Engine/Transmission (1994 - 1998) High Egt's - Why?

[SlyBones]

Reddog1,



With the AFC housing off, ever notice that little arm that sticks down? Ever notice how the tops of cam plates have a notch down the center of them, with the piece the governor lever hits agains hanging down one side.



What happens when you hit the throttle is the governor lever moves forward until it hits that arm. Once the turbo starts to make boost, the boost pushes against the diaphram in the AFC housing with the spring providing the tension or resistance. As the boost pushes the diaphram, compressing the spring, the arm moves forward, therefore allowing the governor lever to move forward adding more fuel. This happens until the arm has been pushed forward to the point where it is fully retracted into that slot in the cam plate and the governor lever is now touching lower face of the cam plate. From there the governor lever rides up following the curve of the plate.



There is a bit more to it, but this give enough to see how the valet switch works. The valet switch blocks off the boost from the manifold to the AFC housing. So the diaphram and the arm dont move past that initial bit. The governor lever never hits the cam plate etc. -- The amount of pre-boost fueling is what dictates the power you have in valet mode. Changing the cam plate should not effect valet mode. Adding injectors for example should add power in valet mode.



Amazingly enough is fairly good power. I would say that the first 1/3 throttle is no different in or out of valet mode. I have fogotten I have turned it on. Drove around for a day or two before I finally stuck my foot into it enough to tell something was wrong.



Once it saved me a ticket. Someone wanted to play on the freeway. Forgot it was on, and didnt notice during the teasing phase. Then we both nailed it. She took off, I had a dumb look on my face. WTF. Crap. Then I looked up to see the WSP parked on the side of the freeway. She got pulled over, and I happily drive on.

 

[SlyBones]

I also think its fair to point out that most of us are not in the state of denial. We know our pyro's will go past 1300, we know the consequences of running there, and accept them. We have learned to drive appropriately. Its the risks we are willing to take to have our fun. -- I guess that I just wish there was a better way to compare EGT's. We can tell our pyro readings but there are no standard test conditions we all follow in obtaining them. So for me the pyro readings are subjective and and based on peoples personal level of risk acceptance.



A few sayings around here. --



"I am my own warranty station"

"You want to play, you got to pay".

 

[renegademike]

I was having the same problems w/ high EGT and alot of black smoke and we replaced the diaphragm in the injecter pump and my EGT,s went way down. I still smoke when I step on it but not as bad as before.

 

[Reddog1]

Deezul 1 - I may stand corrected, but I would think that the turbo lag would be less noticeable with a manual transmission. I base this on the thought that you have a more control as to when the gears (clutch) are engaged. If I remember correctly, Piers told me that the HX40 turbo lag was greater on the autos than the manuals, at least more noticeable.



One of the ways I check my turbo lag is hold a steady throttle on flat ground. Check the time from pedal to the floor and boost serge. Not the most efficient method, but measurable. The best I have been able to do is 1. 4 seconds.



SlyBones - After making my post, it occurred to me that yes, the AFC does control fuel before boost. You can have zero boost at any speed. I got a little to focused on EGTs, and went brain dead. Now, I can understand what you are doing with the valet switch.



I agree that most of us are not in the state of denial on the EGTs. I do think we treat the subject too lightly when encouraging others to modify their Rams. I have found that most of us are a bit shy in expressing our concerns and efforts in reducing EGTs.



Would we still modify our Rams? I think yes, but with more awareness of the trade off.



renegademike - With my limited knowledge, I would think that a malfunctioning diaphragm would have a similar effect of the valet switch in the no boost mode. I wonder if the reduction of EGTs was a result of changing the AFC adjustments?



Maybe someone can give us some help here.



Wayne

 

[Jim Fulmer]

My old set up was a #4 plate . 050 back from stock, 370's and 191's and 4K's with a BHAF for a filter and I could go from 600-1500 EGT in 3 seconds, does this count for being over fueled



Jim

 

[Reddog1]

Jim Fulmer - I think I can match that. Oh , I forgot, the objective is to increase that time, not reduce it.



Did it require the twins to increase the time?





Wayne

 

[Jim Fulmer]

It went from the above time to not being able to get over 1400 at 110 MPH with the Twins, then the plate went all the way forward and it would peg(1500) around 90 MPH, then I put on the Big AFE and EGT's dropped say 150 degrees, now they range between 1400-1500 depending on the outside conditions. That's at 57 ish boost unlocked, 60 locked.



Jim

 

[ablakemore]

Timing

Wayne,

We still need to get some guys together at your place for that "Timing Party" we talked about at the Dyno runs in Sacramento couple weeks back



Allen

 

[MDKram]

Wayne, one thing to keep in mind as you probably know, is every power mod is not additive just as every EGT reduction attempt is not additive. When you are told that a 16 cm2 housing will give you 150 - 200 *F drop and timing will net you 100*F drop... . This is true to some extent if only that mod is done. Don't get me wrong, they all MUST be done, but don't expect total EGT control with lots of fuel unless you invest some serious dollars starting with a larger turbo and a cam.



For most, a larger exhaust housing and advancing the timing is a realistic undertaking. You will probably see a 200*F drop in EGTs by going to a 16 housing and advancing the timing to 15-16* neighbourhood. You will still get things hot if you stay in the go pedal, it will just take longer for the EGTs to rise.



Last weekend I "played" with Swamp Donkey's truck and we made a noticeable difference in how fast the EGTs rose under power by advancing the timing. I know SD still has EGT problems but he now has 10 seconds of full power instead of 3 seconds. I am looking forward to see how effective his 16 housing will be in giving him further EGT reduction with his combination of BOMBing mods. I'm guessing he will be able to stay in the go pedal for maybe 20 seconds?!?!?



As for spool-up: With the 370's, spool-up is not really an issue. Those injectors will spool a 16 housing pretty well even in the auto transmission with an 89% converter. To keep smoke under control while loaded will take some driving finess. Apply light throttle to build some boost (8-10 psi) then roll into it. You can play with your AFC housing position and star wheel to give you acceptable smoke versus spool-up.



... just my $0. 02 worth, Marc

 

[1dslram]

I have about the same mod's and the same EGT problem. The timing and 16cm2 housing helped but i have moved my #5 plate as far back as possible. I am going to either the HX40 compressor housing or a new turbo from either Pius at Bell Turbo or a PDR 40.



It is true that if you roll into the throttle until about 10#-15# boost then floor it EGT's go up slower, and smoke is reduced dramatical. My problem is not only high EGT's, black smoke so obviously I need more air, to be added at a later date, funding permitting.



Bruce

 

[Koa Man]

1dslram,

Your truck and mine have almost identical mods. I have the Pius modified HX40/16. EGTs are not a problem when not towing or towing my small chipper (3K lbs. ) When towing my big chipper (8K lbs) I can keep my foot in it pretty good, but EGTs will easily run over 1300* if you try to quickly accelerate up a hill. If you let the speed build up slowly, then it is very controllable. I have my plate just a hair back from the middle position. It ran too hot when I had it 3/4 forward when towing, and I tow almost daily.

You will like the HX40. I have absolutely no hesitation, even when taking off uphill from a standing start. Beat a Nissan Xterra the other day from the get go at a stoplight. Guy was changing lanes and cutting in front of cars to be the first at the light alongside me. Was almost like the Dodge commercial, as I was towing my small chipper. Let him go after 50 mph.

 

[1dslram]

Koa Man

Thanks I talked to Pius about 2 wks. ago and he said that he is working an a different turbo, that if it works out would be even better than what he has at the present. Oo.

 

[Reddog1]

SlyBones - I have been reading and rereading your post on the valet switch. Since you made the post, I have blocked off the pressure to my AFC, so that I could personally experience the results. I could not find a gal like you did, so I missed that part of the test .



I made several observations and came to several conclusions. I want to think them through carefully, and make them their own post.



I would suggest everyone really concerned with EGTs to read your post carefully. I think it was very informative with a great safety net. Thanks.





ANYONE - Please comment on renegademike post regarding the AFC diaphragm . JohnE, are you there? Give us your thoughts.





Jim Fulmer - You have surpassed me with both power and EGTs. I hope you will continue to share your experiences with us on this EGT issue. Especially if you see we have a misunderstanding.





ablakemore - I would still like to get the party together. As you can see by that Thread, you and I are the only ones in the Sacramento area with stock timing.





MDKram - With all do respect, don't treat "10 seconds of full power instead of 3 seconds" as ho hum. Sounds great to me Oo. . Keep us posted on each second you gain.



I hope you are right about the spool-up with the 370 injectors 16 housing. I have a weak lead on a HX40. If that materializes, I will probably go that way. Either way, I will probably order the 16cm non-waste gated housing from Piers.





1dslram - Let us know how your EGTs are effected when you get your new turb.





Koa Man - You got a cummins on your chipper too?







Wayne

 

[Koa Man]

Originally posted by Reddog1





Koa Man - You got a cummins on your chipper too?



Wayne

The big chipper has a 200hp Cummins 5. 9BTA with the P7100 pump. I was wondering if I should put a plate in it to boost the power to around 230-250hp.



The small chipper has a 40hp Yanmar diesel, which is a good engine too.

 

[Hammer]

Reddog1,

My question for you here as my eyes are now looking like this from all this reading would be this,what is the main quest for the lower egt's,hp wars or towing?. The reason I ask this,and I am certain it was asked before,is in order for one to attack the problem he has to know where to start. There is alot of members here who seek the eternal compromise that will allow max hp blasts and still be able to use ALL their power to tow their 5vers,I myself know that will not happen and those who say it can be done are feeding you bunk. One will have to suffer to make the other work. There is alot to say about overfueling,airflow restrictions and the amount of wasted money by people who try to make it work and lower egts,but,how many will honestly tell you about what they did that did not work. Most times they get into parts sales mode and all they want to do is promote what they gained and not what was sacrificed to do it.



To lower egt's most already have given you a baseline to start with. My recommendation is do or try each thing one at a time and see where you get to from the initial baseline you have. To get lower you will need to change other things(like increasing airflow,changing fuel curves and application,ported head or different camshaft)and it will take time and money,there is no quick fix. While the 370's are great for power they do have their problems with smoke and egt concerns due to their spray pattern and our piston top not being designed to meet their pattern to allow for proper combustion. There are other more efficent injectors that will allow the same power and be more efficent and help with your egt's. Old diesel man once told me that if there is no smoke from the chimney their is no fire in the oven,while that may be true to a point,once you pass the point of efficency what does all that smoke mean,high egt's and poor efficency that will kill hp and your motor eventually. Trick is how to get people to open up on what will make your truck efficent and still make good power with egt's in check. Now thats one of the things you'll find most of the high hp guru's hiding,because once it solved it will be a money pit for them and more money out of our pockets.



I often wonder how the guys with twins do towing with egts and why they are not open and honest with their answers. Twins will lower egts greatly while not towing and allow the longer throttle burts,but,they also hurt in heavy towing due to egts. I know of 2 high hp eastern trucks with them of which the owners have told me honestly about high egts during a long sustained heavy tows and hill drags with a big 5ver. One of the gentlemen had even explained the throttle feel during his towing with the throttle getting spongy the longer the tow. Twins help,they look neat,make lots of boost,but to me are still only a bandaid fix on a big problem.



One of the premier race engine builder out my way and I have chatted about this and his take is a simple one,find the fine line of balance between fueling and PROPER airflow and its distribution and egt's will come in line. I asked him for a honest opinon in if it could be done cost efficently and his answer kinda made me laugh,air + fuel= Power. Asked him if he was snooping in the diesel boards as Joe D had already said that once and his comment was to smile a little and tell me this is not rocket science. All internal combustion engines need the fine line danced for max power with low egts,time,hard work and money will need to be utilized to accomplish it but it can be done. One thing I have learned here is to read all the hype and stories,sort thru it myself,through out the 70% that is BS and retain the rest,it will help. Shame we have to do it that way,but,someday it will stop,maybe.



Now where do we go from here,onward,I am to windy so I'll leave with this and don my flaming suit also. Way to many people here are concerned with max power without a cause for egts and that can and will create a problem for the newbies coming aboard. All they see is the numbers being laid down and what parts were used in attaining it,not,what is or may happen as a result of it. More responses,both the negative and positive,need to be told so all can learn from each others experiences. Just my thoughts and opinions... ... ... ... Andy

 

[Boldt's Wagon]

I thought I would add another log to the fire. In the debate of what you want swings on max power for racing or max power for towing on those long grades. The other consideration in long applications of power while towing is cooling and the engine coolant temperature while towing at high power levels.



My opinion is that the maximum sustained power at the wheels is 275-300 HP at higher altitudes, over 8,000 ft. At these power levels the engine coolant will get up to 210 degrees with the stock cooling system (remember the fan has kicked in and is now sucking up 20-25 HP). The trick then is to keep the EGT at 1250 or less when the engine is pulling at 2200-2400 rpm.



If you have an engine that will deliver higher power levels it will also deliver higher EGT and coolant temperatures. You may be tempted to use the power (that pesky Ford) or have an unknowledgable driver towing that particular grade that results is sustained operation at engine damaging temperatures.



With the adjustable fueling boxes for 24 valves, it would appear that you can have the best of both worlds, towing and performance.



My goal is tune my 12 valve engine and transmission controls so that it is idiot proof and does not require monitoring of gauges to avoid damage. Only time will tell if I have attained my goal. I still have to monitor the EGT for cool down when towing.

 

[Reddog1]

Koa Man - We need to get you hooked up with Dodge advertising. Cummins front and real LOL





Hammer - I can see no reason to don you flaming suit. I appreciate your post. Judging from the number of hits on this thread, it would appear there is a lot of interest in this subject.



The main quest for the lower egt's, hp wars or towing? Actually, my personal interest is both. Do I think we can have both? Not really, but I for one would like to know my options, and what to expect along the way.



Through this thread, you and others have helped me put a lot of this in perspective. You and others have helped me to understand a little more about my Cummins. As to the BS, I am not so sure that it is only 70%, and I doubt it will ever stop. So far, on this thread, the BS appears to be exceptionally low.



As you recommended will try each thing one at a time and see where I get from the initial baseline I have. I think the various posts will be of great help.





Boldt's Wagon - I share your goal in tuning my 12 valve engine and transmission controls so that it is idiot proof and does not require monitoring of gauges to avoid damage. The only way to do that is to prompt others to share their experiences and thoughts.





I think our trucks are capable of more than 180 to 200 HP. Where do we stop, I do not know, that is one of the reasons for this thread.





Wayne

 

[Jim Fulmer]

Jim Fulmer - You have surpassed me with both power and EGTs. I hope you will continue to share your experiences with us on this EGT issue. Especially if you see we have a misunderstanding.



If you have a question ask it, I don't have any secrets!



I wish I could give you some info on towing with Twins but this is just a daily driver.



Jim

 

[Deezul1]

Reddog1

My compromise between high HP for regular driving and a occasional Mustang GT attitude adjustment session and towing has been to set my AFC housing up so I can reset the plate in less than 5 minutes. I run it full forward except when towing time comes and then slide it back about 1/8th " and that makes a good difference in usable EGTs and keeps the soot off the trailer too. I still have plenty of towing power by doing that and it took a few tries to find the sweet spot.

 

[Reddog1]

Jim Fulmer - Being a daily driver only provides half the picture. This is unacceptable, please find a couple PH**Ds, tow them and report the EGT results. LOL



Thanks for the post.







Deezul 1 - I have given thought to using the method you use. A witness mark or something similar for the AFC Housing. One position empty and a second position towing. I have already replaced my AFC screws with Allen heads.



SlyBones has a very effective method using the valet switch. It is perhaps a little more extreme than repositioning the AFC, but definitely easier, and done on the fly.



I will probably use both methods, depending on which works best at the time.







At the risk of sounding mean spirited, the fellow on the "95 Auto Power" thread could sure use some input. There are a couple of potentially dangerous post as well as a couple of good ones. The good ones could use some support. This might help the fellow that started the thread get constructive responses and sort through the BS.





Wayne