60mm gds

[PToombs]

The EGT's go down when you advance the timing because it's burning in the cylinder before the exhaust valve opens, not as the valve opens. In other words, it's not burning in the manifold and turbo because it's done burning when it gets that far. It does raise cylinder pressures though. I don't think it raises cylinder temps much, it can only burn so hot in there, and then the piston pushes it out.
I know Rich doesn't want to do it, but I think he would benefit from a 1/8 timing bump. It's just a little, not a lot, and if he didn't drive it like he stole it he wouldn't have to worry about the head gasket. Yeah right!

[ellis93]

But that still means that fuel is injected sooner, right? This would mean more burn time on top of the piston, right? If so then the cylinder temps would have to increase to some degree. I would have to assume that the folks pushing the pump to the head have a lot to worry about.

[JQmile]

But that still means that fuel is injected sooner, right? This would mean more burn time on top of the piston, right? If so then the cylinder temps would have to increase to some degree. I would have to assume that the folks pushing the pump to the head have a lot to worry about.

Basically you're putting more heat into the top of the piston, and less out the exhaust. As the piston travels down, the volume increases, which means that the gases will cool...but if you have your timing later, the end of the burn time of the fuel will be later, so you'll get more leftover heat out the exhaust. You're burning the same amount of fuel either way, you're just changing where the heat is located.

Dunno if that helps, but that's the best I can explain it.

As for my experience with the compressor upgrade...it sounded badass when I had it on my 89, and it held 52psi without blowing up, but I didn't see an EGT drop. I think an intercooler makes the most sense for EGT, otherwise the factory would have gone with something else.

[Richie O]

Yup, JQ, thats what I meant to say. I am always worried about burning the tops to wax, or scuffin the walls. Advancing the timing gives a false sense of security because your pryo reads less, but the cyls are actually hotter then you think. If you are running 1500 degrees with stock timing, and advance to get them down to 12 or 1300 you are actually making more heat where you don't want it.

[ellis93]

That's pretty much what I was thinking.

I was told, in school, that heat was energy and that changing timing on any motor will determine how the motor uses it.
On a gas motor, to late of timing and your sending all your air/fuel mix and fire out the exhaust. Too early and your getting rattling and pinging which is trying to drive your intake valve back up in your head. Some motors are even more sensitive to timing, like ford 302 or 351. Even 6 degrees of advance timing, on a stock motor, will cause it to over heat buy completely heat soaking the coolant system.

[johnnyreb]

Back to the 60gds upgrade. I tow approx 10,000 pounds. Thats truck trailer and horses. I haven't touched the pump, although I do have a 3200 spring to go in and BHAf and plan to add 4" exhaust. IF I only turn my stock pin and run my fuel screw in to the stop would an upgrade show much change over the stock h1c? I also plan to install a PS intercooler and bigger cooler tubes.
It is a stick tranny, 2wd. Just rolling options around in my head. I want more power and boost without killing economy.

[bmoeller]

The EGT's go down when you advance the timing because it's burning in the cylinder before the exhaust valve opens, not as the valve opens. In other words, it's not burning in the manifold and turbo because it's done burning when it gets that far. It does raise cylinder pressures though. I don't think it raises cylinder temps much, it can only burn so hot in there, and then the piston pushes it out.
I know Rich doesn't want to do it, but I think he would benefit from a 1/8 timing bump. It's just a little, not a lot, and if he didn't drive it like he stole it he wouldn't have to worry about the head gasket. Yeah right!

I bumped the timing on my '97 from 14*, to 16.25. Lowered the EGTs 150*, dropped peak boost from 45# to 38, and improved throttle the response by a noticeable amount.

Just seems to me that the fuel being injected sooner allows more time for a slower and more complete burn and increases the power. It increased the driveability of the bigger chargers (quicker spool up) as well. Ran a PDR HX40 and later a HTT Killer B2 64/14.