TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

EGR ??????????

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Old Feb 22, 2007 | 06:31 PM
  #1  
Gallileo60's Avatar
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From: Texas City, Texas Area
Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
EGR ??????????

What are the drawbacks of removing the EGR system on a TBI car??????? I will have the chip burned to do away with it, so no number 32 code....Do you gain anything at all by doing this???? Do you loose anything??? Not worried about testing...Thanks, Tom
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Old Feb 22, 2007 | 06:59 PM
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
You don't gain a thing, you lose some gas milage, and your pollute more.
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Old Feb 22, 2007 | 07:57 PM
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From: Texas City, Texas Area
Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Dewey do you lose milage only when cold, or all the way around....If I really lose much perhaps, I will tell him not to disable it, and I will get the truck EGR, since I am geting a cod 32 after I put on the 3 inch exhaust...Thanks...Tom
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Old Feb 23, 2007 | 08:34 PM
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From: Quebec
Car: '89 Firebird
Engine: 305 TBI (LO3)
Transmission: 700R4
Axle/Gears: 10 bolts 2.73
Yep , lot of gas mileage ...
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Old Feb 24, 2007 | 12:31 AM
  #5  
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From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
The reason why you get a code 32 EGR after putting on a better exhaust system on a TBI car, is the TBI system uses a normally open EGR valve, while the TPI cars use a normally closed EGR valve. The TBI system needs some exhaust backpressure to keep the valve closed when not in use. The better flowing exhaust keeps the valve open when it shouldnt be and sets the code 32. The fix is to VERY CAREFULLY drill the vacuum orifice in the EGR valve one drill bit size larger, so it gets more vacuum to close. I think this has been mentioned before, so try searching to see what size drill bit you need.
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Old Feb 24, 2007 | 01:29 AM
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From: K.C. Mo.
Car: '89 GTA 9,000 MILES
Engine: 350
Transmission: 700R4
Axle/Gears: 3.27 9 bolt
Fix it if you like. Contrary to popular belief you will not lose ANY mileage. I have blocked and /or completely eliminated EGR on multiple vehicles.

As far as pollution goes if the engine is properly tuned you are not hurting the environment. Before someone's inevitable meltdown over my comments please be advised there are many vehicles since the late 90s without EGR and AIR pumps. If the vehicle is properly tuned including trimming the A/F ratio you won't hurt anything and you won't lose any mileage whatsoever.

As FAR AS GAINS.... a cold air charge makes the most HP. Removing the hot EGR air charge from the incoming air will certainly help the engine make more power. Some will chime in here about the timing being altered under certain EGR open/close conditions. This has never been an issue on any of my vehicles with a completely blocked EGR. If you are concerned the timing table could be altered.

Another Gain IMO is stopping the buildup of Carbon and sometimes oily, greasy nasty mess inside the intake tract directly related to the EGR.

Last edited by Jetmeck; Feb 24, 2007 at 01:36 AM.
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Old Feb 24, 2007 | 06:53 AM
  #7  
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From: Texas City, Texas Area
Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Jetmek, your answer makes more sense to me..I know in the past I have even used block off plates on some V-8's...But never on a computer controlled vehicle...Im not sure if there would be much effect when the motor is warm....Well if I dont like it, I guess I can put it back on......Thanks to all, Tom
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Old May 17, 2007 | 01:53 PM
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From: michigan
Car: 1985 TransAm
Engine: 5.0L TPI
Transmission: 700R4 auto
Axle/Gears: 3.27 BorgWarner
Re: EGR ??????????

i just baught a 89 trans am with a caprice cop car 350 in it so the cam is slightly better but i keep getting code 32 as well i think im just going to go custom on the ecm
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Old May 18, 2007 | 09:28 AM
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Re: EGR ??????????

Originally Posted by Jetmeck
Fix it if you like. Contrary to popular belief you will not lose ANY mileage. I have blocked and /or completely eliminated EGR on multiple vehicles.

As far as pollution goes if the engine is properly tuned you are not hurting the environment. Before someone's inevitable meltdown over my comments please be advised there are many vehicles since the late 90s without EGR and AIR pumps. If the vehicle is properly tuned including trimming the A/F ratio you won't hurt anything and you won't lose any mileage whatsoever.

As FAR AS GAINS.... a cold air charge makes the most HP. Removing the hot EGR air charge from the incoming air will certainly help the engine make more power. Some will chime in here about the timing being altered under certain EGR open/close conditions. This has never been an issue on any of my vehicles with a completely blocked EGR. If you are concerned the timing table could be altered.

Another Gain IMO is stopping the buildup of Carbon and sometimes oily, greasy nasty mess inside the intake tract directly related to the EGR.
this really cleared up my answers. cause I was about to block off the egr, now Im sure I want to! Cause it will be dyno tuned also.
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Old May 18, 2007 | 11:30 PM
  #10  
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From: kansas
Car: 89 S10 Blazer
Engine: 355 tbi
Transmission: Built 700R4 w/ 2500 stall
Axle/Gears: 3:73 posi
Re: EGR ??????????

Originally Posted by golden
Yep , lot of gas mileage ...
no need to be sarcastic.

Thanks kevin for the egr trick, ive been debating what to about the egr b/c we were going to take out the cat on the silverado, i was also thinking of the positive pressure or was it negative pressure?....egr valve, but drilling a hole seems easier.
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Old May 18, 2007 | 11:57 PM
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From: Hurst, Texas
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: EGR ??????????

Originally Posted by Jetmeck
Fix it if you like. Contrary to popular belief you will not lose ANY mileage. I have blocked and /or completely eliminated EGR on multiple vehicles.

As far as pollution goes if the engine is properly tuned you are not hurting the environment. Before someone's inevitable meltdown over my comments please be advised there are many vehicles since the late 90s without EGR and AIR pumps. If the vehicle is properly tuned including trimming the A/F ratio you won't hurt anything and you won't lose any mileage whatsoever.

As FAR AS GAINS.... a cold air charge makes the most HP. Removing the hot EGR air charge from the incoming air will certainly help the engine make more power. Some will chime in here about the timing being altered under certain EGR open/close conditions. This has never been an issue on any of my vehicles with a completely blocked EGR. If you are concerned the timing table could be altered.

Another Gain IMO is stopping the buildup of Carbon and sometimes oily, greasy nasty mess inside the intake tract directly related to the EGR.
Contrary to your statement, I have worked more than one vehicle with and without EGR. The EGR equipped vehicle seems to get 1-2 MPG better consistantly on the highway than the non-egr equipped vehicle. It is pretty simple why. The exhaust gases are an inert gases, meaning they won't burn. EGR gases do not affect air/fuel ratios on the engine. Therefore when the valve opens, the EGR is recycled into the engine. The intake manifold vacuum drops and the engine is then fighting less of a battle pulling in its air/fuel mixture. This means the engine does less negative work, which improves its effeciency.

Clogged EGR passages on my 2.8 TBI in my GMC Jimmy killed my mileage by more than 4 mpg highway.

My Van was consistantly able to knock down 2 mpg better with EGR than without.

Probably my worst case EGR situation is in a 6,000# vehicle with a huge engine. When I purchased my 1994 Dodge 2500 truck with the 8.0 V10 (Regular Cab/Longbed/Auto/2wd/3.92 Gears), the vacuum hose between the EGR solenoid and the EGR valve split open. The first tank gave me a SES light and 8 mpg in highway driving. The truck seemed to run sluggish and rich. I went through the truck and tuned it up. Drove it another tank and got an astonding 8 mpg highway and it still seemed sluggish at highway speeds. Found the split in the EGR vacuum hose on the underside of the hose. Replaced all the vacuum hoses. The truck ran alot better on the highway using ALOT less throttle than before. The fuel mileage improved to an amazing 17 mpg. To this day(325,000 miles), I still get 17 mpg highway from the beast.
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