Effects of a Thicker Metal Head Gasket on N/A 7M

[Drewisweird]

Now before I get flamed for asking this here is my situation. I have a N/A MK III that I would like to eventually convert to a turbo engine. My issue is I have to pull the head now and change my head gasket to get the car running, I'm tight on cash, and I'd like to only have to do the job once.

What I was wondering is if I did all the prep work for a turbo engine while getting the engine running properly again (Head machined flat, Thick Metal head gasket, ARP studs) but not put the turbo on just yet would I still be able to drive the car? Obviously I would have a lower compression ratio but would I be causing any harm or potential damage to my engine or would I just be slightly down on power due to the lower compression?

Sorry if this has been answered before, I have been searching through the forum and other forums with no luck to answer the question so I'm hoping someone can help me out here.

 

[hvyman]

Would just not have as much power.

Also best to machine both the head and block when using a mhg.

 

[Drewisweird]

Do you know what the power drop would be?

 

[hvyman]

There is no way to tell.

 

[Rollus]

http://www.wallaceracing.com/hp-cr-chg.php

 

[Nick M]

The machine shop should be able to tell you the new combustion chamber CC. Also, if the gasket is thick enough you will alter the engine timing very slightly. Not so bad that you are off a tooth, but it won't be "straight up".

 

[Rollus]

You can try and play with this: https://docs.google.com/spreadsheets/d/1iMzErRr5pl7mRbzreY4t3QuiO8mRGWlfrucfxyqjRBc/edit?usp=sharing

Actually, if you use high octane content fuel, N/A CR won't hurt.
C/R is 8.4 for turbos and 9.1 for N/A.

I choose to have a 9.5:1 C/R for my turbo build...

 

[Faye]

True, you can use the MHG but you won't just be pulling the head, you have to machine the block also, so you'll be putting in a lot more work. I'm building my 7M on a budget and have the "do it once do it right" mentality also. I think that it will end up costing more than you think to do the whole job if you actually go the MHG route now. At least in my mind I was thinking that well, if the head is off and at the machine shop then I want to also get valve guides and seals replaced, and since the block has to be stripped down anyways to get hot ranked and decked I may as well replace all my bearings and bolts as well, along with all related seals, etc. ... Plus oil pump.... I dunno may be cheaper for you in the long run to go stock and keep going for now then pull the motor for all the work when you're ready to go turbo..... You also never know what you're gonna find when it's apart anyways, or what you might break haha.


IG: tougefaye

 

[Faye]

Oops edit: Tanked not ranked lol and hvyman beat me to it, sorry missed that post....:/


IG: tougefaye

 

[Nick M]

I choose to have a 9.5:1 C/R for my turbo build...

Good choice.

 

[Rollus]

Thanks, BTW I should explain my choice better, because the higher cannot always be the best

In France we have 95-E10 and 98 octane, I think they are premium fuel. With 3p, we actually find EUDM Ecu have little different maps, and conclude it was due to fuel

With good timing I will be pretty safe on SP98, in case I need this fuel (see after). I should'nt use SP95 or SP95-E10.
I will mainly use E85. If I wouldn't be safe with pump fuel, I would choose higher C/R to achieve 18+ dynamic compression ratio under boost. E85 would enjoy that.