Sledpulling turbocharger rule writing 101

zstroken

zstroken

For $$$ your name here
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Sep 27, 2006
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I have seen this rule in several places, and think it should be clarified.

"

Turbocharger
: The vehicle is limited to a single
turbocharger; the inducer bore on the compressor
housing may be no larger than 2.8 inches
measured at the smallest diameter area of the
compressor wheel. A bushing may be used to
downsize the compressor housing ahead of the
wheel..... "​

How can you have a bushing in this class and it be effective?​

If I put an unmodded 3.0" wheel in my 3.0" turbo, and I have it
" measured at the smallest diameter area of the
compressor wheel " it will be 3.0. So you have basically defeated the rule of having a bushing correct?​

The rule should read something along the lines of "measured at the smallest diameter of the compressor inducer bore, must maintain x.x for 0.75 inches and be within 0.050" of the wheel, etc, etc.​

I don't think this is what the writer of the rule was intending for the turbo to be like. I am assuming they were wanting to have a 2.8 bushing class, not a 2.8 compressor wheel class. Have I missed something, cause I am just a dumb old boy, who has been called about trash talking behind others backs?​

​
 
Last edited:
I've seen it posted in rules both ways you listed. I usually use my best judgement and keep the grey area to myself. No matter who it favors.
 
mech2161 said:
I've seen it posted in rules both ways you listed. I usually use my best judgement and keep the grey area to myself. No matter who it favors.
Click to expand...


Usually the first statement is followed by the rules of the bushing, but it usually doesn't say "if a bushing is used change disreguard the measurement at the smallest part of the wheel"
 
I have the same question about this rule, it is the same as last year but to me this stats no custom covers? would you agree?

4. This class is limited to a single charger. The inducer bore can't exceed 2.60". This will be teched using a 2.65" plug, if the plug goes in you will be disqualified. No reducers of any kind permitted to make a larger turbo pass inspection. This also includes welding and remachining inducer bore to make a larger turbo pass. The stock map width enhancement (MWE) groove is allowed. no MWE groove wider than a 1/4" will be permitted. Twins are permitted as long as they are O.E.M. for that truck
 
outlaw99 said:
I have the same question about this rule, it is the same as last year but to me this stats no custom covers? would you agree?

4. This class is limited to a single charger. The inducer bore can't exceed 2.60". This will be teched using a 2.65" plug, if the plug goes in you will be disqualified. No reducers of any kind permitted to make a larger turbo pass inspection. This also includes welding and remachining inducer bore to make a larger turbo pass. The stock map width enhancement (MWE) groove is allowed. no MWE groove wider than a 1/4" will be permitted. Twins are permitted as long as they are O.E.M. for that truck
Click to expand...

I like this but you come to the problem that almost all turbo inducer bores are tapered.
 
outlaw99 said:
I have the same question about this rule, it is the same as last year but to me this stats no custom covers? would you agree?

4. This class is limited to a single charger. The inducer bore can't exceed 2.60". This will be teched using a 2.65" plug, if the plug goes in you will be disqualified. No reducers of any kind permitted to make a larger turbo pass inspection. This also includes welding and remachining inducer bore to make a larger turbo pass. The stock map width enhancement (MWE) groove is allowed. no MWE groove wider than a 1/4" will be permitted. Twins are permitted as long as they are O.E.M. for that truck
Click to expand...

That's why I brought this up in the other thread...the wording is a bit different than how most rules state it.

1) Who can legitimately tell if a cover has been machined in some other way than how it came stock? If the owner grinds off all the identifying marks, there is no way to tell if it's been further machined or not (other than doing it in such a way that it's painfully obvious) because you have no idea what the cover is or where it came from.

2) If the welding job is superb and is remachined, it would be difficult to determine whether it had been welded on or not (other than doing it in an obvious way).

So therefore it would kinda appear that this rule pretty much requires you to run a recontoured/re-trimmed wheel, with housing machined to fit.

Or am I reading it incorrectly?
 
what about housings that were 2.6 from dealer then they just open the back of the cover up to accept a 3.0 wheel I have seen this before, it looks factory because you cant see a weld or machine mark, you can tell there is a bigger wheel in it, but you cant get a 2.65 plug in it? would that cover fall under illegal in this rule?
 
Inducer and Exducer limits on any class seems to be a clear and obvious fix to all thes issues when writing rules, however noone chooses to use them.:bang
 
By the way the rules state, it doesnt clarify what they mean by larger turbo. If the inducer of the wheel fits into a 2.6 bore cover, then it sounds like it should pass. It never said anything about exducer size.
 
outlaw99 said:
what about housings that were 2.6 from dealer then they just open the back of the cover up to accept a 3.0 wheel I have seen this before, it looks factory because you cant see a weld or machine mark, you can tell there is a bigger wheel in it, but you cant get a 2.65 plug in it? would that cover fall under illegal in this rule?
Click to expand...


The way I read that rule, what you're saying is legal. See what everyone else thinks.
 
dieseljunkie said:
Inducer and Exducer limits on any class seems to be a clear and obvious fix to all thes issues when writing rules, however noone chooses to use them.:bang
Click to expand...

*bdh*

The organizations don't want to be bothered with checking wheels.

My opinion, anyone who can put together a competitive truck should know how to easily remove their compressor cover, but you'd be surprised at the number of people who whine about it.

So laziness wins.
 
nwpadmax said:
*bdh*

The organizations don't want to be bothered with checking wheels.

My opinion, anyone who can put together a competitive truck should know how to easily remove their compressor cover, but you'd be surprised at the number of people who whine about it.

So laziness wins.
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I say dont make the org responsible for it. Make the pullers responsible, ie. Tech the top trucks (in the money). If you dont want to pull off a hot cover at 2am then get to the pull early, remove the cover, and find tech. If not you lose PERIOD. IMO a lead seal would work well, then you'd be good for the season unless broken or tampered with. But laziness wins :thankyou2:
 
a housing that comes machined for the 3.0 wheel passes that rule. It has not been welded or re machined, it came that way!!!
 
outlaw99 said:
I have the same question about this rule, it is the same as last year but to me this stats no custom covers? would you agree?

4. This class is limited to a single charger. The inducer bore can't exceed 2.60". This will be teched using a 2.65" plug, if the plug goes in you will be disqualified. No reducers of any kind permitted to make a larger turbo pass inspection. This also includes welding and remachining inducer bore to make a larger turbo pass. The stock map width enhancement (MWE) groove is allowed. no MWE groove wider than a 1/4" will be permitted. Twins are permitted as long as they are O.E.M. for that truck
Click to expand...

those are last years rules....here is COTPC 2010's turbo rule they should look familiar.

Turbocharger: The vehicle is limited to a single turbocharger; the inducer bore on the compressor housing may be 2.6”. The inlet will be measured using a 2.65-inch plug or internal calipers. Bushing from any larger turbo size down to a 2.6 turbo is PROHIBITED. A stock map width enhancement (MWE) groove is allowed. No MWE groove will be allowed that has a width greater than 1/4 inch. All provisions allowing air to the wheel other than via the bore and the MWE groove are prohibited. 6.4 liter Powerstroke engines may utilize the factory twin-turbo configuration.
 
oh, I was confused I saw they already had the 2010 schedule and everything was updated for 2010, I guess the rules havent been posted yet, thanks. I guess this answer's my question, the housing im talking about it legal then.
 
outlaw99 said:
oh, I was confused I saw they already had the 2010 schedule and everything was updated for 2010, I guess the rules havent been posted yet, thanks. I guess this answer's my question, the housing im talking about it legal then.
Click to expand...

Yup your fine IMO!
 
Depends on the definition of a larger turbo I guess. If they say the turbo in the compressor wheel, then that would classify as remachining.
 
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