congrats on the run Adam, my best time was 6.9 that was a 1/4 mile run. so I can't come close to your number. If your car is running that strong your gonna run high 160's as I ran a 164.5 with a measly 6.9 run. excited to see what the 997 and 991 run next weekend, game on

 

6.9 with a giac stg 2+ vs 6.6 with OTS stg 1

 

Congrats that's an excellent run! Amazing what a little E85 can do lol

To be fair though, not exactly a level playing field until a Cobb car runs E85. Correct? I don't know enough about the different fuel types and power production but I would imagine your results with race fuel and race map would be similar to others (both Cobb and Giac) and therefore this is not a typical result, would that be accurate?

With that being said, I can't wait for the platform to be able to run E85 safely and consistently, I think that's a game changer!

 

Hey what's up brother. Looking forward to hanging out with you next Saturday.


If your best 60-130 was in a quarter mile run, you have more than half to a full second gain on a dedicated 60-130 run, based on my numerous vbox runs at the drag strip, airstrip and 60-130 street runs.


Your 991 will be a lot faster than mine on a half mile. Beyond 130mph I'm gonna suffer heat soak from the stock intercoolers and timing reductions from elevated EGTs due to the stock exhaust/cats.

 

A couple amatuer-ish thoughts come to mind around the addition of E85 and the results/comparibility.

First, E25 is going to have a good bit less specific energy to it than standard "E0" 91. If you were to run a wideband O2 sensor, Im guessing you'd see the A:F slightly higher than GIAC would expect, given their tuning.

I'm also going to *guess* that GIAC tuned a car to the ragged edge of knock and A:F and then backed the tune down for safety before they called it the "OTS". Who knows when the fuel a customer grabs wont support the octane of energy density that a tune would need? Safety is necessary.

My last guess is that the DA at 5:30 AM on a cool morning in Southern CA was amazing. Cold air, cold intercoolers, etc. The car was absolutely in it's safest possible environment.

So I don't doubt that you ran an amazing time. But I'm pretty sure you were running the engine a little leaner than "OTS" in a really great environment.

No cheating, just optimizing and risk taking.

 

Why would a run starting at 35 mph or so, vs a run starting at 0mph result in a different 60-130 time?

Should be a great weekend with good weather. We will see you there.

 

Less heat in the intercoolers, and less chance that some lingering traction control/AH from under-35mph would hold things back later in the run.

 

Well I looked at my Vbox data from COTA and my best 60-130 there was 7.5s and that was on the grand stand stretch. Of course the track isn't as nice as the road that long ran his run on. The track definitely has ups and downs in every 60-130 that the Vbox data shows. I also looked at the AP data and it's even slower than what Vbox measures., more like the best I see there is 7.8s. Now I should say that TC is on when I am running at COTA but not at the drag strip. Anyway, my car is much slower but the IATs are definitely much higher for the data points I have on 60-130. We don't know what the IAT was on long's run but it's a single run on a cool morning so it's probably low 100s at the top end. Mine are typically 130-140 on the top end.

I would have thought the data from COTA might be closer to what long described since I come out of the curves at about 35-40 mph and then roll on the throttle to WOT before I hit 60. There were plenty of times in the COTA runs where I had the back stretch to myself and didn't have to move over to pass or slow down any because of cars in front of me. Anyway, the best time from COTA with a hot car running around the track repeatedly was 7.57s. I am pretty sure this is from the grandstand stretch. The second one is the best time from the back straightaway. In addition, this is with VP101 and nothing else. I filled the car twice that day.

 

My experience with 60-130 runs from zero vs 35mph is more or less .2 sec

But I guess that is me

 

Just for grins, here was my best 60-130 with the FVD piggyback on the car back in July. Of course I am sure the IATs were blistering but one can see how much faster the car is now than then. Part of it is bound to be the tune and some of it's going to be the heat. I didn't collect Vbox data in September.

 

You aren't guessing my friend...I can tell you have a lot of experience with this stuff.


I've been running e-blends for nearly a decade on other cars tuned for 91. Many dyno runs, airstrip testing runs, hundreds of logs. A little E absolutely sees higher AFRs. And every car responds differently.


I don't recommend this to others. This doesn't get the blessing of my tuners in fact some like ESS have said flat out don't do it. I do little blends...log and blend a little higher and log again. See what my cars like.


I agree it was good conditions and the car responded very nicely. But it was nearly a flat slope and more normal slope (neg 1 or more) on race gas would have likely produced better results. Is a high 5 possible GIAC tune-only? We shall see.

 

This is actually the exact opposite slope needed for an optimal run.


The highest negative slope should be at the end of the run. Why? Take a moment to look at your G-forces at the beginning of the run compared to the end of the run.


Yup you got it. The car is accelerating slower at 130 than it is at 60. Therefore to optimize your run the highest negative slope needs to come at the end of the run to "help the car out". You don't need negative slope at the beginning...you need it at the end.

 

In addition to what visceral mentioned, doing a dedicated 60-130 on a cool morning has huge IAT advantages as well...because you aren't sitting at idle lined up to race which heats up the intercoolers. This could give you another ~ 0.3 to 0.6 second advantage on it's own.


So you combine the effect of starting from 35 instead of 0 with the effect of much cooler IAT's and voila my friend, a half to nearly a full second advantage can be had.

 

We did run a mix of E35 about a year ago in the Pikes Peak 991 Turbo that we supported, and not only won but set the record for our class.

It does work but we tune for it when we do it. Any car using an AP can be tuned for a mix of up to about E55. So customers with the AP can take advantage of this gas just with a protune! Since we have full control over low and high pressure fuel system controls as well as short term corrections it can be tuned and tuned correctly using our software.

Great run!

-Mitch

 

Thanks for the words of wisdom... If giac would suppourt custom tune maybe Long's car saw a little of improvement vs other stg 1, but this numbers are to hard to believe with just that little of Ethanol and a OTS map.