What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

throttlebody swapping

BlackBourbon

BlackBourbon

1/2 ton status
Joined
Jun 29, 2007
Posts
629
Reaction score
0
Location
Sherman, TX
i tried looking around but i need some help. here it is.....

motor is an '87 TBI350

this weekend i noticed the burb not running right and took a look under the hood. the drivers side injector was spraying halfass, then would drip a bunch and backfire, then stop, spray, etc.
i pulled the injector pod off and cleaned injectors real good. yadayada....
long story short, on the install i broke the throttlebody housing where one of the hardlines for fuel threads into it at the back.

my question to the injection gods here is....

1)should i find a whole used throttlebody for 350?
2)find just the 350 throttlebody housing and swap it?
3)is a 454 throttlebody a direct swap and good modification since it flows more cfm?
 
Last edited:
:dunno:

anyone?

calling 4x4HIGH.......

if all my questions are retarded, steer me in the right direction haha
 
My opinion is to just get another used one, and slap it on. If it doesn't work right, rebuild with your components that you know are good.

Don't waste your time on a 454 throttle body unless you've got the mods/HP to require it, and are prepared to spend the time/money on computer tuning it.
 
The injector pod is the same for ALL TBI units, the injectors are different for each engine size but the housing is all the same. I would hit the junk yard and buy another injector pod or if you don't want to hassle with that they can be bought for $40.00 from CFM Technologies.

I have used a place in Washington called Witch Hunter Performance to clean and flow test my injectors and they are 19.00 each for the service and a 10.00 return shipping. Their website says currently a 2-3 day turn around. http://www.witchhunter.com/
 
4X4HIGH said:
The injector pod is the same for ALL TBI units, the injectors are different for each engine size but the housing is all the same. I would hit the junk yard and buy another injector pod or if you don't want to hassle with that they can be bought for $40.00 from CFM Technologies.
Click to expand...

There are two different casting, the BBC and SBC, but the pod that fits in them (and of course the injectors) are interchangable between the two?

Going to need to get my hands on a BBC TBI unit, won't hurt to know. :)
 
dyeager535 said:
There are two different casting, the BBC and SBC, but the pod that fits in them (and of course the injectors) are interchangable between the two?

Going to need to get my hands on a BBC TBI unit, won't hurt to know. :)
Click to expand...

Correct, there is one TBI unit body that does everything except BBC and it uses throttle bores that are 1 11/16" diameter and then there's the BBC that has 2" throttle bores. The injector pods are the same between ALL V/6 and V/8 TBI's only the injector size is different.
 
So theoretically would it be beneficial to use the 2" 454 bores with the 350injectors for more flow? or would that cause tuning issues just by getting more air and not fuel? too lean?
 
BlackBourbon said:
So theoretically would it be beneficial to use the 2" 454 bores with the 350injectors for more flow? or would that cause tuning issues just by getting more air and not fuel? too lean?
Click to expand...

That would require a chip burn. Brian at TBIchips told me that it wouldn't work so i tried it just for the hell of it and he was right. :doah:
 
Exactly right on airflow. GM knew what the motor would need air-wise, so when you change what the system flows or fueling (pressure, larger injectors) it has to compensate as best it can.

This is why even changing to headers can benefit from tuning the chip. More airflow is more airflow, and fuel and air must continually be adjusted to make sure its optimum for the engine load.

The problem is worst at heavy throttle, as the O2 sensor can't be used to compensate for fueling. So if you are rich, or more likely (and more dangerously) lean, you typically won't know you are losing power or doing damage, and the ECM can do nothing to adjust.
 
Also remember the 454 throtle body needs more fuel so you will also have to upgrade your fuel pump to get the corect pressure behind it. My recomendation is find a old 1993 chevy capriece poliece car. It had 350 with tbi. get the throtle body and the ecm out and just plug and play. i did it to my 91 camaro when i did the 305 350 swap and holy hell it made a differance, then you can still use your o2 sensor. you may want to grab the spark controler as well
 
LOKI3006 said:
Also remember the 454 throtle body needs more fuel so you will also have to upgrade your fuel pump to get the corect pressure behind it. My recomendation is find a old 1993 chevy capriece poliece car. It had 350 with tbi. get the throtle body and the ecm out and just plug and play. i did it to my 91 camaro when i did the 305 350 swap and holy hell it made a differance, then you can still use your o2 sensor. you may want to grab the spark controler as well
Click to expand...

ALL GM TBI units run between 9-13psi with 12 being the norm and it's the same fuel pump. If you do heavy engine mods and need to run pressure any higher than 13psi THEN you need a pump capable of higher pressures.
 
True! But i was just assuming if you are going to run a 454 tbi setup and go through the re programing or get a ecm from a 454 vehicle you would have some prety hefty mods. i assumed and you know what that leads to!!!! I would still recomend looking into the copo ( poliece package capriece ) swap if you are runing a fairly stock 350.
 
Caprice cop injectors are a larger injector and will require a chip burn.
 
The 454 TB also requires thet you bore out the 350 intake manifold to the larger 2" bores or get an adapter.
350 intake is 1 11/16 bore.

FYI. I am running a bored TB (590 cfm) and 65 lb hr injectors on my stock 747 chip. with adjustable FP regulator. It works great.
 
Good tread. I have some personal experience to share. I think the 454 TBI is a good upgrade to do if you use an aftermarket "Performer" intake. I was on a budget so I bored my factory TBI intake to 56mm, and had a "Go Fast" machine shop radius / blend the larger bores. I am using the "Police 350" injectors ... according to the flow test done at Witchhunter where I had my injectors cleaned, my injectors flowed 74 Lbs at 20 PSI. I have programmed my ECM for 68 Lbs which is close what I think the "Police 350" will flow at the 12 PSI my pressure regulator is set to. I upgraded the cam in my 350 to the roller TPI camshaft and installed 1.6 roller tip rocker arms.

Can I keep up with the Dodge Hemi ... NO ... the Dodge Hemi can't keep up with me!:D

dave w
 
You must log in or register to reply here.

Latest Posts

Top Bottom