Engine/Transmission (1994 - 1998) Dyno Mapping

[JesseGray]

I am about to get my 97 dyno tuned. They asked if I want to have it mapped.



Dumb me, I do not know what they mean by mapping "it".



Thanks.

 

[HBarlow]

What do the "dyno tuners" propose to do for you and what will it cost?

I'm skeptical about what will be tuned and how you will benefit.

 

[JesseGray]

I am not certain what they can do for me. That was the reason for the question. If however, they cannot do anything for us, why do all the Dodge owners take their trucks to "dyno days?"



I do not know. What they said is below:



Dyno tuning is a systematic approach to engine tuning. Dyno tuning allows us to give your vehicle a tune-up of unparalleled quality, providing you with the smoothest, most economical performance possible from your vehicle. To properly tune your car and program the computer for the best performance and fuel economy under all loads and driving conditions, your car needs to be on a dyno with full load control. Nothing makes engine tuning more precise than a full load dyno. For each RPM range our dyno can put various loads on your truck to simulate all conditions on the road.

We are able to simulate different driving/load conditions, diagnose drivability issues “in the shop” (while using other diagnostic equipment, i. e. scanner, scopes, gauges and meters), check horsepower, torque, and air/fuel ratio.

 

[JesseGray]

From what I have read, on a dyno, they can simulate my truck pulling the 13K fifth wheel and where it may be loosing horsepower, or even how much horsepower I am producing at the rear wheels.



One gentleman I spoke with said that he put his truck on a dyno each and every time he made a modification to his engine and power train to very that he was in fact improving his performance rather than detracting from it.



As I mentioned I am new to this. There are people here at TDR who will have forgotten more than I will ever know.

 

[HBarlow]

Jesse,

Be careful with your wallet. What you posted was apparently from material obtained from the folks who want to sell you the fancy dyno tune. It was only lofty sounding rhetoric with no substance.

My specific question is what will they determine from the dyno result and how will they alter your engine to improve performance?

Your 12 valve Cummins is a basic hard working truck motor. There are no carburetor jets to change to adjust fueling, no ignition timing or distributor advance curve to alter or adjust, no spark plugs to regap or replace with a different heat range plug.

A knowledgeable diesel tech can change the fueling plate on a 12 valve or change the upper rpm limits but there is very little that can be done other than adding high dollar performance parts such as injectors, turbos, etc. which always produce an unintended consequence. Every action will create a reaction.

I would recommend you get out your stack of old TDR magazines and read everything you can find with Joe Donnelly's name on it. Also go back ten years and read all of the 12 valve threads here in TDR website. Lots of guys here know a lot about 12 valve Cummins engines. I don't know much of anything about them so cannot address any specifics.

Its your truck, your money, your choice but you asked. I would not spend any money on so-called dyno tuning.

And, BTW, I would not use a K&N air filter where desert sand blows.

 

[seafish]

Likely "mapping it" means actaully giving you a copy of the HP/RPM x/y axis chart that all dynometers produce. These are simply the HP/TQ dyno results in an ez to read format.

People here on TDR and other sites like to have a copy of the chart simply to know the peak HP and TQ that there CTD is producing. It is good for bragging rights only, not tuning a CTD.

That being said, using a dyno chart to interpret results from changing parts or programming will tell you whether or not the part or software tune actaully added HP or simply added "bling", BUT keep in mind that there is a dirty little dyno secret that no one actually talks about...

On ANY given set of back to back dyno runs on the same truck at the same time, may vary by as much as 5%, even with a "skilled" dyno operator, as RPM and increased fueling based on turbo spool is the biggest contributor to HP gains in the results, and RPM and heat DIRECTLY influence turbo spool-up and they WILL vary from run to run. What that means to you, or anyone, is that any changes in peak HP or TQ that are less then 5% from a previous run may or may NOT necessarly mean an improvemnt in HP output due to a parts change, even though you will have the dyno chart to PROVE that your peak HP/TQ increased 5%!!

All that being said, the bragging rights are STILL fun. Just not necessarily worth the money, which is why most people go to dyno day events when there is no charge for the dyno test.

As HB points out, using a dyno to tune a gas engine, where you can actually easily change timeing and fueling might be a very different thing then using it to map peak HP/TQ on a CTD.

 

[GOlsen]

I think mapping is changing the fuel mapping curves (which would apply on a gas engine). There are no performance gains to be made by programming the computer on a 12 valve as it controls nothing for the engine. If you want to run on a dyno and get a good baseline hp and tq levels, go for it, however, I would stay away from the dyno tune.

 

[JesseGray]

Dyno Tune

Got it! A dyno run is good for a base line or bench mark and bragging rights, but most other adjustments can be done without a dyno.



Thanks HB I have heard and seen where my K@N is letting dust through. When they close I-10 through my part of AZ and NM because of dust, I see that this K@N thing is a problem. What about a BHAF, or stick to an AFE?



I do spend considerable time reading back issues of TDR, and I have been through the TDR Buyers Guide numerous times and before asking questions.



Thank you, Everyone, for your assistance and comments.

 

[GAmes]

I know that Harvey doesn't have any faith in after market air filters, but I like my AFE 7. After 800,000 miles there was very little wear on the cylinder walls of my old engine. They flow more air than a stock filter so are good for moderate HP improvements.