Engine/Transmission (1994 - 1998) Fuel Plate Tech question and opinion on DST #5 profile

[PGWIN]

I'd like to get a #5 plate, from my CPL 1550, 95' 175/420 manual trans, with current mods of gauges, starwheel full forward, plate full forward, AFC housing full forward producing a slight haze of smoke if hammering from idle.

I'll use this for towing 12-14k fiver and certainly need torque in the 1400-1850 rpm range, that's the sweetspot I like to drive in, maybe not ideal but engine noise is comfortable in this range for long duration.


I've studied the fuel plate, governor arm, and anneroid AFC system that i believe i understand exactly how it works, except for:

One thing i don't understand about eh stock plate and other plates that don't have a smooth ramp profile (abrupt notches), much less a continual and smooth negative ramp (like the 100 plate), it would seam the gov arm would not be able to continue following the profile as rpm increases unless when the arm moves up it would finally force its way over the abrupt bumps but delayed compared to following a smooth profile. I'm just about positive i'm missing something here as Bosch obviously have top notch engineers so i'll consider myself not in the "know" and ask the question.


Next is - of the TST plates, I like the #5 for torque i can get, and i like that plate because it has "smoother" than stock ramp profile. I like the 100 ramp profile as it seems the gov arm would be very happy. But i'm looking form midrange torque (really 1500-1800rpm) priority 1, and a bit more torque on the higher end to help me wind out to more than 2600 rpm tops (currently) which i may need 3K GSK but this provides the fuel for that.


Along these thoughts the SDT #5 has a profile that looks ok for the gov arm to follow. has any one used this or have any experience with it compared to TST#5 profile?
http://www.ebay.com/itm/SDT-5-Fuel-...3200463&pid=100005&rk=3&rkt=6&sd=261869811191




Thx for your help!

PGWIN

 

[GAmes]

I don't have any experience with a #5 but I have plenty of experience towing. If you are going to be pulling a 12-14k trailer a lot, start putting money away for transmissions. I went through 12 (no exaggeration) NV4500s before I upgraded to a G56. You might try tightening your gov springs a click (or two) before investing in a GSK. I recommend the towing profile plate like the one I have. It was developed by a Bosch shop owner who tows with a '96 Dodge/Cummins. You can call http://theaustinfuelinjection.com/ for more info.

You might be interested in the info in this link as well.

http://www.cumminsforum.com/forum/9...ers-claimed-hp-increases-your-year-truck.html

A little bit of googling should get you to a video of how the gov arm works.

 

[Bob4x4]

The 5 plate will make good power on a 5 spd truck but will not like towing heavy without other up grades.I think in your case you would be better served by a 10 plate and gsk to help with the big gap between gears on the 5 speed.It,s no fun needing to keep your truck held back to hi egts when trying to enjoy the scenery

 

[PGWIN]

I don't have any experience with a #5 but I have plenty of experience towing. If you are going to be pulling a 12-14k trailer a lot, start putting money away for transmissions. I went through 12 (no exaggeration) NV4500s before I upgraded to a G56. You might try tightening your gov springs a click (or two) before investing in a GSK. I recommend the towing profile plate like the one I have. It was developed by a Bosch shop owner who tows with a '96 Dodge/Cummins. You can call http://theaustinfuelinjection.com/ for more info.

You might be interested in the info in this link as well.

http://www.cumminsforum.com/forum/9...ers-claimed-hp-increases-your-year-truck.html

A little bit of googling should get you to a video of how the gov arm works.

Thanks GAmes fo the info and link. I envy the 6spd manual and it may be in the future after I get through this and see how I like it.

The link is interesting. What is never clear from the plate profiles is where the gov arm hits wrt RPM. Which would give an idea of the difference. Interesting charts though - I've seen the TST chart for years now, but not the others.

It is interesting that TST doesn't recommend #10 and higher for the 95 manual, any idea why this is the case (doesn't provide enough fuel / and he considers 8, 6 to be able to handle EGT for towing)? I would have to think this chart is for towing applications where you can hammer a 5 mile hill at 7% grade with a heavy llload and not overheat on EGT's(?) rather than just "sporting" around town?

For the Austin link - I looked at it but didn't see any plates - given I'm in California a custom plate from them may not be too easy. But thanks.

Thx,

Paul

 

[PGWIN]

The 5 plate will make good power on a 5 spd truck but will not like towing heavy without other up grades.I think in your case you would be better served by a 10 plate and gsk to help with the big gap between gears on the 5 speed.It,s no fun needing to keep your truck held back to hi egts when trying to enjoy the scenery

Thx Bob4x4 -

given the recommendation for a #10 plate, is that with my 95' 175/420 engine/pump in mind which has a much lower response to the #10 plate compared to the other pumps (i.e. 98' 12V truck)? The TST chart doesn't recommend #10 for this pump - perhaps because it is a much lower output pump-given delivery valves, and other pump internals - guessing?

Do you know if the #6 can not keep EGT's below 1250 on a big 5mile hill, hammer down with heavy load at 1800 rpm with out other turbo mods, assuming I have 30lbs boost? I think the key on this is exactly which pump it is?

Given I have no real experience with different plates myself, and peoples experience is largely all over the map and not always apples to apples modifications to compare plate response to, its really hard to make sense out of all this "data" and I've studied it for a long time.

At some point I can see buying 2 or 3 different plates not knowing what to expect, to try and get it right - if the charts are not indicative of performance for extended dudurations. Then I'll need several plates to figure it out at $200 a pop, which makes me want to buy a $50 Ebay plate to keep the learning curve cost down?

Thx for your insight - appreciated.

pgwin

 

[GAmes]

You have a lot of expectations, It would take towing twin turbos and I don't know what else to "hammer a 5 mile hill at 7% grade with a heavy load and not overheat on EGT's(?)" Here is some advice from real world experience. Your transmission will last a lot longer if you limit your boost to 20psi, especially in 5th gear. Your cooling system will thank you also.

I don't know of any plate that will " keep EGT's below 1250 on a big 5mile hill, hammer down with heavy load at 1800 rpm with out other turbo mods, assuming I have 30lbs boost" It is the fuel in the chamber, not the plate, that determines what your EGTs are. Refer back to the first paragraph. Also, the stock turbo won't last long if you push it to 30 psi a lot.

I posted to call them for more info. The plate can be easily mailed, but the owner of the shop can provide you a ton of information about installation, what to expect and much more. After the stock plate and a #11 plate their towing plate is the only one I would recommend to anyone towing a heavy trailer. The difference in torque output at low to medium RPM is amazing. Add some bigger injectors and you would be in towing heaven.

As for the GSK, my engine would go to 2850 or so from the factory. A little tweaking of the stock springs and I can get full fueling to 3100 RPM.

 

[PGWIN]

You have a lot of expectations, It would take towing twin turbos and I don't know what else to "hammer a 5 mile hill at 7% grade with a heavy load and not overheat on EGT's(?)" Here is some advice from real world experience. Your transmission will last a lot longer if you limit your boost to 20psi, especially in 5th gear. Your cooling system will thank you also.

I don't know of any plate that will " keep EGT's below 1250 on a big 5mile hill, hammer down with heavy load at 1800 rpm with out other turbo mods, assuming I have 30lbs boost" It is the fuel in the chamber, not the plate, that determines what your EGTs are. Refer back to the first paragraph. Also, the stock turbo won't last long if you push it to 30 psi a lot.

I posted to call them for more info. The plate can be easily mailed, but the owner of the shop can provide you a ton of information about installation, what to expect and much more. After the stock plate and a #11 plate their towing plate is the only one I would recommend to anyone towing a heavy trailer. The difference in torque output at low to medium RPM is amazing. Add some bigger injectors and you would be in towing heaven.

As for the GSK, my engine would go to 2850 or so from the factory. A little tweaking of the stock springs and I can get full fueling to 3100 RPM.

Thanks GAMEs for the detailed answers and bearing with my questions.

Ok - that helps on the profile knowledge, a plate isn't necessarily designed to maintain EGT temps for long duration (such as 5 mile hill loaded), but some "may" control EGT's long duration depending on how setup for the fueling of that truck - in specific RPM ranges (i.e. perhaps a #10).

I think I will call both TST and talk to him about it and also Austin wrt towing heavy and being able to hammer get up a long grade and not be getting run over by the big boys off on the shoulder (that's literal risk currently!). Around here, west cost, we have long grades on HWY 5 and HWY 80 where it will be 7% grade for 5 miles, currently i'm stuck in 3rd gear at 35mph pedal to the floor at 2000 rpm, and sometimes (rarely drop to 2nd gear (15 mph), only one trip and not attempting that again w/o more power.

The GSK is an excellent point and I will see what I can do with a click or two on each of the two adjusters - that would sure help, as but the time I shift I'm right at 1400 rpm and can' t pull up to 1500 rpm (and stock -EGT's going up of course in this range) - back down to 2nd gear!. If I can get to 28-2900 rpm while pulling the load up the hils that would keep me in the torque band for the shift.

As for the turbo, I like our point on that. I think the approach I will take is install a plate mid position, then increase boost as required to control EGT's, then if that's not enough power, increment plate fwd/increase boost and iterate until I have enough. I'm not looking for a rocket ship, but enough torque to be able to pull these grades at hopefully 40-45 MPH without fear of dropping out of the torque curve.

I'll really appreciate the points you and Bob4x4 have brought up to think about - most helpful.

Currently i'm going through my fuel system (reading Joe G's most excellent article) to make sure I am not ingesting air in the fuel pre-filter and lift pump, to be sure I start from a good baseline vs. chasing my tail. I only make 14psi boost now and sometimes only 12psi, its not consistent. So I believe 17psi is factory setting for the 95' manual (not positive), maybe it is fuel related or maybe waste gate is set low. At this point I have done fuel preheater delete, new fuel pre-filter/oring (prior was pretty clean/oring a bit crispy if scraping with fingernail!), and am replacing the filter to lift tube that had internally ssplit ends.

For the primer button, the rubber cap had (2 drops of fuel in it?) when I pulled it off, but I had not pressed the primer button. When I pressed the primer button w/o rubber cap on it I got a teaspoon of fuel coming out of the plunger I think. So pulled that, replaced the oring around the threads, and will need to get the smaller plunger Oring tomorrow ( I think the small O'ring in compression by the spring is really what seals it in its static position - it is not a tight sliding fit for a dynamic seal (at least mine isn't!). I'm not sure if the fuel coming out of plunger is a sign it may be leaking air into the system or not, maybe and maybe that is causing spungy fuel and less than normal fuel volume injection which may explain why strar wheel and AFC housing full forward only produces a haze of smoke stomping on if from idle, though it has always started instantly over the past 14 yrs I've had it.

I probably should get a fuel pressure gauge installed so I know the health the fuel deliver.

Well i'm quite enjoying figuring out exactly what is going on. Can't wait to get through this fuel system phase and get a plate in.

 

[GAmes]

I think I will call both TST and talk to him about it and also Austin wrt towing heavy and being able to hammer get up a long grade and not be getting run over by the big boys off on the shoulder (that's literal risk currently!). Around here, west cost, we have long grades on HWY 5 and HWY 80 where it will be 7% grade for 5 miles, currently i'm stuck in 3rd gear at 35mph pedal to the floor at 2000 rpm, and sometimes (rarely drop to 2nd gear (15 mph), only one trip and not attempting that again w/o more power.

I guarantee I have many more miles of CA highways behind me while towing with a pickup than you do. Even with my engine mods I have been at 35mph climbing the grades to Donners Pass, Bakers grade, Hwy 395 and I5 over the Siskiyous. It isn't any easier in SoCal either. Now that I have a 6 speed I climb those same grades a little faster since I have usable 4th gear, but it still isn't at the speeds of the typical CA driver who thinks he is on an Indy track. Also, "getting run over by the big boys off on the shoulder" is a paranoia that has no basis in fact. If you really want to pull your big trailer up mountains at 60 mph I suggest you trade your Dodge for a truck capable for that job. It would be a snap for a class 8 truck, but I'm sure there are others with big engines, HD transmissions and cooling systems that would work.

 

[Bob4x4]

The 94/95 pumps are not going to turn the same rpm as the 180hp later versions.The 10 plate ramps up nice and defuels as rpm(use a gsk) rises to where the 12v head does not flow enough air,The plate can be slid forward if your set up will allow more fueling,Trying to get more speed up the big grades will call for more than just a plate.My 94 would pull any grade in Cali at above the speed limit but it took a few bucks to get it there and took out the 5 speed twice

 

[MLee]

In order to get the pump springs the same I used a digital caliper and measured .055" nut to stud end. It pulls pretty good to the 2950 point.I have the stock plate in and just a hair back of full forward. My sig shows a #5 but the foot would dive under the plate on occasion, because of the way it was cut, so I don't have it installed now. Joe D recommends a different one for the 175 engine, a bit more mild. I think that altitude makes a difference to your sea level to my 4500 ft elevation. air difference in density.
But as stated you have to experiment with position of the plate to get what your looking for, and to keep it safe towing.

 

[PGWIN]

Well back to this Chapter. I took a detour to ensure the fuel system pre-pump was in decent condition - phobia of air leaks. I found the lift pump had a non-functional check valve on the outlet (broken). I've replaced pre-prefilter, deleted fuel heater, ne pre-filter, new pre-filter to lift pump hose, new fuel filter. I didn't check the fuel pressure as I don't have a gage...... but would assume it is good given a new lift pump. I have not checked the spring length in fuel overflow valve yet.

Here is the current performance with star wheel, stock plate, and AFC housing all full forward.

- Max boost - 12-14 PSI
- Idle no load and briefly mashing throttle - produces a puff of smoke - visible and translucent ( I'm just looking or decent fuel delivery in this).
- If in 2nd gear at 1200 rpm and i mash on the peddle - i'll bet a bit of smoke until the turbo catches up 1500rmp or so then it clears up completely.
- Hammer throttle at 1600rpm - just accelerates - no visible smoke in the mirror.


- With turbo waste gate pressue tube plugged completely I was expecting an increase in turbo boost. Flat roads, in 3rd gear i can get to 15psi, and occasionally 17psi. On a large grade i get about the same, sometimes it gets to only 13psi sometimes to 17 - but i have to work really hard to get it to 17psi.

So does this sound right? Is it simply not producing more boost because it doesn't have enough fuel to do so? Remember this is the 1995 175/420 pump?

 

[Bob4x4]

The 94/95 would get about 18 psi stock (avg of many trucks).Check for boost leaks and fuel psi at pump.You will need an adapter for the banjo bolt to connect a gauge.I doubt your overflow valve is up to spec after all these years.

 

[MLee]

stretch the over flow valve spring to .055" just over 1/2" and yes that is in the ball park for boost from the era.Line Plugged should be little more.

 

[GAmes]

I didn't check the fuel pressure as I don't have a gage...... but would assume it is good given a new lift pump.

So, you haven't read Joe G's fuel system write-up. The pressure isn't produced by the pump, volume is. Pressure is caused by a restriction, in the case of a 12 valve, the OFV. You need a fuel pressure gauge to proceed.

 

[PGWIN]

Got it - I'll get a gage and check spring length as well.

thx

Bob 4x4 - I think I found a boost leak right at the turbo exhaust coupler. Installed incorrectly is my guess a long long time ago under PO ownership.

It was hard to tell, but the compromised edge I believe may not have been clamped, and was more abrading against the edge of the clamp.

The remainder of turbo hoses have integrity. I didn't take the clamp off the turbo exhaust port and connecting tube. Is there a seal in there I should get and replace?

 

[Bob4x4]

Yes there is an o-ring between the outlet adapter and turbo.The adapter is what allows you to align the cac hose tube assy to fit the best possible.The o-ring is a special material that can withstand the high temps the compressor puts out

 

[PGWIN]

I re-installed the existing boot until I can get a new one. Pretty sure it seals now the way it is installed. But I will get a replacement - can I use a straight tube here or do I need the bulge in it to allow for movement of engine?

Pulling a 3K lb boat today with it, on the flats - no hills, in 4th gear I can get 17-18 PSI boost at about 2250 rpm, that again with the waste gate disabled temporarily. Maybe it will go a bit higher on a big hill - not sure. Oonce I shift to 5th, rpms drop to ~15-1600 and of course i'm back at 13psi boost and climbing very slowly. In current form I think it takes >2k rpm with hammer down to get to 17-18psi boost.

Does this sound "healthy" boost wise for mostly stock on the 175/420?

Thx,

pgwin

 

[JKosten]

Couple of questions:
Which turbo do you have?
Do you see any dust inside the boot?
Have you changed your pump timing?
Do you have an EGT gauge installed?

As for the original question on the fuel plate, just remember that it is only a fuel stop plate, that limits the fueling based on engine RPM. The real performance comes from how the governor, and AFC are adjusted. If the AFC spring is too tight you will not have enough fueling as compared to air, and the inverse: if the AFC spring is too loose then you will have more fuel than air. This adjustment is based on the turbo reference and how the engine has been modified. The fuel plate only comes into play when there is more fueling requested at a lower rpm that is typically below the boosted range and would result in unburned fuel, aka smoke.

 

[PGWIN]

Turbo is stock from 1995 175/420 - is that HX35?
I looked specifically for dust - don't see any with a flashlight or by wiping with an cotton cloth.
Pump timing. I haven't changed PO didn't say he did. He did say he had the injector tips modified -to not void warranty but add more fuel (~1997). I assume this meant extrude honed?

I do have EGT gauge, best I could do pulling 7K trailer up 7% grade for 5 miles, in 4th gear at 1800rpm ~1100 pre-turbo, and at 1600 rpm I was at 1200/1250 and dropping a gear 3rd (5sp) at 35 mph.

Perhaps my AFC spring is "too strong" or a resistance to the foot moving fwd at normal boost. That is what I was hoping the extra boost would do - for the case the arm was not contacting the plate.

Couple of questions:
Which turbo do you have?
Do you see any dust inside the boot?
Have you changed your pump timing?
Do you have an EGT gauge installed?

As for the original question on the fuel plate, just remember that it is only a fuel stop plate, that limits the fueling based on engine RPM. The real performance comes from how the governor, and AFC are adjusted. If the AFC spring is too tight you will not have enough fueling as compared to air, and the inverse: if the AFC spring is too loose then you will have more fuel than air. This adjustment is based on the turbo reference and how the engine has been modified. The fuel plate only comes into play when there is more fueling requested at a lower rpm that is typically below the boosted range and would result in unburned fuel, aka smoke.
View attachment 96033

View attachment 96034

 

[JKosten]

Check the data tag on the turbo for the model number. My 96 5spd truck ran up to 32lbs of boost with the stock HX35 turbo. The HX35 has an efficiency choke point of 35lbs. It will create up to 50lbs of boost, but after 35lbs it begins to superheat the air.

I would recommend getting the AFC adjusted then trying to get your boost up into at least the mid 20's. I adjusted my AFC with a regulated air supply and set max travel at 32lbs of boost. That way it had a matched fuel to air ratio. I ran a #100 plate and did not have any smoke issues, unless I purposely shifted way early.

How is the exhaust system? Stock? Getting air in and out of the engine is the best way to help it perform well.