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96 Windsor, C8.3, 275hp. I’m looking to add a few horsepower and torque without breaking the bank and without having to do any kind of transmission upgrade. The C8.3 is the model before ISC 8.3 so little to no engine electronics and a P7100 pump.

With the current power I would be a real hazard on the mountain passes in the West if I had a Toad on behind. Currently I can maintain close to speed limit on not so steep grades. 
 

Has anyone done any upgrades and what we’re your results.

thanks, 

Mike

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I would talk to the seniors at a few Truck Repair shops. I did some stuff on our ISX 525, but won't be relative to your engine. Improving air delivery to the Air Cleaner and exhaust components would be simple and effective to a point.

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Yeah, that’s my ultimate plan, but thought I’d ask here to see if anyone had done something that worked well for them. I know that Cummins made a 300hp version of the same engine and I believe a 325 as well. Don’t know if those were just pump adjustments or full new injector replacement and pump adjustment.

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8 minutes ago, Testdepth said:

Yeah, that’s my ultimate plan, but thought I’d ask here to see if anyone had done something that worked well for them. I know that Cummins made a 300hp version of the same engine and I believe a 325 as well. Don’t know if those were just pump adjustments or full new injector replacement and pump adjustment.

Call or visit a Cummins shop.

Only they can tell you straight 

First handed 😳😏

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I just added a Aero Turbine muffler and AG Diesels Solutions Module. The module really made a difference. I would check with them and see if they have one for your engine. It has a 30 day return if not happy with it. I have heard that the Source Engineering fan makes a lot of difference on the smaller engines. Brazels Rv sells a complete performance upgrade package for some of the engines. Good Luck.

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We had a 97 Windsor with a C8.3.  Great coach.

It's the old mechanical injection system.  You can turn up the power fairly easy. On the top of the pump is a slide that you losen the lock and turn it up. But...

The issue out west is going to be cooling.  Earlier coaches were only 5.9L engines.  In my opinion Monaco shoe horned the larger 8.3 into the lightweight Windsor chassis without adequately addressing the cooling.

We learned to travel at night and avoid towing if temps are above 100. 

Best of luck.

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Yep, that’s something I’ll have to keep an  an eye on. As much as I can tell the radiator stack on the driver’s side is clean and not plugged up at all with dirt/mud/oil so hopefully it has the capacity for a few more HP. I would assume the 300 and 325 versions used the same radiator.

1 hour ago, klcdenver said:

I just added a Aero Turbine muffler and AG Diesels Solutions Module. The module really made a difference. I would check with them and see if they have one for your engine. It has a 30 day return if not happy with it. I have heard that the Source Engineering fan makes a lot of difference on the smaller engines. Brazels Rv sells a complete performance upgrade package for some of the engines. Good Luck.

So I haven’t found any electronic solutions that will do anything. Pre 1998 I believe the 8.3s were all mechanical so there’s nothing electrical that would help that I’m aware of. Improving air flow either through air filter or exhaust can help somewhat if there’s restrictions now.

still looking!

thanks for the reply.

Mike

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21 minutes ago, Testdepth said:

Yep, that’s something I’ll have to keep an  an eye on. As much as I can tell the radiator stack on the driver’s side is clean and not plugged up at all with dirt/mud/oil so hopefully it has the capacity for a few more HP. I would assume the 300 and 325 versions used the same radiator.

So I haven’t found any electronic solutions that will do anything. Pre 1998 I believe the 8.3s were all mechanical so there’s nothing electrical that would help that I’m aware of. Improving air flow either through air filter or exhaust can help somewhat if there’s restrictions now.

still looking!

thanks for the reply.

Mike

I would look at the source Engineering fan because they claim an average of 31 more HP. If you call with your info they will tell you the truth. They told me on the bigger engines no real noticeable power notice. They said smaller engines is where it really helps. They cost about $550. It is really suppose to cut the sound in about 1/2 also.

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43 minutes ago, klcdenver said:

I would look at the source Engineering fan because they claim an average of 31 more HP. If you call with your info they will tell you the truth. They told me on the bigger engines no real noticeable power notice. They said smaller engines is where it really helps. They cost about $550. It is really suppose to cut the sound in about 1/2 also.

Excellent info. I will definitely check with them.

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I don't think the 300 HP and the 325 HP were available at the same time.  So, I'm not sure it's safe to say they used the same radiator/transmission cooler/CAC.  The problem is in order to get more HP you generate more heat.  I had to install a Pyrometer on my 7.3L Ford diesel when I "chipped" it.  It definitely makes a big difference, and generates a lot more heat at the exhaust to the turbo.  I have to keep my eye on the pyro constantly when pulling the mountains towing my boat, it will jump up almost instantly under heavy load.  I believe that all the C8.3L cummins had about the torque, from 275 HP up to 350 HP, but I haven't verified it.  Torque is what gets you up the hill, HP get you down the track faster.  I think you might try some trucker forums, they may have more experience tuning engines for performance.

 

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I would say talk with “banks” i know i have the stinger kit that took me to either 325 or 350 im sure there now longer Avaiable however it never hurts to ask, also when i replaced my radiator 3 weeks ago those vairable fans were still on back order

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23 hours ago, klcdenver said:

I would look at the source Engineering fan because they claim an average of 31 more HP. If you call with your info they will tell you the truth. They told me on the bigger engines no real noticeable power notice. They said smaller engines is where it really helps. They cost about $550. It is really suppose to cut the sound in about 1/2 also.

No way I'd believe a fan swap could save 31hp.  Heck, the fans shouldn't even absorb that much power total.

Whatever fan you run, it has to move the necessary amount of air to cool the engine and transmission. 

I might believe 10hp difference, more likely 5, but 31 is laughable.

There is no free lunch.

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42 minutes ago, dl_racing427 said:

No way I'd believe a fan swap could save 31hp.  Heck, the fans shouldn't even absorb that much power total.

Whatever fan you run, it has to move the necessary amount of air to cool the engine and transmission. 

I might believe 10hp difference, more likely 5, but 31 is laughable.

There is no free lunch.

See the difference $$hear the difference feel the differenceSource Engineering Inc. has developed a line of custom fan blades for most rear radiator diesel pushers manufactured by Monaco Coach. These blades are engine, chassis specific, and can deliver excellent performance while still maintaining the cooling capacity of the stock fan. Some of the benefits include the following:Safari CheetahEngine: CAT C-9 400 H.P. Fan RPM at governed engine speed 2620 HP draw stock blade 42.6 H.P. HP draw Source high efficiency blade 15.5 H.P. Monaco CaymanEngine: Cummins ISB 340 H.P. Fan RPM at governed engine speed 3080 HP draw Stock blade 71 H.P. HP draw Source high efficiency blade 35 H.P. How about more POWER and less NOISE? Increased Fuel Economy. Proven results from 9 to 30 percent depending on the application. Decreased noise levels. these quiet efficient fan blades can decrease fan noise by an average of 50 percent.Increased horse power to the rear wheels. By substantially reducing the parasitic H.P. draw on the engine more power becomes available to the rear wheels, on average 31 Horsepower

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On 6/13/2021 at 9:30 AM, Testdepth said:

 

With the current power I would be a real hazard on the mountain passes in the West if I had a Toad on behind. Currently I can maintain close to speed limit on not so steep grades. 
 

 

Mike

You do realize, practically none of us can climb grades out west, going the speed limit!

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Haha! Yeah I realize that, and I’m not looking to go screaming over the divide at the speed limit. My last trip over the hill east of Butte on 90 I was down to about 40-45. That’s without a toad and not even loaded heavy. This past weekend I went over White Pass in Washington and was down to about 40. That’s not as much of an issue since since it’s a 2 lane. I want to find a small toad and that’s going to just make it worse. 
So far in my research it looks like a different throttle plate in the pump and possibly new nozzles for the injectors would give me probably 75 Hp or so and about 100 lb ft more torque. I’m thinking this is really all I want or need to accomplish what I’m looking for.

Mike

 

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29 minutes ago, Testdepth said:

Haha! Yeah I realize that, and I’m not looking to go screaming over the divide at the speed limit. My last trip over the hill east of Butte on 90 I was down to about 40-45. That’s without a toad and not even loaded heavy. This past weekend I went over White Pass in Washington and was down to about 40. That’s not as much of an issue since since it’s a 2 lane. I want to find a small toad and that’s going to just make it worse. 
So far in my research it looks like a different throttle plate in the pump and possibly new nozzles for the injectors would give me probably 75 Hp or so and about 100 lb ft more torque. I’m thinking this is really all I want or need to accomplish what I’m looking for.

Mike

 

ANY mods to increase power should be preceded by installing an EGT gauge.
Watch the gauge when pulling grades on the stock tune, and be sure to not let EGT get too high after the mods.
You can easily melt pistons by overfueling a diesel for too long a time.

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49 minutes ago, dl_racing427 said:

ANY mods to increase power should be preceded by installing an EGT gauge.
Watch the gauge when pulling grades on the stock tune, and be sure to not let EGT get too high after the mods.
You can easily melt pistons by overfueling a diesel for too long a time.

Agree 100%. I’ve had 2 previous diesels that I “chipped” and exhaust temps really soar when you start pouring the fuel to it. That creates another problem; my other rigs had direct reading pyrometers. Not sure how a pyrometer is set up when there’s 30+ feet between the exhaust manifold and the dash! Hopefully it’s a wire feed and not the tiny copper sense line!

Also what are people using as top exhaust temps? Both my 5.9 Cummins and 7.3 Ford was recommended at 1100 deg.  Is that still a good number for an 8.3 Cummins?

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Depends where you measure it.
I have toe one on my Powerstroke 7.3 pre turbo, and I'll let it go to 1,200.
Post turbo,1,100 should be safe, though it does take longer to respond there.

A gauge for the coach needs to have a rear mounted control box for the thermocouple, and uses a small cable to go to the gauge up front.

Thermocouple wire would be almost impossible to run the length of a coach without breaking it.

I think Isspro used to make them, but that was years ago.

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The EGT gage I installed was from AutoMeter.  An option was an amplifier whose input signal came from a short K-type thermocouple wire from the probe.  From the amplifier, you could simply run ordinary copper wire to the gage head up front.  I mounted my probe in the exhaust manifold within about an inch from the turbo flange.

There are very few EGT-equipped coaches out there.  When I was researching how to lower EGT, I got very few responses from folks when I asked what temps they were getting.  I installed the EGT and FASS system before chipping my ISC-350.  After installing the EGT gage, I spent quite a while experimenting with lowering the EGT.  I did that because in bone-stock condition other than an Aero Turbine 4040XL muffler, EGT's could easily exceed 1400* under modest loads and RPM under 1700.  I thought if they were that high in stock condition, "chipping" would be somewhat risky.

I could find almost nothing online about methods of lowering EGT, so I began experimenting with raising boost pressure.  Mine was 22-23 PSI stock.  Wastegate changes brought it to 31-32 PSI at WOT.  This lowered the EGT about 200*.  Installing the AG Solutions chip brought EGT back up to about what it was in stock condition.  The performance was definitely improved, but it was not dramatic.

In the process of experimenting with lowering the EGT, I got a ton of "Internet parroting" advice from folks not one of whom had ANY hands-on experience.  There were warnings left and right about everything from "deviating from stock configuration" to unsubstanitated advice about what EGT is actually dangerous. I got lots of engineer-wannabes telling me that aluminum softens at 1000*, so that should be my limit.  Of course, anyone with engineering knowledge (or vast personal experience) knows that the temperature of the piston is FAR less than the EGT.  The pistion is splashed underneath with oil for cooling, and riding in a cast iron bore hundreds of degrees below combustion temperature.

I tried unsuccessfully to get an answer from Cummins to what seems a simple question which I'm SURE they had researched: "On a stock ISC-350, what EGT is allowable sustained, and what EGT is allowable for a limited time?"  Never could get an answer.  I just had to conclude that since Cummins did not require EGT gages on our coaches, they were confident their engines could survive the EGT they expected in service, which I experienced could easily exceed 1400*.  And, I repeat, NO ONE had any EXPERIENCE reducing EGT by any means other than throttle and RPM manipulation.

I could get no answer from Banks Engineering, either, as they are somewhat guarded about their proprietary setups.  What I SUSPECT (no personal experience) is that one reason the Banks kits normally included a higher-capacity turbo was more for EGT control than because it was needed to burn extra fuel.

What I can definitively say from HANDS-ON experience is that (1) increasing boost for any given combination of throttle position and RPM will lower EGT, and (2) allowable EGT for short periods is far higher than normally expounded by those with no experience, parroting only what they have read.  When one ventures into uncharted waters, there will never be any shortage of advice from folks who know very little, or can only parrot what they have read.  One self-styled "diesel expert" on iRV2 warned me of higher boost causing "pistons to burn from too-lean mixtures"...it's a DIESEL...let that sink in.

And to explode another myth--raising boost pressure without increasing fueling gives ABSOLUTELY ZERO increase in performance.

As stated earlier by another poster, if you are considering "chipping" or other ways to improve performance, I think you are wise to install an EGT gage FIRST and establish a baseline for EGT on YOUR engine under varying conditions.  I did this also on my 93 Dynasty with the 8.3-250 non-electronic engine before I began changing the fueling plate in the injector pump.  Increased fueling, without increased boost, will undoubtedly produce higher EGT.

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1 hour ago, vanwill52 said:

The EGT gage I installed was from AutoMeter.  An option was an amplifier whose input signal came from a short K-type thermocouple wire from the probe.  From the amplifier, you could simply run ordinary copper wire to the gage head up front.  I mounted my probe in the exhaust manifold within about an inch from the turbo flange.

There are very few EGT-equipped coaches out there.  When I was researching how to lower EGT, I got very few responses from folks when I asked what temps they were getting.  I installed the EGT and FASS system before chipping my ISC-350.  After installing the EGT gage, I spent quite a while experimenting with lowering the EGT.  I did that because in bone-stock condition other than an Aero Turbine 4040XL muffler, EGT's could easily exceed 1400* under modest loads and RPM under 1700.  I thought if they were that high in stock condition, "chipping" would be somewhat risky.

I could find almost nothing online about methods of lowering EGT, so I began experimenting with raising boost pressure.  Mine was 22-23 PSI stock.  Wastegate changes brought it to 31-32 PSI at WOT.  This lowered the EGT about 200*.  Installing the AG Solutions chip brought EGT back up to about what it was in stock condition.  The performance was definitely improved, but it was not dramatic.

In the process of experimenting with lowering the EGT, I got a ton of "Internet parroting" advice from folks not one of whom had ANY hands-on experience.  There were warnings left and right about everything from "deviating from stock configuration" to unsubstanitated advice about what EGT is actually dangerous. I got lots of engineer-wannabes telling me that aluminum softens at 1000*, so that should be my limit.  Of course, anyone with engineering knowledge (or vast personal experience) knows that the temperature of the piston is FAR less than the EGT.  The pistion is splashed underneath with oil for cooling, and riding in a cast iron bore hundreds of degrees below combustion temperature.

I tried unsuccessfully to get an answer from Cummins to what seems a simple question which I'm SURE they had researched: "On a stock ISC-350, what EGT is allowable sustained, and what EGT is allowable for a limited time?"  Never could get an answer.  I just had to conclude that since Cummins did not require EGT gages on our coaches, they were confident their engines could survive the EGT they expected in service, which I experienced could easily exceed 1400*.  And, I repeat, NO ONE had any EXPERIENCE reducing EGT by any means other than throttle and RPM manipulation.

I could get no answer from Banks Engineering, either, as they are somewhat guarded about their proprietary setups.  What I SUSPECT (no personal experience) is that one reason the Banks kits normally included a higher-capacity turbo was more for EGT control than because it was needed to burn extra fuel.

What I can definitively say from HANDS-ON experience is that (1) increasing boost for any given combination of throttle position and RPM will lower EGT, and (2) allowable EGT for short periods is far higher than normally expounded by those with no experience, parroting only what they have read.  When one ventures into uncharted waters, there will never be any shortage of advice from folks who know very little, or can only parrot what they have read.  One self-styled "diesel expert" on iRV2 warned me of higher boost causing "pistons to burn from too-lean mixtures"...it's a DIESEL...let that sink in.

And to explode another myth--raising boost pressure without increasing fueling gives ABSOLUTELY ZERO increase in performance.

As stated earlier by another poster, if you are considering "chipping" or other ways to improve performance, I think you are wise to install an EGT gage FIRST and establish a baseline for EGT on YOUR engine under varying conditions.  I did this also on my 93 Dynasty with the 8.3-250 non-electronic engine before I began changing the fueling plate in the injector pump.  Increased fueling, without increased boost, will undoubtedly produce higher EGT.

Van W, thanks for info. I too discovered some of the same info you are relating here on a ‘02 5.9 that I chipped in a pickup. I pulled a 3 axel goose neck with a 30’ boat and discovered to keep EGT under 1200 was not easy. 1200 degrees was the number that I kept hearing being tossed around as the short term high limit and that 1100 was the steady state max. 
The other area I’ve yet to explore is boost. The max boost I’m able to obtain is 17 lbs. I think that is low. I’d like to experiment with getting that into the mid twenties even before installing a new plate in the pump or injectors. I don’t know if the waste gate is actually set at 17 or that’s just all that amount of fuel will produce.
 

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I SUSPECT (do not KNOW) that most turbo's are limited by their waste gate.  A simple way to determine that would be to simply disconnect the manifold pressure supply to the wastegate and plug the supply tube or hose.  That does not rule out a wastegate that is stuck partially open, though.  You would have to mechanically force the linkage to determine that.  On my coach, the spring for the wastegate was very powerful, and the wastegate could not be operated by hand.  I required a pry bar of some type.

I SUSPECT (do not KNOW) that before my EGT gage installation, my coach operated in excess of 1400* for as much as several minutes without any damage.  Before the EGT gage installation, I had routinely operated it at WOT many times for a short period, like accelerating from a rest stop to Insterstate highway speed, or climbing a mild grade.  IN MY EXPERIENCE it seems the 1200* limit is quite conservative.

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I think that is my next step in this whole process is to test what the turbo will do with the hose disconnected/pinched just to see if it tops out at 17# or it goes higher. I’ve also researched a few EGT  gauges and will pull the trigger on that before making any decisions on fueling changes. 
I too believe that I probably was up into the 1300-1400 range on my pickup before I chipped it. The “chip” was actually a 10 step programmer that went from 0 (not turned on) to 9 ( max fuel). The kit came with a pyrometer to measure EGT. When running on zero, supposedly turned off I seemed to have a bit more power but I could run the EGT  right up through 1300 where the alarm was set. That was running it like I had prior to any adding anything other than the pac brake I added. Bottom line was I ended shifting down earlier and pulling hills a bit slower than I had before. Not what I was looking for!

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Easy enough to increase the HP of 250+ HP mechanical 8.3 which has a bigger turbo and bigger injectors than engines that are less than 250HP. A different profile fuel plate is the main item… I grounded my own based on this picture or a complete kit: https://www.dieselpowerproducts.com/p-9372-tst-power-kit-cummins-83-6cta2A826BEC-E952-4447-9AD8-68624F2C27B6.thumb.png.da0cc546f43addc385e261df2ad5b250.png

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  • 2 months later...

I haven’t updated this thread in awhile so thought I would do that. I did install an EGT (preturbo) and ran with it for awhile to see what my temps were doing. Ran some tests by installing a needle valve in the pressure line to the waste gate and varied the setting from normal to completely closed. max boost never changed. To me that pointed to bad/worn turbo or leaky charge air cooler. With only 75k miles on the motor I opted to check the CAC. I built a test fixture I found on YouTube and tested the CAC. Could not get it to pressurize! 

Long story short, found a failed weld with a hole about 3/16 x 5/8”. TIG welded it closed, tested found a couple of pinhole leaks that weren’t weldable so I epoxied them. Retested reinstalled CAC and on initial test drive was able to achieve just over 20# boost. 
I’ll be doing a more extensive test drive to include some longer steep grades to watch boost and EGT.

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14 hours ago, Testdepth said:

I haven’t updated this thread in awhile so thought I would do that. I did install an EGT (preturbo) and ran with it for awhile to see what my temps were doing. Ran some tests by installing a needle valve in the pressure line to the waste gate and varied the setting from normal to completely closed. max boost never changed. To me that pointed to bad/worn turbo or leaky charge air cooler. With only 75k miles on the motor I opted to check the CAC. I built a test fixture I found on YouTube and tested the CAC. Could not get it to pressurize! 

Long story short, found a failed weld with a hole about 3/16 x 5/8”. TIG welded it closed, tested found a couple of pinhole leaks that weren’t weldable so I epoxied them. Retested reinstalled CAC and on initial test drive was able to achieve just over 20# boost. 
I’ll be doing a more extensive test drive to include some longer steep grades to watch boost and EGT.

Nice troubleshooting.  Low boost will cause high EGT's, and will eventually damage your engine.  Good catch.

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