torque plates

[SRehberg]

This is going to be a really dumb question, but I keep seeing everyone talk about different plate numbers or at least sliding the stock one forward. I haven't a clue as to what you are talking about, so take mercy on a less than knowledgeable Cummins owner. Is this a good thing to alter or are there trade-offs to be careful of, especially when going to something other than the stock plate adjustment?



_________________



'96 2wd auto, bone stock pulling a fiver 27'

 

[drawson]

SRehberg,



First off you should get gauges before doing any moving of the torque plate. I would suggest getting a TST plate over moving the stock one forward. There are instruction on this web site http://www.tstproducts.com/



The old saying goes something like this "DC made our trucks TST make them run!!"



One last thing be careful starting this bombing run it is adictive.

 

[Joe G.]

Actually, it's pretty simple. The torque plate is the throttle stop. Think of a piece of wood under your loud pedal. The thinner the piece of wood the more throttle you have. It's the same thing with a torque plate. ALMOST! The throttle position at WOT (Wide Open Throttle) is determined by a "feeler" piece of metal that contacts the torque plate. Where the complication comes in is that the feeler contacts the torque plate at different places depending on the RPM at WOT. Thus the torque plates have a shape ground into them. Since the feeler comes from the rear to contact the plate you can achieve more fuel at WOT by just moving the stock plate forward in it's adjustment slots. However, the stock plate shape is not all that good for operation in that position because of Exhaust Gas Temp (EGT) problems. So before messing with it, you really need an EGT gauge. To go along with a torque plate you need to increase boost so you have more air to help burn the additional fuel available. The TST power kit comes with a replacement elbow for the hose to the wastegate. The normal maximum boost before the wastegate opens in 18 PSI. With the replacement elbow which is partially blocked off with a set screw the boost may be increase to 28 PSI or more. Check out the TST web site for installation instructions so this little explanation makes more sense and a chart of the available plates. Note that the different plates are rated differently depending on the pump you start with. TST is here:



http://www.tstproducts.com/

 

[400Magnum]

I think I get it now!

Joe G. ,



As a relative newbie to the Cummins world, I'd just like to say "Thanks!" for explaining how the torque plate works. I've been trying to figure it out from the pictures and descriptions of the different plates and mfg's different websites, but none really explained HOW it worked. I could never understand how something that changed power output so dramatically could also be relatively streetable too, and not affect fuel mileage much. That is, it wouldn't affect fuel mileage as long as you can resist the urge to not use the new-found power.



I think I'm beginning to understand things now...



So, if a person switches to a new plate, and as long as they drive in a normal manner, the feeler that you talk about will stay on that section of the plate where the fuel rate would probably be pretty similar to the stock plate. But when the throttle pedal gets mashed, the feeler moves to a different section of the plate that has a different contour than the stock plate, and it's been changed to allow additional fuel to be fed to the engine. Along with that, the new elbow causes the wastegate to bleed off slower, so that more boost is created. More boost means more air to go with the increase in fuel. Am I getting this right???



Thanks for the information, I'm starting to make sense of things now, I think...

 

[Bseg]

I noticed a disclaimer that the TST plate can't be used on '96/'97 with the EGR valve. I assume this is just a CYA for TST but with regards to that, if you decide to add the plate to one with the EGR valve isn't recommended to remove the EGR valve, install a blockoff plate, and use the non-EGR intake? What would be the safest amount of H. P. to increase with a stock auto trani?



Thanks.

 

[Joe G.]

400Magnum,



The position on the torque plate curve is determined by RPM. Think of it as a throttle stop that varies the amount of fuel at WOT according to RPM.



Bseg,



I'm not really sure about the EGR valve business (I have a '95 ) but I would think that if the EGR is blocked off it would be very similar to a non-EGR model of the same year and transmission.



The DMV would probably give birth to a fuzzy worm if they found it blocked off, but I haven't heard of anybody being checked for that.

 

[HoleshotHolset]

Does anyone have insight on the introduction of an inert gas into the diesel combustion process. . ?

EGR does exactly that... . it introduces gases that are the result of internal combustion... . and in effect cools the EGT on gassers. This was a bit of a band-aid fix for the higher compression engines and lack of leaded fuel to reduce precombustion (That 70's Show era... . ).



I figured that if we were not putting any more fuel into the process... . how could EGT's soar when everyone always says: "more airflow leads to lower EGT's (assuming fueling remains unchanged)... . "



Maybe it's the heat from the exhaust that the EGR adds..... putting hot air into an engine is a surefire way to increase EGT's.



I'm very curious...



Matt

 

[400Magnum]

Joe G. ,



Right, I got it now, Thanks! I was never making the connection that the rpm had anything to do with it. I was thinking that it was strictly related to throttle position or something like that. I guess I'm still stuck in "gasser" mode, thinking along the lines of a throttle body or carburetor. But I'm understanding it better now.



A little knowledge is a dangerous thing...



So, back to the original question, when the stock plate is moved forward, the entire rpm range/throttle range is getting extra fuel added to it, and this is why a person needs to watch the EGT, right?



If the boost doesn't get increased to take advantage of the extra fuel being added to the mix by moving the plate forward, it won't add much extra power will it? It would only add power up to the point of using up any excess oxygen that was present, then after that it's just wasted.



Am I still on the right track?

 

[Brandon]

egr air horn very restrictive... ..... need to talk to californians in the know... ... ... ... ... .

 

[Joe G.]

400Magnum,



Pretty close. In a gasser when you mash the gas you open a butterfly valve that increases the amount of air to the fuel system. A carburator or fuel injection then provides the amount of fuel to maintain the proper fuel air mixture.



Not so in a diesel. No butterfly so the air system is wide open all the time and the cylinder gets a full load of air every time. The injector system provides the amount of fuel required to do the work. Note that "proper fuel air mixture" does not apply since you can be a lean as you want and it runs fine. At some point you dump more fuel in than you have air to burn cleanly. The result is lots of smoke. To get around this we use a turbcharger. The more boost the more air stuffed into the cylinder so you can burn more fuel cleanly. This is the reason that when you jump on it at low boost the rice burners tailgating you have a vision problem. Just adding more air won't increase the power you can make if you are already running enuff air to do the job. If you mess with the trottle stop to get more fuel you need more air. You can overdo all this and really get a good fire going (burn holes in pistons!) if you are not careful, thus the need for an EGT gauge. A boost gauge is helpful too. For one thing, if your boost goes away you want to take care of the problem. Hard to tell without a boost gauge. There are differences of opinion about how much air is enuff, but the above is the general idea.

 

[JohnE]

changing the subject slightly

<blockquote>400Magnum uses

... Royal Purple 10W-30</blockquote>

400Magnum

What's your impression of Royal Purple?

I'm changing to a popular 5W-30 synthetic for the winter and plan to use the 15W-40 for the summer.

Do you use the 10W-30 year around?



-John

 

[JohnE]

Piers of <b>P</b>iers <b>D</b>iesel <b>R</b>esearch (<a href=http://www.piersdiesel.com/ target=_blank>PDR </a>) fame posted some good cut away photos on his website of the beloved P7100 injection pump. The photos under &quot;Technical Info&quot; show the interaction between the governor lever and the (fuel) cam plate.



Piers is a great source for information and for purchasing a TST plate at a great price, too.



-John

<font size=1>I am not affiliated with PDR.

I also cannot get my &lt;html&gt; correct.

My spelling is horrorable, to. </font>

 

[ablakemore]

TST kit with EGR

I would be interested in anyone that has installed a TST plate on a truck with a EGR fitted California truck. What kind of problems and how you installed it etc. I have one of those and my next upgrades were going to be a TST plate and Exhaust brake.





1996 CTD, 5 sp, 4x4, 4:10



Thanks

Allen

 

[SRehberg]

Thanks for the replies on the torque plate; I had no idea how it worked nor that it would generate this lively of a discussion. This is a great forum for information and I thank everyone for the input. The one thing that slows me down, is the fusible link in the drive train, commonly known as the automatic trans. Can they take it much more than stock?





________________________



'96 2wd w/o EGR and toying with the torque plate idea.

 

[Joe G.]

Ask Bill K. that one

Yep, and here is where you find out about it:



http://www.dieseltrans.com/DTTech/index.sht

 

[HoleshotHolset]

O. K. , that makes sense.

If the EGR is placing a restriction in the intake airflow into the engine... then I can see a huge problem. That's unfortunate... .



Matt

 

[GMIKEP]

Re. OEM Torque Plate Slid Forward

Just another data point. Prior to installing a TST #6 plate, last weekend, I took my stock plate and slid it "all" the way forward (did not increase slot lgt. ) as well as the AFC forward, 20 clicks in on the AFC starwheel. Checked adjustment on cam contour follower so it did not ride under plate. Also blocked off the turbo wastegate. I will use this as a baseline to the #6 plate performance.

Seat of the pants indicates off line response is much better, turbo spoolup comes on almost immediately, very little smoke, max. boost now hits 28 -30psig (vs 18 stock psig max) and EGT now max's @ 1250 (vs 950 stock). Govenor still stock, so defuel takes place at ~2700RPM. Mid range torque is greatly increased. Bottom line - vast improvement stock!!



1995 2500, std. cab, auto, bone stock, correct gages. 110K miles

 

[Joe G.]

Mike,



I have the same truck you have except it's a club cab. I also had those same numbers with the stock plate slid forward. One thing I noticed with that set up is that I always got close to the EGT limit pulling my 32' TT up a long steep grade and had to lift. I have lots more power now (see sig, hauls butt!!!) and I'm not seeing those EGT numbers in the same situation. It still gets hot, but not as hot as it was.

 

[GMIKEP]

Re: Torque Plate

Gotcha Joe,

As I don't have a load to tow (right now), I don't know the max EGT I'm capable of with this setup, but seeing the way EGT climbs with WOT B/4 defuel, I would be in trouble if I had to produce any more HP.

Waiting on Bill K's VB to arrive today. If I get it in this weekend I will install the #6 next week. Then the TC next month. Will post progress.

 

[JohnE]

<blockquote><font size=1>Holeshot said:

Does anyone have insight on the introduction of an inert gas into the diesel combustion process. . ?

EGR does exactly that... . it introduces gases that are the result of internal combustion... . and in effect cools the EGT on gassers. This was a bit of a band-aid fix for the higher compression engines and lack of leaded fuel to reduce precombustion (That 70's Show era... . ). </font></blockquote>

HSH

I tried to reply to your question last night, but I didn't have the mental fortitude to give a good answer so I deleted it.



<b>E</b>xhaust <b>G</b>as <b>R</b>ecirculation or EGR adds de-oxygenated gas to the intake. It is essentially the reverse of using nitrous. Internally, it functions the same for spark ignition or compression ignition engines. De-oxygenating the intake air slows the flame front. Slowing the flame reduces peak combustion temps and pressures. Peak combustion temps and/or pressures produce higher NO^x levels.



High octane (90-99) and high performance number (100+) gasoline burns slower. The higher the number the slower it burns. This is required for high compression or extremely lean running engines. It does not reduce significantly NO^x levels as higher compression especially combined with lean already makes those numbers sky rocket.



Knock is really over efficient combustion. The flame moves very quickly which produces the audible <b>knock</b> Oddly, many people found this out when they removed or disabled the EGR on their gas engine.



I don't know how Cummins put EGR on the California 5. 9 engines. Detroit Diesel Series 50 are only available with cooled EGR as of this summer. The exhaust gas is tapped pre turbo, routed through a coolant circulated heat exchanger and piped into the intake.



Cummins got away from EGR by going to ISB technology which mostly retarding and super controlled the injection timing. That reduces peak combustion pressures and economy. (Now you know the little secret how 12 valvers kick butt on fuel economy!)



I probably missed something, but brain drain is slowing me.



-John

<font size=1>clarified

</font>