Author Topic: max Hp or quarter mile time/speed (Read 7683 times)

malone · « **Reply #15 on:** April 29, 2007, 11:19:56 am »

There was a discussion about head bolts (e.g. ARP, Raceware) at tdiclub.com and a handful of owners saw headgasket leaks after only tens of thousand KMs or miles. And many of these TDIs are not big-power ones either. It could be that they neglected to inspect & re-tighten the head bolts after every xxx km, but some of them are quite experienced TDI mechanics.

They figured that the factory stretch head bolts may be better.

Try o-ringing & factory stretch bolts?? Before o-ringing & head studs.

A 1.9L TDI with 19.5:1 compression holds together just fine at ~200whp and ~350wtq with a stock head and original headbolts. I would not go lower than 18:1 in a TD as VW states that 18:1 is the optimal compression concerning performance. Don't need to deal with bigger cold start hassles at 17.5:1.

Mk2Fanatic · « **Reply #16 on:** April 29, 2007, 12:11:54 pm »

I have a complete 1.9, a 8v gasser intake and the g60 throttle body adapter flange. How much did it cost for PP to mod your 1.9 head?

Mk2Fanatic · « **Reply #17 on:** April 29, 2007, 12:13:21 pm »

never mind on prices, just read the two links.

SMOKEYDUB · « **Reply #18 on:** April 29, 2007, 01:20:40 pm »

are you going to try and gasket match the gasser manifold to the complete different design port of a 1.9?

Mk2Fanatic · « **Reply #19 on:** April 29, 2007, 02:58:19 pm »

Quote from: SMOKEYDUB

are you going to try and gasket match the gasser manifold to the complete different design port of a 1.9?

I've seen it used on 2 different 1.9 diesels - a TD and a TDI. They added a little material to make the manifold have the d shaped ports.

xud9te · « **Reply #20 on:** April 30, 2007, 10:56:16 am »

malone,

Assuming VE=1 and we have no boost, 1 bar atmospheric pressure, the cylinder pressure at TDC in an 18:1 engine would be nearer 57 BAR or 870psi before combustion.

For a 9:1 engine it would be 25 BAR or 370 psi only !!!

Simple formula to use (for ballpark figure) is take the Compression ratio and times to the power of 1.4. This will give you how may times greater the pressure is than the initial pressure in the cylinder.

However, this is the thrmodynamic theory only. Things like valve timing etc change the dynamic compresion ratio. Book states 25 - 27 bars for 18:1 for a compression check.

RabbitJockey · « **Reply #21 on:** May 01, 2007, 08:58:12 am »

has anyone tried larger studs?

Black Smokin' Diesel · « **Reply #22 on:** May 01, 2007, 09:17:32 pm »

Does the metal HG from a 1.9td help any? I'm replacing the head and I'll be using the 1.9td HG with stock headbolts and planning on at least 25psi.

SMOKEYDUB · « **Reply #23 on:** May 02, 2007, 03:11:44 pm »

i think im going for 13 mm studs this time around and i think the 1.9 steel gasket helps a bit i wouldnt go much over 25 psi if any at all.