Head Gasket

One for Stunned I expect

Is this Volvo set the same head gasket for the Z7U ? or is it Z7V ?
Looking in the engine manual the V will not have any ident notches where the U has one ?
http://cgi.ebay.co.uk/HEAD-GASKET-SET-V ... dZViewItem

It'll fit and work perfectly. I'd use it if it were -my- engine. Used a Volvo set on the TT DeLorean. I've had them side by side in my hands and can't tell the difference apart from the notches. I think it's an excuse for Renautl to charge you a lot more

Arent turbo gaskets thicker than atmo??????

1.46 V & X
1.70 U & W

But that's Renault engine codes for capacity not induction So Volvo may be different

And W is naturally asp and U is turbo. V is Nat, X is both. Go figure

The difference is less than a 1/4 of a mm, I can see a layer of carbon making that up.

1.46 V & X
1.70 U & W

But that's Renault engine codes for capacity not induction So Volvo may be different

The difference will make a 8.6:1 turbo engine up to 8.9:1, not taking into account if the heads have been skimmed in the past and thus even higher..

and if gaskets compress by half when in situ, it is only 1/8 th of a mm difference.

The difference will make a 8.6:1 turbo engine up to 8.9:1, not taking into account if the heads have been skimmed in the past and thus even higher..

Oh Well, Nissan RB25DET engine as in my skyline is 9:1 and will take 1.2 bar as standard.

The difference will make a 8.6:1 turbo engine up to 8.9:1, not taking into account if the heads have been skimmed in the past and thus even higher..

Oh Well, Nissan RB25DET engine as in my skyline is 9:1 and will take 1.2 bar as standard.

..with far better dynamic compression ratio, better intercooling, better fueling, better turbo and not the same engine bay heat issues..

Why do you think Renault lowered the GTA to 8:1 and then 7.6:1 in the 610....

I've asked the guy to measure the thickness Haven't had a response yet though

..with far better dynamic compression ratio, better intercooling, better fueling, better turbo and not the same engine bay heat issues..

#1 - what's "dynamic compression ratio" ?

#2 The stock intercooler is worse than a GTA one, although it has better air flow over it

#3 The stock turbo is -worse- than a GTA one. I've got them side-by side on the shelf if you want a looksee. Smaller ceramic exhaust turbine, nylon compressor. Same inlet and outlet.

#4 better fuelling? How? Bigger injectors, yes, but if you don't hit the limit, how does this make any difference to the effect of a higher/lower CR ?

#5 Likewise engine bay heat issues..... you mean they'd rather lower the CR than cool the engine better? That's fuzzy logic if you ask me.

..with far better dynamic compression ratio, better intercooling, better fueling, better turbo and not the same engine bay heat issues..

#1 - what's "dynamic compression ratio" ?

#2 The stock intercooler is worse than a GTA one, although it has better air flow over it

#3 The stock turbo is -worse- than a GTA one. I've got them side-by side on the shelf if you want a looksee. Smaller ceramic exhaust turbine, nylon compressor. Same inlet and outlet.

#4 better fuelling? How? Bigger injectors, yes, but if you don't hit the limit, how does this make any difference to the effect of a higher/lower CR ?

#5 Likewise engine bay heat issues..... you mean they'd rather lower the CR than cool the engine better? That's fuzzy logic if you ask me.

1. Static compression ratio means nothing..Dynamic compression ratio is the true compression ratio due to cam timing. The later the inlet valve closes the lower the dynamic compression ratio, the GTA has the mildest valve timing with a poor head design and 8.6:1 compression. The inlet valve closes at 40 degrees and at 10psi, the dynamic compression ratio is about 8:1 with a dynamic cranking pressure of circa 160psi. The RB25 on the other hand runs 9:1 static, but at idle and above 4000rpm runs 60 degrees valve closing timing so at 10psi runs 7.5:1 dynamic and only 145psi dynamic cranking pressure..and this is not even taking into account valve lift and head flow which on the RB will lower the dynamic even more..

..and hence why the longer duration grind cams you fit to an engine, the more you should increase the compression ratio to compensate for the loss in dynamic compression, or on the other hand, take it to your advantage when upping the boost on a highish compression turbo motor..

2. I didnt say better intercooler, I said better 'intercooling'.... the standard GTA has charge temps in the 70s on sustained boost, the Skyline doesnt..

3. Again, you can't just say a turbo is worse or better just by looking at it..., the standard GTS-T turbo is good up to 330bhp, the GTA spec T3 maxes out at 200-220bhp and then mainly turns to heat ...Ive broken two GTS-T's this year, and have enough Nissan turbo's 'on the shelf'..

4. .because the standard injectors are beyond the limit even at standard boost. The GTA runs lean top end and at peak torque as it runs near 100% duty... Skyline doesnt, it runs 370cc injectors,hence why it can go from 250-330bhp without having to upgrade fueling..

5. It all leads back to the bad charge temps, if you look at how Renault did engine bay cooling, you can see they did everything they could think of...the only way round it is to retard the timing to prevent knock (but lose power), or lower the compression and keep decent ignition timing. If you run a GTA Lemans ecu on a standard GTA 8:6.1 engine, there is more ignition advance.

So basically , all of these points lead to heat. We have a high compression ratio, both static and dynamic, which can induce premature knock, high charge temps through poor intercooling, even higher charge temps through a turbo running flat out, and a fuel system which runs lean inducing more internal heat and likely it induce knock, and engine bay temps the equivalent to a modern cooker ... so hence the reason why raising the compression ratio in any form on a GTA is NOT advisable..

Does anyone know what thickness the Volvo gasket is ?
Good to know I can cook a chicken in the bay though

[phildini]

So basically what Mr Gemtleman is saying, all you GTA turbo Owners take off your rear engine glass cover and give them all to me

Anyone fancy a BBQ GTA Burger?

[Alpineandy]

Has someone inadvertently stumbled across the secret of KFC..