Maybe a point, accuracy doesnt matter if you've got the only accurate measurement device in a sea of precise but inaccurate devices.

 

Dynojet 228/248 is only approved dyno for NASA and SCCA. Why run a mustang unless that's the only thing around. Accuracy/consistency... you don't have a choice of your competing in either.
The only way around that is if you've got awd

 

You cant tune on a dynojet, you can on a mustang. I prefer to tune on a dynapac though because of the super low inertia and amazing control of load, and of course no tire slip possible.

 

and a dyno that can be manipulated by the user has neither.

sorry, after seeing hundreds of inflated and "corrected" mustang and dynodynamics dyno results I've pretty much lost any and all faith in "dyno accuracy".

I'd go as far as to say there's accuracy with consistency. As long as you know the baseline vs finished numbers, you get repeatable results that you can at least somewhat compare with others.

PS: what I find most hilarious is everyone uses the "mustang dyno" disclaimer and the 10-15% lower reading regardless of whether that's actually true, and it makes their numbers look amazing.

I'm not saying that's what Cord is doing here. I would tend to completely trust the plot and disclaimer in this thread specifically. So OP, this is not aimed at you at all

 

Everyone pretty much corrects to "Dynojet" numbers just to show apples to apples. I prefer an inertial dyno so steady load can be placed on the engine during tuning--it gives the tuner some extra tools to play with. I personally wouldn't care if the dyno read "100" as a baseline for every car, and then gave the ratio of improvement as you tune.

This particular dyno is 9 minutes from our shop, so I probably won't be venturing out for alternatives.

Last, we were picking up some detonation right after the session and I'm beginning to think that the carbon build-up from the previous rich tune was causing some "hot spots" on the pistons. We've backed off the tune, but I think the horsepower will pick up more as the crud blows out of the engine.

 

Because for the purpose of engine tuning, you want a load-bearing dyno that can hold the engine at a constant RPM while you manipulate the settings of that one particular column in the table that you're working on.

Dynojets are great for making back to back comparisons between different cars, but very few of them are equipped for steady-state operation. The two types of dynos are different tools optimized for different tasks.

 

I guess I'm spoiled then. My tuner has an Eddy Current load-holding Dynojet.

 

Yeah, the eddy brake is an option on most Dynojet models, but my experience mirrors Cord's in this respect. Five years ago, I went crazy trying to find a steady state dyno in the same town, and couldn't find a single one. I wound up working on an inertial-only Dynojet at a shop that did mostly drag cars, and it was slightly frustrating.

If I were a shop owner interested in catering to the "three pulls for $50" crowd, I'd get a Dynojet. If I were a tuning shop or was focused on engine development, I'd buy a dyno that was inherently steady-state, rather than tacking on an optional eddy brake to a huge, heavy inertial model.

 

That certain shop you're talking about is the same distance away from our shop as the eddy current dyno, in the opposite direction. They won't get my dyno business, but I was going to take my 1.8 engine there for a quickie rebuild.

 

One other point; Bill had zero experience with the MSPNP software, as his specialties are Subie, GTR and Porsches.

Bill familiarized himself quickly with the software, adjusted the VE tables and then took the time to calibrate my "14point7" wide band sensor. He made sure that the changes he was making were essentially correctly reflected in the tune.

When he was done we had a 22 year old engine with a chinacharger and FM supporting hardware putting out some really good numbers.

Suffice it to say that the Subie faithful in the shop we're really impressed with the figures, and maybe a little worried. .

 

This is the surprising shop, most subie shops are all "here is this tune I made once for a guy with similar mods to you on an access port, thankyou for the $500".

 

Should be a hoot to drive at that HP level. IIRC Ron Cortez got 200whp on his Catfish using a Rotrex. It was very competitive in class at the 2013 25hr race.

 

The HP totally transforms the car, from sports car to high performance sports car. The difference? Having to recalibrate your senses because everything happens so fast.

Ron and Oscar Jackson had a solid race plan, but then 25 hours. The first year we "beat" the factory Audi TT in our class, mainly because they broke. Last year we broke...well, we couldn't avoid missing a car that was limping along on the racing line. At night. With no lights...

I can't wait for this year's race on the "Thunderschleiffe". A long track brings other considerations, and it will be really interesting to see who has the answers.

 

Absolutely true. Subie owners tend to do the same things to their cars, and Cobb has done massive development (hundreds of hours) to tune these builds. These guys are used to getting three different tune maps--street, track and strip.

 

Took some pictures as the sun went down over Oceanside Harbor tonight.

 

What an incredible looking car. Would drive. Wow.

Great job, sir.

 

Good god, that looks fantastic.

 

Thanks guys. .

 

Idle question, are your cars available RHD / can you export kits to the UK.

My old man is considering building an MX5/miata based kit car....

 

Yep, RHD has been researched and can be done easily. BTW, the next issue of Kit Car UK will have a feature on the Catfish.