I was wondering before my rebuild how well these things work.. i never got to the research but now im to that point where i guess i should do it.. so im doin the research..

while i do this i was just wondering if any of you guys had one or an opinion on these things?.. also how good of gas milage do u get on one of these spacers if anyone has experiance with one?..

i guess no responded because they are not all that.. gives you like 4-12 hp.. a little fuel economy.. not reall worth the 70-110 bucks for a minor upgrade..

I know they were used pretty regularly in the carbureted days. I never really did any research then to see if they were all that useful though.

Increasing the plenum volume in a GM tbi motor is important for performance. I put a 1" spacer on my '95 Chevy G30 van with a 350 tbi/4L80e along with an injector spacer, and a "soup bowl" which un-shrouds the injectors. I don't know how much the increase was by the numbers, but it had a good seat of the pants increase. I would guess 10-15 hp, with no change in mpg. Remember that was on a heavy 1 ton van. You should be able to find all this stuff for under $150.00 between ebay, Jegs, and Summit. And for a 10-15 hp increase that is cheap and easy.

[You must be registered and logged in to see this link.]


[You must be registered and logged in to see this link.]

I quote Blackfoot from the other forum:

"The gasket between your injectors and TB, Get 2 of the thick ones and double them up. You need a die-grinder to remove a little from the back of the venturi so the injectors clear.

My brother did this a few years ago on his pickup and what a huge difference it made. So I gave him a call and he came over and helped me do mine. My 92 will roast the back tires from a dead stop and lay 30+ feet in full posi now. That is without power breaking, Just stop, and stomp on it. I get the same mileage as I did before but gains a bunch more power and throttle response. All it is doing now is mixing the fuel better before it hits the intake runners."

I haven't had time to play with this little mod yet myself

How difficult would this be to do?

More power is never a bad thing.

Can you post some pics? I have had the TBI unit completely apart, and am not visualizing the gasket(s) you referring to.

I believe he is referring to the gasket between the TBI unit and intake manifold.

[You must be registered and logged in to see this link.]

If that worked properly they are talking about the top left gasket in the picture. It is for were the injectors mount to the TB itself.

The spacer for that is in the second link that 200OZ posted if anyone takes the time to look

One of the mods that I am doing this winter is having some 1" TBI spacer blocks machined. I'll keep you guys posted.

I did that on my 88 TBI Jimmy back in the day. I remember it giving me more midrange power and better throttle response. I was really impressed with how much it helped.

Is there clearance under the wagon hood for it? I know it's pretty tight in there. Especially if you have a caddy intake. IIRC, that intake actually hits the hoodliner...

so a 12"long 90 deg venturi spacer would really make a tbi wake up eh? sorta like a cross ram?? then it,d make almost as much power as,. say,.. a briggs and stratton??

Nick

Since I'm running a 14" Air cleaner on mine, I can say I don't have the clearance for a spacer.