3400/3500 top end swap on a 2.8

[3100 MPFI]

I usually mix those up.

Lorenzo was telling me to get the 3500 intake for my 3100. He says it will help all around in the powerband, but then again, my 3100 never performed in the way we expected it too.

[Tonglebeak]

3100, I'll be taking the pics tomorrow. I'm in the process of getting a 3400 plenum off ebay (I'm going conservative for my first time doing engine work) and all I need know are heads.

What about a throttle body? 3400 throttle body or will a 3500 tb bolt up the same way? Are there different sizes (Obviously I want the biggest one lol)?

[3100 MPFI]

You will want either a 3100, or 3400 throttle body.

You can't use the 3500 throttle body. It is mounted totally different, and is not a cable driven one. The 3500 throttle body will only mount to a 3500 intake.

There are 2 sizes to the 3100. 52mm, and 56mm. All 3400's are 56mm.

[Tonglebeak]

What about the 62 and 65mm throttle bodies that I see for sale on the store? Will they actually show any gains?

[3100 MPFI]

If you do some work to the exhast, then yes, you will see some gains.

You can use one of those, or if you want to save some money, and get it later, then you will need the 3100/3400 throttle body.

[Tonglebeak]

I took some pictures today, not sure if it's what you needed though: also, will my stock injectors be fine?

http://img512.imageshack.us/img512/9444/dscn0764ps8.jpg

http://img123.imageshack.us/img123/3451/dscn0765rc4.jpg

http://img441.imageshack.us/img441/5525/dscn0766de9.jpg

http://img441.imageshack.us/img441/4003/dscn0767qc9.jpg

http://img123.imageshack.us/img123/4057/dscn0768ox3.jpg

http://img123.imageshack.us/img123/5191/dscn0769pf8.jpg

http://img49.imageshack.us/img49/8928/dscn0770cs6.jpg

http://img134.imageshack.us/img134/6562/dscn0771eq2.jpg

[3100 MPFI]

Looks like you can probably do the cam in the car. Looks like you have enough room.

[Tonglebeak]

Cool. Will my stock injectors work for this? Also, I'm assuming this is the throttle body I need? Will the linkage from my old tb work for this?

http://cgi.ebay.com/ebaymotors/GM-EGR-Valve-99-05-3-4-V-6-3400-Throttle-Body_W0QQcmdZViewItemQQcategoryZ33607QQihZ003QQitemZ130163554895QQrdZ1QQsspagenameZWD1V

[3100 MPFI]

throttle body yes, rest of it, not really.

No, you can't use your current linkage. They are totally different. You can get a cheap junkyard one from a Ciera, and swap out the linkage you need.

You will want to most likely use 3100 injectors. Not really sure of that part of it. I think the 3100 will be best, but since it is going to be a 2.8 block, I really don't know in this case.

Sending a PM now.

[86euro]

Hey Tongle, the throttle body is what will give you some issues for your linkage. A 3100 ciera uses an odd-ball linkage on an odd-ball TB that has a built in MAF sensor. I think the 3100 ciera TB will bolt to the upper intake from other cars, but I'm not sure. You would need to use the matching throttle cable that has some sort of reduction/reverse action box included with it. That TB shouldn't be too restrictive on a 2.8, but it would still be lacking a provision for the TV cable of the 3speed. I think it would make more sense to figure out something to use with the 3400 TB, because if you're going to have to adapt, you may as well adapt a better part.

You need to go to the junk yard and rob a 3100 ciera of several parts. You will need to get all the heater hoses, fittings, fuel rails and anything else that looks different. It will make things easier when you are swapping the parts. I don't know why the 3100 ciera used the side dump rear exhaust manifold, but I would stay away from it. There is much more clearance for the center dump style.

[IsaacHayes]

The 3500 plenum has no runners but instead tons more plenum volume. Also the TB neck extends down and opens up in the center, giving equal flow to all ports. It helps on the high end and also on the low end some too. I noticed that the sudden power at 3,000rpm no longer hits like it used to, like it evened out the power more. But that may be because I went to large port lower too. I never had a 3400/3100 large port upper on to compare.

If you want a TB that has a reverse linkage thing to pull a cable, one from a 3100 1994 would work, (looks just like inverse part where the pedal connects). Later ones up till about 98 used the same setup but the part I'm talking about on the later ones didn't have a channel for the cable but still had a hole to attach somehow. You could use that for the TV cable.

Here are some pictures of my 1994 linkage.

[Tonglebeak]

Just to be clear, you _are_ saying that the '94 linkage can be put on a 3400 throttle body, correct?

[3100 MPFI]

yup. All linkages from any 3100 or 3400 can be swapped out fairly easily.

[Tonglebeak]

Got the LIM and exhaust manifolds today.

I notice the hybrid guide says something about a MAP-Plenum-FPR hose. WTF is that?

[3100 MPFI]

It is the small hose that goes from the FUEL PRESSURE REGULATOR across the top of the engine to the MAP sensor on the back of it next to the ignition coils. The vacuum lines pulgs into the plenum right under the MAP sensor.