VL NA converted Turbo head gasket thickness advice

[HsvR86.2]

Hi All,
Have a VL NA converted to Turbo, after a thicker head gasket, looking into MLS cometic
.
They come in 1.29mm. 1.89mm and above 2.0mm thickness.

Planning to run hi boost (20psi) any advice would be great.
2.5mm thickness would drop it to nearly 8:4:1 or something like that?

Seems like 1.29mm is default choice for rebuilds?

Leaning towards 1.89mm thickness. What thickness do people mostly use?

Will keep it on 98 octane for now but will eventually go on E85.

TIA

 

[HsvR86.2]

Anyone surely? TIA

 

[Deuce]

If you can drop compression to the 8's or low 9's that's what I would go for.
Probably the low 9's if it was me

 

[HsvR86.2]

It's already low 9s, Vl turbo are 7:8

 

[Pollushon]

It's a balancing act. At those pounds a thicker gasket is more likely to let some gas out and lose reliability full song. Compression ratio is moot if it leaks. I wouldn't go much higher than 1.60 in your shoes, so 1.89 realistically, I assume she's using studs?

 

[HsvR86.2]

It's a balancing act. At those pounds a thicker gasket is more likely to let some gas out and lose reliability full song. Compression ratio is moot if it leaks. I wouldn't go much higher than 1.60 in your shoes, so 1.89 realistically, I assume she's using studs?

Thicker the gasket more prone to leak at high rpm? In that case I might go with 1.29mm as I am not using head studs...

 

[Pollushon]

More prone to leak at high boost, 20 pounds is a big bang that needs studs no matter what the gasket

 

[HsvR86.2]

Update, changing paths and now going with Nitto 1.1mm with (fire rings) head gasket as opposed to mls cometic 1.29mm gasket.

apparently nitto seals better and have stronger fire rings.
cometic is good but would require copper spray and wet stone/knife sharpening the block as cometic are very sensitive and my leak compression if not done properly.

 

[Pollushon]

Pretty sure the Nitto is MLS too, another must for big boost

 

[HsvR86.2]

Pretty sure the Nitto is MLS too, another must for big boost

Correct, but different material between the two, cometic is 100% steel whereas nitro has a bit of rubberish to it.