I was thinking of just going to my local wrecking yard and finding another 2.8 TB. I have questions:
1) should I get a 2.8 TB
2) is there cleaning of anything needed?
4) could I use a 3.1 or 4.3? would I want to?

Thanks.

 

Try to get a 2.8L one. Other ones need some modification to work right. And I really dont think a 4.3 would work, but im not sure about that.

You can clean it up if you want.... only thing needed is gaskets.

 

3.1 won't work without swapping the upper plenum, TPS and IAC wiring connectors (in most cases), and the PCV valve-to-intake tube along with re-routing other vacuum hoses... The IAC passages are different.

 

My 3.1 has the same upper Plenum as a 2.8.
The PO of my car did a buttload of evil to the car. Broke the same tps Screw off in the throttle body. He then broke a few exhaust studs. Have a major exhaust leak, sounds a Harley. Would be fine if I didn't live somewhere where the neighbors get easily pissed off. The Seafoam treatment got police AND fire dept called. The cop has a monte ss so he knew what Was up. He just laughed about the smoke. Then when I asked if all the light were a parade for me.

 

I sincerely doubt it as NO 2.8 EVER came with the MAP sensor vacuum fitting on the rear left of the plenum. Maybe the TB and idle air parts changed, but there was NEVER a MAP fitting on the plenum as the 2.8 NEVER HAD a MAP in the F-body except 82-84 carbs. It may look the same (it's similar), but trust me, it's not.

 

I'll take a pic of mine tomorrow. This is my second 92 v6 and they both have the same upper . I've been in wrecking yards and the 2.8 are identical to mine.
The throttle bodies are different. I'll try and get pictures.

 

2.8 and 3.1 plenums are almost identical 3.1 dosent have the round badge on top and the 3.1 plenum has one extra fitting on the back iirc

the plenum has nothing to do with the iac passages

the difference between a 2.8 and a 3.1 intake is this

the 2.8 lower has a spot for the cold start injector, were the cold start injector is there is a passage to each cyl , this passage is also were the aic air goes

it runs down the tube from the 2.8 tb and into the lower intake


now onto the 3.1 intake manifold
it has no provision in the intake base for the cold start injector nor does it have the passages in the base for the coldstart fuel/ and aic air


the 2.8 throttle body iac passes air from the front of the throttle blade to the top of the tb were it runs down the big plastic hose to the lower intake

the 3.1 tb iac bypasses air directly around the throttle blade


u can use a 3.1 tb on a 2.8 if u cap off the vacum line on the back of the intake manifold and also switch over the iac pigtail and i belive the tps pigtail , not sur eon the tps sensor pifgtial but i know deffinatly the iac connectors are different. the car may or maynot be harder to start when its cold since the fuel from the cold start injector wont have air moving in the passage to help move the extra fuel into the runners of each cyl head port

u cannot use a 2.8 tb on a 3.1 since the lowe rintake has no provision for for the iac air


additionally on a 2.8 extra fuel used for startup and warmup modes come from the coldstart injector which is more of a nozzle then an injector

this injector/nozzle which ever u want to call it goes to a temputure switch mounted in the front of the intake when the temp of this sensor is cold enough it allows the injector /nozzle to stay open which then introduces extra fuel into the lower intake

on a 3.1 the ecm controls the added fuel for startup and warmup threw the 6 port injectors

 

Thanks project. This is what I came up with so far.
And one looks like a turbo

Here is the 2.8



Here's the 3.1


Please someone point out the difference.

 

I might have put the pictures on the wrong place. But other than the badge and throttle body I don't see a difference.

 

lol the turbo one is mine, i used the whole 2.8 intake on my 3.1

 

How much work and money was it to do the turbo?
Looks badass.

 

that was my rebuild, before that i ran a setup like fastedi

all the labor and materials was free form my shop.
but if i had to buy the stainless i used to build my headers it would have cost me about 1200 bucks just in header stuff..
thats why i dont build stainless headers for anyone only mild steel ones

but it cost me about the same as fast to turbo my car 7-900 bucks if u dont count the extras like a built transmission standalone ecm tq converter and suspension mods

 

Time to start saving money so I can work on it in winter to have fun in the spring and summer.

 

Been there done that. I drilled and tap'd a bigger size. I then went with stainless steel bolts. I now only tighten it down with a socket in my fingers.