Send us your testimony>>> Testimonials

Read the testimonials of clients satisfied with the service they received for their heavy truck tuning. Our clients come in with vehicles from the following brands: Detroit Diesel, International, Mercedes, Paccar, Caterpillar, Cummins, Isuzu and Hino. We offer our services to optimize the diesel engine performance of a variety of heavy trucks.


The following clients called upon Diesel Spec’s expertise for all their heavy truck diesel engine repair needs.


We offer our clients various diesel engine tuning solutions, including enhanced engine performance, off-highway tuning, components installation and more. Diesel Spec is an expert in this field: see for yourself with testimonials from satisfied clients! Trust the Diesel Spec team with your heavy truck to improve its diesel fuel economy, horsepower and performance. After it’s been tuned, your truck will have the extra kick it needed to reach new heights! 

Menick Lebeau , Quebec

Thanks to the Diesel Spec team for your professional work! Not only is my truck more fun to ride since you upped its performance, but I also make fuel savings of 1 mile per gallon. I recommend all truck owners to visit Diesel Spec.

- Menick Lebeau , Quebec

Louis Gauget, Mexuscan cargo

I went from 5.7 mpg to 7.5 mpg with my cummins ISX 2009. I should have done this a long time ago... Thanks to Diesel Spec team !

- Louis Gauget, Mexuscan cargo

Danaso Transport

Thanks for bringing my engine back to life! 100 horsepower more and a fuel saving of 10 %. Tremendous investment! :)

- Danaso Transport

Eric Arsenault , Arsenault transport

I am saving 15k per year in fuel with my Caterpillar twin turbo and I have less downtime. Can't ask for more! Thanks guys !

- Eric Arsenault , Arsenault transport

Philippe Gaudet , JCB Transport

Here is our 2012 Western Star glider with a 7CZ series Caterpillar C-16. Diesel spec tech, Ian Rees did us a tune to give us the extra kick we need when going in the dirty spots pick up or deliver heavy equipment. It does all the difference between getting stuck in that steep hill or going up and back.

- Philippe Gaudet , JCB Transport

Jarnal , Falcon Express

We @ Falcon were looking to improve our fleet’s fuel economy. After reviewing the results of the first 3 truck tunings with an increase of 0.5 to over 1 mile per gallon and an unexpected performance increase (drivers like the power less shifting). Diesel Spec has tuned over 40 trucks for us with detroit diesel engines in the last two years.

- Jarnal , Falcon Express

Mario Racicot , Transport Racicot

Thanks to Diesel Spec for making my truck the strongest working truck in Canada with over 2500 horsepower !

They also did all my Cummins fleet with amazing results on fuel economy.

- Mario Racicot , Transport Racicot

Mario Banville , Transport Banville

Thanks to Diesel Spec for giving my Detroit Diesel DD15 the power I needed, while helping me save fuel.


Also a big thanks for my Racing ECM on my Serie 60 that revs more than 4000 rpm :)

- Mario Banville , Transport Banville

Jim hunter , Keewatin Truck

Here is  a picture of Mike Whittar and his truck..Since doing the delete he has never had an engine light come.Very impressed.Good power  great fuel mileage.

- Jim hunter , Keewatin Truck

S. Giasson , Transport Masyna

I had my C15's ECM adjusted and I can now save $$$$$ on fuel. I am very satisfied! P.S.: Thanks also for my racing ECM... we finished 2nd at Baie-du-Febvre, 1st at St-Joseph-de-Beauce, Class C, and 7th for weigh pulls this year. Thanks to your team!

- S. Giasson , Transport Masyna

John . JNB Heavy Haul

We at JNB Heavy Haul need all the power we can get without sacrificing Fuel economy.More than 30 trucks done and very satisfied.


Diesel Spec delivers BIG in both.



- John . JNB Heavy Haul

Deepland Transport, Deep

Diesel Spec as done tuning to  all my Volvo and Caterpillar engines. Average of 12% fuel saving on each of them. Thousand of dollars in my pocket each Month. Great services and customer support.

- Deepland Transport, Deep

René , Transport René Boucher

Thanks for allowing me to save thousands of dollars in fuel and making my engine so much more reliable in the past 2 years.

- René , Transport René Boucher

Paul Carter , New Brunswick

I have 2011 peterbilt 389 with 2010 cummins 485 non def .i hade it redone at JGC DIESEL in hardwicke n.b. since the work i have gained .9 per mile average since it was done in sept of last year.truck was set at 500 has a 10spd over with 4.11 24.5 rubber hauling quad gas trailer . gross 120000 lbs.i cannot believe i have went six months with no check engine lights better power and oil stays clean until oil change at 20000 kms (still gold )VERY HAPPY !!!!!! 

- Paul Carter , New Brunswick

Christophe, Belgium

Following the purchase of a motorized W900L by a C15 Caterpillar Accert in 2011, which I'm not very happy about (quite a coffee pot of an engine and fuel-thirsty), I was looking for a person to modify the ECM. Thanks to your company who made a new ECM for me, things changed. My truck is now very powerful and fuel-efficient. This adjustment was made 3 years ago, and the truck is used 24 hours a day, 6 days a week. I have no problem so far. I wanted to thank you for your knowledge and your expertise. The cost of the transformation can be a bit scary at first, but with the fuel savings, I was able to pay for it within 6 months. Sincerely,

- Christophe, Belgium

Transport Transkong, Italia

We specialize in heavy-load transport. Important power gain and amazing fuel efficiency.

- Transport Transkong, Italia

Transport PKM , France

We are very satisfied with the recalibration done by Diesel Spec in Canada. We gained 4 liters per 100 kilometers on a Cummins ISX-600 with and extraordinary performance. Thank you!

- Transport PKM , France

Dave Wanless ,Ontario

Dear  Diesel Spec,

It was a pleasure to meet you at the truck show in Toronto on Saturday last. I finally got to meet one of the people from the company that designed the program that really zipped up the performance of the truck I was driving.In early March, 2013, i sent my truck to All-Equip in Stratford for a major tune up. This truck is a 2006 Freightliner Classic with a 14L Detroit set at 515HP. I haul grain, feed and fertilizer in a 2005 Stargate 4 axle end dump, grossing 59,500KG in southern Ontario.(2-4 loads per day depending on distance & time).Did I mention POWER and TORQUE? WOW! It was like I had 2 engines under the hood. I was now ascending hills at least 2 gears higher. What a joy to operate! Example; 401EB in the hills between Bowmanville and Trenton, I never had to drop a gear.Fuel mileage was 4.5 to 4.8 MPG CAN and within 4-5 months it was up to 6.25 - 6.5MPG. Don’t forget, I’m always heavy, a lot of stop and go and hilly terrain. Most of the other trucks that do the same work are getting 4.5-6MPG. So this is defiantly a benefit. I would highly RECOMMEND your upgraded parts and ECM tune-ups.

Thanks again for the WOW program!

- Dave Wanless ,Ontario

Frank , Gibson Transport

Here I got a Ecm tuneup done on my Maxxforce engine at advance tune-up and im happy with it. Im getting about 1mpg better on fuel and i gained a full gear on all hills. Im happy.Thank you.

- Frank , Gibson Transport

Tyler, Dingman Trucking

This is Tyler from Dingman trucking we did a Caterpillar bridge engine tuning . Truck now pulls great and good on fuel . Cat engine was lazy before . Thanks guys !



- Tyler, Dingman Trucking

Doug Ruddick , Texas

2007 Kenworth w900b with Caterpillar C-15 mxs twin turbo. I have the economy tune on my truck and right away you can feel the difference. The truck pulls better, uses less fuel and seems to run a little cooler as well. I've have one truck done with finning and one with diesel spec and diesel spec is for sure a better way to go!

- Doug Ruddick , Texas

Dale Siemens, Alberta

This is dale Siemens from dale Siemens & sons trucking new Norway AB. 2009
Cummins ISX we did egr & dpf delete the unit did run well before got about 3 mpg low
on power and now power is great and up to 6 mpg pulling tri axle belly dump
.Done at Murray's truck parts locators in Camrose AB. Thanks Diesel Spec !

- Dale Siemens, Alberta

Kevin Quinn, Laidlaw

I had my Caterpillar C-13 tuned by DSI. It is now greaaaaat on power and better fuel mileage.TY Diesel spec !

- Kevin Quinn, Laidlaw

Georgi Tcherkezov , Jaguar Transport

 I am happy with the job you did .... Don't see a check engine and don't see Freightliner dealer for 750 000 km. Doing 2 mil.par gallon more than the original set up. This is priceless !!! 7 .mil par gallon with 650 hp. 14l. Detroit. Thanks Chris and have good luck at the Bass tournament !

- Georgi Tcherkezov , Jaguar Transport

Meo, Transport Nesko

Vous avez faites des miracles avec ces camions, donc le mien qui était le no. 24. Après que vous l'avez ajusté, j'ai gagné beaucoup plus de HP et 1.3 Milles aux gallons de plus, l'économie de diesel était surprenant. De mon côté, j'ai bien confiance en votre travail et continuer car sa n'en vaut la peine.


- Meo, Transport Nesko

Guillaume Rosset, France

Un énorme merci à la team de Dieselspec de la part d'un jeune routard qui commence à peine à manger du bitume comme on dit. De grosse économie niveau carburant avec un cummins ISX-600, à vrai dire inespéré! Service pro, nickel. A plus sur la route!

- Guillaume Rosset, France

Hans Humburg

Thanks to Diesel Spec for Tuning my truck. Saving 1mpg and great power improvement.Just what i needed.Great team to work with !
Hans Humburg

- Hans Humburg

Fred Polet ,Strathmore Alberta

Just would like to say thank you for tuning my ECM on 1996 N14 Celect Plus .  Truck runs smoother, more responsive and the power is beyond my  expectations .  Thanks for a great job and great service.


Strathmore Alberta.

- Fred Polet ,Strathmore Alberta

Fedex Canada

Thanks to Diesel Spec to made my Cummins ISX runs with more power and better fuel economy ! Great place to deal with smile face.

- Fedex Canada

Brandon, Cincinnati Ohio

Hello, my name is Brandon I am an owner operator out of the Cincinnati Ohio area, in 2015 I bought a 2012 used International Pro-star with the Maxx Force 13 engine, my first mistake. In February of 2016 the problems started, after $30,000 in repairs and every part of the emissions replaced, the Egr valve, Doc chamber, DPF filter, two Egr coolers, plus various sensors I soon found out why Navistar was under so many lawsuits. Now it's February 2017 I start loosing horsepower and coolant again, so I took my truck back to the local international dealer who previously performed all the work, after four hours checking my truck they came to me with a $9,000 plus repair estimate, the Egr valve and Coolers once again, my warranty just ran out, just my luck. So instead of allowing this truck to eventually bankrupt me I called Diesel Spec of Canada, they were very informative and test their products on the engines there selves. They gave me a number and address to an associate of there's in Tennessee just east of Nashville, when I called, Chris answered the phone he was very pleasant and full of information, I drove my truck Bob tailing 306 miles to get there, when I arrived he knew more about my Pro-Star than international. Chris then took me to a local hotel it would take him a day and a half, 4 ours later Chris called me to inform me that he found a coolant leak and a boost leak he fixed both problems. The next morning he called and told me he was finished came back to the hotel and picked me up, when I went to pay the bill the extra work he performed fixing the coolant leak and boost leak was not on the bill, he spent his own money and time to repair my truck before performing the Egr delete to ensure my truck left his shop operating at 100% wow who does that? Normally my truck bobtailing gets 9.9 mpg when I left  Tennessee to go home I could immediately feel the difference in performance, after another 306 mile trip back home by paper my truck had a 2.1 mpg increase awesome, by the truck computer I had a 2.5 mpg increase, I cannot wait to see the Performance increase while being loaded until then thank you Diesel Spec for your products and allowing me to feel more confident in my trucks reliability, and money making capabilities. I would definitely tell anyone about Diesel Spec's product and advise them to try Diesel Spec first plus the garage they sent me too was top notch I have never been treated so good by any diesel repair shop before, I will give a later update in a month or until then happy trucking.
Thanks Chris @ Revolution Diesel for great work and customer service.

- Brandon, Cincinnati Ohio