FS-DE and FS-DET question

[E38]

Ok, new obstacle. The free engine is shot, so we have to find another. He wants to know if the 626 engine is the same? I can see that there is an FS in a 626, but is it the same one?

 

[E38]

How about that 626 engine? is it the same block?

 

[justanothermp5]

its the same motor, but there may be some differences depending on the year, I know some years of the FS in the 626 didnt have a forged crank.

 

[hornsfan10609]

Shoot for an 01 or newer FSDE block, preferably 02-03 to ensure you get a forged crank. The older 626s have slightly smaller intake manifold runners but an 01-02 626 that isn't a California car will have an intake manifold without the butterfly valves that can be an upgrade in the higher RPMs. Although deleting the VTCS and a slight port on the stock IM may be better.

 

[gato9lives]

just got done doing this swap in my car.......replace the stock motor mounts...at least the rear if you can...seems to make the biggest difference.....and can also be a pain in the a$$if done with the engine in.....you can do the inserts on the side.....also weld the lsd right now if you can...
i have a A'PEXI avc boost controller in my closet......want to install it but it seems like overkill.....any thoughts....i dont think anybody here has had one on their car...

 

[hornsfan10609]

The front and passenger side mounts have the least amount of rubber, therefore they make the biggest difference and typically fail first, but the only way to go with engine mounts is replacing all 4. How is a boost controller overkill? Assuming its an EBC and not an MBC, go for it.

 

[gato9lives]

when i replaced my mounts the sides were ok......the front one came out in 2 pieces and in the rear the bushing was worn and ripped and the mount itself was broken in 2 pieces.....when i did the rear only i noticed the engine no longer rocked back and forth. but after seeing other broken mounts i do them all as well.....
the tranny has also been known to act up...putting it in first and and shifting to second.....some bushings should help that as well....

 

[hornsfan10609]

Doing all the mouts will make shifting much much easier.

 

[E38]

Just as an update. The car is running, but here's the deal. It has a regular N/A FS-DE with the stock turbo. I've capped the boost level at about 5-6psi. Is this going to be too much for the high compression N/A pistons and rods. I have no idea of where the power is, but i know it's got to be higher than the stock FS-DET. Any guesses?

 

[E38]

He did use ARP head studs, so I know that wont be the weak point. I'm scared of what the rods will do.

 

[dmention7]

FS-DE is FS-DE is FS-DE.... all the guts are the same, whether turbo or N/A. Which is to say that you should be worried about the rods, but not at 5-6psi

 

[justanothermp5]

Yea, mazda didnt use there head on the MSP. The block and internals are IDENTICAL to a non turbo protege.
CP/ratio, rods, crank, all the same in both motors. So at 6psi, he has pretty much the same odds of blowing up as a stock MSP, which I would say is pretty high lol