2g head in a 1g?

[spidy3]

Head has a stage 3 P&P job, upgraded springs and valves. So only thing that needs to be done is the head bolt holes? is it possible to use 2g head studs or are the threads different for the blocks?

btw the head is off of a 96 GS-T

thanks

 

[spidy3]

Will a 2g head work without any modifications on a 6bolt 1g block?

I have a 91 TSi and my friend is selling his head off of his 2g. I want to know if it is a direct bolt on.


Dom

 

[wolf20043]

Will a 2g head work without any modifications on a 6bolt 1g block?

I have a 91 TSi and my friend is selling his head off of his 2g. I want to know if it is a direct bolt on.


Dom

It could work, but the intake ports on the 2g head are smaller than the 1g, so air going into the head will not flow smoothly unless you were to port the 2g ports to the size of the 1g. You would be better off finding a 1g head.
Mike

 

[fsu99gsx]

Yes the head would work. It is not a direct bolt on though. You would need to get the head bolt holes machined out to fit the 1g head bolts and like the guy before me said you would probably want to ge some porting done.

 

[jwaked]

Yes the head would work. It is not a direct bolt on though. You would need to get the head bolt holes machined out to fit the 1g head bolts and like the guy before me said you would probably want to ge some porting done.

What he said.

 

[AUSVR4]

Would the need for porting be eliminated if he used a 2G intake plenum? Or do i have it wrong?

 

[u12run]

It could work, but the intake ports on the 2g head are smaller than the 1g, so air going into the head will not flow smoothly unless you were to port the 2g ports to the size of the 1g. You would be better off finding a 1g head.
Mike

+1 The 1g head flow way better then the 2g

 

[fsu99gsx]

It's not that you need to port it, but you would lose power if you did not. And I would still use the 1g intake with it even without porting. On a 2g it is considered an upgrade to switch to the 1g intake, even without porting although porting makes a huge difference.

 

[ericbev]

The size of the ports isnt everything guys. There is alot more to it. Jim knows his stuff. Figured id post what he said instead of linking.

What sort of scientific proof has "look at it" been turned into? What makes you think that you will gain HP with a 1G head over a 2G head just because the intake runners are larger?

The larger runners on a 1G head have a much larger angle into the valve, this actually slows the air entering the cylinder chambers. Generally on a port job of a normal head for racing they raise the chambers not lower them so the entry into the valve is a straight as possible. The angle into a 1G head is horrible because the port is so low already in the head.

The HP increase from a 2g head to a 1g head is from the Cams, and Intake manifold. If your using aftermarket cams and plan on buying a SMIM don't put on a 1g head because you'll end up with no gain and a head that has horrible port design.

Most major racers now using DSM's are using a 2G head and 2g style intake manifold and raising the runners in V8 styles so the air is hitting the top of the valve as straight on as possible. Air flow has nothing to do with the size of the chamber and EVERYTHING to do with the shape and design.

Putting a 1g head on a 2g block is the OPPOSITE of what you want to do. Replace your 2g block with a 1g block and keep your 2g head. Have it ported and port raised and add a set of HKS or Comp cams with a SMIM. This will provide you with a much more potent street engine.

Also AMS Eric 2.

Use the 2g head!! The castings on 2g heads are far superior to 1g castings. They have more alluminum in the lifter bulkhead to reduce flexing and less problems with casting shifts than 1g heads. The intake ports are smaller yes, but they do not seem to be a restriction of any sort. The Evo 8 heads have the exact same intake ports and we are making 600+ whp constantly on completly stock unported ones. Our shop car's intake ports arent opened up that much at all and it makes over 800 awhp.

Use the 2g head, drill the head bolt holes out to fit the larger 12mm studs, find yourself an Evo 3 intake manifold, and you'll have the same top end package as an Evo 8, which has been proven to consistantly outperform 1gs. It will save you money, make your swap far easier and WILL outperform a swap with a 1g head/intake, much to everyones dismay.

There are alot of threads about this. Search away and start sifting.

 

[allgripnoslip]

Smart words right there