throttle body spacers

[jmderyke]

i have a 86 2.5L4 and i was wondering if throttle body spacers are worth the money, are any gains from them? Also i haven't found any for the 86 2.5L4 will other spacers work from different years?

[Jakeman17]

I have a TBS in my 88 4.0L. Came with it when i bought it. not really sure if it makes a difference or not

[mnkyboy]

I wouldnt expect much from a spacer.

 

I would be suprised if you could find one for a TBI 2.5L, they are more common on MPFI engines.

[dasbulliwagen]

I read somwhere that one for a 4.0 will work... it was a Power Aid 4.0 spacer PN 310-510.... they said it will bolt right to the 2.5. and that the spacers work better on TBI setups than they do on port injection setups like the 4.0 has. If you get one and notice any difference let us know, I'm contemplating one for my 2.5 as well.

[MiNi Beast]

it isn't worth the money for any noticeable gain in performance unless you use in with other air mods such as adding a header and cat back exhaust system. and even then let it be the last add on you buy.

[jmderyke]

thanks for the info and part number, I did some home work and learned they are for lower torque and throttle response at lower rpms.

[jmderyke]

ok i did some gasket part crossing on rockauto.com and found that the 4.0 spacer will work for the mpi 2.5l but they didnt start using mpi on the 2.5 until 1991.

[Pete M]

gearing is where the greatest improvement comes. :thumbsup:

[Automan2164]

The best results from spacers will be found on TBI setups... THe purpose of a spacer is to mix and increase the volume of available fuel air mix. So on a MPI, where fuel comes in just before the head, it won't do much... But on a TBI, it stirs the fuel air mix before entering the manifold, and will increase volume, equaling a more noticeable, but not much, gain in performance.

 

TBI, go for it. MPI, get something else.

Rob L.

[Eagle]

The best results from spacers will be found on TBI setups... THe purpose of a spacer is to mix and increase the volume of available fuel air mix. So on a MPI, where fuel comes in just before the head, it won't do much... But on a TBI, it stirs the fuel air mix before entering the manifold, and will increase volume, equaling a more noticeable, but not much, gain in performance.

Well ... you're close.

 

A throttle body spacer CAN'T increase the volume of air. How much air gets sucked in at any given RPM is determined entirely by the bore, stroke, and camshaft specs. The air path from the inlet of the throttle body to the intake valve on the head is nothing but a pipe, and the spacer just makes the pipe longer. Yes, there's more air in the pipe, but that doesn't put any more air through the intake valve per revolution.

 

What the spacer can do on a TBI is, as you stated, increase the turbulence and thus enhance the mixing of the fuel droplets with the air column flowing through the manifold. And that's why there's more benefit from a spacer with a carburetor or throttle body injection than with MPFI, because with MPFI the column of air in the "pipe" is dry, and the fuel doesn't get injected until the air gets to the intake valve.

[comanche87]

:agree: with eagle. Its all air till it hits the head. I did get one for my 87 mj with 4.0 from rustys and that was my second mod on my truck after the cat back exhaust i did. I did feel a noticable difference in it. It had a swerl grove inside the spacer which turned the air while going through the intake into the head.

[Darren]

A throttle body spacer is an overpriced paper weight.

[kar120c]

:agree:

[veritas4156]

I have always thought that they were a waste of money but in my digging at the junkyard today I got one and the guy decided not to charge me for it, so no money wasted. Once the weather is consistently cold, I'm gonna run two tanks of gas and record my fuel economy without it, and then do two tanks of gas with it. I'll report fuel economy and if I notice any difference in power. So keep your eyes open around January.