^^^+1. Dyno time can be quite affordable if you factor in the $$$ to pay speeding tickets.

 

Dyno time isn't the issue. My main questions stem from being able to reliably monitor & detect detonation with an AP1 and piggyback. Whether I'm on a dyno, track or street, I'd like to know when my settings are inducing knock.

For the auto-x class I run in, standalone ECUs are not a legal option - hence the EMU piggyback.

 

I spent $200 for 2 hours (two 1 hours sessions) on a DynoJet last September, and have spent at least another $500 over the years on various dyno days or tuning sessions prior to that. However, I've done literally thousands of street pulls like these without a single ticket. I've also gotten a much better tune, since I don't think you can get a good tune on a DynoJet. I haven't used any other Conventional dynos for tuning (DynaPack, etc.), but I would expect them to have the same issue with heat soak. Every DynoJet pull I;ve ever done has shown varrying / sporadic AFR's and timing due to unrealistic / inacurate IATs and/ ECTs, but that doesn't happen at all on a good street dyno.

Basically, unelss you work with a dyno like the one below or install a DynoJet in a wind tunnel, I can't imagine a better way to tune than a good street dyno. Of course, the only conventional dyno I have experience with is a DynoJet, so it the others overcome that heat soak issue somehow, I'd really like to hear about them. Brian, which brand do you use?

 

locally, i tune on a dynojet. i've tuned on a dyno dynamics and mustang dyno before when i've tuned out of town. i do some street tuning from time to time and i've had customers get pulled over doing pulls on the street lol.

how can you not get a good tune on a dynojet? for full throttle pulls it's perfectly fine. if anything i would say that with street tuning you wouldn't be able to get a good tune because the road isn't always flat and there are bumps here and there as well as drag that can throw off the datalogs. if you're working with a higher horsepower car you could possibly spin the tires and that could throw off the tune as well.

as far as heatsoak goes, it can be managed. how far off are the ect's and iat's? the iat's can very a lot but the oem honda iat's are a little slow with regards to adjusting for changes. i tend to see major heatsoak issues with short ram intakes. i can see temps anywhere between ambient and 120+ degrees on a hot day with a short ram intake on back to back passes. you have to let it cool down between passes. you can get heatsoak on the street as well.

 

eTunes are definitely a different story, since you can't depend on the WOT pulls being consistent enough. I also agree that higher HP cars would be more of an issue. However, if I'm dring an NA S2000 in one of my usual locations (in Mexico, or course), I get torque plots that are better than what I get from a DynoJet. I also know that I don't have to worry about the IAT and ECT compensations for fuel and ignition aren't jacking up my tune. After all, if you tune the car to have "ideal" ignition timing and fuel ratios while the ECU is applying significant amounts of compensations, then you really don't know how good those values are going to be when the car is being driven on the road. The fact that the IAT sensor is slow to respond just makes it that much worse, since the ECU will think the intake air is 140 degrees when it is really 95. Therefore, the ECU will be retarding timing when it isn't needed. Then the tuner will advance the timing to compensate...

 

i never see ect's fluctuating far enough to compensate for anything. once the engine in within' proper operating range, ect compensation is zero'd out on my tables. the iat sensor can be slow to respond but not slow enough to not catch such a big iat swing from 95 to 140. again, let the car cool down between passes and monitor those iat's between passes to make sure your iat's are within' range on every pull you're doing. you're over thinking this.

 

 

I've got to agree with Gernby about street tuning, i typically tune on a dyno but then tweak on the road.

However a good quality dyno with PID temp control, fans, external monitoring equipment, extraction etc can be as good - most dont offer this though. I seen a dyno over here that looked like a morgue/surgical operating theatre .

 

I don't want to start another conventional dyno vs. software dyno debate. I've just seen through actual data from BOTH that the heat soak causes significant differences in actual AFR and Ignition advance when the car is on a conventional dyno. Bsically, if I tuned my car for best AFR and IGN on a DynoJet, then I would later observe that my datalogs on the street would show leaner AFRs and more advanced timing than what I was getting on the dyno. Once I've filed my taxes, I'll post the datalogs to show what I'm talking about.

 

Absolutely, AFR's are leaner on the street.