Once and for all: Do TST boxes have TIMING??

[Hohn]

I hear one thing and then i hear another. Rod (@Wildcat) tells me they have timing now. Apparently they didn't before.



So is THIS the case?:

1) TST boxes originally did NOT have a timing feature.

2) They have SINCE added a timing aspect.



The reason I ask is because I have an EZ and want to upgrade to the PMAX Comp. I have been told that a piggyback is not working well lately. The added timing of the newer TST boxes with the (already aggressive) EZ timing turns out to be too much.





I figure that I could just tool around town with the DD2's and then set PMAX to KILL when I want to shred the tires,clutch, and/or VP44.



Can anyone empathize with me? I like my EZ, but I am convinced that the TST is a better fueling box for MY uses. You have to get something for putting up with the ugly packaging, right??



HOHN

 

[propuller]

Thats a great question hohn as i just ordered a new power max3 competition box & i was wondering the same thing. Anybody know for sure? kurt.

 

[Jetpilot]

I would call TST and ask them... ... 812-342-6741



Doug

 

[Rob Thomas]

I was told my Mark Chapple (from TST) that the PM box DOES have timing, upto 9*, he told me this last fall when I had my PM Comp updated. I still use the EZ stacked with it.



Later, Rob

 

[RSnaith]

Originally posted by Hohn

Rod (@Wildcat) tells me they have timing now. Apparently they didn't before.



So is THIS the case?:

1) TST boxes originally did NOT have a timing feature.

2) They have SINCE added a timing aspect.

Actually, TST boxes have done timing for many moons (I don't know if the original boxes did or not, but for the last 2 years they have), they just weren't as aggressive as many other boxes (still aren't). Its been assumed that the TST boxes didn't time because they didn't hook into the datalink, but rather time through the injector pulse.



Rod

 

[shaft]

I was also told by Mark Chapple @ TST that they did timing when I was making inquiries prior to buying my PM3 adjustable. I have also been told that they piggy back well with the EZ and know of several who are running piggy backed and speak highly of it.

 

[KLockliear]

Can someone explain this exactly? I am not 100% familiar with the TST PM box, so I need some coaching here. Does it connect to the data port or just the pump wire (as I believe)?



If just the pump wire, are you saying that it adjusts timing because the ECM sees a shorter duration between when the solenoid is released and the next upcoming pulse and therefore adjusts the timing a little to compensate, or does it really have complete control over timing to do as it wishes?

 

[HVAC]

Timing

It is my opinion that the TST box can create a small timing change by controlling the solenoid to open a tad sooner via elongated pulse width.



However, until someone can quantify the timing change the TST box is capable of, I'm of the belief it is trivial in comparison to a true timing manipulating product such as the VA or the EZ. Note TST has no stand alone timing product.



Timing control with the EZ/Comp is infinite based on intercepting the cam sensor signal and modifying that signal to the ECM.

 

[RSnaith]

Re: Timing

Originally posted by HVAC

However, until someone can quantify the timing change the TST box is capable of, I'm of the belief it is trivial in comparison to a true timing manipulating product such as the VA or the EZ. Note TST has no stand alone timing product.

I didn't ask Mark how they were accomplishing their timing advance, nor did he volunteer that information, however at part throttle loads, they are advancing up to 9 degrees. At WOT conditions, 1. 5 degrees. I don't know the inner workings of the VP44, but I suspect thats more timing advance than you can get by simply elongating pulse width.



Someone correct me if I'm wrong, but I thought that fueling wire that we're hooking into could control pulse start and stop, and thats how the pulse was elongated in the first place.



Rod

 

[robertyoke]

this is my 2 cents and how i understand it. mark explained it to me that the cummins computer retards timing at more than 1/2 throttle. so if the powermax adds fuel you dont have put your foot in it you get timing advance but if you floor it no more advance and egt's go through the roof. i know that last part all to well i have seen the gauge go past 1600 degrees many times.

 

[HVAC]

Timing Advance

If Mark is getting 9* of timing out of the PM then I'd say that's impressive. I'll tip my hat to them.



But wouldn't you want that advance on the top end rather then elsewhere? I don't know the timing curve of other products so I'm not saying TST is different.

 

[KLockliear]

Re: Timing

Originally posted by HVAC

It is my opinion that the TST box can create a small timing change by controlling the solenoid to open a tad sooner via elongated pulse width.

This would require knowing cam or crank position to determine WHEN to start the injection, would it not? Without that input, you can only hold it open longer, not start it sooner.

 

[Marco]

No timing.

Take out a scope and watch the signal from any of the major fuelling boxes on the pump wire. What they do is to add a SECOND injection stroke AFTER the "main"stroke send from the ECM.



In no way can you open the VP fuel solenoid sooner than the ECM tells the VP to. You get a check engine light and loss of the syncronism trigger between the ECM and the VP. The engine stalls and eventually dies.



Hmmm, just to end, NINE degrees advance????

Way to much! Harms the performance!



Marco

 

[RSnaith]

Re: No timing.

Originally posted by Marco

Hmmm, just to end, NINE degrees advance????

Way to much! Harms the performance!

That appears to be the subject of controversy, and at full fueling and high RPM, I agree. It would kill performance. This is why the boxes (at least the Edge and TST products) reduce timing based on throttle position and RPM (more throttle postion = less advance). We're also talking pump timing. That does not necessarily equate to mechanical timing.

 

[Marco]

I'd suggest to learn more about the principles of the VP.

The TIMING is varied in the VP rotating the whole injection head.



While the fuel solenoid opens when the plungers of the VP are on the rising side of the so often mentioned donut.



If you'd open the fuel solenoid sooner then the VP would do ( If it could be done without causing other problems) well there would be no pressure to inject the fuel.



To make it short, the timing can't be varied through the fuel solenoid valve. The timing in the VP comes from a different part of the pump.

 

[RSnaith]

Originally posted by Marco

To make it short, the timing can't be varied through the fuel solenoid valve. The timing in the VP comes from a different part of the pump.

I actually wasn't debating your response about the solenoid, Marco, just your comment about 9 degrees being too much advance at part throttle loads.

 

[Marco]

How can you say that 9° are not too much???



Marco

 

[RSnaith]

Originally posted by Marco

How can you say that 9° are not too much???

My understanding of the 5. 9 system is that 9 degrees of advance at the outlet of the VP44 does not mean 9 degrees advance in the combustion chamber. Or is this incorrect?

 

[Marco]

I'm not sure if I understand your question correctly.



If we advance the timing by 9°@ 1000 Rpm we get a 9° advance in the combustion chamber. If we use the same value for advancing the timing at 2000 Rpm then we get less advance caused by the injection delay (remains the same over the whole Rpm band) but the piston(s) are faster.



That's why I don't understand your question, we're talking about the VP or the P pumps?

The VP can be adjusted (and is) dinamically to the RPM's of the engine. The ECM does that math.



For the P pump the story is obviously different. There's only a static timing... .



Marco

 

[RustyJC]

Partial load timing advance for improved efficiency is nothing new. Does anyone remember vacuum advance distributors on gassers?



The whole idea behind full load retard and part load advance is to keep the peak pressure angle (i. e. , the angle of crankshaft rotation at which peak pressure occurs) more or less constant for optimum efficiency across the torque (BMEP) range of the engine. Having said this, sometimes it is necessary to compromise the optimum peak pressure angle in order to control peak firing pressures - see next paragraph.



Secondarily, full load retard keeps peak firing pressures in check - it also raises EGT's and provides more drive energy to the turbocharger. At partial load, peak firing pressures at the same timing setting would be lower, so there's room to advance the timing without exceeding maximum allowable peak firing pressures. Advancing the partial load timing (up to a point) allows more energy to be extracted in the cylinder and less to be dumped into the exhaust since less turbocharger drive energy is required at partial load - thus, improved brake specific fuel consumption, improved response, etc. Retarded timing at partial loads is, however, beneficial in reducing peak combustion temperatures and, therefore, NOx formation - probably the critical factor in factory partial load injection timing settings.



Rusty