Word travels fast. Word is out blue car blew up on the dyno. I am tired of people asking why so here is my take on what happened and why.

On Thursday the day S&R first started dynoing cars I was present to watch the dyno in action. During testing the first two cars I could see the dyno operator was having some teething problems on how the dyno was to be used. There was clearly too much load present on the rollers. It was clear the cars were struggling to make it through the power band. The second car on the rollers was a Subaru Sti. It was held at 3000rpm in third and when the load was engaged the rpms quickly dropped until the motor stalled. At this point I realized they had better learn how to get the settings straight as they were scheduled to dyno tune 15 cars that weekend. I had to get home so I left. on Friday I returned and I asked the operator if he had figured out the load problem. he said "yes, it was user error. We dynoed two more cars the last one only took nine minutes from start to finish" I thought to myself cool if it only takes ten minutes maybe he will dyno my car for a freebie to get more practice. So I asked and he was more than willing. I wish I could get that ten minutes back. We attempted do a pull to 6500. At 5400rpm the engine violently blew a head gasket. When it happened I didn't know exactly what had happened. I was not happy and very confused. Most of all just plain embarrassed. I drove in with a perfectly running Evo, that happens to be my daily driver.

First assessment at the dyno. Not good. It was clear the engine got very hot. Cylinder compression came out the radiator. I mostly concerned that my pistons would be hurt or maybe even the cylinder head as I know when you blow a gasket that badly it usually burns the head beyond repair. The only gauges I was watching during the pull was my wideband and tach and one quick glance at boost. The boost was 1.6 bar and the wideband was reading 12.4. Unfortunately S&R view at the time was the car was just tuned lean. The dyno wideband was only reading 17:1 A/F so in their mind the car was not tuned correctly and its no surprise what happened. Quote: "Congratulations for being the first to blow up on the dyno!" So I leave immediately to go get a tow vehicle. When I return there is a 240 on the dyno making a pull. His car also shows lean A/F in 16-17:1 range. He just came from a different dyno earlier that day where his A/F was 11.5:1. This proves the brand new wideband was either not working correctly, was not calibrated or was working intermittently.

Now to the damage. The engine struggled to go through the power band, as I had noticed earlier with the other cars. Now my car makes some mean torque so while it is not zipping through the RPM it did feel like it was pulling cleanly. I was concerned with the 12.4 A/F as the car was tuned 10.8-11.4 on the street. . but I have tuned it to 12.0s before while logging to see if it felt stronger. During tuning I noticed no knock at 12.5 but the car didn’t feel any stronger so it was fattened back up to be on the safe side. I only run 23-24psi with 93/alky. The car was pretty safely tuned or so I thought. Remember this dyno pulls only last seconds, there just isn't enough time to make intelligent decisions sometimes. I was just there to see some HP numbers, I wasn't there to tune. If I had been tuning a car from scratch I would have been proceeded with some care. This likely would not have happened. I know how to tune cars. My cars are always fast and never blow up during high speed races. This car was no exception. I just came from racing a 600whp stang and a gsxr750 the past two weekends with excellent results... When I get the car home I pull the plugs. at that point its all starting to hit me. This engine is toast. All four electrodes were burnt. After pulling the head my fears were confirmed. Melted number 4 piston. The gasket blew in a small spot. when the cylinder compression (likely 4000psi plus when detonating) entered the water jacket the water itself violently entered the chamber and cut a groove through the cylinder head. Very much like those high pressure water cutters you see very capable of slicing through metal like butter.

So how much load was there? This type of dyno is a load bearing dyno. These dynos are known to be able to place the same load the car sees on the road. They are able to dyno motorcycles that have minimum load and big diesel truck with maximum load and anywhere in between. In effect if the load is correct the engine should rev through the power band just as it would on the street. If it takes 3 seconds to rev from 3000-6000 on the street it should take 3 seconds on the dyno as well. If it takes longer than 3 seconds that means the load is too high. My car on the street in 3rd gear will go from 3000-5400 in about 2.5 seconds. With five adults driving up the skyway bridge it would prolly take 3.5 seconds. On the meltdown run it took 13 seconds. I have watched countless dyno runs of all sorts of different cars, when full throttle is hit and full boost achieved the run only lasts 2-3 seconds. And it’s a good thing because dynos can never duplicate the valuable airflow over the inter-cooler and radiator.

So why did more cars not blow up? Mark French has extensive dyno tuning experience with all sorts of dynos. He tuned all the cars with inertia of the rollers only, no load.

This thread is not to bash S&R in any way. I just felt it is important to set the record straight on what happened. I am 100% certain my car would not have blown up on any other dyno. I am 100% certain it wouldn’t have blown up on this dyno if the load was set correctly. There are 100s of people who can attest to how well the car ran. As far as I what I expect to happen from this I don’t know. There are plenty who feel S&R is responsible for the damage that occurred. I work on my own cars and wouldn’t dream of other hands touching my car. I am interested in hearing S&R side as to what it right and what is wrong here.

melted no4 piston

cylinder head, nice chocolate color prior to the 10 second overheat

close up of damage to no1

gasket leak at no1

spark plugs on left from 3 days prior, nice chocolate brown, plugs on right from severe detonation

 

Damn....I was reading your sig there

and I was going to make a joke about how now my Caddy could beat your blue car...but seeing as how my motor is also out for a rebuild, it will be teh quickest car PUSHED to teh finish line wins...and my car weighs a bit more then yours.

anywho...sounds like somebody needs to learn how to operate a Dyno. It's no fun when faced with expensive breakdowns for no reason other than inexperience.

-Charles

 

The 240sx that you mentioned was built at my shop. Just earlier that day, it was dynoed at XAT with perfect A/F tuned by Martin. The customer came back to us after dynoing, completely confused. We were able to call Ellis Autoworks at the last minute and they got the car in, it was very appearnt that S&R's dyno was not properly setup. Just adding my .02.

It's was funny, I actually saw you towing your car down Busch and was with Kirk, wondering what the hell happened. I was actually heading down to Advance Wheel and Tire to see their new place. Then I get a call from the customer with the black 240sx, almost not wanting to drive his car, because he claimed that his A/F was averaging 16+.

Hope everything works out for both parties.

 

WOW is there a way that you can see the load settings oon your run??

 

That's a good question, I'd say yes.

 

Interesting read. I've always felt like running a powerful turbo car on a dyno was playing with matches. You race the car on flat ground, don't see why you can't tune on flat ground with the proper logging tools. I hope you get it all back together and running well.

 

you need a dyno to set timing good. you need to see your peak torque. you wont be able to tune your car on the street like you can on a dyno.....although you can get a pretty good street tune with proper tools

 

id also like to see how s&r handles this since they seem like a nice honest shop

 

that is a very good question BUT.... did he contact them b4 this thread and give them a chance???

 

He also states he was NOT tuning the vehicle on the dyno, only put it on to see numbers.....

The car was already tuned and running well.