Engine/Transmission (1998.5 - 2002) Boost fooler questions

[maint.man]

At what psi. will a fooler be nessesary ? I have 18. 5 psi. at W. O. T. currently , and will be adding a set of 40 h. p. BD injectors. I've heard that if I set a code that the truck sill go in to "safe " mode , and I'll have to have the code reset . I just don't want to have to baby it with the extra power there.

Thanks,

Brent

 

[TomGolden]

I do believe that all the 24 valver ECMs will freak out at just slightly over 20PSI of boost, so if you are going to add bigger injectors, you'll easily be able to push past the 20PSI barrier. Look around for a used EZ if you don't want to fork over the $ for a new one right now. The EZ has 3 settings - I think the lowest setting is basically little to no extra fueling, but it acts as a boost fooler on all 3 settings.



Tom

 

[GarrettPetersen]

yeah I think it is around 20 PSI. I know you can set the code with just a boost elbow. I did it myself. But I got lucky and my truck didnt go into "limp" mode.

 

[CFAR]

Is there a rule that says you have to install the boost elbow that usually comes with new injectors?



Cause I didn't, my boost will not go over ~20psi no codes.



I didn't install the elbow because I don't have the comp w/built in fooler installed yet.

 

[3dracer]

I can pull just at 23 lbs. with my 98'5, and it is not setting any codes that I am aware of.

 

[TomGolden]

The boost elbow is also needed to get above the 20PSI mark. When I installed my EZ a couple years ago, it didn't come with a boost elbow, and I couldn't get over 20 PSI. I posted that question, was told "you also need the elbow". I replied "What elbow???" A member of the NW BOMBers (Bob Wagner I think... ) was kind enough to get me an elbow since my EZ didn't come with one.



As soon as I installed the elbow, it was able to get boost numbers in the 30+ PSI range



If I understand their operation correctly, they fool the wastegate of the turbo and therefore keep it from opening as soon as it normally would. So if your wastegate is set at 25 PSI, with no elbow, no matter what your injectors and box w/boost module might get you to, your wastegate is gonna open at 25 PSI and that's all you're going to get. The elbow bleeds off a little of the pressure, so you're really making say 35 PSI, but the wastegate now only sees 25... or something like that anyway.



Tom

 

[RustyJC]

Originally posted by CFAR

Is there a rule that says you have to install the boost elbow that usually comes with new injectors?



Cause I didn't, my boost will not go over ~20psi no codes.



I didn't install the elbow because I don't have the comp w/built in fooler installed yet.

Just out of curiosity, since you're running bigger injectors with no increase in boost pressure, what kind of EGT's are you seeing?



Rusty

 

[n7gxz]

Tom,



You are close on how the turbo/wastegate work. The wastegate is in the exhaust or turbine housing. What happens is when the compressor side reaches ~20 psi the actuator starts opening the wastegate allowing exhaust to bypass the turbine pin wheel thus slowing down the compressor. When an elbow is installed to slow down or block the pressure feed to the actuator the pressure will increase. Once the pressure goes over ~20 psi the ECM will start to defuel the engine in an effort to reduce the pressure. At this point is when a code will be set. To prevent the code being set a boost fooler is needed, either a dedicated one or one that is part of a fueling box like the EZ or later VA.



Clear as mud now, right?

 

[CFAR]

Just out of curiosity, since you're running bigger injectors with no increase in boost pressure, what kind of EGT's are you seeing?

Well let me see, cruising along at 65-70 = 600*-700*

Wot at about 45mph holding it down I can reach 1200* by the time I'm at 90mph with one shift in between. Kind of hard to do this with my weak clutch.



If I take it easy I don't smoke or experience what I would call high egt's.



Of course on the speed run described above, I would also be at 0psi on the fuel gauge. So I don't

 

[maint.man]

So , unless I misunderstood , The boost fooler is a have to have item. The injectors that I got didn't come with a boost elbow , but better safe than sorry .

Thanks to all

Brent

 

[maint.man]

So , unless I misunderstood , The boost fooler is a have to have item. The injectors that I got didn't come with a boost elbow , but better safe than sorry .

Thanks to all

Brent

 

[ACoyle]

1) Boost elbows have a restriction and slow the buildup of boost pressure to the diaphram that will bypass the turbine. the result is more boost.



2) Places that I know of that boost elbows come from. In the kit with the boost fooler. With a "box". From several helpful TFR brothers.



3) I am told that boxes like the EZ don't really come alive till the elbow goes on.

 

[CFAR]

PLAIN ENGLISH TRANSLATION:



You need neither a boost elbow nor a boost fooler!



Someone correct me if I am wrong, you are only running 40hp injectors, so you should'nt have a high egt problem. Which is the main reason to run higher boost pressures, besides bragging rights of course.



Adding injectors will not cause you to have higher boost.



A boost elbow will.



So if you get a boost elbow you will need a boost fooler.



I have never heard of limp mode.



However your truck will defuel if it sees psi's above 20 and you will set codes.



If you are going to buy a boost elbow and fooler, you might as well save $$ and just buy a box. Most will have both included. That is assuming you intend to buy a box in the future.



But for just the injectors you have I wouldn't worry about it.

 

[andrewkoperdak]

You should set a code at or around 22 PSI. The boost elbow permits going past 22 PSI. The Boost fooler tells your ECM that everything is fine.

I have Stage III injectors (100 HP) and have experimented with the fooler and elbow. With everything installed I have gotten as high as 31 PSI pulling a hill and my trailer (4000 pounds). I set a code at 31 PSI. I believe it was code #0246. I took my boost elbow off and ran my truck up a hill. MY boost stopped at 20 PSI and my EGT exceeded 1300 degrees. My normal temp on the same hill with Boost fooler, elbow and injectors is 1100 degrees. You can see the elbow and fooler are necessary. The EZs, if I am not mistaken, come with the Fooling written into the code and the elbow should come with the fueling box.

You don't need to spend hundreds of dollars for a new or used EZ to enjoy you injectors but I would recommend buying an elbow to allow your engine to make more boost pressure and a fooler to prevent setting any PSI related codes.



Regards,

Andy

 

[TomGolden]

Actually, larger than stock injectors do contribute to higher boost. Larger than stock injectors get more fuel into the cylinders, or at least optimize the atomization of the fuel, thereby allowing more complete combustion. More fuel in the combustion process (or better combustion) produces more/hotter exhaust gasses, which in turn spin the turbo more, which produces more boost.



A boost elbow by itself does not cause higher boost levels, rather it allows the turbo to make more boost by "fooling" the wastegate into not opening as early as it would without the boost elbow.



Now with fairly small injectors, it is possible that you would need neither the boost elbow nor boost fooler, and you still may not pass the important ~20PSI mark where the ECM will defuel and set codes. Maybe... . I went right from stock to DD3's so I have no personal experience with the smaller injectors.



Also, be careful, as not all fueling boxes have a built in boost module. The Edge Products boxes all do I am quite certain, but I believe the Van Aaken does not... ?? I am not sure about the Blue Chip or TST boxes. Be absolutely certain before purchasing, new or used.

 

[maint.man]

Many thanks gentlemen, I guess i'll try it with out the fooler and elbow , and if it sets codes or gets warm i'll move on from there. I've been informed of a fooler for sale , and will decide this weekend what i'm doing. Thanks for the education.

Brent

 

[Hohn]

Elbow- "fools" wastegate to allow higher boost

Fooler- hides higher boost from ECM, so no codes



w/o the elbow/fooler combo bigger injectors will spool the turbo faster, but not produce more boost since it's cut off at 20psi.



elbow/fooler is only necessary with stage 2 or higher injectors, OR ANY injector with a box. .



Hohn