This is the tale of three little Dyno’s - - a DynoJet - a DynoDynamics - and a Superflow WinDyn

I thought I would share my “Dyno” experiences with the forum. I know some members have been elated with their dyno results, some perplexed and some down-right disappointed. I’ve had my SRT6 on three different dyno’s now and have pieced together some info that might be useful to others. Those with more experience or insight - feel free to add...

Basically what brought this all about was a visit to a dyno shop last night for few runs. I figured I was pretty much done with performance mods for a while and I knew SRT6 Dan had used this local shop and posted his stock SRT6 results on the forum. I figured it might make for a good reference for me. Also, other forum members have asked me for dyno results to help them with their mods so I thought - - let’s do this now. This turned out to be one interesting evening.

I had called and made an appointment at BBR (they are not an everyday shop – in fact the space is just used as a hobby shop by the owner and he only does dyno’s three evenings a week and on Sat by appointment) No sooner was my SRT being setup on the dyno when Code3 himself pulled up -- Well OK I thought – I guess he made the hour + drive down to see the “competitor’s pulley” run. I’ll admit that I was a little evasive at first – I just wanted this to be my time on the dyno and not to try and “measure up” but soon opened up about my mods – but as the night went on …..

Let’s leave it there for now and have a look at some older dyno charts. Sometimes they speak louder then words….

Below is my first Dyno after I purchased my SRT – not knowing what to expect or how to ask for proper graphs – it turns out that Andy at the Corvette shop that opened up his dyno to me (he pretty much just uses his DynoJet to tune the performance mods he installs for Corvettes (650+ HP modded Vettes that is…) I though it might be useful here because I returned to him today…. But let’s go on… this the proper way to set up a customers dyno graph. The same parameters for HP and Torque on both sides and engine RPM on the bottom. I didn’t ask for this; Andy just knew. I did not ask for AFR because I didn’t know, but that’s all part of the Dyno education. 267.5 WHP and 263 Torque: Notice how the Torque curve is high above the HP curve until they interest. Keep this in mind.

SRT6_Stock-1.jpg

Here is dyno pull #1 on a DynoDynamics @ Gintani/Speed Innovations after I had installed the SL55 intake, 185mm Pulley and Iridium Plugs prior to the tune. The AFR was 10.5 – 11.0. This graph was poorly setup because the Power and Torque references differ on each side and the bottom should be displaying engine RPM – This was my fault - You need to make sure you ask the operator to set up your charts correctly - you may want to a printout that is different then what they need to see.

Next is a screen-shot of the Power-Torque-RPM website that converts these DynoDynamic numbers to DynoJet numbers – this comes into play later when we see just how accurate all this is…..

 

Below is dyno pull #20 (green) and #22 (red) (same day) after all the tuning was complete. Followed by the chart showing the AFR readings from the same runs. SI had a probe that sniffed pretty deep up the exhaust with the wide band mounted on the end outside the exhaust – this made for some pretty accurate and stable AFR readings (this will come into play later) Notice how the torque is nice and high above the HP line at the beginning of the run?…..


After_tune-1.jpg



After_tune_With_AFR-1.jpg

Here is the screen shot the converts the 308.1 peak HP Dyno Dynamic results into DynoJet numbers - 362.47 HP – can this be right?



After_tune_PTR-1.jpg

 

Well, now I’m at BBR with my SRT on the dyno and the first two pulls sound like my granny was behind the wheel. Slow acceleration never hitting the limiter – producing very disappointing numbers. But it seems revenge is always mine – on run #2 my oil dip stick came loose and my SRT shot oil all over the shop.. Also my AFR readings were all over the place. Well, I was told that the 185mm pulley was making way to much boost and causing me to run lean and thus not making HP - - etc etc… But then after some clean up time at the shop- and when it was just me and the owner (and a few kids looking to fill their nitrous bottles) I asked him to hit the rev-limiter on Run #3. It was still a dog pull but here are the results followed by the AFR charts.

Notice how low the torque curve is compared to the other dyno charts – notice the top of the charts says “Dyno Comparison?”



Bottle_Blown_Blowup-1.jpg








Bottle_Blown_Blowup_AFR-1.jpg




The good part about this run is that I reached 361.7 Peak WHP - very close to what the website that translated my DynoDynmics (308.1) numbers to DynoJet said…

But wait – my SRT is sitting on at SuperFlow dyno… Turns out I saw them looking at other charts after run #2 (there was a remote monitor) - and I saw some sort of conversion with my dyno my chart while comparing it to some other runs.

I don't know why BBR could never get my SRT6 into the Dyno mode. My ECU is setup to run to 6,150 RPM and the BAS and ESP light should illuminate. (A special feature of the SI tune – no external settings required and no fuses to pull to get into the Dyno Mode – just strap up and go)

At the end of run #3 I asked what was up with the different charts (Dyno Comparison)? Turns out this system will convert the SuperFlow data charts into DynoJet charts. I wonder now If I hadn’t asked him to hit the rev limiter or had seen this conversion feature, just what my peak HP and Torque # print charts would have looked like compared to …… – well, I think you know.

Take a look at the other charts posted on the forum from this shop – look how similar the curves are to my other charts – notice they are all labeled “Dyno Comparison"…

Now look again at the AFR chart – what had happened to my SRT6? - Turns out nothing, but I was concerned enough that I called Andy at the Corvette shop today and asked if he remembered me (it’s been a year) and my SRT6 – he did – I gave him the run down and he said bring the SRT over and let’s put her on the dyno. When I got there he was finishing up with a customer (08 Vette) over $6K in mods, an old farmer boy (I would guess about 70) from the central valley whips out a wad of $100 bills – Anyway – Andy looked at the charts and then looked at my tail pipe and remembered why he had not done a AFR last time (See Dyno chart #1). Turns out his sniffer is custom made for Corvettes and the probe wouldn’t t fit right in my pipe. He says he can disconnect the O2 sensor from the probe and clamp it on the very end of one of the exhaust tips and just sniff one side. He said it would read a leaner then a normal probe but it would at least give me a Idea and a second opinion.

So here is the Dyno Chart from that run – everything back to normal with the AFR rock steady at 13.5 (with a proper probe up the exhaust pipe I would say 12.5 – 12.8) - so based on this and my DynoDynamic tuning charts (and I’ll pull a few plugs tomorrow) – I’m positive my SRT6 is just fine. Also pretty happy with the peak HP of 350.75 considering it was around 35deg warmer and a bit more humid today VS the weather last night.


DynoDynamics_3-1.jpg

Bottom line is make sure the Dyno shop and operator you use are experienced, that you know what to do and how to get your SRT into the proper dyno mode and don’t be afraid to ask for the Charts the way you want. I also suggest sticking with a DynoJet or Dyno Dynamics, or Superflow because it looks like the conversions are pretty accurate and solid.


Enjoy the weekend!!!!!

BB

 

Nevermind all that dyno BS.

How well does it get down or around the track?

 

One of the tuner magazines did an article on dynos a few years back - took the same vehicle to 7 different dynos on the same day and got high to low variance of 58HP. Given the moderate HP rating of the vehicle that 58HP was an enormous variance in percentage.

All this is why one should never compare dyno numbers from one car to another when the pulls were made on different days, different dyno, different technician, different ambient comditions. Yet we always see people bragging about their dyno numbers or crying because their car didn't dyno as high as someone else on the forum.


Please note I'm NOT specifically talking about Brian here, or anyone else on this forum. Just speaking generally.

Brian, nice to see you spending the time and money to do this.

 

Pretty good read, even if I'll never be on a dyno its still an interesting story. All I care is about is my car whips my neck back when I hit the gas and sticks to the road when I swing around curves!

 

Excellent write-up !

Words of wisdom above.

 

Just like the new GTR out of 4 cars tested, it varied over 1.1 seconds in the quarter mile. It's all about conditions and very hard to duplicate unless your in a climate controlled atmosphere. You should have gotten DA from all there pulls. It might have showed a few hundred feet differences or more.

 

Brian, great bit of information... Most of the sanctioning bodies, SCCA, IMSA, NASA etc. require dynojets for annual tech inspection because it is believed that they are more accurate. Who knows for sure...

You're doing great with your car... Can't wait to see it when I get back to LA.

 

The biggest drawback to the Dynojet is also its biggest strength - the lack of ability to apply a dynamic load to the roller means that numbers are generally more consistent from machine-to-machine, all else equal.

As noted by the OP and others, the operator is usually the biggest variable.