What is an aceptable quench distance on a big inch nitrous motor?

What is the minimum quench would you run on a 588 cubic inch motor running two kits? The first is a plate with a 150 the second is a fogger with 300.

The motor in question:

A460 block 4.560 bore and 4.500 stroke
Bryant Billet crank
Oliver rods
Ross flat top gas ported pistons
514EX heads using ARP studs (10 bolt)
Trickflow A460 intake
Lunati solid roller...288/302 @ .050 763/763 with 114 lobe sep
Davinchi dominator

The problem:

The car runs great on the 150 plate...but when the 300 shot was tried it pressurized the system and blew off the radiator hose.

The motor has .041 copper gaskets and the heads are o-ringed.

The top end was removed and the head gaskets and heads checked and nothing was found. NGK plugs were used in the 10 heat range. The heads checked good and no evidence of failure on the gaskets.

My first thought was the tune is off but shouldn't the plugs show signs? Next was quench...pistons are .010 in the hole.

What is needed to keep this thing together? Thanks

1] 10 bolt heads
 
2] How much timing are you pullin out when the spray is on?
 
3] Compression ratio?
 
4] With bigger shots it is common to run the piston to head clearance much wider than your .051". You could move to .075"-.085" pretty quick.

Lifting the heads for sure.
Do whatever it takes for the application of nitrous to create a less violent reaction.

Lem Evans wrote:1] 10 bolt heads
 
2] How much timing are you pullin out when the spray is on?
 
3] Compression ratio?
 
4] With bigger shots it is common to run the piston to head clearance much wider than your .051". You could move to .075"-.085" pretty quick.

Compression is 14 to 1

32 degrees...5 out for the 150 and 15 more for the 300 leaving 12 degrees.

NGK 10 should be good enough.

14:1 by todays standards is certainly not in 'outerspace'. But, being that you have 10 studs rather than the 18 set up you may have to work at it harder.

I'm not at all familiar with spray and the EX-514 chamber...maybe it'll need to be 'softened' some relative to the current 87cc TFS A460 stuff.

I'm thinking a a 1/16" head gasket may be in order.

Based on what I've observed the 288* intake should be plenty in a 588" BBF engine...but...more duration on the exh. side and a wider LSA may help with the gasket issue and performance in general.

So, how big is this Davinchi dominator?

What intake manifold ?

The intake is the Trick flow TFS-54400111

I will have to find out about the size of the carb

Fuel used is C16

So you are thinking a .065 head gasket...and new cam?

We need to talk to the owner and see what he wants to do...We tried to talk him into a different cam but he wanted to use this one.

"I'm thinking a a 1/16" head gasket may be in order"
 
 
If the "customer" wants to do what he wants to do.....send him down the road.

You can change the cam around to help with cylinder pressure. That's what I would do along with a little thicker gaskets.

A little update...

We talked with Steve from Induction Solutions at the ORTC race and we are going to send the intake off and have it mapped and they are going to spec us a new cam.  We are also going to get thicker gaskets.  Hopefully the owner can gather up the money soon so we can get it going.

Ammosteve wrote:A little update...

We talked with Steve from Induction Solutions at the ORTC race and we are going to send the intake off and have it mapped and they are going to spec us a new cam.  We are also going to get thicker gaskets.  Hopefully the owner can gather up the money soon so we can get it going.

Tell Greg, he's headed in the right direction........when your spraying that much no need guess!

Ammosteve wrote:A little update...

We talked with Steve from Induction Solutions at the ORTC race and we are going to send the intake off and have it mapped and they are going to spec us a new cam.  We are also going to get thicker gaskets.  Hopefully the owner can gather up the money soon so we can get it going.

cant go wrong there.....

Are you just using o rings in the head or is the block o ring and reciever grooves in the head ?

O-rings in the heads...