IP turned up.

[thx997303]

I turned up my IP today. Two flats. Yes I have a pyro, don't worry.

So, for testing purposes, I tied my wastegate shut, and ran the truck unloaded. I had to work to get it to break 9 psi of boost, and 9 was all I could squeeze out of it.

Turned the pump up, major difference. The truck feels much more powerful. Before if I floored it I could watch the tach go to 3k and anticipate the shift, now when I floor it the tach shoots to 3k and has shifted before I have even thought about it.

The turbo will push 11 psi of boost by me just flooring it, unloaded, on flat ground. Going to adjust the wastegate to limit it to about that.

The odd thing is, I expected the cruising boost to increase, but it decreased.

Before I was seeing 4-5 psi of boost and 400-600 egts holding 65 depending on the train, and now I'm seeing the same EGTs, but only about 2 psi of boost. I guess maybe I don't have to use as much throttle to keep the truck moving, meaning less fuel actually used, and so less boost created. Is that in the ball park?

The EGTs will go to 1k quicker now though, will need to make sure to watch that. That's flooring it though, I don't usually do that. And interestingly, the EGTs now drop quicker than they did before turning up the pump.

Now I'll need to re-check the timing, just to verify nothing changed, and otherwise, I think from here on I'll just use the thing. It isn't hurting for power now.

 

[wildman7798]

Very cool. I may not be far behind on this one. Trying to get caught up on little stuff and get the 3.55's and Trac Loc in before the snow. Glad to hear though, encouraging to say the least.

 

[OLDBULL8]

What is your timing set at now? Since you turned up the IP, a little more advance will give it more time to inject fuel, but gotta watch EGT close. That much boost with no load is a lot.

 

[chris142]

I'm too chicken to turn mine up!

 

[thx997303]

Well unloaded, but with the throttle slammed to the floor getting on th freeway. I wont be towing anything or hot rodding it until ive set the wastegate to limit it to 12 psi. Or 11, not sure yet. Probably 11 to be a bit conservative.

The timing was at 8.4 btdc. I intend to set it to 9.5 or so based on some threads ive read here on the subject that suggested 9.7 btdc.


As it is, i can make the egts go pretty high,but thats dependent on my right foot.

 

[thx997303]

Does anybody have any input regarding the lowered cruising boost? I'm curious why the boost went from 5 ish cruising to 2 ish.

 

[thx997303]

Well, i think ive got the answer.

Figuring a 4.11 inch bore and 4.18 inch stroke, that gives 17.1789. Then figuring WOT at 3300 rpm, divided by two, multiplied by the displacement, the engine assumed N/A, would push 2,362 cfm. At half thottle, you would push 1181 cfm, and at 1/3 throttle you would push 779 cfm.

The larger the exhaust flow, the more boost it seems. With more fuel, less throttle is needed to move the truck, meaning less exhaust to turn the turbine, and so, less boost.

 

[Agnem]

As soon as you adjust the fuel screw, you mess up the whole timing/fuel ratio setting. At 2000 RPM for example, you have X degrees of timing BTDC. But now that 2000 RPM is attainable earlier in the rotation of the throttle shaft, your timing is actually moved internally compared to where it was. This will affect your boost. You can't compensate for this with a timing meter, because the change will be present throughout the RPM range. This is why with our Moose Pumps we strongly advise NOT touching the fuel screw. The secret sauce is part of what your paying for.