Anyone have numbers on what an intake manifold swap does for tbi engines?

[351FUN]

I'm not expecting much really. I have a scoop on my F250 with a race engine and all the scoop really does is make the engine filthy lol

 

[PlayingWithTBI]

I have a scoop on my F250 with a race engine and all the scoop really does is make the engine filthy lol

Ahhh I figured there was a Ford somewhere based on your "Handle" - good stuff!

Seriously though, I'd start from the tail pipe to the intake. If you can't get it out, you can't get it in! Ya know, the old in and out routine

 

[Schurkey]

In regards to swapping to a performance carb manifold with a tbi adapter plate... ...Does anyone have hands on experience

My '88 K1500 5.7L has aluminum heads with the old 6-bolt pattern on each side, not the TBI 6-bolt pattern where the center two bolt holes are at a goofy angle. I worked-out a way to use a ZZ4-style intake manifold. This manifold is just barely taller than the TBI manifold, and the TBI adapter plate puts the TBI unit just barely forward of the original position. Therefore the TBI is "up" and "forward" just enough that I had to pull some extra fuel hose up from the frame rail, and readjust the transmission TV cable.

GOOD LUCK getting functional EGR. That was my biggest headache. I had to piggyback two adapters--one commercially available and one I had to fabricate--to get the TBI EGR valve to clear the IAC motor.

There were a bunch of smaller items--figuring out how to mount the coil, how to route vacuum to the brake booster, how to get the heater-hose quick-coupler to mount to the manifold, where to put the EGR solenoid/EST module, etc. The only thing I still haven't resolved is fabricating a new A/C compressor-to-manifold brace, since this manifold doesn't have a boss for the bolt hole. The other two braces--alternator and belt tensioner--have provisions on the manifold that work good.

You've already got a cold-air intake system. All you need to do is remove the venturi restriction in the silencer, (I haven't bothered. At least, not yet.) and make sure that the temperature door on the air cleaner housing either works properly, or is deliberately disabled to the "cold air intake" position. (Mine works properly--I need it in fall, winter, and spring.)

I painted it black. Most folks would not notice that the manifold isn't original. There's clues, but people don't know what to look for.

 

[Schurkey]

Yeah, I know that the throttle blades aren't opening completely vertical with the pedal to the floor. I can manually open it further. So that's one thing I want to address when I get back to tuning.

Common for the lever arm on the throttle pedal to bend. Won't pull the throttle cable far enough before the pedal hits the carpet. I had that happen on my El Camino. Bend the lever arm that holds the end of the throttle cable "up", away from the firewall.

Best to weld a gusset or brace on that lever arm. If it bent once...it'll eventually bend again.

 

[Supercharged111]

Common for the lever arm on the throttle pedal to bend. Won't pull the throttle cable far enough before the pedal hits the carpet. I had that happen on my El Camino. Bend the lever arm that holds the end of the throttle cable "up", away from the firewall.

Best to weld a gusset or brace on that lever arm. If it bent once...it'll eventually bend again.

On my Camaro the accelerator pedal rod inside the car bent. It still got full throttle, but pedal height was a bit low for a heel/toe downshift.

 

[PlayingWithTBI]

Common for the lever arm on the throttle pedal to bend

On my Camaro the accelerator pedal rod inside the car bent. It still got full throttle, but pedal height was a bit low for a heel/toe downshift.

It's something to check anyway - when I get around to it

 

[351FUN]

Yup, the 351 got replaced with a 306 with over twice the power but 306FUN doesn't sound as good lol. Apast owner of the blazer took the cats out and ran 3" pipe but I think its still got the factory Y. I've replaced the muffler with a Borla but I think a full exhaust is in the near future. I'm not sold on headers yet though, but if it becomes essential it may happen when I do the summit heads.

 

[PlayingWithTBI]

I think its still got the factory Y.

That Y is quite restrictive, here's a picture of my SS mandrel bent JBA Y and a high flow 3" Cat. I later went to the 3" Borla Pro XS - gained even more HP.

You must be registered for see images attach

 

[351FUN]

That Y is quite restrictive, here's a picture of my SS mandrel bent JBA Y and a high flow 3" Cat. I later went to the 3" Borla Pro XS - gained even more HP.

You must be registered for see images attach

Flowmaster makes a very good Y that I've used on quite a few vehicles, its the only product they make that I recommend but its fantastic. I believe the pro xs is what I'm running but its been so long I can't recall.

 

[351FUN]

My '88 K1500 5.7L has aluminum heads with the old 6-bolt pattern on each side, not the TBI 6-bolt pattern where the center two bolt holes are at a goofy angle. I worked-out a way to use a ZZ4-style intake manifold. This manifold is just barely taller than the TBI manifold, and the TBI adapter plate puts the TBI unit just barely forward of the original position. Therefore the TBI is "up" and "forward" just enough that I had to pull some extra fuel hose up from the frame rail, and readjust the transmission TV cable.

GOOD LUCK getting functional EGR. That was my biggest headache. I had to piggyback two adapters--one commercially available and one I had to fabricate--to get the TBI EGR valve to clear the IAC motor.

There were a bunch of smaller items--figuring out how to mount the coil, how to route vacuum to the brake booster, how to get the heater-hose quick-coupler to mount to the manifold, where to put the EGR solenoid/EST module, etc. The only thing I still haven't resolved is fabricating a new A/C compressor-to-manifold brace, since this manifold doesn't have a boss for the bolt hole. The other two braces--alternator and belt tensioner--have provisions on the manifold that work good.

You've already got a cold-air intake system. All you need to do is remove the venturi restriction in the silencer, (I haven't bothered. At least, not yet.) and make sure that the temperature door on the air cleaner housing either works properly, or is deliberately disabled to the "cold air intake" position. (Mine works properly--I need it in fall, winter, and spring.)

I painted it black. Most folks would not notice that the manifold isn't original. There's clues, but people don't know what to look for.

I unfortunately don't have the factory intake. I could possibly track one down but open air cleaner and some kind of hood venting will do for now.

I'm not super familiar with EGR systems so I'll have to read up on if I want to try to keep it or not.