Turbo Grand Prix 3500 swap

[Joseph Upson]

Good spot for the intercooler only if it will not be behind the radiator or A/C condenser. The more compact bar and plate options will likely be more efficient and maneuverable as well as easier to upgrade without having to change much else if anything.

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[Jonpro03]

[Jonpro03]

I will see how long I am going to be out of the triggers. Might be next week if TCE has some still.

Any news?

[SappySE107]

Should have some next week along with some other parts.

[Jonpro03]

For simplicity sake, I had considered putting the original LIM/UIM on the 3500. I am aware of the terrible restriction this will make. I am also pretty sure that I'll have to grind the LIM to make room for the roller rockers. You can see in the pictures I put the LG5 LIM gasket on the 3500 to see if it would seal, and it does. While I'm grinding, Ill try to match the LIM to the 3500 heads as well as I can.
I think in the short run this will be better because I'll be able to get the car back on the road quicker, which is important because my 96 is going to be sold in about 3 weeks. And I will always have the 3500 intake to swap back on when the time is right. I still have to buy a turbo!
Ideas or comments on this?

[SappySE107]

The ports wont line up if you use 3.1 manifolds on a 3500. You can't even use 3400 lower on a 3500 head.

[Jonpro03]

It does line up actually. You can see in the picture the 3.1 gasket sitting on the 3500 heads. It seems like the 3.1 had larger intake runners than the 3500!??!

However, I've decided not to go that route anyway. I'll be using 3500 LIM and 3400 UIM.

Tonight's progress:

All of the parts removed from the old 3.1. There are a handful of items that won't transfer over to the 3500 because of differences in the block.
The lower engine mount won't transfer - we will get one off of a gen3 3x00
Passenger dogbone mount won't transfer - we will get one off of a gen3 3x00
A/C compressor won't transfer due to pass. dogbone mount - gen3 3x00
Turbo oil feed line is a different size - will be heading to the hardware store
ICM and coilpack won't transfer - gen3 3x00 with wiring harness for splicing


Wont fit due to the car:
3.1 water pump will not be used - get heater core lines from 94-96 grand prix
3500 UIM won't be used - Using a 3400 UIM from u-body van to retain egr
3500 fuel rail won't be used - 2000+ 3400 fuel rail (55psi)
3500 throttle body won't be used - get 56mm TB from 3400
Throttle body cable mount will be 3100 custom for kickdown cable

Stuff that did transfer (so far)
Oil pressure adapter and Oil cooler
160* tstat
Coolant feed fitting
Driver side dogbone mount
Turbo exhaust manifolds (minus bolts... TOO RUSTY!) Im using both 3.1 and 3500 gaskets.
Alternator mount bracket / alternator

We are off to the junkyard tomorrow as I have a hefty list of things to get. That gen3 3x00 engine mount is going to be the worst.

Sorry I didn't snap any pictures. I basically have two empty motors right now and a slew of parts all over the floor.

[SappySE107]

No, the 3.1 manifolds cannot be used on 3500 heads. Install one, don't just set a gasket there and post that it can work. The 3.1 doesn't have larger intake runners. It has a taller port on the head, and the lower intake has to match that but further up the runner its no bigger than a quarter. The 3400 manifolds won't retain your old EGR. No way. They changed in 96, the first year for the 3400 van. Gen 2 is not 3x00. Those are gen 3 motors. Gen 2 is what your car had stock. Gen 1 are iron head.

[Jonpro03]

No, the 3.1 manifolds cannot be used on 3500 heads. Install one, don't just set a gasket there and post that it can work.

I didn't

It does line up actually.

The 3400 manifolds won't retain your old EGR. No way. They changed in 96, the first year for the 3400 van.

Is there no way to make this work then? I know that the minivan had a large port intake manifold that used the small port 3100 egr setup. Or would I be better off getting the EGR block plate that I bought for my LG8

Gen 2 is not 3x00. Those are gen 3 motors. Gen 2 is what your car had stock. Gen 1 are iron head.

Fixed

[SappySE107]

I have adapters for the 2000+ upper EGR style to use the old 87?-95 EGR. The 00+ uppers flow better anyway. I would not use a minivan lower either. They flow the worst of all the large ports. 2000+ are best there as well.