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Increasing air to the TBI

  
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Increasing air to the TBI

 
cam91go cam91go
New User | Posts: 11 | Joined: 07/13
Posted: 07/31/13
04:58 AM

What changes will I have to make if I increase the amount of air to the Throttle body. Right know the cold air is picked up from a thin opening across the front of the hood on my 1991 Camaro. At first I thought the hood wasn't fitting properly.I have the opportunity to make a ram air system, but I don't know how this will effect all the sensors and computer?
Dave  

redneckjoe69 redneckjoe69
Enthusiast | Posts: 388 | Joined: 04/10
Posted: 07/31/13
03:01 PM

i doubt you'll have to change anything at all.    the MAP sensor and computer will make adjustments accordingly.  

68scott385 68scott385
Enthusiast | Posts: 669 | Joined: 05/09
Posted: 07/31/13
05:09 PM

Ram air is not forced induction. Studies show that air is not forced into the engine by forward motion until approximately 150mph.  
68scott385 68scott385 68scott385

cam91go cam91go
New User | Posts: 11 | Joined: 07/13
Posted: 08/01/13
03:40 PM

Have you driven a 1991 Camaro lately. 150mph + is no problem. And even though the systems are cold air induction,it was called Ram Air by the factories. Ram Air III, Ram Air IV by Pontiac,Ram Air Induction by AMC, etc,etc. Thank you for your input,but it does not speak to the question asked!  

waynep712222 waynep712222
User | Posts: 103 | Joined: 03/13
Posted: 08/01/13
08:35 PM

well.. hmm... i am taking that you have the TPI tuned port injection version of the 91 camaro.. not the TBI throttle body fuel injection version...

increasing air flow.. i don't recall what the inlets looked like on a 91 F body with the TPI motor...

do you have any vacuum gauges or a combo gauge used for testing fuel pressure and vacuum.. you might hook that to a tiny hole in the side of the inlet duct.. and take it for a run with the gauge under a wiper blade.. so you can see it..

if it does not move much.. you might want to search out a HVAC magnehelic gauge set.. it does the same thing with 2 different ports..  to actually measure air flow..

if you are an electronics person.. there is an electronic way to measure it thats cheeper actually...

most 1996 and newer OBD2 cars have a fuel tank pressure sensor installed usually in the cover of the fuel sending unit.. 3 wires..  this is a pressure and vacuum sensor thats probably limited to about 10 inches of vacuum and 6 or 8 inches of pressure.. i don't recall the range on these.. as i rarely get into those diagnostics.. but you can .. with a 9 volt battery and a 5 volt IC voltage regulator build a pressure sensor to change the voltage on a digital volt meter or better yet a digital storage scope..  with that you can easily monitor the air pressure or vacuum.. and if you blow the sensor.. its off to the junk yard for a pile more of them..

professional mechanics use this set up with the sensor on a radiator pressure tester cap adaptor..  this way they can remove the fan belts on cars/trucks with belt driven water pumps..  hook up an inductive lead over the #1 spark plug wire and start the engine.. they can see the TINY pulses of compression when the head gasket is blown that get into the cooling system..  yep.. that accurate..

i have a friend who runs the salt flats and other events.. i have wanted him to install some of these light weight sensors around the car to measure air pressure on the body to know where to perform changes..

so. there are some ways to know if you need to make changes...

please also think about rain and water splashed up from other car intrusions.

my friend lost the engine in his mini cooper.. he was fording the flooded intersection on san fernando road and tuxford street out in sun valley. he made it just about thru the very deep water. until a big 4x4 came splashing thru.

filled the air box with water.. when he accelerated out of the puddle.. it filled the engine with water before it could drain..  

redneckjoe69 redneckjoe69
Enthusiast | Posts: 388 | Joined: 04/10
Posted: 08/02/13
05:58 AM

is this what your factory set-up looks like?

040402 061100


  i dont see a problem what your trying to do.
   
  T.P.I. motors respond real well to installing an adjustable fuel pressure regulator, and cranking the pressure way up.  

redneckjoe69 redneckjoe69
Enthusiast | Posts: 388 | Joined: 04/10
Posted: 08/02/13
06:03 AM

heres a link about cranking up the pressure and dyno results.   one of the best mods you can do to a TPI engine, IMO.

http://www.thirdgen.org/optimal-fuel-pressure  

redneckjoe69 redneckjoe69
Enthusiast | Posts: 388 | Joined: 04/10
Posted: 08/02/13
06:06 AM

heres an example of one.

http://www.summitracing.com/parts/bbk-1714  

68scott385 68scott385
Enthusiast | Posts: 669 | Joined: 05/09
Posted: 08/02/13
09:02 AM

Icon Quotecam91go:
Have you driven a 1991 Camaro lately. 150mph + is no problem. And even though the systems are cold air induction,it was called Ram Air by the factories. Ram Air III, Ram Air IV by Pontiac,Ram Air Induction by AMC, etc,etc. Thank you for your input,but it does not speak to the question asked!

Since you do not comprehend let me put it in easy terms. The engine will not ingest any additional air with a ram air or cowl induction or whatever other name you give it until you are doing 150mph. Below that all you are getting is cooler air. You may gain some hp from the cooler air but the sensors may also increase the amount of fuel being pumped in depending on how much cooler the air is. This may affect your gas mileage but if you are driving 150mph regularly, gas mileage is the least of your problems.  
68scott385 68scott385 68scott385

cam91go cam91go
New User | Posts: 11 | Joined: 07/13
Posted: 08/02/13
10:23 AM

I don't know what happened. The reply was sent before I was finished. Sorry I don't know if it was completed so I will do it again. Let's see if I comprehend the way an engine works. The more air and fuel you can put in and out of the engine, the more power it makes. Turbos, superchargers, high lift cams,bigger carbs,hi rise intakes,headers all serve that purpose. If an engine requires 600 cfm's of air,it will run on 500. If the air cleaner is restricting the flow of air below the maximum needed for peak power, it will still run. Now in simple terms, all I am asking is WILL the computer,sensor or whatever compensate for the increase in available air. Look it up, a 305 came with TBI. Only the 350's had Tuned Port Injection (your picture)  

waynep712222 waynep712222
User | Posts: 103 | Joined: 03/13
Posted: 08/02/13
12:45 PM

1991 Chevrolet Camaro RS:
Available engines
6 Cylinders T 3.1L MFI OHV
8 Cylinders E 5.0L TBI OHV

or

1991 Chevrolet Camaro Z28:
Available engines
8 Cylinders 8 5.7L FI (found in 37% of 1991 Chevrolet Camaro Z28)
8 Cylinders F 5.0L FI (found in 63% of 1991 Chevrolet Camaro Z28)

the VIN 8 or the Vin F motors were TPI...  

redneckjoe69 redneckjoe69
Enthusiast | Posts: 388 | Joined: 04/10
Posted: 08/02/13
02:56 PM

Icon Quotecam91go:
I don't know what happened. The reply was sent before I was finished. Sorry I don't know if it was completed so I will do it again. Let's see if I comprehend the way an engine works. The more air and fuel you can put in and out of the engine, the more power it makes. Turbos, superchargers, high lift cams,bigger carbs,hi rise intakes,headers all serve that purpose. If an engine requires 600 cfm's of air,it will run on 500. If the air cleaner is restricting the flow of air below the maximum needed for peak power, it will still run. Now in simple terms, all I am asking is WILL the computer,sensor or whatever compensate for the increase in available air. Look it up, a 305 came with TBI. Only the 350's had Tuned Port Injection (your picture)

for what its worth, that pic is a 305 tpi motor.   if you wanted more help, you should be more specific.    

   so,...we have a 150mph, 305, tbi motor,...correct?     do some car crafting, make you air intake syststem, see if it runs better or worse,...any check engine lights come on?    i think you'll be fine.  if not, put the old system back on.  got any pics?  
    there's some good and knoweledgable people on here, they've pointed out they're opinions.   a before and after chassis dyno results would be interesting.    ive seen threads like this before and the problem is you cant really, accurately, duplicate the wind going down the road at speed.    i guess the only way to tell would be repeatable drag strip times?
    i say, "go for it!"  

cam91go cam91go
New User | Posts: 11 | Joined: 07/13
Posted: 08/02/13
06:12 PM

My original question was specific. Will the computer or air sensor or whatever controls the A/f mixture, compensate for an increase in air flow to the throttle body. Simple enough. The first response was "it should" that's what I was looking for. How that progressed to Mud-bogging, a series of reports  on pressurizing at 150 mph is a puzzle. Your final statements " see if it runs better" is what I was trying to avoid. As I stated before, if it was a carb system , I would decide. By looking at the coloring on the plugs, and the tail pipe in some cases. I asked if the computer would handle the change. All that was required was a specific yes or no!
Thank you all for your time
Dave  

68scott385 68scott385
Enthusiast | Posts: 669 | Joined: 05/09
Posted: 08/03/13
09:40 AM

The flaw in your theory is the notion that because the engine is now exposed to fresh air that it will inhale more.

This is the third time I've tried to say it.

If you have already modified the motor in such a manor that it now breathes more than it would in stock configuration then you need a better air intake tract than that supplied by the factory. If you have not modified the motor so that it breathes more than it would in stock configuration, a fresh air/ram air set up will not introduce any more air into the motor than the factory intake tract, it will just introduce cooler air to the motor. And yes, the engine's sensors will change the fuel map for the change in intake air temperature.  
68scott385 68scott385 68scott385

cam91go cam91go
New User | Posts: 11 | Joined: 07/13
Posted: 08/03/13
06:36 PM

Time to give up. We're talking apples and oranges. Cold air verses a restrictive air intake. Obvious, the people at K& N air filters are wasting our time and money by selling less restrictive air cleaner filters. Their claim of increased horsepower due to more air getting into the carb/fuel injection are unfounded. All I origionally wanted was to know is, will the computer richen up the system if more air is available to be injested by the engine due to the removal of the restrictive air intake opening. You know like replacing a dirty air filter  

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