efficiently without restrictor plates too.

Limiting the secondaries would accomplish his goal of reducing the ultimate power at no cost and without even removing the carb from the manifold. Plus, when he finds that he misses that power, it is the easiest to reverse. Finally, he can ultimately determine how far the secondaries should open to get the desired level of power. With a restrictor plate, it would be harder to "dial in."

It would be simple enough to do this and drive the car for a while to see if you can live with the loss of power.
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Old 02-20-2013, 12:07 PM
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carbs

Quote:
Originally Posted by toddalin View Post
Engines work most efficiently without restrictor plates too.

Limiting the secondaries would accomplish his goal of reducing the ultimate power at no cost and without even removing the carb from the manifold. Plus, when he finds that he misses that power, it is the easiest to reverse. Finally, he can ultimately determine how far the secondaries should open to get the desired level of power. With a restrictor plate, it would be harder to "dial in."

It would be simple enough to do this and drive the car for a while to see if you can live with the loss of power.
what I am saying is :
the blades of the carb need to be square/vertical at W O T to get the best mix,have the venturis do their job,not have a distorted flow path through the curve....

the restrictor plate has no effect on direction of flow like a partially closed blade

as I also posted,a bullet nose spacer can in some situations actually increase flow.This is why I asked about the rules.
also a soft touch rev limiter might help,until someone builds a long stroke engine.
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Old 02-20-2013, 05:08 PM
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The way to slow them down is by restricting the exhaust. The local left turn track does this.
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Old 02-20-2013, 05:24 PM
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So we are limited by a strictor plate, do I need rejet or not?
Rev limiter and throttle stops not an option, I didnt make the rules. Its stupid anyway, we not really racing!! You have to understand the APBA and thier dislike for the jersey skiffs. No limit on the Hydros, run what you brung!
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Old 02-20-2013, 05:29 PM
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any changes are likely to be minor
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