Outer Limits 4x4 Board

i heard u can put a gti head on the vit motor does it make it go much better do u use the manafold of the 1.6 any help would be great cheers matty

If you use a GTI head on an 8V carby motor you'll create an interference motor, but it will OK, so long as you can tune it for the larger capacity/lower compression and deal with firewall clearance.

However, a 16V SOHC vitara head flows better than a GTI head, already has a right angle distributor drive, and is a free spinner on it's matching block, and is already tuned right.

Steve.

Has someone actually done a flow test on a GTI vs 1.6 head? What were the results?

What makes the 4v flow less than the 2v?

Thanks

Mike_1324 wrote:Has someone actually done a flow test on a GTI vs 1.6 head? What were the results?

What makes the 4v flow less than the 2v?

Thanks

Yes, and the comparison we are talking about here is between the dohc 16v Swift head and the sohc 16v Vit (MPFI) head, not the sohc 8v Vit head. The Vit head outflowed the GTi head BUT if you were to do some "serious" port work then the GTi head does work better in the end but we are talking for a pretty serious motor with cams etc. I cannot remember the exact figures now but they came from someone building G Series engines for motorsport and he could use what ever he wanted and all the testing showed that the G16B head worked better unless the porting on the GTi head got pretty serious and then bottom end went out the window.

Mike_1324 wrote:Has someone actually done a flow test on a GTI vs 1.6 head? What were the results?

What makes the 4v flow less than the 2v?

Thanks

www.redlinegti.com is your friend.

GRPABT1 wrote:

Mike_1324 wrote:Has someone actually done a flow test on a GTI vs 1.6 head? What were the results?

What makes the 4v flow less than the 2v?

Thanks

www.redlinegti.com is your friend.

Nah i have a mate with a propper flow bench.

I was just wondering why everyone thought that the 4v would flow lees than the 2v, but its not, its 4v vs 4v 1.3 vs 1.6.

All sorted

Ta

.

All I know is that a mate has done this conversion, it goes really well and sounds awesome at big revs in the mud

The GTI head may not flow more and therefore not be any better on paper but in the real world it did make a difference.

larger ports does not always mean more power.
at low revs a smaller port will out perform the bigger port, but will limit the power at high revs (by restriction). it is all to do with air velocity.
the shape also makes a huge difference.

also the g13b head is better to tune, cos you can alter the cam timing seperatley, and has the capacity to be enlarged if you so wish. also no rockers means less power losses in the valve train.

but you can also argue that there is more rotating mass, cannot adjust the valve clearances (easily), is possibly heavier?, whatever.

Toecutta wrote: The GTI head may not flow more and therefore not be any better on paper but in the real world it did make a difference.

Was this compared to a G16 SOHC head on the same engine? Bear in mind the G13B GTi engine will have more aggressive cams in it than the G16, and make more outright power, but all up, when fitting the thing is taken into account, it seems the G16B sohc 16V head is a better option for a sierra.

Steve.

i was thinking about putting one on my g16b im after more power for offroad racing