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Discussion Starter · #1 ·
I had some free time today and decided to do some research. I've come up with the following:

4G69 uses 4G63 rod and crank bearings (old news)
4G69 uses 4G64, 4G94 valve guides and seals
4G69 uses the EVO timing belt tensioner which is aluminum, not cast iron
4G69 intake valve = 34mm (4G63 EVO = 34mm) May fit?
4G69 exhaust valve = 30.55mm (4G63 EVO = 30.5mm) May fit?
4G69 uses 4G64, 4G94 valve spring retainers
4G69 uses 4G63, 4G64 head bolts (can use 4G63 ARP head studs )
4G69 uses 4G63, 4G64 main bolts (can use 4G63 ARP main studs )
4G69 uses 4G63 EVO balance shafts (can use 4G63 EVO BS eliminator kit )
 

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Discussion Starter · #3 · (Edited)
yeah no prob. The intake and exhaust valve springs in the 4G69 are unique to that engine and don't cross reference with any other engines. The internals are very strong and can handle 10-15psi of boost on stock internals, I believe. And I also found out that the 4G69 is that the block height is 6mm shorter than the 4G64. This brings the block height back to the same as the EVO 4G63. The 4G69 uses the same length rods as the EVO with a longer stroke of 100mm. EVO pistons, even forged ones can be used in the 4G69. However, these pistons need to be 87mm. That's the only downside. The solution is to get stroker pistons for the EVO in 87mm. 87mm pistons for an EVO, however, are not easily sourced. They more than likely would have to be made custom by JE, Wiseco, Arias, etc.
 

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Aviator
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yeah, ive heard that about our stock internals. I love mitsu engines. this is all great information, good to know stuff. I noticed the GT guys have similar threads in their respective forums. Thanx for doing this research. e-rep to ya.
 

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OldNut
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NO, 4g63 valvetrain parts wont switch over to the 4g69 :(

i have researched this a lot and have come to the conclusion that custom made valve springs is the way to go
 

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Hey so everyone has been saying that the 4g69 can only do 8 psi max. maybe 9 with a good tune. If this thread is saying that the motor can hold up to 15 psi? How come everyone is stopping at 8? And if I can do up to 15 psi, what needs to be done to achieve that?
 

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It depends on the turbo and tune... but we have seen 8 be a consistently safe number. In terms of eclipses max we have seen is 10.. but the ralliart lancer guys have gone higher.

So I still say stay at 8 if you want to be safe.. and with a good tune you can consider risking 9..
 

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ahhh 10 psi killed a eclipse already.... 8psi is safe on a car with a stock engine, bullet proof the engine and you can go higher boost.
 

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The Dark Side
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^and with the cast iron block the engine is pretty sturdy
 

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Theta II
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Ok so Mecks is running 10 psi and has not killed his car. It has nothing to do with the AMOUNT of BOOST you are pushing it has everything to do with the CFM"S. It depends on the Turbo you go with. Our springs are fine with piston's and rods upgraded you will be good for about 500hp if you ever make it there. Other than pistons and or rods the only other that has given up under duress was the crank at about 675 hp. There are plenty of threads with this information on here SEARCH!!!!!
 

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I've been told by rre with pistons we can do 10-12.
Based on the results of Whynott's turbo I would say be sure to upgrade rods aswell before upping boost beyond 8-10
 
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